Patent Description:
While current polymeric carbonated soda containers are suitable for their intended use, they are subject to improvement. For example, over extended periods of storage time carbon dioxide may permeate out from within such containers, thereby causing the beverage therein to become "flat. " An improved carbon dioxide generating system for polymeric carbonated soda containers would therefore be desirable. The present teachings advantageously include a carbon dioxide generator system that is able to extend the shelf life of carbonated soda, for example, by replacing carbon dioxide that has escaped from within the container with a controlled release of carbon dioxide from a carbon dioxide generator. <CIT> discloses using carbon dioxide regulators to extend the shelf life of plastic packaging. <CIT> discloses a cap body. <CIT> discloses fiber-reinforced, activated, zeolite molecular sieve tablets and carbonation of aqueous beverages therewith. <CIT> discloses beverage carbonation.

According to the present disclosure, a closure for a container, and a method for providing a closure for a container as defined in the independent claims are provided. Further embodiments of the claimed invention are defined in the dependent claims. Although the claimed invention is only defined by the claims, the below embodiments, examples, and aspects are present for aiding in understanding the background and advantages of the claimed invention.

The present teachings provide for a closure for a container. The closure includes a carbon dioxide emitter, and a release rate control layer that is configured to control release of carbon dioxide from the carbon dioxide emitter into the container when the closure is coupled to the container.

The present teachings also include for a method for providing a closure for a container with a carbon dioxide emitter. The method includes the following: identifying a volume of the closure; determining an amount of carbon dioxide to be released by the carbon dioxide emitter for extending a shelf life of a product stored within the container; determining a diameter of the carbon dioxide emitter based on dimensions of the closure; determining a thickness of the carbon dioxide emitter for
producing the determined amount of carbon dioxide to be released by the carbon dioxide emitter; determining carbon dioxide release lag time and release rate based on the volume of the container, the amount of carbon dioxide to be released, and the diameter of the carbon dioxide emitter; forming the carbon dioxide emitter by direct compression or injection molding; inserting the carbon dioxide emitter into a bore of the closure; determining copolymer with desired percentage of vinyl acetate to include with a release rate control layer configured to control release of carbon dioxide into the container from the carbon dioxide emitter; and over-molding the release rate control layer onto the carbon dioxide emitter.

The drawings described herein are for illustrative purposes only of select embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

With initial reference to <FIG>, a closure <NUM> in accordance with the present teachings is illustrated. The closure <NUM> is coupled to an opening of a container <NUM> in order to seal the container <NUM> closed. The container <NUM> can be any suitable container, such as any container suitable for storing a carbonated product therein, such as carbonated soda drinks. The container <NUM> is also suitable for storing any suitable alcoholic beverage, such as any suitable flavored alcoholic beverage. The container <NUM> generally includes a base <NUM>, sidewall <NUM> extending from the base <NUM>, a shoulder <NUM>, and a neck <NUM>, which extends to a finish portion (obscured by the closure <NUM> in <FIG>) of the container <NUM>. The finish defines an opening of the container <NUM>.

The container <NUM> can be made of any suitable material, such as mono-layer polyethylene terephthalate, or any other suitable polymeric material. The container <NUM> can have any suitable capacity for product, such as any suitable capacity from <NUM> oz. to <NUM> oz. Specific product capacities for the container <NUM> include <NUM> (<NUM> oz. ), <NUM> (<NUM>) oz. , <NUM> (<NUM> oz. ), and <NUM>. The finish of the container <NUM> can define an opening of any suitable diameter, such as any suitable diameter of <NUM>. , including diameters of <NUM>. , and <NUM>.

The closure <NUM> advantageously provides a carbon dioxide generating system for the container <NUM>, which extends the shelf life of product of the container <NUM>, such as carbonated soda drinks. After the container <NUM> is filled and capped with the closure <NUM>, the closure <NUM> slowly generates supplemental carbon dioxide for a period of time to offset the loss of carbon dioxide that escapes out through the container <NUM>, such as through the base <NUM>, sidewall <NUM>, and shoulder <NUM> of the container <NUM>. The carbon dioxide generating system of the closure <NUM>, which is described further herein, is particularly well suited for polyethylene terephthalate (PET) containers ranging from about <NUM> (<NUM> oz. ) to about <NUM> (<NUM> oz. ) in size due to the current shelf life of <NUM>-<NUM> weeks, at which time the amount of carbon dioxide within the container typically falls below acceptable consumer limits, and begins to affect product taste and quality requirements. This is in contrast to larger <NUM>-liter sized carbonated soda drink containers having a shelf life of <NUM>-<NUM> weeks. The present teachings advantageously increase the working shelf life of smaller size carbonated soda drink products by about twofold, so that carbonated soda drink fillers have more time to distribute and sell carbonated products before they expire. The present teachings advantageously increase the shelf life to <NUM>-<NUM> weeks for carbonated products stored within containers (such as container <NUM>) closed with the closure <NUM>, at which time only about a <NUM>% loss in carbon dioxide occurs, which is well within acceptable limits.

