EP2533957B1 - Treatment of natural cork stoppers and stoppers obtained by said treatment - Google Patents

Description

FIELD OF THE INVENTION

The invention relates to the field of corking bottles of alcoholic and spirits wines using natural or technical cork stoppers, more specifically a treatment of natural cork stoppers in order to eliminate their disadvantages.

STATE OF THE ART

The nature of cork, natural product perfectly suited to the field of corking, can cause disadvantages, particularly because of its heterogeneity and the presence of harmful molecules - typically haloanisoles and halophenols - that can alter the taste of bottled products. As a result, there are no two identical plugs.

We know natural cork and the different treatments to obtain corks. First of all, in order to obtain so-called natural plugs, the plugs are subjected to washing with very hot water to remove small waste and particles of cork or dust, insects, etc. In order to obtain so-called treated plugs, a second superheated steam treatment is generally applied to natural plugs to reduce the content of harmful molecules and reduce the risk of having bottles that are unfit for consumption because they have a "corky taste", expression generally used to designate an unacceptable organoleptic alteration of the bottled liquid due to contamination by the plug. Such a cork taste can be detected from a very low harmful molecule concentration threshold of 2 ng / l (nanograms per liter).

To limit cork contamination, some cork manufacturers use oxygen peroxide H ₂ O ₂ , sulfamic acid or metabisulphite acid, which also has the effect of bleaching cork on the surface. Generally, the treatment of the stoppers ends with the application on the plugs of slippery agents necessary for the automation of capping operations and to facilitate the extraction of the plug during the first opening of a bottle.

The so-called clogging treatment is also known in which a mixture of waxes and cork dust is applied to the stopper so as to obtain so-called "clogged" stoppers in order to be able to use a cork which is also rich in cracks. Other heavy treatments have been developed to try to eliminate the harmful molecules, the presence of harmful molecules remaining one of the concerns bottlers, bottlers and consumers.

The so-called critical CO ₂ process is known which makes it possible to obtain cork stoppers with a low content of harmful molecules. But this process says the CO ₂ critical only treat cork flour, not complete stoppers. This therefore requires to perform reconstructions of corks using glues or binders. In this case, we can no longer speak of natural cork stoppers, but of technical or synthetic corks, since they contain at least as much gluing material as cork. However, even in the case of treatment with critical CO ₂ , there is still a significant residual rate of defects, about 1% of bottles with a taste of cork.

There are also known treatments by superheated steam or even microwaves to reduce the content of the plugs into harmful molecules. In this case, the rate of defects related to the cork taste is of the order of 3%.

All these treatments, which make the defect rate fall below 5%, require however very heavy and expensive specific equipment.

Globally, about 18 billion bottles of wine or any type of alcoholic beverage produced in 2008, about 10 billion are closed by a natural cork stopper, and it is established that about 5% of these bottles have a defect taste of cork, which represents about 500 million bottles unfit for consumption, about 375 million liters!

Numerous other treatments have been described to reduce the taste defects of cork by coating the cork stoppers to avoid direct contact of the cork with the bottled liquid.

Thus, international demand WO2007 / 115612 discloses a plug formed from cork granules coated with a polyurethane resin.

Similarly, international demand WO97 / 30098 discloses a treatment of cork with a composition comprising a diisocyanate and a diol.

Similarly, international demand WO97 / 11894 discloses a process in which corks are immersed in a xylene bath and coated with a silicone rubber dispersion to form a deposit which is then fired.

Similarly, international demand WO2007 / 107209 discloses a cork stopper treatment in which the corks are coated with a hydrophilic polymeric layer, such as a cellulosic layer, based on starch or alcohol polykinetic, and a hydrophobic layer, such as a layer based on a silicone derivative.

Similarly, international demand WO96 / 28378 discloses a cork plug encapsulated in a layer, preferably PVC or polyurethane, formed for example by molding and heat treatment.

Similarly, international demand WO91 / 04836 discloses a cork stopper treatment comprising a washing step with a solution containing sodium hydroxide, sodium silicate and hydrogen peroxide, followed by a drying step, and a third step of treatment with a solution containing acetic acid, peracetic acid and hydrogen peroxide.

Similarly, international demand WO2004 / 076607 discloses a cork plug treatment comprising forming a polyolefin layer on the plug.

Similarly, international demand WO03 / 031276 discloses a cork stopper treatment comprising depositing a synthetic resin powder on the plug, and then melting this resin by infrared heating.

PROBLEMS POSED

• a) A ce jour, en ce qui concerne le problème du goût de bouchon, les systèmes connus de protection ou de traitement de bouchons en liège, se sont révélés soit peu efficaces pour atteindre leur objectif, soit difficiles ou coûteux à mettre en oeuvre dans les manufactures de bouchons.
  Quant aux systèmes connus de protection de la surface du bouchon en contact avec le liquide, ils conduisent à un résultat aléatoire en ce qui concerne la migration de molécules néfastes du bouchon vers le liquide conditionné, puisque dépendant du serrage du bouchon dans le col de la bouteille et des cheminements possibles de liquide entre le bouchon et le verre sur les surfaces non traitées.
  L'invention vise à obtenir des bouchons qui comprennent une barrière efficace à la migration des dites molécules néfastes.
  La demanderesse a également observé, dans un test effectué à partir de nombreux types de bouchons en liège du commerce, que ces bouchons, immergés chacun dans un verre d'eau organoleptiquement neutre, étaient susceptibles de donner à cette eau des odeurs et/ou des goûts de bouchons, après plus de 24 heures d'immersion totale. Ce test d'immersion dans l'eau permet de révéler, plus rapidement que dans du vin ou de l'alcool éthylique, une migration de molécules néfastes ou une altération de goût dues aux bouchons.
• b) Il est connu que les bouchons en liège naturel présentent une perméabilité à l'oxygène et à la vapeur d'eau variable d'un bouchon à l'autre. Cette grande variabilité de perméabilité, cette impossibilité de connaître à l'avance les caractéristiques physico-chimiques de chaque bouchon, est donc un handicap majeur pour obtenir une qualité constante. L'invention vise à produire des bouchons en liège naturel présentant une perméabilité à l'oxygène et à la vapeur d'eau située dans une plage restreinte et de valeur prédéterminée.
• c) Il est connu que les bouchons présentent des teneurs en humidité qui varient d'un bouchon à l'autre ainsi qu'au cours du temps, et cela, en fonction de nombreux paramètres, notamment avec l'humidité relative ambiante ou selon que le bouchon est ou non en contact permanent avec le liquide embouteillé. La teneur en humidité à l'intérieur du bouchon de liège est fondamentale pour le maintien de ses caractéristiques physiques durant toute sa vie, jusqu'à la première ouverture de la bouteille. Des variations de 3 à >10% d'humidité ont été mesurées sur différents lots de bouchons du commerce, avant introduction dans le col des bouteilles, alors que la norme prévoit de 4 à 8% d'humidité du liège. Ainsi les caractéristiques mécaniques de compression et de reprise élastique des bouchons dépendent en majeure partie de l'humidité contenue dans le bouchon. Plus un bouchon est chargé en humidité, plus il devient souple et plus ses caractéristiques mécaniques diminuent, ce qui entraîne aussi une perte d'étanchéité, au-delà d'un certain seuil d'humidité de l'ordre de 10%. L'invention vise donc à produire des bouchons en liège naturel présentant une humidité intérieure située dans une plage restreinte et de valeur prédéterminée.
• d) Dans un pourcentage non négligeable de cas, on observe, avec des bouchons en liège du commerce, des problèmes liés à l'ouverture de la bouteille et à l'extraction du bouchon, avec en particulier, lors du débouchage de la bouteille, une perte d'intégrité physique ou de tenue mécanique du bouchon, ce qui conduit à la fois à une extraction du bouchon difficile - il faut s'y prendre à plusieurs reprises pour extraire la totalité du bouchon du goulot -, et souvent à une contamination du liquide conditionné par des débris de ce bouchon, d'où une dégradation de la qualité et de la quantité buvable, du liquide embouteillé. L'invention vise à obtenir des bouchons en liège naturel qui conservent leur intégrité physique notamment lors de leur extraction du goulot, souvent de nombreuses années après le conditionnement du liquide.
• e) La demanderesse a également observé que les valeurs des forces d'enfoncement et d'extraction des bouchons en liège naturel pouvaient varier, pour un même lot homogène dans un rapport de 1 à 3, certaines valeurs dépassant largement les limites supérieures de la norme. Il s'agit là d'une hétérogénéité qui constitue un grave défaut.
  Lors de l'extraction de bouchons connus, on observe ainsi souvent de grandes variations de l'effort d'ouverture : si un effort trop faible peut être considéré comme un indice de mauvaise conservation, un effort trop important n'est pas non plus acceptable sur un plan pratique. Il convient de penser que les consommateurs ne sont dotés que d'une force physique « moyenne ». L'invention vise donc à obtenir des bouchons en liège naturel qui présentent un effort d'ouverture situé dans une plage restreinte et de valeur prédéterminée.
• f) Un autre inconvénient majeur, en particulier auprès des embouteilleurs, est celui des poussières de liège, libérées au cours des manutentions des bouchons, dans les différentes étapes des procédés de fabrications, jusqu'au moment de la pose du bouchon sur la bouteille. En effet, la demanderesse a observé que les bouchons standards du commerce généraient des poussières de liège dans les circuits de collecte, distribution et pose des bouchons sur les bouteilles. Il arrive aussi que ces poussières se retrouvent à l'intérieur des bouteilles, flottant sur le liquide embouteillé, en dépit de l'utilisation de systèmes d'aspiration placés sur les machines automatiques d'embouteillage.
• g) La demanderesse a également observé qu'une forte majorité des bouchons standards n'étaient pas nécessairement adaptés, en termes de niveau de barrière à l'oxygène ou à la vapeur d'eau, pour la conservation de vins, chaque vin nécessitant un certain niveau de barrière, ou une barrière située dans une plage de valeurs donnée. En effet, le vieillissement de certains vins implique un échange contrôlé d'oxygène, et donc un niveau de barrière prédéterminé. La perméabilité à l'oxygène des bouchons en liège naturel est très aléatoire et très variable d'un bouchon à un autre. Par exemple, sur un échantillonnage représentatif statistiquement d'un lot homogène de bouteilles fermées par des bouchons en liège naturel, il est apparu à plusieurs reprises que les valeurs de perméabilité des bouchons en liège naturel ou traités par colmatage pouvaient varier de 0.0001 à 0.1227 cm³/O₂/24heures par bouteille (AWRI - P.Godden & Al Enoforum 2005, 21-23 mars, Piacenza (Italie)), soit un rapport de 1 à 1000, entre les valeurs extrêmes. Il ne peut y avoir une maîtrise de la qualité du vin dans ces conditions.
  L'invention vise à obtenir des bouchons qui présentent une perméabilité à l'oxygène située dans une plage à la fois relativement étroite, comme déjà mentionné, et prédéterminée afin d'être adaptée au type de liquide ou de vin conditionné.
• h) Bien que le bouchage de bouteilles de vin soit un domaine en évolution permanente, il n'en demeure pas moins que la majorité des bouteilles de vin produites dans le monde étant fermées par un bouchon de liège naturel, le bouchon en liège naturel conserve, malgré ses inconvénients, une excellente image de marque liée à une idée de tradition. L'invention vise à obtenir des bouchons qui conservent l'aspect extérieur des bouchons traditionnels en liège naturel.
• i) De plus, ayant procédé à des essais de bouchage de bouteilles contenant des liquides sensibles à l'oxydation, contenant des boissons effervescentes et de bouteilles de boissons conditionnées sous pression, la demanderesse a constaté que les bouchons de l'art antérieur ne permettaient pas d'obtenir une étanchéité liquide et gazeuse en particulier avec des pressions à l'intérieur du récipient allant de 10 bar à 15 bar, soit de 1 MPa à 1,5 MPa, pour une plage de températures allant typiquement de 0°C à 50°C, et cela pendant une durée pouvant atteindre plusieurs années, voire plusieurs dizaines d'années. Les bouchons et traitements selon l'invention visent à résoudre ces problèmes.
• k) Enfin, s'agissant de produits de grande consommation tels que les bouchons en liège, la notion de coût de production - coût du traitement - est essentielle, tant en ce qui concerne les coûts d'investissement, la productivité et les coûts de production. Mais il faut aussi prendre en compte l'impact du procédé sur l'environnement, de même que la dangerosité du procédé, ce qui peut nécessiter des autorisations administratives, ou encore des investissements spécifiques liés à la sécurité et à la protection de l'environnement. L'invention vise un traitement simple, économique et de productivité élevée, et qui ne nécessite pas de moyens ou de mesures particulières.

