EP2731890A1

EP2731890A1 - Container with closure having an internal membrane and method for manufacturing thereof

Info

Publication number: EP2731890A1
Application number: EP12761877.5A
Authority: EP
Inventors: Dirk De Cuyper; William Dierickx
Original assignee: Resilux NV
Current assignee: Resilux NV
Priority date: 2011-07-08
Filing date: 2012-07-09
Publication date: 2014-05-21
Also published as: WO2013006927A1; BE1022366B1

Abstract

Container-closure system, particularly intended for hotfill or hot filling, and which is closable by means of a releasable closure (2, 6, 8, 11) which is provided at its top with a top surface. Wherein the closure (2, 6, 8, 11) is provided with an aperture as a pressure compensation means (3) with small dimensions, which is provided externally as a passage between the exterior of the container and the interior thereof. It is further provided with an internal vacuum limiter that is arranged in the interior of the closure in such a way that said pressure compensation means (3) is separated from the interior of the container, wherein it acts as a vacuum limiter of the interior of the container in regard of said opening (3); and method therefor.

Description

CONTAINER WITH CLOSURE HAVING AN INTERNAL MEMBRANE AND METHOD FOR MANUFACTURING THEREOF

Field of the invention

The present invention relates to a container, in particular to a hot-fill container with closure element, especially of the cap type, provided with an internal membrane.

Background of the invention

Hot-fill is an old technique, wherein the material to be bottled, such as fruit juice, is heated to 85°C and is then filled, especially into old-style traditional glass bottles. In the case of glass bottles, bottling can be carried out at up to 90°C, whereupon all micro-organisms are killed whilst the vitamins are retained.

In the case of PET, hot-fill is still widely used and, indeed, is coming increasingly back into fashion. The advantage of hot-fill is, after all, that the bottle does not have to be made aseptic, which is an expensive process. The product is heated to 85°, though, where appropriate, it is already at 75° sufficient to make the PET container aseptic. At these temperatures, most microorganisms are generally dead, already at 65°-70°. Since vitamins die only at 105°C, the vitamins, however, are retained. All of this can take place in an open space where no germ-free area is necessary. It is consequently very simple.

As far as the filling process per se is concerned, filling takes place up to a specific height of the containers, almost up to the rim, then these are closed off by means of a closure element or cap, and rotated - up to twice, even - so that the cap too should acquire these higher temperatures of the hot-fill through contact with the heated material to be bottled. After this, the containers are recooled, such as in a cooling tunnel, where they are spayed directly with water, in particular in the form of a rain of water. When this bottle is in the cooling tunnel, the fill product contained herein begins at 85° to shrink, however, including also water. As a result of this shrinkage, a vacuum is then formed in this cooling, sealed container. The vacuum formed in the container can be absorbed by means of so-called panels, which are fitted round about the container in the side wall and/or the base hereof, with a depressionnary effect which proceeds to compensate the pressure drop in the container. These panels exist in locally deformable surface parts, in particular elastic, which are formed by, for example, notches provided in the container, and which are flexible. The forces which are generated by the vacuum in the fill product space after hot-fill act upon these flexible parts, which, because of their flexibility, proceed to deform and hereupon virtually proportionately and uniformly contract and go inwards. The other, non flexible parts of the container, on the other hand, do not proceed to deform and thus keep the container uncreased from the aesthetic aspect, but also maintain its functionality by virtue of the container being kept upright. The panels thus ensure that the shrinkage can be contained in the container.

When the bottle is opened, it proceeds to slacken, whereupon the tension which until then keeps the container wall rigid is released, so that the panels revert to their original, unstressed position. Thus hot-fill packagings such as bottles or jars with sealable lid and the like need to be specially equipped, since this vacuum exerts considerable forces upon the inner walls of the container, whereby this needs to be more solidly made, such as with a special crystalline mouth in the so- called "Chinese bottle". This type of panel bottle is made so strong on its side wall that the base is forced inwards. A drawback with these containers is that they must virtually have an identical shape, and panels are not very appealing to the consumer, which thus needs to be improved, certainly from a marketing viewpoint. This then becomes a deterring criterion in the related packaging industry, which, after all, imposes high requirements in this field. Nor can these containers be profiled. The problem is consequently that the shaping of the containers is limited by the presence of the panel systems, so that containers of this type offer very little variability in shape and thus are altogether too much alike. In other words, this has the direct consequence that no customization of the container as packaging is possible.

