Abstract:
A container ( 51 ) for storage and dispensing of fluids, comprising collapsible front ( 54 ) and rear walls ( 56 ) defining a chamber, having a gland ( 50 ) defining a fluid passage for allowing the passage of fluids into the chamber carried on the front wall ( 54 ) of the container ( 51 ). The gland ( 50 ) includes a sealing land ( 59 ) within the container for sealingly engaging a heat sealable membrane ( 61 ) along a continuous seal upon the application of heat through the rear wall ( 56 ) of the container. The sealing land ( 59 ) in a pre-sealed condition, includes at least one thermo-deformable projection ( 64 ) having a raised profile providing an initial melt zone of reduced area relative to the area of the sealing land.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a sealable container, and to a method of sealing such a container. In particular, the invention relates to an aseptically sealable container, as well as to an aseptic seal for said container and an associated aseptic packaging fitment. 
       BACKGROUND OF THE INVENTION 
       [0002]    Filling of pre-sterilised containers in an aseptic manner is known and various systems are employed which utilise different filling apparatus, different containers, and different sterilisation techniques. Typically, the container to be filled is produced in such a way as to ensure that the interior of the container is sterilised during manufacture. During the filling procedure, an inlet into the container is opened and a filling nozzle is used to fill the container with flowable material. The inlet is then sealed to thereby contain the flowable material within the container until dispensing is required. The resealing of the container after it is filled must be done in such a way that a proper seal is achieved so that contamination does not take place during subsequent storage and transportation. 
         [0003]    Several related art patents have addressed the aforementioned problems such as the devices and methods disclosed in U.S. Pat. No. 4,257,535 (Mellett), U.S. Pat. No. 4,672,688 (Kalkipsakis) and U.S. Pat. No. 4,805,378 (Anderson), each of which describe systems providing a sealable container having a filling port which is sealed from within the container. 
         [0004]    U.S. Pat. No. 4,257,535 and U.S. Pat. No. 4,672,688 describe a container having an internal flap integral with the wall of the container. Once the container is filled, the filling port is sealed by urging the flap against a flange on the port, and heat sealing the flap to the filling port via a heating device located outside of the container so as to form an annular heat seal. U.S. Pat. No. 4,805,378 describes a similar device and method. In other applications of the related art, an internal membrane is not used, rather the rear wall of the flexible container itself forms the welded closure. 
         [0005]    The temperature required for sealing the port as described in U.S. Pat. No. 4,257,535, U.S. Pat. No. 4,672,688 and U.S. Pat. No. 4,805,378 is typically in the range of from 160° C. to 225° C., depending upon material characteristics and combined thicknesses of the rear container wall and the flap or membrane. 
         [0006]    The above described documents provide a filling method that is commonly used in the aseptic and conventional packaging of fruit and vegetable pulp, juices and dairy products. 
         [0007]    When using currently known devices and methods for the containment of fibrous and particulate products as discussed above, difficulty may be experienced in achieving satisfactory heat seals without entrapment of fibrous materials and particles within or across the seal. Another disadvantage experienced is the extended time required for heat penetration into the package from the external heat source under the limitations of the maximum temperature able to be employed without damage to the outer package layers. 
         [0008]    A further disadvantage is experienced when alternative methods of heat sealing such as ultrasonic sealing are employed, whereby the ultrasonic transducer tends to damage the rearmost walls of the container configured as disclosed in the prior art, and does not achieve a satisfactory seal between the inner membrane and the filling port. The frictional energy required to perform the seal tends to be dissipated between the layers of intervening materials when sealing is attempted over an annulus of similar dimensions to conventional heat sealing methods. 
         [0009]    Any discussion of documents, publications, acts, devices, substances, articles, materials or the like which is included in the present specification has been done so for the sole purpose so as to provide a contextual basis for the present invention. Any such discussions are not to be understood as admission of subject matter which forms the prior art base, or any part of the common general knowledge of the relevant technical field in relation to the technical field of the present invention to which it extended at the priority date or dates of the present invention. 
