GB2356625A

GB2356625A - Carton

Info

Publication number: GB2356625A
Application number: GB0025396A
Authority: GB
Inventors: Louisa Helen Jeffrey
Original assignee: M Y CARTONS Ltd
Current assignee: M Y CARTONS Ltd
Priority date: 1999-10-22
Filing date: 2000-10-17
Publication date: 2001-05-30
Also published as: GB0025396D0; GB9925001D0

Description

2356625 Carton The invention to which this application relates is a carton

formed of board material and of a type used to contain a substance such as, but not necessarily exclusively, a foodstuff. Yet further, the carton which is the subject of the application is provided to allow a foodstuff which may be or may include a liquid to be carried in the carton and which prevents or minimises spillage or seepage of the liquid from the carton.

The use of cartons formed from board material and the coating of the same with material to repel liquid is well known in the trade and the use of this type of carton to carry foodstuffs is also known. However,, with board material cartons it is commonly the case that the foodstuff held in the carton is either a solid foodstuff or is frozen so as to be provided and stored in a solid form. One of the reasons for this is that as the carton is formed from sheet material, when the same is formed into a carton, there is a requirement for portions of the material to be folded. The fold lines can act as channels which encourage the capillary flow of liquids and which can cause the liquid to pass along the fold line and leak from the carton which is obviously undesirable. For this reason foodstuffs, which include a liquid content, such as chilled ready cooked meals are conventionally only contained within trays made from plastics material due to the problems with leakage with board material cartons.

Another problem with the use of cartons and liquid foodstuffs is that when the cartons are formed, a heat sealing technique can be used which involves the blowing of hot air onto the portions of the sheet material to be adhered to form the carton. These portions are typically coated with a heat sealing material which when activated by heat causes the portions to be sealed together. However it has been 2 found that the application of the hot air can cause degradation in the coating on the board material such that the liquid repellence of the board material is reduced. While this is not a problem when the cartons are used to contain solid or frozen substances, when a liquid is contained in the carton this can cause the liquid to ingress into the board material over a period of time.

In a first aspect of the invention there is provided a carton formed from a blank of sheet board material, said carton provided for the containment of a substance and said material foldable to an erect condition to form the carton by attaching together sets of portions of the materiaL and at least some of the portions are coated with heat sealable material which when heat is applied thereto activates adherence of the portions and wherein a set of portions comprises at least a first portion, a second portion and a third portion and when the carton is formed the second portion is attached to the first portion and the third portion is attached to the second portion and/or first portion.

In one embodiment the third portion is attached to the first and second portions.

Typically the carton is erected with a number of spaced locations of said sets of portions. In one embodiment the said locations are at each of the corners of the carton and especially when the carton is in a tray form in which the side walls are relatively small compared to the area of the carton base.

In an alternative embodiment of the carton a set of portions are located at each corner of the side and end walls of the carton.

It is found that by forming the carton in the manner described with the sets of portions of the material adhered in the manner described 3 that the leakage of liquid along the fold lines at these locations can be minimised or prevented.

In one embodiment of the invention the carton is provided with a lip portion which runs around the periphery of the carton opening, said lip depending from the side and end walls of the carton and providing a surface for attachment on or engagement with a lid or film to enclose the carton and the substance therein.

It is envisaged that the carton as herein described is of particular use in containing foodstuffs and yet further, although not necessarily exclusively, for containing foodstuffs which include liquids and which foodstuffs are not frozen such as for example, ready cooked chilled foods and the like.

In a further aspect of the invention there is provided a method of forming and erecting a carton from a blank of sheet board material, said method comprising the steps of applying a heat sealing material to selected areas of the blank, moving the blank to an erected condition by folding portions of the material and wherein the carton is retained in the erected position by providing, at selected locations, sets of portions comprising a first portion, a second portion moved into contact with the first portion and a third portion moved into contact with the first and/or second portion, and applying heat to cause the heat sealing material which is coated on selected areas of the blank to cause the second portion to adhere to the first portion, and the third portion to adhere to the first and/or second portion.