These problems posed by natural cork stoppers, whether they are treated in a known manner or not treated, are numerous:

• a) To date, with regard to the problem of cork taste, the known systems for protecting or treating cork stoppers have proved to be either ineffective to achieve their objective, difficult or expensive to implement in the manufactures of caps.
  As for the known systems for protecting the surface of the stopper in contact with the liquid, they lead to a random result with regard to the migration of harmful molecules from the stopper to the conditioned liquid, since this depends on the tightness of the plug in the neck of the bottle and possible pathways of liquid between cap and glass on untreated surfaces.
  The aim of the invention is to obtain plugs that comprise an effective barrier against the migration of said harmful molecules.
  The Applicant has also observed, in a test made from many types of commercial cork stoppers, that these corks, each immersed in a glass of organoleptically neutral water, were likely to give this water odors and / or taste of corks, after more than 24 hours of total immersion. This immersion in water test reveals more quickly than in wine or ethyl alcohol, a migration of harmful molecules or an alteration of taste due to caps.
• b) It is known that natural cork stoppers have a permeability to oxygen and water vapor variable from one stopper to another. This great variability of permeability, this impossibility of knowing in advance the physicochemical characteristics of each stopper, is therefore a major handicap to obtain a constant quality. The aim of the invention is to produce natural cork stoppers having permeability to oxygen and water vapor within a restricted range and of a predetermined value.
• c) It is known that the plugs have moisture contents that vary from one plug to another as well as over time, and this, according to many parameters, especially with ambient relative humidity or depending on whether the plug is or not in permanent contact with the bottled liquid. The moisture content inside the cork is fundamental to maintaining its physical characteristics throughout its life, until the first opening of the bottle. Variations of 3 to> 10% moisture were measured on different lots of commercial corks, before introduction into the neck of the bottles, while the standard provides for 4 to 8% moisture cork. Thus, the mechanical characteristics of compression and elastic recovery of the plugs depend for the most part on the moisture contained in the plug. The more a plug is loaded with moisture, the more it becomes flexible and its mechanical characteristics decrease, which also results in a loss of tightness, beyond a certain moisture threshold of the order of 10%. The invention therefore aims to produce natural cork stoppers having an internal humidity within a restricted range and a predetermined value.
• d) In a significant percentage of cases, with commercial cork stoppers, problems are encountered with the opening of the bottle and with the extraction of the cork, in particular when the bottle is uncorked, a loss of physical integrity or mechanical strength of the plug, which leads to both a difficult plug extraction - it must be done repeatedly to extract the entire neck cap - and often to contamination liquid conditioned by debris of this plug, resulting in a degradation of the quality and the drinkable quantity of the bottled liquid. The object of the invention is to obtain natural cork stoppers which retain their physical integrity, in particular during their extraction from the neck, often many years after the liquid has been packaged.
• (e) The plaintiff has also observed that the values of the forces of driving and extraction of natural corks could vary for the same lot homogeneous in a ratio of 1 to 3, some values far exceeding the upper limits of the standard. This is a heterogeneity that is a serious defect.
  During the extraction of known plugs, we often observe large variations in the opening effort: if too little effort can be considered as an index of poor conservation, too much effort is not acceptable either. on a practical level. It should be thought that consumers have only "average" physical strength. The invention therefore aims at obtaining natural cork stoppers which have an opening force situated in a restricted range and of predetermined value.
• f) Another major disadvantage, especially with bottlers, is that of cork dust, released during the handling of corks, in the various stages of manufacturing processes, until the time of laying the cap on the bottle. Indeed, the Applicant has observed that standard commercial plugs generated cork dust in the circuits for collecting, dispensing and installing corks on the bottles. It also happens that these dusts are found inside the bottles, floating on the bottled liquid, despite the use of suction systems placed on automatic bottling machines.
• g) The Applicant also observed that a large majority of standard caps were not necessarily suitable, in terms of oxygen barrier level or water vapor, for the preservation of wines, each wine requiring certain barrier level, or a barrier within a given range of values. Indeed, the aging of certain wines implies a controlled exchange of oxygen, and therefore a predetermined level of barrier. The oxygen permeability of natural cork stoppers is very random and varies from one stopper to another. For example, on a statistically representative sample of a homogeneous batch of bottles closed by natural cork stoppers, it has repeatedly appeared that the permeability values of natural cork stoppers or treated by clogging could vary from 0.0001 to 0.1227 cm. ³ / a ₂ / 24hours per bottle (AWRI - P.Godden & Al Enoforum 2005, March 21-23, Piacenza (Italy)), a ratio of 1 to 1000, between the extremes. There can be no control over the quality of the wine under these conditions.
  The invention aims to obtain plugs which have an oxygen permeability in a relatively narrow range, as already mentioned, and predetermined to be adapted to the type of liquid or wine conditioning.
• h) Although corking wine bottles is a constantly evolving field, the fact remains that the majority of wine bottles produced in the world are closed by a natural cork, the natural cork keeps despite its disadvantages, an excellent brand image linked to an idea of tradition. The invention aims to obtain plugs that retain the appearance of traditional natural cork stoppers.
• i) In addition, having carried out bottle capping tests containing oxidation-sensitive liquids, containing effervescent drinks and bottles of pressurized beverages, the Applicant has found that the plugs of the prior art do not allow not to obtain a liquid and gaseous sealing, particularly with pressures inside the container ranging from 10 bar to 15 bar, ie from 1 MPa to 1.5 MPa, for a temperature range typically ranging from 0 ° C. to 50 ° C, and this for a period of up to several years, even several decades. The plugs and treatments according to the invention aim to solve these problems.
• (k) Finally, in the case of consumer products such as cork stoppers, the notion of cost of production - cost of treatment - is essential, both in terms of investment costs, productivity and costs of production. production. But it is also necessary to take into account the impact of the process on the environment, as well as the dangerousness of the process, which may require administrative authorizations, or specific investments related to safety and the protection of the environment. . The invention aims a simple treatment, economic and high productivity, and does not require special means or measures.

In general, starting from batches of so-called natural or so-called plugged plugs, the invention aims to transform any batch of corks into natural cork, with its heterogeneity and its variability of intrinsic properties, batch-to-batch variability, and the inside a same lot, in a batch of plugs with homogeneous characteristics, and low variability both from one batch to another and within the same batch.

More particularly, the invention aims to obtain plugs having properties - in particular oxygen permeability - adapted to the liquids to be packaged.

DESCRIPTION OF THE INVENTION

• a) on approvisionne un lot d'une pluralité de bouchons dits naturels (900a) et on imprègne ledit lot dans une composition liquide CP (903) comprenant au moins une matière polymérique P, sous une pression P₁ supérieure à la pression atmosphérique P_A, de manière à obtenir un lot dit imprégné,
• c) puis, ledit lot imprégné est essoré, de manière à obtenir un lot dit essoré,
• d) enfin, ledit lot essoré est soumis à un traitement thermique,

de manière à obtenir un lot de bouchons dit traités (928), chaque bouchon (928) présentant une « peau composite » (204, 301, 304) de liège L imprégné de matière polymérique P, représentée symboliquement par « L+P ».According to the invention, the treatment of natural cork stoppers successively comprises the following steps a, c and d:

• a) supplying a batch of a plurality of so-called natural plugs (900a) and impregnating said batch in a liquid composition CP (903) comprising at least one polymeric material P, at a pressure P ₁ greater than the atmospheric pressure P _A , so as to obtain a so-called impregnated batch,
• c) then, said impregnated batch is wrung out, so as to obtain a so-called wrung batch,
• d) finally, said drained batch is subjected to a heat treatment,

so as to obtain a batch of so-called treated plugs (928), each plug (928) having a "composite skin" (204, 301, 304) of cork L impregnated with polymeric material P, represented symbolically by "L + P".

1. a) on approvisionne un lot d'une pluralité de bouchons dits naturels et on imprègne ledit lot dans une composition liquide CP comprenant au moins une matière polymérique P, sous une pression P₁ supérieure à la pression atmosphérique P_A, de manière à obtenir un lot dit imprégné,
2. b) puis, ledit lot imprégné est traité sous vide sous une pression P₂ < P_A, de manière à obtenir un lot traité sous vide,
3. c) puis, ledit lot traité sous vide est essoré, de manière à obtenir un lot dit essoré,
4. d) enfin, ledit lot essoré est soumis à un traitement thermique,

de manière à obtenir un lot de bouchons dit traités, chaque bouchon présentant une « peau composite » de liège L imprégné de matière polymérique P, représentée symboliquement par « L+P ».According to the invention, a complementary step b) of vacuum treatment can be incorporated, the treatment of natural cork stoppers then comprising successively the following steps a) to d):

1. a) supplying a batch of a plurality of so-called natural plugs and impregnating said batch in a liquid composition CP comprising at least one polymeric material P, at a pressure P ₁ greater than the atmospheric pressure P _A , so as to obtain a batch said impregnated,
2. b) then, said impregnated batch is treated under vacuum under a pressure P ₂ <P _A , so as to obtain a batch treated under vacuum,
3. c) then, said batch treated under vacuum is drained, so as to obtain a lot said wrung,
4. d) finally, said drained batch is subjected to a heat treatment,

so as to obtain a batch of so-called treated plugs, each plug having a "composite skin" of cork L impregnated with polymeric material P, represented symbolically by "L + P".

The plugs of this batch have on their entire accessible surface, outer surface and inner surface of the cavities or anfractuosities of said plugs, a surface area of cork L, comprising a penetration of said polymeric material P in its mass with an incorporation of said polymeric material P cork, so that said treated plug has the composite skin "L + P".

Thanks to this treatment according to the invention, the Applicant has succeeded in impregnating a layer of surface cork or skin with said liquid composition CP.

• la surface dite externe du bouchon comprenant la surface cylindrique du bouchon ainsi que les deux faces circulaires aux extrémités du bouchon,
• la surface dite interne comprenant toutes les surfaces des cavités, des fissures et de tout type d'anfractuosités ouvertes, c'est-à-dire débouchant sur ladite surface externe.

This skin corresponds to all the accessible surfaces of the stopper and which comprise corky tissue, these accessible surfaces being:

• the so-called outer surface of the stopper comprising the cylindrical surface of the stopper and the two circular faces at the ends of the stopper,
• the so-called internal surface comprising all the surfaces of the cavities, cracks and any type of open crevices, that is to say opening onto said external surface.

Thus, the Applicant has found that cork, or at least its main constituent, the alveolar soft tissue, was able to absorb said CP liquid composition, as has been demonstrated in particular using micrographs with contrast agents.

