METHOD FOR PRODUCE CYLINDRICAL BODY FROM LAMINATED CORK, AND FINAL PRODUCT OBTAINED BY THIS METHOD

Description

[0001] Introduction The invention relates to a method for manufacturing cylindrical cork bodies comprising the steps of: individual cleaning of each side of the sheet resulting from lamination; bonding with the application of a binder suitable for food contact and pressing so that the growth pores oriented perpendicular to the layers and the irregularities of the cork are offset at the interfaces of each layer; formation of parallelepipeds in microlayers which are cut into slices according to the final product. Such steps as well as the cylindrical body obtained are known from document FR 338 533 A

[0002] The beverage market, particularly the still and sparkling wine markets, predominantly uses cork closures, commonly known as cork stoppers. The use of cork meets the technical specifications required by the market, both in terms of its sealing capacity and the visual appeal that cork stoppers provide, which lends a true guarantee of quality to the beverage.

[0003] Since cork is a natural product, it presents difficult challenges to overcome during the manufacture of corks, namely: the visual uniformity of the cork; the uniformity in the physical behavior of the cork as a stopper; the absence of taste contaminants (e.g., trichloroanisol and other volatile substances)

[0004] The big challenge for the industry is to manufacture a cork stopper for markets that already use it, but clearly overcoming the 3 points mentioned above. State of the technique:

[0005] Cork is a natural product derived from the cork oak tree, composed of numerous microscopic hollow cells with harmonic cell walls that form a 100% natural tissue with unparalleled elasticity and resilience. These unique characteristics of cork are primarily used in the production of cork stoppers.

[0006] The traditional method of manufacturing cork stoppers presupposes the extraction of pieces of natural cork from cork oak trees. Because these pieces are extracted from a tree, they have an irregular concave shape ( Fig.1). In order for them to be used later in the manufacture of stoppers, the pieces of cork are subjected to a boiling and flattening treatment, which makes it possible to create flat and rectangular cork sheets, in strips, which are then cut into slices of appropriate thickness and drilled according to the invention using a tube-making machine, producing cylindrical cork bodies.

[0007] These cylindrical bodies then undergo the standard finishing processes, namely grinding, washing, surface treatment, and marking. This is the most traditional cork production method, with the least technological development in the sector, resulting in what is known as a natural cork.

[0008] This traditional method of producing cork stoppers is the most appreciated and widely used for the highest quality wines, as it naturally allows the use of the special characteristics of cork, the sealing and better preservation of the original flavors.

[0009] It turns out that the production of natural cork stoppers is insufficient to meet market demand. Furthermore, natural cork stoppers also have their drawbacks: they are highly heterogeneous due to their porosities, cracks, and hollows, which cause very visible and variable imperfections that can directly impact the mechanical behavior of the cork within the bottle, potentially leading to leaks and affecting the organoleptic neutrality required for stoppers in direct contact with the liquid inside the bottles. This type of undesirable reaction, which can affect the aroma of wines, is directly linked to a significant increase in the levels of 2,4,6-trichloroanisole (TCA). This type of contamination results from the interaction of certain fungi or parasites present in the cork, such as... Armillariamellea, and has a direct influence on the aroma of wines.

[0010] In order to meet market needs and address the drawbacks of natural cork, technical corks have emerged.

[0011] Technical cork stoppers are made up of several pieces of cork and may include cork parts or granules. The different types vary according to the arrangement and number of pieces, with or without a granular component.

[0012] Technical stoppers can be agglomerated stoppers; multi-piece stoppers with granules; and multi-piece stoppers that can result from two manufacturing processes: Continuous reactive extrusion; Closed-mold reaction compaction;

[0013] The technical cork, manufactured using a continuous reactive extrusion process, is based on the passage of cork granules, pre-moistened with a polymer, through a tubular section. Under the influence of temperature, this tube produces a cork granule rod. This rod is then cut into cylinders of the desired size, which, through the same finishing processes, become the final cork.

