Abstract:
A shipping container for flowable material including a large rigid shipping container and a flexible tank. The shipping container has a substantially rectangular cubic configuration with common attachment regions. The flexible tank is positionable within the rigid shipping container. The flexible tank includes a generally rectangular cubic configuration. At least certain dimensions of the flexible tank corresponding to dimensions of the large rigid shipping container so that the flexible tank has a generally form fit retention within the large rigid shipping container. The flexible tank further comprises a film which together with a plurality of seals defines a substantially rectangular cubic cavity. A dispensing means is provided which extends through the film for selectively placing the cavity in fluid communication with an outside dispenser. The film comprises a layer comprising a co-extruded blend of HDPE and TPE, to, in turn minimize oxygen transmission within the film.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The invention relates in general to shipping containers, and more particularly, to a shipping container for flowable material which comprises a large outer container (i.e., a common twenty foot shipping container, or the like) and an inner flexible tank. Furthermore, the invention is directed to a flexible tank used within the shipping container. 
         [0003]    2. Background Art 
         [0004]    Shipment of flowable material in large quantity over relatively long distances has increased over the last few decades. Whereas dry cargo has been essentially revolutionized in the last 40 years, with the introduction of the standard shipping container, the ISO tank has remained the common mode of transporting flowable materials. 
         [0005]    In the past several years, however, there has been a move toward the use of flexible tanks positioned and retained within standard shipping containers for transporting relatively large shipments of flowable materials. Among other reasons, such a system allows for the use of conventional shipping containers, where a tank, after use can be folded and stored. As containers are quite standard, the folded flexible tanks can be shipped to a location, whereas the bulky rigid standard containers can be obtained locally. 
         [0006]    Great logistical advantages can be achieved through the use of flexible tanks within standard containers. Furthermore, a great cost savings is realized inasmuch as the construction costs of ISO tanks are typically quite expensive when compared to a standard shipping container and a flexible tank. 
         [0007]    While such advantages are leading a revolution in the shipment of flowable materials, there have been drawbacks. Generally, to insure safe travel of the flowable material, the flexible tanks are relatively thick and heavy duty. Whereas dispensing bag films may be on the order of 2-8 mils, the flexible tanks associated with the present invention are substantially thicker (i.e., at least approximately 15 mils and often approximately 40 mils or greater). While thick films are required, these films must have also possess qualities of flexibility, resistance to shock, the resistance to flex cracking and the ability to be sealed so as to form a substantially fluid-tight cavity. 
         [0008]    Typically, to achieve the desired strength and flexibility characteristics, the predominantly used material has been LDPE and LLDPE. Such a material exhibits relatively large oxygen transmission rates (OTR). For example, the OTR for such films is approximately on the order of twelve cubic centimeters per one hundred square inches per day. 
         [0009]    Such an OTR is quite high and can adversely affect the quality of oxygen sensitive materials when shipped any appreciable distances. For example, such an OTR makes the otherwise desirable transport system less suitable for the satisfactory shipment of wine from Australia to North America, or from Argentina to Europe. 
         [0010]    To avoid the degradation of the flowable material, one solution is to use conventional ISO tanks, or, to first package the wine into bottles or small dispensing bags (i.e., 3 to 10 liter). There is a great increase in cost with either system. One particular downside with the packaging of wine into smaller dispensing bags prior to long-haul shipment is that the bags are generally placed into small rigid paperboard boxes. In turn, if one of the thousands of bags is compromised, generally a number of rigid paperboard container of adjoining bags in the same shipment are destroyed. Thus, even a small breach in one bag can ruin a number of different bags in a single shipment. 
         [0011]    It is an object of the present invention to provide a flexible tank which has an oxygen transmission rate suitable for long haul shipment of oxygen sensitive materials. 
         [0012]    It is another object of the present invention to provide a flexible tank which is suitable for long haul shipment of wine and other oxygen sensitive materials. 
         [0013]    It is another object of the invention to provide a flexible tank film which has a relatively low oxygen transmission rate (OTR) for a relatively thick film. 