The closure <NUM> can be made of any suitable material, such as any suitable polymeric material or metallic material. Suitable polymeric materials include polypropylene, low-density polyethylene, and high-density polyethylene. The closure <NUM> can have any suitable diameter, such as any suitable diameter from <NUM>. , which includes <NUM>. , and <NUM>.

With reference to <FIG> and <FIG>, the closure <NUM> generally includes a base <NUM> and an annular wall <NUM> extending from the base <NUM>. Extending from an inner surface of the annular wall <NUM> are internal threads <NUM>, which are configured to couple with threads of the container <NUM> in order to secure the closure <NUM> to the container <NUM> and seal the container <NUM> closed. Also extending from the base <NUM> is a closure flange <NUM>. The closure flange <NUM> includes a distal surface <NUM> at an end of the closure flange <NUM> that is distal to the base <NUM>. The closure flange <NUM> further includes an outer surface <NUM>, which is opposite to the internal threads <NUM>. The outer surface <NUM> is configured to contact and seal against an inner surface of the finish portion of the container <NUM>. The closure flange <NUM> is generally an annular flange that defines a closure bore <NUM>. The closure bore <NUM> can be any suitable height and defined in any other suitable manner as well. For example, the closure bore <NUM> can be defined by a recess within the base <NUM>, or by any other suitable member extending from the base <NUM>.

Seated within the closure bore <NUM> is a carbon dioxide emitter <NUM>, and a release rate control layer <NUM>, which is arranged to control release of carbon dioxide from the carbon dioxide emitter <NUM> into the container <NUM> when the closure <NUM> is coupled to the container <NUM>, as explained further herein. The release rate control layer <NUM> can be overmolded onto the carbon dioxide emitter <NUM>, or arranged on the carbon dioxide emitter <NUM> in any other suitable manner. The release rate control layer <NUM> can be confined to within the closure bore <NUM>, or can extend out from within the closure bore <NUM>, such as to and/or across the distal surface <NUM> of the closure flange <NUM>. As shown in <FIG>, base <NUM> may also have a suitable sealing liner <NUM> attached to the inner surface of the base <NUM>. The carbon dioxide emitter <NUM> can be placed directly on the sealing liner <NUM> and overmolded with the control layer <NUM> to hermetically attach to the sealing liner <NUM>.

The carbon dioxide emitter <NUM> can be formed of any suitable blends of bicarbonate base as shown in the table of <FIG>, citric acid, and polyvinyl pyrrolidone (PVP). It is known that different types of acids can be combined to "control the reaction" under different temperature and storage condition to maximize shelf life extension. For example, relatively slower reaction kinetics driven by higher pKa acids, such as adipic acid, will trigger reaction at higher temperature while they are dormant in lower temperature; thus blends of acids will be able to control reaction kinetics under different temperature conditions as shown in <FIG>. The carbon dioxide emitter <NUM> can also be made of a material blend including bicarbonate, citric acid, and microcrystalline cellulose (MC). The carbon dioxide emitter <NUM> can be formed in any suitable manner, such as by direct compression or injection molding. The carbon dioxide emitter <NUM> can be formed of any suitable size and shape to fit within the closure bore <NUM>. For example and as illustrated, the carbon dioxide emitter <NUM> can be shaped as a disc or tablet that is sized to fit into the diameter and depth of the closure bore <NUM>. The carbon dioxide emitter <NUM> may further include any suitable dry lubricant, such as magnesium stearate. The basic reaction to generate carbon dioxide from the carbon dioxide emitter <NUM> is as follows: <MAT>.

The PVP and MC are humectants, which provide the carbon dioxide emitter <NUM> with an increased affinity to water. The BC can be any suitable bicarbonate, such as a bicarbonate selected from the family of sodium, potassium, etc. The BC can be provided in any suitable generating capacity, such as at 267cc's CO<NUM>/g, as shown in <FIG> shows the CO<NUM> generating capacity of additional bicarbonate compounds as well. <FIG> gives the wt% of CO<NUM> in various bicarbonates, the calculated cc[STP]/g produced from each bicarbonate, and includes comments on stability and food clearance. The stability and food clearance provide context with respect to why one would select a given compound. The BC can be provided at any suitable weight to provide the desired shelf-life extension independent of the diameter and depth of the carbon dioxide emitter <NUM>. The carbon dioxide emitter <NUM> can optionally include additives, such as an optical tracer, which can be used for quality control purposes. <FIG> and <FIG> include exemplary material compositions for the carbon dioxide emitter <NUM>, including the percentage of each ingredient.

