FR2744425A1 - Water tight container for liquids, especially wine - Google Patents

Abstract

A container (R) for liquids has, at least in the surrounding area around the end opening, a smooth zone (7), having a diameter (d), on the internal wall of the neck (1). The stopper (4) is made of plastic and has an internal skirt which can be elastically fitted against the smooth zone (7) of the neck to ensure the water tightness of the container. Also claimed is a process for the blow extrusion of the claimed container.

Description

The present invention relates to a container for liquid, produced by extrusion blow molding of a relatively rigid plastic material, for example polyethylene. Although not exclusively, the invention is very particularly suitable for the production of such containers, generally called cubitainer, intended for the packaging of wine.

A container of this type comprises a neck, forming an integral part of said container and provided on its external face with a thread. On this neck can be screwed a plug cooperating with said thread and intended to close the end orifice of said neck in a sealed manner vis-à-vis the liquid contained in the container. It will be recalled that the extrusion-blowing method for obtaining such a container consists in extruding an envelope of hot and soft synthetic material inside a mold in at least two pieces, then in blowing air into said envelope. , through the opening of the mold corresponding to the neck of said container.

Generally, these known containers are closed with a multi-component stopper, initially formed by an aluminum shell attached to the neck and at the bottom of which is attached a cork or cardboard washer, responsible for ensuring the 'sealing by taking support on the free edge of said neck. The aluminum shell and the sealing washer are deposited on the neck of the container, after which a crimper rolls said shell over the neck in order to form a closure cap having threads capable of cooperating with the thread of the neck. Optionally, this operation also makes it possible to roll a tamper-evident band on a fastening ring provided for this purpose at the base of said neck.

Such a known closure has many drawbacks.

First of all, the sealing is not very efficient, in particular because the free edge of the neck on which the sealing washer is supported results from the cutting of the core inherent in the extrusion-blowing process. As a result, the free cut edge of the neck may not be absolutely flat so that the seal is poor between said sealing washer and the free edge of the neck. In addition, after the first opening, the seal is degraded and may even be lost. The tamper-evident band is also difficult and sometimes impossible to break. Once broken, this strip, as well as the stopper, have sharp edges. Finally, such a closure requires expensive machines, such as crimpers.

In an attempt to remedy these drawbacks, it has already been proposed to replace the aluminum plugging with plastic plugs. However, such plastic closures also use attached sealing washers, responsible for ensuring the seal at the neck collar. However, such a drink is generally of poor quality, because it has burrs or bar turning defects, so that the seal is itself poor. In addition, when they include a tamper-evident band, these known plastic closures are produced in such a way that said tamper-evident band has a diameter greater than the plastic shell, so that there is a shoulder between this shell and said tamper-evident band. As a result, when the container is intended to contain wine, it is impossible to apply the fiscal stamp straddling the side wall of the shell and the tamper-evident band, in order to the destruction of this stamp at the first opening of the closure.

The object of the present invention is to remedy the drawbacks mentioned above.

To this end, according to the invention, the container for liquid, produced by extrusion blow molding of a plastic material and comprising a neck, forming an integral part of said container and provided on its external face with a thread, as well as a plug. which can be screwed onto said neck by cooperating with said thread to close the end orifice of said neck in a sealed manner with respect to said liquid, is remarkable - in that, at least in the vicinity of said end orifice
tee, the inner wall of said neck has a smooth area
of predetermined diameter; and - in that said plug is also made of plastic
and has an internal skirt that can be applied
elastically against said smooth region of the neck,
ensuring the tightness of said container with respect to said
liquid.

Thus, in accordance with the present invention, the seal is obtained by direct support of the said internal skirt against the smooth zone, of predetermined diameter of the neck, which makes it possible to avoid any seal attached to the plug and bearing on the edge. free of the neck, as well as the drawbacks recalled above and attached to such an attached seal.

Preferably, said internal skirt has a diameter slightly greater than the predetermined diameter of said smooth region of the neck and it is elastically connected both to the external skirt of said cap and to the bottom thereof. For example, the outer skirt and the bottom of the plug are connected by a bellows or the like, part of which constitutes said inner skirt. In the art, such a bellows is generally designated by the word "Biflex".

Usually, said stopper in accordance with the present invention may comprise a tamper-evident band connected to the edge of the outer skirt by tear-away bridges, said tamper-evident band comprising means capable of catching behind a provided fastening ring. on said neck. According to an important feature of the present invention, said tamper-evident band has an outer diameter identical to the outer diameter of said outer skirt, so that the outer walls of said tamper-evident band and said outer skirt are continuous and can allow affix a tax stamp to it, which will be destroyed when the corking opens for the first time.

