WO2005061215A1

WO2005061215A1 - Container blank and method of producing containers from these

Info

Publication number: WO2005061215A1
Application number: PCT/SE2004/001904
Authority: WO
Inventors: Bengt Jönsson; Lennart Friberg; Per Gustafsson
Original assignee: Eco Lean Research & Development A/S
Priority date: 2003-12-22
Filing date: 2004-12-17
Publication date: 2005-07-07
Also published as: RU2006126634A; EP1697117A1; CN1898076A; SE0303507D0; SE526271C2; RU2355618C2; SE0303507L

Abstract

The invention relates to a container blank (16) which comprises two flat panel portions (2) abutting each other, made of a flexible packing material. The panel portions (2) are each defined by a rim portion (4) along which the panel portions (2) are interconnected to define a closed compartment (6). The container blank (16) has a first end region (26) which is arranged to allow folding-in of at least one corner portion (8) of the container blank (16) to form a bottom surface (9) in connection with filling of the container blank (16) to provide a container (1). The invention also relates to a method of producing a container from said container blank.

Description

CONTAINER BLANK AND METHOD OF PRODUCING CONTAINERS FROM THESE

FIELD OF THE INVENTION The present invention relates to a container blank and a method of producing a container from such a container blank.

BACKGROUND ART A container of a flexible packing material for, in the first place, liquid contents is described, for example, in WO 99/41155 which discloses a container of a col- lapsible type, comprising three wall portions, of which two form opposite side walls and a third forms a bottom wall. The walls that are made of a plastic material are flexible and connected to each other to form a compartment whose volume depends on the relative position of the walls. This type of container is frequently used, above all for holding liquid products, such as foodstuffs and sanitary products. The bottom-forming wall can be arranged as a separate part which is inserted between and joined to two separate side walls to define a compartment. In this method, use is made of three separate webs of material that are brought together. The bottom-forming wall can also be arranged by a web of material being folded in the form of a W and joined to define a compartment. Joining occurs preferably by welding or gluing. Such a container is very advantageous since it is made of container blanks which till they are filled and sealed to form a container can be handled in the form of a web with a plurality of container blanks wound onto a roll. The container is relatively cheap, environment- friendly and user-friendly. No matter which of said alternatives is selected to arrange the bottom-forming wall, disadvantages may be experienced in the handling of the container blanks. In the portions where the bottom-forming wall is joined to the side walls, there are locally four layers of material, which means that a weld joint should locally com- prise all four layers of material, but in other areas only two layers of material. This causes problems in welding since the required power, pressure and holding time will be different seen along the connecting portion of the container blank. Moreover it may be difficult to provide a liquid-tight connection in the transition between portions with four and two layers of material respectively. When winding such a continuous web of blanks onto a roll, it also means that the roll will have a surface with different bearing capacities along its width. Measured at a point above a connecting portion between the bottom-forming wall and the side walls where four layers of material are joined, the thickness will in fact be twice the thickness measured at other points. Therefore there is a need for a different design of such a container, with retained function but produced from a container blank that eliminates problems of the above type .

OBJECTS OF THE PRESENT INVENTION The object of the present invention is to provide a container blank which can be arranged and supplied on a roll with uniform bearing capacity over its entire width. Another object is to provide a container blank which can be produced by using the same welding parameters along its entire connecting portion. A further object of the invention is to provide a container blank which obtains a reliable connection along its entire connecting portion. Yet another object is to provide a container blank which can be produced in existing machines, possibly involving a minor reconstruction. A further object is to provide a container blank which can be produced at a lower cost. One more object of the invention is to provide a method of producing a container from such a container blank.

