WO2007147218A1

WO2007147218A1 - Closure with line having specified oxygen transmission rate

Info

Publication number: WO2007147218A1
Application number: PCT/AU2007/000877
Authority: WO
Inventors: David Carew
Original assignee: Amcor Limited
Priority date: 2006-06-23
Filing date: 2007-06-25
Publication date: 2007-12-27
Also published as: NZ574167A; AU2007262671B2; AU2007262671A1

Abstract

A ROTE closure for a wine bottle is disclosed. The closure is formed so that the closure, when positioned on and sealing the wine bottle, has a mean oxygen transmission rate ('OTR') level (n = > 10, where 'n' is a number of samples tested) of greater than 0.0005 ml/day and less than 0.003 ml/day.

Description

CLOSURE WITH LINE HAVING SPECIFIED OXYGENTRANSMISSIONRATE

The present invention relates to the field of closures, particularly, although by no means exclusively closures for wine bottles .

The present invention also relates to the packaging used in this field.

In particular, although by no means exclusively, the present invention relates to closures used on wine bottles and to bottles that are closed by such closures .

BACKGROUND

Wine is produced by the yeast fermentation of the juice of grapes and occasionally other fruits . As part of the control processes for the fermentation and handling of the wine, sulphur dioxide and/or analogues such as metabisulphite is often added to the wine for reasons including "the killing and growth inhibition of unwanted bacteria and yeast, the inhibition of phenoloxidase activity, the interaction with wine phenols in the competitive oxidation, the reaction of sulfite with peroxide, the binding of aldehydes and anthocyanin pigments and the delay of brown pigment development"¹.

Wine bottles have traditionally been closed using corks . Corks have been well accepted by consumers , but are known to have deficiencies relating to their variability, being a natural material. One aspect of this variability relates to variable oxygen permeation. Oxygen transmission is an issue as the oxygen reacts with some of the

¹ Boulton, R. B., V. L. Singleton, L. P. Bisson, R. E. Kunkee. 1999 Principles and practices of winemaking. Springer Science+Business Media Inc. pg 448 components to change the flavour profile of the wine. Excessive oxidation leads to the generation of undesirable flavours in the wine. Further deficiencies include the presence of undesirable odorous chemicals , for example 2,4, 6-Trichloroanisole (TCA) .

More recently there have been some alternative closures offered to the market.

The alternative closures include plastic corks that have less variability and low price, but on average have higher oxygen permeability than natural corks, and have an adverse reaction with flavour components in the wine . Overall the wine flavour is altered².

The Zork closures , described in International applications WO03068622 and WO04058586, are types of plastic closures that have different insertion mechanisms but the published gas barrier performances are similar to the plastic corks.

The alternative closures also include roll-on tamper evident (ROTE) closures. ROTE closures have a long history of use as closures for wine, but only in recent times have found strong commercial acceptance. The stated advantages of ROTE closure include minimal gas transmission, easy opening and reclosing, clear tamper evidence, elimination of malodours from the closure, and elimination of variability compared to natural corks . ROTE closures are sealed with an inserted liner comprising a foam polymer situated in contact with the closure body, to which is laminated a metallic layer, usually tin, which acts as a gas barrier, to which is further laminated a thin layer of a high gas barrier polymer, typically

² Godden, P. et al "Wine bottle closures: physical characteristics and effect on composition and sensory properties of a Semillon wine. 1. Performance up to 20 months post bottling". Australian J. of Grape and Wine Res., 7(2) 2001. polyvinylidene chloride (PVDC) . The PVDC acts as a contact seal against the surface of the glass , as a barrier to the contact of the wine to the tin, and has low absorption of flavour components from the wine .

ROTE closures comprise a cap and a skirt which are interconnected by frangible tamper evident ribs that are broken when the cap is removed from a bottle. The cap is typically screw threaded and can be repeatedly opened and closed as desired. When positioned on a bottle, the cap fits over a bottle finish and the skirt extends down a bottle neck.

To achieve the required sealing performance it is understood in the art that the proper placement of a ROTE closure onto glass packaging requires the application of a vertical load in capping of between 150 kg and 200 kg, with a vertical load specification of 170-180 kg being commonly quoted, to properly re-form the closure around the bottle finish. These very high top loads are required to achieve an acceptable seal between the closure and the bottle, especially considering the manufacturing imperfections in the top in the bottle where the seal is applied.

