EP2091825B1

EP2091825B1 - A container

Info

Publication number: EP2091825B1
Application number: EP07804396A
Authority: EP
Inventors: Frank Mills; Michael Richmond; Philip Wright
Original assignee: Colpac Ltd
Current assignee: Colpac Ltd
Priority date: 2006-09-25
Filing date: 2007-09-25
Publication date: 2011-03-30
Anticipated expiration: 2027-09-25
Also published as: ATE503689T1; DK2091825T3; EP2091825A1; WO2008037986A1; GB2442327A; GB0618845D0; DE602007013603D1; GB0718702D0

Abstract

A blank for forming a food product container has a laminate construction comprising a paper or cardboard substrate having an aperture and an impermeable plastic sheet laid on the entire substrate and defining a window over the aperture. The blank further has webbing sections 20 provided between two panels 4, 5 to enable the sealing container to be more easily formed. The webbing sections 20 comprise at least two portions 20a, 20b and a fold line 21. The fold line 21 extends to the opening of the container when formed, so that the edges don't interfere inside the container. A hole 8 is provided in one webbing portion 20b spaced from the fold line 21, so that the plastic sheet portion of the webbing can be heat sealed against an adjacent wall.

Description

The invention relates to a container and a blank for a container, and more specifically but not exclusively, to a sandwich container and a blank for a sandwich container.
Sandwiches and other convenience foods are often pre-prepared and presented in packaging ready for purchase. The packaging used is usually manufactured from either a plastics material or from paperboard. For the purposes of this specification 'paperboard' is considered to encompass paper, cardboard and similar materials.
Given that this packaging has to be disposed of, paperboard containers are preferable from an environmental standpoint. Company specific graphics, logos and trademarks can also be applied during the manufacturing process far more easily than for plastic containers. Nonetheless, plastic containers remain popular because they are generally capable of forming a better seal and thereby prolonging the shelf life of the product contained therein. Typically, paperboard containers folded from blanks struggle to achieve a good airtight seal. The paperboard is also susceptible to damage from grease, fat or other, liquids in the food products. If grease is allowed to soak into the paperboard, then both the outward appearance and the structural integrity of the container is compromised. Even with the inclusion of a barrier coating, the shelf life of products in such containers is limited to around forty eight hours. This is because cut edges (i.e. where the blank was cut from a larger piece of treated paperboard) are generally exposed on the inside of the container. These cut edges are not protected by any provided barrier coating, and fat and grease may be readily absorbed at these points. Since these cut edges are usually to be found where the blank is bonded together, any damage caused can have a detrimental affect on the integrity of the seal provided. The integrity of the seal can also be compromised if a window, commonly a sheet of transparent plastics material bonded over an aperture in the paperboard, is provided.
The provision of webbing sections as opposed to tabs to form the join between abutting walls of the blank have been beneficial in creating a more effective seal. As shown in WO 03/018410 , these webbing sections generally comprise two areas of paperboard with a fold line in between, each connected by a further fold line to one of two abutting walls. When the blank is folded the webbing sections fold like a concertina to lie flat against one of the walls. In order to successfully bond this more complex closure, it has been necessary to use complex techniques such as heat sealing or RF welding, and/or to cut away one webbing area so that it does not extend to the full height of the other. The requirement for heat sealing or RF welding means that containers often have to be pre-formed from the blanks prior to shipping to customers. Any exposed cut edges lead to reduced integrity of the finished container, and further problems as discussed above.
Document FR 2 421 816 A1 discloses a container formed from folded thank,the thank comprising a substrate and a plastic layer applied over the entire substrate layer and forming a window over an operate provided in the substrate layer. Accordingly, it is an object of the present invention to provide a container, or a blank for a container which overcomes the above problems such that a food product container with a window with an improved seal can be provided.
