EP0668221A1 - Process for producing a sealed joint for sealing a container closed by a stopper or a cap and sealed joint so produced - Google Patents

Abstract

The procedure consists of pre-cutting circular discs (5,2) for the seal from two separate strips of material, and joining them together with a temporary adhesive (6) so that they are accurately aligned. One of the discs (5) forms a compressing backing layer of plastics foam or cardboard. The other, which forms the sealing, is of aluminium film which is plastics coated to stick it to the rim of the container and equipped with a tongue (4) for removing it.

Description

The invention relates to a new method for producing a sealable seal, intended to allow the closure of a container with closure by cap or capsule. It also relates to the sealable joints obtained by this process.

In the traditional way today, the closure of containers by a cap prior to their first opening is carried out by means of a sealable seal, in particular thermally, and more specifically on the one hand, by the cooperation of a seal, placed place around the entire periphery of the upper rim of the container neck, thereby sealing the container from the outside, and on the other hand, by a support, generally thicker, inserted at the bottom of the stopper, this from screwing or dipping at the upper end of the neck of said container.

The role of the seal is first of all to impart inviolability to the container before its first opening. In addition, it ensures the primary sealing of the container vis-à-vis the outside. In addition, it must develop certain properties of compatibility with the content that it is supposed to isolate from the outside, and for example be of food quality when the content is food.

As for the support, it is intended to absorb the tolerances between the bottom of the capsule and / or of the stopper and the upper part of the neck of the container, and in addition, to ensure secondary sealing, as soon as the cover has been opened or removed. It is therefore likely to provide a certain compression with memory effect to precisely allow these tolerances to be absorbed.

In known manner, and prior to the installation of the seal at the level of the capsule or the stopper, the support is temporarily secured to the cover by means of a temporary bonding adhesive. Such adhesive is well known for this application and generally consists of glue, or microcrystalline wax or other compounds capable of fulfilling the same function.

To date, the sealable seals of the type in question are mainly of two types. The first type is a seal without a tongue so that the cover is difficult to tear off or remove after it has been put in place at the upper edge of the neck of the container.

In order to overcome this drawback, it has been proposed to provide the entire seal, that is to say the support and cover assembly, with a tongue. In fact and taking into account the relative thickness of the support, in most cases this leads to an incorrect positioning of the complete seal at the bottom of the cap of the capsule, resulting moreover in an unsealed closure of the container.

It was then proposed to produce seals made up of the support and the cover, but not secured to one another. In fact, the first step is to set up, for example by thermal conduction, the cover at the upper rim of the neck of the container. Then, the support is positioned alone at the bottom of the capsule or the stopper. We therefore proceed in two distinct steps, since support and cover are completely independent of each other. The major drawback of this technique rests on the one hand, on its greater complexity of implementation, and on the other hand, the prohibitive increase in the costs of carrying out the sealing and capping, indeed requiring the setting in place of an additional machine on the operating line and therefore unacceptable for efficient and profitable industrialization.

In fact, the invention proposes a new type of seal that can be sealed, in which only the cover is provided with a tear-off tab. It also proposes a method for producing such a joint.

• tout d'abord, à réaliser une première bande, dite bande-support, destinée à permettre la réalisation d'une pluralité de supports de joint, lesdits supports étant destinés à être positionnés au fond de la capsule ou du bouchon ;
• puis à réaliser une seconde bande, dite bande-opercule, destinée à permettre la réalisation d'une pluralité d'opercules, destinés à être scellés sur le rebord supérieur du col du récipient ;
• puis à solidariser réversiblement la bande-support à la bande-opercule au moyen d'un adhésif à liaison temporaire.

This process for producing a sealable seal for closing a container with a stopper or cap consists of:

• firstly, to produce a first strip, called the support strip, intended to allow the production of a plurality of seal supports, said supports being intended to be positioned at the bottom of the capsule or of the stopper;
• then to produce a second strip, known as a cover strip, intended to allow the production of a plurality of covers, intended to be sealed on the upper rim of the neck of the container;
• then reversibly securing the support strip to the cover strip using a temporary bonding adhesive.