Such panel elements or mechanisms are very effective for maintaining a balanced pressure by preventing the build-up of pressure differences and thereby maintaining the structural geometry of the container by preventing undesirable deformation hereof. Such panels are difficult to mould, however, and also have the further drawback that the labelling of the container is made difficult by the presence of a network of ribs and grooves on the surface of the container, which, as a result of its existence, appreciably limits the available surface on the container wall, which also presents a major obstacle with respect to the scope of design for the container.

In another kind of panel bottle, which can also expand/contract to compensate the shrinkage, there is another system comprising a base which can be pressed in if pressure is applied thereto. The vacuum makes the container so hard that the base, as it were, goes inwards. This base is thus impressionable and relatively displaceable with respect to the wall of the container. First a base is made, which base is very strong for the stability of the walls. If pressure is applied to it, then it can be pressed in.

The secondary problem with such containers equipped with panels is that the bottle can only be blown at specialized companies, because the wall thickness distribution in the panel systems is very important for the good functionality or working thereof. There is thus the further problem with these bottles that this becomes specialist work, in particular, in the blowing thereof, the distribution of these walls has to be consistently controlled. That process must be stable, the material dosage needs to be realized with suitable accuracy, the bottle deformation must be kept under close control. This means that the hot-fill packagings are currently very expensive.

To summarize, the deformation of the container is a consequence of the pressure difference between the atmospheric pressure which acts from outside upon the container walls as a result of the cooling-induced vacuum in the inside thereof. Thus, shortly after bottling, for example by gassing of the product or through an increased temperature of the material to be bottled, a vacuum or underpressure can be generated, after all, in the region contained between the bottling level and the closure. This tendency of the container to proceed to deform under the influence of the cooling of the warm-bottled fill material can certainly be countered by a greater wall thickness of the plastics container. However, this equally entails a higher cost attributable to the higher quantities of more widely used raw material, and the weight of the container increases accordingly. It is also known to fit in the plastics container axial stiffenings, or else so- called panels, which are placed round about the container, wherein these form hereon deformable regions which can compensate these pressure differences. These deformable regions have once again the drawback, however, that this makes it more difficult to apply identification elements, such as labels, to the container walls.

Prior art

Document US2008/0083693A1 describes a closure element of the type as described above, wherein an opening is made in an internal intermediate cap, whereby a build-up of vacuum can be prevented without having to resort to the above-described panels. Nevertheless, the herein explained closure element substantially consists of an external cap and an internal cap which is nested in the external cap or accommodated herein, the various accessories, such as membrane or opening, being connected to the internal cap or being fitted herein. This internal cap consequently acts as an extra component, which, according to this document, is necessary to be able to receive the aforementioned accessories in the closure element. The addition of this extra intermediate cap demands a perfect fitting of the inner cap into the outer cap in which it is nested, which only makes the overall production of the closure element in its entirety harder and more complex, and thus also perhaps more expensive, though this is not the intention here. Moreover, though an opening is made in this closure element with relatively complex structure, this is equally the case in the internal intermediate cap, so that there is no direct connection to the outside world, which is equally not the intention here, quite the reverse.

Document US2009/0179032 describes an analogous structure in the sense that this has a multiple cap structure with the same drawbacks as above. This closure element also has an opening which is nowhere to be found in the represented top surface of the closure element and thus equally fails to offer direct contact with the outside world. This document further describes an opening as a passage between the outside and the inside of the closure element, wherein air can freely circulate between the outside of the closure element and the inside of the flexible membrane. In the sought application of packaging for substantially dairy products, fresh fruit juices and other fresh products, this is an unauthorized freedom, however, since this can impair or affect the good preservation of the packed fill product.

Document CH699800A1 describes an analogous system, though there is also a vent opening seated in the top side of the cap. In order to enable the movement of the herein represented flexible membrane, the presence of concentric rings is required, which imposes requirements in terms of fits and tolerances and the like. This also describes in essence a deformable section, which is at the level of the cover surface of the container. Consequently the top surface of the closure element is herewith deformable, wherein this, moreover, is bonded to the container wall at the level of the pouring opening or mouth. It is also in this deformable section that a vent opening is made. Precisely owing to the fact that this section is deformable, this consequently does not absolutely ensure the good working of the opening in view of the fact that this opening must be kept small, especially where the container is intended to receive dairy products or fresh fruit juice herein.

