GB2260968A

GB2260968A - Lined cartons

Info

Publication number: GB2260968A
Application number: GB9212761A
Authority: GB
Inventors: Paul Robert Booth; Alan Mackracken
Original assignee: Boxfoldia Ltd
Current assignee: Boxfoldia Ltd
Priority date: 1991-06-18
Filing date: 1992-06-16
Publication date: 1993-05-05
Also published as: GB9212761D0; GB9113125D0

Abstract

In a carton of the kind in which a body is defined by side walls (25-28) fold ably connected to a base (24) and secured together in adjacent pairs to form the corners of the carton by means of a respective attachment flap (30) on one of said wail panels in overlapping relation with an adjacent one of said panels, a lining (40) is provided which extends continuously across at least such corners of the carton, the lining being secured to the blank from which the carton is formed and before it is folded to form the canton. <IMAGE>

Description

Title: "Carton and method of manufacture thereof" Description of the Invention This invention relates to cartons and to a method of manufacture of cartons which are formed by suitably folding substantially flat blanks. Such blanks are formed with various creases, fold lines, perforations, slits and the like to define the carton walls, flaps and tabs as required by the specific design of carton, all by well known techniques.

A blank is usually manipulated by various machines to effect transition to an erect condition wherein it forms the carton but known cartons which are formed in this way suffer from the problem that the products packaged therein, or components thereof, such as liquids, grease or the like contained in the cartons when they are in use, for example to contain food, tend to penetrate into and through the carton material, and liquids or greases particularly enter the carton material through exposed edges at the corners at which the walls of each carton are secured to one another to hold the carton in an erect condition. Heat may also be lost at an undesirable rate in some cases.

These problems can be mitigated by utilising cartons having gusseted corners so that there are no exposed edges of material and/or by employing a carton forming material which is faced with a lamina having the requisite barrier properties. However, the design of such gusseted corners imposes certain limitations on the thickness of material which can be used relative to the size of the blank, and laminated materials are costly to use.

The carton and the method of manufacturing a carton as disclosed herein seeks to overcome or reduce the problems associated with known cartons as recited above.

According to a first aspect of the invention we provide a flat blank of material for forming into a carton by folding, the blank comprising two panels which, when the blank is folded into an erect condition, comprise adjacent side walls of a carton body, at least one of said side wall panels having an attachment flap formed effectively as an extension of said one panel, said attachment flap being separated from the adjacent side wall panel by a discontinuity in the material of which the blank is formed, the attachment flap being adapted to overlap and be secured to the adjacent side wall panel to form a joint at a corner defined by said two side wall panels when the blank is erected to form a carton, the blank having secured thereto a lining which extends across the discontinuity between said attachment flap and the adjacent side wall panel.

Part of the lining in the vicinity of the discontinuity may be free to move relative to the panels of the blank adjacent to the discontinuity, for example by virtue of the lining not being secured to the blank in the vicinity of the discontinuity and/or by virtue of the discontinuity being formed as gap whereby the proximal edges of the adjacent panels of the blank are spaced apart.

The lining may be secured to the panels of the blank by means of adhesive or wax or the use of a heat sealable material.

The configuration of the blank may be such that proximal edges of the attachment flap and of the adjacent wall panel to which it is to be secured to form a corner in the erect container, are separated from one another by a slit or a gap and the lining overlies and spans the slit or gap throughout at least part of the length of the proximal edges.

The lining may comprise a gusset which lines the joint at a corner of the container and distinct and separate gussets may be provided at respective joints, each gusset preferably comprising a lining secured to a respective pair of adjacent side walls and to the base panel such that each gusset lines a corner of the container.

The container may comprise more than two side walls at the edges of a base panel and the lining may be secured to at least one of the side walls and preferably the lining is secured to each of the side walls such that where there are more than two side walls it lines the joints between each pair of adjacent side walls.

Preferably the lining is attached to the attachment flap by which the adjacent side walls are attached to one another.

The lining may comprise at least one sheet of lining material.

