Abstract:
A beverage container for the storage of a carbonated drink comprising a container body ( 10 ) including an opening ( 11 ) and removable closure means ( 12 ) for closing the opening ( 11 ), the closure means comprising a foil ( 20 ) which provides a gas tight seal for the opening ( 11 ). The arrangement may be such that a tendency of forces acting on the foil ( 20 ) due to pressure within the container to separate the foil ( 20 ) from the container body ( 10 ) by peeling away therefrom is reduced e.g. by the provision of a collar ( 12 A) to limit deflection of the foil ( 20 ) adjacent the bond therebetween and/or by the shape of the rim ( 15 ) of the container body ( 10 ), so the closure is capable of withstanding higher internal pressures than would otherwise be the case.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to beverage containers, and particularly relates to containers for supplying beverages to consumers. The invention has particular utility for the storage and supply of carbonated and other sparkling drinks, but may also be used with other types of drinks. 
       BACKGROUND ART 
       [0002]    For many years there has been a desire among drinks suppliers and container manufacturers to provide practical wide-mouth beverage supply containers which consumers may drink from comfortably in the same manner as from a drinks glass or other drinking vessel, particularly in relation to carbonated drinks such as beers, etc. Despite the tremendous advantages that such a beverage container would provide for drinks suppliers, container manufacturers and consumers alike, no successful beverage container that fulfils these aims has yet been produced. Consequently, bottles and ring-pull cans currently remain the main practical beverage supply containers for consumers. This is because there are significant technical problems associated with wide-mouth containers to overcome, and no practical solution to the problems has successfully been devised. The present invention aims to provide a practical beverage container, which may be a wide-mouth container (although the invention is also applicable to other types of beverage container). 
         [0003]    The present invention seeks to provide a beverage container with closure means capable of with-standing increased pressure within the container, e.g. due to the storage of carbonated or other gas containing liquids and/or elevated temperatures and/or shock loads. 
       SUMMARY OF THE INVENTION 
       [0004]    A first aspect of the invention provides a beverage container for the storage of a carbonated drink comprising a container body including an opening and removable closure means for closing said opening, the closure means comprising a foil which provides a gas tight seal for said opening. 
         [0005]    A second aspect of the invention provides a beverage container comprising a container body including an opening and removable closure means for closing said opening, the closure means comprising a foil which seals said opening, the arrangement being such that a tendency of forces acting on the foil as a result of pressure within the container to separate the foil from the container by peeling away therefrom is reduced or inhibited whereby the closure is capable of withstanding higher internal pressures than would otherwise be the case. 
         [0006]    In some embodiments, the closure means comprises a removable holding component or cap for fitting over the foil. 
         [0007]    If a cap is used, this preferably provides physical support for the foil, e.g. by limiting the extent to which it can be distorted by pressure increases within the container and/or by reinforcing the connection between the foil and the container. The cap may be generally circular so it lies over the perimeter of the foil around the periphery of the opening and thus assists in holding the foil in contact with the container. In some cases this may also provide sufficient obstruction to limit bowing out of the foil due to internal pressure but, preferably, the cap extends across the entire foil both to provide further obstruction to deflection of the foil, particularly at the centre thereof, but also to protect the foil against damage from physical contact with external objects which might puncture the foil and/or reduce its integrity. The cap thus strengthens and/or protects the connection of the foil with the container and provides puncture protection for the foil. 
         [0008]    Preferably, the container has a lip around the opening to which the foil is bonded, the lip being shaped such that forces arising in the foil due to pressure within the container apply predominantly shear forces (rather than peel forces) to the bond between the foil and the lip. 
         [0009]    The lip may be shaped so as to have a substantially flat area, extending around the opening which is inclined outwardly relative to the axis of the opening, the foil being bonded to said substantially flat area. 
