WO2002074654A1

WO2002074654A1 - Bag for a bag-in-carton & a bag-in-carton incorporating same

Info

Publication number: WO2002074654A1
Application number: PCT/AU2002/000302
Authority: WO
Inventors: Rod Goullet
Original assignee: Prism Packaging Pty Ltd
Priority date: 2001-03-16
Filing date: 2002-03-15
Publication date: 2002-09-26
Also published as: AUPR376701A0; WO2002074654A9

Abstract

A bag (10) for a bag-in-carton (BIC) (12) includes two sheets (14) of flexible material, one overlying the other, with a fluid impervious joint (16) formed therebetween joining the sheets together. The joint (16) circumscribes a closed shape with rounded corners. The BIC (12) includes a carton (38) in the shape of a triangular prism having a base (40) and converging inclined sides (42) and (44). The bag (10) is disposed within the carton (38) in a manner so that the joint (16) lies in a plane that extends diagonally with respect to the base (40).

Description

Bag for a Bag-In-Carton & a Bag-In-Carton Incorporating Same

Field of the Invention The present invention relates to a bag or bladder for use in a bag-in-carton, for example of the type for holding water or wine, and to a bag-in-carton incorporating the bag or bladder.

Background of the Invention Packaging of the type known as bag-in-carton (BIC) is well known and has been commercially available for decades for holding liquids, typically foodstuffs/drinks, such as wine, fruit juices and water. A typical BIC comprises a six-sided closed carton or box made of cardboard in which is disposed a bag of substantially identical shape for holding a volume of liquid. The bag is made from plastics film, which may be in the form of a laminate and may include a metallised plastics layer. During manufacture, one or more sheets of the plastics film are welded to a shape conforming with an interior shape of the carton. This produces a number of seams where the film is welded together at corners of 90°. The exact number of seams formed depends on the specific manner of manufacture of the bag. However, the seams are orientated so as to coincide with interior corners or edges of the carton. In this way, the bag is fully supported by the outer carton, the outer carton providing the strength and rigidity to the total package, whilst the inner bag is in effect only required to form a means of waterproofing the interior of the carton. Narious types of taps or valves are welded or otherwise coupled to the bag and extend through the carton to allow for dispensing of the contents of the bag.

The present Applicant has developed a triangular prism shaped carton for a BIC. Surprisingly, the Applicant has discovered that incorporating the bag of conventional rectangular box BIC's in the triangular prism carton provides an unacceptably high failure rate. Narious tests have indicated that failure rates in excess of 30% when traditional bags are used in the prism carton. It is believed that the major reason for this failure is due to "flex-cracking" which occurs when the plastics film from which the bag is made is exposed to constant movement or bending. Since the conventional bag does not conform with the interior shape of the prism carton, the bag is not fully supported by the carton and there is thus an increased propensity for flex cracking to occur.

The immediately obvious solution to this would be to form the bag of an identical interior shape to the prism carton with welds at the corners of the bag to conform with the edges of the carton. However this is extremely difficult due to the practical difficulties in making plastics film conform to angles less than 90° while still providing sufficient strength to protect the contents of the bag.

Summary of the Invention

It is an object of the present invention to provide an alternate form of bag for a BIC which is less susceptible to failure than traditional bags irrespective of the shape of the carton in which it is housed.

According to a first aspect of the present invention there is provided a bag for a BIC, said bag including: two sheets of flexible material juxtaposed one overlying the other; a fluid impervious joint formed between said two sheets, said joint circumscribing a closed shape whereby a liquid containment volume is defined between said two sheets within said joint; and, a tap coupled to one of said sheets within said closed shape to provide fluid communication between said containment volume and an exterior of said bag.

Preferably said closed shape includes two opposed non-parallel lengths which extend substantially symmetrically about an intermediate plane.

Preferably said closed shape includes a third length extending perpendicular to said intermediate plane at an end of said first and second lengths which are most distant said intermediate plane. Preferably said closed shape includes a first arcuate portion which extends from one end of said third length to an adjacent end of said first length, and a second arcuate portion which extends from an opposite end of said third length to an adjacent end of said second length.

In one embodiment, a third arcuate portion extends between respective ends of said first and second lengths distant said third length. Thus, in this embodiment, said closed shape is in the configuration of a triangle with rounded corners.

In a further embodiment, said closed shape includes a fourth length extending parallel to said third length and joined with respective ends of said first and second lengths distant said third length, said fourth length being shorter than said third length and wherein said third and fourth lengths have respective mid-points which lie on said intermediate plane. In this embodiment, said closed shape further includes respective third and fourth arcuate portions which extend between respective opposite ends of said fourth length to adjacent ends of said first and second lengths. Thus, in this embodiment, said closed shape is in the configuration of a trapezoid with rounded corners.

