The present application relates in general to methods controlling oxygen ingress in cap closures. In particular, the present application is directed to methods controlling oxygen transmission in cap liners.
Most wines exhibit a chemical oxygen demand required for the proper development of flavors, mouth feel and aromas. This development is termed “wine maturation”. A cap closure that allows the correct amount of oxygen into a wine bottle will promote wine maturation at an ideal rate, otherwise referred to as aging. If a cap closure has no oxygen barrier, too much oxygen will cause the wine to oxidize rapidly and shorten its shelf life. It is commonly known within the wine industry that white wines are much more sensitive to oxygen while red wines are generally more tolerant of exposure to oxygen. It is generally accepted that the proper amount of oxygen entering the wine at a proper rate through the closure will have a beneficial effect on wine quality.
The traditional closure for wine is the bark of the Quercus Suber, commonly known as cork oak. The oxygen transmission rate (OTR) of a premium natural cork is considered by many winemakers to be the gold standard. Premium wines using such corks are normally stored inverted or laid on their side. Storing wine in this manner reduces the OTR by keeping the cork wet, thus enhancing its sealing capabilities.
In the current wine industry, aluminum screw-cap closures have become a popular alternative to cork closures due to their low cost and predictable performance. The crucial sealing performance of a cap is controlled to a large extent by its liner component. Cap liners are required to seal sufficiently to prevent the beverage from leaking out of the package. They are also crucial for controlling the transmission of oxygen from the air outside the package into the product while retaining volatile flavor molecules in the beverage. Liner types have traditionally been chosen by cap manufacturers (e.g. G3), with a focus on ease of use, performance and price. It is commonly known in the cap closure industry that changing materials within the cap liner laminate structure can vary the OTR of the liner. However, it is not commonly known how to precisely select a combination of materials and their thicknesses to obtain a desired OTR over a range of OTR.
There are two major cut-disk cap liner technologies that dominate the cap liner industry (e.g. cap liners manufactured by MEYER SEALS), those containing SARANEX (a polyvinylidene chloride (PVDC)/polyethylene (PE) laminate that provides barrier protection) as an oxygen barrier and those utilizing a combination of SARANEX with either tin or aluminum foil as the oxygen barrier. The OTR of these two cap liner designs are uniform at their respective values, the foil-SARANEX being much lower than the SARANEX alone.
The SARANEX layer is typically thin, ranging from 1.0 to 2.0 mils. SARANEX itself is normally a five layer laminate, the outermost layers being low-density polyethylene (LDPE) film with adhesive layers (e.g. ethylene-vinyl acetate (EVA)) or a similar tie-layer polymer between the LDPE and the PVDC. The PVDC is the oxygen barrier component of SARANEX. Most of the total thickness of the SARANEX film is due to the layers of LDPE and adhesive. The LDPE and the adhesive layers have very high OTR relative to PVDC and metal foils. The SARANEX cap liner is considered by some to allow too much oxygen into the wine, leading to a decreased shelf-life. The foil-SARANEX cap liner is known to allow almost no oxygen into the wine bottle, which can cause anaerobic conditions resulting in reduced or sulfidic aromas. Therefore, some in the wine industry believe that foil-SARANEX liners allow in too little oxygen. OTR tests of inverted natural premium Flor grade corks using the OX-TRAN (a system for oxygen transmission rate testing) system from MOCON (a provider for oxygen permeation detection instruments) determined that their OTR values were between those of SARANEX and foil-SARANEX cap liners.
There are currently no commercial cap liners for wine screw caps that provide OTR values close to that of a premium inverted natural bark cork. One prior attempt to create this range of OTR values was made by producing liners using different thickness of ethylene vinyl alcohol (EVOH) in place of the SARANEX barrier. However, the OTR of three thicknesses of EVOH were virtually identical to each other and very close to the OTR of a SARANEX cap liner. Another prior attempt was made using perforated metalized polymer, which resulted in unacceptable variability in OTR values.
Another prior attempt to achieve the desired OTR included applying various perforation schemes through tin foil and then using the perforated foil to create a laminate liner similar to a foil-SARANEX liner. However, this produced neither the desired control of OTR, nor an OTR close to that of a wine package finished with a premium natural bark cork. The perforations in the foil, which may be known as the primary barrier, did not control the OTR. The OTR values of this configuration were similar to that of a foil-SARANX liner without perforations in the tin foil.
Systems and methods for controlling oxygen ingress in cap closures are herein disclosed. According to one embodiment, the current apparatus includes a cap and a cap liner. The cap liner includes a primary oxygen barrier layer and a first diffusive layer. A first side of the first diffusive layer is adjacent to a first side of the primary oxygen barrier layer. A second side of the first diffusive layer contacts a lip-sealing surface of a bottle. The oxygen transmission rate of the cap liner is controlled by varying a thickness of the first diffusive layer,
The above and other preferred features, including various novel details of implementation and combination of events, will now be more particularly described with reference to the accompanying figures and pointed out in the claims. It will be understood that the particular methods described herein are shown by way of illustration only and not as limitations. As will be understood by those skilled in the art, the principles and features described herein may be employed in various and numerous embodiments without departing from the scope of the invention.
