Method for manufacturing a leak-proof, pasteurizable and sterilizable closure system for bottles with separate lids, and closure system obtainable by the method
Patent Information
- Authority / Receiving Office
- ES · ES
- Patent Type
- Patents
- Filing Date
- 2024-02-29
- Publication Date
- 2026-07-13
AI Technical Summary
Existing glass jar closure systems require manual application of a sealing gasket and lid, are difficult to automate, and result in high labor costs, with the lid being fragile and not resealable after initial opening.
A multilayer plastic lid with a built-in sealing gasket, comprising polypropylene layers framing an ethylene vinyl alcohol barrier, featuring a circular groove for the gasket and snap-on means, allowing automated assembly and resealability.
Enables automated, cost-effective, and airtight closure systems that reduce labor costs, enhance durability, and allow resealing after initial opening, suitable for pasteurization and sterilization.
Smart Images
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Abstract
Description
[0001] The present invention relates to the general field of containers used in the food industry and, more particularly, to glass containers, such as jars, intended to be hermetically sealed with a lid, before pasteurization - sterilization (appertization), vacuum sealing and preservation.
[0002] The present invention relates, more particularly, to a method of manufacturing a closure system, of the lid type, in a multilayer material consisting, at least, of an EVOH (ethylene vinyl alcohol) layer sandwiched between two layers of thick polypropylene, said method further including the integration, preferably in an automated manner, of a sealing gasket at the level of the internal surface of the lid, intended to come into contact with a container to be closed.
[0003] Traditionally, in the state of the art, in order to preserve various foods, it has been known for many years to place them in containers, in particular jars, generally made of glass, before hermetically sealing these with a lid and then sterilizing them at a temperature above 100°C, or pasteurizing them at a temperature less than or equal to 100°C.
[0004] This step can be carried out using an autoclave sterilizer, and significantly reduces the microbial load present in the product and / or the basic food preparation, thus preventing microbial growth and ensuring food preservation for varying lengths of time depending on the heat treatment applied. This step requires prior vacuum sealing of the container using this type of closure device.
[0005] That being said, the closing of glass jars, with separate lid and sealing gasket, currently encounters a problem, in particular in the application of the gasket and in the placement of the lid, with said gasket, on the upper part, or ring, of the jar.
[0006] Indeed, fitting the seal to the underside of a glass lid is a task that can only be done manually and individually for each jar to be prepared, therefore requiring a large number of staff.
[0007] The same applies to fitting the lid with the seal onto the jar.
[0008] In addition, the lid, fitted with the seal, must be held, for example by means of at least two clips, or by a metal loop, on the jar, during the sterilization (appertization) or pasteurization phase, the clips being able to be removed after cooling.
[0009] However, the application of the seal to the underside of the lid, as well as the application of the lid and seal to the container, are operations that are difficult to automate, which generates a significant labor cost for the user, and hinders the development of food product ranges in such containers in industrial or semi-industrial settings.
[0010] As a result, the implementation of this type of glass jar is neglected by manufacturers, but also by craftsmen, the process of placing the seal on the lid, and the whole thus formed on the jar, being time-consuming and complicated.
[0011] It should also be noted that the use of glass for the lid makes it fragile during handling.
[0012] Also, the lid is, in some cases, as heavy as, or even heavier than, the jar itself, especially when the latter consists of a small model of jar.
[0013] Another disadvantage of this type of jar once sterilized is that, after the first opening, a jar closed with a removable and separate lid, with a seal, cannot be resealed in a semi-airtight manner for delayed consumption, once the jar has been opened.