Table 1 below sets out details of recommended head pressures for commercially available 30 x 60 mm ROTE closures that support the above-mentioned traditional view . _J

Table 1 - Recommended head pressures for 30 x 60 mm ROTE closures .

The data for the Auscap, Global, and Newpak closures is soυrced from Stelzer, Appendix 3, and the data for the Amcor closure is sourced from the applicant.

With the significant increase in the use of ROTE closures for wine, qualitative evidence has been published which describes a dramatic increase in the sensory defect variously referred to as ^Λrubbery' , ^Λstruck flint' , ^Λreduced' , or ^Λrotten egg' . It is known that these types of odours are related to sulphur compounds , typically sulphides and disulphides, and these compounds have been reported as present in wines showing these defects . The common characteristic of these compounds is that the sulphur is found in a reduced oxidation state (S^2"") .

It has been postulated by the inventors and also by other parties that the generation of these reduced sulphur compounds is a result of the generation of a reducing environment in packaged wine . The generic term

"redox potential" is used to describe this aspect of an environment. Published authors (Peter Godden, Leigh Francis, John Field, Mark Gishen, Adrian Coulter, Peter Valente, Peter Hoj and Ella Robinson, "Wine Bottle Closures: physical characteristics and effect on composition and sensory properties of a Semillon wine 1. Performance up to 20 months post-bottling" Australian Journal of Wine and Grape research, VoI 7, Number 2, 2001; "Taming the Screw" Tyson Stelzer; Wine Press, Brisbane, Australia 2005, ISBN 0 9580628 4 6; pp 209-227) attribute the reducing environment to wine making practices and propose correction of this issue through modification of these wine making practices .

The inventors propose that the generation of a more reducing environment in packaged wine is an inevitable consequence of the use of sealing systems which greatly reduce the ingress of oxygen. A continuing ingress of oxygen will lead to a more oxidizing environment.

The traditional use of natural cork closures is known to provide a continuing if variable ingress of oxygen. Plastic corks also allow the ingress of oxygen, but in excessive levels resulting in oxidation of flavour components becoming a commercial issue.

The actual reducing environment inside the bottle will also depend on the wine making conditions, and the natural variability of the raw materials, including the varieties of grapes. Hence not all batches of wine will achieve the same redox potential in the bottled state, and hence the issue is not always apparent in the flavour of the wine .

It has also been found that the same reducing environment is sometimes found in bottles of wine closed with natural cork, but this is far less common and it is postulated that these reducing flavours may be masked by other flavour components produced by the imperfections of natural cork mentioned above .

It is further hypothesized by the inventors that the chemistry involved in the generation" of the reduced flavours involves the interaction of wine components within a reducing environment with free sulphur components, most probably the sulphur dioxide added as part of the normal wine making process for valid and continuing technical reasons . The implication of this hypothesis is that it would be extremely difficult to avoid resultant reduced flavours by changing wine making conditions or other treatments , except the elimination of sulphur dioxide from the process, which will lead to other issues .

Examination of texts on the electrochemistry of sulphur shows that a certain redox potential is required before the reduction of sulphur compounds to the sulphide form can occur and have a detrimental effect on the wine .

Clearly a generic reduction in the redox potential of wine due to the use of low permeability closures means a higher proportion of packaged wines will reach the critical redox potential mentioned above and undergo these undesirable reduction reactions .

Another effect to be considered is the aging of the bottled wine. While a lot of wine is intended to be drunk within a few years of bottling, some wine, which tends to be higher quality is also intended to be stored for a period of time ranging from one year to fifty years or upwards so that the flavours improve with age. This process is known as ^Λaging' or ^Λcellaring' . It is thought by some winemakers that the use of natural cork closures is important for aging as the small amount of oxygen passing through the cork helps in the generation of desirable flavours, possibly through the oxygen taking part in certain oxidation reactions that are important in the generation of desirable flavours .