[0014] The technical cork manufactured using the compaction process (closed-mold reaction) is based on the injection of pre-moistened granulated cork mixed with a polymer. The injection is carried out in an individual mold which, under the influence of temperature, produces a cylindrical body of cork agglomerate. After standard finishing processes, this becomes the cork stopper. Individual compaction of the molds can be achieved by simultaneously adding washers, depending on the desired final cork (e.g., a 1+1 stopper, with two washers at the end).

[0015] Agglomerated corks are made from cork granules, obtained from waste products of natural cork production, and can be characterized by the different diameter sizes of the cork granules, which are then bonded with reactive adhesives. Corks with an average granule size between 2 mm and 8 mm are of lower quality than corks with an average granule size between 0.25 mm and 2.5 mm.

[0016] According to patents EP0496687 and EP2099689, we know of two processes for producing agglomerated corks.

[0017] In the first case, cork is composed of three components: a woody plant material which, for the manufacture of the stopper, is preferably a natural cork reduced to powder; a closed cellular plastic; a binder which, for the manufacture of stoppers, will preferably be a food-grade glue of the polyurethane or acrylic type.

[0018] In the second case, the cork is produced with two types of cork granules, which have complementary characteristics and for which the bond is established through an individual molding process.

[0019] The main drawback of this type of cork is that the liquid inside the bottle comes into contact not only with the cork granules but also with the binder, which can influence the aroma and quality of the liquid. Although these corks are inexpensive to produce, they are considered lower-quality and are therefore only used for lower-grade wines.

[0020] As a solution to these drawbacks mentioned for agglomerated stoppers, multi-piece technical stoppers made of granules have appeared.

[0021] Multi-piece granulated technical stoppers are composed of one or more pieces of cork, usually discs, and a granulated component or body, differing from each other according to the arrangement of the pieces in relation to the granule.

[0022] According to patents EP0481155 and EP0100302 we know of two processes for manufacturing multi-piece granulated stoppers, in which the process for manufacturing a cork stopper consists of a main body of granulated cork and at least one tip of natural cork with the pores arranged in a direction perpendicular to the axis of the stopper.

[0023] But these stoppers also have disadvantages, such as 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 means that the homogeneity of the stopper's behavior as a closure is not entirely satisfactory.

[0024] Still in the category of technical stoppers, we have multi-piece technical stoppers which are made up of 2 or more pieces of cork, without any granular component which differ in their organization in the constitution of the stopper.

[0025] According to patents EP1393869 and EP2093032, we know of two processes for manufacturing very similar multi-piece caps.

[0026] In the first case, the manufacturing process involves gluing several non-consecutive discs from the same cork panel with the interfaces between the discs substantially perpendicular to the veins of the cork and where the corks are drilled in the direction of the growth rings, resulting in a final cork composed of 3 cylindrical layers.

[0027] In the second case, the manufacturing process is very similar to the previous one, but in this case, the stopper is composed of two or more substantially cylindrical natural stopper elements connected by their bases after being selected, inspected and positioned according to the result of the inspection to form each stopper and where the veins of the stopper elements are in different angular positions relative to their longitudinal axes.

[0028] As with other types of technical stoppers, they also have their disadvantages, such as their external appearance because one can distinguish the overlapping transverse bands which correspond to the different layers that make up the stopper.

[0029] In the range of technical stoppers, we also have the international patent WO2011033485, the stopper resulting from this invention comes from the manufacturing process which consists of gluing together a set of 6 to 7 natural cork discs of 6 mm to 8 mm.

[0030] The present invention therefore consists of 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 existing caps on the market, as we shall see.

[0031] We can therefore conclude that for all corks known to date, their composition and manufacturing process present disadvantages, including for natural corks.

[0032] The major challenge in the cork market is producing a stopper that retains the advantages of natural cork, closely replicating its physical characteristics, guaranteeing greater organoleptic neutrality and physical homogeneity impossible to achieve with any other production method, even with natural cork, while also reducing production costs and avoiding the known drawbacks of technical stoppers. This is precisely the main objective of this invention. Description of the figures

