Abstract:
A gasket for a bottle closure that regulates the diffusion of oxygen into the bottle is provided. In one example, the gasket includes a flexible substrate permeable to oxygen and a barrier film that is less permeable to oxygen than the substrate layer, where the combined structure has a light transmittance of between 0.5% and 10%. In some examples, the substrate includes a polymer layer and the film comprises a metal or non-metal film, where the film may be vapor deposited or sputtered onto the substrate. The metalized film layer may be deposited on the substrate to allow oxygen to diffuse there through at a rate of 1.5 cc/m 2 /day to 20 cc/m 2 /day, or 5 mg of oxygen to diffuse through over a period of 6 months to 8 years. The exemplary gasket or liner may further include a film that is perforated to create areas of differing oxygen transmission through the substrate and film structure.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority from U.S. Provisional application No. 61/315,510, filed Mar. 19, 2010, entitled OXYGEN REGULATION MECHANISM FOR A BEVERAGE GASKET, which is hereby incorporated by reference in its entirety and for all purposes. 
     
    
     BACKGROUND 
       [0002]    1. Field 
         [0003]    This application relates generally to bottle enclosures, and more specifically to gaskets for regulating oxygen transmission through a gasket and bottle enclosure. 
         [0004]    2. Related Art 
         [0005]    The elimination of oxygen ingress into perishable beverage containers has long been desired by industry. With some beverages, however, the complete elimination of oxygen transmission is not desirable. This is especially true in applications that involve maturation of the product over time, such as wine. While excess amounts of oxygen would spoil the wine via premature oxidation, the wine generally requires small amounts of oxygen in order to mature properly, and the lack of such oxygen can lead to the chemical reduction of the beverage over time. 
         [0006]    Alongside winemaking, wine bottling technology has evolved over the past several hundred years. The winemaking industry has relied on the use of cork, which allows small amounts of oxygen through, as a sealing medium for wine bottles in the wine aging process. Oxygen that permeates through a wine bottle&#39;s cork seal is “consumed” by the bottled wine through the formation of acetaldehyde, which serves as a linking molecule between monomers. This process helps to stabilize longer chains of tannins, resulting in a smoother tasting wine over time. 
         [0007]    The use of cork as a wine bottle sealing medium, however, suffers from several deficiencies. For one thing, the variability in natural cork bark, from which cork is made, results in variability in the rate of oxidation of wines in different bottles and consequently, variability in taste across bottles. In addition, cork contains a chemical known as 2,4,6 tricholoroanisole (TCA), a product of fungi that live in natural cork. When 2,4,6 TCA is released into wine, an unwelcome aroma is created. In small amounts, 2,4,6 TCA mutes the wine&#39;s aromatics but may completely ruin the wine in larger amounts. Excessive release of 2,4,6 TCA affects 2% to 5% of all corks. Furthermore, cork suffers from structural defects that include crumbling, breaking, and seepage, and requires the use of a tool (e.g., corkscrew) for removal from the wine bottle. Moreover, it is difficult to reseal a cork-sealed wine bottle without the use of additional devices. 
         [0008]    Several attempts have been made to introduce wine bottle closure products that aim to rectify some or all of the above deficiencies. These products include: synthetic cork, screw caps, Vino-Lock (a glass stopper with a silicone seal), Zork (a peel-off plastic closure), and others. None of these products, however, has eliminated all of the above deficiencies. For example, while synthetic corks can be made to provide a steady and customizable amount of oxygen flow into a wine bottle, a synthetic cork with an oxygen transfer rate similar to that of cork would use a material so hard that excessive force would be needed to remove it from the wine bottle neck. 
         [0009]    The most popular alternative, the screwcap, uses a gasket that contains high-barrier materials; most commonly a layer of tin foil or Poly-vinyl-di-chloride (commonly known as PVDC or Saran). The oxygen transmission rate of these materials, however, is too low to meet the oxygen requirements of most wines. 