However, as a natural cork is a heterogeneous material which includes, in addition to cellular honeycomb tissue that provides elasticity to the plug, portions, typically formed of other lignin and tannin-rich constituents, which may be more hard and more impermeable, including said liquid composition under pressure, a plug may therefore present locally, particularly at the level of the heterogeneities of the cork or in the anfractuosities of the plug, surface portions having a skin "L + P" of low thickness, or possibly covered with a layer of polymeric material "P".

As will become apparent in the following description and in the examples, the succession of at least steps a), c) and d) of the treatment is necessary to obtain plugs that solve all the problems posed, at least when the batch of corks stocked is a lot of so-called natural corks. In particular, it should be noted that with the naked eye, the corks obtained by the treatment according to the invention retain the general appearance of the natural cork stoppers, which would not be the case if the cork was covered with a polymeric or film-forming composition. The treatment according to the invention therefore gives the stopper a composite skin "L + P" based on cork L and polymeric material P, largely intended to be placed in contact with the neck of the container and partly in contact with the conditioned liquid. this skin forming a deformable plastic material which continues, after plugging, to marry, under the effect of the radial compression, then the elastic recovery of the cork, the relief of the inner surface of said neck.

• de réduire considérablement la migration de molécules néfastes du bouchon vers le liquide conditionné, de manière à éliminer le « gout de bouchon », les bouchons selon l'invention mis au contact d'un milieu hydroalcoolique, n'en altèrent pas le goût ou l'odeur.
• d'obtenir des bouchons présentant une perméabilité à l'oxygène et à la vapeur d'eau située dans une plage restreinte et de valeur prédéterminée.
• d'obtenir des bouchons présentant une teneur en humidité à l'intérieur des bouchons sensiblement constante d'un bouchon à l'autre et maintenue à l'intérieur de la plage de 4 à 8% d'humidité du liège prévue par la norme, de manière à ce que tous les bouchons présentent les mêmes caractéristiques mécaniques de compression et de reprise élastique, et une faible perte de ces caractéristiques mécaniques au cours du temps.
• d'obtenir des bouchons qui conservent leur intégrité physique notamment lors de leur extraction du goulot, souvent de nombreuses années après le conditionnement du liquide.
• d'obtenir des bouchons qui présentent un effort d'ouverture situé dans une plage restreinte et de valeur prédéterminée.
• d'obtenir des bouchons en liège naturel exempts de poussières de liège.
• d'obtenir des bouchons de perméabilité adaptée à leur usage particulier adaptés au type de liquide ou de vin conditionné.
• d'obtenir des bouchons qui conservent visuellement l'aspect de bouchons en liège naturel, que ce soit lors du bouchage que lors du débouchage des bouteilles, de manière à véhiculer une image de « tradition ».
• d'obtenir des bouchons présentant une étanchéité liquide et gazeuse, et cela même dans le cas de contenus liquides sous pression.
• d'obtenir ces bouchons avec un procédé particulièrement économique tant en coûts d'investissement, faisant appel à des équipements courants, que de coûts de fonctionnement, procédé de grande productivité et qui, par ailleurs, ne présente ni risques pour l'environnement, ni risques sanitaires ni une dangerosité quelconque dans sa mise en oeuvre.

As will be seen in more detail in the following, the invention, by virtue of this succession of at least steps a), c) and d), makes it possible to solve the problems posed. Indeed, such a treatment of natural cork stoppers allows:

• to considerably reduce the migration of harmful molecules from the stopper to the conditioned liquid, so as to eliminate the "taste of the stopper", the stoppers according to the invention placed in contact with a hydroalcoholic medium, do not alter the taste or the 'odour.
• obtaining plugs having permeability to oxygen and water vapor within a restricted range and of predetermined value.
• to obtain plugs having a moisture content inside the plugs substantially constant from one plug to the other and maintained within the range of 4 to 8% cork moisture provided by the standard, so that all plugs have the same mechanical characteristics of compression and elastic recovery, and a small loss of these mechanical characteristics over time.
• to obtain plugs that retain their physical integrity especially during their extraction of the neck, often many years after the liquid conditioning.
• to obtain plugs that have an opening force within a restricted range and a predetermined value.
• to obtain natural cork stoppers without cork dust.
• obtain patches of permeability adapted to their particular use adapted to the type of liquid or wine conditioning.
• to obtain corks that visually retain the appearance of natural cork stoppers, both during corking and when uncorking bottles, in order to convey a "tradition" image.
• to obtain plugs having a liquid and gaseous sealing, and this even in the case of liquid contents under pressure.
• to obtain these plugs with a particularly economical process in terms of investment costs, using standard equipment, as well as operating costs, which is a process of high productivity and which, moreover, presents neither risks to the environment nor health risks or any dangerousness in its implementation.

DESCRIPTION OF THE FIGURES

The figure 1a is a view of a bottle neck (101) closed by a plug (100) and covered with an overcap (102), this view forming, on the half-right portion of the figure, a half-view of side, and on the half-left part of the figure, an axial half-section in the axial direction (104) of the cap and the neck.

The Figures 1b and 1c are cross-sectional portions of the plug, perpendicular to its axial direction, which illustrate said composite skin (204) forming an outer composite skin (301). The figure 1b is a photograph - macrography - of this sectional portion, a black dye tracer having been incorporated into the liquid composition. The figure 1c is the schematic representation of the figure 1 b.

The Figures 2a to 2d are cups of plugs (100) obtained according to the invention. In order to be able to observe the impregnation of the plug in its anfractuosities or cracks, by visual or microscopic observation, a black tracer dye has been added to the liquid composition CP. It is thus very clearly perceived that the crevices such as lenticels, holes, cracks, crevices are impregnated with the liquid composition colored black so as to obtain a visual contrast.

The figure 2a is a photograph showing a left half-cut (300b) of a cork.

The figure 2b is a diagrammatic representation of a straight half-cut (300a) of the plug of the figure 2a .

The Figure 2c is an enlarged photograph of the framed portion A of the figure 2a .

The figure 2d is a schematic representation of the Figure 2c .

The figure 3 is a diagram relating to plugging and plugging forces, the extraction having been carried out 26 days after capping and storage at room temperature at 15 ° C.

On the abscissa are the tests E0 to E7 and the ordinate the forces in daN, the measurements being made on a sampling of 10 caps.

• Courbe A : valeur maximale en extraction
• Courbe B : valeur moyenne en extraction
• Courbe C : valeur minimale en extraction
• Courbe D : valeur maximale en bouchage
• Courbe E : valeur moyenne en bouchage
• Courbe F : valeur minimale en bouchage.

The E0 test corresponds to standard commercial corks made of natural cork which are not clogged and treated with silicones. Tests E1 to E7 correspond to plugs obtained with the treatment according to the invention.

• Curve A: maximum extraction value
• Curve B: average extraction value
• Curve C: minimum extraction value
• Curve D: maximum capping value
• Curve E: mean value in capping
• Curve F: minimum capping value.

The figure 4 is a diagram with the moisture content of the cork after 9 months of stay in the neck of an empty bottle and stored at 15 ° C.

• Courbe A : valeur maximale
• Courbe B : valeur moyenne
• Courbe C : valeur minimale

On the abscissa are the tests E0 to E7 and the ordinate humidity in%, the measurements having been carried out on a sampling of 10 stoppers.

• Curve A: maximum value
• Curve B: average value
• Curve C: minimum value

The figure 5 shows schematically, in axial section, the device used to measure the oxygen permeability of a bottle portion (600) provided with the plug (100) to be tested. This bottle portion (600) is secured to a metal platen (611) by a bead (612), the platen being provided with gas supply tubes (613) and gas outlet tubes (614), a sealed envelope (610) covering said bottle portion (600).

The figure 6 schematically represents a first device mode for the implementation of steps a) to d) of the object of the invention.

The Figures 7a to 9c illustrate another device modality for the implementation of steps a) to d) of the object of the invention. In this modality, all the steps of the treatment are carried out, without transfer of the plugs, in a wiper reactor (800).

The Figures 7a to 8b are cross sections according to the CC plane of the Figure 9c .

The figure 7a illustrates step a) pressure impregnation.

The figure 7b illustrates step b) vacuum desorption processing.

The figure 8a illustrates step c) of spinning.

The figure 8b illustrates step d) of drying.

The Figures 9a to 9c are longitudinal sections along the axis or central shaft (803, 803 ') and according to the plane AA of the figure 7a , which illustrate different variants of wiper reactors (800).

The figure 9a represents a wiper reactor (800, 800a) of spherical shape.

The figure 9b represents a wiper reactor (800, 800b) of cylindrical form.

The Figure 9c represents a wiper reactor (800, 800c) of bi-frustoconical shape.

DETAILED DESCRIPTION OF THE INVENTION

In the treatment according to the invention, in step a) of said treatment, said batch of plugs (900a) can be immersed in a first pressure-resistant container (902) containing said liquid composition (903), and said container (902) under pressure with an air pressure P ₁ of between 2 and 6 bars and preferably of 3 to 5 bars, said air pressure P ₁ being applied inside said first container (902) on a duration between 1 and 15 minutes and preferably from 3 to 10 minutes.

With regard to step a) impregnation, and after having tested several coating application methods, such as brush removal, spray spraying, dipping, soaking under ultrasound, it appeared to the plaintiff that these methods did not solve the problems posed. These problems were only solved when the treatment included a pressure impregnation of the polymeric CP liquid composition allowing this liquid composition CP to penetrate homogeneously inside the structure of the cork, in the cracks, the craters, slots, and galleries created by insects, or other open crevices opening on the surface of the plug. But, as we can see on the Figures 2a and 2b it seems that during step a) of impregnation under pressure, almost all the anfractuosities is impregnated with said liquid composition CP, even in the case of crevices or cracks not directly open. It therefore seems that the pressure used in step a) of the treatment makes it possible to introduce said liquid composition CP into the entire network of crevices or crevices of the plug.

The Applicant has thus observed that at ambient temperature, using the film-forming or polymeric coating with a colored tracer, and for example applying a pressure of 5 bar for 3 minutes or 3 bar for 5 minutes, the penetration goal was totally achieved.

The same tests were carried out under different pressures at temperatures ranging between 20 ° C and 38 ° C, without observing significant variations in the results. However, the viscosity of the polymer coating decreasing as a function of the rise in temperature, it was found that the duration of the impregnation under pressure could be decreased in the ratio of the lowering of the viscosity ratio. Thus, preferably, and also to overcome external temperature variations, it will be preferable to operate to perform the impregnation under pressure at a relatively constant temperature of 38 ° C ± 2 ° C.

Moreover, the Applicant has also observed in his experiments, that a sudden setting off pressure, favored the desorption of surplus CP liquid composition.

So, and as one can see on the figure 6 a batch of raw corks (900) previously conditioned in a suitable net (901), whose mesh size does not exceed the smallest dimension of the plugs to be treated, is introduced into a reactor or reservoir (902) resistant to pressure, inside which will have previously introduced the liquid composition CP (903) typically comprising an emulsion of acrylic polymers in aqueous aqueous phase or an aqueous composition based on EVOH, copolymer of ethylene and vinyl alcohol.

The batch of caps must be completely immersed in the liquid composition (903), then the lid (904) of said tank will be hermetically sealed. An overpressure of filtered and controlled air (905) is then applied inside the tank (902). The reservoir (902) is temperature controlled to maintain the viscosity of the liquid composition (903) constant. The pressure is then suddenly relaxed inside the tank (902) and the lid (904) is removed. The net (901) is raised above the level of the liquid composition (903) and allowed to drain for a few moments.