"Aging in bottle then will permit slower reactions to continue and reactions requiring different conditions, particularly freedom from air contact and from escape of highly volatile substances. ^λΛ (Boulton, R. B., V. L. Singleton, L. F. Bisson, R. E. Kunkee. 1999 Principles and Practices of Winemaking. Springer Science+Business Media Inc. pg 383)

It is known in the art that sealing wine with cork leads to a generally acceptable outcome, both for wines intended to be consumed shortly after packaging and for wines where aging leads to desirable flavour generation .

It is hypothesized by the inventors that the reason for this is that natural cork, despite some of its disadvantages mentioned above, intrinsically has an acceptable oxygen transmission rate (OTR) for its intended function .

It is further hypothesized by the inventors that the normal OTR of natural cork is sufficient to avoid the generation of excessively reducing environments within the packaged product in the majority of cases, and leads to desirable aging of wine.

It is further hypothesized by the inventors that in some cases the natural variability of cork can lead to insufficient OTR and occasional bottles showing reduced environments and associated flavours.

There is little reliable published data on the OTR of natural cork. Measuring OTR of natural corks is deceptively difficult due to the way that OTR is normally measured. The normal measurement method (ref ASTM D-3985) measures the oxygen flow through the material to be measured with an oxygen containing atmosphere (generally air) on one side and an oxygen free atmosphere on the other side . The driving force for oxygen transmission is Brownian motion only. The experiment is defined as concluded when the OTR rate of change is less than 1% in 24 hours.

Natural cork has a significant content of free gas and consists of a large number of individual cells, each with a reasonable gas barrier to adjacent cells. For this reason the inventors have found through experiment that the measurement takes a very long time to reach a true equilibrium. In particular, the inventors do not regard a 1% change in 24 hours as being a sufficient indicator of equilibrium, and instead look for no long term changes in the indicated OTR figure from the instrument described in the ASTM over a period of at least 5 days .

Further, for the purpose of measuring OTR in a series of experiments, the inventors have modified the method as disclosed in the ASTM as follows, such description being clear to those skilled in the art of permeation measurement:

• Manufacture of mounting plates for packages , comprising metal plates, metal tubing mounted through the plates with soldered joints, and "Swagelok" or similar fittings .

• Removal of necks from bottles with an abrasive saw, to provide access to the underside of the closure, and also provide a surface flat to less than lmm for mounting to the mounting plate .

• Adhesion of the cut surface of the bottle to a plate with a cross-linked epoxy adhesive (Araldite K219 or equivalent) to provide a sealed closure/neck assembly with metal tubes for gas entry and exit from the "product" side .

• Provision of an atmosphere of 100% oxygen on the external surface of the closure by enclosure of the sample in an environment of flowing oxygen at 1 atmosphere, vented to atmosphere to avoid pressure build-up .

• Mounting the above assembly to the equipment described in the ASTM by manufacturers standard procedure . • Measurement of the apparent OTR periodically until the inventor's criteria for equilibrium is achieved.

• Removal of the closure/bottle sample and confirmation of background leakage levels by sealing the test plate with an impermeable mask such as a metal cup or glass jar.

Correction of the measured level of OTR for the use of 100% oxygen by accepted practice.

From application of the above modified method, it is clear that the use of less than an extended period of test leads to variable and over-stated OTR measurements.

Further, from the above, it is clear that the background leakage and thus reliability of the method is approximately 0.001 cc/sample/day (for convenience we refer hereinafter to permeability in units of mL/day) . As a sample is measured in 100% oxygen, the reliability of the method is thus approximately 0.0002 ml/day in air.

The applicant has measured the OTR of around 30 corks from a variety of sources using the above criteria for equilibrium. The OTR of approximately 90% of samples was in the range of 0.0005 to 0.001 ml/day when measured in air .. The remaining OTR measurements fell in the range 0.001 to 5.0 mL/day.

Table 2 set out below compares the measured data to a range of published OTR data for corks .

Table 2

Faculte d Oenologie de Bordeaux also noted that the age of the wine during cork OTR testing was critical, with the natural corks (stored horizontal) having a measured OTR of 0.025 to 0.045 mL/day during the first month, 0.0017 to 0.0061 ml/day between 2 and 12 months from bottling, before settling to the previously discussed equilibrium value of 0.0001 to 0.0023 ml/day. The

³ Godden, P. et al "Towards offering wine to the consumer in optimal condition - the wine, the closures and other packaging variables: A review of AWRO research examining the changes that occur in wine after bottling". Wine Industry Journal 20(4) 2005: 20.