         [0010]    In a preferred arrangement, the normal to the said substantially flat area lies at an angle α to the axis of the opening, the angle a being selected in relation to the radius (R) of the opening and a maximum deflection (D) of the foil due to pressure within the container such that when the foil is subject to the maximum deflection, forces acting on the foil where it is bonded to said substantially flat surface are substantially parallel to said surface so as to apply substantially only shear forces to the bond therebetween. 
         [0011]    The cap may be made from a range of materials but is preferably formed from a plastics material such as polypropylene (PP) or polyethylene (PE) and may be formed by injection moulding. The cap is preferably releasably secured to the container, by a snap-fit and/or by other securement means which securely hold it on the container. Means may be provided to release the cap, e.g. to make it easier to remove from the container. Venting means are also preferably provided to allow pressure within the container to be vented prior to complete removal of the cap and/or the foil. If the foil is attached to the container controlled venting may be provided as the foil is peeled off the container. 
         [0012]    The foil may also be attached to the container around a perimeter of the opening by induction heating. Preferably, the attachment to the container, whilst being strong enough to withstand the desired level of pressure within the container, is weaker than the attachment to the cap so that upon removal of the cap, the foil is separated from the container but remains attached to and is removed with the cap. 
         [0013]    In another arrangement, the foil may not be attached to the container but seals the opening thereof by simply being held in contact with or pressed onto the container by the cap. 
         [0014]    References to foil herein include impervious laminates comprising one or more layers which give the foil strength and one or more layers for attaching the upper and/or lower surface of the foil to another article. Such foils are widely used in other fields. Where the foil is to be secured by induction heating, an electrically conductive layer is required. This is usually a metallic layer and most commonly a layer of aluminium. The electrically conductive layer is typically provided with one or more plastic coatings, e.g. of polyethylene, which melt when the electrically conductive layer is heated to bond the foil to an article held in contact therewith. Such foils can be bonded to both glass and plastic articles. 
         [0015]    The foil is preferably secured to the container in a manner capable of withstanding elevated internal pressures, e.g. of 1-2 bar (as might arise if a carbonated drinks container is subject to high temperatures). As well as preventing the egress of gas, the foil also protects the container from ingress of gas, so helps prevent contamination of the beverage and prevent it becoming stale. With such a foil, the beverage container can have a shelf-life of at least 9 months (as typically required for beers and other carbonated drinks sold in containers). 
         [0016]    The foil may also provide tamper evidence in that if the foil is intact it provides the consumer with reassurance that the product has not been tampered with or previously opened or otherwise exposed to the external atmosphere. This function is further enhanced if the cap is formed of a transparent material. 
         [0017]    Although the foil is preferably secured to a lip of the container around the mouth thereof, it may also be recessed within the container and secured to an inner surface thereof, e.g. at a position spaced from the mouth of the container, for example 5-10 mm below the lip of the container. This may be appropriate when the cap fits within the container and the foil is provided at the lower end thereof. If the container is not filled with beverage up to the lip, it also enables the foil to be positioned nearer the surface of the beverage so as to reduce the space left above the beverage. Removal of a foil recessed within the container may also be less prone to causing spillage as the surface of the beverage is at a lower level in the container and the container can be grasped at the level of the foil, or above this level, so enabling the foil to be peeled off in a more controlled manner. 
         [0018]    The container is typically formed of a plastics material, e.g. polyethylene terephthalate (PET), or of glass. The container may be shaped to resemble a conventional drinking vessel, e.g. a beer glass, shaped in the form of a bottle or of some other shape. 