SUMMARY OF THE INVENTION To achieve the above objects as well as further objects not stated, which will appear from the following description, the present invention relates to a container blank having the features as stated in claim 1. Preferred embodiments will be evident from claims 2-8. Moreover the invention concerns according to claim 9 a method of producing a container from such a container blank. Preferred embodiments of the method will be evident from claims 10-11. According to one aspect, the invention relates to a container blank which is characterised by two flat panel portions abutting each other, made of a flexible packing material and each defined by a rim portion, along which rim portions the panel portions are interconnected to define a closed compartment, the container blank having a first end region which is arranged to allow folding-in of at least one corner portion of the container blank to form a bottom surface in connection with filling of the container blank to provide a container. Such a container blank comprises two panel portions and thus has a double thickness of material over its entire surface. Connection by welding is thus facilitated since the same welding parameters can be used over the entire connecting portion. This means, in turn, that a welding tool can be made very simple. By the container blank comprising a uniform thickness of material over its entire surface, a very smooth winding of a continuous web of blanks is allowed, with succeeding container blanks, since the resulting roll will have a uniform bearing capacity over its entire width. A uniform bearing capacity is important to pre- vent buckling that can make correct positioning in packing machines difficult. A uniform bearing capacity further means that rolls of blanks can easily be stacked lying down. This is a considerable difference from con- tainer blanks according to prior-art technique which comprise portions with four layers of material as well as portions with two layers of material and which thus obtain a highly non-uniform bearing capacity. Moreover, a roll with a given diameter can accommodate roughly twice as many container blanks as a roll with the same diameter and holding conventional container blanks. The panel portions can be provided by a sheet folded once. The sheet, which preferably is a continuous web of material, is thus folded once (in the form of a V) , thereby forming a central fold. The sheet has rim portions, of which the fold constitutes one rim portion, which together define the panel portions. In other words, the two panel portions are arranged on either side of the fold. It should be mentioned that in terms of manufacture it will be considerably quicker to fold a sheet once than to fold a sheet in the form of a W. This results in a most important saving in costs. The panel portions can also be provided in the form of two separate sheets. The two sheets, which preferably consist of two separate webs of material that are brought together, are flat and abut each other. The sheets have rim portions which together define the panel portions. Said rim portions advantageously define at least one corner. In preparing the container blank to form a con- tainer, a folding operation in fact occurs to form the bottom surface of the container. Such a folding operation requires at least one corner portion to form a prismatic bottom surface. It is preferred for the container blank in its first end region to comprise creasing lines. Creasing lines facilitate folding while at the same time they provide a more distinct bottom surface, which in turn results in a more stable container which is also more aesthetically pleasing. It is also preferred for the compartment to be sterile. By the compartment being closed, sterility is retained until the compartment is opened before filling with the intended contents in connection with the preparation of the container blank to form a container. It is also preferred for the rim portion in a second end region to define a filling duct. The second end por- tion can be arranged, for example, at an end opposite to the first end region. The filling duct is intended to facilitate a filling operation. The filling duct can also be used as a pouring duct of an opened container. To ensure a continuous method of production of con- tainer blanks and also handling of container blanks, an individual container blank is advantageously arranged as one in a row of interconnected container blanks. Such a continuous web of blanks can be arranged in the form of a roll which is easy to handle and transport. Moreover the handling of the container blanks is simplified in the machine which is later used to prepare the container blanks to form completed containers. According to another aspect, the invention relates to a method of producing a container from a container blank having the features as stated in claims 1-8, comprising the steps of arranging an opening which makes the compartment communicate with the ambient air; through said opening, filling said compartment with contents, after which the opening is sealed; folding said corner portion which is positioned in the end region of the container blank to form a bottom surface; and fixing said folded corner portion. It is preferred for said folded corner portion to be fixed to said bottom surface. Fixing advantageously occurs by hot-melt adhesive. According to another aspect, a container is provided, which is characterised by two panel portions which are made of a flexible packing material and which are each defined by a rim portion along which the panel portions are interconnected, the panel portions, at least along part of said rim portions, being interconnected by sealing in a connecting portion, and the two panel portions, in a first section constituting an end region, being folded to form a bottom surface. Due to this solution, the total thickness of material where the rim portions of the panel portions are connected, is uniform over the entire connecting portion, which means that the risk of defects in the connection can be reduced or completely eliminated. If connection occurs by welding, the same parameters, such as holding time, power and pressure, can in fact be used over the entire connecting portion, which results in easy optimisation of both parameters and welding tools. By the number of layers of material in the connecting portion being the same over the surface of the entire container blank, and in the bottom-forming area of the container being halved compared with prior-art containers, roughly twice as many container blanks are accommodated on a roll of blanks. As a result, the number of interruptions in production for changing rolls can be halved. This reduces the unit cost of each container. Existing machines intended for production of the previous type of container can be used after a minor reconstruction. It is preferred for the panel portions in said first section to comprise creasing lines. The creasing lines contribute to giving the bottom surface a more distinct shape, which makes the container stand more steady on a base and also be more aesthetic. The creasing lines also facilitate the folding operation that is required to provide the bottom surface. The bottom surface is preferably rectangular. However, it will be appreciated that the bottom surface by its folded construction can be given the desired prisma- tic shape. By prismatic is here meant a two-dimensional shape with corners . It is preferred for the panel portions by their folding to form flaps, which flaps are fixed to said bottom surface. The container may further comprise a handle in the form of a gas-filled duct means. The handle is advantageously arranged along one side of the container and forms, by its gas filling, a bead which is comfortable to grasp while at the same time it provides stiffening to the container. Moreover the two panel portions can, in a second section, form opposite side walls, i.e. the side walls can be interconnected to define a closed bag-like com- partment with a folded bottom surface. The second section can also advantageously comprise an opening means, which for instance may consist of a tear initiation or an opening provided with a cap. Opening means in the form of a tear initiation is arranged most easily in a corner por- tion, thereby forming a spout-like means after tearing off. According to another aspect, the invention relates to a method of producing container blanks comprising the steps of providing two flat panel portions abutting each other, made of a flexible packing material and defined by rim portions, which rim portions form at least one corner of the panel portions; and defining a closed department by connecting the panel portions along said rim portions.