[0014] Also known in the prior art is US patent 9884716, which describes packaging with a container and a lid adapted to fit onto the rim of the container to close its opening. US patent 9884716 essentially describes a method for manufacturing a leak-proof and sterilizable closure system, comprising a lid designed to hermetically seal a container, and including a foil support ring and a membrane sheet configured to be coupled to the edge of an upper ring on the container to establish a fluid seal between said sheet and said edge when the lid is mounted on the container. This method includes the following steps: - thermoforming or molding the foil support ring from suitable plastic materials such as polypropylene (PP) or high-density polyethylene (HDPE),polyethylene terephthalate (PET) or crystalline polyethylene terephthalate (CPET), optionally co-extruded with barrier polymers such as ethylene vinyl alcohol (EVOH) or polyvinylidene chloride (PVDC) in a core layer; - manufacture of the membrane sheet from a co-extruded film or sheet comprising, for example, PP or HDPE and possibly including one or more barrier layers such as EVOH, nylon or PVDC, bonding layers and a sealing layer, said sheet being flexible and configured to deform and adapt in response to pressure changes in the container, and being peelable to facilitate detachment from the container rim when removing the container lid; - overmolding of said sheet support ring onto the membrane sheet to form the lid or permanently bonding of the membrane sheet to the sheet support ring,The said leaf support ring is further configured to temporarily couple in a clip-like fashion with a portion of the container's edge so that the lid is removable and resealable. US patent 9884716 also describes a corresponding closure system.
[0015] In this packaging, the lid and parts of the container are expandable and capable of expanding without bursting when the pressure inside the container increases during exposure of said packaging to high temperatures, to take on inflated shapes.
[0016] During cooling after exiting the oven, as the pressure inside the packaging decreases, the expandable elastic parts of the packaging deflate and contract to return to their original shape.
[0017] In this document, the presence of a sealing gasket is not required, so the packaging may not be completely airtight.
[0018] It should also be noted that, in this packaging, the lid is formed in two parts, namely a sheet support ring, made of a robust material and configured to couple with the upper edge of the packaging container, and a membrane sheet made of expandable elastic material, permanently coupled with the sheet support ring.
[0019] The two-part design of this lid makes it more difficult to assemble and secure on the container. Furthermore, once the container has been opened by removing the membrane and its support ring, it is very difficult to reclose, and in any case, not in a way that ensures a sufficient seal for delayed consumption of the food inside.
[0020] The present invention aims to remedy, at least in part, the disadvantages of prior art packaging, in particular the exclusively manual processes of applying a seal to a lid and of applying the lid and seal assembly to the ring of the jar implemented in the prior art, by proposing a method of manufacturing a leak-proof, pasteurizable and sterilizable closure system for jars with separate lids made of a multi-layered plastic material.
[0021] To this end, the invention relates, more particularly, to a method for manufacturing a hermetic, pasteurizable and sterilizable closure system comprising a lid and a sealing gasket, intended to hermetically seal a container, in particular a glass jar, said sealing gasket being positioned at the edge of an upper ring comprising said container, said method being characterized in that it comprises, at least, the following steps, taken in order: formation, by extrusion, of a multilayer master roll comprising at least two layers of polypropylene (PP) resistant to a temperature between 100°C and 150°C, which frame a central barrier layer of ethylene vinyl alcohol (EVOH), said multilayer master roll being suitable for food contact;thermoforming and cutting, from said multilayer master roll, of the lid, by means of forming molds, so that said lid obtained has, at least, at the level of its lower face, a circular groove constituting a housing for the sealing gasket intended to come into contact with the edge of the upper ring of the container, a central portion of said lid forming a convex dome raised outwards before vacuuming and capable of retracting to become concave during vacuuming, while a circular groove surrounding the convex dome is provided at the level of the upper face of the lid, the latter being further provided on its entire perimeter with a closing rim comprising a plurality of snap-on means capable of cooperating with said upper ring of said container;placement of said sealing gasket in the circular groove on the underside of the lid to obtain said airtight, pasteurizable and sterilizable closure system; optionally, cooling of said airtight, pasteurizable and sterilizable closure system.
[0022] Examples of how the process is implemented: The said sealing gasket is a preformed gasket. The said sealing gasket is deposited in liquid or paste form in the said circular groove, prior to a polymerization phase.
[0023] In one embodiment of the process of the invention, in the first step thereof, a multilayer master roll of PP-EVOH-PP-flexible polymer is formed by extrusion, the flexible polymer layer constituting the sealing joint in the circular groove.
[0024] According to examples of how the process is implemented, both when the sealing gasket is placed in the circular groove and when it is directly integrated into the multi-layered master roll: The polypropylene layer contains color pigments. The EVOH barrier layer has a thickness ranging from 10 µm to 10% of the total thickness of the multilayer master roll. The thermoformed lid also includes an opening tab. The thermoformed lid also includes a conical finishing edge forming a flare at the top face of the lid.