This document further describes a closure element not only with small opening diameter, but also with larger opening diameters, virtually without discrimination. The herein quoted larger orders of magnitude harbour a risk that, as a result of a possibly over-large diameter or section, this can affect the content of the container, especially where it is a matter of dairy products, or else fresh fruit juice and other fresh products which ideally have as limited a contact as possible with or are as little exposed as possible to the outside air. This virtually arbitrarily presented choice between smaller and larger opening diameters is also the reason for stipulating that they do not destroy the required rigidity of the deformable section in which the opening is made.

Aim of the invention

The object of this invention consists in eliminating the above-described drawbacks of the prior art and in providing a container with closure element with which a satisfactory solution to the aforementioned problems in terms of vacuum build-up is provided, especially in hot-fill bottling. It is herewith endeavoured, on the one hand, to provide a closure element for a plastics container which can be easily produced and at reasonable cost, which closure element at the same time also effects a satisfactory compensation of the pressure differences resulting from warm bottling, and, on the other hand, to counter vacuum which is generated after cooling of the warm-bottled containers. In this context, it is also the intention to ensure the required sealing of the closure element, and visible signs of the aforementioned vacuum formation, such as the inadmissible deformation of the container hereby, must also be eliminated.

Summary of the invention

To this end, a container with closure element of the aforementioned type is proposed according to the invention, as defined in the main claim.

It was endeavoured to make the bottle in standard construction, by implication by deliberately forgoing a panel system in the bottle itself, so that recourse was made to another component of the bottle-closure element system and was thus sought in the releasable lid-screw cap or cap.

Thanks to the measures represented above, a solution is thus offered by virtue of the invention which is not described by the aforementioned prior art, nor even suggested by it, neither individually, nor in mutual combination, more particularly the adoption of a barrier in the cap, and preferentially in the aforementioned membrane. The latter may be important indeed, because the presence of an opening in the cap reduces the effectiveness of the gas barrier. In order to be able to trap this gas, the flexible membrane shall ideally be produced from a material having an extremely high gas barrier.

The sealable lid-screw cap can assume various forms, but all are provided with an air hole in the external surface hereof.

Between the bottle and the sealable lid-screw cap, there is placed a membrane, by which a seal is obtained as a result of the acquired tension from screwing of the lid onto the bottle.

The membranes deform through the action of the vacuum forces and revert after the opening of the packaging back into their original state or not, according to their elastic or dynamic deformability.

According to an advantageous embodiment of the invention, a membrane, which is produced from a flexible material, preferably having a high barrier characteristic, more preferably also having a memory, is provided. The forces generated in the fill product chamber after hot-fill suck the membrane downwards into a deformed state. In order to allow the membrane to move freely in the cap, this small hole is provided in the sealable lid-screw cap.

According to the present invention, the said opening has, by contrast, a diameter which is as small as possible, to be precise such that this is just sufficient to be in limited contact with the outside of the container - normally at atmospheric pressure -, in order herewith to be able to make the necessary contribution to the prevention of the aforementioned pressure build-up with compensation hereof, without however forming an inadmissible entry port for the penetration of external air in order hereby as far as possible to prevent possible oxidation of the content. In other words, the opening is dimensioned such that it acts as a virtually unidirectional valve, which triggers degassing of the fill product in the inside and which only makes a flow possible under pressure -e.g. induced by the aforementioned vacuum formation- and not without the presence of a stimulating pressure which creates this flow. In particular, a mere atmospheric pressure is thus not sufficient to be able to produce such a flow in such a micro-opening.

In a preferred embodiment of the invention, the container has a cylindrical section, particularly being virtually smooth, and/or having more particularly graphic markings on its shell surface, in particular an identification means such as a brand name, logo, and the like of the contained fill product, which is virtually only possible thanks to the absence of panels in the shell surface which is made possible owing to this invention.

According to a further embodiment of the invention, the membrane is a separate injection moulding part made of a flexible material such as PP, PE or TPE having a very thin wall thickness, where appropriate provided with panel systems or hinged surface parts in the material of the container at localized sites thereof, in order to enable the expansion/contraction oscillation. A membrane can deform under the action of the vacuum forces, into a deflected position with respect to the rest state.