The accompanying figures, which are included as part of the present specification, illustrate the presently preferred embodiments of the present invention and together with the general description given above and the detailed description of the preferred embodiments given below serve to explain and teach the principles of the present invention.
a) illustrates an exemplary plot of a factor effect in a model for OTR control, according to one embodiment.
b) illustrates an exemplary plot of a factor effect in a model for OTR control, according to one embodiment.
a) illustrates an exemplary plot of the effect of the thickness of highly diffusive layers on OTR, according to one embodiment.
b) illustrates an exemplary plot of the effect of thickness of highly diffusive layers on OTR, according to one embodiment.
c) illustrates an exemplary plot of the effect of different materials on OTR, according to one embodiment.
It should be noted that the figures are not necessarily drawn to scale and are only intended to facilitate the description of the various embodiments described herein. The figures do not describe every aspect of the teachings described herein and do not limit the scope of the claims.
A method for controlling oxygen ingress in cap closures is disclosed. According to one embodiment, the current apparatus includes a cap and a cap liner. The cap liner includes a primary oxygen barrier layer and a first diffusive layer. A first side of the first diffusive layer is adjacent to a first side of the primary oxygen barrier layer. A second side of the first diffusive layer contacts a lip-sealing surface of a bottle. The oxygen transmission rate of the cap liner is controlled by varying a thickness of the first diffusive layer.
The present disclosure describes a cap liner design that delivers OTR including a range of OTR between the OTR of SARANEX and foil-SARANEX liners, and an extended range of higher OTR. This allows the creation of custom OTR for cap closures. The present cap liner design provides the OTR of a premium bark cork, according to one embodiment. The present cap liner design provides the OTR of synthetic cork, according to another embodiment. The OTR of synthetic cork includes 0.001 cc O2/cap/day.
Referring to
The path for the majority of the oxygen diffusion in an aluminum cap is through the liner's edge. Therefore, oxygen is entering the films in the liner through their edge and moves past the lip-sealing surface of the bottle. Oxygen then moves into the headspace of the bottle in a direction perpendicular to the flat surfaces of the liner. The diffusion of gases is proportional to the surface area of edge material exposed to air. The OTR increases with increasing thickness of the highly diffusive layers as more surface area is exposed to air.
The OTR of materials measured in the form of flat sheets is different from the OTR of the same material when inserted into an aluminum cap and secured on a bottle, The normal direction of gas diffusion in a flat sheet is perpendicular to the surface of the sheet. However, the OTR of a liner inside an aluminum cap is primarily controlled by gas diffusion that is perpendicular to the liner's edge.
According to one embodiment, the effect of different SARANEX films and the effect of different thicknesses of highly diffusive EVA adhesive films placed at two locations in the cap liner on OTR were evaluated. Referring to
a)-6(c) illustrate the effect of different SARANEX films and the effect of different thicknesses of highly diffusive EVA adhesive films placed at two locations in the cap liner on OTR according to the exemplary cap liner in
According to one embodiment, the effects of different thicknesses of highly diffusive films between a PVDC layer and the bottle finish on OTR are evaluated. Referring to
According to one embodiment, the effects of different thickness of highly diffusive films between a tin foil layer and the bottle finish on OTR are evaluated. Referring to
According to one embodiment, the effect of different thickness of highly diffusive films between semi-permeable Polyester (PET) film and the bottle finish on OTR are evaluated. Referring to
According to one embodiment, the effect of different thickness of highly diffusive films between a vacuum deposition metalized layer and the bottle finish on OTR are evaluated. Referring to
According to one embodiment, the effect of different thickness of highly diffusive films between a vacuum deposition metalized layer and the bottle finish on OTR are evaluated. Referring to
According to one embodiment, the present method is used for plastic cap liners. As there is additional diffusion of oxygen through the shell of the plastic cap, adjustments to the model may be necessary.
The above example embodiments have been described hereinabove to illustrate possible embodiments for controlling oxygen transmission rate of cap liners. Various modifications to and departures from the disclosed example embodiments will occur to those having ordinary skill in the art. The subject matter that is intended to be within the spirit of this disclosure is set forth in the following claims.
The present application claims the benefit of and priority to U.S. Provisional Application Ser. No. 61/579,611, entitled “Method for Controlling Oxygen Ingress in Aluminum Cap Closure”, filed on Dec. 22, 2011, and is hereby incorporated by reference.
Number | Date | Country | |
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61579611 | Dec 2011 | US |