⁴ Quoted in the report of Godden et al, with the 'technical cork' being available from Sabate USA and branded Altec

⁵ Cited in Mills, N. "Sealing themes and variations", Wine Industry J. 20(5) 2005:52 applicant postulates that this dependence on storage times may be partially caused by the oxygen contained in the cork before bottling. Oxygen in the headspace of the wine is consumed by the oxidation of the sulphur dioxide in the wine - this will create a partial oxygen vacuum in the wine which will draw out the oxygen in the cork, creating a false impression of the OTR of the cork. After 12 months it is possible that all of the oxygen initially contained in the cork has been consumed by the sulphur dioxide reaction, and the measured OTR of the cork is the true OTR of the cork

The dependence on cork-closed bottles on whether the bottles are lying down or standing up (ie whether the cork is wet by the wine or not) is noted by a number of authors , for example Mills . This is thought to affect the result of OTR measurements , for example the Mocon method in which the cork is dry is thought to be a poor indicator of wetted cork OTR⁶.

In summary, there is a large variation in the published OTR values , and range of OTR values , of corks . The applicant suggests that this is due to :

• The importance of allowing the measurement to reach equilibrium, as suggested by the Faculte d'Oenologie de Bordeaux.

• Whether the cork is wetted or not .

• The differences between technical and natural corks .

• Height of the corks . • Imperfections in sampling . Cork is a naturally variable material - in addition to this naturally variability , there will also be variability from the provenance of the cork , its length , or whether the sample is cracked . None of the studies shown above ,

⁶ R Gibson, "Variability in permeability of corks and closures" ' Presentation to American Society of Enology and Viticulture Science of Closures Seminar, June 2005 , found at : <www. scorpex. net/ASEVClosures2005RGibson . pdf > . including the applicants, have the large number of samples that would be necessary to truly characterise the OTR variability of cork, although the data of the applicants and Gibson (2005) both show the large variation in OTR data that might be seen from such a study.

NATURAL VARIABILITY OF CORK

Cork is a natural product, and hence the variation in OTR values is not surprising. Cork is the bark of the Cork Oak (βuerus suber) which is native to South Western Europe and North Western Africa. Cork oaks live for 150 - 250 years, with the first harvest after about 25 years, and subsequent harvests every 10 to 12 years. Being a long lasting and slow growing woody plant, breeding programs are slow, with in-vitro programs still in their infancy⁷. Hence most commercial cork production is from old stands⁸. This leads to significant genetic variability in even high rated commercial cork trees⁹.

The applicant postulates that due to the very long breeding and hence improvement cycles for oak cork, that the OTR and OTR variability levels for cork would have remained relatively constant over a long period of time. This is reinforced by the fact that cork consists mostly of suberin, a waxy substance found in some plants. The oxygen permeability through the cork is not dominated by via a physical transmission of the oxygen through

⁷ Gomez, A. et al "Androgenesis .- a tool for woody plant breeding" Recent Research Developments in Genetics and Breeding, VoI 1, Part II, 2004.

⁸ Eg see "Background for EU Project FAIR5-CT97-3480 "Optimisation of cork-oak seed management in support of community policies for reforestation and cork production", Background, found <http://www.divapra.unito.it/res/eu3480/index.htinl> at 28 May 2007, and

⁹ Aljorna, L. et al "Characterisation of Cork Oak (Quercus Suber L) genetic resources for tree improvement" , The Role of Biotechnology, Villa Gualino, Turin, Italy, 6-7 March 2005: 159 cracks in the cork (although excessive cracking can greatly increase the OTR of corks) but instead through a chemical diffusion of the oxygen through the suberin. This in turn is proportional to the diameter of the cork and its height (or length) , and inversely proportional to its density. Since the improvement programs of the cork oak is still in its infancy, the density of the cork should not have changed over the years . While we can only speculate on how the length of the cork has changed over the centuries, to the knowledge of the authors this has been relatively steady over the last 50 years, being a range from about 38 mm to 50 mm (1.5 inch to 2 inches) .