[0025] The invention also relates to a leak-proof, pasteurizable and sterilizable closure system that can be obtained using the manufacturing process according to the invention.
[0026] This device comprises a lid and a sealing gasket, intended to hermetically seal a container, in particular a glass jar, said sealing gasket being positioned at the edge of an upper ring of said container, said closure system being characterized in that said lid is made of multilayer plastic material suitable for food contact and comprising at least two layers of polypropylene (PP) resistant to a temperature between 100°C and 150°C and framing a barrier layer of ethylene vinyl alcohol (EVOH), said lid comprising at least, on its underside, a circular groove constituting the housing in which the sealing gasket is placed, a central portion of said lid forming a convex dome raised outwards before vacuuming and capable of contracting to become concave during vacuuming, while a circular groove surrounding the convex dome,is provided at the level of the upper face of the lid, the latter also being provided, around its entire perimeter, with a closing rim in the form of a skirt comprising a plurality of latching means capable of cooperating with said upper ring of said container.
[0027] Preferably, the locking system has the following additional characteristics: It is provided with a conical finishing rim forming on the upper face of the lid, at the base of the thermoformed lid, for interaction with the outer surface of the circular groove of a second locking system during stacking. The lid has a lateral opening tab; the lid locking means adapted to cooperate with the upper ring of the container consist of a clip groove extending along almost the entire perimeter of the closing rim in the form of a skirt, except for a plurality of regularly distributed portions on said perimeter where a stiffener is provided; the lid locking means consist of a plurality of internal locking notches, regularly distributed around the entire perimeter of said skirt. The sealing gasket is a preformed gasket made of a thermoplastic elastomer, TPS-SEBS.
[0028] Other objects and advantages of the present invention will become apparent during the following description relating to embodiments which are given only as indicative and non-limiting examples.
[0029] Understanding this description will be facilitated by referring to the attached drawings, in which: [ Fig.1 ] represents a schematic top view (left) and section BB view (right) of an embodiment of a hermetic, pasteurizable and sterilizable closure system, obtainable by means of the manufacturing process according to the present invention, intended to hermetically seal a container, such as a glass jar, comprising a lid and a sealing gasket inserted in a circular groove in the underside of said lid, said gasket being intended to come into contact with the edge of an upper ring in the glass jar to seal it hermetically after vacuum sealing. Fig.2 ] represents a top-view photograph of a hermetic, pasteurizable and sterilizable closure system obtainable according to the manufacturing process of the invention, comprising, laterally, an opening tab, and the central portion of the lid having the shape of a convex dome raised outwards, relative to the container, before the latter is vacuum-sealed. Fig.3 ] represents a top-down photograph of the airtight, pasteurizable, and sterilizable closure system similar to that of the figure 2 After the container was vacuum-sealed, the central portion of the lid, which was a convex dome raised outwards before vacuuming, contracted inwards to become concave during the vacuuming process. Fig.4 [ ] represents a photograph of the underside of the lid, with the seal positioned in the circular groove to form the closure system of the invention. Fig.5 [ ] represents a schematic and enlarged view, in diametrical section, of a portion of the lid, illustrating a particular embodiment thereof, notably featuring a plurality of inward-facing, or internal, bosses relative to the circular groove into which the sealing gasket is inserted, also shown in this figure. These inward-facing bosses are positioned alternately with outward-facing, or external, bosses to facilitate stacking the lids one on top of the other. Fig.6 ] represents another schematic view in partial cross-section, of the embodiment illustrated on the figure 5 , and on which is also visible the central portion of the lid in the form of a convex dome raised outwards, relative to the container, before the latter was vacuum-sealed.
[0030] With reference to the figures in the attached drawings, the present invention relates, more particularly, to a method for manufacturing a leak-proof, pasteurizable and sterilizable closure system 1.
[0031] This system 1 is intended to close the edge of a container 4, such as a jar, made of glass or plastic, before vacuum sealing, pasteurization or sterilization of the whole consisting of said container 4 associated with its closure system 1, said container 4 having been previously partially filled with a food product that one wishes to preserve.
[0032] Such a leak-proof, pasteurizable and sterilizable closure system 1 essentially comprises a lid 2, and a sealing gasket 3 positioned at the lower face 21 of said lid 2, in other words the face 21 intended to come into contact with the edge of the container 4.