In one embodiment the heat application is performed by heating plates which are brought into contact with the area of the carton including said sets of portions and applies localised and controlled heat to cause the heat sealing material to be activated. In a preferred 4 embodiment the carton is held in a die with a central mandrel and the application of the heating plates, in addition to the application of heat, applies pressure to the portions and the fold lines of the board material in that area by pressing the same against the mandrel and causes the portions to take a flattened condition and reduce the tendency for the same to bow outwardly when the carton is formed.

The application of heat in a conductive manner and in a controlled area prevents the degradation of the liquid repellent coating on the board material and hence prevents liquid from seeping into the board material from the substance contained therein.

In one embodiment the forming method includes the additional step of applying localised heating via heating rods at corners of the erected carton to form a carton lip, said lip formed from a series of flaps, the ends of which are positioned to overlap with an end of an adjacent flap and attached together by the heating of a coating of heat sealing material.

In a further aspect of the invention there is provided a carton blank of sheet board material coated with a liquid repellent material, said blank having a base portion, and side and end wall portions depending therefrom, and each side wall having an edge which, when formed forms part of the carton opening, and wherein the adjacent edges of the side and end walls are joined by first and second side flaps of material and wherein the blank includes a set of portions at each of the side flaps, each set comprising a first portion on a side or end wall and second and third portions formed on the side flaps such that when formed, the second portion is attached to the first portion and the third portion is attached to the first and/or second portions.

Specific embodiments of the invention are now described with reference to the accompanying drawings wherein; Figure 1 illustrates a carton in accordance with one embodiment of the invention; Figures 2A C illustrate in detail part of the erecting process for the joining locations of the carton of Figure 1; Figure 3 illustrates the application of heat to attach the joining locations of Figs 2A-C; Figure 4 illustrates a carton blank for the carton of Figure 1; Figure 5 illustrates a carton in accordance with another embodiment of the invention; Figures 6A-C illustrate in detail part of the erecting process for the joining locations of the carton of Figure 5; Figure 7 illustrates a carton blank for the carton of Figure 5; and Figure 8 illustrates the application of heat to form the carton lip.

Referring firstly to Figures 1-4 there is illustrated one form of carton in accordance with the invention. The carton comprises a base portion 2, side walls 4 and 8, and end walls 6 and 10 which define a cavity 12 in which a substance such as a foodstuff is held. The carton is also provided with a lip portion 14 formed from a series of flaps 16 which edges overlap and can be sealed together when the carton is formed.

6 The edges of the end walls 6, 10 are joined to the edges of the adjacent side walls 4, 8 by first and second flaps 18, 20 as shown.

In order to erect the carton from the blank form of Figure 4 to the erected form of Figure 1 the blank is moved, typically by passing through a die with a mandrel, to a partially erect condition. As part of the invention there are provided first, second and third portions 21, 22, 24 respectively which are required to be attached together and the process of Figures 2A-C is followed at each location where these portions are provided and which positions are illustrated in Figure 4 and figures 2A-C.

In order to attach the portions and hence form the carton, heat sealable material is applied over area 26 in the first portion 21 as shown. The second portion 22 is then brought into contact with the first portion. An area of heat sealing material 28 is provided on the second portion 22 such that the third portion 24 can be brought into contact and adherence with the second portion 22 and typically also the first portion 20 as shown in Figure 2C. With the portions in position heat is applied to the area to activate the heat sealing material at areas 26,28 to attach the first, second and third portions. This process is performed at both end walls and so the carton is formed.

In a preferred embodiment the heat is applied via heating plates 30 as illustrated in Figure 3 which apply heat to the portions 21, 22, 24 when in contact with the same. In addition if a mandrel 32 is positioned in the cavity as shown the plates can be used to apply pressure to the end walls and so prevent the same from bowing and being unsightly when formed.

An alternative carton is described with reference to Figures 5-7. In this embodiment there is provide a base 102, side walls 106, 110 and 7 end walls 104,, 108, which define a cavity 112. The side walls are joined to the end walls by side flaps 118, 120 as shown. In order to erect the carton, the side walls 106,, 110 are moved towards an upstanding position and in this case the corners of the carton are formed by the attachment at each corner of first, second and third portions 121, 122:1 124 as illustrated in Figures 6A-C. In this case the first portion 121 is provided with an area of heat sealing material 126 and the second portion 122 with an area of heat sealing material 128 and in addition with heat sealing material at area 129. In this arrangement, at each corner the second 122 and third 124 portions are moved into contact as shown in Figure 6B and then moved together to be attached to the first portion 120 as shown in Figure 6C. When in position, heat is applied to activate the sealing material and cause the attachment of the portions.

