EP0668221B1 - Process for producing a sealed joint - Google Patents

Description

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

In the traditional way today, closing containers by plug prior to their first opening is carried out at by means of a sealable seal, in particular thermally, and more specifically on the one hand, through the cooperation of a seal, put in place all around the top edge of the container neck, sealing the so the container vis-à-vis the outside, and on the other hand, by a support, generally thicker, inserted at the bottom of the cap, the latter coming screw or dip at the upper end of the neck of said container.

The role of the seal is first of all to confer an inviolability on the container before first opening. In addition, it seals container primary vis-à-vis the outside. In addition, he must develop certain compatibility properties with the content it is supposed to isolate from the outside, and for example be food grade when the content is food.

The support is intended to absorb the tolerances between the bottom of the capsule and / or cap 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 ensure some compression with memory effect to precisely allow to absorb these tolerances.

In a known manner, and prior to the installation of the seal at level of the capsule or cap, the support is temporarily secured to the cover with a temporary bonding adhesive. Such adhesive is well known for this application and is generally consisting of glue, or microcrystalline wax or other compounds likely to fulfill the same function.

To date, sealable joints of the type in question are mainly of two types. The first type is a joint without a tongue so that the cover is difficult to tear off or remove after its positioning at the upper edge of the container neck.

In order to overcome this drawback, it has been proposed to provide all of the seal, that is to say the support and cover assembly, of a tongue. Of fact and given the relative thickness of the support, we end up in the most cases with incorrect positioning of the complete seal at the bottom of the capsule cover, further leading to a non-closing waterproof container.

It was then proposed to produce seals consisting of the support and the cover, but not secured to each other. In fact, we do everything first to the establishment, for example by thermal conduction, of the seal at the upper edge of the container neck. Then, we positions the support alone at the bottom of the capsule or stopper. We therefore proceeds in two distinct steps, since support and seal are completely independent of each other. The major disadvantage of this technique is based on the one hand, on its greater complexity of setting on the other hand, and the prohibitive increase in the costs of sealing and capping, in fact requiring setting place of an additional machine on the operating line and therefore, prohibitive for efficient and profitable industrialization.

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

• 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 precut a plurality of supports 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 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 joints themselves, by cutting the strip-seal, substantially in line with the pre-cutouts 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 in starting from a strip assembly likely to form the basis of sealable joints, to make first of all undergo a precut at the level of the only support strip, corresponding to the shape of the subsequent joints, then to remove, following this precuts the "skeleton", that is to say all the falls of the strip constituting the support, so as to obtain a striped strip consisting of a substantially rectangular strip corresponding to the strip within which the only lids are made, at the level of which appear the future supports of the joints according to their shape definitive, then proceed to cut the whole, directly above said joints, according to the desired shape of the lids, that is, by providing these with a tab.

In this way, this relatively simple process to implement, without require additional operation, provides seals which only the cover has a tab, which we could not do until then.

Advantageously and in practice, the positioning of the strip ribbing at the cutting member takes place after centering pre-cut supports at the cutting member, this centering being advantageously carried out by means of a cell wedging, for example on the thickness of the support relative to the strip at within which the only lids are produced, this timing being effected advantageously at the level of the inter-support zones of the strip ragged. This calibration can also be carried out in relation to the appearance of surface of the pre-cut support, or even at a level mark on the strip for this purpose.

The invention also relates to a sealable joint for sealing. of a container with closure by stopper or capsule, comprising a support intended to be positioned at the bottom of the stopper or the capsule and a operculum, temporarily secured to the support before putting it on 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 pull-out tab of the lid when the first opening of the container.

In this way, the joints thus produced, sealable and advantageously heat sealable, can be used for many applications, especially in the food, cosmetic, chemical fields, pharmaceutical, etc., according to an easy implementation, while preserving the required inviolability conditions, further facilitated by uprooting easy to seal.

The manner in which the invention can be realized and the advantages which will emerge more clearly from the example of embodiment which follows given as an indication and not limiting in support of the appended figures.

Figure 1 is a schematic plan view of a joint 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 with temporary connection of the support to the cover, of which FIG. 4 is a view in cross section.

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

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

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

Figure 10 is a schematic representation of an installation likely to carry out the weeding of the strip in accordance with the invention.

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

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

Such a sealable joint basically consists of two parts, namely respectively a support (5) and a cover (2), the support / cover assembly being temporarily secured by means 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 in absorbing tolerances between the bottom of the capsule on the one hand and the upper part of the container neck on the other hand, and, is also intended to ensure a secondary tightness towards the outside, when the cover has been removed, i.e. after 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 material compressible with recovery memory, possibly fitted on its two sides of a polypropylene or other film, in order to give it a some rigidity. It can also be made of cardboard, or even cardboard added with plastic foam, or be made of polystyrene, the examples thus indicated are in no way limiting but purely exemplary.

The cover basically comprises according to the invention a tongue (4) extending it, intended to allow the tearing off of said seal when the container is used for the first time is sealed. This seal, which is therefore sealed and in particular heat-sealed on the upper edge of the container neck is primarily intended 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 was not opened for the first time.

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

In addition, if it is desired that this joint be heat-sealable by induction, it also includes a film made of a material dielectric for transforming high frequency waves (typically 20 kilohertz) that it receives in thermal energy, intended for soften the plastic film, positioned on its face in manhole cover to allow sealing. Typically, we generally uses aluminum film, the thickness of which is example between 20 and 50 micrometers.