[0033] Fig. 1- Show the piece of natural cork after boiling, resting and stacking, giving it a flat shape (1), we can see 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 strips (2) have been individually cleaned (3), sorted by levels of irregularity (4), rearranged and glued together with the irregularities of each strip offset and pressed, to create a parallelepiped with total physical homogeneity (5) visible over the whole piece; Fig. 4- Shows the parallelepiped resulting from the gluing of the 0.06 mm to 2 mm thick blades (2) and the shape of the cut of the cork strips for subsequent tubing, showing the physical homogeneity resulting from the gluing (5) along the piece; Fig. 5 - Shows the parallelepiped resulting from the bonding of the 0.06 mm to 2 mm thick blades (2) and the shape of the cut of the cork strips for subsequent tubing, showing the physical homogeneity resulting from the bonding. (5) along the whole piece and the cylindrical body resulting from the tubing 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 cut of the cork strips for subsequent tubing, showing the physical homogeneity resulting from the gluing (5) along the whole piece and the cylindrical body resulting from the tubing 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 blades (2) and the shape of the cut of the cork strips for subsequent tubing, showing the physical homogeneity resulting from the gluing (5) along the whole piece and the cylindrical body resulting from the tubing carried out parallel to the gluing of the blades (8); Detailed description of the invention

[0034] The present invention is a new method for manufacturing cylindrical cork bodies with microlayers characterized by a physical homogeneity unmatched compared to natural corks and technical corks known on the market and which is done by obtaining in the tree concave and elongated planks of natural cork and with the growth lines of the cork arranged perpendicular to the radial direction of the tree.

[0035] Natural cork boards undergo a boiling process in clean boiling water for 70 to 90 minutes at a temperature of 80 to 100°C, depending on the characteristics of the cork. This is followed by a flattening phase resulting from the boiling process, and the boards are then stacked to create a flattened piece. The cork is left to rest for 24 to 72 hours before the pulling phase begins.

[0036] For the present invention, the cork boards are baked at a temperature of 90 °C for 90 minutes.

[0037] The cork cooking process is important because it makes the cork more uniform and increases its volume. It is also an effective mechanism for reducing microflora and consequently improving the internal structure of the cork.

[0038] The cooking process used in the present invention is that traditionally used for cooking natural cork boards.

[0039] The cutting of the already flat cork sheets is carried out using a machine for slicing cork sheets composed of: of a circular plate on which the cork boards are fixed to knurled plates; of a rotating knife.

[0040] During the lamination process, the circular plate with the cork boards attached passes successively through the rotating knife which cuts the cork boards into thicknesses ranging from 0.06 mm to 2 mm (2).

[0041] The lamination process of the present invention and the mechanical equipment used do not in themselves constitute a technical feature of the present invention, since they are known processes for laminating cork sheets. The technical feature lies in the reduced thickness of the sheets obtained by the lamination process, from 0.06 mm to 2 mm (2), and their use in the composition of cork parallelepipeds for lining microlayer cylinders used as beverage stoppers.

[0042] Next comes the cleaning of each individual blade (3). The reduced thickness of the cork blades, ranging from 0.06 mm to 2 mm (2), which differs from all other known production processes, allows for better cleaning, as it is carried out individually on each side of the blades, resulting in almost total organoleptic neutrality. The cleaning process consists of deodorizing and disinfecting contaminants. Considering the reduced thickness of the blades, between 0.06 mm and 2 mm (2), which will make up the parallelepiped, it is easy to understand that the volumetric cleaning surface area is much greater than that of the discs, whose thickness is far greater than the maximum thickness of 2 mm that the blades of the invention can achieve.

[0043] The cleaning process used for the present invention does not in itself represent a technical feature of the invention, since 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 multi-piece corks.

[0044] The cork strips produced are classified by quality of material, either by visual selection or by mechanical selection using an electronic device (Scanner) (4), according to the levels of irregularities.

[0045] In this way, it is possible to create a uniform quality of cork when constructing the parallelepiped compared to a natural cork board.

[0046] Once the strips are obtained, they are bonded using a food-grade adhesive. We always use the adhesive that is currently available on the market and offers the best qualities. The individual strips are bonded according to the classification obtained (4), ensuring that the pores resulting from the growth lines and the natural irregularities of the cork are staggered at the interfaces of each strip, preventing them from communicating with one another. This bonding method, in which the cork's irregularities are staggered to create a physically homogeneous parallelepiped (5), represents a true innovation.