DESCRIPTION OF DRAWINGS The invention will in the following be described in more detail by way of example with reference to the accompanying drawings, which illustrate a currently preferred embodiment. Figs la and lb illustrate a container according to the invention, in a side view and a bottom view respectively. Fig. 2 is a schematic view of a container blank according to the present invention. Figs 3a-3d illustrate schematically the steps of producing a container blank according to the invention. Figs 4a-4d illustrates schematically the steps of producing a container from a container blank.

TECHNICAL DESCRIPTION Figs la and lb illustrate a container 1 according to the present invention. The container 1 is shown in an unopened state and filled with liquid contents. The container 1 is particularly intended for liquid food products, such as milk, water, juice or wine. Of course, the container 1 can also be used for non-liquid products and products other than foods. The container 1 is of a collapsible type, i.e. its volume depends on the relative position of its side walls, which means that the volume of the compartment depends on its degree of filling. The container 1 com- prises two flexible panel portions 2 which form side walls 3 of the container. Each panel portion 2 is defined by rim portions 4. The panel portions are interconnected in connecting portions 5 along said rim portion 4 to define a closed compartment 6. The panel portions 2 are preferably interconnected by welding in the connecting portions 5. The two panel portions 2 form a first section 7 which constitutes an end region 26. In this end region 26, which in the shown embodiment constitutes a lower part of the container 1, two opposite corner portions 8 of the two panel portions 2 are folded transversely to the connecting portion 5, thereby forming a bottom surface 9 in the container 1. The bottom surface 9 extends in a plane transversely to the longitudinal axis L of the container 1. The bottom surface 9 formed by folding can, according to type of material and thickness, be defined by creasing lines 10 as shown. The creasing lines 10 are advantageously also arranged to define the flaps 11 which are formed by folding of the corner portions 8. The flaps 11 are folded towards the bottom surface 9 and fixed to the same, suitably by hot-melt adhesive. Of course, the flaps 11 can just as well be folded outwards towards the side walls 3 of the container 1 and be fixed thereto, or be oriented in some other manner. The container 1 shown in Figs la and lb further has an end region 14 in a second section 12. In this second end region 14, the container 1 has a corner portion 15 which is adapted to be separated, for example, by cutting or tearing-off to open the container 1. This results in a spout being formed. In the embodiment illustrated, the panel portions 2 in the second section 12 form opposite side walls which are interconnected along their periphery. The container 1 has a gas-filled duct means 13 in the connecting portion 5 along one side of the second section 12. The gas-filled means 13 is formed as a handle-forming bead which is comfortable to grasp. The gas-filled duct means 13 also gives the container 1 a stiffening effect. The container 1 is preferably made of a material comprising a filler of mineral material and a binder of polyolefin material. The mineral material is advantageously chalk (calcium carbonate) . A container 1 as described above is produced from a container blank 16 which will be described in detail below with reference to Figs 2 and 3a-3d. The container blank 16 may comprise two flat panel portions 2 which abut each other and are arranged by bringing together two separate webs of material 17 or sheets, see Fig. 3a, or alternatively comprise two flat panel portions 2 or sheets which abut each other and are obtained by folding a web of material 17 once (folding in the form of a V) , see Fig. 3a'. The resulting fold 18 thus forms a rim portion 4. With reference to Fig. lb, the fold 18 is advan- tageously arranged in the first end region 26 of the container blank 16, i.e. so that the fold 18 in a completed container 1 is arranged on the bottom surface 9 of the container . The two panel portions 2 are thus interconnected along their rim portions 4 to define a closed compartment 6 where the rim portions • 4 outwardly define the contour of the container blank 16. The connection can also take place either by a combination of folding and welding, or by welding only. Welding is a preferred method of joining since it is quick and easy. However, it will be appreciated that, for instance, also gluing can be used. With reference to Fig. 2, the two panel portions 2 define by their rim portions 4 a practically rectangular geometry in the shown container blank 16, which geometry has a front boundary line 19, a rear boundary line 20, an upper boundary line 21 and a lower boundary line 22. The rear boundary line 20, i.e. the boundary line on the side that is adapted to form a gripping surface in a completed container 1, defines together with an intermediate boundary line 23 a duct means 13' intended for gas filling. The front boundary line 19 is connected to the rear boundary line 20 by the upper boundary line 21 and the lower boundary line 22 respectively. The upper boundary line 21 is adapted to be wholly or partly separated before filling of the container blank 16 in order to be formed once more for sealing after filling. The transition between the front boundary line 19 and the upper boundary line 21 forms the corner portion 15 which is adapted to be separated for opening a container 1 so as to form a spout. In order to facilitate separation, a tear initiation (not shown) can be arranged in the container blank 16. The lower boundary line 22 and the intermediate lower boundary line 24 define together with the lower parts of the front 19 and the rear 20 boundary line respectively an area which, by folding, is adapted to form the bottom surface 9 of a completed container 1. The bottom surface 9 has previously been described in connection with the description of the container 1 and is distinctly shown in Fig. lb. As is evident from Fig. 2, intersections A, B, C, D between the rear 20, upper 21, front 19 and intermediate lower boundary line 24 constitute corner points in a parallelogram having an angle of inclination α relative to a longitudinal axis L of the container blank 16. In this parallelogram, the front boundary line 19 forms an angle that is acute towards the intermediate lower boundary line 24. The front boundary line 19, the upper boundary line 21, the intermediate boundary line 23 and the intermediate lower boundary line 24 thus define a central portion 25 of the compartment 6 which has the shape of a substantially symmetric truncated cone. The angle α in combination with the truncated conical shape compensates for any tendency of a container 1 made from the container blank 16 to tilt forwards due to displace- ment of the centre of gravity. By the tilting tendency being reduced, also any risk of creasing along the front boundary line 19 of the container 1 is reduced, see Fig. la. The chosen angle α