EP3981564A1 - Method for manufacturing cylindrical bodies from cork sheets and end product obtained through said method - Google Patents

Abstract

The present invention refers to a new process for the manufacture of cylindrical cork bodies and to the final product resulting from this new process for the manufacture of stoppers for beverages (for example: carbonated wines, still wines, beers, etc.) or washers which are used in multi-piece cork stoppers and which rests on the lamination of a natural cork board after being fired and flattened (1), with blades with a thickness of between 0.06 mm and 2 mm (2), the individual cleaning of each slat (3), the gluing of the thin slats with specific edible glues used in the cork sector, which after being selected (4), are glued in such a way that the natural irregularities of the cork are shifted, making it possible to compose a homogeneous cork parallelepiped (5). Then, the parallelepiped composed of microlayers of cork is cut into slices and cased according to the traditional process of manufacturing natural corks or discs. The casing of the production process can be carried out parallel to the direction of the laminated sheets (6), perpendicularly (7) or obliquely (8). The stopper and the washers resulting from this new manufacturing process have all the physical and visual characteristics of cork in the natural state.

Description

Introduction

The beverage market, particularly the still wine and carbonated wine markets, predominantly uses cork stoppers, commonly referred to as cork stoppers. The use of cork meets the technical specifications required by the market, whether in terms of its sealing capacity, or the visual appearance produced by cork stoppers and which give a real guarantee of quality to the beverage.

• l'uniformité visuelle du bouchon ;
• l'uniformité dans le comportement physique du liège en tant que bouchon ;
• l'absence de contaminants gustatifs (par ex. : Le trichloroanisol et d'autres substances volatiles)

Since cork is a natural product, it poses difficult challenges to overcome when manufacturing stoppers, namely:

• the visual uniformity of the cork;
• uniformity in the physical behavior of cork as a stopper;
• absence of taste contaminants (e.g. trichloroanisol and other volatile substances)

The big challenge for the industry is to manufacture a cork stopper for the markets that already use it, but clearly overcoming the 3 points mentioned above.

State of the art:

Cork is a natural product derived from the cork oak composed of several microscopic hollow cells and harmonic cell walls that constitute a 100% natural tissue with unparalleled elasticity and rebound capacity. These particular characteristics of cork are mainly used for the production of cork stoppers.

The traditional method of making cork stoppers presupposes the extraction of pieces of natural cork from cork oaks. These pieces being extracted from a tree, they have an irregular concave shape (Fig.l). So that they can be used later in the manufacture of corks, the pieces of cork are subjected to a boiling and flattening treatment, which makes it possible to create flat and rectangular cork planks, in strips, which are then cut into slices of appropriate thickness and pierced using a tubing machine, producing cylindrical cork bodies.
These cylindrical bodies then move on to the normal finishing processes, ie grinding, washing, surface treatment and marking. It is the most classic cork stopper production process, with the least technological development in the sector, giving rise to the so-called natural stopper.

This traditional method of producing cork stoppers is the most appreciated and used for the highest quality wines, as it naturally allows the use of the particular characteristics of cork, tightness and better preservation of flavors. original.

It turns out that the production of natural cork stoppers is insufficient to meet market needs. In addition, natural cork stoppers also have their flaws: they are very heterogeneous because they contain porosities and cracks or hollows, which cause very visible and variable imperfections that can have direct implications on the mechanical behavior of the cork stopper. in the bottle, which can cause leaks and influence the organoleptic neutrality required for corks in direct contact with the liquid contained in the bottles. This type of undesirable reaction that can affect the aroma of wines is directly linked to the significant increase in the quantities of 2,4,6 trichloroanisol (TCA). This type of contamination results from the interaction of certain fungi or parasites existing in the cork, such as Armillariamellea, and has a direct influence on the aroma of wines.

In order to meet the needs of the market and the disadvantages of natural cork, technical corks have appeared.

Technical cork stoppers consist of several pieces of cork and can include parts or granules of cork. The different typologies differ according to the organization and the number of pieces, with or without a granular component.