At the end of this first impregnation step, and before proceeding to the next step, it has been observed that a step of draining the plugs made it possible to save a significant amount of the liquid composition (903). . Thus a dewatering time of the order of one to two minutes, accompanied by shaking saves about 5 to 20% of the amount of liquid composition (903). Thus, any loss of liquid composition is otherwise avoided at least very limited.

The applicant has observed that the amount of CP liquid composition consumed could vary according to various parameters, such as the surface tension of the plugs, the viscosity of the liquid composition CP and therefore its temperature, but also the quality of the plugs. Thus it has been observed that "0" quality corks (superior quality called "Super") without slots or craters or galleries, consumed much less polymeric material, than lower quality corks, for example, quality 3 or beyond, these being dotted with holes, craters, slots and galleries for storing a greater amount of liquid composition CP (903) and polymeric material P. As will be indicated later, the treatment according to the invention can also be used with so-called plugged plugs, typically formed from plugs of grade 3 or beyond. In this case, the anfractuosities and cracks of the plug being already clogged, the consumption of liquid composition will be even more reduced.

In the optional step b) of the treatment, said impregnated batch can be treated under vacuum, inside a vacuum-resistant container (902 '), with a pressure P ₂ ranging from 0.1 to 4 mbar. and preferably from 0.5 to 1.5 millibar.

Said vacuum may be made inside said container for at least one minute, and preferably in cycles, with the atmospheric pressure being restored between each cycle, the number of cycles ranging from 1 to 10, and preferably ranging from 3 to 7, each cycle comprising a vacuum phase for about one minute.

In the case of a batch of so-called natural corks, the Applicant has found that this vacuum desorption step was necessary. Indeed, in the absence of desorption under vacuum, the Applicant has observed the formation of bubbles or micro-bubbles on the surface of the plug at the time of step d) of drying and cooking of the polymeric material P, which night much at the same time to the technical quality of the cap, and its appearance and aesthetics. The Applicant has assumed that the vacuum treatment makes it possible to expel small crevices or cracks an excess of CP liquid composition that the spinning, in step c) of the treatment, would not eliminate.

The desorption operation of step b) is produced by the depression of the reservoir containing the batch of plugs to be desorbed. Typically, the tests have shown that a pressure P ₂ of 4 mbar can be used per cycle of one minute.

The Applicant has observed that several alternating cycles of evacuation and relaxation, significantly increased the desorption level. Thus, series of 3 to 5 alternating cycles of evacuation for 1 min and relaxations gave excellent results. The conditions of this desorption are such that this desorption affects only the liquid composition CP "free" which is in the crevices, and not the liquid composition that has penetrated into the cork to form said composite skin "L + P".

In step c) of the treatment, after venting, the batch of vacuum treated plugs can be, once introduced inside a wringer (910), wrung out in cycles, each cycle comprising a spinning phase lasting from 0.5 to 5 minutes, preferably between 1 and 3 minutes, with a number of cycles of between 1 and 5 and preferably between 2 and 3, a phase of stirring plugs being interposed between each phase spin, lasting between 3 seconds and 1 minute and preferably between 5 seconds and 30 seconds, and during which the plugs change position and place inside the drum of the wringer (910).

Typically, the batch of plugs can be subjected to a centrifugal force of between 20 and 80 Newtons, preferably between 30 and 60 Newtons.

The Applicant has observed that this dewatering step c), before the firing of the coating, was necessary to complete or supplement the desorption step b), in order to avoid the excess of polymeric emulsion in the anfractuosities of the plugs, causing lingering bubbles after cooking. In addition to the unsightly appearance of these bubbles, they are torn during handling, distribution and installation of plugs thus releasing into the air cork particles may redeposit on different equipment and possibly in the bottled liquid.

Likewise, the spin eliminates the presence of agglomerates of liquid composition CP on the surface of the stopper. All the plugs of a batch having undergone the stages of pressurization and then of evacuation, followed by spinning, respecting the cycles tested by the Applicant, have an absolutely clean outer surface and an example of any visible surface defect. with the naked eye, of any mass of liquid composition CP or polymeric material P.

The spin can be practiced in a drum machine with vertical or horizontal axis. Horizontal axis machines will be preferred because of the possible brewing steps between two spin sessions. These stirrings allow the plugs to move to provide different angles of extraction of coating product and thus to homogenize this operation.

The Applicant has shown that the choice of a drum machine with a diameter of 450 to 500 mm for a range of rotation speeds of 1200 to 1500 revolutions per minute made it possible to solve the problem posed, provided that cycles were observed. brewing at low speed: about 60 rpm. Preferably, alternating stirring with inversion of the direction of rotation, and spin.

When a net is used to contain a batch of stoppers, the Applicant has shown that the stoppers could be introduced into the drum of the wringer, pre-packed in the net already used during the soaking-impregnation and desorption, said net, typically meshes of the order of 10x10mm having a global volume slightly greater than that of the drum of the wringer, so as not to thwart the effects of centrifugal force during the spin cycles.

In step d) of the treatment, after having extracted the batch of plugs (921) from the wringer (910) in step c) of the treatment, said batch of plugs (921) can be treated in a chamber ( 920), by a flow of hot air at a rate between 3.0 and 20.0 meters per second and preferably between 5.0 and 10.0 meters per second, so as to form said heat treatment, said treatment thermal being intended in particular to remove a solvent from said liquid composition CP, when said liquid composition CP comprises a solvent.

At the end of step d) of the treatment, the batch of cap can be cooled by a flow of cold air, and possibly the speed of said cold air flow can be increased beyond 15 m / s, so as to expel said batch of caps from said enclosure, and thus to collect the batch of plugs directly into a bag or container adapted for this purpose.

Said flow of hot air may be applied at a temperature between 80 and 120 ° C and preferably between 90 and 100 ° C for a period of between 3 and 15 minutes and preferably between 5 and 10 minutes.

However, as a first step, said flow of hot air may be applied at a temperature of between 40 and 80 ° C. and preferably between 50 and 70 ° C. for a duration of between 1 and 10 minutes and preferably between 2 and 5 minutes.

Preferably, after having applied said flow of hot air, the heating of said flow of hot air can be stopped, said flow of air then passing at ambient temperature, so as to cool at ambient temperature said batch of plug, while a time substantially equivalent to that of said heat treatment.

After having tested various processes, such as the traditional oven ventilated, the microwaves, it appeared to the applicant that during the operation of evaporation of the solvent phase and the polymerization of the coating, the stoppers should not, preferably , stay in static contact with a wall, so as to obtain plugs having an excellent appearance of traditional stopper and avoid the presence of visible marks on the plugs.

The applicant has developed a drying-cooking system as illustrated on the figure 6 . After various tests and a development phase, the solution of the levitation of plugs under forced hot air flow was found to be excellent for obtaining plugs without surface defects.

1. 1 - 40 à 60°C durant 2 à 3 minutes
2. 2 - 70 à 120°C durant 3 à 15 minutes, et de préférence de 80 à 90°C durant 5 minutes, puis refroidissement à température ambiante sur une durée équivalente.

A l'issue de l'étape d) du traitement, le lot de bouchon peut être refroidi par un flux d'air froid la vitesse, et, éventuellement, la vitesse dudit flux d'air froid peut être ensuite augmentée au-delà de 15 m/s, de manière à expulser ledit lot de bouchons hors de ladite enceinte, et ainsi de manière à recueillir le lot de bouchons directement dans un sac ou récipient adapté à cet effet.The polymeric emulsion in aqueous phase forming said liquid composition requires a phase of evaporation of the solvent. When the solvent in question is water, which is the preferred case, the water must be evaporated, before coagulation and polymerization of the coating, otherwise bubble formation would be observed. The following Time / Temperature cycle will be preferred:

1. 1 - 40 to 60 ° C for 2 to 3 minutes
2. 2 - 70 to 120 ° C for 3 to 15 minutes, and preferably 80 to 90 ° C for 5 minutes, then cooling to room temperature for an equivalent period.

At the end of step d) of the treatment, the batch of cap can be cooled by a flow of cold air speed, and possibly the speed of said cold air flow can then be increased beyond 15 m / s, so as to expel said batch of plugs out of said enclosure, and so to collect the batch of plugs directly into a bag or container adapted for this purpose.

According to another modality of the treatment according to the invention, in step a) of the treatment, it is possible to supply a batch of so-called plugged plugs, and the step b) of evacuation can be eliminated. Indeed, the invention applies to all types of plugs. For obvious economic reasons, it will be preferable to use it with types of caps of relatively economic cost, which is the case of so-called natural plugs. But so-called plugged plugs are also of a substantially similar cost insofar as the additional cost due to clogging treatment is substantially balanced by the lower cost of the starting cork, the latter, of lower quality, having more crevices or cracks, whether in number or depth.

Since the cracks have been clogged beforehand, the desorption step b) plugs can thus be suppressed, having no reason to be.

Advantageously, the fluids used at the different stages of said treatment, whether in particular the compressed air in step a) of the treatment, or of the hot air in step d) of the treatment, must be neutral. and free of germs, bacteria, yeasts and all contaminating sources of pollution for the liquids closed by the corks thus treated.

In the treatment according to the invention, said liquid composition CP (903) may comprise, in addition to said polymeric material P, at least one additive A intended to promote the sliding of the stopper in contact with the glass, so that said treated stopper a "skin" of composition symbolically represented by "L + P + A".

1. a) agrées pour le contact alimentaire,
2. b) aptes à former une barrière aux dites molécules néfastes,

ladite matière polymérique P étant de préférence une émulsion de polymères acryliques en milieu aqueux ou une composition aqueuse à base d'EVOH, un copolymère d'éthylène et d'alcool vinylique.In the treatment according to the invention, said liquid composition CP (903) can form an emulsion or a dispersion in aqueous phase of at least one polymeric material P chosen from polymeric materials:

1. a) approved for food contact,
2. b) capable of forming a barrier to said harmful molecules,

said polymeric material P preferably being an acrylic polymer emulsion in an aqueous medium or an aqueous EVOH-based composition, a copolymer of ethylene and vinyl alcohol.

1. a) une dite première succession d'au moins les étapes a), c) et d), à partir d'une dite première composition liquide polymérique CP₁, formée typiquement par ladite composition liquide CP comprenant ladite matière polymérique P, de manière à former une dite première imprégnation,
2. b) et un traitement complémentaire comprenant, par exemple, une dite seconde succession d'au moins les étapes a), c) et d), à partir d'une dite seconde composition liquide polymérique CP₂, au moins ladite seconde composition liquide polymérique CP₂ comprenant ledit additif A destiné à favoriser le glissement desdits bouchons, de manière à former une dite seconde imprégnation, de manière à que ledit bouchon traité présente une « peau » composite de composition représentée symboliquement par « L+P / A ».

According to another embodiment of the invention, said treatment may comprise:

1. a) a said first succession of at least steps a), c) and d), from a said first polymeric liquid composition CP ₁ , typically formed by the said liquid composition CP comprising the said polymeric material P, so as to forming a said first impregnation,
2. b) and a complementary treatment comprising, for example, a said second succession of at least steps a), c) and d), from a said second polymeric liquid composition CP ₂ , at least the said second liquid polymer composition CP ₂ comprising said additive A intended to promote the sliding of said plugs, so as to form a said second impregnation, so that said treated plug has a composite "skin" of composition symbolically represented by "L + P / A".

Said first and second polymeric compositions may be different, and for example, only the second impregnation may comprise said additive A.

It has not yet been possible to establish precisely whether the second impregnation is superimposed and / or whether it is mixed with the first impregnation.