         [0014]    These objects as well as other objects of the present invention will become apparent in light of the present specification, claims, and drawings. 
       SUMMARY OF THE INVENTION 
       [0015]    The invention is directed to a shipping container for flowable material, in a first aspect. In particular, the shipping container includes a large rigid shipping container, such as a conventional twenty foot shipping container, and a flexible tank. The flexible tank is positionable within the rigid shipping container. The flexible tank includes a film having a plurality of seals to define a cavity, and a dispensing means for dispensing a flowable material positioned within the cavity. The film includes a layer comprising a co-extruded blend of HDPE and TPE, to, in turn minimize oxygen transmission within the film. 
         [0016]    In a preferred embodiment of the invention, the film comprises a thickness of at least 15 mils, and more preferably at least 30 mils. 
         [0017]    In another preferred embodiment, the cavity of the flexible tank is between 10,000 and 30,000 liters, and preferably at least 20,000 liters. 
         [0018]    In yet another preferred embodiment, the film comprises a co-extrusion with the layer comprising the product contact layer. 
         [0019]    In certain embodiments, the layer of the film further comprises at least one of EVOH, Nylon, PET, an oxygen scavenger and anhydride-modified PE. 
         [0020]    In other embodiments, the film may include a second layer comprising at least one of an LLDPE and an LDPE material. The second layer is positioned about the first layer. 
         [0021]    In another aspect of the invention, the film further includes a third layer comprising at least one of an LLDPE and an LDPE material. The third layer positioned about the first layer opposite the second layer. 
         [0022]    Preferably, the layer, the second layer and the third layer are co-extruded. 
         [0023]    Most desirably, the film has an OTR, the OTR of the film being less than six cubic centimeters per one hundred square inches per day, and wherein the film is at least 30 mils in thickness. 
         [0024]    In another aspect of the invention, the invention comprises a flexible tank for use in association with a rigid shipping container for the transport of flowable material. The flexible tank comprises an oxygen sensitive flowable material. The flexible tank is positionable within the rigid shipping container. The flexible tank includes a film having a plurality of seals to define a cavity, and a dispensing means for dispensing a flowable material positioned within the cavity. The film comprises a layer having a co-extruded blend of HDPE and TPE, to, in turn minimize oxygen transmission within the film. 
         [0025]    In another aspect of the invention, the invention comprises a shipping container for flowable material which includes a large rigid shipping container and a flexible tank positioned within the rigid shipping container. The shipping container has a substantially rectangular cubic configuration with common attachment regions. The flexible tank is positionable within the rigid shipping container. The flexible tank includes a generally rectangular cubic configuration. At least certain dimensions of the flexible tank corresponds to dimensions of the large rigid shipping container so that the flexible tank has a generally form fit retention within the large rigid shipping container. The flexible tank further comprises a film which together with a plurality of seals defines a substantially rectangular cubic cavity. A dispensing means is provided which extends through the film for selectively placing the cavity in fluid communication with an outside dispenser. The film comprises a layer comprising a co-extruded blend of HDPE and TPE, to, in turn minimize oxygen transmission within the film. 
         [0026]    In a preferred embodiment, the film comprises a thickness of at least 30 mils and has an OTR of less than six cubic centimeters per one hundred square inches per day. 
         [0027]    In another preferred embodiment, the film includes a second layer extending about the first layer and a third layer extending about the second layer. The second and third layers comprising at least one of an LLDPE and an LDPE material. 
         [0028]    In another preferred embodiment, the large rigid shipping container comprises a standard twenty foot container. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0029]    The invention will now be described with reference to the drawings wherein: 
           [0030]      FIG. 1  of the drawings is a perspective view of a shipping container having the flexible tank of the present invention; 
           [0031]      FIG. 2  of the drawings is a perspective view of a flexible tank in the articulated configuration; and 
           [0032]      FIG. 3  of the drawings is a partial enlarged cross-sectional view of one embodiment of a film which is suitable for use in association with the flexible tank of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0033]    While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and described herein in detail a specific embodiment with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the embodiment illustrated. 