• L'extrusion réactive continue ;
• Le compactage - réaction en moule fermé ;

Technical corks can be agglomerated corks; multi-piece caps with pellets and multi-piece caps that can result from two manufacturing processes:

• Reactive extrusion continues;
• Compaction - reaction in a closed mould;

The technical stopper manufactured through a continuous reactive extrusion process is based on the passage of cork granules previously moistened with a polymer, through a tubular section, which under the effect of temperature produces a stem of cork granule . This rod is then cut according to the desired size of the cylinders, which then, through the same finishing processes, will become the final cap.

The technical cork manufactured using the compaction process (reaction in a closed mould) is based on the injection of granulated cork pre-moistened with a polymer. The injection is made in an individual mold which, under the effect of the temperature, will produce the cylindrical body in cork agglomerate which, after the normal finishing processes, will become the cork stopper. Individual compaction of the molds can be done by adding washers simultaneously, depending on the desired end cap (eg: 1 + 1 cap, with two washers at the end of the cap).

Agglomerated stoppers are made up of cork grains, obtained from the waste from the production of natural cork, and which can be characterized according to the different diameter dimensions of the cork grains which are then bound with reactive glues. Stoppers with an average grain size between 2 mm and 8 mm have less quality than cork stoppers whose the average grain size is between 0.25 mm and 2.5 mm.

According to patents EP0496687 and EP2099689 , we know of two production processes for agglomerated corks.

In the first case, the cork is composed of three components: a woody vegetable material which, for the manufacture of the stopper, is preferably a natural cork reduced to powder; a closed cell plastic; a binder which, for the manufacture of stoppers, will preferably be a food-grade adhesive of the polyurethane or acrylic type.

In the second case, the stopper is produced with two types of cork granules, with complementary characteristics and for which the bond is established through an individual molding process.

The main disadvantage of this type of stopper is that the liquid contained in the bottle is in contact with the cork granulate, but also with its binder, which can influence the aroma and the quality of the liquid inside. the bottle. Although these are corks with a low production cost, they are considered lower quality corks and are therefore only used for lower quality wines.

As a solution to these drawbacks mentioned for agglomerated corks, technical multi-piece pellet corks have appeared.

Granulated multi-piece technical corks are composed of one or more pieces of cork, usually washers, and a granulated component or body, differing between them depending on the arrangement of the parts in relation to the pellet.

According to patents EP0481155 and EP0100302 we are aware of two processes for manufacturing granulated multi-piece stoppers, in which the process for manufacturing a cork stopper consisting of a main body of granular cork and at least one end piece of natural cork with the pores arranged in a direction perpendicular to the axis of the stopper.

But these plugs also have drawbacks, such as, for example, the bonding of two materials with different characteristics, where one offers little intrinsic variability and heterogeneity typical of a natural material and not the other, which which means that the homogeneity of the behavior of the stopper as a shutter is not entirely satisfactory.

Still in the category of technical corks, we have the multi-piece technical corks which are made of 2 or more pieces of cork, without any granular component that differ in their organization in the constitution of the cork.

According to patents EP1393869 and EP2093032 , we know of two processes to make very identical multi-piece plugs.

In the first case, the manufacturing process supposes the bonding of several non-consecutive washers of the same cork panel with the interfaces between the washers substantially perpendicular to the veins of the plug and where the plugs are drilled in the direction of the growth rings, which gives a final plug composed of 3 cylindrical layers.

In the second case, the manufacturing process is very similar to the previous one, but in the present case, the stopper is composed of two or more substantially cylindrical natural stopper elements connected by their bases after having been selected, inspected and positioned according to the result of the inspection to form each abutment and where the veins of the abutment elements are in different angular positions with respect to their longitudinal axes.

As with the other types of technical caps, they also have their drawbacks, such as their external appearance because we can distinguish the transverse bands that overlap and which correspond to the different layers that make up the cap.

In the range of technical caps, we also have the international patent WO2011033485 whose stopper resulting from this invention results from the manufacturing process which consists in gluing a set of 6 to 7 natural cork washers of 6 mm to 8 mm.

