Patent Description:
Packaging containers are commonly used to hold goods, such as foodstuffs, during transport and storage in order to provide protection to the goods. However, packaging containers are not typically well sealed and so it is often necessary to provide an additional protective wrapper (e.g. a plastic bag) within the container to ensure that the goods cannot escape from the container and to prevent premature degradation of the goods. Examples of prior art packaging containers may be found in <CIT>, <CIT>, <CIT>, <CIT> and <CIT>.

The provision of an additional protective wrapper is a costly and inconvenient step during the packaging process.

The present disclosure thus seeks to address this issue by providing a packaging container which is, itself, sealed, such that goods do not require an additional protective wrapper. In accordance with a first aspect, there is described a blank for forming a packaging container, the blank comprising: a sheet defining an internal side and an external side of the packaging container; wherein the sheet comprises: a plurality of side panels separated from one another by side crease lines; a plurality of flaps, each one of the flaps extending from one of the side panels and being joined to the respective side panel by a flap crease line, each pair of adjacent flaps forming an inner flap and an outer flap; a sealant film disposed on the internal side of the sheet and having areas which are bonded to a portion of each one of the side panels and to a portion of each one of the flaps; wherein the sealant film comprises an unbonded area between the areas bonded to adjacent inner and outer flaps to allow the inner flap to first be folded inwards before the outer flap is folded onto the inner flap to form an end panel of the packaging container, with the sealant film forming a seal between the flaps, wherein the unbonded area extends across a portion of the outer flap; and wherein the sealant film is bonded to a triangular area of the outer flap which has its base located along the flap crease line and its apex located towards a free edge of the outer flap, wherein the base of the triangular bonded area is shorter than a length of the flap crease line; and the unbonded area extends across the outer flap by a distance which is greater than or equal to a length of the inner flap from the flap crease line so that the outer flap can lie directly against the inner flap.

The triangular area may be centred along the flap crease line of the outer flap.

The triangular area may be an isosceles triangle.

At least one crease line may be formed in the unbonded area of the sealant film.

The at least one crease line formed in the unbonded area of the sealant film may comprise a transverse crease line which extends across the sealant film and is formed in an opposite direction to the side crease lines.

The at least one crease line formed in the unbonded area of the sealant film may comprise a diagonal crease line which extends from a corner of the outer flap at the flap crease line to a centre of a free edge of the outer flap.

The sealant film may be bonded to the entire area of the inner flap.

The sheet may comprise in series a first side panel and a first flap joined to the first side panel, a second side panel and a second flap joined to the second side panel, a third side panel and a third flap joined to the third side panel, and a fourth side panel and a fourth flap joined to the fourth side panel; wherein the first and third flaps form outer flaps and the second and fourth flaps form inner flaps.

The sealant film may be a water-soluble synthetic polymer.

The sealant film may be polyvinyl alcohol.

In accordance with another aspect, there is provided a packaging container assembled from a blank as described above.

For a better understanding of the disclosure, and to show more clearly how aspects of the disclosure may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which:-.

<FIG> shows a blank <NUM> suitable for assembly into a packaging container or carton, such as a regular slotted container. The blank <NUM> is formed from a sheet <NUM> of cardboard (e.g. corrugated fibreboard or paperboard) or the like which defines an internal side of the finished carton (as seen in a <FIG>) and an external side of the finished carton (the opposing side, not visible in <FIG>). The blank <NUM> comprises a first side panel <NUM>, a second side panel <NUM>, a third side panel <NUM> and a fourth side panel <NUM>. The first side panel <NUM> is separated from the second side panel by a first side crease line <NUM>. The second side panel <NUM> is separated from the third side panel <NUM> by a second side crease line <NUM>. The third side panel <NUM> is separated from the fourth side panel <NUM> by a third side crease line <NUM>.

A first flap <NUM> extends from an end of the first side panel <NUM>. The first flap <NUM> is joined to the end of the first side panel <NUM> along a first flap crease line <NUM>. A second flap <NUM> extends from an end of the second side panel <NUM>. The second flap <NUM> is joined to the end of the second side panel <NUM> along a second flap crease line <NUM>. A third flap <NUM> extends from an end of the third side panel <NUM>. The third flap <NUM> is joined to the end of the third side panel <NUM> along a third flap crease line <NUM>. A fourth flap <NUM> extends from an end of the fourth side panel <NUM>. The fourth flap <NUM> is joined to the end of the fourth side panel <NUM> along a fourth flap crease line <NUM>.