Said liquid composition CP (903), CP ₁ or CP ₂ may comprise an elastomeric material E chosen from: butyl rubber, nitrile rubber, thermoplastic elastomers such as SIS (styrene isoprene styrene), SBS (styrene butadiene styrene), SEBS (styrene ethylene butylene styrene), MS Polymer (Modified Silicon Polymer) or PDMS (Polydimethylsiloxane).

Said additive A intended to promote the sliding of the plug in contact with the glass may be an anionic emulsion wax, typically based on paraffin wax or carnauba wax or a silicone resin when said first liquid polymer composition CP ₁ comprises said composition based on EVOH, in order to cover said EVOH-based polymeric material P with a layer forming both a water barrier and a slip agent, said additive A being able to be an additive A ₂ constituting said second liquid polymer composition CP ₂ said second polymeric liquid composition then being free of EVOH.

Said liquid composition CP (903) may comprise a micronized mineral filler B forming a barrier, in particular to the diffusion of gases, said inorganic filler being chosen from: silica SiO ₂ , a silicon oxide SiO _x (with x <2), titanium oxide TiO ₂ , micronized clay, kaolin, barium sulfate.

In step a) of the treatment according to the invention, said liquid composition CP (903) can have a dynamic viscosity at 20 ° C of between 5 and 1000 cps (centipoise), and preferably between 10 and 800 cps, of in such a way that said CP liquid composition (903) can penetrate the crevices of the natural cork stoppers and form said skin or said composite skin. In an advantageous embodiment, said dynamic viscosity is between 5 and 100 cps, and preferably between 10 and 40 cps.

Advantageously, at least during steps a) and b) of the treatment according to the invention, and according to the technical modalities of implementation of the treatment according to the invention, and in the case of the process as illustrated on the figure 6 said batch of plugs may be contained in a mesh of chemical nature and of mesh size (for example 10 mm × 10 mm) adapted, capable of passing said liquid composition CP (903) while remaining inert with respect to said liquid composition, and with a mesh size smaller than the smallest dimension of the corks to be treated, so as to have to manipulate a net in which is located said batch of corks, during steps a) to c) of treatment.

Another object of the invention is constituted by a cork, typically a batch of corks, obtained by the treatment according to the invention, and characterized in that it has on its entire accessible surface, outer surface and surface internal cavity or crevice said plugs, a cork surface area L, comprising a penetration of said polymeric material P in its mass with an incorporation of said polymer material P cork, so that said treated plug has a composite skin (204); , 301, 304) of composition symbolically represented by "L + P", said composite skin (204, 301, 304) having a thickness E of at least 10 μm and up to 1 mm, depending on the local hardness or porosity of the natural cork or its constituents.

Typically, said polymeric material P may be an acrylic resin with a density of between 0.95 and 1.2, and preferably between 0.98 and 1.00, or an aqueous composition based on EVOH, an ethylene copolymer and polyvinyl alcohol.

As already indicated, the presence of a "L + P" composite skin is not exclusive of the possibility of having at least locally a part of said polymeric material P deposited on the surface of the cork, in particular within the crevices. of the cap.

According to the invention, said surface area of cork L forming said composite skin (204, 301, 304) can comprise, in addition to the incorporation of said polymeric material P cork, the incorporation of said additive A intended to promote the sliding of the cork in contact with the glass, so that said treated plug has a composite skin of composition symbolically represented by "L + P + A" or "L + P / A" according to whether said additive A is incorporated in said polymeric material P or covers said polymeric material P.

Said surface area of cork L may comprise, in addition to the incorporation of said polymeric material P to the cork and the incorporation of said additive A, the incorporation of at least one adjuvant chosen from: a micronized mineral filler B forming a barrier, in particular to the diffusion of gases, an elastomeric resin E.

Another object of the invention is the use of corks according to the invention, or obtained by the treatment according to the invention, for sealing containers, typically made of glass, containing alcohols, wines or spirits.

DESCRIPTION OF EXAMPLES A) Starting materials selected for testing:

A1) Cork corks : A supply of untreated corks has been supplied to natural cork processors: these plugs, known as natural corks, have not undergone any treatment other than washing with hot water, are called natural. These natural cork stoppers are of standard dimensions 45mmx24mm (height x diameter).

In addition, we have also supplied lots of corks plugged.

• On a sélectionné et approvisionné, comme composition liquide comprenant ladite matière polymérique P choisie parmi les matières agrées pour le contact alimentaire :
  • A20 = Michem Coat™ MC40EAF-E de Michelman Inc.
  • A21 = VaporCoat™ 2200^E de Michelman Inc.

A2) Liquid compositions comprising a film-forming or polymeric material

• A liquid composition comprising said polymeric material P selected among the materials approved for food contact has been selected and supplied:
  • A20 = Michem Coat ™ MC40EAF-E from Michelman Inc.
  • A21 = VaporCoat ™ 2200 ^E from Michelman Inc.

These are dispersions of acrylic resins in aqueous emulsion.

These two materials were selected after testing with a large number of materials suitable for food contact.

However, comparative test batteries have demonstrated a better match of the Vaporcoat ™ 2200 ^E to the problem. The physico-chemical characteristics of the MC40EAF-E do not allow it to be applied at room temperature in a simple process. It is necessary to apply high pressures, greater than or equal to 5 bar at least 38 ° C and longer durations, greater than 5 minutes, to obtain correct results.

The Applicant has therefore selected Vaporcoat ™ 2200 ^E as polymeric liquid composition CP to prepare and test the plugs according to the invention.

In addition, a liquid composition comprising said polymeric material P selected among the materials approved for food contact, a Kuraray EVOH composition, reference AQ-4104, was selected and supplied under reference A22.

A3) Additives A intended to promote the sliding of the cap in contact with the glass:

• A30 = ML160PFHS.E by Michelman Inc. (Carnauba Wax Emulsion)
• A31 = ML723HSA-E from Michelman Inc. (Paraffin emulsion).

Selection of these additives: Slip tests on glass, as well as full-length tests on plugs, with statistically representative series, made it possible to demonstrate that Vaporcoat 2200 ^E posed a problem of adherence to glass , to the point that the driving and extraction efforts found some values very outside the higher ranges of the standards in force. Many additives have been tested and two of them (A30 and A31) have been selected to carry out comparative tests compared to the reference products, which are the natural cork stoppers.

A4) Mineral fillers B intended to form a barrier to gases:

The following commercial products have been supplied: silica SiO ₂ , talc, ...

A5) Other raw materials:

Silicone and synthetic rubber-based elastomer dispersions, particularly a Bluestar silicone dispersion, CAF 72582, have been supplied under reference A50.

B) Equipment for implementing the treatment according to the invention

The various tests carried out implemented the treatment of the invention as schematically represented on the figure 6 .

• B1- Un premier récipient (902) apte à tenir à une pression de 5 bar, d'une capacité de 20 l, muni d'un couvercle amovible (904) doté d'un manomètre (905) et d'une arrivée d'air comprimé.
• B2- Un second récipient (902'), sensiblement de même capacité que le premier récipient (902), apte à tenir un vide, à savoir à une pression résiduelle 0,1 millibar, ledit second récipient (902') étant muni d'un couvercle amovible (904') doté d'un vacuomètre (905') et d'une prise de vide connectée à une pompe à vide.
• B3- Une essoreuse (910) dotée d'un tambour à vitesse variable, et d'une pompe pour extraire la composition liquide filmogène récupérée.
• B4- Un dispositif de séchage comprenant :
  • une colonne verticale de séchage formant un tube cylindrique (920), apte à être alimentée en air (chaud ou froid) par sa partie inférieure, et comprenant :
    • * à sa partie inférieure, une grille inférieure ajourée (924) formant support pour le lot des bouchons à sécher,
    • * à son extrémité supérieure, une grille supérieure ajourée amovible (925) de manière à laisser passer l'air chaud ou froid, mais à retenir les bouchons dans l'enceinte verticale cylindrique (920),
    • * à sa partie supérieure - juste au-dessous de ladite extrémité supérieure - un conduit tubulaire latéral supérieur (927) débouchant dans ladite enceinte verticale par une ouverture, apte à être tenue fermée ou ouverte grâce à un volet mobile (926), permettant le transfert des bouchons jusqu'à un moyen de conditionnement, tel un filet (929) .
  • une turbine (922) de propulsion d'air dans un conduit latéral inférieur,
  • un moyen de chauffage de l'air, tel que des résistances électriques chauffantes (923).
• B5- Des moyens de pilotage centralisés de ces équipements, avec enregistrement des paramètres. Ces moyens n'ont pas été représentés sur la figure 6.
• B6 - Un filet de rétention des bouchons apte à contenir 100 bouchons par essai. Tous les équipements ont été approvisionnés dans le commerce, à l'exception du dispositif de séchage de B4 qui a été conçu et réalisé dans le cadre de l'invention.

For this, we supply or manufacture the various necessary equipment E, namely:

• B1- A first container (902) adapted to hold at a pressure of 5 bar, with a capacity of 20 l, provided with a removable cover (904) equipped with a pressure gauge (905) and an inlet of pressurized air.
• B2- A second container (902 '), of substantially the same capacity as the first container (902), able to hold a vacuum, namely at a residual pressure of 0.1 millibar, said second container (902') being provided with a removable cover (904 ') with a vacuum gauge (905') and a vacuum plug connected to a vacuum pump.
• B3- A wringer (910) with a variable speed drum, and a pump for extracting the recovered film-forming liquid composition.
• B4- A drying device comprising:
  • a vertical drying column forming a cylindrical tube (920), able to be fed with air (hot or cold) from its lower part, and comprising:
    • at its lower part, a perforated lower grid (924) forming a support for the batch of plugs to be dried,
    • * at its upper end, a removable perforated upper grid (925) so as to let the hot or cold air, but to retain the plugs in the cylindrical vertical enclosure (920),
    • * at its upper part - just below said upper end - an upper lateral tubular duct (927) opening into said vertical enclosure through an opening, adapted to be held closed or opened by a movable flap (926), allowing the transfer of the caps to a packaging means, such as a net (929).
  • a turbine (922) for propelling air into a lower lateral duct,
  • an air heating means, such as electric heating resistors (923).
• B5- Centralized control means of these equipments, with recording of the parameters. These means were not represented on the figure 6 .
• B6 - A plug retention net capable of holding 100 caps per test. All equipment has been supplied commercially, with the exception of the B4 drying device which has been designed and constructed in the context of the invention.

Tests have also been carried out with a single-vessel device, as shown in FIGS. Figures 7a to 9c which makes it possible to carry out the four stages a) to d) of the treatment in the same reactor.

C) Generic implementation of steps a), b), c) and d) of treatment C1 - Step a) impregnation under pressure

In an autoclave or reactor vessel, a batch (900) of 100 so-called natural cork stoppers, namely crudes from a cork, is introduced into a suitable net (901) whose mesh size does not exceed the smallest size of the corks. washing, and a CP liquid composition (903) forming a bath, as shown in step 1 of the figure 6 , so that the plugs are totally immersed in the liquid CP composition in aqueous phase. After closing the lid (904), there was applied to the interior of the container a filtered and controlled air overpressure (905) of 3 bar (1 bar is 10 ⁵ Pa) for 5 minutes. At the end of this time, the compressed air was turned off and the inside of the vessel was allowed to return to atmospheric pressure. After having removed the lid (904), the net (901) was raised above the bath formed by the liquid composition (903), so that fillet and batch of plugs (900) drip for two minutes. minutes, so as to recover the excess of said liquid composition CP.

Note that the autoclave container was self-regulated in temperature around 38 ° C so as to maintain the viscosity of the liquid composition CP constant.