According to a still further embodiment of the invention, the membrane consists of an inner ring, also as a seal between bottle and sealable lid-screw cap and a plunger. After the hot-fill operation, the inner ring and the plunger are mounted in the represented state, but under action from the vacuum forces after hot-fill, the plunger moves downwards into the working position.

According to yet another embodiment of the invention, the membrane consists of a flexible material with PP, PE, TPE which is formed by thermoforming of a foil, wherein the cup can deform through the action of the vacuum forces.

In a particular embodiment, the plastics container is a jar, more specifically having an opening of at least 50 mm.

Further particularities and characteristics are defined in further sub-claims.

Further details are explained in greater detail below in some illustrative embodiments of the invention, with reference to the appended drawings. In these, the same reference symbols relate to the same or analogous elements. Brief description of the drawings

Figures 1 to 4 each represent an embodiment of a sealed container according to the invention with variants, viewed in perspective view, according to a general representation.

Figures 5 to 8 represent the embodiments represented in the previous figures, yet viewed in respective side views, on a reduced scale.

Figures 9 to 12 represent the embodiments represented in the previous figures, yet viewed in cross section along the line A-A, on a reduced scale.

Figures 13 to 16 represent the embodiments represented in previous figures 1 to 4, yet viewed in cross section along the line A-A, according to a detailed view hereof in enlarged section of the respective top parts.

Fig. 17 is a detailed representation of the sectional representation represented in Fig. 14, in an enlarged view of a first embodiment of a closure element fastened to the container according to Fig. 3.

Fig. 18 is a detailed representation of the sectional representation represented in Fig. 14 in an enlarged view of a first embodiment of a closure element fastened to the container according to Fig. 4.

Fig. 19 is a detailed representation of the sectional representation represented by Fig. 15 in an enlarged view of a first embodiment of a closure element fastened to the container according to Fig. 2.

Fig. 20 is a detailed representation of the sectional representation represented in the previous Fig. 16 in an enlarged view of a first embodiment of a closure element fastened to the container according to Fig. 1.

Description

In general terms, the present invention relates to containers which are sealed by means of a detachable closure element provided with at least 1 opening of small dimension. This is further provided with a vacuum delimiter, in particular a membrane, advantageously elastic, which is fitted in the inside of the closure element in such a way that the aforementioned opening is and remains isolated from the inside of the container. This deformable membrane acts as a vacuum delimiter of the inside of the container from the aforementioned opening, wherein the aforementioned membrane is elastically deformable between a rest state and an operating state et al. In warm bottling, a vacuum is generated in the sealed bottling space, following sealing of the packaging after hot-fill, through the cooling of the fill product with resultant shrinkage hereof. Figs.1 to 12 show a standardly constructed bottle, that is without panels herein, neither in the walls hereof, nor in the base. A panel system is, however, provided in the sealable lid-screw cap.

This sealable lid-screw cap can assume different forms 2, 6, 8, 11 , whilst they are respectively provided with an air hole 3.

Between the bottle and the sealable lid-screw cap is placed a membrane 4, 7, 9, 12. Through the acquired tension from the screwing of the lid 2, 6, 8, 11 onto the bottle 1 , a seal 13 is obtained, which seal is represented in Fig. 18.

The inlays or membranes deform through the action of the vacuum forces and, after the packaging has been opened, revert to their original state, depending on their deformability, elastic or plastic.

An inlay 4 is produced from a flexible material, particularly advantageously with a high barrier characteristic and with a memory. The forces generated in a fill product chamber 5 after hot-fill suck the inlay downwards into a state 4'. In order to allow the inlay to move freely, a small hole 3 should be provided in the sealable lid-screw cap.

A construction variant of the inlay 7 consists of a separate injection moulding part made of a flexible material such as, for example, PP, PE, TP having a very thin wall thickness. These can be provided with panel systems or hinges in order to be able to effect the expansion/contraction as a pressure difference compensating element. The membrane 7 can deform, under the action of the vacuum forces, into position 7'.