       SUMMARY OF THE INVENTION 
       [0010]    In broad terms, the present invention provides a container for storage and dispensing of fluids, said container comprising collapsible front and rear walls defining a chamber, a gland defining a fluid passage carried on the front wall for allowing the passage of fluids into the chamber, the gland including a sealing land within the container for sealingly engaging a heat sealable membrane along a continuous seal upon the application of heat through the rear wall of the container, wherein the sealing land, in a pre-sealed condition, includes at least one thermo-deformable projection having a raised profile providing an initial melt zone of reduced area relative to the area of the sealing land. 
         [0011]    Preferably, the gland extends through an aperture defined in the collapsible front wall of the container, and includes a base flange located within the container, the sealing land being annular and being defined on an innermost face of the base flange, and the deformable projection comprising at least one annular lip. 
         [0012]    Advantageously, the annular lip is shaped to define a cutting edge and is formed with at least one deflection surface for deflecting matter away from the Initial melt zone upon the sealable membrane and the sealing land being urged towards one another. 
         [0013]    The annular lip is preferably shaped so as to be generally triangular in cross-section, the apex of the triangular section defining the cutting edge. 
         [0014]    Preferably the container is formed from a flexible heat resistant material which allows the heat sealable membrane to be abutted against the sealing land from the interior of the container by compressing and urging a portion of the wall of the container towards the sealing land and which allows heat to be transferred through the rear wall by a heating element to the melt zone. Advantageously the sealing membrane is carried on the sealing land prior to sealing. 
         [0015]    Preferably, the heat seaelable membrane includes a thermoplastic heat sealable layer proximate the sealing land for allowing the seal to be formed, and a distal non-heat sealable layer to prevent adherence of the sealing membrane to an inner surface of the rear wall of the container, prior to the heat sealable membrane being heat sealed to the sealing land. 
         [0016]    The heat sealable membrane may be carried on the rear wall of the container prior to being heat sealed to the sealing land. 
         [0017]    Preferably, the gland may include a rupturable membrane extending across an external opening of the passage such that the container is sealed prior to ingress of fluid into the container. The membrane may be rupturable by a delivery means, the delivery means being engageable with the gland prior to rupture of the rupturable membrane to provide for aseptic delivery of a fluid into the container. 
         [0018]    Preferably the container includes a sealing land and a thermoplastic layer of the sealing membrane which are formed from thermoplastic materials adapted to melt and form said seal at a temperature in the range between 100° C. and 265° C. 
         [0019]    More preferably the sealing land and a heat sealable layer of the sealing membrane may be formed from thermoplastic materials adapted to melt and form said seal at a temperature between 130° C. and 200° C. 
         [0020]    Advantageously, the sealing land may include a plurality of annular thermo-deformable projections in a spaced apart relationship. 
         [0021]    The present invention also provides a gland defining a passage for providing a fluid pathway for delivery into and dispensing from a collapsible container comprising front and rear walls defining a chamber, the gland mountable within an aperture on the front wall of the container, the gland including a sealing land within the container for receiving a heat sealable membrane which is arranged to be heat sealed through the rear wall of the container to form a continuous seal wherein said sealing land, in a pre-sealed condition, includes at least one thermo-deformable projection having a raised profile providing an initial melt zone of reduced area relative to the area of the sealing land. 
         [0022]    Preferably the gland is of generally annular form and the at least one deformable projection of the sealing land extends circumferentially around the passage to define a cutting edge prior to deformation to sever any fibrous material present between the deformable projection and the sealing membrane upon abutment to the container with a heating means. 
         [0023]    Advantageously, the deformable projection may be of a generally triangular cross-section, the apex of the triangle defining a cutting edge. 
         [0024]    Preferably the gland includes a rupturable membrane which, prior to rupture, extends across the passage so as to seal the passage of the gland prior to the ingress of contents. 
         [0025]    More preferably, the gland may be engageable with a fluid delivery means in a manner so as to be ruptured upon engagement with the fluid delivery means. 