         [0010]    A closure is desired that would admit moderate amounts of oxygen into the container, but do so in a predictable and selectable, or programmable, way. The amount of oxygen desired for a wine is dependent upon the style of that wine and its needs for oxygen in maturation, but for the theoretical average wine, it can be said that the wine will be in threat of developing oxidized characters by the time 5 ppm of oxygen has entered the bottle. It is then up to the winemaker to decide how long of a time period they would prefer for that bottle to absorb 5 ppm of oxygen. 
         [0011]    To match the current styles of wine, the desired amount of oxygen should be allowed into the container over a period of time ranging between 6 months to 8 years. A deciding factor in choosing the appropriate oxygen rate is the wine style and the winemaker&#39;s intention for how that wine develops in the bottle. For illustrative purposes, 5 ppm of oxygen over 6 months to 8 years in a standard 750 ml wine bottle equates to a transmission rate of approximately 1.5 ml/m 2 /day to 20 ml/m 2 /day. 
         [0012]    Several approaches have been suggested to achieve desirable rates of oxygen transmission rate in fluid containers; some have implied that the addition of multiple barrier properties of multiple layers of different materials can arrive at a barrier within the relevant range by summation. For example, U.S. Pat. No. 12/403,082 titled VENTED SCREWCAP CLOSURE WITH DIFFUSIVE MEMBRANE LINER, filed Mar. 12, 2009, the entire contents of which are incorporated herein by reference, describes closure and liner devices for regulating the oxygen through the perforation of liner layers to expose different amounts of surface area in subsequent layers, or to force the oxygen through a tortuous path. While these devices are functional, they may have a mild level of variance due to the delicate nature of aluminum and tin foils used for the closure housings can make them susceptible to physical defects which may significantly affect the performance of the liners. In addition, the perforations of such closure housings generally requires a delicate handling and manufacturing complexity. 
       BRIEF SUMMARY OF THE INVENTION 
       [0013]    According to one aspect of the present invention, a gasket for a bottle closure that regulates the diffusion of oxygen into the bottle is provided. In one example, the gasket includes a flexible substrate that is at least semi-permeable to oxygen and a barrier film that is less permeable to oxygen than the substrate layer, where the combined structure of the flexible substrate and the film disposed thereon has a light transmittance of between 0.5% and 10%. The structure may further be attached or disposed with an elastomeric liner layer. 
         [0014]    In some examples, the substrate includes a polymer layer and the film comprises a metal or non-metal film, where the film may be vapor deposited or sputtered onto the substrate. The film may be deposited on the substrate to allow oxygen to diffuse therethrough at a rate of 1.5 cc/m 2 /day to 20 cc/m 2 /day, or 5 mg of oxygen to diffuse therethrough over a period of 6 months to 8 years. 
         [0015]    The exemplary gasket or liner may further include a film that is perforated to create areas of differing oxygen transmission through the substrate and film structure. In other examples, the film may be deposited in a manner to create windows or areas of higher and lower oxygen transmission. 
         [0016]    According to another aspect of the present invention, a system for perforating a film layer for use in a beverage gasket is provided. In one example, the system includes a processor having a memory and a perforator, wherein the processor is operable to control the perforator to perforate a material having layer formed on a substrate layer in response to an optical density of the material. The perforation may be in response to a measured light transmission or optical density of the material to achieve a desired oxygen transmission rate. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    The present application can be best understood by reference to the following description taken in conjunction with the accompanying drawing figures, in which like parts may be referred to by like numerals. 
           [0018]      FIG. 1  illustrates a cross-sectional view of an exemplary bottle cap enclosure and liner disposed therewith. 
           [0019]      FIG. 2  illustrates an exploded view of an exemplary liner or gasket for a bottle cap enclosure; 
           [0020]      FIG. 3  illustrates an exemplary liner roll for manufacturing liners for a bottle clap enclosure; 
           [0021]      FIG. 4  illustrates a table of exemplary film materials and exemplary oxygen transmission rates and light transmission rates; 
           [0022]      FIGS. 5 and 6  illustrate schematically exemplary apparatuses for manufacturing liners for use with bottle cap enclosures; 
           [0023]      FIG. 7  illustrates a cross-sectional view of various exemplary perforated liners or gaskets for a bottle cap enclosure; and 
           [0024]      FIG. 8  illustrates an exemplary computing system. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0025]    The following description sets forth numerous specific configurations, parameters, and the like. It should be recognized, however, that such description is not intended as a limitation on the scope of the present invention, but is instead provided as a description of exemplary embodiments. 