The present invention therefore consists in the manufacture of cylindrical bodies with microlayers similar to the aforementioned manufacturing processes, but whose cylindrical bodies resulting from the new manufacturing process have a set of advantages which differentiate them from all the existing caps on the market, such as we will see it.

We can therefore conclude that for all the corks known to date, their composition and their manufacturing process have drawbacks, including for the natural cork.

The major challenge in the cork stopper market is to be able to produce a stopper that retains the advantages of natural cork, getting as close as possible to its physical characteristics, guaranteeing greater organoleptic neutrality and a physical homogeneity impossible to guarantee with all the other production methods, even with the natural cork, while having reduced production costs and without the known drawbacks of technical corks. This is precisely the main objective of this invention.

Description of figures

• Fig. 1 - Shows the piece of natural cork after boiling, resting and stacking, giving it a flat shape (1), showing the growth lines and irregularities of the cork visible throughout the piece.
• Fig. 2 - shows the visual appearance of the flat piece of cork (1) after the lamination process into cork sheets with a thickness between 0.06 mm and 2 mm (2);
• Fig. 3 - Shows the piece of cork after the 0.06 mm to 2 mm thick blades (2) have been individually cleaned (3), classified by levels of irregularity (4), rearranged and glued together with the irregularities of each blade offset and pressed, to create a parallelepiped with total physical homogeneity (5) visible over the entire piece;
• Fig. 4 - Shows the parallelepiped resulting from the bonding of the blades from 0.06 mm to 2 mm thick (2) and the shape of the cutting strips of cork for later casing, showing the physical homogeneity resulting from gluing
  (5) along the part;
• Fig. 5 - Shows the parallelepiped resulting from the gluing of the 0.06 mm to 2 mm thick strips (2) and the shape of the cutting of the cork strips for subsequent casing, showing the physical homogeneity resulting from the gluing.
  (5) along the entire piece and the cylindrical body resulting from the casing carried out parallel to the bonding of the blades (6);
• Fig. 6 - Shows the parallelepiped resulting from the gluing of the 0.06 mm to 2 mm thick blades (2) and the shape of the cutting of the cork strips for subsequent casing, showing the physical homogeneity resulting from the gluing
  (5) along the entire piece and the cylindrical body resulting from the casing carried out parallel to the gluing of the blades (7);
• Fig. 7 - Shows the parallelepiped resulting from the gluing of the 0.06 mm to 2 mm thick strips (2) and the shape of the cutting of the cork strips for subsequent casing, showing the physical homogeneity resulting from the gluing
  (5) along the entire piece and the cylindrical body resulting from the casing carried out parallel to the bonding of the blades (8);

Detailed description of the invention

The present invention is a new process for the manufacture of cylindrical cork bodies with microlayers characterized by an unequaled physical homogeneity with respect to natural corks and technical corks known on the market and which is done by obtaining concave and elongated natural cork planks in the tree and with the growth lines of the cork arranged perpendicularly to the radial direction of the tree.

The natural cork planks are subjected to a process of boiling in clean boiling water, the duration of which can vary between 70 and 90 minutes and at a temperature between 80 and 100°C, depending on the characteristics of the cork planks. natural. Then comes the flattening phase resulting from the firing and subsequent stacking of the boards to give the piece of cork a flattened shape. For a period that varies between 24h and 72h, the cork is left to rest and then we move on to the drawing phase.

For the present invention, the cork planks are fired at a temperature of 90°C for 90 minutes.

The cooking phase of the cork is important because it is thanks to it that the cork becomes more regular and that its volume increases. It is also an effective mechanism to reduce microflora and consequently improve the internal structure of cork.

The firing process used in the present invention is that traditionally used for firing natural cork planks.

• d'une plaque circulaire sur laquelle les planches de liège sont fixées à des plaques moletées ;
• d'un couteau rotatif.

The cutting of the already flat cork planks is carried out using a machine for the cutting of cork sheets composed of:

• a circular plate on which the cork planks are fixed to knurled plates;
• with a rotating knife.

During the lamination process, the circular plate with the fixed cork planks successively passes through the rotating cutter which cuts the cork planks in thicknesses ranging from 0.06 mm to 2 mm (2).