The or each sheet of lining material may have one or more of grease barrier, moisture barrier, heat barrier or other properties which protect or enhance the container or the product to be packaged therein, or assist for example in the cooking of a food product contained therein.

Preferably the or each lining is provided on an inside surface of the container and in this case the above mentioned proximal edges are separated by a gap. Alternatively, or additionally, however, such lining could be provided on the outside of the container. Moreover, if desired, a lining having a first barrier property may be secured to the container and one or more further linings having the same or other barrier properties may also be secured to the container, any or all of such linings being secured to an outside or to the inside surface of the container. In the case of such multiple linings, each lining may cover the same or different portions of the blank.

The or each lining may be secured to the container by means of adhesive or wax, or the use of a heat sealable material.

The lining material may be susceptible of folding or creasing and preferably the arrangement is such that the lining material undergoes folding or creasing during transition of the carton between the blank and erect conditions without the need for mechanical guidance by external means.

The corners may be formed at bases of said side walls.

The carton may be tapered away from a mouth thereof, the gussets in the lining being so formed as to permit nesting of a further similar carton therein.

According to a second aspect of the invention we provide a method of forming a blank according to the first aspect of the invention comprising the steps of: cutting said blank from a web of relatively rigid material, forming in said first blank fold lines, creases, perforations, slits as necessary to facilitate subsequent folding of the blank to form a carton, cutting a liner from a web of lining material, and securing said liner to said blank at least in a region thereof which forms a corner between adjacent side walls and in such a manner that in part said liner is free to move relative to said blank.

According to a further aspect of the invention we provide a method of forming a carton from a blank according to the invention comprising the steps of folding the blank into the shape of the carton and allowing a portion of the lining to form a continuous gusset across the joint and securing the carton in its erect condition.

The invention will now be described by way of example with reference to the accompanying drawings in which: FIGURE 1 shows one embodiment of blank for forming into a carton and according to the invention; FIGURE 2 shows a detail of a corner of the blank illustrating securement of a lining material; FIGURE 3 shows the corner which is illustrated in Figure 2 but in a partially folded condition; and FIGURE 4 illustrates the corner as illustrated in Figures 2 and 3 in a completely folded condition so as partially to form the configuration of an erected carton.

Referring to the drawings, in Figure 1 the blank 20 comprises a relatively rigid material such as a board material which is foldable to provide a carton with an integral lid. The blank 20 comprises a body-forming part 21, a lidforming part 22. A closure tab 23 is provided on the body-forming part for engagement with appropriate formations on the lid-forming part blank 22 to permit of securing the lid in a closed condition in the erected carton, although this does not form part of the present invention and alternative securing arrangements may be provided. It will be understood from the foregoing description and from the following description that the invention is not restricted to lidded cartons and where provided the lid need not be integrally formed with the carton body.

In accordance with the invention, a piece of lining material 40 partially overlies and is secured to the body-forming part 21, the lining material comprising a material having grease barrier, moisture barrier or heat barrier or other properties which may serve to protect or enhance the container, or the product to be packed therein, or to assist in some treatment of such product in the container, for example the cooking of a food product, in addition to providing a physical barrier to the passage of liquid, semi-liquid or solid matter therethrough.

For example the lining material might comprise barrier paper, plastics film, aluminium, foil or the like or combinations thereof.

The body part 21 is formed with fold lines, creases, perforations or slits, collectively denoted by the numeral 23 which serve to define the boundaries between various carton walls, flaps and tabs in conventional manner.

In the embodiment which is shown in Figures 1 to 4 the container to be formed includes a rectangular base 24 and upstanding walls 25, 26, 27, 28.

The walls 27, 28 are provided with attachment flaps 30 at opposite ends thereof whereby adjacent pairs of side walls may be attached to one another when the blank is folded from its flat condition to its erect condition to define the carton body.

However, the carton body need not be of rectangular shape and it will be understood from the foregoing and from the following descriptions that the carton could comprise as few as two side walls (which are curved) or three or more side walls; the carton could be essentially wedge shaped when erected so as to have no distinct base.