         [0026]    In still a further aspect of the invention there is provided a method of sealing the gland of a container, the method comprising the steps of:
       providing a container having front and rear walls defining a chamber, and a gland carried on the front wall, the gland having a first end, a second end and a passage therethrough, the gland including a sealing land within the container for receiving a heat sealable membrane which is arranged to be heat sealed to the sealing land along a continuous seal, said sealing land, in a pre-sealed condition, including at least one projection having a raised profile for providing an initial melt or heat zone of reduced area relative to the area of the sealing land;   providing a heat sealable membrane adjacent the sealing land and extending over the passage of the gland; and   applying heat through the rear wall of the container to the heat sealable membrane using a heating means, and urging the heat sealable membrane and the sealing land towards each other;
 
wherein the deformable projection is configured such that upon abutment with the heat sealable membrane, the deformable projection and a thermoplastic layer of the sealable membrane are melted to form a seal between the heat sealable membrane and the sealing land thereby sealing the passage.
       
 
         [0030]    Preferably the heating means provides conductive and/or convective heat energy to the deformable projection and the sealable membrane. The heating means may heat the deformable projection and the sealable membrane by frictional energy or by ultrasonic energy. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0031]    The invention now will be described by way of example only, and with reference to the accompanying drawings in which: 
           [0032]      FIG. 1   a  shows a part sectional view of a gland and container of the related art prior to sealing; 
           [0033]      FIG. 1   b  shows an enlarged spot-sectional view of the gland and container of  FIG. 1   a;    
           [0034]      FIG. 1   c  shows a part sectional view of the gland and container of  FIG. 1   a  after sealing; 
           [0035]      FIG. 1   d  shows an enlarged spot-sectional view of the gland and container of  FIG. 1   c;    
           [0036]      FIG. 2   a  shows a part sectional view of a first embodiment of a gland and container according to the present invention prior to sealing; 
           [0037]      FIG. 2   b  shows an enlarged spot-sectional view of the gland and container of  FIG. 2   a;    
           [0038]      FIG. 2   c  shows a part sectional view of the gland and container of  FIG. 2   a  after sealing; 
           [0039]      FIG. 2   d  shows an enlarged spot-sectional view of the gland and container of  FIG. 2   c;    
           [0040]      FIG. 2   e  shows apartly cutaway underplan view of the gland of  FIG. 2   a;    
           [0041]      FIG. 2   f  shows a triangular profile of a deformable projection in an embodiment of the gland of  FIG. 2   a;    
           [0042]      FIG. 2   g  shows a trapezoidal profile of a deformable projection in an alternative embodiment of the gland of  FIG. 2   a;    
           [0043]      FIG. 2   h  shows a rounded profile of a deformable projection of the gland in a further alternative embodiment of the gland of  FIG. 2   a.    
           [0044]      FIG. 3   a  shows a part sectional view of a second embodiment of a gland and container according to the present invention prior to sealing; 
           [0045]      FIG. 3   b  shows an enlarged spot-sectional view of the gland and container of  FIG. 3   a;    
           [0046]      FIG. 3   c  shows a triangular profile of the deformable projections of the gland of  FIG. 3   a;    
           [0047]      FIG. 3   d  shows a trapezoidal profile of the deformable projections of an alternative embodiment the gland of  FIG. 3   a ; and 
           [0048]      FIG. 3   e  shows a rounded profile of the deformable projections of a further alternative embodiment the gland of  FIG. 3   a;    
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0049]    The following description refers to preferred embodiments of a sealable container according to the present invention. To facilitate an understanding of the invention, reference is made in the description of the accompanying drawings whereby a gland as provided by the related art is described, and a gland according to the present invention is illustrated in a preferred embodiment. 
         [0050]    Referring to  FIGS. 1   a  to  1   d , there is shown a gland  10  for sealing a container as typified by devices of the related art. The related art gland  10  is of general tubular form, sealed to a package or container  12  typically comprising one or more plastic film layers forming a front wall  14 , and one or more plastic film layers forming a rear wall  16  of the container  12 . The gland  10  is formed with a base flange  18 , the outer face of which is sealed to the front wall  19  of the container  12 . A plastic film membrane  20  is partially attached to the inner face  21  of the base flange  18  at regions  23 , 24 . 
