COLLAPSIBLE CONTAINER FOR LIQUIDS

Abstract: Collapsible containers for liquids are disclosed. These containers comprise an inner bladder of plastic containing a liquid and an outer shell of Kraft paper enclosing said bladder. The containers are suitable for larger volumes of liquids, such as 3 to 500 liters. An important field of application is the large-scale transportation of water.

Description: COLLAPSIBLE CONTAINER FOR LIQUIDS The present invention relates to collapsible containers for liquids which comprise an inner bladder of plastic and an outer shell of Kraft paper enclosing said bladder. Background of the invention Most containers for liquids are rigid and need the same space whether filled or empty, such as oil barrels, plastic containers and glass bottles etc. However, there are pn the market collapsible containers for liquids, such as plastic refill-bags containing liquid detergents and, above all, milk, wine and water packages made of liquid paper board. The above mentioned collapsible containers are predominantly adapted for liquid contents of 2 liters or less, since the stability and rigidity of the containers would not easily allow larger volumes. Environmental issues high-lighted during the last few years in many countries require recycling of a larger proportion of the raw materials used. Thus, packages of all kinds are increasingly collected for re-use, recycling or energy recovery. It is obvious that collapsible containers are cheaper to transport, when empty, than containers needing the full original space. When it comes to containers for larger volumes of liquid, these are often made of plastic or steel. Even though strong Kraft paper, such as Korsnas DFDC paper, has been on the market for several years, no packages have hitherto been developed for large volumes of liquids making use of Kraft paper as an outer shell and a relatively thin liquid-impermeable material as an inner bladder. The present invention provides such collapsible, light-weight containers for liquids, e.g. liquid animal or human food. The most important field of application is the large-scale transportation and delivery of drinking-water. Description of the invention The invention is directed to collapsible containers for liquids, which comprise an inneF bladder of plastic containing said liquid and an outer shell of Kraft paper enclosing said bladder. The inner bladder is made of a flexible tube or sheet of plastic which is liquid- impermeable and heat sealable, e.g. by inductive welding. The outer shell of Kraft paper enclosing said inner bladder is made of a tube or sheet of paper and is sealed or closed with the aid of an adhesive, such as hot melt or tape. The inner bladder may be attached to the outer shell e.g. by spots of hot melt. Preferably the plastic of said inner bladder is a polyolefin, such as polyethylene, polypropylene, mixtures thereof or the like. In a preferred embodiment of the invention the plastic of the collapsible container is a polyethylene. When the collapsible container is to be used for liquid animal or human food, such as drinking water, said plastic is selected from food-grade plastics, which in most cases are virgin plastics and not recycled waste. The quality of the Kraft paper is selected inter alia to match the size of the container of the invention, preferably from one, two or multi-play sack Kraft paper. If desired, the outer Iayer of the Kraft paper may be chosen for good printing quality and thus said outer Iayer is in one embodiment white. For liquids sensitive to off-flavors, such as drinking-water, the Kraft paper should preferably be of a grade not introducing compounds causing off-flavor to said liquid. In the most simple and cheap embodiment of the invention the collapsible container only has a sealed bladder, which contains a liquid, and an outer shell of Kraft paper enclosing said bladder. After transportation, the contents of the container are tapped off by puncture of both the shell and bladder, e.g. with the aid of a knife. In another embodiment of the invention the collapsible container is equipped with a device, e.g. a screw cap, enabling the tapping off of liquid contents from said container. When said device is positioned at the lowest part of the container and the liquid is tapped off, no air will come into contact with the liquid remaining in the container. This means that adequate sterility can be maintained. In a variant of the last mentioned embodiment the container is equipped with a device comprising a valve, e.g. a tap, and enabling filling and tapping off, respectively, of liquid contents. Since the liquid contents can be tapped off without introducing air into the bladder, the collapsible container of the invention can be refilled, if desired, without extra sterilization of the container. The size of the containers of the invention may be chosen from a wide variety of sizes, e.g. adapted to liquid contents of from 3 to 500 liters. Further, the size may be adapted to standard pallets for easy lifting and transportation or to FFS or FBS standards (form fill and seal, and flexible block system respectively). Optionally, matching basket constructions may be provided. Specific examples of suitable sizes of the containers of the invention are such which are adapted to liquid contents of 5,10,15,20,25,30,40,50,60,70,80,90,100,125,150, 200, 250,300,350,400,450, and 500 liters, respectively. In a preferred embodiment of the invention, the collapsible container is used for transportation and distribution of water. In a most preferred embodiment said water is drinking-water. The container is made of renewable raw material in the form of paper and a relatively small proportion of plastic, compared with containers made of plastic only. The bladder of the container is easily separated from the paper shell. The paper may be recycled, composted or burnt. The plastic may be recycled or burnt. The energy from burning of the materials may be recovered. In this way resources are optimized. Thus, the present invention also comprises a disposable container. For ease of handling, the container of the invention may be equipped with one or several handles, e.g. made of glass-fiber reinforced tape. Such a handle will be useful in lifting and keeping the container in an upright position. The following examples illustrate the present invention. It should be noted that the raw materials used were of available qualities. Thus, the amounts of raw materials needed were not minimized or optimized. EXAMPLE 1 A heat sealable polyethylene tube of food-grade having a grammage of 140 g/m 2 was heat sealed at one end. A tube of sack Kraft paper made of 3 sheets , each having a grammage of 120 g/m 2 ( 3 X 120 DFDC-Korsnas), was sealed at one end by folding and with an adhesive. The thus formed polyethylene sack was placed into the thus formed Kraft paper sack. 30 liters of drinking-water was filled into the polyethylene sack, which was subsequently heat sealed so that no air was left into the formed bulb. The mouth of the outer Kraft paper sack was closed by folding and with an adhesive, thus enclosing said inner water-containing bladder. In this case, a reinforcing strip of paper was hot melted onto the sealed sack ends. Further, a handle of glass-fiber reinforced tape was adhered to one end of the formed container. This handle was used to lift and hang the container in an upright position. To tap off the contained water, the container was punctured with a knife at the lowest end. EXAMPLE 2 The same raw materials as in Example 1 were used. In this case the size of the container was adapted for liquid contents of 200 liters. The collapsible container was first formed with an inner bladder made from the polyethylene tube, and an outer shell of Kraft paper made from the sack Kraft paper, and additionally a device comprising a valve secured near a corner of the formed double sack. The container was placed on a standard pallet and was then filled with water with the aid of a pistol nozzle matching the device comprising a valve. The container was subsequently lifted and transported on the pallet. The contained water was tapped off in small portions with the aid of the device.