An adhesive material 31 is applied to the blank to secure the lining 40 in a manner which permits of folding of the blank from a flat condition to an erect condition and the retention of the liner in place when the blank is in an erect condition.

In the illustrated embodiment discrete patches of adhesive material are applied to the walls but additionally if required adhesive may be applied to the base.

Turning now to Figure 2 a detail of one of the corners of the bodyforming part 21 is shown in which a patch 34 of adhesive is applied to the wall 28 adjacent a fold line 18 between the wall 28 and the attachment flap 30 thus ensuring that attachment of the lining material 40 to the blank 20 in this region conforms closely to the fold line 18 which will form part of a corner of the container when the blank is folded into an erect condition. This particularly facilitates the nesting of the formed cartons without hindrance from the liners, where, as in the illustrated embodiment, the walls diverge upwardly for this purpose.A patch 36 of adhesive however is positioned slightly away from the end edge 15 of the adjacent wall 26 so that when the container is erected from the blank folding of the lining 40 may occur at an edge of the adhesive patch 36 as indicated by the numeral 17 in Figure 3.

A further patch 35 of adhesive material applied to the attachment flap 30 whereby the lining material is secured at the corner thereof.

It will be observed that, in the flat blank, the lining 40 overlies and spans a gap which exists between the end edge 15 of the wall 26 and an edge 19 of the flap 30. When the blank is folded into an erect condition folding or creasing of the lining 40 in this region occurs without loss of the structural integrity of the lining so that the lining 40 forms a gusset at the corner defined between the walls.

The body-forming part 21 is folded in the manner indicated in Figures 2 to 4 by folding the walls 26 and 28 relative to the base 24 along the corresponding edges 14 and 13 of the base and by folding the attachment flap 30 inwardly about the end 18 of the wall 28. The edge 19 of the attachment flap 30 is angled so as to cause folding of the lining 40 as indicated in Figure 3 and so as to permit of the attachment flap 30 overlying a marginal region of the adjacent wall 26. The attachment flap 30 can then be secured in this position relative to the wall 26 by means of adhesive or wax or a heat sealable material 11 applied to either or both of the attachment flap 30 or the wall 26. When the adhesive is set the adjoining walls 26 and 28 are secured in erected condition relative to one another and the lining 40 forms a gusset between these side walls.

It will be noted that as shown in Figure 4, the lining material is wrapped around the cut edge 19 of the attachment flap and forms a gusset 12 between the flap 30 and the adjacent wall 26, whilst the edge of the lining material in the gusset 12 formed in the corner is not at any point nearer to the base 24 of the container than the edge of the portion of the liner where it extends along the wall panel. This ensures that the integrity of the protective properties of the lining material are maintained to substantially the same height all around the walls of the container.

It will be appreciated that by a modification of this arrangement the attachment flap 30 could be adhered to an outside surface of the adjacent wall 26 rather than to an inside surface thereof. In that case there need not be a gap between the edges 19 and 15, the flap 30 and panel 26 being separated by only a slit, and the requisite folding of the external liner to form a gusset can be achieved by arranging the adhesive in such a manner that the liner can peel back from the attachment flap and fold around the edge 15 as the flap 30 is brought into overlapping relation with the panel 26 Likewise, whilst the lining material in the illustrated embodiment is disposed internally of the erected carton, it could be arranged on the container, or both internal and external linings could be provided.

It will also be appreciated that whilst the inventive features disclosed herein are shown as applied to a carton having a tapered configuration when erected and which, by virtue of the tapered configuration may readily nest within another carton to form a stack of such cartons, the invention is not limited in its applicability to such tapered cartons.

Furthermore it will be understood that since it is the regions where joints occur between different parts of the carton which are most prone to leakage of contents or heat from the carton it may be desirable in certain instances to provide lining materials such as have been disclosed herein only in said joint regions and/or in regions of the carton at which fold lines, creases, perforations, slits or the like are provided. Thus instead of employing a single liner as illustrated, individual pieces of lining material may be provided at the corners only.