With respect to <FIG> and <FIG>, a list of CO<NUM> generator formulations is provided, which include bicarbonate, citric acid, lubricant (magnesium stearate and stearic acid) and humectant (MCC and PVP). MCC can be extended to more modified cellulose types including HPC (hycroproxpropyl cellulose), HPMC (hycroproxpropyl methyl cellulose) etc. Calculations of CO<NUM> generation capacity of formulations is based on citric acid as limiting reagent.

<FIG> shows that the CO<NUM> generating capacity can be increased by increasing the tablet weight. The carbon dioxide emitter <NUM> can optionally be coated to help strengthen and prevent unwanted dust as the carbon dioxide emitter <NUM> is handled and inserted into the closure bore <NUM>. Suitable coating materials include Acrylate copolymers, Eudragit E, Cellulosic polymers, carboxymethylcellulose sodium, hydroxypropylcellulose, hydroxypropylmethylcellulose, methylcellulose, polyethyleneglycols, povidone, Methacrylic acid copolymer, Eudragit L and S® (anionic copolymers), cellulose acetate phthalate, hydraxypropyl methylcellulose phthalate, polyvinyl acetate phthalate, ethyl cellulose, Cellulose acetate phthalate, Polyvinyl acetate phthalate, and sugar. <FIG> shows that any amount of CO<NUM> (as required to increase the shelf-life) can be generated by adjusting the weight of acid and base in the formulation.

<FIG> illustrates the effect of tablet hardness, storage temperature, and control layer thickness on CO<NUM> lag time. Tablet hardness, storage temperature, control layer thickness, or their combinations can be used to tune CO<NUM> lag time.

<FIG> illustrates effect of control layer type and thickness, and storage temperature, on CO<NUM> lag time. A combination of control layer with various types and thicknesses and storage temperature can be used to tune CO<NUM> lag time.

<FIG> illustrates effect of acid mixture (citric and adipic acid) and temperature effect on formulation CO<NUM> capacity.

The release rate control layer <NUM> includes any suitable ethylene-vinyl acetate (EVA) copolymers, low-density polyethylene (LDPE), high density polyethylene (HDPE), polyvinyl acetate (PVA). LDPE provides relatively slower reaction times, and PVA provides relatively faster reaction times. Any suitable percentage of vinyl acetate (VA) can be included with the release rate control layer <NUM>, such as any suitable percentage of VA within commercially available ranges, which includes <NUM>%-<NUM>% VA.

An EVA composition of the release rate control layer <NUM> of from <NUM>% to <NUM>% VA determines material constant α = PCO2/PH2O. The material constant α controls permeability of the release rate control layer <NUM> to water vapor, and thus controls reactions at the carbon dioxide emitter <NUM> by controlling water vapor access. The material constant α also controls the release rate of carbon dioxide from the carbon dioxide emitter <NUM> into the container <NUM> by controlling permeability of the release rate control layer <NUM> to carbon dioxide.

The percentage of VA included with the release rate control layer <NUM>, and the thickness of the release rate control layer <NUM>, can be adjusted to control permeation of active carbon dioxide from the carbon dioxide emitter <NUM> and through the release rate control layer <NUM>, which has an effect on start time lag and release rate of carbon dioxide into the container <NUM>, as shown in <FIG> and <FIG>. The start time lag of carbon dioxide release is controlled by the thickness and material composition of the release rate control layer <NUM> using the following time lag equation: tL = L<NUM>/6D (where L = layer thickness, and D = diffusion constant of the selected EVA composition).

The release rate control layer <NUM> can be applied over the carbon dioxide emitter <NUM> in any suitable manner, such as by injection molding, overmolding, dual shot molding, compression molding, ultrasonic welding, heat sealing, induction sealing, solvent bonding, etc. The release rate control layer <NUM> is arranged in any suitable manner to encapsulate the carbon dioxide emitter <NUM> and provide a hermetic seal with the closure bore <NUM>, or any recess that the carbon dioxide emitter <NUM> may be seated within.

The release of CO<NUM> can only be achieved by constant moisture vapor exposure. The carbon dioxide emitter <NUM> is deactivated by removing the presence of moisture vapor such as when the closure is removed from a filled container. The carbon dioxide emitter can be reactivated when re-exposed to moisture vapor such as when the closure is re-applied to a partially filled container, as shown in <FIG>.