         [0019]    The opening of the container body preferably is a wide-mouth opening. By a “wide-mouth opening” is meant (at least in its broadest sense) an opening of a size suitable for a person to drink from the container in the same manner as from a drinks glass or similar drinking vessel. That is, in its broadest sense, the wide-mouth opening of the container (for embodiments of the invention having a wide-mouth opening) generally renders the container suitable as a drinking vessel from which a beverage supplied in the container may be conveniently drunk (in contrast to conventional narrow-necked bottles and ring-pull cans which generally are not regarded as comfortable drinking vessels). In practice, this requirement means that the diameter of the wide-mouth opening of the container will normally need to be at least 40 mm, preferably at least 45 mm, and more preferably at least 50 mm. Additionally, an excessively wide opening is generally difficult for the consumer to drink from, and thus the wide-mouth opening preferably has a diameter no greater than 150 mm, more preferably no greater than 100 mm, and especially no greater than 80 mm. A particularly preferred diameter range for the wide-mouth opening is 50 to 80 mm, and examples of particular preferred diameters included 53 mm and 63 mm. 
         [0020]    The container may also have a narrow-mouth opening, e.g. a bottle-type opening. Such an opening may for example, have a diameter of 40 mm or less. Conventional standard bottle mouth sizes include diameters of 28 mm and 38 mm and the opening may be of this size. 
         [0021]    The container body preferably has no thread or thread segments on its exterior. Consequently, the container body preferably is comfortable for a consumer to drink directly from the container body. 
         [0022]    As indicated at the beginning of this specification, although the containers described herein may be used for other types of beverages, the invention is particularly suited to the storage and supply of carbonated and other sparkling drinks, for example beers, ciders, sparkling wines (including champagne), other fizzy alcoholic beverages, and non-alcoholic fizzy and sparkling beverages, including sparkling water and carbonated soft drinks or the storage of any other liquid capable of generating an elevation pressure within the container. 
         [0023]    Other preferred and optional features will be apparent from the following description and from the subsidiary claims of the specification. 
         [0024]    The invention also relates to the use of a beverage container of the type described for containing a carbonated beverage and to a method of sealing such a container. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0025]    The invention will now be further described, merely by way of example, with reference to the accompanying drawings, in which: 
           [0026]      FIG. 1  shows a partial, exploded view of a first embodiment of a beverage container according to the present invention; 
           [0027]      FIGS. 2A ,  2 B and  2 C show similar views to  FIG. 1  of the container with part-sectional views of the closure means prior to assembly, in a sealed configuration and in a venting configuration, respectively; 
           [0028]      FIG. 3  is a perspective view of two of the beverage containers shown in  FIG. 1 , one with closure means in place and the other with the closure means removed; 
           [0029]      FIG. 4  is a perspective view of a second embodiment of a beverage container according to the invention; 
           [0030]      FIG. 5  is a cross-sectional view of the container shown in  FIG. 4 ; 
           [0031]      FIG. 6  is a sectional view of a third embodiment of a beverage container according to the invention showing a cap ready to be connected with a container; 
           [0032]      FIG. 7  is a corresponding view showing the cap when connected with the container. 
           [0033]      FIG. 8A  shows an exploded, perspective view of a fourth embodiment of a beverage container according to the invention; 
           [0034]      FIG. 8B  is a vertical, sectional view through part of the beverage container of  FIG. 8A  when assembled; 
           [0035]      FIG. 9A  is an exploded perspective view of a collar used in a fifth embodiment of the invention and  FIGS. 9B and 9C  illustrate the function of this collar; and 
           [0036]      FIGS. 10A and 10B  are schematic, sectional views of further embodiments of the invention illustrating a further way of reducing peel forces. 
       
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0037]    As indicated above, whilst a foil may be used on its own to seal a wide-mouth container it is preferably used in conjunction with closure means or a cap which protects and/or re-inforces the foil. Many different kinds of cap may be used and these may be secured to the container in different ways.  FIGS. 1-3  illustrate a first form of cap that may be used,  FIGS. 4-5  illustrate a second form of cap,  FIGS. 6-7  illustrate a third form of cap,  FIG. 8  illustrates a fourth form of cap and  FIGS. 9-10  illustrate a fifth form of cap. 
         [0038]    In the embodiment shown in  FIGS. 1-3 , foil  20  is shown in  FIG. 2A  but is omitted from the other figures for clarity. 