[0033] More specifically, at the time of positioning the closure system 1 on the container 4 to close it, said sealing gasket 3 comes into contact with the edge of a top ring, or top rim, not visible in the figures, to allow a hermetic closure of the container 4 by vacuuming before pasteurization or sterilization of the assembly.
[0034] In a first step of the manufacturing process of a closure system 1 according to the invention, a multilayer master roll is formed by extrusion.
[0035] This master roll thus comprises, at least, two layers of polypropylene (PP) sandwiching a "barrier layer" made of ethylene vinyl alcohol (EVOH).
[0036] The PP used for the two outer layers of the multilayer master roll consists of a so-called "high temperature" PP, meaning that it is capable of withstanding temperatures of at least 125°C during heat treatment, and up to a maximum of 150°C in the short term, depending on the technical constraints.
[0037] The EVOH barrier layer framed by the aforementioned two external layers of high-temperature PP has a thickness between 10µm and 10% of the total thickness of the PP-EVOH-PP film.
[0038] The multi-layer roll is formed by extrusion and during this process, the two materials PP and EVOH will overlap and bond together during cooling.
[0039] PP thicknesses can vary depending on the technical constraints of container 4, in particular depending on the diameter of the latter.
[0040] Note that it is essential that the multilayer material, made of PP and EVOH, be suitable for food contact, as is the material in which the sealing gasket 3 is made, the latter being in particular silicone, rubber, or any other material suitable for this purpose.
[0041] Even more preferably, the sealing gasket is an injected gasket and consists of a thermoplastic elastomer, TPS-SEBS, in other words, styrene thermoplastic (TPS) based on styrene-ethylene-butylene-styrene (SEBS).
[0042] In an advantageous embodiment of the process of the invention, the polypropylene layer extruded during the first step of the process, for the formation of the multilayer roll, may include color pigments.
[0043] Indeed, advantageously, by means of the manufacturing process for closure systems 1 of the invention, the latter can be customized, the cover 2 thus being able to display different colors or logos.
[0044] Most preferably, the central EVOH barrier layer of the multilayer roll obtained following the first step of the manufacturing process of the invention has a thickness between 10µm and 10% of the total thickness of the film, this thickness of the EVOH barrier layer being, even more preferably, on the order of, or equal to, 80 µm.
[0045] The thickness of the EVOH barrier layer can, however, vary depending on the technical constraints of the container.
[0046] A second step in the manufacturing process of the invention consists of thermoforming the element and cutting it, using a forming mold, to obtain the lid 2 at the end of the process.
[0047] Note that this thermoforming operation is carried out using the mold in such a way that the said lid 2 finally obtained has, at least, at the level of its lower face 21, a circular groove 5 constituting a housing for the said sealing gasket 3 which is intended to come into contact with the edge of the upper ring of the container 4 at the time of the closure of the latter by the system 1.
[0048] In addition, a central circular portion 23 of said lid 2 forms, after thermoforming, a convex dome 23a raised outwards, relative to the container 4 once the closure system 1 is positioned on the open part of the latter, before vacuuming the assembly consisting of the container 4 and the closure system 1 of the latter.
[0049] The said central circular portion 23 in the form of a convex dome 23a is also capable of contracting to become concave 23b when the container 4 is placed under vacuum, in particular by heat treatment of the whole.
[0050] A circular groove 24 surrounding the convex dome 23a, at the level of the upper face 22 of the lid 2, allows the deformation of the latter under the action of the vacuum to be limited to the portion of this dome 23a only.
[0051] This prevents the formation of folds in the peripheral area of the cover 2, particularly in the area of cooperation of said cover 2 with the sealing gasket 3.
[0052] Indeed, the presence of folds in the circular groove 5 which forms the housing for the sealing gasket 3 would allow air to circulate between the inside and outside of the closed container and, consequently, a loss of vacuum.
[0053] It should also be noted that the thermoforming operation must allow obtaining a lid 2 whose closing rim 6, in the form of a skirt intended to cover and cooperate with the upper ring of the container 4, includes means for snapping said lid 2 onto said upper ring of said container, for example in the form of a plurality of internal closing notches 61, distributed regularly around the entire perimeter of said skirt.
