Closure device and container equipped with same

Abstract

The invention concerns a method which consists in moulding a plastic cap (1) and steps which consist in: providing, proximate to an inner surface of base web (7) of the cap (1), a first layer (6) of material impermeable to a predetermined gas or gases and depositing, on said first layer (6) set in the cap (1), a second layer (8) made of an elastic material different from that of the first layer (6), said second layer (8) being designed to form the joint, by isolating the first layer from ambient air.

Description

[0001] The invention relates to a method for making a closure device for a container. The invention also relates to a closure device for a container and to a container equipped with such a device.

[0002] It is known to make containers for liquids, such as bottles for drinks, by extrusion/blowing or injection/blowing of plastics material. It is known to equip such bottles with a cap, likewise made of plastics material. It is essential that these containers be closed hermetically with a view to allowing prolonged storage of the products that they contain. In effect, it should be avoided that oxygen can penetrate inside a closed container in order to limit the risks of oxydation of its contents. In addition, in the case of containers containing a gaseous liquid, such as beer or a carbonated drink, it should be avoided that the gas contained in the liquid escape outside the container. The transfers between the interior and the exterior of a container should also be limited in order to prevent a degradation of the organoleptic properties or of the taste of a drink such as a fruit juice or mineral water. For the principal part of the container, such as a bottle made of plastics material, it is known to prevent the migrations of gas from or towards the interior volume of the container by affixing an internal or external coating, for example of silica oxide or polyamide, on this body.

[0003] In that case, the leakages of gas are concentrated at the level of the cap of the closure device. In effect, the cap cannot be gas-tight by itself. If it is equipped with a gas-tight pellet, the material used for this pellet is relatively rigid, with the result that it cannot follow the shape of the neck with which it must cooperate sufficiently precisely, this inducing a risk of leakage at the interface between the neck and this pellet. On the contrary, if a supple material is used for constituting a seal as in EP-A-0 970 893, this material does not make it possible to limit efficiently the leakages of gas by permeability through the cap. In effect, in this state of the art, the same plastics material, for example of the ethylene/l-butene copolymer type, may possibly be applied in successive layers but is not completely tight since its coefficient of oxygen transfer remains non-zero. Moreover, the seal obtained is not always satisfactory. These imperfect properties of barrier or of seal are a consequence of the necessary compromises to be employed in order to make the same material perform hardly compatible functions.

[0004] It has been envisaged to equip a cap with an aluminium foil on which would be affixed a polypropylene foam intended to come into abutment against the neck of a bottle. Such a cap does not give satisfaction insofar as an interstice is created between the aluminium foil, which is floating, and the bottom web of the cap, this interstice promoting the development of germs and/or bacteria likely to contaminate the contents of the container. In addition, the cost price of such a device is high. Finally, the aluminium foil proves to be a hindrance when such a cap is reprocessed, as it must be processed differently from the plastics material.

[0005] It is a more particular object of the invention to overcome these drawbacks by proposing an economical method for making a closure device which makes it possible to render a container tight, particularly by avoiding the migrations of gas from inside the container towards the outside or from outside towards the inside.

[0006] In this spirit, the invention relates to a method for making a closure device in which a cap moulded from plastics material is equipped with a seal adapted to be arranged in abutment against the neck of a container. This method is characterized in that it comprises steps consisting in:

[0007] positioning, in the vicinity of an inner surface of a bottom web of the cap a first layer of material impermeable to a predetermined gas or gases, and

[0008] depositing on this first layer, in place in this cap, a second layer made of an elastic material and different from the material constituting the first layer, this second layer being intended to form the seal, by isolating this first layer from the ambient atmosphere.

[0009] Thanks to the method of the invention, the development of germs in the vicinity of the impermeable layer is avoided by isolating the latter from the ambient atmosphere thanks to the second layer which forms the seal. This second layer is advantageously made by overmoulding on the first layer, this guaranteeing its adaptation to the exact geometry of the interior of the button (sic). According to the invention, the material of the first layer may be chosen principally for the gas-tight properties of this first layer, while the material of the second layer may be chosen specifically as a function of its elasticity in order to perform its role of seal efficiently.

[0010] According to a first advantageous form of embodiment of the invention, the method comprises a step consisting in overmoulding, by injection or compression, the first layer against the web. Thanks to this aspect of the invention, no interstice can be created between the first layer, which is impermeable, and the bottom web of the cap.

[0011] According to another advantageous form of embodiment of the invention, there is provided the positioning of a plate, pre-cutout in material impermeable to the gas, in the vicinity of the bottom web of the cap, this plate then being immobilized against this web by the deposit of the second layer.

[0012] According to another advantageous form of embodiment of the invention, the first layer is projected onto the inner surface of the bottom web of the cap.