         [0026]    According to one embodiment provided herein, a closure having a film (for example, comprising metal deposited to a polymer film substrate) is used to regulate the transmission of oxygen into the closure. In one example, the film is processed through control of the optical density (or transparency) of the film. In one example, the film comprises a metalized film. Metal of the metalized film can be applied to a substrate and/or the closure in a variety of suitable ways, including vapor deposition. The exemplary bottle closure may provide a closure that is relatively simple to manufacture and provides a discreet and selectable amount of oxygen permeation to the bottle contents. 
         [0027]    Metalized films have been developed to replace metal foils for a number of packaging products, such as potato chip bags and candy bars. Such metal foils are generally applied with the intent of excluding the maximum amount of oxygen practically possible. The benefit of these films is that they approach the oxygen-barrier properties of a foil, but are easier to use in manufacturing and can be made at a significantly lesser cost. The present art for these films fall into two categories: replacement of foils for food packaging where there is very little oxygen let through, or the shielding of materials from light penetration, such as use in reflective exterior windows, or welding shields. In the latter application, oxygen transmission is generally not a relevant metric. 
         [0028]    For many materials such as metals (e.g., aluminum, Tin, Zinc, Nickel, etc.) and non-metallic crystals (e.g., ceramics and glasses) deposited onto a polymer film, there is a correlation between the optical density of the film and its oxygen transmission characteristics. For example, the optical transparency of a coated film can be correlated and indexed to an expected oxygen transmission rate. Because of this, the production of a metalized film that meets the desired oxygen transmission levels for bottle contents, e.g., wine bottles, using existing technology and methods can be achieved. With the knowledge of the oxygen barrier properties of the substrate without the deposited material, the oxygen performance of the deposited film can be predicted by measuring an optical density thereof. 
         [0029]      FIG. 1  illustrates a cross-sectional view of an exemplary bottle cap enclosure  100  and liner  104  disposed therewith according to one example. As described in greater detail below, liner  104  may comprise a layer of metalized film with an optical density in the relevant range that allows the metalized film to perform (e.g., allow oxygen transmission) within a desired range for the bottle contents. The below descriptions will refer to a metalized film, but the same or similar structures can be used and produced with other non-metallic, oxygen-regulating materials as mentioned above. 
         [0030]    In one example, closure  100  may be constructed from metal such as aluminum or steel that are impermeable to atmospheric air, and contains one or more openings, or ventilation holes, through which atmospheric air can pass to reach liner  104 . In one embodiment, closure  100  is a screw cap closure for a wine bottle. It should be noted, however, that other embodiments of the present invention may include liners that are fitted within bottle cap closures other than screw cap closures and bottle cap closures for bottles other than wine bottles. 
         [0031]    According to one approach, liner  104  may comprise two or more layers that include at least one semi-permeable layer and at least one impermeable layer. Semi-permeable layers may be constructed from materials that are semi-permeable to oxygen such that oxygen can diffuse through the semi-permeable layers. An example of a material that is semi-permeable to oxygen is polyester. Material for semi-permeable layers may also be slightly elastic so that the semi-permeable layers may be compressed in the areas where the liner is sandwiched between the rim of the bottle below and the screw cap closure above, and further able to stretch when being forced on and/or into the opening of the bottle. This elasticity may fill any irregularities in the sealing surface and ensure a tight seal for the bottle. 
         [0032]    Various materials and designs of closure  100  and liner  104  are described, for example, in U.S. patent application Ser. No. 12/403,082 titled VENTED SCREWCAP CLOSURE WITH DIFFUSIVE MEMBRANE LINER, filed Mar. 12, 2009, the entire contents of which are incorporated herein by reference. 