         [0034]    It will be understood that like or analogous elements and/or components, referred to herein, may be identified throughout the drawings by like reference characters. In addition, it will be understood that the drawings are merely schematic representations of the invention, and some of the components may have been distorted from actual scale for purposes of pictorial clarity. 
         [0035]    Referring now to the drawings and in particular to  FIG. 1 , a shipping container for flowable material is shown generally at  10 . The shipping container includes a large rigid outer container  20  and inner flexible tank  30 . The large rigid outer container preferably comprises a standard twenty foot container. Typically, such a container has a twenty foot length an eight foot width and an eight foot, six inch height. This is commonly referred to as a TEU, or twenty four equivalent unit. These types of containers have a maximum payload of approximately 21,600 kg and a gross weight of 24,000 kg (with a volume of approximately 38,500 liters). 
         [0036]    Such containers are popular and available virtually everywhere in the world. Furthermore, other containers, such as forty foot containers, forty-five foot containers, forty-eight foot containers and fifty-three foot containers are likewise contemplated, however, with most flowable material, a container larger than the twenty foot container is typically heavier than the permissible gross weight of the filled container. However, the invention is not limited to any particular sized container, but is quite suitable for conventional shipping containers. 
         [0037]    Such containers include a rectangular cubic configuration having a top surface  70 , a bottom surface  72 , opposing side surfaces  74 ,  76 , front surface  78  and back surface  80 , all of which cooperate to define inner space  85 . The top surface  70  opposes the bottom surface  72 . One of the front surface  78  and the back surface  80  comprise a pair of doors  82 ,  84  which provide ingress to inner space  85 . Typically the doors are hinged about the edges of the opposing side surfaces  74 ,  76  and include clasps and locking mechanisms (not shown) to retain the doors in the closed configuration. 
         [0038]    The flexible tank  30  is shown in  FIG. 2  as comprising a plurality of panels of film  40  which are sealed to each other by way of seals  42  to form a substantially rectangular cubic configuration. Specifically, the flexible tank comprises top surface  90 , bottom surface  92 , opposing side surfaces  94 ,  95 , front surface  96  and back surface  98 . Seals and/or folds define the demarcation of the various panels of the flexible tank. Typically the volume of the rigid outside container is on the order of approximately 38,500 liters, and the flexible tank may have a volume which is as large as inner space  85  (minus any volume taken by the flexible tank film and other structures, and any other necessary equipment. More typically, the volume of the flexible tank is between 10,000 and 30,000 liters per TEU of the outer rigid container, and more preferably at least 20,000 liters. 
         [0039]    A dispensing means  46  is provided on one of the front and back surfaces or on one of the top or bottom surfaces. The dispensing means may comprise a spout having a fitment integrated therewith or separately positioned thereon. The dispensing means may comprise a plurality of spouts which are positioned in a spaced-apart relationship along any one or more of the panels. Indeed, it is contemplated that multiple spouts may be provided so that one spout can be used for filling and another for removing the flowable material. In other embodiments, multiple filling spouts and dispensing spouts may be provided. Furthermore a vent (not shown) is typically provided on the top of the flexible tank so as to release any air captured within the cavity. 
         [0040]    The dispensing means is positioned such that access can be gained thereto when the flexible tank is positioned within the rigid outer container. In many instances, a bottom discharge means comprising a valve is utilized, while top discharge locations are likewise contemplated. Of course, in other embodiments, where is desirable to limit the access to the dispensing means, the dispensing means can be moved away from the region proximate the doors of the outer rigid container. 
         [0041]    With reference to  FIG. 3 , the flexible tank film  40  most preferably comprises a three layer co-extrusion having an outer layer  54  comprising a low density polyethylene (LDPE) and/or a linear low density polyethylene (LLDPE) material, an inner layer  52  likewise comprising a LDPE and/or LLDPE material and a layer  50  comprising a blended high density polyethylene material (HDPE) and a thermoplastic elastomer (TPE). Due to the rugged environment and vast distances covered by such containers, the film comprises a thickness of at least 15 mils, and more preferably at least 30 mils or greater. In a preferred embodiment, the thickness is approximately 40 mils wherein the outer layer  54  has a thickness of approximately 7 mils, the inner layer  52  has a thickness of approximately 7 mils, and the layer  50  has a thickness of approximately 26 mils. As far as ratios, the different layers may have relative thicknesses of 20/60/20, 5/90/5 as well as a number of different ratios as well. Furthermore, carbon black may be included in certain layers to provide an opaqueness to the flexible tank. 