A further construction variant of the inlay according to Fig. consists of an inner ring 9, also acting as a seal between the bottle 1 and the sealable lid-screw cap 8, and a plunger 10. Following hot-fill, 9 and 10 are mounted in the illustrated state, but when acted upon by the vacuum forces after the hot-fill, the plunger 10 moves downwards into position 10'.

An inlay according to 12 consists of a flexible material, such as, for example, PP, PE, TPE, which is formed by, for example, thermoforming of a foil, wherein, through the action of the vacuum forces, the cup can deform into 12'.

According to the invention, the deformable section, however, is formed by the flexible membrane which is disposed between the aforementioned top surface of the closure element and the inside of the container, more specifically the fill level herein, as represented in the figures.

In addition, the flexible foil is connected at its margin to the inner edge of the neck of the container, in particular welded hereto.

The nomenclature table below represents a summary of the various construction variants: Bottle - jar

Lid - screw cap embodiment 1

Air hole

Membrane-inlay embodiment 1 Membrane-inlay embodiment 1 when chamber

5 under vacuum after hot-fill or warm bottling

Fill product chamber

Lid - screw cap embodiment 2

Membrane-inlay embodiment 2 Membrane-inlay embodiment 2 when chamber

5 under vacuum after hot-fill

Lid - screw cap embodiment 3

Inner ring

Movable plunger Movable plunger when chamber 5 under vacuum after hot-fill

Lid - screw cap embodiment 4

Membrane-inlay embodiment 4 Membrane-inlay embodiment 4 when chamber

5 under vacuum after hot-fill

Inlays 4, 7, 9 and 12 serve as a seal

between lid-screw cap and bottle

Claims

1. Container-closure system, particularly intended for hotfill, which is closable by means of a releasable closure (2, 6, 8, 11) which is provided at its top with a top surface (29), characterized in that the closure (2, 6, 8, 11 ) is provided with at least one opening as a pressure compensation means (3) with small dimensions, which is provided externally as a passage between the exterior (28) of the container and the interior (27) thereof, which is further provided with an internal vacuum limiter that is arranged in the interior of the closure in such a way that said pressure compensation means (3) is separated from the interior of the container, wherein it acts as vacuum limiter of the interior of the container in regard of said opening (3).

2. Container-closure system according to the preceding claim, characterized in that said vacuum limiter comprises an elastic membrane, wherein said membrane (7, 12) is deformable between a rest state (A) and an operational state (B).

3. Container-closure system according to any one of the preceding claims, characterized in that said vacuum limiter is elastically deformable between a rest state (A) and an operational state (B).

4. Container-closure system according to any one of claims 1 or 2, characterized in that said vacuum limiter is plastically deformable.

5. Container-closure system according to any one of the preceding claims, characterized in that the vacuum limiter is formed by a flexible film, in particular disc-shaped, more particularly with a surface profile that is curved to the interior of the container and that is virtually continuous.

6. Container-closure system according to any one of the preceding claims, characterized in that said vacuum limiter (3) is provided with a barrier layer.

7. Container-closure system according to any one of the preceding claims, in particular the previous one, characterized in that said closure (2, 6, 8, 11) is provided with a barrier layer.

8. Container-closure system according to one of the two preceding claims, characterized in that said vacuum limiter (7, 12), resp. closure is/are composed of a material having a pronounced high barrier characteristic, in particular with a memory.

9. Container-closure system according to any one of the preceding claims, characterized in that said vacuum limiter constitutes a separate injection molded part, in particular with a very thin thickness.

10. Container-closure system according to any one of the preceding claims, characterized in that said vacuum limiter has a thickness comprised between 0,1 and 2 mm.

1 1. Container-closure system according to any one of the preceding claims, in particular the previous one, characterized in that said vacuum limiter (3) has a multilayer structure.

12. Container-closure system according to any one of the preceding claims, in particular the previous one, characterized in that said vacuum limiter is mounted on the closure (2, 6, 8, 11 ), in particular in a peripheral manner therein, more particularly directly attached to a circular circumference of the cap itself, even more particularly welded thereto.

13. Container-closure system according to any one of the preceding claims, characterized in that said vacuum limiter is composed of a flexible material, and/or esp PP, PE or TPE material.

14. Container-closure system according to one of both preceding claims, characterized in that said membrane (7, 12) is composed of a material which is formed by thermoforming of a foil, wherein the closure can deform by the action of the vacuum forces.