depends on factors such as height, width and material rigidity of the container, and it is thus difficult to indicate a value. Another important factor for the choice of angle is the cross- sectional geometry of the compartment 6 which is expanded by the panel portions 2 and the bottom surface 9, respectively, in the filled state of the container 1. In order to facilitate said folding to provide the bottom surface 9 as well as to reduce the material stress caused by the folding, the first end region 26 may comprise creasing lines 10. The creasing lines 10 can be arranged in some or all lines intended for folding. The container blank 16 shown in Fig. 2 is intended for production of a container 1 with a rectangular bottom surface 9. In the following a method for producing a container blank 16 will be described with reference to Figs 3a-d. Starting in Fig. 3d, container blanks are produced preferably in the form of a continuous web of blanks 27 comprising a large number of container blanks 16 which are arranged side by side and wound onto a roll 28 for further handling. The container blanks 16 can, of course, also be produced one by one from a material in the form of sheets . The continuous web of blanks 27 can be produced either by two separate webs of material 17, as shown in Fig. 3a, being brought together to form two flat webs of material abutting each other, or, as shown in Fig. 3a', by folding a continuous web of material 17 once to form a central longitudinal fold 18. The web of blanks 27 is passed to a station, see Fig. 3b, at which a welding operation 29, or alternatively a gluing operation, connects the two webs of material 17 to each other. The connection occurs along a geometry corresponding to the outer contour, i.e. the rim portions 4, of the container blank 16, which means that each container blank 16 will comprise two flat panel portions 2 abutting each other and defined by rim portions 4. The rim portions 4 will by the welding define a closed compartment 6 of each container blank 16. This means that the compartment 6 can already be made internally sterile in the production of the container blank 16 and that the sterility is retained until the container blanks 16 are opened before filling to be prepared to form a container 1. The rim portions 4 give the container blank 16 such a contour that at least one corner portion 8 is formed. In fact, at least one corner portion 8 is required for folding a container blank 16 to form said bottom sur- face 9. With reference to Fig. 3c, creasing lines 10 are advantageously arranged in the panel portions along some or all folding lines which are arranged in the subsequent folding to form the bottom surface 9. In Fig. 3c, the creasing lines 10 are formed in a separate operation after welding. However, it will be appreciated that the creasing lines 10 can be arranged before or after welding, or alternatively in the same tool as used for welding. The creasing lines can even be arranged in advance in the web or webs of material that is/are used for producing the container blanks. The operation can also be left out. With reference to Fig. 3d, the now completed continuous web of blanks 27 is wound onto a roll 28. By each container blank 16 merely comprising two layers of material, the roll 28 will have the same bearing capacity over its entire width. It will, however, be appreciated that the thickness of material locally over the welded rim portions will be somewhat smaller, but that this difference is inevitable and negligible. An even bearing capacity means that the rolls 28 can be stacked without problems. In connection with winding of the web of blanks onto a roll, excess material, i.e. material outside the rim portions, can be cut away by punching. Of course, punching can also take place earlier or in connection with the preparation to form containers 1. The completed web of blanks 27 can, of course, also be passed directly to a machine for immediate production of containers instead of being wound onto a roll 28. With reference to Figs 4a-4d, the method of pro- ducing a container 1 from the above-described container blank 16 will now be described. With reference to Fig. 4a, the web of blanks 27 with container blanks 16 is passed to a sterile room 30, in which the container blank 16 is opened, preferably along the upper boundary line 21, which makes the compartment 6 communicate with the ambient air. Subsequently a filling nozzle 31 is inserted through the opening, after which the container blank 16 is filled with the intended contents, and finally sealed once more. Said opening can be arranged in a filling duct (not shown) in the second end region 14 of the container blank. In connection with this operation, the duct means 13' intended for gas filling is advantageously filled with gas through a schematically drawn nozzle 32. After filling, the container blank 16 will resemble a filled bag 33, see Fig. 4c. Depending on how the machine used is constructed, it should be mentioned that, before or after filling, it may have separated the individual container blanks, in which case they are handled one by one. It is preferred for separation to take place before filling. The filled bag 33 is passed to a new tool (not shown) in which the bag is initially compressed in order to press away contents from the first end region 26 which in the completed state of the container is adapted to form the bottom surface 9. Then the corner portions 8 are folded to form the bottom surface 9. The corner portions 8 will thus form flaps 11 which can be folded either under the bottom surface 9, or up towards the side walls 3 of the container 1. To facilitate folding and for the bottom surface 9 to obtain a more distinct geometry, it is preferred for the container blank 16 to comprise the previously described creasing lines 10. Finally, the folded flaps 11 are fixed to, for instance as shown, the bottom surface 9. The flaps can also be fixed in some other way or to another surface. Fixing suitably occurs by means of hot-melt adhesive. By the steps described above, a completed container 1 has now been obtained. If the container blank 16 comprises the above- mentioned additional duct means (not illustrated) which are integrated in double wall panel portions 2, they are filled with gas suitably in connection with the operation in which the compartment is filled with its contents or alternatively sealed once more after completed filling, or in connection with gas filling of a possibly handle- forming duct means 13 ' . It will be appreciated that said folding of the bottom surface 9 can take place before the container blank 16 has been filled with the intended contents. The advantage of folding in the filled state of the container blank 16 is, however, that its side walls 3 are separated by the contents, thus facilitating folding. A container blank and methods of producing a container from the same have been described above. It will be appreciated that the present invention is not limited to the shown embodiments and method steps . Several modi- fications and variants are conceivable, and the invention is consequently defined exclusively by the appended claims .