         [0033]      FIG. 2  illustrates exploded views of two exemplary liners  104   e  and  104   c  in greater detail (which are also shown in  FIG. 7  and discussed below). Liner  104   e  includes a substrate film, substrate  106 , which may include one or more layers that are semi-permeable to oxygen. Exemplary barrier layers can be adhered to an elastomeric gasket layer  110  with the barrier layers oriented towards the bottle lip and the sealing surface of the container. 
         [0034]    Further, liner  104   e  includes a metallization layer  108 , which may be formed on substrate  106  through vapor deposition, sputtering, electrochemical deposition, or other suitable processes for fixing metallization layer  108  to substrate  106 . In some examples, metallization layer  108  may form a continuous layer on substrate  106 ; however, in other examples, holes or windows may be present in metallization layer  108  as a result of deposition (e.g., sputtering or a resist pattern) or from post etching or perforating. Additionally, metallization layer  108  may include non-metallic layers as described herein. 
         [0035]    Exemplary liner  140   c  is similar to  104   e,  however, in this example, metallization layer  108  is disposed between two substrate layers  106 . Substrate layers  106  may include the same or different materials, thicknesses, and so on. 
         [0036]    For substrate films such as polyester (PET) the degree of light transmission to create a barrier within desired oxygen transmission specifications generally desired for winemaking is between 20% and 0.5%. This degree of metallization will vary with the material due to the nature of the deposition of the metal during the metallization process but is still higher than the current art which aims for very little transmission of oxygen. 
         [0037]    For lower-barrier substrate films, such as polyethylene, the degree of metallization will generally be higher. The cause of this relationship stems from the nature of the deposition of the metal during metallization; for example, the film substrate is being randomly spattered by microscopic particles of metal which sometimes overlap and sometimes leave windows through the film.  FIG. 3  illustrates an example where of the structure with different sized windows across a roll. At one optical density  120  there are “windows”  112 , where oxygen can move through the barrier film at a rate that is characteristic of that film. Conversely, where the film has specs of adhered metal,  114  the transmission is effectively zero. The degree to which these windows occur in the metalized film generally dictates the transmission of light as well as the diffusion of oxygen through the film. By way of example, a film with a higher density of deposition such as  122  in  FIG. 3  will have lower oxygen transmission because its surface area under deposited material  118  is greater than  114  and the surface area of the windows  120  is smaller than that of  112 . This change in oxygen transmission can easily be detected optically. 
         [0038]    The description of this relationship can be expressed by the equation: 
         [0000]    
       
      
       M 
       OTR 
       *L 
       TX 
       =F 
       OTR  
      
     
         [0000]    where M OTR  is the base polymer&#39;s Oxygen Transmission Rate (“OTR”), L TX  is the % of light transmission (a similar measure of optical density) through the film and F OTR  is the resulting oxygen permeability of the manufactured film. 
         [0039]    This formula allows a closure manufacturer to spec a film and/or substrate that will provide the desired performance characteristics for a given beverage, container size, substrate film properties, desired oxygen transmission level, and so on. 
         [0040]      FIG. 4  relates the application of this formula to a table of several known oxygen barrier films and the level of metallization required to bring them to a similar OTR Level. For the purposes of illustration, one appreciates that some films are not acceptable because they do not allow adequate oxygen through by themselves. Other films require such a high level amount of metallization that very small variances in the amount of metallization will produce large changes in OTR. 
         [0041]    The current art has focused on material selection as well as regulation of the thickness of these and similar polymers to modify oxygen performance, and the addition of metallization has typically been applied in situations where the highest possible barrier is desired. 
         [0042]    One significant advantage to the approach described here is that of consistency. A base polymer that has moderate oxygen permeability can be metalized to a moderate extent to produce the desired result. In the example of OPET, as included in the table of  FIG. 4 , as much as 5% light transmission is needed for a desired OTR. In this embodiment, a small change in the degree of metallization will not produce a large change in the film&#39;s OTR—as it would if a material such as LDPE were used. In the application of such a liner to a product with a long shelf-life such as wine, this degree of consistency is important. The lack of consistency and the extended life expectation of products such as wine is generally the barrier to achieving a high-performance closure. This degree of consistency for products such as wine would be difficult if one were trying to regulate OTR through material thickness or metallization percentage alone. 