The lamination method of the present invention and the mechanical equipment used do not represent in themselves a technical feature of the present invention, since they are known methods for the lamination of cork boards. The technical characteristic lies in the reduced thickness of the blades obtained by the rolling process from 0.06 mm to 2 mm (2) and their use in the composition of parallelepipeds of cork for the casing of cylinders with microlayers used as obturators of beverage.

Then comes the cleaning of each blade individually (3), the reduced thickness of the cork blades between 0.06 mm and 2 mm (2), which differs from all other production processes known to date, allows a better cleaning, since it is carried out individually on each side of the blades, allowing almost total neutrality from an organoleptic point of view. Cleaning consists of deodorizing and disinfecting contaminants. If we take into account the reduced thickness of the blades between 0.06 mm and 2 mm (2) that will constitute the parallelepiped, it is easy to understand that the cleaning surface in volume is much greater than that of the washers whose l thickness is much greater than the maximum thickness of 2 mm that the blades can reach of the invention.

The cleaning process used for the present invention does not represent in itself a technical characteristic of the invention, because the process which offers the best results known on the market will always be used, what characterizes the present invention is the fact that the cleaning is carried out individually, blade by blade (3), ensuring that the surface to be sanitized in volume is much larger than for the natural cork and the multi-piece corks.

The cork strips produced are classified by quality of the material, either by visual selection or by mechanical selection using an electronic device (Scanner) (4), depending on the levels of irregularities.

In this way, it is possible to create a uniform cork quality when building the parallelepiped compared to a natural cork board.

When the blades have been obtained, they are glued using a binder for food use. We will always use at the time of application the binder that is used on the market at that time and that combines the best qualities. The gluing of the different slats is done according to the classification obtained (4) and so that the pores resulting from the lines of growth and the natural irregularities of the cork are shifted in the interfaces of each of the slats preventing them from communicating with each other. This method of gluing in which the irregularities of the cork are staggered between them in order to create a physically homogeneous parallelepiped (5) represents a real innovation.

In this way, a physical homogeneity is obtained that is impossible to achieve thanks to the methods already known from all the other patents and natural corks, where one of the disadvantages pointed out is precisely the impossibility of eliminating the irregularities of the cork.

Once glued, the blades are pressed, the pressing can be done with light or strong pressure and can be done hot or cold. The pressure of the pressing will have a direct impact on the final elasticity of the product, for this reason a light pressing is carried out in the present invention which will guarantee a higher available elasticity and consequently better levels of tightness of the cylindrical bodies produced by this new process.

The bonding and pressing process used do not represent in themselves a technical characteristic of the invention, because we will always use at the time of application the binder and the press which are used on the market at that time and which bring together the best qualities, the particularity lies in the fact that when gluing the slats of reduced thickness from 0.06 mm to 2 mm (2), we manage to effectively eliminate the irregularities of the cork by gluing each slat by shifting the irregularities of the cork of each blade (5), thus guaranteeing a greater and better density compared to the existing corks on the market, whether natural or technical.

Indeed, comparative studies carried out on the corks resulting from the present invention show that their density, always associated with the elasticity of the cork and the levels of glue used in the production, achieve unprecedented results compared to existing corks, since it no need to use large amounts of glue.

Cork for natural stoppers (of good quality) has a specific weight or density of the natural stopper between 170 and 190 kg/m3 => 180 kg/m3 +/- 10 kg/m3.

For micro-granular technical closures, the specific weight or density is between 280 and 300 kg/m3 => 290 kg/m3 +/- 10 Kg/m3.

For corks resulting from the new production method, the specific weight or density is between 160 and 280 kg/m3 => 220 kg/m3 +/-60 Kg/m3.

As we can see, the cylindrical bodies resulting from the present invention approach the values of natural corks, and they should even exceed them.

From the blades obtained through gluing, a parallelepiped is obtained which can be cut according to the dimensions that allow a better optimization of the casing (6,7 and 8) in relation to the desired final product, to the production of microlayer plugs or washers for technical caps. This optimization is defined according to the dimensions of the cork cylinder that will be produced and the direction of tubing can be modified according to the desired product. The cork parallelepipeds can reproduce the strips used for traditional perforation in the tubing machines usually used in the manufacture of natural corks or in the traditional tubing machines for the production of washers.