It will be noted that following wear and aging of the blow-molding mold, it may happen that there appear on the thread, in the joint plane, burrs preventing correct screwing of the plug on the thread bottleneck.

To avoid this drawback and according to an additional characteristic of the present invention, the threads of the threading of the external face of the neck are truncated when said joint plane passes.

It will further be noted that, by the very fact of the method of obtaining containers by extrusion blow molding, the internal surface of the container, including that of said neck, is of poor quality, because the air blowing through said neck, thus that the uncontrolled withdrawals of the material cause defects, such as waves, on the soft internal surface of the container.

Also, it is necessary to provide a special operation to obtain said smooth area of predetermined diameter.

To this end, according to the invention, the method for producing by extrusion blow molding a container for liquid in plastic material, said container comprising a neck forming an integral part of said container and provided on its external face with a thread, as well as a cap which can be screwed onto said neck by cooperating with said thread to close the end orifice of said neck in a sealed manner with respect to said liquid, is remarkable - in that it forms on the internal wall of said neck, at
at least in the vicinity of said end orifice, an area
smooth of determined diameter - in that the said plug is also made of material
plastic; and - in that an internal skirt is formed on said plug
likely to apply elastically against said
smooth area of the neck ensuring the tightness of said
container vis-à-vis said liquid.

To obtain said smooth zone of predetermined diameter, a gauge, the external surface of which is of mirror polished quality, is introduced into said neck, before cooling of the material of the extruded-blown container, presenting said predetermined diameter and discharging soft plastic material. towards the interior of said container. This gives a smooth zone, of annular shape, having several millimeters in height and making it possible to seal from the inside of the neck. The diameter and geometry of this annular zone being essential with regard to sealing, the deformations due to any shrinkage during cooling can be compensated for by anticipating them by the shape of the molding parts, which are for example ovalized. precaution, the necks from these molding parts are circular enough to allow good cooperation between the neck and the internal skirt of the cap.

The screwing of the cap according to the present invention on the neck of the container can be done either manually or automatically using a screwdriver. It is important that the stopper according to the present invention can be screwed manually, as this allows small wine-growers to avoid the investment of one or more screwdrivers.

The figures of the appended drawing will make it clear how the invention can be implemented. In these figures, identical references designate similar elements.

Figure 1 is an axial sectional view showing the plug and the neck according to the present invention, said plug being shown separate from the neck, above the latter.

Figure 2 is a view comparable to Figure 1, the cap being placed on said neck.

FIG. 3 illustrates the production of the smooth zone of predetermined diameter provided, in accordance with the present invention, on the internal face of the neck.

FIG. 4 illustrates the interruption of the threads of the thread of the neck when the joint plane passes.

The neck 1 made of plastic, for example polyethylene, shown in these figures forms an integral part of a container R partially shown in FIG. 4. This container R is intended to contain a liquid, for example wine, and it is produced by an extrusion-blowing process. This neck 1 is provided on its external face lA with a thread 2 and it has an end orifice 3.

The plug 4, made of a relatively elastic plastic material, has an internal thread 5 capable of cooperating with the thread 2 of the neck 1. In the vicinity of the end orifice 3 of the neck 1, the internal wall 6 of said neck has a smooth zone 7 of predetermined diameter d and height h. As for the plug 4, it has an internal skirt 8 having an external cylindrical wall 9 the diameter D of which is slightly greater than the diameter b of the smooth zone 7. In addition, the internal skirt 8 is connected elastically to the bottom 10 as well as 'to the external skirt 11 of said plug 4, owing to the fact that it is formed by a part of a peripheral bellows connecting said bottom 10 to said external skirt 11.

When the plug 4 is put in place by screwing onto the neck 1 (see FIG. 2), the external wall 9 of the internal skirt 8 is applied elastically against the smooth area 7 of the neck 1, ensuring the seal between said neck and said plug.

As illustrated in FIG. 3, the smooth zone 7 of predetermined diameter is formed by the forced introduction of a gauge 12 into said neck 1, when the material of the latter is still hot and plastic, after blowing.

This caliber 12, which has a mirror-polished quality surface, pushes the material of the internal wall 6 towards the interior of the container and gives zone 7 a diameter d, a height h and an appropriate surface condition.