[0013] Whatever the form of embodiment considered, there may be provided a prior step of moulding of the cap, the positioning of the first layer and the deposit of the second layer being effected continuously, immediately after the moulding of the cap. This continuous aspect of the method avoids the possible deposit of impurities on the bottom web of the cap, during an intermediate storage step.

[0014] The invention also relates to a closure device capable of being manufactured in accordance with the method described hereinabove and, more precisely, to a closure device which comprises a layer of material impermeable to a predetermined gas or gases interposed between a seal and the bottom web of its cap, this layer being isolated from the ambient atmosphere by this cap and this seal which is made of a material different from that of the layer of gas-impermeable material.

[0015] According to advantageous aspects of the invention, this method and this device comprise one or more of the following characteristics:

[0016] The layer of impermeable material comprises a layer of silica oxide, or of carbon in diamond or amorphous form, integrated in a multi-layer complex arranged against the bottom web and covered with a layer of elastic material forming the seal.

[0017] The seal is made on the basis of a ethyl vinyl acetate (EVA) copolymer, of elastomer, in particular a derivative of polyamide (PA), of polyamide and/or polyether copolymer. This seal may also receive, in its composition, a component which renders it adapted to absorb a gas such as oxygen, in particular the oxygen of the “top empty space” of a bottle and/or the oxygen coming from the product contained in a bottle.

[0018] The seal is in the overall form of a disc, with a radius substantially equal to the inner radius of the cap, with the result that it efficiently isolates the layer of impermeable material by simply being positioned in the cap. The layer of impermeable material may thus be totally isolated from the outside medium, this allowing this layer to be made with specific materials which could not necessarily be used alone as they are capable of degrading upon contact with the product or with the air.

[0019] Finally, the invention relates to a container for liquid, particularly a bottle made of plastics material, equipped with a closure device such as described hereinabove. Such a container makes it possible to store the product that it contains for a relatively long period of time and without risk of alteration.

[0020] The invention will be more readily understood and other advantages thereof will appear more clearly in the light of the following description of three closure devices in accordance with the invention and of their respective methods of manufacture, given solely by way of example and made with reference to the accompanying drawings, in which:

[0021] FIG. 1 is a longitudinal section in perspective of a closure device according to the invention, during a first step of manufacture.

[0022] FIG. 2 is a view similar to FIG. 1 during a second step of manufacture.

[0023] FIG. 3 is a view on a larger scale of detail III in FIG. 2.

[0024] FIG. 4 is a view similar to FIG. 1 during a third step of manufacture.

[0025] FIG. 5 is a view similar to FIG. 1 at the issue of the method for manufacturing the device.

[0026] FIG. 6 is a view in detail on a larger scale of detail VI in FIG. 5.

[0027] FIG. 7 is a schematic representation of the closure device of FIGS. 1 to 6, mounted on the neck of a container.

[0028] FIG. 8 is a schematic representation of an installation for manufacturing the device of FIGS. 1 to 6.

[0029] FIG. 9 is a view similar to FIG. 2 for a device in accordance with a second form of embodiment of the invention.

[0030] FIG. 10 is a view similar to FIG. 9 during a third step of manufacturing the cap.

[0031] FIG. 11 is a view similar to FIG. 9 at the issue of manufacture of the device.

[0032] FIG. 12 is a view on a larger scale of detail XII in FIG. 11.

[0033] FIG. 13 is a view similar to FIG. 2 for a device in accordance with a third form of embodiment of the invention, and

[0034] FIG. 14 is a view similar to FIG. 6 for the device of FIG. 13.

[0035] The cap 1 shown in FIGS. 1 to 7 is intended to be mounted on a bottle 2 provided with a neck 3 equipped with an outer threading 4.

[0036] The cap 1 is provided with an inner thread 5.

[0037] The cap 1 is moulded by compression in a barrel mould 101 of an installation 100 for continuously manufacturing closure devices according to the invention. The cap 1 is moulded from rigid polyethylene, rigid polypropylene, rigid polyamide or from an equivalent material.

[0038] Taking into account the manufacturing tolerances of the neck 3 and of the cap 1, it is necessary to provide a seal between this neck and this cap.

[0039] Before such a seal is placed in position, an impermeable complex 6 cut out in the form of a disc is introduced against the inner surface 71 of the bottom web 7 of the cap 1.

[0040] As is more clearly seen in FIG. 3, the complex 6 comprises a core 61 made of polypropylene or PET coated, on a face intended to come into contact with the surface 71, with an adherence layer 62 made of polyethylene or polypropylene. On its opposite face, the core 61 is coated with a layer 63 of silica oxide which renders the complex 6 tight to oxygen and to carbon dioxide.

[0041] The complex 6 is placed in position in the cap 1, as represented by arrow F1, by means of an automatic barrel device 102 supplied via a chute 103 from the mould 101.