         [0043]    To further pursue consistency, one may take into account the typical case that within a roll of metalized film  116 , and between rolls of metalized film, there may be internal variations in the optical density, thickness of the substrate film, and so on (e.g., as shown in  FIG. 3 ). This is expected due to the nature of the film extrusion process as well as the metalizing process which is subject to variations at the beginning or end of a run, changes in roll speed, and the random nature of the deposition process itself. 
         [0044]    Another advantage of the indexing of oxygen transmission to the optical density of a metalized film is that optical density can be measured in real-time in a manufacturing environment using optical sensors. For example, using an optical sensor to detect optical density as a roll is fed into the lamination or die cutting system. In contrast, the alternative of measuring oxygen transmission directly requires long-duration, and generally destructive, testing of portions of the metalized film. 
         [0045]    This real-time ability gives a manufacturer an opportunity to adjust to or sort within variations within a film on the fly when this metalized film barrier is used to replace the perforated foil layer proposed by U.S. patent application Ser. No. 12/402,082, referenced above. For example, in one embodiment, the metalized film can be perforated to a greater or lesser extent, e.g., by a computer-controlled laser, based on the level of metallization detected in the material at that point. 
         [0046]    As illustrated in  FIG. 7 , and described in greater detail below, the perforated layers (e.g.,  106  and  108 ) can be laminated over a medium-barrier layer  106   b  to create a “windowing” effect that may effectively regulate the amount of area of the medium-barrier that is exposed. 
         [0047]    While oxygen will still come through the metalized film in direct correlation with its optical density, these windows  105   a  will provide areas of higher diffusion, and changes in the size of these windows will allow the system to adjust in real-time to any variances in the optical density of the metalized film. 
         [0048]    Such a system would allow variable oxygen transmission according to the following formula: 
         [0000]      ( F   OTR   *A   F )+( MB   OTR *(1− AF ))= P   OTR  
 
       Where: 
       [0049]    F OTR =The oxygen transmission rate of the high barrier layer;
 
MB OTR =The oxygen transmission rate of the medium barrier layer; and
 
A f =The % of the membrane surface area covered by the high barrier layer.
 
         [0050]      FIG. 5  illustrates schematically an exemplary apparatus for manufacturing liners for use with bottle cap enclosures. In this example, a roll of metalized film  210  is fed through an optical detector  230  and through a perforator apparatus  220 . The metalized film may include one or more substrate layers having at least one surface thereof metalized. For example, via a vapor deposition process a desired amount of metal on the substrate may have been achieved. 
         [0051]    The metalized film  210  passes through or by an optical detector, which may include a light or laser source  232  and a detector  230  for detecting optical transmission properties of the metalized film  210  as it passes. For example, optical detector  230  may operate with a light source having a known average wavelength (e.g., 550 nm), a laser tuned to a particular wavelength, or other means for passing light through the metalized film  210  to the optical detector  230 . Optical detector  230  may monitor the optical transmission properties of metalized film  210  in predetermined intervals or continuously. It may also be placed at representative locations or across the width of the web in a continuous array. 
         [0052]    The detected optical transmission properties may be communicated to processor  222  and/or perforator apparatus  220  along with information from a web speed sensor  234  for use in determining the degree, if any, that the film should be perforated by perforator apparatus  220 . For example, apparatus may include a laser or a hot needle array to create perforations through the entire film or the metallization layer may be selectively removed or thinned by use of select laser wavelengths, mechanical or chemical etching, or similar process). The amount of selective removal or thinning may be in response to the optical characteristics determined by optical detector  230 . 
         [0053]    After processing by perforator apparatus  220 , metalized film  210  may be again rolled or stored for further manufacturing. In other examples, metalized film  210  may further pass directly to an apparatus for forming enclosure liners and/or to bottling apparatus to be included as part of a finished bottle enclosure. 