[0047] In this way, we obtain a physical homogeneity impossible to achieve with the methods already known from all other patents and natural corks, where one of the disadvantages noted is precisely the impossibility of eliminating the irregularities of the cork.

[0048] Once bonded, the blades are pressed. This pressing can be done with light or heavy pressure and can be performed hot or cold. The pressing pressure will directly impact the final elasticity of the product; therefore, the present invention employs a light pressing process that will guarantee higher available elasticity and consequently better sealing levels for the cylindrical bodies produced by this new process.

[0049] The gluing and pressing process used does not in itself represent a technical feature of the invention, because we will always use at the time of application the binder and press which are used on the market at that time and which combine the best qualities, the particularity lies in the fact that at the time of gluing the reduced thickness strips of 0.06 mm to 2 mm (2), we manage to effectively eliminate the irregularities of the cork by gluing each strip by offsetting the irregularities of the cork of each strip (5), thus guaranteeing a greater and better density compared to existing corks on the market, whether natural or technical.

[0050] 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 production, achieves unprecedented results compared to existing corks, because it is not necessary to use large quantities of glue.

[0051] Cork for natural stoppers (of good quality) has a weight or specific density of natural stopper between 170 and 190 kg / m3 => 180 kg / m3 + / - 10 kg / m3.

[0052] For micro-granulated technical plugs, the weight or specific density is between 280 and 300 kg / m3 => 290 kg / m3 + / - 10 Kg / m3.

[0053] 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.

[0054] As we can see, the cylindrical bodies resulting from the present invention are close to the values ​​of natural plugs, and they should even exceed them.

[0055] From the strips obtained through the gluing process, a parallelepiped is produced that can be cut to dimensions that allow for optimal tubing (6, 7, and 8) for the desired final product, the production of micro-layered corks, or the production of discs for technical corks. This optimization is defined according to the dimensions of the cork cylinder to be produced, and the tubing direction can be modified depending on the desired product. The cork parallelepipeds can replicate the strips used for traditional perforation in tubing machines commonly used in the manufacture of natural corks or in traditional tubing machines for the production of discs.

[0056] Other tubing techniques can also be developed to optimize industrial yield in the production of caps or washers.

[0057] The parallelepipeds resulting from the gluing of cork strips with a thickness between 0.06 mm and 2 mm (2) are composed of an average number of strips that varies depending on the type of cylindrical body to be produced. In a cork used for sealing with a length of 45 mm and a diameter of 25 mm (the standard size for corks used to seal fortified wines), the parallelepiped may be composed of an average of 416 to 12 strips (9). In a disc used for the manufacture of technical corks (standard-sized discs used for sparkling wine corks) with a length of 6.4 mm and a diameter of 30 mm, the parallelepiped may be composed of an average of 500 to 15 strips (10).

[0058] The cylindrical bodies resulting from the new process consist of several cork strips which are positioned relative to the axis of the cylinder according to the direction of the tubing and which can be carried out parallel to the direction of the laminated sheets (6), perpendicularly (7) or obliquely (8) relative to the axis of the part, depending on the type and cylindrical body that one wants to obtain.

[0059] Since it is possible to tube in any direction, it is possible to obtain greater profitability from the entire piece of cork.

[0060] For the production of corks intended for still wines, the preferred tubing process is that done in the direction parallel to that of the laminated sheets (6), thus obtaining a visual effect similar to that of natural cork.

[0061] Once tubed, the corks are subjected to the usual finalization, sanding and finishing processes, without resorting to cosmetic impressions, which are widely used in technical corks to approximate the visual image of natural corks.

[0062] For the production of washers which will serve as components for technical stoppers, it is preferable that the cork strips be positioned perpendicular to the axis of the cylinder, i.e. along its length (7), thus producing a visual effect similar to washers made from a piece of cork (natural washer). Characteristics of cylindrical bodies (plugs or washers) obtained by the process of the present invention (the end result of the process is the manufacture of microlayered cork cylinders):

[0063] All the following characteristics of the cylindrical bodies result from the fact that, in the process of the present invention, the cork strips used have such a small thickness, between 0.06 mm and 2 mm (2), allowing a larger quantity of cork to be cleaned, cleaning carried out individually, strip by strip (3) taking into account the large quantity of cork strips used for the manufacture of cylindrical bodies (9 and 10), as well as the almost complete elimination of the irregularities and pores characteristic of natural cork at the time of the selection of the strips (4) and the gluing of the strips (5).