[0042] The afore-mentioned complex 6 might also be formed by:

[0043] a very fine deposit, on a support disc, of diamond carbon or of amorphous carbon, this deposit being effected by a plasma deposit or pulverization technique. These deposit techniques are also applied to the deposit of the layer 63 of silicon oxide. In a variant, a varnish or a lacquer forming barrier against the gas(es) may also be applied on a support.

[0044] a particular material, of PVC, PVDC, EVOH, PA type or a mixture of these materials. PEN (polyethylene napthalate), PVA (polyvinyl alcohol), the acrylate copolymers of PAN (polyacrylonitrite), PPMA (polymethylmethacrylate), the copolymers of butadiene, styrene, BOPP (bi-oriented polypropylene) or one of the mixtures thereof may also be used.

[0045] A seal 8 made of vinyl acetate (EVA) copolymer, of elastomer, particularly derived from polyamide (PA), or in another elastic material, is overmoulded on the complex 6 by compression thanks to a plunger 9 introduced in the cap 1, as represented by arrow F2 in FIG. 4. The material intended to form the seal 8 is deposited on the complex 6 before the introduction of the plunger 9 in the cap 1. The seal 8 may also be made of PA copolymer and/or polyether.

[0046] The seal 8 is formed so that it completely isolates and immobilizes the complex 6 against the surface 71, which has the effect of preventing any development of germs or of bacteria.

[0047] As is seen in FIG. 6, the seal 8 may form a skirt filling a possible annular space remaining between the complex 6 and the cap 1.

[0048] The seal 8 is in the form of a disc and R denotes its radius. R′ denotes the inner radius of the cap 1 in its parts distinct from the thread 5. The radii R and R′ are substantially equal since the seal 8 extends up to contact with the annular partition 11 of the cap 1.

[0049] The operation of overmoulding of the seal 8 on the complex 6 takes place in a barrel mould 104 supplied by a chute 105 from the device 102.

[0050] As is more particularly visible in FIGS. 6 and 7, when the closure device formed by elements 1, 6 and 8 is terminated, it comprises a supple seal 8 capable of easily adapting itself to the geometry of the neck 3, while the complex 6, and in particular its layer 63, opposes any migration of gas from the internal volume V of the bottle 2 towards the outside, this being represented by arrows F3, and from the outside towards this volume, this being represented by arrows F4 in FIG. 7.

[0051] In the second form of embodiment of the invention shown in FIGS. 9 to 12, elements similar to those of the first embodiment bear identical references increased by 200. In this form of embodiment, a cap 201 is provided with a bottom web 207 of which 271 denotes the inner surface.

[0052] On this inner surface there is deposited a quantity Q of plastics material impermeable to oxygen and to carbon dioxide. It may be question of polyvinylchloride (PVC), of polyvinylidene chloride (PVDC), of ethylene vinyl alcohol (EVOH), of polyamide or of a mixture based on one of these products. In a variant, polyethylene naphthalate (PEN), polyvinyl acohol (PVA), acrylate copolymer of polyacrylnitrile (PNA) type, polymethylmethacrylate (PPMA), copolymer of butadiene, styrene, bi-oriented polypropylene (BOPP), may be used for this layer.

[0053] A plunger 110 is then applied on the quantity Q of material to distribute it and compress it so as to form a layer 206 of impermeable material covering the surface 271. In other words, the layer 206 is overmoulded inside the cap 201.

[0054] A seal 208 of the type such as seal 108 of the first embodiment is then made in the manner described with reference to FIG. 4 of the first embodiment, which makes it possible to obtain the structure shown in FIGS. 11 and 12 which comprises a first gas-impermeable layer 206 applied on the bottom web 207 of the cap 201, and a second layer 208, elastically deformable and capable of being adapted to the exact geometry of the neck of a bottle and, more generally, of any container.

[0055] As previously, the impermeable layer 206 is embedded against the bottom web 207 of the cap 201 by the layer forming seal 208, with the result that it is efficiently isolated from outside pollutions.

[0056] As previously, the radii R of the seal 208 and R′ of the bottom web 207 are substantially equal.

[0057] The closure device of this second form of embodiment may be obtained thanks to an installation similar to that shown in FIG. 8, the device 102 for positioning the complex 6 of the first embodiment being replaced by a barrel mould, in which the layer 206 is overmoulded.

[0058] In the third form of embodiment of the invention shown in FIGS. 13 and 14, elements similar to those of the first embodiment bear identical references increased by 300. In this embodiment, a cap 301 is provided with a bottom web 307 of which 371 denotes the inner surface.

[0059] As shown in FIG. 13, a layer 306 forming barrier to the migration of gases such as oxygen and/or carbon dioxide, is projected thanks to a nozzle 311 on the surface 371, as represented by arrows F5.