The features disclosed in the foregoing description, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

CLAIMS:

1. A flat blank of material for forming into a carton by folding the blank and comprising two panels which, when the blank is folded into an erect condition, comprise adjacent side walls of a carton body, at least one of said side wall panels having an attachment flap formed effectively as an extension of said one panel, said attachment flap being separated from the adjacent side wall panel by a discontinuity in the material of which the blank is formed, the attachment flap being adapted to overlap and be secured to the adjacent side wall panel to form a joint at a corner defined by said two side wall panels when the blank is erected to form a carton, the blank having secured thereto a lining which extends across the discontinuity between said attachment flap and the adjacent side wall panel.

2. A blank according to Claim 1 wherein part of the lining in the vicinity of the discontinuity is free to move relative to the panels of the blank adjacent to the discontinuity.

3. A blank according to Claim 2 wherein the discontinuity comprises a gap between the proximal edges of the attachment flap and the adjacent wall panel to which it is to be secured.

4. A blank according to Claim 3 wherein the lining is attached to the blank at a position adjacent to an end edge of said one panel at which said attachment flap is provided.

5. A blank according to Claim 3 or Claim 4 wherein said lining is attached to said attachment flap.

6. A blank according to any one of Claims 2 to 5 wherein said lining is attached to said adjacent side wall panel at a position spaced from an end edge thereof at which said attachment flap overlaps said adjacent side wall panel when the blank is erected.

7. A blank according to Claim 2 wherein the discontinuity comprises a slit which defines the proximal edges of the attachment flap and of the adjacent wall panel.

8. A blank according to any one of the preceding claims wherein the lining comprises a single piece of lining material which extends over all of the panels which form the side walls of the carton when the blank is erected.

9. A blank according to any one of Claims 1 to 7 wherein said lining comprises a plurality of pieces of lining material secured to said blank in respective regions thereof which define proximal ends of adjacent side wall panels.

10. A blank according to any one of the preceding claims wherein said lining is secured to the face of the blank which forms the interior face of the carton formed from the blank.

11. A blank according to any one of the preceding claims wherein the lining is attached to the face of the blank which forms the exterior face of the carton formed from the blank.

12. A blank according to any one of the preceding claims wherein the lining is secured to the blank by means of adhesive, or wax, or the use of a heat sealable material.

13. A blank according to any one of the preceding claims wherein the or each liner comprises a material having one or more of grease barrier, moisture barrier, heat barrier or other properties which protect or enhance the container

14. A carton formed from a blank according to any one of the preceding claims.

15. A carton according to Claim 14 wherein said lining is arranged internally of said carton, said attachment flap is secured to the inner surface of said adjacent wall panel, and said lining is folded over a free edge of said attachment flap so as to form a gusset lying between said attachment flap and said adjacent panel.

16. A carton according to Claim 15 wherein the edge of the lining in said gusset is not at any point below the level of the edge of the lining where it extends along said adjacent wall panels.

17. A method of forming a blank according to any one of Claims 1 to 13 comprising the steps of: cutting said blank from a web of relatively rigid material, forming in said first blank fold lines, creases, perforations, slits as necessary to facilitate subsequent folding of the blank to form a carton, cutting a liner from a web of lining material, and securing said liner to said blank at least in a region thereof which forms a corner between adjacent side walls and in such a manner that in part said liner is free to move relative to said blank.

18. A method of forming a carton from a blank according to any one of Claims 1 to 13 comprising the steps of folding the blank into the shape of the carton and allowing a portion of the lining to form a continuous gusset across the joint and securing the carton in its erect condition.

19. A blank comprising a body-forming part and lining substantially as hereinbefore described with reference to and as shown in Figure 1 of the accompanying drawings.

20. A carton comprising a body provided with a liner and having at least one corner formed substantially as hereinbefore described with reference to and as shown in Figure 4 of the accompanying drawings.

21. A method of forming the corner of a carton body substantially as hereinbefore described with reference to and as illustrated in Figures 2 to 4 of the accompanying drawings.