         [0039]      FIG. 1  shows the upper part of a beverage container (the whole container is shown in  FIG. 3 ) comprising a container body  10  with a wide-mouth opening  11  at its upper end and closure means in the form of a lid  12  comprising a first part  12 A for securing to the body  10  and a second part  12 B adapted to be connected to the first part  12 A. 
         [0040]    In the embodiment shown, the first part  12 A comprises a disc-shaped upper part  13  with a skirt  14  depending from the periphery thereof. The body  10  has a radially projecting rim  15  adjacent the wide-mouth opening  11  and the skirt  14  has an internal diameter such that it can be pressed down over the projecting rim  15 . The radially outer surface of the skirt  14  is provided with a screw thread  16  and the second part  12 B of the cap comprises an annular member with a screw thread  17  on its internal surface for engaging with the screw thread  16  of the first part  12 A. The outer surface of the second part  12 B is formed, e.g. with ribs  17 A and grooves  17 B, so as to facilitate the application of torque thereto by a user&#39;s hand to rotate the second part  12 B relative to the first part  12 A when threadably engaged therewith. The second part  12 B is optionally provided with a disk-shaped member  18 , e.g. to carry promotional material such as a trade mark used in relation to the beverage contained within the container  10 . Alternatively, this may be provided on the upper surface of the upper part  13  of the first part  12 A of the cap. 
         [0041]    The free end of the skirt  12 A is provide with an inclined flange  18  the function of which will be described below. 
         [0042]    The skirt  14  and radial projection  15  are shaped so that the first part  12 A of the cap is a loose snap-fit onto the container, i.e. sufficient to retain the first part thereon but removeable upon application of a manual pulling force. In use, the second part  12 B of the cap would typically be connected to the first part  12 A by engaging the respective threads thereof in a first configuration. The cap comprising first and second parts  12 A and  12 B is then pressed onto the container so that the first part snaps over the radial projection  15  and engages an underside thereof. The skirt  14  and the underside of the radial projection  15  are preferably also provided with mutually engageably components  19 A,  19 B to limit rotational movement therebetween. 
         [0043]    The second part  12 B is then screwed further onto the first part  12 A to a second configuration in which it biases the inclined flange  18  inwards. This secures the first part  12 A more tightly under the radial projection  15  and creates a downward tension in the skirt  14  so the inner surface of the skirt  14  and/or the underside of upper part  13  of the first part  12 A of the cap is pressed against the container  10 . A foil  20  (see  FIG. 2A ) is provided between the inner surface of the first part  12 A and the container  10  so as to cover the wide mouth opening  11 . 
         [0044]    The foil  20  preferably comprises an aluminium layer with a polymer layer on one or both faces thereof. The foil  20  may be welded, e.g. by induction heating, to the container  10  and/or to the first part  12 A. Preferably, the foil is arranged to remain attached to the first part  12 A and be removed therewith when the container is opened.  FIG. 2B  shows the cap with the first and second parts  12 A and  12 B in the second configuration, i.e. in which the second part holds the first part in a secured relationship with the container  10  as described above. 
         [0045]    When it is desired to open the container, the second part  12 B is partially unscrewed from the first part  12 A so it is moved out of said second configuration. The second part  12 B is thus no longer held in secure engagement with the container, so pressurised gas within the container can be vented between the container  10  and the foil  20  (when the foil  20  is not welded to the container but is just used as a sealing gasket). The first part  12 A of the cap is, however, prevented from being blown off the container  10  due to engagement of its skirt  14  under the projection  15 . In some cases, this may be a relatively loose engagement, e.g. as formed when the cap is first snapped onto the body  10  as described above, or the second part  12 B may still be in a position relative to the first part  12 A in which it deflects the flange  18  inwards to tighten the engagement of the skirt  14  under the projection  15 . 
         [0046]    The second part  12 B is also prevented from blowing off by means of its screw threaded engagement with the first part and/or engagement of hook-like projections  17 C at a bottom edge thereof with a lower part of the skirt  14  or flange  18 . 