Since the OTR ranges of corks should have been relative stable over many years, it is likely the wine makers would have evolved their wine making techniques to work optimally with these OTR levels .

Nonetheless it is accepted in the art that some white wines, for example Sauvignon Blancs produced in the

Marlborough region of New Zealand, benefit from the extremely low OTR levels of ROTE closures. However, the wine making industry is still debating this issue for red wines .

Some authors¹⁰ have claimed the red wines continue to ^evolve' when bottled using ROTE closures ^primarily through is assumed to be anaerobic reactions . Some bottled wine may express "reductive" character in such an anaerobic environment, in contrast to the wine developing oxidised characters in a more aerobic environment, (but these reductive characteristics) are not thought to be commercially unacceptable'¹¹.

¹⁰ Hart, A. and Kleinig, A. "The role of oxygen in the ageing of bottled wine", Appendix 2, in Taming The Screw. Pg 211

¹¹ Ibid, page 227. However, the applicant queries whether winemakers , having carefully developed wine making methods for long stored wines such as premium red wine, would necessarily want to change the storage condition from a slightly aerobic environment to an anaerobic environment. In particular, premium winemakers would appreciate having the choice of a controlled and slightly aerobic environment so that they can continue to apply existing winemaking practices .

The applicant postulates that, based on the data and science discussed above, the optimal OTR level for premium red wine is comparable to the mean OTR levels of natural cork, which seems to between 0.001 and 0.002 ml/day.

It is also worth noting that ROTE closures have a measurable level of OTR . The Australian Wine Research Institute has published data¹² showing measured levels of OTR of 0 . 0002 to 0 . 0008 πiL/day , with a mean of 0 . 0005 . Similarly Faculte d' Oenologie de Bordeaux has published data showing an OTR rate of 0 . 0003 to 0 . 0007 mL/day . The applicants¹³ postulate that this high variability is due to the variability of the shape of the top edge of the bottle , which in turn would affect the mean path length between the headspace in the bottle and the unsealed environment .

It should also be noted that the applicant is not aware of published data showing a dependence of the OTR of screw cap closures on the orientation of the bottle , i . e the bottle does not have to be lying down for the closure to achieve the required OTR .

¹² Godden, P . et al "Towards offering wine to the consumer in optimal condition - the wine , the closures and other packaging variables : A review of AWRO research examining the changes that occur in wine after bottling" . Wine Industry Journal 20 (4 ) 2005 : 20 .

¹³ See also Stelzer, page 81 The small proportion of corks with a high OTR is thought to lead to the known incidence of wines to have ^oxidised' flavours.

THE CONSEQUENCES OF VARIABILITY OF OTR

The above data shows significant variation in the OTRs of corks and even ROTE closures . This in turn adds the variability of .wine making. It is clearly desirable for winemakers to have the option of being able to specify a controlled OTR rate for their closures .

One option for this is synthetic closures (plastic corks) .

Data published for the OTR of synthetic closures set out below in Table 3 shows a narrow variability in the OTR values of these closures .

Table 3

http : //www. nomacorc . com/assets/WOMACORCRCLASSIC .pdf

This suggests that synthetic closures have a narrow variability.

However, it is known in the art that synthetic closures lead to excessive oxidation of wine (Godden, 2005) , and are not the solution for premium wines.

A better solution would be based on ROTE closures, since these offer improved convenience to the consumer (no cork-screw required, recloseable) .

Nonetheless the synthetic data is valuable because it suggests an upper limit for the preferrer OTR of a wine closure, namely of about 0.002 to 0.003 ml/day, based on all of the data given above .

OTHER BREATHABLE SCREWCAP CLOSURES

US 5,730,306 to Costa et al discloses a multilayer venting liner inside a screw cap closure where ventilation is assisted by channels in the top layer of the liner, holes in parts of one of the layers , and a gas permeable polyolefin in the bottom layer which is in contact with the top of the closure. The closure appears to be a standard flat plastic closure. Air is vented from the container firstly through the 0.004 to 0.005 inch (0.1 to 0.12 mm) gas permeable bottom liner , and though the holes (or body) of the top liner, along the channels cut

http : //www.pmmi . org/ms/peconf/wll .pdf in the top liner, and finally past the screw threads between the closure and the container .