         [0051]    In this example, the gland  10  further includes a rupturable membrane  25  sealed onto a top flange  27  of the gland  10  and being located outside of the container  12  to maintain the container in a non-contaminated state and allow for aseptic filling of the container  12 . 
         [0052]    As shown in  FIG. 1   b , the flap membrane  20  allows fluid to pass between the gland  10  and the membrane  20  at zone  29 . The area in which the heat seal closure is to occur is at zone  29 , and the seal is formed via an annular contact area between the inner flat surface  21  of the base flange  18  of the gland  10  and the membrane  20 . 
         [0053]    One manner demonstrated in the related art by which the gland  10  may be sealed by the flap membrane  20  thereby sealing the container  12  is shown in  FIG. 1   c . An annular copper heating element  30  is positioned at the rear wall but not in direct contact with it until after the container  12  is filled and prepared for sealing. The heating element  30 , is advanced from the rear of the container  12  and urges the rear wall  16  towards the front wall  19  of the container  12  such that the flap membrane  20  is abutted to the innermost flange  21  at zone  32  as shown in more detail in  FIG. 1   d . This causes the flap membrane  20  to fuse with the innermost flange so as to form an annular seal and seal the container  12 . A broad annular seal contact area and indentation on melt-flow is indicated by  35 . Sufficient heat and pressure need to be applied to the outer layer of the rear wall  16  of the container  12  to achieve satisfactory sealing performance of the flap membrane  20  by the heat sealer  30 . In other examples of the related art, the rear wall  16  of the container is used as the flap. This can require the heating element  30  to be resident in the sealing position for some time in order to seal the container  12 . 
         [0054]    Referring to  FIGS. 2   a  to  2   f , a first embodiment of a gland  50  according to the present invention is shown in a container  51 . The gland  50  has a fluid passage  52  to allow for ingress of flowable material for example liquids, suspended liquids, pulps and the like into the container  51 . The container  51  has a front wall  54  and a rear wall  56 . The gland  50  includes a base flange  58 , the outer face of which is sealed to the front wall  54  of the container  51 . The inner face  59  of the base flange  58  provides a sealing land  59  for a flap membrane  61 . The gland may be sealed before filling by a film  53  extending across the passage  52 . 
         [0055]    Typically flap membrane  61 , extends over the sealing land  59 , and is arranged to be fully sealed to the sealing land  59  on application of heat from the heating element  30  through the membrane  61  in a similar manner as is outlined above with the previous reference to the related art technique. 
         [0056]    The sealing land  59  includes a deformable projection  64  having a raised profile as shown in  FIG. 2   b  and in more detail in  FIG. 2   f . The sealing land is of a width which corresponds to the width of the uppermost face  30 A of the annular heating element  30 , as well as the width of the side wall of the gland. 
         [0057]    The deformable projection  64  is shaped and sized so that when the sealing membrane  61  is abutted against the deformable projection  64  under heat and pressure, an initial melt or heat zone is formed by the deformable projection  64  relative to the rest of the sealing land  59 . Upon further pressure, the deformable projection  64  compresses and expands radially with respect to the passage  52  so as to be planar and provide a complete seal between the Flap membrane  61  and the sealing land  59 . 
         [0058]    Referring to  FIG. 2   e  the gland  50  is shown in underplan view in a pre-sealed condition. The partial flap membrane  61  depicted in the figure may be attached at weld lines  65 ,  66  on the sealing land  59 . The flap membrane extends in tension across the region of the deformable projection  64  and between the weld lines. 
         [0059]    Because the flap membrane  61  is generally only partially attached to the gland at the weld lines  65 , 66  in the pre-sealed condition, upon engagement with a filling head (not shown) the resilient flange portion of the gland flexes downwardly, in response to the fluid pressure on the membrane. The flexure of the gland creates a void between the membrane  61  and the sealing land  59  allowing the sideways passage of fluid between the sealing membrane  61  and the sealing land  59  as indicated on the figure by arrows. 