         [0054]      FIG. 6  illustrates schematically another application of optical transmission based correction of variance in the manufacturing process. In this embodiment, the light is transmitted through a fully assembled and die cut liner. Since the other components of the liner are translucent or transparent, differences in optical density at this stage will still be predictive of OTR. 
         [0055]    In this embodiment the light source  240  may be pulsed like a strobe to maximize intensity of the transmitted light. The light readings from sensor  230  may be transmitted to a computer processor  222  which controls the operation of a mechanical sorting grid  260 . The sorting function will serve to use any variance within the product itself as an opportunity to create multiple levels of oxygen transmission, and allow the product to be sorted into different performance levels. 
         [0056]    These real-time methods of variance-checking and correction will allow for extremely consistent products to be constructed. This is of critical importance for long-term storage applications such as wine where a very small change in oxygen transmission can have large consequences over time. 
         [0057]      FIG. 7  illustrates several cross-sectional views of an exemplary perforated liner  104  for a bottle cap enclosure, one embodiment  104   a  which has been perforated, for example, by the systems of  FIG. 5  or  6 . As illustrated, a series of windows or openings  105   a  have been formed in metalized layers  108  by perforating through both layers. In this embodiment the openings  105   a  are formed completely through to the substrate  106   b,  whereas in embodiment  104   b  the windows are formed only through metal layer  108 . This difference in structure can be accomplished with short-wavelength lasers such as nd-YAG, fiber lasers, and similar. Further, the spacing between openings  105   a  and  105   b  may vary, depending, for example, on detected optical transmission properties and desired oxygen transmission rates. Those rates may be varied by altering either the size or the number of windows, or a combination of both. 
         [0058]    In still another embodiment  104   c  there are no downstream perforations of the metalized film and the oxygen regulation is provided by the optical density alone. 
         [0059]    In embodiment  104   a  there are two layers of substrate  106 ,  106   b —largely for the purpose of encapsulating the metalized layer and the perforations therein. This is necessary to protect the metalized layer from contact with the contents of the bottle, to guard against accidental over-penetration by the laser and to provide a more robust seal with the bottle. 
         [0060]    However, with the selective removal of metal from the substrate (or by selectively preventing its deposition in the first place as described above) it is possible to do away with the secondary substrate lamination and allow the construction of embodiments  104   d  and  104   e.  In these embodiments the metalized film is laminated to the elastomer  110  of the gasket directly. Allowing for a simpler structure and lower cost. 
         [0061]    By starting with a liner such as that detailed by  104   c  a range of products of different oxygen transmission rates can be created by programming in a minimum amount of perforations to increase the overall permeability. This makes fine tuning and customization of oxygen rates possible while starting from one common set of base materials. 
         [0062]      FIG. 8  depicts computing system  900  with a number of components that may be used to perform the above-described processes. For example, computing system  900  may be part of or in communication with one or more of a metallization system, perforator system, optical detector system, closure apparatus, and so on. The main system  902  includes a motherboard  904  having an input/output (“I/O”) section  906 , one or more central processing units (“CPU”)  908 , and a memory section  910 , which may have a flash memory card  912  related to it. The I/O section  906  is connected to a display  924 , a keyboard  914 , a disk storage unit  916 , and a media drive unit  918 . The media drive unit  918  can read/write a computer-readable medium  920 , which can contain programs  922  and/or data. 
         [0063]    At least some values based on the results of the above-described processes can be saved for subsequent use. Additionally, a computer-readable medium can be used to store (e.g., tangibly embody) one or more computer programs for performing any one of the above-described processes by means of a computer. The computer program may be written, for example, in a general-purpose programming language (e.g., Pascal, C, C++) or some specialized application-specific language. 
         [0064]    Although only certain exemplary embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. For example, aspects of embodiments disclosed above can be combined in other combinations to form additional embodiments. Accordingly, all such modifications are intended to be included within the scope of this invention.