According to a further aspect of the present invention there is provided a bag-in-carton including: a carton having a base and a plurality of sides extending from said base, said carton defining a closed space; and, a bag according to the first aspect of the present invention disposed within said space, said carton further provided with access means through which said tap can pass.

Preferably said bag is orientated within said carton so that said joint lies in a plane that extends substantially diagonally with respect to said base of said carton.

Preferably said carton is in the shape of a triangular prism with said base is in the shape of a quadrilateral said triangular prism having two opposed parallel sides in the shape of a triangle, and two further mutually opposed inclined sides extending between said triangular sides and meeting at an apex of said triangles.

Preferably said tap is disposed on said bag at a position which substantially coincides with the location of said access means, said access means being located on one of said inclined sides along a longitudinal axis of said inclined side and toward said base.

Brief Description of the Drawings

An embodiment of the present invention will now be described by way of example only with reference to the accompanying drawings wherein: Figure 1 is a plan view from the front of an unfilled bag in accordance with a first embodiment of the present invention;

Figure 2 is a plan view from the top of the bag depicted in Figure 1 when filled;

Figure 3 is a schematic representation of a carton incorporated in the present invention; Figure 4 is a plan view of a bag-in-carton in accordance with the present invention incorporating the bag depicted in Figures 1 and 2 and the carton depicted in Figure 3; and,

Figure 5 is a plan view from the front of a second embodiment of an unfilled bag in accordance with the present invention.

Detailed Description of Preferred Embodiments

Referring to the accompanying drawings, and in particular Figures 1, 2 and 4, a bag 10 for a BIC 12 includes two sheets 14 (only one being visible in Figure 1) of flexible material disposed one overlying the other with a fluid impervious joint 16 formed between and joining the two sheets together. The joint 16 circumscribes a closed shape so that a liquid containment volume is defined between the sheets 14 within the joint 16. A tap or valve 18 is coupled to one of the sheets 14 within the shape defined by the joint 16 to allow fluid communication between the liquid containment volume defined within the bag 10 and the exterior of the bag 10.

In the embodiment depicted in Figure 1, the closed shape defined by the joint 16 is in the configuration of a trapezoid, that is, a quadrilateral with two opposed non-parallel sides and two opposed parallel sides (although one of the parallel sides being shorter than the other), and with rounded corners. In the embodiment depicted in Figure 5, the shape defined by the joint 16 is in the configuration of a triangle with rounded corners.

More particularly, the shape defined by joint 16 in both embodiment as depicted in Figures 1 and 5, includes two opposes non-parallel (converging) straight lengths 20 and 22 that extend substantially symmetrically about an intermediate plane P. The joint 16 also includes a third substantially straight length 24 that extends perpendicular to the plane P at ends of the first and second lengths 20, 22 that are most distant from the plane P.

Again, in both embodiments, the joint includes a first arcuate portion 26 that extends between one end of the third length 24 and an adjacent end of the first length 20. A further arcuate portion 30 extends between an opposite end of the third length 24 and an adjacent end of the second length 22.

In the embodiment of the bag 10 depicted in Figure 5, the joint 16 includes a third arcuate portion 28 which extends between and joins the ends of lengths 20, 22 distant the third length 24. Thus, in essence, the joint 16 of the embodiment of the bag 10 depicted in Figure 5 is in the shape of a triangle with rounded sides, the lengths or portions 20, 22, 24, 26, 28 being formed integrally.

In the embodiment of the bag 10 depicted in Figure 1, the joint 16 includes a fourth substantially straight length 32 opposite the third straight length 24. The length 32 is shorter that the length 24 with the lengths 24 and 32 arranged so that their mid points lie along the intermediate plane P. Respective arcuate portions 34 and 36 extend between opposite ends of the fourth length 32 to the first and second lengths 22, 24 respectively. In this way, the bag 10 depicted in Figure 1 is in the shape of a trapezoid with rounded corners formed by the arcuate portions 26, 28, 34 and 36. The lengths and portions 20, 22, 24, 32, 26, 28, 34 and 36 of joint 16 are formed integrally.

As clearly depicted in Figures 1 and 5, the tap or valve 18 is offset from the centre of the shape defined by the joint 16. The reason for the offsetting of position of tap 18 is explained in greater detail below.

Figure 4 depicts a BIC 12 in accordance with an embodiment of this invention with Figure 3 depicting a carton 38 incorporated in the BIC 12. The carton 38 is in the shape of a triangular prism having a quadrilateral (rectangular) base 40, two opposed triangular sides 42, 44 and two inclined rectangular sides 46 and 48. The sides 46 and 48 extend from the base 40 and converge towards each other meeting at an edge 50 at the apex of the triangular prism. Respective edges 52 and 54 are formed between the base 40 and the inclined sides 46 and 48 respectively. As an inherent characteristic of the prism shape of the carton 38, the included angles at the edge 50, 52 and 54 are all less than 90°.