However, the resulting OTR of this closure would be much greater than acceptable for closing premium red wine . This would be caused not by the holes or channels in the top layers of the liner, but instead by the rate limiting step in the oxygen transfer, namely the gas permeable polyolefin. A thickness of only 0.1 to 0.12 mm for the permeable polyolefin would lead to a much thick much higher ROTE than would be acceptable for premium wine .

JP 2001/072097 to Kunihiko discloses a cork inside a screw closure. This too would be unsuitable for our objectives, as it would suffer from the natural variability in the OTR levels of cork closures .

US 3,951,293 to Schulz discloses an unsintered tetrafluoroethylene liner with a fibrillated structure of a thickness of 0.1 to 0.3 mm and a ^λdensity' of less than 1.4 (the units for density were not given, but we_. have assumed that the inventor meant a specific gravity of 1.4, i.e. 1400 kg/m3) . There is also a hole in the top of the closure to assist ventilation. Again this would have an unacceptably high OTR for premium wine, as the as the minimum resistance to oxygen transfer would be the thickness of the liner, which due to its fibrillated structure would have a low gas barrier and hence high OTR.

WO 1997/02994 to Vakharia discloses a closure with has a small internal gas permeable membrane to assist with ventilation. The preferred membrane listed is a porous polytetrafluoroethylene (PTFE) , especially a micro- porous sheet which has a microstructure of nodes connected with fibrils. The preferred porosity is a ^λGurley number' of 600, or 600 seconds per 100 ml of air. This equates to 1.4 mis/day, or significantly above the required level of less than 0.003 ml/day.

WO 2007/25334 to Balog discloses a concept of a ROTE screw cap with a permeable liner (cork or plastic, paper etc) and a hole in the top of the closure . In another embodiment a liner is used to separate the cork from the wine, therefore preventing TCA contamination of the cork .

None of the embodiments of Balog would provide an acceptably low OTR for premium wine . The drawings showing the cork embodiment illustrate a piece of cork of about 25 % of the exterior diameter of the closure, which equate to a height of about 6 mm for a typical 25 mm ROTE closure. As previously discussed, the OTR of a cork is inversely proportional to its length, and cork lengths are typically between 38 and 50 mm long. Hence the ROTE of this closure would be about 6.3 to 8.3 time greater than the typical ROTE of a cork, which would likely to be unacceptable in practice for reasons discussed above.

Other embodiments of the Balog invention discuss ^Λbreathable plastic material, polymer plastic, wax coated paper or cardboard' , there is no specific mention of the required permeabilities of these materials . Since the breathable materials ventilate to the atmosphere via a vent in the top of the closure , i.e. in a position where these materials are not under compressive pressure as is seen with traditional ROTE closures, we can predict the

ROTE levels of the closure will be much greater than acceptable for premium red wines .

INVENTION

The present invention provides a ROTE closure for a wine bottle that is formed so that the closure, when positioned on and sealing the wine bottle, has a mean oxygen transmission rate ("OTR") level (n = > 10, where ^λΛn" is a number of samples tested) of greater than 0.0005 ml/day and less than 0.003 ml/day.

Preferably the mean OTR level is greater than 0.0006 ml/day.

More preferably the mean OTR level is greater than 0.001 ml/day.

Even more preferably the mean OTR level is greater than 0.0015 ml/day.

Even more preferably the mean OTR level is greater than 0.002 ml/day.

Preferably there is a variation in OTR of less than 20% between samples tested.

The term "variation" as used herein is defined as the one sigma variation (~68.3%) of the data, or in other words the range of values between the mean measured value less the standard deviation of the data, and the mean value plus one standard deviation of the data. At least 10 samples need to be tested for a meaningful variation figure to be collected. Also the closures need to be tested in a dry state, i.e. either with a closed bottle in a vertical position or as a stand-alone test of a closure. While the applicant appreciates the effect that testing a closed bottle in a horizontal position may have on the results , they also postulate that in practice most filled bottles of wine will be stored in a vertical position, and hence testing in a vertical position is appropriate.

Preferably the OTR variation between samples tested is less than 15% . More preferably the OTR variation between samples tested is less than 10%.