[0054] Based on the example of implementation illustrated on the figure 1 In the attached drawings, six closing notches 61 are shown. However, this embodiment should not be considered limiting, and a different number of closing notches 61 may be envisaged; in particular, ten closing notches may be evenly distributed around the entire perimeter of the closing rim 6.
[0055] Such internal closure notches 61 allow, once the closure system 1 has been removed from the container 4 for the first consumption of part of the food product inside it, to reposition said closure system 1 in a partially airtight manner, by clipping.
[0056] Indeed, the seal after first opening, made possible by the presence of the notches 61 when closing the jar 4, was estimated at approximately 90%, compared to a total seal after vacuum sealing, constituting a particularly interesting seal for this type of product.
[0057] In another example of a particularly preferential implementation, illustrated on the figure 5 et 6 In the attached drawings, the said means for snapping said cover 2 onto the upper ring of a container 4 are in the form of a clip groove 62 running almost the entire perimeter of the closing rim 6 in the form of a skirt, with the exception of portions of the perimeter at which stiffeners 63 are provided.
[0058] Thus, the action of the ratcheting means is maximized so as to increase the retention and holding of the lid 2, in particular during vacuum sealing.
[0059] The presence of the stiffeners 63 distributed regularly around the perimeter of the skirt allows a shaping of the clip groove 62 so that, under the effect of pressure and temperature, it retains its geometry.
[0060] Preferably, and as illustrated on the figures 2 , 3 et 4 , the thermoforming step allows obtaining a lateral opening tab 7 at the level of the lid 2, facilitating the first opening and the airing of the container 4 to allow consumption of the food product inside.
[0061] Following the thermoforming step and obtaining the lid 2, the next step of the manufacturing process according to the invention consists of placing the sealing gasket 3 in the circular groove 5 provided at the level of the lower face 21 of the lid 2.
[0062] Two types of seals 3 can be placed in the circular groove 5.
[0063] In a first, particularly preferential example, a pre-formed and ready-to-use sealing gasket 3 can be placed either mechanically or manually in said groove 5.
[0064] The sealing gasket 3 can be obtained here by injecting a flexible material (in particular silicone) or cut from sheets / plates of silicone or rubber (in particular natural).
[0065] In this case, the sealing gasket 3 is secured to the cover 2 by means of a plurality of micro-hooks, in the form of undercuts in the circular groove 5.
[0066] In such an example of embodiment, most preferably, and as already mentioned, the injection-molded seal which is inserted into groove 5 is made of a thermoplastic elastomer material, TPS-SEBS.
[0067] Now, referring to the figure 5 annexed, when the injected sealing gasket is inserted into the groove 5, and in particular when it is a TPS-SEBS gasket, said groove 5 is provided with a plurality of bosses 51, or internal, inwards relative to the circular groove 5 in which the sealing gasket 3 is inserted.
[0068] The recessed bosses 51 allow the sealing gasket 3 to be wedged in its housing, namely the groove 5, in order to allow the pre-assembled lid 2 to be handled, with said injected gasket 3 positioned in the groove 5 of the lid 2, ready to be used to close a container 4.
[0069] The said inward bosses 51 can be positioned alternately with outward bosses 52, or external bosses, the latter having the effect of facilitating the stacking of the covers one on top of the other.
[0070] The external bosses 52, for their part, have the effect of allowing the lids 2 to stack correctly on top of each other, in terms of support and centering, so as to be able to be packaged in stacks, to be able to be used in automatic destacking machines to allow automatic placement of the seal 3 in the groove 5 of the lid 2 or of the lid 2 fitted with its seal 3 on a jar 4, in particular made of glass.
[0071] Preferably, but not exclusively, the perimeter of the groove 5 intended to contain said sealing joint 3 is provided, distributed alternately and regularly, with eight inward bosses 51 and eight outward bosses 52.
[0072] It should also be noted that, advantageously, still with reference to the figure 5 , the inner face 53 of the housing of the seal 3 in the lid 2, namely the inner face of the groove 5, is vertical, with the exception of the plurality of recessed bosses 51 so as to hold said seal 3 in place when the closed jar 4 is vacuum-sealed, in particular glass.