Figure 8 illustrates how the lip portion 14 can be formed by the application of heat using heating pins 50 at the overlapping portions 52 of the lip edges and, when formed a lid or film can be heat sealed or otherwise attached to the lip portion.

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Claims

Claims:-

1 A carton formed from a blank of sheet board material, said carton provided for the containment of a substance and said material foldable to an erect condition to form the carton by attaching together portions of the material, and at least some of the portions are coated with heat sealable material which when heat is applied thereto activates adherence of the portions and wherein said portions comprises at least a first portion, a second portion and a third portion, and when the carton is formed, the second portion is attached to the first portion and the third portion is attached to the first and/or second portion.

2. A carton according to claim 1 wherein the third portion is attached to the first and second portions.

3. A carton according to claim 1 wherein a number of first, second and third portions are provided at spaced locations to retain the carton in an erect condition.

4. A carton according to claim 3 wherein the spaced locations of the number of first, second and third portions are at each corner of the carton.

5. A carton according to claim 4 wherein the carton is a tray form in which the side walls are relatively small compared to the area of the carton base.

6. A carton according to claim 3 wherein the spaced location of the number of first, second and third portions are at two of the side walls of the carton.

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7. A carton according to claim 6 wherein the side walls of the carton are relatively large compared to the area of the carton base.

8. A carton according to claim 1 wherein a lip portion is provided around a whole or part of the periphery of the carton opening.

9. A carton according to claim 8 wherein the lip portion depends inwardly from one or more sidewalls of the carton.

10. A carton according to claim 8 wherein the lip portion provides an engagement surface for the attachment on or engagement with a lid or film to enclose the carton and the substance therein.

11. A carton ac cording to claim 1 wherein the substance for containment in the carton is a foodstuff.

12. A carton according to claim 11 wherein the foodstuff contains a liquid.

13. A method for forming and erecting a carton from a blank of sheet board material, said method comprising the steps of applying a heat sealing material to selected areas of the blank, moving the blank to an erected condition by folding portions of the material and wherein the carton is retained in the erected position by providing, at selected locations, a first portion, a second portion moved into contact with the first portion and a third portion moved into contact with the first and/or second portion, and applying heat to cause the heat sealing material which is coated on selected areas of the blank to cause the second portion to adhere to the first portion, and the third portion to adhere to the first and/or second portion.

14. A method according to claim 13 wherein the application of heat to the carton is performed by heating plates.

15. A method according to claim 14 wherein the heating plates are brought into contact with the selected areas of the carton, which includes the first, second and third portions, and apply localised and controlled heat to cause the heat sealing material on the selected areas to be activated.

16. A method according to claim 13 wherein the carton is held in a die with a central mandrel and the application of the heating plates, in addition to the application of heat, applies pressure to the portions and fold lines of the sheet board material by pressing the same against the mandrel, thereby causing the portions to take a flattened condition.

17. A method according to claim 13 wherein an additional step is provided of applying localised heating via heating rods at corners of the erected carton to form a carton lip.

18. A method according to claim 17 wherein the lip is formed from a series of flaps, the ends of which are positioned to overlap with an end of an adjacent flap and adhered together by the heating of a coating of heat sealing material.

19. A carton blank of sheet board material coated with a liquid repellent material, said blank having a base portion, and at least four side wall portions depending therefrom, and each side wall having an edge which, when formed forms part of the carton opening and wherein each of the respective edges of adjacent side wall portions are joined by first and second side flaps and wherein there is provided a first portion on at least one of the side walls and second and third portions of the side flaps such that when formed, the second portion is attached to the first portion and the third portion is attached to the first and/or second portions.

20. A carton substantially as herein described with reference to Figures 1-8.

21. A method for forming and erecting a carton substantially as herein described with reference to Figures 1-8.