More preferably the OTR variation between samples tested is less than 5% .

Preferably the closure comprises an internal liner that has a contact surface that, in use, is exposed to direct contact with wine in a wine bottle.

Preferably the contact surface is formed from a material or materials that do not affect the flavour components contained within the wine .

The internal liner may comprise a single layer of one material only, a single layer of a plurality of materials, multiple layers of one material, or multiple layers of different materials .

Preferably the internal liner does not include a metallic layer so that oxygen permeability is controlled entirely by the contact layer .

Preferably the internal liner is formed from any one or more of a range of materials that have different oxygen diffusion rates so that a wine maker can select closures having OTR levels suitable for different wine varieties, different wine making processes, and different options for storing wine.

The internal liner may be made from a range of materials including, but not limited to aromatic polyesters and polyester copolymers, aliphatic polyesters and copolymers , polyamide polymers and copolymers , and polybutylene terephthalate (sometimes known as PBT) . The closure may comprise an outer shell which is preferably an aluminium outer shell .

In that event, preferably the internal liner comprises one or more than one layer of a material that is selected to prevent interaction of the wine and the outer shell of the closure. This layer or layers may comprise polymers , metal foils , combinations thereof , or other materials suitable for this function.

The internal liner may comprise one or more than one layer of a material that is selected to provide compressibility between the shell of the closure and the wine bottle. This layer or layers may comprise paperboard, polymer foam, solid polymer, rubber, and other suitable materials .

According to the present invention there is provided an assembly of a wine bottle that contains wine and the above-described closure that closes the wine bottle and seals the wine in the wine bottle .

Preferably the wine bottle/closure assembly is formed so that there is a smooth sealing surface between the bottle and the contact surface of the closure.

Preferably the wine bottle/closure assembly is formed so that there is a minimum contact length (for a line originating at the axis of the bottom and going radially outwards) between the bottle and the contact surface of the closure of at least 2 mm, where "contact length" is defined herein as the length of the liner in intimate contact with the surface of the bottle, as measured from a cross-sections cut through the axis of a bottle and closure assembly.

The present invention is described further with reference to the accompanying drawings , of which :

Figure 1 is a partially cut-away side view of one embodiment of a ROTE closure in accordance with the present invention; and

Figure 2 is longitudinal cross-section of the closure shown in Figure 1.

The ROTE closure 3 shown in Figures 1 and 2 is a conventional closure in terms of the basic shape of the outer aluminium shell 5 shown in the Figure .

The ROTE closure 3 is characterised by by the internal liner 7.

Specifically, the internal liner 7 is formed so that the closure, when positioned on and sealing a wine bottle, has a mean OTR level (n = > 10, where ^λλn" is a number of samples tested) of greater than 0.001 ml/day and less than 0.003 ml/day.

In addition, the internal liner 7 is formed so that the there is a variation in OTR of less than 20% between samples tested.

The internal liner 7 comprises the following layers, a top layer 9 of expanded polyethylene, a paper layer 11, a tin layer 13, and a lower layer 15 of PVDC that has a lower surface 17 that defines a contact surface of the liner 7.

EXAMPLE

The OTR levels of two developmental wine bottle closures, consisting of ROTE closures having an internal liner made from different materials and applied to Amcor glass bottles, were measured.

The internal liner materials used comprised an ethylvinyl acetate (EVA) liner and a cork wadding.

Oxygen permeability evaluation was carried out by the applicant.

Sample Identification

There were two samples tested, each in duplicate, namely:

• ROTE closure fitted with EVA liner applied to a glass finish (Sample A and Sample B) ; and • ROTE closure fitted with a cork wad applied to glass finish (Sample C and Sample D) .

Evaluation

The closures on the glass finishes were cut from wine bottle necks prior to preparation for mounting and gluing onto Oxtran instrument package fittings .

The samples were conditioned in air (23°C, 50% RH, 21% 02), up to approx. 2.5 weeks to establish equilibrium, and tested by the Mocon instrument method using Oxtran 702 instrumentation.

Results/Discussion

Table 3 lists the oxygen transmission rate results for the ROTE wine closures fitted with experimental liner seals applied to glass : two samples with EVA liner and two samples with cork wadding liners . Table 3 : OTR of ROTE Wine Closures with Experimental Liner Seals

The results in Table 1 show that the measured OTR for the EVA liner was within the target levels of greater than 0.001 and less than 0.003 ml/day.