[0073] In another embodiment, it may be a sealing gasket 3 deposited in liquid or paste form in said groove 5, which will require a conformation so that the face of the gasket 5 which must cooperate with the edge of the container 4 is geometrically suitable for this cooperation, then a polymerization phase, which will depend on the polymer, the latter being able in particular to consist of silicone.
[0074] Polymerization allows the change of state of the sealing joint 3.
[0075] Indeed, during this step, said joint 3 passes from a viscous phase to an elastic phase.
[0076] Depending on the material of the seal, such polymerization is carried out either by temperature, by chemical reaction between two components, or by cross-linking, in the case of rubber.
[0077] In one embodiment of the manufacturing process of the invention, a multilayer PP-EVOH-PP-flexible polymer film is extruded. Thermoforming and then cutting produce a part that already provides the sealing function, with the flexible polymer layer constituting the sealing gasket.
[0078] This gives us said airtight, pasteurizable and sterilizable closure system 1 consisting of the lid 2 and said sealing gasket 3.
[0079] Particularly advantageously, thanks to the manufacturing process of a closure system 1 for a container 4 intended for preserving food, the step of depositing the sealing gasket 3 at the lower face 21 of the lid 2 can be carried out in a fully automated manner.
[0080] This eliminates the need to use labor specifically for this step, unlike what is currently done in the state of the art, to obtain glass jars containing food ready to be preserved under vacuum or heat-treated.
[0081] During the final stage of the manufacturing process of the leak-proof, pasteurizable and sterilizable closure system 1 of the invention, in particular following polymerization, the said system 1 is cooled.
[0082] The 1-jar closure systems 4 thus manufactured can, therefore, advantageously be stacked in a subsequent and optional stage, for use with automated destackers, to automatically reseal 4-containers filled with food products.
[0083] Thus, the process of the invention is particularly interesting for the development of the industrialization of food products contained in jars 4, in particular glass, sealed airtight before being vacuum-sealed, for optimal preservation of said products under aseptic conditions.
[0084] Indeed, on the one hand, the process of the invention eliminates the currently existing step of manually placing the seal on the underside of the lid, as well as the placement and removal of the clips to hold the seal and lid assembly onto the jar.
[0085] The manufacture of the closure system 1 by the process of the invention allows for complete automation of the closure cycle of the containers 4, using existing machines, which may need to be modified.
[0086] The closure systems thus obtained can also be used with conventional bell-type vacuum machines, while manual placement of the lid also remains feasible for vacuum sealing.
[0087] Leak-proof, pasteurizable and sterilizable closure systems 1 can be manufactured in such a way as to be able to be adapted to different types of jars 4, including different sizes, without modification of the latter.
[0088] The lids 2 can also be easily customized by adding the manufacturer's logo and / or by customizing the color of the polypropylene main sheath.
[0089] After a first opening, a container 4 can be resealed by the closure system 1 obtained by implementing the process of the invention, with a satisfactory seal for such a re-closing operation and short-term storage.
[0090] The manufacture of such closure systems 1, based on plastic materials, which are also recyclable, allows a reduction in the weight of the entire jar and lid, compared with existing assemblies made entirely of glass.
[0091] Thus, the process of the invention allows the obtaining of closure systems 1 allowing optimal and aesthetic sealing of the edge of a container 4.
[0092] Note that such systems 1 can be used both for simple vacuum sealing of jars without heat treatment, with the advantages of vacuum sealing, and for pasteurization, with medium-term preservation while respecting the cold chain, or even for sterilization of jars 4 with long-term storage at room temperature.
[0093] The present invention also relates to a leak-proof, pasteurizable and sterilizable closure system 1 that can be obtained by implementing the manufacturing process as described above.
[0094] According to the invention, such a closure system 1 comprises, on the one hand, a lid 2 and, on the other hand, a sealing gasket 3, intended to hermetically close a container 4, such as a glass or plastic jar, said sealing gasket 3 being intimately associated with the lid 2.
[0095] According to one feature of the present invention, said lid 2 is made of a multilayer plastic material, suitable for food contact, and comprising at least two layers of high-temperature PP framing an EVOH barrier layer of variable thickness depending on the technical constraints.
[0096] The said cover 2 has at least, at the level of its lower face 21, intended to come into contact with the edge of the container 4, a circular groove 5 constituting the housing in which the sealing gasket 3 is placed.