In other applications, where the joint is not heat sealable, we position in a known manner either directly on the around the edge of the container neck, or on the face of the lid intended to be applied to said neck, at the level of the contact zone, an adhesive intended to allow sealing.

Finally, the support (5) and the cover (2) are temporarily joined between them in particular either by means of a film, a mesh or dots of temporary bonding adhesive (6), such as glue natural or synthetic, either with micro-crystalline wax advantageously positioned punctually according to 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 joint. according to the invention.

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

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

These two coils are routed to an installation in known itself, intended to allow 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 losses in falls, in order to adapt them to the working formats of the cutting used in the rest of the process. In fact, the bands as well cut-outs may contain one or more joints in width, depending on their dimensions.

The two bands are joined together using an adhesive to temporary bonding, typically glue or micro-crystalline wax, the latter being positioned on the support strip and / or the cover strip, the two strips then being assembled by calendering, the thermoplastic film sealing formed on one of the faces of the seal strip being directed outwards.

A strip (7) shown in FIG. 3 is thus obtained and in section in Figure 4. This strip (7) is then routed at a cutting tool, typically consisting of a cookie cutter, intended for make pre-cuts (8) (see figure 5), corresponding to the shape and the dimension of the support (5) of the final joint. These precuts (8), as well that can be seen in Figure 6, are limited to the single support and do not affect the strip (9), that the cutting tool comes outcrop.

The strip (7) thus produced and provided with these precuts (8) is routed to a facility (16) called weeding, and materialized in FIG. 10, intended to make it possible to remove from said strip the "skeleton" (12) ie the periphery of the supports (5) defined by the pre-cuts (8), so as to obtain a striped strip (11) shown in Figure 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 initiation of weeding, i.e. the removal of the skeleton (12) is done manually, then, once the roller (15) has started, it takes place automatically, speed and tension being adjusted of course, programmable.

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

The strip (11) thus ragged is then routed at a another cutting member, typically of the punch-die type, or a another cookie cutter, intended to produce, directly above the supports (5) the cutting of the single cover strip (9), i.e. corresponding substantially the same shape and size as the supports (5) but further comprising cutting the tongue (4), and this in the extension of the cover itself.

This cutting is carried out after prior centering of the cutting at the level of 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 strip (9).

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

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 a piston, ensuring the positioning of the seal made at the bottom of said capsule.

A joint of the type described in the Figures 1 and 2 quickly and automatically, without requiring a setting particularly heavy work.

At the same time, the joint obtained turns out to be easier to install, since no tab has to be positioned at the bottom of the capsule plugging, and also allows the cap to be torn off also much easier.

Claims (7)

1. Method for producing a sealable gasket for sealing a container that is to be closed, by a stopper or cap, consisting:

   first of all, in producing a first strip, called a backing strip, intended to allow a number of gasket backings (5) to be produced, the said backings themselves being intended to be positioned at the closed end of the cap or of the stopper;

   then in producing a second strip called a film strip (9), intended to allow a number of films (2) to be produced, these being intended to be sealed to the upper edge of the neck of the container;

   then in reversibly securing these two strips together using an adhesive (6) that forms a temporary bond,
   characterized in that:

   the assembly thus obtained is subjected to the action of a cutting-out member intended to precut a number of backings (5) exclusively within the backing strip, with the shape and size desired for the gasket backing;

   then in subjecting the strip thus obtained, with its precuts (8) to a cleaning-up operation intended to remove from the said backing strip the material around the edges (12) of the backings, which edging material consists of the leftovers of the constituent backing strip surrounding the precuts (8) defining what will be the backings;

   and finally in subjecting the cleaned-up strip (11) thus obtained to the action of a cutting-out member intended to individualize the actual gaskets by cutting out the film strip (6) more or less vertically in line with the precuts in the backing, to the size of the said precuts in the backing, the only difference being that for each of the gaskets there is an extension (4) intended to act as a tab that can be gripped for tearing the said film, when the latter is in place on the neck of the container.
2. Method for producing a sealable gasket according to Claim 1, characterized in that the cleaned-up strip (11) is positioned at the cutting-out member after the precut backings have already been centred at the said cutting-out member.
3. Method for producing a sealable gasket according to Claim 2, characterized in that centring is carried out using a cell which looks at the thickness of the precut backing (5) compared with the film strip (9), this looking advantageously taking place at the regions between backings on the cleaned-up strip.
4. Method for producing a sealable gasket according to Claim 2, characterized in that centring takes place using a cell looking at the surface appearance of the gasket, or at a mark formed for this purpose on the film strip (9).
5. Sealable gasket for sealing a container that is to be closed, by a stopper or cap, comprising a backing (5) intended to be positioned in the closed end of the stopper or of the cap and a film (2) secured temporarily to the backing prior to its placement in the cap, and to the sealing of the container, characterized in that only the film (2) has an extension (4) intended to constitute a tab for tearing off the film when the container is opened for the first time.
6. Sealable gasket according to Claim 5, characterized in that it can be sealed by the action of heat.
7. Sealable gasket according to Claim 6, characterized in that it can be heat-sealed by induction, and that for this to be possible it comprises a film made of a dielectric material, and especially made of aluminium.

Images