• l'ensemble ainsi obtenu est soumis à l'action d'un organe de découpe, destiné à prédécouper une pluralité de supports au seul sein de la bande-support selon la forme et les dimensions souhaitées du support de joint ;
• puis à faire subir à la bande ainsi obtenue munie de ses prédécoupes un échenillage, destiné à ôter de ladite bande-support le pourtour des supports, pourtour constitué par le reste de la bande constitutive du support entourant les prédécoupes ;
• et enfin à soumettre la bande échenillée ainsi obtenue à l'action d'un organe de découpe destiné à individualiser les joints proprement dits, par découpe de la bande-opercule, sensiblement à l'aplomb des pré-découpes du support, selon les dimensions desdites prédécoupes du support au ménagement près pour chacun des joints d'un prolongement, destiné à faire office de languette de préhension et d'arrachage dudit opercule, lorsque ce dernier est mis en place au niveau du col du récipient.

It is characterized in that:

• the assembly thus obtained is subjected to the action of a cutting member, intended to pre-cut a plurality of supports within the support strip alone according to the desired shape and dimensions of the seal support;
• then subjecting the strip thus obtained provided with its precuts a weeding, intended to remove from said support band the periphery of the supports, periphery constituted by the rest of the constituent band of the support surrounding the precuts;
• and finally to subject the ribbed strip thus obtained to the action of a cutting member intended to individualize the seals proper, by cutting the strip-seal, substantially in line with the pre-cuts of the support, according to the dimensions said precuts of the support close to each of the joints of an extension, intended to act as a gripping and tearing tab of said cover, when the latter is put in place at the neck of the container.

In other words, the invention consists of starting from an assembled strip capable of constituting the base of sealable joints, of first undergoing a precut at the level of the single support strip, corresponding to the shape of the subsequent joints, then removing, following this precut the "skeleton", that is to say all of the falls of the strip constituting the support, so as to obtain a striped strip consisting of a strip substantially rectangular corresponding to the strip within which the only lids are made, at which appear the future supports of the joints according to their final shape, then to proceed to cut the assembly, directly above said joints, according to the desired shape of the lids, that is to say, by providing them with a tab.

In this way, this relatively simple process to implement, without requiring any additional operation, makes it possible to obtain seals of which only the cover is provided with a tongue, which we hitherto did not know how to do.

Advantageously and in practice, the positioning of the ribbed strip at the cutting member is effected after prior centering of the precut supports at the cutting member, this centering being advantageously carried out by means of a wedging cell. , for example on the thickness of the support relative to the strip within which the only lids are made, this setting advantageously taking place at the inter-support zones of the striped strip. This setting can also be carried out in relation to the surface appearance of the precut support, or even at the level of a mark provided on the strip for this purpose.

The invention also relates to a sealable seal for closing a container with closure by stopper or capsule, comprising a support intended to be positioned at the bottom of the stopper or of the capsule and a cover, temporarily secured to the support prior to its placing. in place within the cap, and at the lid of the container. It is characterized in that the cover comprises an extension intended to constitute the tear-off tab of the cover during the first opening of the container.

In this way, the seals thus produced, sealable and advantageously heat-sealable, can be used for numerous applications, in particular in the food, cosmetic, chemical, pharmaceutical, etc. fields, according to an easy implementation, while preserving the required inviolability conditions, further facilitated by easy removal of the cover.

The manner in which the invention can be implemented and the advantages which ensue therefrom will emerge more clearly from the example of embodiment which follows, given by way of indication and without limitation in support of the appended figures.

Figure 1 is a schematic plan view of a seal according to the invention.

Figure 2 is a cross-sectional view of Figure 1.

Figure 3 is a schematic representation of a strip of the material of the seal obtained after assembly by adhesive temporarily bonding the support to the cover, of which Figure 4 is a cross-sectional view.

Figure 5 is a view similar to Figure 3 after pre-cutting, of which Figure 6 is a cross-sectional view.

Figure 7 is a view similar to Figures 3 and 5 after weeding, Figure 8 is a sectional view.

Figure 9 is a representation of the strip after final cutting of the cover, of which Figure 2 is a transverse sectional representation.

Figure 10 is a schematic representation of an installation capable of performing the weeding of the strip according to the invention.

There is shown in Figure 1 a sealable seal, in particular heat-sealable according to the invention. According to an advantageous characteristic, the seal bearing the general reference (1) in FIG. 1 is heat-sealable by induction, that is to say that it comprises at least one film made of a dielectric material, capable of transforming high frequency waves into thermal energy, to allow the temperature rise of a thermo-plastic film associated with it, to allow its softening and its sealing on the upper edge of the neck of a container.

Such a seal (1) is in fact intended to allow the sealing and sealing of a container, the closure of which is obtained by means of a capsule or stopper, itself screwed or clipped at the neck of said container .