         [0047]    After such venting has taken place, the cap (with the first and second parts  12 A,  12 B connected together) can be manually pulled off the container  10  by overcoming the loose snap-fit between the first part  12 A and the projection  15 . If necessary, the second part  12 B may be unscrewed further to loosen this engagement prior to pulling the cap off the container. 
         [0048]    The second part  12 B could, if desired, be unscrewed completely and detached from the first part  12 A prior to pulling off the first part  12 B but, preferably, they are designed to be pulled off together whilst they are still connected to each other. Indeed, the second part  12 B may be designed such that, once connected to the first part  12 A, it cannot be detached therefrom, e.g. by means of a ratchet associated with the screw thread attachment therebetween. 
         [0049]    In a preferred arrangement, the foil  20  is welded to the container body  10  so as to seal the mouth thereof. In this case, venting occurs when the foil starts to be removed or peeled from the container. Depending on the design, this may occur when the engagement of the first part  12 A is loosened and/or when the cap is removed. The foil  20  is preferably also welded to the cap, e.g. to the underside of the first part  12 A, so that it is removed from the container when the cap is removed therefrom. The welded connection between the foil  20  and the first part  12 A is thus preferably stronger than the welded connection between the foil  20  and the container  10 . 
         [0050]    The foil  20  is preferably circular so as to cover the wide mouth  11 . If desired, it may also extend over the exterior of the rim  15 . If the foil is secured to the first part  12 A, the foil may be of annular shape, e.g. with its outer perimeter secured to the container and its inner perimeter secured to the underside of the first part  12 A, or with its underside secured to the container and its upperside secured to the underside of the first part  12 A. 
         [0051]    The second embodiment shown in  FIGS. 4 and 5 , comprises a container body  21 , a foil  22  covering the mouth of the container body  21  and a cap  23  fitted onto the container body  21  over the foil  22 . 
         [0052]    The container body has a lip  24  and the foil  22  extends over the lip  24 . The cap is preferably a snap-fit plastic cap but a metal cap may also be used which can be crimped over the lip  24 . 
         [0053]    The cap  23  is shaped so as to be a snap-fit over the lip  24  of the container body  21 . Alternatively, the cap  23  may be shrunk fit onto the container body  21 . The foil  22  is preferably secured to the lip  24  by localised induction heating to melt a plastic layer on the underside of the foil and so weld it to the lip  24 . Alternatively, or additionally, the foil  22  is crimped over the edge of the lip  24 . If required, it may also be sealed to the external surface of the container. The foil is also preferably secured to the cap  23  by localised heating to melt a plastic layer on the upperside of the foil and so weld it to the underside of the cap  23 . 
         [0054]    In the illustrated embodiment, the cap  23  is provided with a tab  25  to assist in removing the cap. As shown in  FIG. 2 , the tab is connected to the perimeter of the cap and weakened portions  26 A,  26 B are provided on each side thereof to provide break lines which tear as the tab  25  is lifted. The foil  22  is preferably connected to the underside of the tab  25  so the foil is also lifted with the tab  25 . 
         [0055]    Further weakened areas  27 A,  27 B in the shape of a V may also be provided in the cap so that lifting the tab  25  pivots a pointed section  23 A of the cap into the container so as to pierce the foil  22  and so vent the container. It will be appreciated that this is similar to the action of a conventional ring-pull provided on an aluminium can. Once the container has been vented, the tab  25  is used to peel the remainder of the cap  23  and foil  22  off the container. 
         [0056]    The weakened portion  26 A,  26 B,  27 A,  27 B may comprise reduced thickness areas of the cap  23 , e.g. formed by grooves cut or moulded into the upper and/or lower surface of the cap  23 . 
         [0057]    The illustrated tab  25  is relatively narrow but other forms of tab may be provided, e.g. a wider tab extending across a greater part of the width of the cap. The weakened portions  26 A,  26 B may, for example, be spaced part by a greater distance, for instance by a distance greater than half the diameter of the cap  23 . 