         [0042]    Whereas HDPE, while a vastly improved oxygen barrier over LDPE or LLDPE, lacks the necessary characteristics (strength, ductility, flex cracking resistance, etc.) to be useful for such a container, it has been found that, surprisingly, HDPE along with TPE, in a blended co-extrusion yields a final layer which has a vastly improved oxygen transmission as compared to LDPE or LLDPE, while having strength, ductility, and flex cracking characteristics which are substantially similar to LDPE/LLDPE. Additionally, and again quite surprisingly, the combination of the blended HDPE and TPE can be co-extruded with layers of LDPE and/or LLDEP. The performance of the HDPE and TPE blend, especially for relatively thick films has been rather unexpected. It will be understood that in certain embodiments, it may be desirable to utilize a single layer co-extrusion of the blended HDPE and TPE where it forms the product contact layer. It is also contemplated that a two layer co-extrusion can be provided wherein the second layer comprises an LDPE or LLDPE layer. 
         [0043]    In a preferred embodiment, the HDPE and TPE blend comprises a 60% HDPE to 40% TPE blend, while other combinations are likewise contemplated. It will be understood that in certain formulations, EVOH, Nylon, PET, oxygen scavengers and/or anhydride-modified Polyethylene (PE) may be included in the blended HDPE and TPE. Furthermore, additional layers may be present which include PE, EVOH, Nylon, oxygen scavengers, PET and/or anhydride-modified PE. It will be understood that certain of the layers may be laminated onto the blended HDPE and TPE layer. 
         [0044]    Whereas such large flexible tanks are formed from ˜0.918 g/cc density butene, hexene and/or octene LLDPE, such materials include a oxygen transmission rate (OTR) or approximately twelve cubic centimeters per one hundred square inches per day. By replacing the layer  50  with a HDPE and TPE blend of the present invention, the OTR can be reduced to approximately five cubic centimeters per one hundred square inches per day. Thus the OTR can be reduced by a factor of two and a half. Indeed, a HDPE/TPE blend has an OTR that is three to six times lower than LLDPE, while having the same stiffness, as well as similar strength, flex crack resistance and shock absorption. 
         [0045]    In use, typically, the flexible tank is provided in a collapsed condition. It is subsequently installed into a rigid outer container. The two are sized such that the flexible tank fits within the rigid outer container substantially snugly (while there may be open space between the top of the flexible tank and the top panel of the outer container. 
         [0046]    Once fitted, structures may be provided to attach portions of the flexible tank to the outer rigid container, to, in turn, support the flexible tank in an articulated position when empty. The flexible tank can then be filled through the dispensing means. Once filled as desired, the flexible tank can be sealed and the rigid outer container can be closed so as to preclude ingress into the container. 
         [0047]    The container can then be shipped to a destination as desired. Once at a destination, the flexible tank can be emptied. It may be emptied at once or in stages. Inasmuch as air is typically not directed into the flexible tank, the flexible tank collapses as it empties. Once emptied, the user can, if necessary, disconnect the flexible tank from the outer container. Next, the user can remove and discard the flexible tank. 
         [0048]    Advantageously, a number of the flexible tanks can be collapsed and placed into a single container. Subsequently, they can be shipped in that container to a filling destination. Once at the destination, containers can be obtained locally, and each flexible tank can be articulated in a separate container. As such, great advantages in shipping can be achieved over ISO tanks inasmuch as the flexible tanks can be collapsed when not in use, and the ubiquitous shipping containers can be sourced at the filling location. 
         [0049]    The foregoing description merely explains and illustrates the invention and the invention is not limited thereto except insofar as the appended claims are so limited, as those skilled in the art who have the disclosure before them will be able to make modifications without departing from the scope of the invention.