An access means in the form of a flap 56 is formed in the inclined side 48. The flap 56 is separately formed by cutting a line of perforations 58 in the side 48 which can be easily broken by hand. The flap 56 is located toward the base 40 and substantially centrally along a longitudinal axis of the side 48.

As is evident from Figure 4, the bag 10 when disposed within the carton 38 is orientated so that the joint 16 extends diagonally with respect to the base 40. Rounded corners are formed in the bag 10 adjacent the edges 52 and 54. There is thus no weld or joint in the bag that lies parallel with and seated in the edges 52 and 54 which would typically form the highest stress points within the bag and would be subject to the greatest amount of flexure and movement.

As shown in Figure 4, the tap 18 extends through the flap 56 on the side 48 of the carton 38. In order to be correctly located so as to extend from the flap 56, the tap 18 is offset from the centre of the shape defined by the joint 16.

The bag 10 can be made from any commercially available plastics film used in current BIC's. However to provide additional strength to the unsupported areas of the bag 10 in the regions of the edges 52 and 54, a specific plastics film can be used. This film comprises a laminated structure consisting of a layer of metallised polyester which is sandwiched between two layers of polyethylene and held together with two tie-layers. The overall gauge of this laminate is approximately 75 μm. Within this laminate is a further inner layer of flex resistant LLDPE of a 53 μm gauge.

The joint 16 is ideally made using a platen welding head providing a weld width of approximately 5mm. The platen in a flat welding plate in the shape of the joint 16 and produces a single continuous weld about the sheets of material 14.

Now that embodiments of the present invention have been described in detail it will be apparent to those skilled in the relevant arts that numerous modifications and variations may be made without departing from the basic inventive concepts. In particular, the term "sheet" is used to describe the layers 14 of material from which the bag 10 is made. Each sheet is by itself a single piece. However it is possible for each single piece to be made up of a plurality of smaller sheets or segments which are connected together to form a single sheet-like structure or article. Further, it is envisaged that the carton 38 can be made in the shape of other non-rectangular shapes such as for example square or triangular based pyramids. Also while the corners 26, 28, 30, 34, 36 of the bag 10 are described and illustrated in Figures 1 and 5 as rounded they may be formed as angled, i.e. straight edged corners.

All such modifications and variations are deemed to be within the scope of the present invention the nature of which is to be determined from the above description.

Claims

1. A bag for a BIC, said bag including: two sheets of flexible material juxtaposed one overlying the other; a fluid impervious joint formed between said two sheets, said joint circumscribing a closed shape whereby a liquid containment volume is defined between said two sheets within said joint; and, a tap coupled to one of said sheets within said closed shape to provide fluid communication between said containment volume and an exterior of said bag.

2. The bag according to claim 1 wherein said closed shape includes two opposed non-parallel lengths which extend substantially symmetrically about an intermediate plane.

3. The bag according to claim 2 wherein said closed shape includes a third length extending perpendicular to said intermediate plane at an end of said first and second lengths which are most distant said intermediate plane.

4. . The bag according to claim 3 wherein said closed shape includes a first arcuate portion which extends from one end of said third length to an adjacent end of said first length, and a second arcuate portion which extends from an opposite end of said third length to an adjacent end of said second length.

5. The bag according to claim 4 wherein a third arcuate portion extends between respective ends of said first and second lengths distant said third length.

6. The bag according to claim 5 wherein said closed shape includes a fourth length extending parallel to said third length and joined with respective ends of said first and second lengths distant said third length, said fourth length being shorter than said third length and wherein said third and fourth lengths have respective mid-points which lie on said intermediate plane.

7. A bag-in-carton including: a carton having a base and a plurality of sides extending from said base, said carton defining a closed space; and, a bag according to any one of claims 1-5 disposed within said space, said carton further provided with access means through which said tap can pass.

8. The bag-in-carton according to claim 7 wherein said bag is orientated within said carton so that said joint lies in a plane that extends substantially diagonally with respect to said base of said carton.

9. The bag-in-carton according to claim 8 wherein said carton is in the shape of a triangular prism with said base is in the shape of a quadrilateral said triangular prism having two opposed parallel sides in the shape of a triangle, and two further mutually opposed inclined sides extending between said triangular sides and meeting at an apex of said triangles.

10. The bag-in-carton according to claim 9 wherein said tap is disposed on said bag at a position which substantially coincides with the location of said access means, said access means being located on one of said inclined sides along a longitudinal axis of said inclined side and toward said base.