[0097] Essentially, a central circular portion 23 of said lid 2 forms a convex dome 23a, raised outwards, relative to the container 4, before vacuuming and capable of retracting to become concave 23b, inwards towards said container 4, once vacuuming has been carried out.
[0098] Such a feature, namely the passage of the central circular portion 23 of the lid 2 from a convex shape to a concave shape allows visual control of the vacuuming of the container 4, as well as monitoring of the maintenance of the vacuum, by analysis of the deformation.
[0099] A circular groove 24 which surrounds this central circular portion 23, capable of passing from a convex shape 23a to a concave shape 23b, is provided at the level of the upper face 22 of the lid 2.
[0100] The lid 2 of the closure system 1 is also provided, around its entire perimeter, with a closure rim 6, in the form of a skirt intended to cover the upper ring of the container, and comprising a plurality of closure notches 61 capable of cooperating with this ring for optimal sealing of the latter after the first opening.
[0101] Preferably, and as can be seen in particular on the figure 1, the thermoformed lid 2 also has, at its external face 22, a conical finishing rim 8 at the base of the thermoformed lid 2, this conical rim 8 forming a flare, so as to allow the cooperation of a first closure system 1 with the external surface of the circular groove 5 of a second similar closure system 1, to guarantee a stable stacking of these closure systems 1, before their placement on the edge of the container 4.
[0102] With this feature, it is possible to work on the placement of closure systems 1 in an automated, stacked manner, for future loaders or destackers.
[0103] Note that the characteristics described in this application in connection with the manufacturing process of closure systems 1 are applicable to closure systems 1, which may be obtained by means of this process, or by another process, and vice versa.
Claims
1. A method for manufacturing a sealed, pasteurisable and sterilisable closure system (1), comprising a lid (2) and a seal (3), intended to hermetically close a container (4), in particular a glass jar, said seal (3) being positioned at the edge of an upper ring that said container (4) comprises, said method being characterised in that it comprises, at least, the following steps, considered in sequence: - forming, by extrusion, a multilayer stock roll comprising at least two layers of polypropylene (PP) resistant to a temperature between 100°C and 150°C, which frame a central barrier layer of ethylene vinyl alcohol (EVOH), said multilayer stock roll being suitable for food contact; - thermoforming and cutting, from said multilayer stock roll, the lid (2), by means of forming moulds, so that said obtained lid (2) comprises, at least, at its lower face (21), a circular groove (5) making up a housing for the seal (3) intended to come into contact with the edge of the upper ring of the container (4), a central portion (23) of said lid (2) forming a convex dome (23a) outwardly raised before vacuumising and able to retract to become concave (23b) during vacuumising, whereas a circular groove (24) surrounding the convex dome (23a) is formed at the upper face (22) of the lid (2), the latter being moreover provided on its entire circumference with a closure rim (6) comprising snap-fitting means (61, 62) able to cooperate with said upper ring of said container (4); - depositing said seal (3) into the circular groove (5) of the lower face of the lid to obtain said sealed, pasteurisable and sterilisable closure system (1); - possibly, cooling said sealed, pasteurisable and sterilisable closure system (1).
2. The method for manufacturing a sealed, pasteurisable and sterilisable closure system (1) according to claim 1, characterised in that said seal (3) is a preformed seal.
3. The method for manufacturing a sealed, pasteurisable and sterilisable closure system (1) according to claim 2, characterised in that said preformed seal (3) is made of a thermoplastic elastomer, TPS-SEBS.
4. The method for manufacturing a sealed, pasteurisable and sterilisable closure system (1) according to claim 1, characterised in that said seal (3) is deposited in liquid or pasty form into said circular groove (5), before a polymerisation phase.