Claims: CLAIMS 1. Collapsible container for liquids, which comprises an inner bladder of plastic containing a liquid and an outer shell of Kraft paper enclosing said bladder. 2. Container according to claim 1, wherein said selected plastic is polyethylene (PE). 3. Container according to claim 1 or 2, wherein said plastic is selected from food- grade plastics. 4. Container according to any one of claims 1-3, wherein said Kraft paper is selected from one, two or multi-play sack Kraft paper. 5. Container according to claim 4, wherein said Kraft paper has a white outer Iayer. 6. Container according to any one of claims 1-5, wherein said Kraft paper is of a grade not introducing compounds causing off-flavour to said liquid. 7. Container according to any one of claims 1-6, wherein said container is equipped with a device enabling the tapping off of liquid contents from said container. 8. Container according to any one of claims 1-6, wherein said container is equipped with a device comprising a valve and enabling filling and tapping off, respectively, of liquid contents from said container. 9. Container according to any one of claims 1-8, wherein the size of said container is o adapted to liquid contents of from 3 to 500 liters. 10. Container according to claim 9, wherein said size of said container is adapted to liquid contents of 5,10,15,20,25,30,40,50,60,70,80,90,100,125,150,200,250, 300,350,400,450, and 500 liters, respectively. 11. Container according to claim 9 or 10, wherein said size is further adapted to the size of standard pallets. 12. Container according to any one of claims 1-11 , wherein said liquid is water. 13. Container according to claim 12, wherein said water is drinking water. 14. Container according to any one of claims 1-13, wherein said container is a disposable container. 15. Container according to any one of claims 1-14, wherein said container is equipped with one or several handles.

Inventors: NORDIN BENGT, NORDIN, BENGT
Applicants: KORSNAES AB PUBL, NORDIN BENGT, KORSNAES AB (PUBL), NORDIN, BENGT
Application year: 1997
Main classification: B65D88
IPC codes: B65D5, B65D37, B65D88, E03B11