C2- Step b) vacuum desorption treatment

The batch of plugs (900) from impregnation stage a), still packaged in the net (901), was introduced into a second reservoir or reactor (902 ') resistant to depression, and then the lid (904). ') of said tank has been hermetically sealed. The inside of the tank was evacuated with a pressure controlled by a vacuum meter (905 ') of 1 millibar for 1 minute. Then the vacuum was turned off and this second tank (902 ') was put back to atmospheric pressure. This cycle was repeated 5 times. Then the lid (904 ') was removed and said batch of plugs (900') was removed from said second tank (902 '). The desorbed CP liquid composition (906) was recovered at the bottom of the tank (902 '). This small amount (906) of said CP liquid composition was extracted, either by gravity or with a pump, to then be filtered and recycled in the first step a) pressure impregnation.

C3- Step c) spinning

The batch of plugs impregnated with the emulsion polymers, still inside the net (901), was introduced inside a wringer (910) through the access window (911). The batch of plugs (900 ') was then subjected to alternating cycles of spinning and stirring, the net being of a volume slightly greater than that of the drum of the wringer. In the inner tub of the wringer, the polymer exudates which have been pumped back by the pump (912) were recovered to a recovery tank, to be filtered and recycled to the impregnation circuit.

C4-Stage of heat treatment (drying - cooking)

The batch of corks was extracted from the wringer directly with the aid of the net (901). The plugs were dumped from the net directly into a highly ventilated vertical duct furnace (920). The plugs were held by a calibrated wire mesh (924) above the low temperature heating system (923). The heating was increased to its set point and a vertical hot air stream ("A" circuit), from bottom to top, was circulated with a flow rate or flow rate that was high enough to maintain the plugs (921). levitation or suspension in the air. A second calibrated grid (925) in the upper part of the duct, retained any plugs lighter than the average of the batch, and under the upward pressure, would have risked escaping from the duct (920). The heating (923) was raised to its nominal level after a first solvent evaporation step. The plugs have been maintained in a levitation or flotation state in order to avoid the sticking effects between them, but also to avoid any excessive contact against the wall of the vertical duct (920). Advantageously, the walls of the vertical duct (920) have been surface-treated with PTFE deposition or any other material promoting sliding and limiting the risk of material accumulation of the coating object of the invention. When the heating cycle was completed, according to the times and temperatures, the air heating was stopped, so that fresh air was circulated instead of hot air, which allowed the batch of plugs (921) to cool to a temperature close to room temperature.

The air velocity has been lowered, for example to around 3 m / s, in order to force all the plugs to go down to the lower grid (924) and thus to allowing the flap (926) to move to obstruct the vertical duct (920) without being obstructed by possible levitation plugs and thus open the horizontal duct (927).

1. A - Mise en régime stabilisé de l'installation en température et vitesse d'air aux environs de 3 m/s.
2. B - Introduction d'un lot de bouchon dans la cheminée verticale précédemment ouverte.
3. C- Obturation de l'orifice d'introduction des bouchons à l'aide d'une grille de rétention de section calibrée, de façon à ne pas introduire de pertes de charges.
4. D - Ajustement de la vitesse de l'air entre 5 et 10m/s, en fonction de la taille et de la masse des bouchons, afin que ceux-ci restent en lévitation ou flottaison dans le volume de la cheminée, et pour éviter les contacts avec les parois et grilles d'obturation des conduits.
5. E - Coupure du chauffage et introduction d'air frais sur la même durée.
6. F - Réduction de la vitesse d'air aux environs de 3 m/s

A drying cycle comprises the following steps A to F:

1. A - stabilization of the installation at temperature and air velocity at around 3 m / s.
2. B - Introduction of a lot of plug in the vertical chimney previously opened.
3. C- Blanking of the plug introduction port with a retention grid of calibrated section, so as not to introduce losses of charges.
4. D - Adjustment of the speed of the air between 5 and 10m / s, according to the size and mass of the caps, so that they remain in levitation or floating in the volume of the chimney, and to avoid the contacts with the walls and gates shutter ducts.
5. E - Switching off the heating and introducing fresh air for the same duration.
6. F - Reduction of air velocity to around 3 m / s

• un premier cycle d'évaporation du solvant avec une température d'air de 50°C ± 10°C (dans certains modes de réalisation, cette température peut aller jusqu'à 70°C ± 10°C), mais qui ne comporte pas les étapes E & F,
• un second cycle comprenant une élévation de la température de chauffe, avec une température d'air de 80°C ± 10°C (dans certains modes de réalisation, cette température peut aller jusqu'à 90°C ± 10°C.

But the procedure chosen for the tests was the following for:

• a first solvent evaporation cycle with an air temperature of 50 ° C ± 10 ° C (in some embodiments, this temperature may be up to 70 ° C ± 10 ° C), but which does not include the E & F steps,
• a second cycle comprising raising the heating temperature, with an air temperature of 80 ° C ± 10 ° C (in some embodiments, this temperature may be up to 90 ° C ± 10 ° C.

C5 - Expulsion of corks and packaging

When the temperature of the treated and polymerized plugs has reached substantially the ambient temperature level, the batch of said plugs is expelled to the outside of the vertical oven, via a movable flap (926) closing off the main vertical duct , to direct them towards the exit through the horizontal duct thus released, with a speed of expulsion for example of 10 m / s. The plugs (928) are collected in an intermediate packing net (929), or in their final packaging.

The applicant was able to observe that it was necessary to comply with strict hygiene rules, in order to avoid any accidental pollution, whatever their origin, during this treatment cycle. In fact, the materials, equipment, tools and fluids used must remain under constant physico-chemical control, plus especially ensure the absence of bacteria, germs, to avoid any risk of contamination and cause organoleptic drift, or chemical changes of the bottled product.

In addition, the final packaging is advantageously made out of dust so as not to introduce external dust into the plugs conditioned for their end use.

D) The different tests carried out

Numerous exploratory tests have been carried out by the Applicant both with regard to the chemical nature of the starting CP liquid composition (903), as well as the process parameters for applying these compositions (903).

By way of information, the applicant has carried out the following tests which show, in the case of a supply of so-called natural corks, the necessity, according to the case, of the three stages of the treatment according to the invention (a, c and d of the process noted PR2), or of the four steps (a, b, c and d of the process noted PR1), with, in the following table, "1" if the corresponding step has been implemented, and " 0 "otherwise: Step a Step b Step c Step d observations 1 1 1 1 PR1 Stoppers according to the invention 1 1 1 0 Sticky caps not usable 1 1 0 0 Sticky caps not usable 1 0 0 0 Sticky caps not usable 1 0 ** 1 1 PR2 Stoppers according to the invention ** 1 0 0 1 Corks with very irregular surface coating 1 1 0 1 Corks with very irregular surface coating 0 * 0 1 1 Corks with very irregular surface coating * The plugs were impregnated without pressure.
** By cons, as already mentioned, especially in the case where supplying a batch of so-called plugged plugs, step b) vacuum desorption is no longer necessary to obtain plugs according to the invention.

D1 Tests relating to the liquid composition with the same treatment

Various liquid compositions CP (903) were prepared by mixing a composition or polymeric material P in the form of an aqueous dispersion, and a slip agent A, also in the form of an aqueous dispersion.

For each test, the nature and weight percentage of constituents P and A were indicated. Trial number (process) Nature and percentage of P Nature and percentage of A E1 (PR1) A21 - 100% 0% E2 (PR1) A21 - 95% A30 - 5% E3 (PR1) A21 - 90% A30 - 10% E4 (PR1) A21 - 80% A30 - 20% E5 (PR1) A21 - 95% A31 - 5% E6 (PR1) A21 - 90% A31 - 10% E7 (PR1) A21 - 80% A31- 20%

Many other additional tests have been carried out.

Thus, the E7 test was also carried out from a batch of so-called plugged plugs, according to the PR2 method.

Similarly, the test E1 was also performed by supplementing it with a subsequent application of a slip agent, which may correspond to the products A30, A31 or possibly A50.

Similarly, plugs with two impregnations were produced, a first with a liquid composition CP ₁ comprising 80% by weight of A 21 and 20% with a barrier mineral filler, and a second with a liquid composition CP ₂ comprising 80% by weight. weight of A21 and 20% of A31.

Similarly, plugs with two impregnations were produced, a first with a liquid composition CP ₁ comprising 80% by weight of A21 and 20% of a barrier inorganic filler, and a second with a liquid composition CP ₂ comprising 60% by weight. weight of A21, 20% of A31 and 20% of a dispersion of an elastomer.

In the treatments comprising two impregnations, each of these impregnations can be carried out according to the method PR1 and / or PR2, with all the possible combinations: PR1-PR1, PR2-PR2, PR1-PR2, PR2-PR1; "PR2-PR1" meaning that the first impregnation is carried out according to the method PR2 which does not comprise step b) vacuum treatment, while the second impregnation is carried out according to the method PR1 which itself comprises one.

Likewise, plugs were made with impregnation with a liquid composition CP comprising the Kuraray EVOH composition A22, reference AQ-4104, using each of the PR1 or PR2 method, said impregnation being followed by an application of at least one layer, and preferably two layers, of a Bluestar Silicone Fluid Dispersion A50, reference CAF 72582, said application being followed by drying under a pulsed air flow, the Applicant having observed that it was thus possible to advantageously obtain a silicone resin-based outer layer forming both a moisture barrier to protect the underlying moisture-sensitive EVOH layer, and a slip agent for cap.

E) Results obtained:

It should be noted that since the additional tests led to results comparable to the best results of tests E1 to E7, these results were not mentioned below.

1 - Visual aspect:

On the one hand, all the plugs of the same batch have a great homogeneity, and visual inspection of the same plug attestste that the composite skin formed on the surface of the plug is perfectly regular, taking into account the texture specific to the natural cork as a support, and gives the cork a natural cork appearance.

On the other hand, the cuts of these plugs, as illustrated on the Figures 2a to 2d have shown, by using a colored contrast agent, on the one hand, an excellent penetration of the film-forming liquid composition in the anfractuosities of the cork, and on the other hand, the formation of a "L + P" composite skin on the surface of the cork plug suberose tissue, as shown on the Figures 1b and 1c .

2 - Clogging and extraction force

Bottles have been closed with the plugs of the previous tests, using the usual method: using an instrumented commercial device to measure the vertical force, the plug is compressed radially and then introduced by mechanical push vertical in the neck of a bottle.

After storage for 26 days at 15 ° C, the caps were extracted with a device to measure the extraction effort.

• en ce qui concerne l'effort vertical de bouchage, on peut observer une plus faible dispersion des efforts avec les bouchons des essais E1 à E7 selon l'invention par rapport à l'essai témoin E0, comme on peut le voir en observant l'écart entre les courbes D et F des valeurs maximales et minimales. Les valeurs moyennes, qui se situent sensiblement autour de 30 daN pour l'essai E0, baissent assez nettement au-dessous pour nombre d'essais selon l'invention, par exemple les essais E3 à E6.
• en ce qui concerne l'effort d'extraction des bouchons, on peut noter, d'une part une grande différence selon la nature de l'agent glissant A : les résultats sont nettement supérieurs avec l'agent glissant A31. A noter les résultats de l'essai E7, remarquables à la fois par la faible dispersion des valeurs d'effort tant en bouchage qu'en extraction, et par le niveau de ces efforts, situés idéalement entre 20 et 30 daN. Par contre, des bouchons en liège naturel du commerce de longueur 45mm x 24mm de diamètre, traités aux silicones, ont donné des plages de valeurs à l'effort vertical de bouchage comprises entre 28 et 50 daN sur cols de bouteilles, verre sec. Les dimensions et profils des cols de bouteilles ayant au préalable été mesurés comme balayant le spectre des tolérances des normes CEN EN12726 :2000, GME 30 .05 et NF H35-100TR.