         [0060]    Turning to  FIG. 2   f , it can be seen that an embodiment of the deformable projection  64  has a generally triangular cross section, tapering to a pointed apex region  67  defining a cutting edge. The severing of fibres present between the sealing land  59  and the sealable membrane  81  reduces the incidence of fibrous material extending through the seal formed between the sealing membrane  56  and the surface of the land  54 , thus reducing the likelihood of such fibres compromising the integrity of the seal. This provides for a more reliable seal. 
         [0061]    In an alternate embodiment of the present invention shown in  FIG. 2   g , the deformable projection  64  has a generally trapezoidal profile, with a flattened top region  68 . This profile may assist in urging any fibrous material or other particles that may be trapped between the membrane  61  and the sealing land  59  immediately prior to the sealing process away from the sealing region. The combination of heat from the heating element and pressure cooperate to deform the projection and urge the material away from the sealing region. 
         [0062]    In still a further embodiment of the present invention shown in  FIG. 2   h , the deformable projection  64  has a generally rounded profile  71  which may also assist in urging fibrous and particulate material away from the sealing region during the sealing process. 
         [0063]    The deformable projection  64 , shown in the present embodiments of the invention, may be in the form of an annular lip extending around the passage  52  of the gland  50 . The annular lip need not be continuous and may exist in the form of discrete entities which, upon application of heat and pressure, deform collectively to form the sealing land  59 . In alternate embodiments, there may exist one or more continuous or discontinuous annular lips which, when heated and compressed, form the surface of the sealing land  59 . 
         [0064]    Furthermore, the annular lip has the additional feature of urging material such as seeds or pips, or other such particles away from the region at which the seal is to be initiated, thus providing for a complete seal in at least the initial deformation region. As will be appreciated, by ensuring a complete seal in at least one portion of the sealing land, the gland may be effectively and reliably sealed. Still further, the triangular cross-section of the annular lip as described in reference to the embodiments of the present application provides an initial wedge effect which may drive seeds or pips outwardly away from the initial melt zone as the heat sealable membrane is urged against the annular rib. 
         [0065]    The alternate deformable projection profiles provided enhance localised heating and deformation of the projection, and may assist in severing of fibrous material and driving particulates away from the initial melt zone. The use of further alternate profiles according to various applications allows for further enhancement of localised heating thus providing a more efficiently and effectively formed seal. 
         [0066]    Referring to  FIGS. 5   a  to  3   b  a further embodiment of a gland  80  according to the present invention is shown. The gland  80  has a fluid passage  82  and the includes two deformable projections  84 , 86  in the form of concentric projections having a raised profile, (concentric with respect to the fluid passage  82  of the gland) extending from the sealing land  89 . 
         [0067]    Again, the deformable projections  84 , 88  are shaped and sized such that when a sealing membrane  91  is abutted against the deformable projections  84 , 86  under heat and pressure, the gland  80  is sealed in a similar manner as described with reference to the previous embodiments. Two initial heat or melt zones are provided by the deformable projections  84 , 86  relative to the remaining part of the sealing land  89 . Both deformable projections  84 , 86  upon application of heat and pressure, are deformed towards the rest of the sealing land  89  as well as both radially inward and outward. 
         [0068]    Turning to  FIG. 3   c , it can be seen the deformable projections  84 , 86  of the gland of  FIG. 3   b  may be generally triangular in cross section, tapering to a pointed apex region  95  defining a cutting edge. The severing of fibres present between the sealing land  89  and the sealable membrane  91  reduces the incidence of fibrous material extending through the seal formed between the sealing membrane  91  and the surface of the sealing land  89 , thus reducing the likelihood of such fibres compromising the integrity of the seal, thereby providing a more reliable seal. 
         [0069]    In an alternate embodiment of the present invention shown in  FIG. 3   d , the deformable projections  84  may have generally trapezoidal profiles  97 . This profile may assist in urging any fibrous material or other particles that may be trapped between the membrane  91  and the sealing land  89  immediately prior to the sealing process away from the sealing region. The combination of heat from the heating element and pressure cooperate to deform the projection and urge the material away from the sealing region. 