Such a sealable seal is basically made up of two parts, namely a support (5) and a cover (2) respectively, the support / cover assembly being temporarily secured by means of a temporary bonding adhesive (6) (see figure 2).

The support (5) is intended to be inserted, in particular by force, at the bottom of the closure cap. As already said, it has a role of absorbing the tolerances between the bottom of the capsule on the one hand and the upper part of the neck of the container on the other hand, and is also intended to ensure a secondary seal with respect to outside, when the cover has been removed, ie after the first use or first opening of said container.

This support, with a typical thickness of between 0.5 and 4 mm, can be made of expanded polyethylene or another compressible material with recovery memory, possibly provided on its two sides of a polypropylene or other film, to give it a certain rigidity. It can also be made of cardboard, or even cardboard with added plastic foam, or even be made of polystyrene, the examples thus indicated are in no way limitative but purely illustrative.

The cover basically comprises according to the invention a tongue (4) extending it, intended to allow the tearing off of said cover during the first use of the container at which it is sealed. This seal, which is therefore sealed and in particular heat-sealed on the upper edge of the container neck, is intended primarily to ensure the inviolability of the contents of the container. In addition, by its sealing, it also provides a primary seal as long as said container has not been opened for the first time.

This cover must also be compatible, either with the content of the container, especially when it is food, or with the container itself, depending on whether it is made of glass or plastic.

In addition, if this joint is to be heat-sealed by induction, it also includes a film made of a dielectric material intended to transform the high frequency waves (typically 20 kilohertz) which it receives into thermal energy, intended for soften the plastic film, positioned on its face opposite the container to allow sealing. Typically, an aluminum film is generally used, the thickness of which is for example between 20 and 50 micrometers.

In other applications, in which the seal is not heat-sealable, in known manner is positioned either directly on the around the edge of the neck of the container, or on the face of the cover intended to be applied on said neck, at the contact area, an adhesive intended to allow sealing.

Finally, the support (5) and the cover (2) are temporarily joined together, in particular either by means of a film, a mesh or dots of temporarily bonded adhesive (6), such as in particular natural or synthetic glue, either by means of micro-crystalline wax advantageously positioned punctually at a multitude of points, almost uniformly distributed. This micro-crystalline wax is advantageously absorbed during heat-sealing in a thin film of paper or cardboard respectively associated either with the support (5) or with the cover (2), taking into account its liquefaction.

There will now be described the process for producing such a seal according to the invention.

A strip of a material intended to constitute the support is first produced, for example by extrusion of low density polyethylene, followed by an expansion of the latter and laminating of two polypropylene films, said strip then being stored under the form of a coil.

In parallel, a strip of a material intended to constitute the cover is produced by assembling a thermo-plastic film intended to allow the subsequent sealing, possibly associated with an aluminum film (9) or even a sheet of paper of additional cardboard, intended to absorb the temporary bonding adhesive during heat-sealing. In certain particular applications, in particular food, the complex constituting the cover may also include a film of parchment paper or equivalent. This strip is also advantageously stored in the form of a reel.

These two coils are routed at an installation known per se, intended to allow the reversible and temporary joining of the two bands. Prior to their assembly, the two strips are cut to the same width, in order to minimize the loss of falls, in order to adapt them to the working formats of the cutting tools used in the rest of the process. In fact, the strips thus cut are capable of being able to contain one or more joints in width, depending on their dimensions.

The two strips are joined together by means of a temporary bonding adhesive, typically glue or micro-crystalline wax, this being positioned on the support strip and / or the seal strip, both the strips then being assembled by calendering, the thermoplastic sealing film formed on one of the faces of the cover strip being directed towards the outside.

A strip (7) shown in FIG. 3 and in section in FIG. 4 is thus obtained. This strip (7) is then conveyed at the level of a cutting tool, typically constituted by a punch, intended for make pre-cuts (8) (see Figure 5), corresponding to the shape and size of the support (5) of the final joint. These precuts (8), as can be seen in FIG. 6, are limited to the single support and do not affect the strip (9), which the cutting tool is flush with.

The strip (7) thus produced and provided with these precuts (8) is routed to an installation (16) called weeding, and materialized in FIG. 10, intended to allow the removal of said strip from the "skeleton". "(12), that is to say the periphery of the supports (5) defined by the precuts (8), so as to obtain a striped strip (11) shown in FIG. 7.