         [0058]    The beverage container shown in  FIGS. 6 and 7  comprises a container  30  with an internal screw thread  30 A and a one-piece cap  32  having a screw thread  32 A on the external surface of a bore seal  33  which depends from an upper part  34 . The upper part  34  of the cap extends over a lip  30 B of the container and has a tamper-evident collar  35  which engages under said lip  30 B. 
         [0059]    A foil  36  is provided where the lower edge of the bore seal  33  engages with a sealing ring  37  on the internal wall of the container  30 . The foil  36  may be bonded to the lower edge of the bore seal  33  and/or to the sealing ring  37 . This may be done when the foil is in situ but it may also be pre-bonded to either component prior to the cap being connected to the container. 
         [0060]    The cap  32  is connected to the container by means of the screw threads  32 A and  30 A. Projections  32 B and  30 C are also provided on the cap and container respectively to act as stops which inhibit accidental unscrewing of the cap  32  until a predetermined torque is applied thereto. As the cap is screwed on, the tamper evident band snaps over the container lip  30 B. 
         [0061]    To open the container, the cap  32  is unscrewed causing the tamper evident band  35  to separate from the cap  32 . The foil  36  is also lifted as the cap moves upwards so it unpeels from the sealing ring  37 . The cap  32  may move to a venting position determined by the form of the screw threads  32 A and  30 A and/or the peeling of the foil  36  may provide controlled venting so that missiling of the cap is  32  prevented. Preferably the foil remains attached to the bore seal  33  so it is removed with the cap  32 . 
         [0062]      FIG. 8  shows a fourth embodiment of the invention in which a foil is used to seal a wide-mouth container in conjunction with closure means or a cap which protects and/or re-enforces the foil. 
         [0063]      FIG. 8A  shows a container  110  with an opening  111  and closure means comprising a foil  112 , cap  113  and collar  114 . 
         [0064]    The container is shaped to resemble a beer glass and has a lip  110 A around its opening  111 . The foil has a top part  112 A and skirt  112 B. The cap  113  includes one or more gaps  113 A in its periphery, has thread-like formations  113 B on its external surface and preferably has tamper evident clips  113 C attached thereto by a living hinge and carrying a projection. The collar  114  comprises threadlike formations  114 B on its inner surface for engaging with the thread-like formations  113 B of the cap and a recess and hole  114 C for receiving each clip and projection  113 C. 
         [0065]    As shown in  FIG. 8B , the foil  112  is held in contact with the lip  110 A by the cap  113 . The cap  113  has an internal projecting flange  113 D which snap-fits beneath the lip  110 A and the collar  114  secures the cap  113  to the container  110  by surrounding it so as to prevent the flange  113 D disengaging from the lip  110 A. The collar  114  is secured to the cap  113  by the respective thread-like formations  113 B,  114 B thereof. 
         [0066]    To remove the closure means, the collar  114  is ‘unscrewed’ from the cap  113  and removed. The cap  113  can then be prised off the container  110 , the gaps  113  making it easier to disengage the flange  113 D from the lip  110 A as they permit the perimeter of the cap  113  to be enlarged as it is lifted off the container  110 . The thread-like formations  113 B of the cap provide lips that can be lifted to help peel off the cap  113 . 
         [0067]    In the closed position, each of the flaps  113 C is folded up to engage the collar  114  and is preferably then welded thereto so that when the collar  114  is twisted to remove it, the flaps  113 C remain attached thereto and tear off the cap  113  along the lines of the living hinges to provide visual tamper evidence. 
         [0068]      FIG. 9C  shows a vertical sectional view through a fifth embodiment in which the closure means comprises a foil  150  and a collar  151  and  FIGS. 9A and 9B  show perspective and plan views of the collar  151 . 