         [0070]    In still a further embodiment of the present invention shown in  FIG. 3   e , the deformable projection  84  may have a generally rounded profile  99  which may also assist in urging fibrous and particulate material away from the sealing region during the sealing process. 
         [0071]    The present invention, by providing a localised heating zone for the sealing lands  59 , 89  in the form of the deformable projections  64 , 84 , 86  may substantially reduce the temperature required of the heating element to form the seal. Still further, the time taken to perform the seal may be substantially reduced. Alternatively both the temperature required and the time taken to perform the seal may be substantially reduced in comparison with methods and devices of the related art which typically require a heating element temperature of 180 degrees Celsius to 200 degrees Celsius and a dwell time of 1.5 seconds- to 4 seconds. The temperature of the heating element may be reduced to 140 degrees Celsius to 150 degrees Celsius for the same dwell time using the gland of the present invention. 
         [0072]    The time taken to form a seal may be substantially reduced by up to about 30% or more. In turn, this means the incidence of damage to the container during sealing due to elevated temperatures and pressures is reduced, and the incidence of damage is also reduced due to the reduced cycle time taken to effect the seal. For sealable containers, for example those with a volume of 3 to 4 litres, this can mean a significant reduction in the total filling and sealing cycle time. 
         [0073]    As described with reference to the embodiments shown in  FIGS. 3   a  to  3   c , the deformable projections  84 , 86  of the gland  80  may be provided in the form of an annular lip of a generally triangular cross-section extending around the passage  72  of the gland  80 . 
         [0074]    In the embodiments shown in  FIGS. 3   a - 3   c  and  FIGS. 2   a - 2   f  the deformable projection  64 ,  84 , 86 , extends about 0.75 mm to 1 mm from the rest of the sealing land  59 , 89  and has an apex defining a cutting edge. The triangular cross-section of the lip is preferably of equilateral triangular form and a base width of about 0.75 mm to 1 mm. The sealing land preferably has a width of in the range of from about 3 mm to about 5 mm. A significant advantage provided by the present invention is a gland  50 , 80  which provides a more reliable seal, even in the event that a heating means or ultrasonic transducer is misaligned with the sealing land  59 , 89 . In such an event, the deformable projection(s)  64 , 84 , 86  which first contact the heating means or ultrasonic transducer with a flap membrane  61 , 91  disposed therebetween will form an initial melt zone and deform preferentially towards the rest of the sealing land surface  69 , 89  until the remaining part of the undeformed deformable projection is abutted with the heating means or ultrasonic transducer, which in turn becomes heated and deformed. 
         [0075]    As will be appreciated, when misalignment occurs between a heating means or ultrasonic transducer and a gland of the prior art, the sealing land of the gland which is initially contacted and heated would need a significant amount of heat, pressure and time so as to be deformed to an extent that the remaining portion of the sealing land was then contacted and heated to form a suitably heated surface to effect a reliable seal. As significant heat, temperature and pressure would be required the sealable membrane and/or container wall may be destroyed or at least partially compromised, resulting in an incompletely or weakly sealed gland, in comparison with that provided by the device and method according to the present invention. 
         [0076]    During filling processes of containers of a relatively low volume whereby the time taken to seal a container is a significant portion of the filing and sealing cycle, it will be appreciated that the present invention provides a significant time reduction in the cycle whilst providing a reliable seal which allows for imperfections in alignment during the sealing cycle when used with both large and small volume containers. 
         [0077]    A further feature provided by the present invention as embodied in the first and second embodiments may be the ability of the annular lip, at least initially to sever fibrous material which may be present between the sealing land  59 ,  89  as discussed previously. This reduces the incidence of fibrous material extending through the seal formed between the sealing membrane  61191  and the sealing land  59 , 89  thus reducing the likelihood of such fibres compromising the integrity of the seal, thereby providing a more reliable seal. 