In addition, results in Table 1 show that the measured OTR for the EVA liner had an OTR variability

(between samples) of less than 20% of the OTR values of the samples .

While the OTR values were higher than ideal, this suggests a method for selecting materials for lower target OTR values, namely by comparing their intrinsic oxygen diffusion rates to the oxygen diffusion rates of the EVA material used in this experiment (or to other materials for which comparable OTR data is available) .

The closures with the cork liner had unacceptably high OTR levels, with periodic testing during the 18 day sample conditioning period revealing no change to OTR values . Examination of cross section of samples showed that under the tight compression these samples that the cork was starting to split, and this would explain these high OTR levels .

It is also important that the wine bottle be selected so that the top of a glass wine bottle is smooth, Examination of samples by cutting a cross-section through the centre of a bottle and closure assembly showed that the top of the glass had a smooth radius, and this allows the padding material to have a long contact path to the edge of the bottle . This in turn will ensure a good seal between the edge of the liner and the glass, which will mean that OTR will be controlled by the careful selection of the liner material.

Claims

1. A ROTE closure for a wine bottle that is formed so that the closure, when positioned on and sealing the wine bottle, has a mean oxygen transmission rate (^λΛOTR") level (n = > 10, where "n" is a number of samples tested) of greater than 0.0005 ml/day and less than 0.003 ml/day.

2. The closure defined in claim 1 wherein the mean OTR level is greater than 0.001 ml/day.

3. The closure defined in claim 1 wherein the mean OTR level is greater than 0.0015 ml/day.

4. The closure defined in claim 1 wherein the mean OTR level is greater than 0.002 ml/day.

5. The closure defined in any one of the preceding claims wherein there is a one-sigma variation in OTR of less than 20% between samples tested.

6. The closure defined in any one of the preceding claims wherein there is a one-sigma variation in OTR of less than 15% between samples tested.

7. The closure defined in any one of the preceding claims wherein there is a one-sigma variation in OTR of less than 10% between samples tested.

8. The closure defined in any one of the preceding claims comprises an internal liner that has a contact surface that, in use, is exposed to direct contact with wine in a wine bottle .

9. The closure defined in claim 8 wherein the contact surface is formed from a material or materials that do not affect the flavour components contained within the wine .

10. The closure defined in claim 8 or claim 9 wherein the internal liner comprises a single layer of one material only, a single layer of a plurality of materials, multiple layers of one material , or multiple layers of different materials .

11. The closure defined in any one of claims 8 to claim 10 wherein the internal liner does not include a metallic layer so that oxygen permeability is controlled entirely by the internal liner .

12. The closure defined in any one of claims 8 to 11 wherein the internal liner is formed from any one or more of a range of materials that have different oxygen diffusion rates so that a wine maker can select closures having OTR levels suitable for different wine varieties, different wine making processes, and different options for storing wine.

13. The closure defined in any one of claims 8 to 12 wherein the internal liner is made from any one or more of the following materials : aromatic polyesters and polyester copolymers, aliphatic polyesters and copolymers, polyamide polymers and copolymers , and polybutylene terephthalate .

14. The closure defined in any one of the preceding claims comprises an outer shell of a rigid material .

15. The closure defined in claim 14 wherein the shell is made from aluminium.

16. The closure defined in claim 14 or claim 15 wherein the internal liner comprises one or more than one layer of a material that is selected to prevent interaction of the wine and the outer shell of the closure .

17. The closure defined in any one of claims 14 to 16 comprises one or more than one layer of a material that is selected to provide compressibility between the shell of the closure and the wine bottle .

18. A wine bottle that contains wine and the closure defined in any one of the preceding claims that closes the wine bottle and seals the wine in the wine bottle.

19. The wine bottle/closure assembly defined in claim

18 formed so that there is a smooth sealing surface between the bottle and the contact surface of the closure .

20. The wine bottle/closure assembly defined in claim

19 formed so that there is a minimum contact length (for a line originating at the axis of the bottom and going radially outwards) between the bottle and the contact layer of the closure of at least 2 mm.