The results of these tests are grouped together in the table of the figure 3 :

• with regard to the vertical corking force, it is possible to observe a smaller dispersion of the forces with the plugs of the tests E1 to E7 according to the invention compared to the control test E0, as can be seen by observing the difference between the curves D and F of the maximum and minimum values. The average values, which are substantially around 30 daN for the E0 test, fall quite significantly below for a number of tests according to the invention, for example the tests E3 to E6.
• as regards the effort of extraction of the plugs, it can be noted, on the one hand, a great difference according to the nature of the sliding agent A: the results are significantly higher with the sliding agent A31. Note the results of the E7 test, remarkable both by the low dispersion of effort values both in capping and extraction, and by the level of these efforts, ideally located between 20 and 30 daN. On the other hand, corks of commercial natural cork of length 45mm x 24mm in diameter, treated with silicones, gave ranges of values at the vertical clamping force of between 28 and 50 daN on collars of bottles, dry glass. The dimensions and profiles of bottle necks were previously measured as sweeping the tolerance spectrum of CEN standards EN12726: 2000, GME 30 .05 and NF H35-100TR.

The plugs from the same batch were treated as the E7 test, and the results obtained with these plugs on the same bottles as before, gave ranges of values at the depression between 25 and 30 daN perfectly centered and with a standard deviation of 2.19, compared to a standard deviation of 11.71 in the case of commercial closures (test E0).

Concerning the extraction effort values, these were measured 26 days after capping, still on the same batch of labeled bottles.

The commercially treated natural cork bottles 45 x 24mm treated with silicones (test E0) have extraction values ranging from 20 to 30 daN with a standard deviation of 3.90, which is already remarkable because it is not rare to find on the market extraction values on natural cork fluctuating between 10 and 50 daN and even from 30 daN to more than 60 daN in the case of plugged corks.

In the case of the E7 test, the extraction values range from 23 to 30 daN with a relatively low standard deviation of 2.19.

3 - Dusts of plugs

At the end of the treatment according to the invention and the different subsequent capping and extraction operations, no trace of cork dust appeared, whereas under the usual conditions of use of natural corks treated paraffin or silicones or with the technical caps, significant amounts of cork dust are formed on the bottling lines, especially during the distribution and installation of said plugs.

The plaintiff has carried out the test recommended in the Charter of Corkers Corkers, carried out on 4 caps taken at random, on a lot. This Charter recommends that the amount of dust must be less than 1.5 mg for higher range caps and 2 mg for standard range caps. It has been found that with the plugs according to the invention, the amount of dust deposited is almost zero, and in any case at least ten times less than in the case of control plugs (test E0).

4 - Moisture content of corks

The Applicant has checked the internal hygrometry of the plugs obtained in the tests according to the invention, as well as the hygrometry at the start. All the caps of the tests have moisture content values, measured at 20 ° C, between 4 and 5%, values substantially identical to those of the initial plugs.

The plugs of the control test E0 also have a humidity level in the same range of values.

In addition, two types of tests were performed:

4A) Open air test:

The batches that were used for the sinking and extraction tests were taken back and measured after 9 months of storage in the corker's original packaging. Note that these plugs all include the hole of introduction of the tendrils of the corkscrew used during the extraction tests. The presence of this hole is a difference attenuator between the lots "A" natural cork trade and "B" impregnated with the treatment product of the invention.

The results were gathered on the table of the figure 4 .

The commercial natural cork stoppers, treated with silicones (E0), had an average humidity measured at the beginning of 4.4%, and a mean humidity, measured after 9 months, of 5.5%.

Commercial natural cork stoppers treated according to the invention (tests E1 to E7) had an average humidity initially measured after impregnation of 5.2%, and after 9 months, this average humidity was still 5.2%.

In view of this first series of results, it is clear that, unlike commercial natural cork stoppers, the corks treated according to the invention have absolutely not changed over time, despite the presence of the hole. spin at their upper end.

4B - Total immersion test

The two batches of test plugs E0 to E7 were immersed for 24 hours in a container containing water from the network. At the end of this period, and after a drying time of 24 hours in the open air, a new series of measurements was carried out and the following results appeared:

Commercial natural cork stoppers treated with silicones (test E0) had a moisture content initially measured ranging from 4.6 to 5.8% moisture. After immersion and drying, after 48 hours, the measured average humidity increased from 6.6% to 9.6% moisture.

The plugs of the tests E1 to E7 which are the subject of the invention had a humidity measured initially ranging from 4.7 to 5.4% of moisture. After immersion and drying, after 48 hours the measured average humidity ranged from 5.0 to 5.2% moisture.

In view of these results, the applicant notes that, unlike standard commercial plugs, corks treated according to his invention do not evolve over time, even in the presence of a liquid. The Applicant has concluded that the corks treated according to his invention can equip coated or uncoated bottles, which is not the case for standard commercial bottles, they must not under any circumstances remain upright, since said plugs must keep in constant contact with the liquid, otherwise the cork loses its moisture, becomes hardened and loses its elasticity, resulting in a loss of watertightness due to lack of contact force or springback, inside the cervix. the bottle.

5 - Permeability to oxygen

1. a) on approvisionne une bouteille bouchée par un bouchon en liège naturel et on découpe le corps de bouteille de façon à enlever sa partie inférieure. La découpe doit être franche et aussi plane que possible de façon à pouvoir déposer le haut de la bouteille (601) muni de son bouchon (600) sur une plaque plane (611), typiquement en inox, dans une zone où elle est perforée pour laisser passer deux conduits (613) et (614). La liaison entre l'extrémité basse de la bouteille et la plaque (601) en inox est rendue parfaitement étanche par dépôt d'un cordon (612) épais (typiquement 20 à 30 mm) en résine époxy. Par le conduit (613), on introduit à l'intérieur de la bouteille un gaz de pureté contrôlée, typiquement de l'argon pur ou de l'azote pur. Ce gaz est évacué par le conduit (614) qui est relié à un moyen permettant de mesurer la quantité d'atomes étrangers (par exemple des atomes d'oxygène) qui se sont introduits à l'intérieur de la bouteille (machines de type Oxtran). On met l'ensemble sous une enceinte (610), et on remplit cette dernière d'oxygène. Pour bien évaluer l'étanchéité du bouchage, il est nécessaire d'attendre plusieurs dizaines de jour, avant de commencer à mesurer la quantité d'oxygène qui s'est infiltrée à l'intérieur de la bouteille.

The sealing of a stopper does not only depend on the intrinsic barrier properties of the cork in contact with the interior of a glass tube. It is imperative to use a test representative of the actual sealing conditions of clogged bottlenecks. For this reason, the Applicant has used the following leak test (see figure 5 ):

1. a) a corked bottle is supplied with a natural cork stopper and the bottle body is cut so as to remove its lower part. The cut should be as clean and as flat as possible so that the top of the bottle (601) with its stopper (600) can be placed on a flat plate (611), typically made of stainless steel, in an area where it is perforated for pass two ducts (613) and (614). The connection between the bottom end of the bottle and the stainless steel plate (601) is made perfectly tight by depositing a bead (612) thick (typically 20 to 30 mm) of epoxy resin. Through the conduit (613) is introduced into the bottle of a purity controlled gas, typically pure argon or pure nitrogen. This gas is evacuated via the conduit (614) which is connected to a means making it possible to measure the quantity of foreign atoms (for example oxygen atoms) which have been introduced inside the bottle (Oxtran type machines ). The assembly is placed under a chamber (610), and the latter is filled with oxygen. To properly assess the tightness of the closure, it is necessary to wait several tens of days, before starting to measure the amount of oxygen that has infiltrated the inside of the bottle.

The applicant has carried out comparative tests of oxygen permeability of corks on bottles, in marketing conditions, which means with liquid inside said bottles. One batch of bottles was capped with standard commercial 45 x 24mm silicone-treated plugs (E0 test) and another batch of the same size, with corks treated with the material and the conditions of the pack. invention (tests E1 to E7).

Both types of corks were introduced into Bordeaux bottle necks. They were placed for 40 days in an enclosure containing oxygen.

• Essai E0 (lot bouché liège naturel du commerce): 0,00030 à 0,1227 cm³/24H/Bouteille.
• Essai E1 à E7 (lot bouché liège naturel traité selon l'invention) : 0,00005 à 0,0050 cm³/24H/Bouteille.

The analyzes were made with a dry gas (argon) and at room temperature. The following results of oxygen permeability were observed:

• Test E0 (cork lot cork natural commercial): 0.00030 to 0.1277 cm ³ / 24H / Bottle.
• Test E1 to E7 (cork lot natural cork treated according to the invention): 0.00005 to 0.0050 cm ³ / 24H / Bottle.

• d'une part que les bouchons témoins présentent une très grande dispersion des résultats (de 3.10^-4 à 0,12 cm³ O₂/jour, ce qui est considérable à comparer à la fourchette 5.10^-5 - 5.10^-3 cm³ O₂/jour, pour les bouchons selon l'invention, ce qui correspond à une dispersion des valeurs relativement faible.
• et d'autre part que les valeurs de perméabilité ont fortement baissé et qu'elles ont été divisées au moins par 10.

In view of these results, it appears:

• on the one hand that the control caps have a very large dispersion of the results (from 3.10 ^-4 to 0.12 cm ³ O ₂ / day, which is considerable to compare with the range 5.10 ^-5 - 5.10 ^-3 cm ³ O ₂ / day, for plugs according to the invention, which corresponds to a relatively low value dispersion.
• and secondly that the permeability values have fallen sharply and that they have been divided by at least 10.

6 - Liquid tightness test

Lot of ten bottles filled with wine and filled with corks of natural cork length 45 mm and diameters 24 mm (tests E0 to E7) were placed in an oven initially at 30 ° with temperature rise in increments of 5 ° C up to 60 ° C, the bottles being kept at the temperature of each stage for 4 days. At the end of this test, a visual examination and a weighing can detect a possible leak: a bottle is considered to have leakage if a weight loss of at least 2 g is observed.

Results: the control plugs of the E0 test exhibited a leakage rate of 5%, whereas the plugs of all the tests E1 to E7 according to the invention had a leakage rate of 0%.

7 - Measurement of the barrier effect to harmful molecules 7-1 Procedure:

1. a- selection of 15 natural corks,
2. b) Maceration of the stoppers in a 15% by volume aqueous ethanol solution of ethanol, acidified to pH 3.5 for three days at room temperature.
3. c- research and dosage of releasable haloanisoles

The haloanisole contents released in the hydroalcoholic solution were determined by SPME (Solid Phase Micro Extraction) and SBSE (Stir Bar Sorptive Extraction):

7-2 Demonstration of the barrier effect of the treatment according to the invention

Different batches of L1 to L5 plugs have been variously contaminated with haloanisoles. On each of these batches, a first sampling of 15 caps was used to determine the haloanisole content "before treatment", and on a second sample of 15 caps performed the treatment of the E7 test; then the haloanisole content "after treatment" was determined. The following table indicates the contents found expressed in ng / l (nanogram per liter): Before treatment After treatment Efficiency in% L1 85.9 15.7 82 L2 38.1 7.0 82 L3 22.7 1.9 92 L4 19.3 1.5 92 L5 8.2 0.7 91

It can be seen from this table that the treatment according to the invention can be effectively applied to relatively polluted plugs with a haloanisole content of about 23 ng / l, given that the detection threshold is 2 ng / l.