         [0078]    Furthermore, the annular lip has the additional feature of urging material such as seeds or pips, or other such particles away from the region at which the seal is to be initiated, thus providing for a complete seal in at least the initial deformation region. As will be appreciated, by ensuring a complete seal in at least one portion of the sealing land, the gland may be effectively and reliably sealed. Still further, the triangular cross-section of the annular lip as described in reference to the embodiments of the present application provides an initial wedge effect which may drive seeds or pips outwardly away from the initial melt zone as the heat sealable membrane is urged against the annular rib. 
         [0079]    It will also be appreciated that the high pressure and reduced surface area contact point thus formed between the sealing land  59 , 89  and the sealing membrane  61 , 91  as provided by the present invention concentrates the transfer of heat between the two parts and initiates the progression of melting and co-mingling of the compatible materials more quickly and efficiently than a broader contact area as described in the prior art. 
         [0080]    Furthermore, in related art glands, in which the sealing gland is uni-planar and the annular heating element is similarly uni-planar, any misalignment where the planes of the respective heating element and sealing gland are not parallel will tend to compromise the seal, or alternatively increase the time and/or temperature required to perfect the seal. In the present invention, the relatively rapid deformation of the raised profile under suitable conditions of heat and pressure will tend to be self-correcting in a situation where the plane of the annular heating element is not uniformly parallel with the plane defined by the upper edge of the raised profile. 
         [0081]    The injection moulded gland may be produced from polyethylene of densities and properties ranging from low density, “linear low density”, medium density to blends with a high density component. The polyethylene density is chosen to optimise various parameters for the gland, including rigidity, flex, melt-flow and temperature resistance required. 
         [0082]    The bag wall materials may be made up of multiple layers in order to provide the required attributes of barrier, moisture resistance, physical strength and heat sealability. 
         [0083]    Typically the inner layers in contact with the product are low density polyethylene in various forms, either as free layers or as an inner layer bonded or laminated to a poly amide (nylon) layer or polyester layer. In the latter case, the resulting laminate may also include an additional layer, such as aluminium foil, PVDC, EVOH, the layer selected to provide properties such as gas, moisture or light barriers. The sealing land  59 , 89  and the sealing membrane,  61 , 91  are formed from materials which allow for co-mingling upon softening or melting so as to form the required seal. Numerous materials may be used, in particular thermoplastic polymeric materials, such as high density polyethylene (HOPE). 
         [0084]    The sealing land and the sealing membrane are typically formed from polymeric materials which flow at localised temperatures in the range of from 130° C. and 200° C. so as to effect the seal. However, it will be appreciated that alternate polymeric materials which flow so as to form the seal at localised temperatures as low as 100° C. and as high as 265° C. may be used. 
         [0085]    The sealing membranes are typically bonded laminations of various gauges. The inner face of the membrane adjacent to the gland is made from a low density polyethylene material that will suitably heat seal to the gland. The other side of the membrane is typically made from polyester (PET Film) of a grade that will not melt or heat seal to any of the polyethylene materials that are used at the temperatures specified. A polyamide material may also be used for the sealing membrane although may not have as desirable moisture absorption and extensibility properties. 
         [0086]    As with the related art, the sealing membrane may be separate from the landing surface and may be present in the form of a flap member inside the container, or even be a portion of the wall of the container, without departing from the scope and spirit of the invention. 
         [0087]    A rupturable seal  53 , 93  may be provided such that the present invention may be used in aseptic filing procedures, and the seal formed may be a hermetic seal so as to allow for the preservation of food or drink contents within the container. 
         [0088]    Various other materials may also be used for each of the gland, sealing membrane and bag. For example, polycarbonate, PVC, polypropylene and other films are in various applications in liquid packaging either as single film or in combined form as co-extrusions or laminates may be suitable, provided that the materials relative melt points, and heat sealability to each other are monitored. 
         [0089]    It will be understood that the invention disclosed and defined in this specification extends to all alternative combinations of two or more of the individual features mentioned or evident from the text or drawings. All of these different combinations constitute various alternative aspects of the invention. 
         [0090]    It will also be understood that the term “comprises” (or its grammatical variants) as used in this specification is equivalent to the term “includes” and should not be taken as excluding the presence of other elements or features.