In FIG. 3, below the caliber 12, the corrugations or waves formed on the internal wall 6 by the blowing air have been illustrated.

As can be seen in FIGS. 1, 2 and 4, the neck 1 also has a hooking ring 13 for a tamper-evident band 14 secured to the plug 4 because of the tearable bridges 15 connecting it to the edge 4A of the cap 4, opposite the bottom 10. This tamper-evident band 14 has protrusions 16 capable of catching behind the ring 13. As can be seen in FIGS. 1 and 2, the tamper-evident band 14 has a diameter external identical to that of the external skirt 11 of the plug 4, so that this external skirt 11 and said tamper-evident band 14 form a continuous external lateral surface, only interrupted by the slot 17 in which the bridges 15 are made. It is thus possible to affix a tax stamp (not shown) straddling the outer face 11 and the tamper-evident ring 14.After the first opening of the closure 1.4, the tamper-evident band 14, retained by the ring d hook 13, separates plug 4 by breaking the bridges 15, so that said tax stamp is itself broken.

As shown in FIG. 4, in order to prevent possible plastic burrs from interfering with the screwing of the plug 4 on the neck 1, the threads 2 are interrupted in the joint plane 18 of the neck 1.

After the first opening of the stopper 1.4, the stopper 4 can be screwed back onto the neck 1 as many times as desired, without the quality of the stopper being degraded, since the sealing is simply ensured by the elastic pressure of the external wall 9 of the internal skirt 8 against the smooth zone 7 of the neck 1.

The first opening of the container R is visualized by the fact that the tamper-evident band 14 remains on the neck 1, under the hooking ring 13 while being separated from the stopper 4.

Claims (8)

 vis-à-vis said liquid.  neck (1), ensuring the tightness of said container  apply elastically against said smooth area (7) of the  plastic and has an internal skirt (8) capable of  smooth area (7) of predetermined diameter (d); and - in that said plug (4) is also made of material  (3), the internal wall (6) of said neck (1) has a  ww 1. Container (R) for liquid, produced by extrusion-blowing of a plastic material and comprising a neck (1), forming an integral part of said container and provided on its external face with a thread (2), as well as a plug (4) which can be screwed onto said neck by cooperating with said thread to close the end orifice (3) of said neck in a sealed manner with respect to said liquid, characterized: - in that, at least in the vicinity said end port 2. Container according to claim 1, characterized in that said internal skirt (8) has a diameter (D) slightly greater than the predetermined diameter (d) of said smooth zone (7) of the neck (1) and is connected elastically as well to the outer skirt (11) of said plug than to the bottom (10) thereof. 3. Container according to claim 2, characterized in that the outer skirt (11) and the bottom (10) of the plug (4) are connected by a bellows or the like, part of which constitutes said inner skirt (8). 4. Container according to any one of claims 1 to 3, wherein said cap (4) comprises a tamper-evident band (14) connected to the edge (4A) of the outer skirt (11) by tear-away bridges (15) , said tamper-evident band comprising means (16) capable of being hooked behind a hooking ring (13) provided on said neck (1), characterized in that said tamper-evident band (14) has an outside diameter identical to the outside diameter of said outer skirt (11), so that the outer walls of said tamper-evident band (14) and of said outer skirt (11) are in continuity. 5. Container according to any one of claims 1 to 4, characterized in that the threads of the thread (2) of the external face of the neck (1) are truncated on passing the joint plane (18) of said neck. 6. Container according to any one of claims 1 to 5, characterized in that it is made of polyethylene. 7. Method for producing a container (R) for plastic liquid by extrusion blow molding, said container comprising a neck (1) forming an integral part of said container and provided on its external face (1A) with a thread (2), as well as a plug (4) which can be screwed onto said neck by cooperating with said thread (2) to close the end orifice (3) of said neck in a sealed manner with respect to said liquid, characterized by what is formed on the internal wall (6) of said neck  (1), at least in the vicinity of said end orifice (3),  a smooth zone (7) of determined diameter (d) - in that one also makes said plug (4) in material  plastic; and - in that an internal skirt is formed on said plug (4)  (8) capable of being applied elastically against said  smooth area (7) of the neck ensuring the tightness of said  container vis-à-vis said liquid. 8. Method according to claim 7, characterized in that, to obtain said smooth zone of predetermined diameter (7), is introduced into said neck (1), before cooling of the material of the extruded-blown container, a gauge (12) having said predetermined diameter (d) and capable of discharging soft plastic material towards the interior of said container.