Moreover, when it is known that the usual haloanisole contents of the so-called natural plugs or so-called plugged commercial is around 10 ng / l, it is clear that the invention can ensure for corks a haloanisole content lower than detection threshold of 2 ng / l.

8 - Sensory analysis tests

• au moins 80% des bouchons en liège naturel du commerce (essai E0), ont produit des odeurs et des goûts de bouchons rendant l'eau difficilement buvable.
• 100% des bouchons traités avec le matériau et selon le traitement de l'invention (essais E1 à E7) n'ont induit aucune déviation organoleptique détectable olfactivement ou à la dégustation de l'eau.

The Applicant has also carried out tests of sensory and taste analysis of water, in which plugs had been immersed beforehand for at least 24 hours, each in a glass of water deemed organoleptically neutral. It appeared that after a quantity of significantly representative tests:

• at least 80% of the commercial natural cork stoppers (test E0) produced odors and tastes of corks making the water hard to drink.
• 100% of the corks treated with the material and according to the treatment of the invention (tests E1 to E7) did not induce any detectable organoleptic deviation olfactory or tasting water.

F) General conclusions

All the checks and tests carried out comparatively, and grouped under the preceding 8 items, have shown that the corks obtained by the treatment according to the invention have properties always superior to those of the control corks.

The invention makes it possible to economically produce a large variety of corks with properties and performances adapted to the particular requirements of each type of wine to be bottled, in particular by adding to said liquid composition of all kinds of additives, such as TiO ₂ , SiO ₂ , SiOx, talc, clays, kaolin, barium sulfate.

LIST OF REFERENCES

Cork............................................... ........ 100 Bottle................................................. ....................... 101 Overcap Capsule ......................................... 102 Liquid in the bottle ......................................... 103 Cell structure of cork .................................. 200 Anfractuosity of cork ............................................... 201 "L + P" composite skin ........................................... 204 ½ Left cup of cap ................................ 300a ½ Straight cut of cap .................................... 300b Composite skin outside ....................................... 301 Skin or inner lining (with tracer) ..... 304 Bottle portion ............................................... ..... 600 Collar of the bottle .............................................. ........ 601 Waterproof envelope ................................................ ...... 610 Waterproof metal plate ........................................... 611 Cord of waterproof material .................................... 612 Gas supply tube ............................................ ... 613 Gas outlet pipe ............................................. ... 614 Reactor wiper ................................................ ....... 800 Spherical wiper reactor ................................... 800a Cylindrical wiper reactor .................................. 800b Frustoconical evaporator reactor ................................ 800c Outside wall ................................................ ............ 801 Central basket with perforated wall ............................... 802 Central tree ................................................ .................. 803 Central and perforated hollow shaft .................................. 803 ' Air supply under pressure P ₁ ................................. 804 Vacuum outlet for pressure P ₂ ................................. 805 Upper hatch of 801 .......................................... 806 Lower hatch of 801 ............................................. 807 Hatch of 802 ............................................... .................. 808 Evacuation of hot air ............................................. ..... 809 Supply & drain hose ................................... 810 Stoppers to be treated - batch of corks ......................... 900 Natural cork stoppers .............................................. 900a Clogged corks ........................................... 900b Retention net of plugs ...................................... 901 Tank or pressure vessel ............................ 902 Fluid liquid composition ............................................... .... 903 Tank cover ............................................... ........ 904 Measurement of applied pressure ..................................... 905 Tank under vacuum ............................................... .. 902 ' Liquid composition ................................................ ................ 903 ' Tank cover ............................................... ........... 904 ' Vacuum measurement applied .............................................. ......... 905 ' Desorbed liquid composition ............................................... . 906 Spinner ................................................. ................................... 910 Access port .............................................. ..................... 911 Polymer extraction pump ................................... 912 Vertical furnace .............................................. ........... 920 Caps to dry and cure ............................. 921 Turbine................................................. ............................... 922 Heating resistors ................................................ .. 923 Lower grid ................................................ ................. 924 Top grid ................................................ ............... 925 Shutter................................................. ..................................... 926 Horizontal evacuation pipe ..................................... 927 Ready-to-use treated cap ................................... 928 Packing net ............................................... .... 929

Claims (15)

1. Treatment of naturel cork stoppers (900) successively comprising the hollowing steps a, c and d:

   a) a batch of a plurality of so-called natural corks (900a) is provided and said batch is impregnated in a liquid composition CP (903) comprising at least one polymeric maternal P, at a pressure P₁ greater than atmospheric pressure P_A, so as to obtain a so-called impregnated batch,

   c) then, said impregnated batch is dried, so as to obtain a so-called dried batch,

   d) finally, said dried batch is subjected to a heat treatment,
   so as to obtain a batch of so-called treated corks (928), each cork (928) having a "composite skin"(204, 301, 304) made of cork L impregnated with polymeric material P, represented symbolically by "L+P".
2. Treatment of natural cork stoppers (900) according to claim 1 further comprising a vacuum treatment step b), inserted between said steps a) and c) so as to successively obtain the following steps a) to d):

   a) a batch of a plurality of so-called natural corks (900a) is provided and said batch is impregnated in a liquid composition CP (903) comprising at least one polymeric material P, at a pressure P₁ greater than atmospheric pressure P_A, so as to obtain a so-called impregnated batch,

   b) then, said impregnated batch is vacuum-treated at a pressure P₂ <P_A, so as to obtain a vacuum-treated batch,

   c) then, said vacuum-treated batch is dried, so as to obtain a so-called dried batch,

   d) finally, said dried batch is subjected to a heat treatment.
3. Treatment according to any of claims 1 to 2 wherein, in step a), said batch of corks (900a) is immersed in a first pressure-resistant receptacle (902) containing said liquid composition (903), and said receptacle (902) is pressurized with an air pressure P₁ between 2 and 6 bar and preferably from 3 to 5 bar, said air pressure P₁ being applied inside said first receptacle (902) for a time between 1 and 15 minutes and preferably from 3 to 10 minutes.
4. Treatment according to any of claims 2 to 3 wherein, in step b) of the treatment, said impregnated batch is vacuum-treated, inside a receptacle suitable for withstanding a vacuum (902'), with a pressure P₂ from 0.1 to 4 mbar, and preferably from 0.5 to 1.5 millibar.
5. Treatment according to any of claims 1 to 4 wherein, in step c) of the treatment, after venting, the vacuum-treated batch of corks, once introduced into a drier (910), is dried in cycles, each cycle comprising a drying phase lasting 0.5 to 5 minutes preferably between 1 and 3 minutes, with a number of cycles between 1 and 5 and preferably between 2 and 3, and a cork moving phase being inserted between each drying phase, lasting between 3 seconds and 1 minutes and preferably between 5 seconds and 30 seconds, and during which the corks change position and place inside the drum of the drier (910).
6. Treatment according to any of claims 1 to 5 wherein, in step d) of the treatment, after having removed the batch of corks (921) from the drier (910) in step c) of the treatment, said batch of corks (921) is treated, in a chamber (920), by a hot air stream at a velocity between 3.0 and 20.0 metres per second and preferably between 5.0 and 10.0 metres per second, so as to form said heat treatment, said heat treatment particularly being intended to remove a solvent from said liquid composition CP, when said liquid composition CP comprises a solvent.
7. Treatment according to any of claim 1, 2, 3, 4 and 6 wherein, in step a) of the treatment, a batch of so-called plugged corks (900b) is provided and the vacuum treatment step b) is withdrawn.
8. Treatment according to any of claims 1 to 7 wherein said liquid composition CP (903) comprises, in addition to said polymeric material P, at least one additive A intended to promote sliding of the cork in contact with glass, such that said treated cork has a "skin" having a composition represented symbolically by "L+P+A".
9. Treatment according to any of claims 1 to 8 wherein said liquid composition CP (903) forms an emulsion or an aqueous phase dispersion of at least one polymeric material P from among the polymeric materials :

   a) approved for food contact,

   b) suitable for forming a barrier to said harmful molecules,
   said polymeric material P being preferably an emulsion of acrylic polymers in aqueous medium or an aqueous compositions based on EVOH, a copolymer of ethylene and vinyl alcohol,
10. Treatment according to any of claims 1 to 9 comprising:

    a) a so-called first sequence of at least steps a), c) and d), from said first polymeric liquid composition CP₁, typically formed by said liquid composition CP comprising said polymeric material P, so as to form a so-called first impregnation,

    b) and a supplementary treatment comprising, for example a so-called second sequence of at least steps a), c) and d), from a so-called second polymeric liquid composition CF₂, at least said second polymeric liquid composition CP₂ comprising said additive A intended to promote the sliding of said corks, so as to form a so-called second imprégnation, such that said treated cork has a composite "skin" having a composition represented symbolically by "L+P / A".
11. Treatment according to any of claims 1 to 10 wherein said liquid composition CP (903), CP₁ or CP₂ comprises an elastomeric material E chosen from: butyl rubber, nitrile rubber, thermoplastic elastomers such as SIS (styrene isoprene styrene), SBS (styrene butadiene styrene), SEBS (styrene ethylene butylenes styrene), MS polymer (Modified Silicone polymere) or PDMS (Polydimethylsiloxane).
12. Treatment according to any of claims 8 to 11 wherein said additive A for promoting sliding of the cork in contact with glass is a wax in anionic emulsion, typically based on paraffine wax or carnauba wax, or a silicone resin when said first polymeric liquid composition CP₁ comprises said aqueous composition based on EVOH, so as to coat said polymeric material P based on EVOH with a layer forming both a water barrier and a sliding agent, said additive A optionally being a constituent additive A₂ of said seconde polymeric liquid composition CP₂, said second polymeric liquid composition being devoid of EVOH in this case.
13. Treatment according to any of claims 1 to 12 wherein said liquid composition CP (903) comprises a micronised mineral filler B forming a barrier, particularly to gas diffusion, said mineral filler being chosen from: silica SiO₂, a silicon oxide SiO_x (where x < 2), titanium oxide TiO₂, micronised clay, kaolin, barium sulphate.
14. Cork stopper obtained musing the treatment according to any of claims 1 to 13, characterised in that it has, on the entire accessible surface thereof, outer surface and inner surface of the cavities or indentations of said corks, a surface area of cork L, comprising a penetration of said polymeric material P in the mass thereof with an incorporation of said polymeric material P with the cork, such that said treated cork has a composite skin (204, 301, 304) having a composition represented symbolically by "L+P", said composite skin (204, 301, 304) having a thickness E of at least 10 µm and up to 1 mm, according to the local hardness or porosity of the natural cork or the constituents thereof, and optionally characterised in that said surface area of cork L forming said composition skin (204, 301, 304) comprises, in addition to the incorporation of said polymeric material P in the cork and the incorporation of said addictive A, the incorporation of at least one adjuvant chosen from: a micronised mineral filler B forming a barrier, particularly to gas diffusion, an elastomer resin E.
15. Cork stopper according to claim 14 wherein said surface area of cork L forming said composite skin (204, 301, 304) comprises, in addition to the incorporation of said polymeric material P in the cork, the incorporation of said addictive A for promoting sliding of the cork in contact with glass, such that said treated cork has a composite skin having a composition represented symbolically by "L+P+A" or by "L+P / A" according to whether said addictive A is incorporated in said polymeric material P or coats said polymeric material P, and optionally characterised in that said surface area of cork L worming said composite skin (204, 301, 304) comprises, in audition to the incorporation of said polymeric material P in the cork and the incorporation of said addictive A, the incorporation of at least one adjuvant chosen from: a micronised mineral filler B forming a barrier, particularly to gas diffusion, an elastomer resin E.

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