         [0069]    The collar comprises a first part  151 A with a gap therein and a second part  151 B which can be connected to the first part  151 A to join the ends of the first part  151 A. The second part  151 B hooks to one end of the first part  151 A and has an over-centre mechanism  151 C such that when moved to the closed position it remains in this position and puts the collar  151  under tension so as to clamp it more securely about the container  152  and foil  150 . As shown in  FIG. 9C , the collar  151  is shaped to engage under a lip  152 A of container  152  and is arranged to grip the foil  50  tighter as the collar is tightened. 
         [0070]    Part  151 B is provided with a tab  151 D which may be lifted like a conventional ring-pull to break the collar at one or more weak points  151 E when it is desired to remove the collar  151  to open the container. This action may also pierce the foil  150 . 
         [0071]    In the above arrangements in which the foil is bonded to the container, the bond therebetween is strong when subject to shear forces, i.e. forces in the plane of the bond, but weak when subject to peel forces, i.e. forces out of the plane of the bond which tend to separate the foil from the container. 
         [0072]    The second aspect of the present invention arises from the realisation that the ability of the bond to withstand forces acting on the foil as a result of pressure within the container can be improved or optimised in arrangements which reduce or inhibit the forces created by internal pressure from applying peel forces to the bond. 
         [0073]    As pressure within the container rises, the foil tends to bow or be deflected outwards. In conventional arrangements, this changes the angle at which forces within the foil are applied to the bond with the container so tends to apply peel forces thereto whereby the foil begins to separate from the container, even as a result of relatively small increases in the internal pressure. 
         [0074]    In the embodiments described above, this tendency is reduced when a holding component such as a cap or collar is provided which provides physical support for the foil. The cap or collar limits the extent to which the foil can be deflected by internal pressure and thus limits the change in angle of the forces applied by the foil to the bond. Alternatively, or additionally, the cap or collar may re-enforce the connection between the foil and the container by being positioned directly over the area where the foil is bonded to the container, thus inhibiting movement of the foil away from the container and/or preventing the foil in the area of the bond from deflecting to any significant extent (even if areas of the foil away from the bond are subject to significant deflection) so reducing the tendency for the foil to apply peel forces to the bond area. A collar that encircles the container and may also assist in holding the foil against the lip and/or the external surface of the container. 
         [0075]    As mentioned above, and as shown for examples in  FIGS. 5 ,  8 B and  9 C, the container has a lip the outer portion of which has a curved profile and the foil preferably extends around this curved profile and is bonded thereto. The area of foil bonded to the container is thus increased compared to arrangements having only a narrow bond area at the uppermost part of the lip. The foil may also extend under the lip and may be bonded to the underside of the lip. In addition, the foil may extend beyond the lip and be bonded to the external surface of the container. 
         [0076]      FIGS. 10A and 10B  illustrate a further way of reducing peel forces due to internal pressure. In these arrangements, the lip of the container is shaped so as to prevent or minimise peels forces arising when the foil deflects due to internal pressure. 
         [0077]      FIG. 10A  shows a schematic, cross-sectional view of a container  160  having an opening of radius R, e.g. of 30 mm (such as might be used for a wide-mouth container). A foil  161  is bonded to a lip  162  of the container. The foil is shown bowed due to internal pressure P within the container  160  with a maximum deflection D at the centre of the foil, e.g. of 8 mm (as might arise with an aluminium foil to a pressure P of around 150-200 psi). 
         [0078]    The lip  162  is shaped so as to have a substantially flat area  162 A which is inclined outwardly relative to the axis X-X of the mouth of the container  160 . In the cross-sectional view shown, a line N normal to the flat area  160 A lies at an angle α to the axis X-X. The angle α can be deduced by geometry for a container having a radius R and a foil with a maximum deflection D. With R=30 mm and D=8 mm, the angle α is around 30 degrees. 