[0064] 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 (stoppers or washers) to a natural cork, due to the high volume of cork used in its composition, resulting from the bonding of thin cork sheets; Total physical homogeneity in terms of density compared to corks produced on the current market, according to a previously published comparative market study; Total physical homogeneity along the cylindrical body in terms of density, porosity, and elasticity compared to a 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;Organoleptic neutrality thanks to the cleaning of a larger cork surface area (deodorization and disinfection) because the treatments are administered layer by layer, guaranteeing a large surface cleaning volume; Stoppers made from cork of all classes and sizes, without restrictions similar to those of other cork stoppers; The possibility of manufacturing corks of all sizes, including other components (e.g., cork washers) with total homogeneity, whereas in the traditional manufacture of natural or technical corks, the final product is very heterogeneous; Optimized tubing because it can be tubed longitudinally, perpendicularly, or obliquely to the axis of the part, depending on the type and cylindrical body desired; Low production cost.

Claims

1. A method for manufacturing cylindrical cork bodies comprising the following steps: a) Cooking the natural cork board for 70 to 90 minutes at a temperature between 80°C and 100°C, and a flattening (1) due to the cooking step (1); b) Allowing the cork to rest for a period of 24h to 72 h; c) Laminating the cork board using a cork slicing machine into cork sheets of small thickness comprised between 0.06 and 2 mm (2); d) Individually cleaning each side of the sheet resulting from the laminating step (3); e) Classifying the sheets according to the quality of the material (4); f) Bonding the sheets by applying a binder suitable for food and pressing them such that the growth pores oriented perpendicularly to the sheets and the cork irregularities are offset at the interfaces between each sheet (5); g) Forming parallelepipeds made of microlayers, which are cut into slices depending on the intended final product, and tubing the parallelepipeds according to the desired final product.

2. The method for manufacturing cylindrical bodies according to claim 1, wherein the classification of the sheets in step e) is carried out by visual selection or by mechanical selection using an electronic device such as a scanner (4).

3. The method for manufacturing cylindrical cork bodies according to claim 1, wherein the microlayer parallelepiped formed in step g) is composed of a set of sheets, the number of which varies depending on the thickness of the sheets used and on the cylindrical body to be produced: - for a stopper having a length of 45 mm and a diameter of 25 mm, the parallelepiped may be formed from an average number of sheets ranging from 12 to 416 (9); - for a washer having a length of 6.4 mm and a diameter of 30 mm, the parallelepiped may be formed from an average number of sheets ranging from 15 to 500 (10);4. The method for manufacturing cylindrical cork bodies according to claims 1 to 3, wherein the microlayer cork slices may be tubed parallel (6) to the laminated sheets, perpendicular (7) thereto, or obliquely (8) relative to the axis, depending on the type of cylindrical body to be obtained.

5. A microlayer cylindrical cork body obtained by the method according to claims 1 to 3, wherein a plurality of cork sheets having a thickness between 0.06 and 2 mm (2) are positioned in a direction parallel (6) to the growth veins, and wherein the pores and irregularities of the cork on the different sheets, once bonded, are offset at the interfaces, preventing communication therebetween and generating an almost total homogeneity (5).

6. The microlayer cylindrical cork body according to claim 5, which comprises between 12 and 416 sheets (9) when the cylindrical body has a length of about 45 mm and a diameter of about 25 mm.

7. The microlayer cylindrical cork body according to claim 5, which comprises between 15 and 500 sheets (10) when the cylindrical body has a length of 6.4 mm and a diameter of 30 mm.

8. The microlayer cylindrical cork body according to any one of claims 5 to 7, forming a single homogeneous cork piece identical to a natural cork stopper.

9. The microlayer cylindrical cork body according to any one of claims 5 to 8, forming washers intended to serve as components for technical stoppers.