With reference to <FIG>, a method for providing the closure <NUM> so as to release carbon dioxide into the container <NUM> at a desired time and rate in order to extend the shelf life of carbonated products is illustrated at reference numeral <NUM>. With reference to block <NUM>, the target volume of the container <NUM> is selected, such as <NUM> (<NUM> oz. ), <NUM> (<NUM> oz. , etc. With reference to block <NUM>, the amount of carbon dioxide required to extend the shelf life of the container product, such as to <NUM>-<NUM> weeks with no more than a <NUM>% loss of carbon dioxide, is determined in any suitable manner, such as with any suitable lookup table and/or formula. <FIG> set forth carbon dioxide loss and generation curves for three different exemplary sized containers.

With reference to block <NUM>, the diameter of the carbon dioxide emitter <NUM> is determined based on the size of the area that the carbon dioxide emitter <NUM> is to be seated at, such as at the closure bore <NUM>. With reference to block <NUM>, based on the material compositions selected for the carbon dioxide emitter <NUM>, such as any of the compositions set forth in <FIG>, <FIG>, and <FIG>, the thickness of the carbon dioxide emitter disc <NUM> required to produce the required amount of carbon dioxide determined in block <NUM> is identified. With reference to block <NUM>, the carbon dioxide release lag time and release rate is determined based on the volume of the container <NUM>, the amount of carbon dioxide required as determined at block <NUM>, and the dimensions of the carbon dioxide emitter determined at block <NUM>. <FIG> set forth how to control carbon dioxide release lag time (start time) and release rate by changing the % EVA and thickness of the release rate control layer <NUM>.

With respect to <FIG>, CO<NUM> profiles with different tablet formulations are provided. CO<NUM> reading is lower than the experimental capacity of the formulation. This is due to the CO<NUM> outgress from the PET test bottle. The test was performed with tablets contained in <NUM> mils EVA <NUM>% sachet (in a PET bottle with <NUM> water) at room temperature.

With reference to block <NUM>, the carbon dioxide emitter <NUM> can be formed in any suitable manner, such as by direct compression or injection molding. With reference to block <NUM>, the formed carbon dioxide emitter <NUM> is inserted into the closure bore <NUM>. At block <NUM>, the percentage of vinyl acetate required for the release rate control layer <NUM> at a thickness of about <NUM> to <NUM>, or about <NUM>, for example, and at the determined diameter of the carbon dioxide emitter <NUM> is determined. At block <NUM>, the release rate control layer <NUM> is overmolded onto the carbon dioxide emitter <NUM>.

With reference to block <NUM>, the container <NUM>, or any other suitable container, is filled with product, such as carbonated product. The filled container <NUM> is then capped with the closure <NUM>. The closure <NUM> extends the shelf life of the carbonated product by offsetting carbon dioxide that is lost through the container <NUM> with supplemental carbon dioxide. Specifically, water vapor from the carbonated product permeates the release rate control layer <NUM> and enters the carbon dioxide emitter <NUM> to activate the bicarbonate (BC) of the carbon dioxide emitter <NUM>. The bicarbonate (BC) generates carbon dioxide, which permeates the release rate control layer <NUM> at a time and rate controlled by the release rate control layer <NUM>, in order to emit supplemental carbon dioxide into the container <NUM>.

<FIG> illustrates how CO<NUM> generation capacity of the carbon dioxide emitter <NUM> is affected by the bicarbonate to citric acid (BC/CA) stoichiometry ratio. Specifically, the plot of <FIG> shows that a BC/CA stoichiometry ratio between <NUM>-<NUM> is to be used in the formulation of the carbon dioxide emitter <NUM> to achieve high CO<NUM> capacity. Lower or higher stoichiometry ratio than <NUM>-<NUM> would provide lower CO<NUM> capacity.

The extent of protection shall be determined by the claims; the specification and the drawings shall be used to interpret the claims.

Claim 1:
A closure for a container (<NUM>), the closure (<NUM>) comprising:
a carbon dioxide emitter (<NUM>); and
a release rate control layer (<NUM>) configured to control release of carbon dioxide from the carbon dioxide emitter (<NUM>) into the container (<NUM>) when the closure (<NUM>) is coupled to the container (<NUM>);
wherein the carbon dioxide emitter (<NUM>) includes bicarbonate and citric acid;
characterized in that
the carbon dioxide emitter (<NUM>) further includes a humectant; wherein the humectant preferably includes at least one of polyvinyl pyrrolidone and microcrystalline cellulose that provide the carbon dioxide emitter (<NUM>) with an affinity to water; and
in that the carbon dioxide emitter (<NUM>) has a bicarbonate to citric acid stoichiometry ratio within the range of <NUM> to <NUM>.