As shown, a sealant film <NUM> (shown using a double-dashed border for clarity) is provided along an upper portion of the blank <NUM>. The sealant film <NUM> is rectangular in shape, and comprises areas which are glued or otherwise bonded to portions of the first, second, third and fourth side panels of the blank <NUM> and to portions of the first, second, third and fourth flaps, as depicted by the shaded area of <FIG>. In particular, the sealant film <NUM> is bonded to the first, second, third and fourth side panels <NUM>, <NUM>, <NUM>, <NUM> along a continuous strip extending a short distance (e.g. <NUM>) into the side panels and running along the flap crease lines <NUM>, <NUM>, <NUM>, <NUM>. Further, the sealant film <NUM> is bonded to a triangular area of each of the first and third flaps <NUM>, <NUM>, and to the entire area of the second and fourth flaps <NUM>, <NUM>. The triangular areas are the shape of isosceles triangles having their bases centred on the first and third flap crease lines <NUM>, <NUM> and tapering to an apex located at the centre of the free edge of the first and third flaps <NUM>, <NUM> (although in some examples, the apex may be spaced inwards of the free edge) distal from the first and third side panels <NUM>, <NUM> respectively. The base of each triangular bonded area is shorter than the length of the respective flap crease line <NUM>, <NUM> (or, in other words, the width of the first and third panels <NUM>, <NUM>). Consequently, an unbonded area of the sealant film <NUM> is formed between the areas bonded to adjacent flaps. The width W<NUM> of the unbonded area (measured parallel to the crease line <NUM>, <NUM>) is greater than or equal to the length L<NUM> of the second and fourth flaps <NUM>, <NUM>.

In the unbonded areas, the sealant film <NUM> is creased along diagonal crease lines <NUM>, <NUM>, <NUM>, <NUM>, as depicted in <FIG> by the dot-dash lines.

The diagonal crease lines <NUM>, <NUM> extend from the apex of the triangular bonded area on the first flap <NUM> to the bottom corners of the first flap <NUM> at the first flap crease line <NUM>. Similarly, the diagonal crease lines <NUM>, <NUM> extend from the apex of the triangular bonded area on the third flap <NUM> to the bottom corners of the first flap <NUM> at the third flap crease line <NUM>. As shown, the side crease lines <NUM>, <NUM>, <NUM> formed between the side panels <NUM>, <NUM>, <NUM>, <NUM> extend into the sealant film <NUM> to form additional transverse crease lines <NUM>, <NUM>, <NUM> that extend across the sealant film (parallel to the side crease lines <NUM>, <NUM>, <NUM>). However, the transverse crease lines are formed in the opposite direction (i.e. on the opposite side) to the side crease lines. The transverse crease lines <NUM>, <NUM>, <NUM> intersect the diagonal crease lines at the flap crease lines.

To assemble the blank <NUM> into a carton, the first and fourth side panels <NUM>, <NUM> are first affixed along their free edges by gluing, taping, stapling or any other method. In the example shown in <FIG>, a tab <NUM> is provided along the edge of the fourth side panel <NUM> which can be glued to the free edge of the first side panel <NUM>. A further side crease line may be formed between the first and fourth side panels <NUM>, <NUM>, for example, via the tab <NUM>. As part of this process or in a separate process, free ends of the sealant film <NUM> are joined to one another to form a continuous loop of sealant film <NUM> on the interior surface of the part-formed carton. A further transverse crease line may be formed between the ends of the sealant film <NUM> which extends parallel to the crease line between the first and fourth side panels <NUM>, <NUM>.

The first and third side panels <NUM>, <NUM> form a first pair of opposing sides of the carton and the second and fourth side panels <NUM>, <NUM> form a second pair of opposing sides of the carton. The flaps <NUM>, <NUM>, <NUM>, <NUM> are folded over to form an end panel of the carton. The second and fourth flaps <NUM>, <NUM> are folded inwards prior to the first and third flaps <NUM>, <NUM> such that the second and fourth flaps <NUM>, <NUM> form a pair of minor (or inner) flaps, whereas the first and third flaps <NUM>, <NUM> form a pair of major (or outer) flaps, with the minor flaps sitting internally of the major flaps. As the second and fourth flaps <NUM>, <NUM> are folded inwards, the unbonded area of the sealant film <NUM> also folds inwards about the diagonal crease lines <NUM>, <NUM>, <NUM>, <NUM> and away from the first and third flaps <NUM>, <NUM>. The inward movement of the second and fourth flaps <NUM>, <NUM> also draws the first and third flaps <NUM>, <NUM> inward via the sealant film <NUM>.