Other casing techniques can also be developed to optimize industrial yield in the production of plugs or washers.

The parallelepipeds resulting from the gluing of cork strips with a thickness of between 0.06 mm and 2 mm (2) are composed of an average number of strips varying according to the type of cylindrical body that one wishes to produce. In a stopper used for sealing with a length of 45 mm and a diameter of 25 mm (normal size of stoppers for sealing fortified wines), the parallelepiped may be composed of an average of blades ranging from 416 to 12 (9). In a washer used for the manufacture of technical corks (normal size washers used for sparkling wine corks) with a length of 6.4 mm and a diameter of 30 mm, the parallelepiped can be composed with an average of blades which vary from 500 to 15 (10).

The cylindrical bodies resulting from the new process are made up of several cork blades which are positioned with respect to the axis of the cylinder according to the direction of the casing and which can be carried out parallel to the direction of the laminated sheets (6), perpendicularly (7) or obliquely (8) with respect to the axis of the piece, depending on the type and the cylindrical body that is to be obtained.

As it is possible to tube in any direction, it is possible to obtain greater profitability from the whole piece of cork.

For the production of corks intended for still wines, the preferred casing process is that done in the direction parallel to that of the laminated sheets (6), thus a visual effect similar to that of natural cork is obtained.

Once cased, the corks are subjected to the usual finalization, sanding and finishing processes, without resorting to cosmetic imprints, widely used in technical corks to approximate the visual image of natural corks.

For the production of the washers that will serve as components for technical stoppers, it is preferable that the cork blades are positioned perpendicular to the axis of the cylinder, that is, along its length (7), thus producing a visual effect similar to washers made from a piece of cork (natural washer).

Characteristics of the cylindrical bodies (stoppers or washers) obtained by the process of the present invention (the end result of the process is the manufacture of microlayer cork cylinders):
All the characteristics of the following cylindrical bodies result from the fact that, in the method of the present invention, the cork blades used have such a small thickness, between 0.06 mm and 2 mm (2), allowing to clean a greater quantity of cork, cleaning carried out individually, blade by blade (3) taking into account the large quantity of cork blades used for the manufacture of cylindrical bodies (9 and 10), as well as the almost complete elimination of irregularities and characteristic pores of natural cork when choosing the slats (4) and gluing the slats (5).

• Une homogénéité totale et une similitude visuelle (bouchons ou rondelles) par rapport à un bouchon naturel, en raison du volume élevé de liège utilisé pour sa composition, résultant du collage de feuilles de liège à faible épaisseur ;
• Une homogénéité physique totale, concernant la densité par rapport aux bouchons produits sur le marché actuel, selon une étude de marché comparative déjà révélée ;
• Une homogénéité physique totale le long du corps cylindrique en termes de densité, de porosité et d'élasticité par rapport au bouchon naturel, dont l'homogénéité physique est très variable en raison des caractéristiques naturelles du liège ;
• Une uniformité du standard moyen de qualité, sans avoir recours aux empreintes cosmétiques utilisées dans tous les bouchons techniques, grâce à la taille réduite des lames ;
• Une neutralité d'un point de vue organoleptique grâce au nettoyage d'une plus grande surface de liège (désodorisation et désinfection) car les traitements sont administrés lame par lame, garantissant un grand volume de nettoyage de surface ;
• Des bouchons fabriqués à partir de liège de toutes les classes et de tous les calibres, sans restriction similaires à celles des autres obturateurs de liège ;
• La possibilité de fabriquer des bouchons de liège de toutes tailles, y compris d'autres composants (par exemple : des rondelles en liège) avec une homogénéité totale alors que dans la fabrication traditionnelle du bouchon en liège naturel ou du bouchon technique, le produit final est très hétérogène ;
• L'optimisation du tubage car il peut être tubé dans le sens longitudinal, perpendiculaire ou oblique par rapport à l'axe de la pièce, en fonction du type et du corps cylindrique que l'on veut obtenir ;
• Un faible coût de production.