Claims

1 . A container blank, c h a r a c t e r i s e d by two flat panel portions (2) abutting each other, made of a flexible packing material and each defined by a rim portion (4), along which rim portions the panel portions (2) are interconnected to define a closed compartment (6), the container blank (16) having a first end region (26) which is arranged to allow folding-in of at least one corner portion (8) of the container blank (16) to form a bottom surface (9) in connection with filling of the container blank (16) to provide a container (1) .

2. A container blank as claimed in claim 1, in which the panel portions (2) are provided by a sheet folded once .

3. A container blank as claimed in claim 1, in which the panel portions (2) are provided in the form of two separate sheets.

4. A container blank as claimed in claim 1, in which said rim portions (4) define at least one corner.

5. A container blank as claimed in claim 1, in which said first end region (26) comprises creasing lines (10) .

6. A container blank as claimed in claim 1, in which the compartment (6) is sterile.

7. A container blank as claimed in claim 1, in which the rim portion (4) in a second end region (14) defines a filling duct.

8. A container blank as claimed in claim 1, which is arranged as one in a row of interconnected container blanks (16) to form a roll (28) of container blanks.

9. A method of producing a container from a container blank (16) as claimed in any one of claims 1-8, comprising the steps of arranging an opening which makes the compartment (6) communicate with the ambient air; through said opening, filling said compartment (6) with contents, after which the opening is sealed; folding said corner portion (8) which is positioned in the end region (26) of the container blank (16) to form a bottom surface (9); and fixing said folded corner portion (8).

10. A method as claimed in claim 9, in which said folded corner portion (8) is fixed to said bottom surface (9) .

11. A method as claimed in claim 9, in which said folded corner portion (8) is fixed by hot-melt adhesive,