5. A method for manufacturing a sealed, pasteurisable and sterilisable closure system (1), comprising a lid (2) and a seal (3), intended to hermetically close a container (4), in particular a glass jar, said seal (3) being positioned at the edge of an upper ring that said container (4) comprises, said method being characterised in that it comprises, at least, the following steps, considered in sequence: - forming, by extrusion, a multilayer stock roll comprising at least two layers of polypropylene (PP) resistant to a temperature between 100°C and 150°C, which frame a central barrier layer of ethylene vinyl alcohol (EVOH), and a flexible polymer layer constituting said seal, said multilayer stock roll being suitable for food contact; - thermoforming and cutting, from said multilayer stock roll, the lid (2), by means of forming moulds, so that said obtained lid (2) comprises, at least at its lower face (21), a circular groove (5) making up a housing for the seal (3) formed by the flexible polymer layer of the multilayer roll, said seal (3) being intended to come into contact with the edge of the upper ring of the container (4), a central portion (23) of said lid (2) forming a convex dome (23a) outwardly raised before vacuumising and able to retract to become concave (23b) during vacuumising, whereas a circular groove (24) surrounding the convex dome (23a) is formed at the upper face (22) of the lid (2), the latter being moreover provided on its entire circumference with a closure rim (6) comprising snap-fitting means (61, 62) able to cooperate with said upper ring of said container (4); - possibly, cooling said sealed, pasteurisable and sterilisable closure system (1).
6. The method for manufacturing a sealed, pasteurisable and sterilisable closure system (1) according to any one of the preceding claims, characterised in that the polypropylene layer is customisable and comprises colour pigments.
7. The method for manufacturing a sealed, pasteurisable and sterilisable closure system (1) according to any one of the preceding claims, characterised in that the EVOH barrier layer has a thickness between 10 µm and 10% of the total thickness of the multilayer stock roll.
8. The method for manufacturing a sealed, pasteurisable and sterilisable closure system (1) according to any one of the preceding claims, characterised in that said lid (2) obtained by thermoforming also comprises an opening tab (7).
9. The method for manufacturing a sealed, pasteurisable and sterilisable closure system (1) according to any one of the preceding claims, characterised in that said lid (2) obtained by thermoforming also comprises a conical finish circumference (8) forming a flare at the upper face (22) of the lid (2).
10. A sealed, pasteurisable and sterilisable closure system (1) capable of being obtained by implementing the manufacturing method according to any one of the preceding claims, comprising a lid (2) and a seal (3), intended to hermetically close a container (4), in particular a glass jar, said seal (3) being then positioned at the edge of an upper ring that said container (4) comprises, said closure system (1) being characterised in that said lid (2) is manufactured from multilayer plastic material suitable for food contact and comprising at least two layers of polypropylene (PP) resistant to a temperature between 100°C and 150°C and framing an ethylene vinyl alcohol (EVOH) barrier layer, said lid (2) comprising at least, at its lower face (21), a circular groove (5) making up the housing in which the seal (3) is placed, a central portion (23) of said lid (2) forming a convex dome (23a) outwardly raised before vacuumising and able to retract to become concave (23b) during vacuumising, whereas a circular groove (24) surrounding the convex dome (23a) is formed at the upper face (22) of the lid (2), the latter being moreover provided, on its entire circumference, with a closure rim (6) in the form of a skirt comprising snap-fitting means (61, 62) able to cooperate with said upper ring of said container (4).
11. The sealed, pasteurisable and sterilisable closure system (1) according to the preceding claim, characterised in that it is provided with a conical finish circumference (8) forming at the upper face (22) of the lid (2), at the base of the thermoformed lid (2), for cooperation with the external surface of the circular groove (5) of a second closure system (1) during stacking thereof.
12. The sealed, pasteurisable and sterilisable closure system (1) according to claim 10 or claim 11, characterised in that said lid (2) comprises a lateral opening tab (7).
13. The sealed, pasteurisable and sterilisable closure system (1) according to any one of claims 10 to 12, characterised in that said snap-fitting means of the lid (2) able to cooperate with the upper ring of the container (4) consist of a clipping groove (62) running over almost the entirety of the perimeter of the closure rim (6) in the form of a skirt, with the exception of a plurality of portions evenly distributed over said perimeter at which a stiffener (63) is formed.
14. A sealed, pasteurisable and sterilisable closure system (1) according to any one of claims 10 to 12, characterised in that said snap-fitting means of the lid (2) able to cooperate with the upper ring of the container (4) consist of a plurality of internal closure notches (61), evenly distributed over the entire circumference of said skirt.
15. A sealed, pasteurisable and sterilisable closure system (1) according to any one of claims 10 to 14, characterised in that said seal (3) is a preformed seal made of a thermoplastic elastomer, TPS-SEBS.