Indeed, the cylindrical bodies resulting from the present invention differ from those already known on the market. because they guarantee:

• Total homogeneity and visual similarity (corks or washers) compared to a natural cork, due to the high volume of cork used for its composition, resulting from the bonding of thin cork sheets;
• Total physical homogeneity, in terms of density, compared to closures produced on the current market, according to a comparative market study already revealed;
• Total physical homogeneity along the cylindrical body in terms of density, porosity and elasticity compared to the natural cork, whose physical homogeneity is highly variable due to the natural characteristics of cork;
• Uniformity of the average quality standard, without resorting to the cosmetic imprints used in all technical corks, thanks to the reduced size of the blades;
• Neutrality from an organoleptic point of view thanks to the cleaning of a larger surface of cork (deodorization and disinfection) because the treatments are administered blade by blade, guaranteeing a large volume of surface cleaning;
• Stoppers made from cork of all classes and calibers, without restrictions similar to those of other cork stoppers;
• The possibility of manufacturing cork stoppers of all sizes, including other components (for example: cork washers) with total homogeneity whereas in the traditional manufacture of the natural cork stopper or the technical stopper, the final product is very heterogeneous;
• The optimization of the casing because it can be cased in the longitudinal, perpendicular or oblique direction with respect to the axis of the part, depending on the type and the cylindrical body that you want to obtain;
• A low cost of production.

Claims (9)

Process for manufacturing cylindrical cork bodies comprising the following steps: a) Cooking of the natural cork plank between 70 and 90 minutes at a temperature between 80°C and 100°C and flattening resulting from the cooking (1); b) Rest of the cork for a period of 24h to 72h; c) Rolling the cork board using a cork slicing machine, into strips of thin cork between 0.06 and 2 mm (2); d) Individual cleaning of each side of the sheet resulting from rolling (3); e) Classification of blades according to the quality of the material (4); f) Bonding with application of binder suitable for food use and pressing so that the growth pores of the blades are oriented perpendicularly and the irregularities of the cork are offset in the interfaces of each blade (5); g) Formation of parallelepipeds in microlayers which are cut into slices depending on the final product to be produced. Process for the manufacture of cylindrical bodies according to claim 1, characterized by the classification of the blades of step e) which can be carried out by visual selection or mechanical selection thanks to an electronic device (Scanner) (4). Process for the manufacture of cylindrical cork bodies according to claim 1, characterized by the formation of the parallelepiped in microlayers of step g) which is composed of a set of blades that vary according to the thickness of the blades used and the cylindrical body that we want to produce: - cap with a length of 45 mm and a diameter of 25 mm, the parallelepiped can be made up of an average of blades ranging from 416 to 12 (9); - washer with a length of 6.4 mm and a diameter of 30 mm, the parallelepiped can be made up of an average of blades ranging from 500 to 15 (10); Process for the manufacture of cylindrical cork bodies according to claims 1 to 3, since the microlayered cork slices can be tubed parallel (6) to the laminate sheets, perpendicular (7) or obliquely (8) with respect to the axis depending of the type of cylindrical body that one wishes to obtain. Cylindrical body of microlayered cork obtained by the method of claims 1 to 3, characterized by several cork blades with a thickness between 0.06 to 2 (2), positioned in a direction parallel (6) to the growth veins and in which the pores and irregularities of the cork on the different slats when glued and staggered at the interfaces, preventing them from communicating with each other, generate an almost total homogeneity (5) . Cylindrical body of cork with microlayers according to claim 6, characterized in that it comprises between 12 and 416 blades (9) when the cylindrical body has a length between 45 mm and a diameter of 25 mm. Cylindrical body of cork with microlayers according to Claim 5, characterized in that it comprises between 15 and 500 blades (10) when the cylindrical body has a length of 6.4 mm and a diameter of 30 mm. Cylindrical body of cork with microlayers in accordance with any of claims 4 to 6, characterized in that it forms a single piece of cork identical to a natural stopper and that it is homogeneous. Cylindrical body of cork with microlayers in accordance with any of claims 4 to 7, characterized in that it forms washers which will serve as components for technical corks.

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