15. Container-closure system according to any one of the preceding claims, characterized in that said vacuum limiter has a substantially monotonous profile, in particular smooth and without discontinuities.

16. Container-closure system according to any one of the preceding claims, characterized in that said vacuum limiter is provided with panels in order to allow the oscillation of the system.

17. Container-closure system according to any of the preceding claims, characterized in that the aforementioned vacuum limiter, in particular membrane, consists of an inner ring, further acting as a seal between the bottle and lockable lid-screw cap, and a plunger.

18. Container-closure system according to any one of the preceding claims, characterized in that said pressure compensation means (3) is formed by an opening (3') as ventilation means, which is provided in the lid plate forming top portion of the closure.

19. Container-closure system according to the preceding claim, characterized in that said opening consists in a bore (3') in the closure, in particular wherein the top surface thereof is rigid.

20. Container-closure system according to any one of both preceding claims, characterized in that said opening (3') has a substantially cylindrical profile, in particular with a substantially circular section, which is substantially axial in regard of the axis (I).

21. Container-closure system according to any one of the preceding claims 18 to 20, characterized in that said opening (3') has a pronounced small section, in particular barely visible, possibly not too visible with naked eye, notably which is just sufficient to counter both the building up of a pressure difference into the interior of the container and a gas penetration from the exterior to the interior of the container.

22. Container-closure system according to the preceding claim, characterized in that said opening (3') is sized such that it acts as a one-way closure which allows the gas passage through it, only under the action of a pressure differential that differs from the atmospheric pressure.

23. Container-closure system according to any one of the preceding claims 18 to 22, characterized in that said opening (3') opposite to the axis (?) is shifted over a certain distance, in particular decentered with respect thereto.

24. Container-closure system according to any one of the preceding claims, characterized in that said closure is virtually made of one piece.

25. Container-closure system according to any of the preceding claims 18 to 24, characterized in that said opening (3') is provided laterally in the surrounding edge of the closure.

26. Method for producing a container-closure system, in particular as defined according to any one of the preceding claims, according to the so-called hotfill method, characterized in that an inner and elastic diaphragm is arranged releasably in the interior of the closure (2, 6, 8, 11) with which the container is closed, wherein said membrane (7, 12) on the closure (2, 6, 8, 11 ) is mounted in a peripheral manner therein, in that at least one opening (3) with small dimensions is made in the closure, in such a way that said opening (3) is isolated from the interior of the container, and hereby serves as vacuum limiter of the interior of the container in front of the said opening (3), wherein said membrane is inserted between the container and the lockable lid-screw cap, wherein a seal is obtained by the tension resulting from screwing the lid on the bottle, wherein said membrane (7, 12) elastically deforms between an inactive rest position (A) and an operational deflected state (B).

27. Method according to the preceding claim, characterized in that the membrane is deformed by the action of the vacuum forces, and reverts to their original state dependent upon return their deformability, after the package is opened.

28. Method according to one of both preceding claims, characterized in that, after the hotfill operation, the inner ring and the plunger are mounted, wherein the plunger moves downwards to an operating position when the vacuum forces act after hotfill.

29. Closure for use in a system as defined in one of the preceding claims 1 to 25, possibly manufactured as defined according to one of the preceding method claims 26 to 28.

30. Container provided with a closure as defined in the preceding claim, esp wherein the shell surface thereof is substantially cylindrical with a virtually circular section, in particular which is virtually smooth, and/or having more particularly graphical indications at its shell surface, still more particularly identification means such as a brand name, logo, etc., with absence of panels in the shell surface.

31. Container according to the preceding claim, wherein it is formed by a bottle, in particular of plastic material.

32. Container according to the preceding claim, wherein it is formed by a jar, in particular with a greater cross sectional dimension and/or made from plastic material, more particularly provided with peripheral panels for supporting the pressure compensation effect.

33. Use of a system according to any one of the claims 1 to 25, in particular from 2, wherein said container is formed by a bottle, possibly a jar, particularly a plastic container, more particularly of PET, preferably with a barrier layer therein.

34. Use of a system according to the previous claim, in particular when dependent from 2 to 18, wherein said closure is formed by a cap, in particular made of plastic, more particularly of PET, possibly wherein said container and closure are composed of virtually the same material, preferably with a barrier layer therein, still preferably in the isolation membrane.