         [0079]    The flat area  162 A, of course, extends 360 degrees around the lip of the container and thus is part of the surface of a core centred on the axis X-X; the arrangement being such, that the bowed portion of the foil  161  is part of a spherical surface to which the conical surface is substantially tangential. Accordingly, as shown in  FIG. 10A , forces F in the foil due to the internal pressure P are applied substantially parallel to the flat surface  162 A so they apply only shear forces to the bond between the foil  161  and the surface  162 A. 
         [0080]    It will also be appreciated that when the foil is deflected by a distance less than the maximum D, it applies a force to the bond at a lower angle, the force having a first component parallel with the surface  160 A and a second component which acts downwardly, i.e. to hold the foil in contact with the surface  160 A. The arrangement is preferably such that forces applied by the foil  161  to the bond only have an upward component (which would tend to peel the foil away from the surface  160 A) if the foil  161  were to deflect by more than the maximum deflection D. Such a situation may be prevented by the nature or design of the foil  161  and/or by the provision of venting means which prevents the pressure P reaching the level required to achieve this. 
         [0081]    Alternatively, the foil  161  may be designed so that the maximum deflection D is exceeded once the pressure P reaches a certain threshold, e.g. 50 psi, to initiate venting intentionally in order to relieve the pressure P and thus avoid a catastrophic failure of the container or closure. 
         [0082]    As shown in  FIG. 10A , the outer portion  162 B of the lip  162  has a curved profile and the bond between the foil  161  and the lip  162  preferably extends around this curved profile. 
         [0083]    Also, as shown, at least part  161 A of the foil preferably overhangs the lip  162 . This part  161 A of the foil may thus form an opening member which may be gripped to lift the foil  161  away from the lip  162  (as shown in dotted lines in  FIG. 10B ) when it is desired to open the container  160 . It will be appreciated that forces applied, e.g. by a user&#39;s fingers, to lift the part  161 A of the foil apply predominantly peel-forces (as opposed to shear forces) to the bond between the foil  161  and the lip  162  thus making it relatively easy to remove the foil  161  from the container  160 . 
         [0084]    The illustrated arrangement thus takes advantage of the bond being strong in shear for withstanding pressure within the container  160  but weak under peel forces to assist a user in opening the container  160 . 
         [0085]    The arrangement shown in  FIG. 10B  is similar to that shown in  FIG. 10A  but for a foil designed to have a smaller maximum deflection D, e.g. of 5 mm. With a container having a radius R of 60 mm and a maximum deflection D of 5 mm, the angle α is then approximately 15 degrees. 
         [0086]    Whilst the above arrangements seek to minimise the peel force applied to the bond between the foil and the container by internal pressure, in some cases it may be sufficient merely to reduce rather than eliminate such peel forces. If the foil applies a force F at an angle θ to the plane of the bond, this comprises a shear component of F cos θ and a peel component of F sin θ. In known arrangements, θ may be 45 degrees or more so the peel force component exceeds the shear component. In some cases, it may be sufficient to reduce θ to less than 45 degrees so that the peel force component is less than the shear force component (although it would be preferred to minimise the angle θ). 
         [0087]    It will also be appreciated that instead of a flat surface  162 A as described above, a downwardly curving surface may be used. A radially inner portion of the bond surface (but not necessarily the inner most portion of the bond) should be orientated such that the peel forces applied thereto by the foil at the maximum deflection D are smaller than the shear forces applied thereto (and preferably as small as possible). Radially outer portions of the bonded area may, however, curve downward, e.g. as shown in  FIGS. 10A and 10B . The width of the flat area  162 A may thus be reduced in effect to zero so long as the force F remains tangential to the curved profile of the lip at a point towards the inner portion of the bonded area. 
         [0088]    In addition to the above, the foil may be constructed so as to reduce the mount by which it deflects under a given internal pressure. This may be achieved, for example, by suitable choice of materials for a laminate foil. In particular, if one layer of the laminate is more flexible or stretchable in one direction compared to a perpendicular direction, a crossed-laminate may be used, i.e. in which two such layers are orientated in different directions (preferably perpendicular to each other).