[0060] The layer 306 is thus obtained by a deposit of silica oxide. It may also be question of a barrier varnish. The layer 306 might be obtained by metallization. Although this has not been shown, the layer 306 may cover all or part of the inner surface of the annular partition of the cap.

[0061] After the deposit of the layer 306, a seal 308 is overmoulded on the bottom of the cap 301, in manner similar to that described with reference to the first embodiment, this seal efficiently isolating the layer 306 from the ambient atmosphere.

[0062] As previously, the layer forming the seal 308 is made of an elastically deformable material adapted to create a tight abutment on the neck of a container.

[0063] The fact of moulding the cap 1, 201 or 301 by compression allows an individualized monitoring of the caps and an efficient quality control of the process for positioning the impermeable layers and the seals.

[0064] However, the cap might equally well be moulded by injection.

[0065] In order to limit the risks of migration of oxygen towards the outside, the layer 8, 208, 308 forming seal may be made of a material absorbing oxygen. In that case, the second layer protects the first from possible alterations due to the oxygen.

Claims

1. Method for making a closure device in which a cap moulded from plastics material is equipped with a seal adapted to be arranged in abutment against the neck of a container, characterized in that it comprises steps consisting in:

positioning, in the vicinity of an inner surface (71; 271; 371) of a bottom web (7; 207; 307) of said cap (1; 201; 301), a first layer (6; 206; 306) of material impermeable to a predetermined gas or gases, and

depositing on said first layer, in place in said cap, a second layer (8; 208; 308) made of an elastic material and different from the material constituting the first layer, said second layer being intended to form said seal, by isolating said first layer from the ambient atmosphere.

2. Method according to claim 1, characterized in that it comprises a step consisting in overmoulding said second layer (8; 208; 308) on said first layer (6; 206; 306).

3. Method according to one of claims 1 or 2, characterized in that it comprises a step consisting in overmoulding, by injection or by compression, said first layer (206) against said bottom web (207).

4. Method according to one of claims 1 or 2, characterized in that it comprises a step of positioning (in 102) a plate (6) pre-cutout from a gas-impermeable material, in the vicinity of said web (7), said plate then being immobilized against said web by the deposit of said second layer (8).

5. Method according to one of claims 1 or 2, characterized in that it comprises a step of projection (F5) of said first layer (306) on said inner surface (371) of said bottom web (307).

6. Method according to one of the preceding Claims, characterized in that it comprises a prior step (in 101) of moulding said cap (1; 201; 301), the positioning of said first layer (6; 206; 306) and the deposit of said second layer (8; 208; 308) being effected continuously immediately after the moulding of said cap.

7. Closure device comprising a cap moulded by injection or compression from plastics material and equipped with a seal adapted to be arranged in abutment against the neck of a container, characterized in that it comprises a layer (6; 206; 306) of material impermeable to a predetermined gas or gases interposed between said seal (8; 208; 308) and a bottom web (7; 207; 307) of said cap (1; 201; 301), said layer being isolated from the ambient atmosphere by said cap and said seal which is made of a material different from that of the layer of material impermeable to a predetermined gas or gases.

8. Method according to one of claims 1 to 6 or device according to claim 7, characterized in that said layer (6; 206; 306) of impermeable material is a layer (63) of silica oxide, or of carbon in diamond or amorphous form, integrated in a multi-layer complex (6) disposed against said bottom web (7) and covered with a layer (8) of elastic material forming said seal.

9. Method according to one of claims 1 to 6 or device according to one of claims 7 or 8, characterized in that said layer (206; 306) of impermeable material is made of polyvinylchloride (PVC), of polyvinylidene chloride (PVDC), of ethylene vinyl alcohol (EVOH), of polyamide (PA), of polyethylene naphthalate (PEN), polyvinyl acohol (PVA), acrylate copolymer of polyacrylnitrile (PNA) type, polymethylmethacrylate (PPMA), copolymer of butadiene, styrene, bi-oriented polypropylene (BOPP) or in a mixture based on these products.

10. Method according to one of claims 1 to 6 or device according to one of claims 7 to 9, characterized in that said first layer (306) comprises a silica oxide, a varnish or a lacquer or is made by metallization.

11. Method according to one of claims 1 to 6 or device according to one of claims 7 to 10, characterized in that said seal (8; 208) is made of vinyl acetate (EVA), of elastomer, particularly a derivative of polyamide (PA), or copolymer of polyamide and/or of polyether.

12. Method according to one of claims 1 to 6 or device according to one of claims 7 to 11, characterized in that said seal (8; 208) is made of a material adapted to absorb a gas or gases, preferably a material adapted to absorb oxygen.

13. Container for liquid, particularly bottle made of plastics material, equipped with a closure device (1-8; 201-208) according to one of claims 7 to 12.