As described previously, the width W<NUM> of the unbonded area of sealant film <NUM> is greater than or equal to the length L<NUM> of the second and fourth flaps <NUM>, <NUM> such that the second and fourth flaps lie directly against the inner side of the first and third flaps <NUM>, <NUM> (i.e. between the first and third flaps <NUM>, <NUM> and the unbonded area of sealant film <NUM>) when the flaps are closed (i.e. when folded inwards such that they are perpendicular to the side panels). Accordingly, this process creates a 'board-to-board' contact between the exterior surfaces of the second and fourth flaps <NUM>, <NUM> and the interior, unbonded areas of the first and third flaps <NUM>, <NUM>, with the sealant film <NUM> folded into the interior of the carton.

The diagonal and/or transverse crease lines formed in the sealant film <NUM> are configured such that they encourage the sealant film <NUM> to fold inwards into the interior of the carton, as opposed to outwardly towards the exterior of the carton. In particular, as described previously, the transverse crease lines are formed in the opposite direction to the side crease lines.

It will be appreciated that, although not shown, a similar arrangement of flaps and sealant film is provided at the opposite ends of the side panels so as to form the other end panel of the carton, but this will not be described in detail.

A single sheet of sealant film <NUM> may seal both ends of the carton. In particular, as shown in <FIG>, the sealant film <NUM> may extend across the entire side panels and over both sets of flaps. Alternatively, a strip of sealant film <NUM> could be used to seal each end of the carton, with the sheet <NUM> of cardboard between the ends of the carton being coated (for example with Polyvinyl Alcohol (PVA/PVOH)).

The sealant film <NUM> creates an additional seal (which may be a hermetic seal) within the closure formed by the flaps. In particular, the sealant film <NUM> provides a seal between the flaps. This removes the need for perishable goods to be stored in a separate wrapper in the carton, as the carton essentially forms both the carton and wrapper in a single component.

The sealant film <NUM> may be formed from a water-soluble synthetic polymer, such as Polyvinyl Alcohol (PVA/PVOH). This may allow the carton to be recycled using standard techniques and without needing to first remove the sealant film <NUM>. Both low and high temperature PVAs could be used, with high temperature in this context meaning that the PVA only dissolves when in contact with water at a temperature over <NUM>. Alternative materials for the sealant film include polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polyactic acid (PLA), polyhydroxyalkanoate (PHA), polyvinyl chloride (PVC), polystyrene (PS) or any suitable polyolefin or polymer.

The invention is not limited to the specific embodiments disclosed above, and obvious modifications and substitutions will be apparent to those skilled in the art.

Claim 1:
A blank (<NUM>) for forming a packaging container, the blank comprising:
a sheet (<NUM>) defining an internal side and an external side of the packaging container;
wherein the sheet comprises:
a plurality of side panels (<NUM>, <NUM>, <NUM>, <NUM>) separated from one another by side crease lines (<NUM>, <NUM>, <NUM>);
a plurality of flaps (<NUM>, <NUM>, <NUM>, <NUM>), each one of the flaps extending from one of the side panels and being joined to the respective side panel by a flap crease line (<NUM>, <NUM>, <NUM>, <NUM>), each pair of adjacent flaps forming an inner flap (<NUM>, <NUM>) and an outer flap (<NUM>, <NUM>);
a sealant film (<NUM>) disposed on the internal side of the sheet and having areas which are bonded to a portion of each one of the side panels and to a portion of each one of the flaps;
wherein the sealant film comprises an unbonded area between the areas bonded to adjacent inner and outer flaps to allow the inner flap to first be folded inwards before the outer flap is folded onto the inner flap to form an end panel of the packaging container, with the sealant film forming a seal between the flaps, wherein the unbonded area extends across a portion of the outer flap; and
characterized in that:
the sealant film is bonded to a triangular area of the outer flap which has its base located along the flap crease line and its apex located towards a free edge of the outer flap, wherein the base of the triangular bonded area is shorter than a length of the flap crease line; and
the unbonded area extends across the outer flap by a distance (W<NUM>) which is greater than or equal to a length (L<NUM>) of the inner flap from the flap crease line so that the outer flap can lie directly against the inner flap.