This installation (16) firstly comprises a first roller at which the strip (7) fitted with its precuts (8) is mounted, then a second roller (15) at which the skeleton (12) is wound, and finally a third roller (14) at which the ribbed strip (11) is wound, the position materialized by the letter A corresponding to the ideal position for removing the circumference or skeleton (12), the position materialized by the letter B being the limit position for removal of said skeleton, beyond which the removal of said skeleton is no longer carried out under good conditions.

The priming of the weeding, that is to say the removal of the skeleton (12) is carried out manually, then, once the roller (15) has started, it is carried out automatically, the adjustment of the speeds and voltages being of course programmable.

In this way, there is obtained (see FIG. 8), a base (9) constituted by the strip-seal, on which are positioned, at regular intervals, the supports (5) already in shape.

The strip (11) thus ragged is then routed at the level of another cutting member, typically of the punch-die type, or another punch, intended to carry out, at the base of the supports (5), the cutting of the single cover strip (9), that is to say corresponding substantially to the same shape and dimension as the supports (5) but also comprising the cutout of the tongue (4), and this in the extension of the cover himself.

This cutting is carried out after prior centering of the cutting member at the supports (5) already cut, for example by means of a photoelectric cell detecting the variation in thickness in the inter-support zone with respect to the band (9).

Cutting the shape of the cover may slightly exceed the dimension of the support, thus materializing a crown (3) coplanar with the cover (2) itself, which can also possibly facilitate the sealing operation. However, it can correspond to the size of the support.

In some cases, the seal is placed directly at the level of the capsule during its cutting, the cutting member being in this case provided with a piston, ensuring the positioning of the seal produced at the bottom of said capsule.

A joint of the type described in FIGS. 1 and 2 is thus thus obtained directly and quickly, automatically, without requiring particularly heavy implementation.

At the same time, the seal obtained turns out to be easier to put in place, since no tab has to be positioned at the bottom of the closure cap, and also allows the cap to be torn off also much easier.

Claims (7)

1 / Method for producing a sealable seal for closing a container with closure by cap or capsule, consisting of: - first of all, to produce a first strip, called the support strip, intended to allow the production of a plurality of seal supports (5), said supports themselves being intended to be positioned at the bottom of the capsule or plug; - Then to produce a second strip, called a strip-seal (9), intended to allow the production of a plurality of covers (2), intended to be sealed on the upper rim of the neck of the container; - then reversibly securing these two strips by means of an adhesive (6) with temporary connection, characterized in that: - The assembly thus obtained is subjected to the action of a cutting member, intended to pre-cut a plurality of supports (5) within the support strip alone according to the shape and the desired dimensions of the seal support; - Then subjecting the strip thus obtained provided with its precuts (8) a weeding, intended to remove from said support band the periphery (12) of the supports, periphery constituted by the rest of the constituting support band surrounding the precuts (8) defining the subsequent supports; - And finally to subject the ribbed strip (11) thus obtained to the action of a cutting member, intended to individualize the seals themselves, by cutting the strip-seal (9), substantially in line with the precuts of the support, according to the dimensions of said pre-cutouts of the support, except for each of the joints of an extension (4), intended to act as a gripping and tearing tab of said cover, when the latter is put in place at the level of the container neck. 2 / A method for producing a sealable joint according to claim 1, characterized in that the positioning of the ribbed strip (11) at the cutting member is effected after prior centering of the precut supports at the said member cutting. 3 / A method for producing a sealable joint according to claim 2, characterized in that the centering is carried out by means of a cell wedging on the thickness of the precut support (5) relative to the strip-seal ( 9), this setting advantageously taking place at the inter-support zones of the striped strip. 4 / A method for producing a sealable joint according to claim 2, characterized in that the centering is carried out by means of a cell wedging on the surface appearance of the joint, or on a mark provided for this purpose on the cover strip (9). 5 / Sealable seal for closing a container with closure by stopper or capsule, comprising a support (5) intended to be positioned at the bottom of the stopper or the capsule and a cover (2), temporarily secured to the support prior to its positioning within the cap, and at the sealing of the container, characterized in that the cover (2) has an extension (4) intended to constitute a pull-out tab for the cover during the first opening of the container. 6 / seal seal according to claim 5, characterized in that it is heat sealable. 7 / seal seal according to claim 6, characterized in that it is heat sealable by induction, and that it comprises for this purpose a film made of a dielectric material, and in particular aluminum.

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