According to the present invention there is provided a container having the features recited in claim 1. In a preferred embodiment the webbing section comprises two webbing portions with a fold line therebetween, one of said webbing portions comprising a discontinuity spaced from the fold line so as to allow bonding means to bond one of the abutting walls to the other one of said webbing portions when the blank is assembled.
The provision of a discontinuity spaced from the webbing fold line allows the blank to be formed into a container and easily bonded together without the integrity of the seal being compromised. The best seal is possible when the discontinuity takes the form of an aperture formed in at least one of the webbing areas.
With the discontinuity as described, it is possible to bond the container together using a standard adhesive. This is beneficial if the blanks are to be shipped to customers in an unassembled state, since they can be glued by customers using existing machinery. The blank may also be bonded, before or after shipping, by other means.
It is preferable that the fold lines which exist between panels of the blank are defined by creases rather than by scoring. A better seal can be achieved by the assembled container if this approach is taken.
A better sealing container is also achievable through the provision of a barrier coating on the blank. This coating is preferably also susceptible to heat sealing and/or RF welding to enable the container to be formed by more than one method. Suitable materials for the coating include but are not limited to plastics, for example polyethylene or acrylic.
The blank preferably folds into a substantially triangular prism with one open side, in particular into a container suitable for sandwiches.
The folded container may also comprise a flange portion around the opening and/or a folding lid which are formed as further panels of the blank.
The extension of the fold line to the opening of the assembled container eliminates cut edges from the inside of the container, thereby providing greater integrity. The blank thus described may also benefit from any of the previously mentioned features.
According to the invention the blank for assembly into a food product container comprises a substrate layer and a liquid impermeable layer, the liquid impermeable layer being applied over the entire substrate layer and forming a window over an aperture provided in the substrate layer.
Previously, it has been commonplace to cut a blank to shape, apply a liquid impermeable coating, cut a window aperture, and separately bond a window piece of plastics film over the aperture. By providing a single layer as both a liquid impermeable barrier coating and a window, the manufacture of the blank is streamlined, and the integrity of the finished container is improved.
Preferably, the liquid impermeable layer is resistant to grease, fat and other liquids found in foods. The layer is also preferably susceptible to RF welding and/or heat sealing. Plastics materials, for example polyethylene or acrylic, are suitable.
The substrate of the blank may be formed from paperboard.
Sealing is further improved if the blank comprises one or more webbing sections between adjacent panels. These webbing sections may comprise two webbing portions with a fold line therebetween, to aid folding of the blank. Preferably, one webbing portion comprises an aperture to allow access to the liquid impermeable film once the webbing sections are folded.
For ease of manufacture, the liquid impermeable coating may be applied before the final shape of the blank is cut and/or before fold lines and any apertures in webbing sections are formed. According to the invention the bonding of parts of the blank to form the container is achieved by heat sealing, for example through the use of a heat sealable coating provided on one surface of the blank. Modified tooling, specific for the task in hand, will greatly simplify the container forming process.
A better understanding of the present invention will be obtained from the following detailed description of particular embodiments. The description is given by way of example only and makes reference to the accompanying drawings in which:

Figure 1 is a plan view of a blank illustrating of a way of connecting the sidewalls of a container to each other;
Figure 2 shows the blank of Figure 1 after some initial folding;
Figure 3 shows the blank of Figure 2 close to the end of folding;
Figure 4 is a perspective view of a container formed from the blank shown in Figure 1;
Figure 5 is a plan view of an alternative blank
Figure 6 shows the blank of Figure 5 after some initial folding;
Figure 7 shows the blank of Figure 5 close to the end of folding; and
Figure 8 is a perspective view of a container formed from the blank shown in Figure 5.

The figures show blanks for a sandwich container and a noodle pot in unassembled, part assembled and assembled states.
Referring first to Figure 1, a blank is shown with webbing sections 20 between panels 4, 5 which will, in use, form abutting walls of a container 7 shown in Figure 4. The webbing sections of this particular embodiment comprise two substantially similar portions 20a, 20b with a webbing fold line 21 therebetween. Between each webbing portion 20a, 20b and an adjacent panel 5, 4; a panel fold line 9 is provided. One of the webbing portions 20b is provided with an aperture 8 which in this embodiment takes the form of a circular hole, but may be an aperture of any shape, or other discontinuity in the webbing portion 20b as indicated by dotted line 10 for example, spaced from the webbing fold line 21. The dotted line 10 shows a discontinuity in the form of a cut-away section removing part of a free edge. 22b of the webbing portion 20b. A coating (not shown) may be applied over the entire visible surface of the blank. A flange-forming portion 11 is also shown around the edge of the blank. A flange fold line 6 is provided between the flange forming portion 11 and the panels 4,5. In this embodiment, the fold lines 2, 3, 6, 9, 21 are all formed as creases.
When the blank is folded to form a container the webbing sections 20 fold like a concertina at their panel fold lines 9, and webbing fold lines 21 and lie flat against the side panels 4. The blank once folded forms a container with an opening defined by the flange fold line 6 between the outside edges of the panels 4, 5 and the flange forming portions 11. Once folded into shape the panels 4 are bonded to the webbing sections 20. The provision of the holes 8 allows bonding means applied to the side panels 4 to bond to both webbing portions 20a, 20b. A number of bonding means are applicable, but in this embodiment adhesive (not shown) is applied to the side panels 4. The adhesive is preferably applied only in the four discrete areas which will fall under the holes 8. Thereby adhesive applied to the side panels 4 passes through the holes 8 in the webbing areas 20b, and bonds the side panels 4 directly to the webbing areas 20a. Alternatively, the adhesive may be applied to the entire area which will fall under the webbing portions 20b. In this case a seal is created by the adhesive bonding both webbing portions 20a, 20b to the side panel 4 of the finished container 7.
Figures 2 and 3 show two stages of folding of the blank to form a finished container. Figure 2 shows the initial part of the folding process, with the panel fold lines 9 being folded in the opposite direction to the webbing fold lines 21 to provide the concertina type fold described above. The holes 8 can be seen approaching the side panels 4 of the blank. Figure 3 shows the blank almost completely folded. The webbing fold lines 21 are shown protruding into the inside of the container and the holes 8 are just visible within the concertina fold adjacent the side panels 4. Figure 3 also shows the flange forming portion 11 being folded back at the flange fold lines 6.
Referring now to Figure 4, with the same reference numerals used for like components, there is shown a fully assembled container 7 from the blank of Figure 1. The holes 8 are now completely covered by the webbing sections 20a, and hence are not shown in the drawing. It can be seen that the webbing fold lines 21 of the webbing sections 20 extend right to the opening of the container. As a result, the cut lines 22a, 22b at the edge of the blank, are adjacent the flange fold line 6 at the edge of the side panel 4. This arrangement means that no cut edges are exposed on the interior of the container, which minimises the possibility of ingress of fat or oil. Successful bonding of the container is still possible due to the provision of the holes 8 in the webbing portions 20b.
Figure 5 shows a plan view of a blank 101 suitable for the formation of a noodle pot, but the various features shown are equally applicable to blanks for the but the of various futures shown are equally applicable to blank for the formation of sandwich containers according to the present invention, or containers for a number of different purposes.
As in the blank 1 of Figure 1, the blank 101 has webbing sections 120 between panels 104, 105 which will, in use, form abutting walls of a container 107 shown in Figure 8. Two webbing portions 120a, 120b make up each webbing section 120. A webbing fold line 121 is provided between the first webbing portion 120a and the second webbing portion 120b. The second webbing portion 120b is shown with an aperture 108 therethrough, although this is not essential. A flange forming portion 111 is also provided around the edge of the blank 101 to form a flange when the container 107 is in its folded state. The blank 101 of Figure 5 has a rectangular base panel 110 having a major and minor sides. The larger wall panels 104 extend from each of the major sides of the base panel 110. Major base fold lines 103 are provided between the base panel 110 and the larger side panels 104. Similarly, minor base fold lines 102 are provided between each minor side of the base panel 110 and each smaller side panel 105. Panel fold lines 109 are provided between the webbing section 120 and each side panel 104, 105, and flange fold lines 106 between each side panel 104, 105 and the flange forming section 111 of the blank 101. The flange forming portion 111 is provided in three separate parts, one part joined to each smaller side panel 105, and one part joined to one of the larger side panels 104. Each side panel 104, 105 is in the shape of an isosceles trapezium, such that the folded container 107 has an opening larger than its base panel 110.
Unlike the sandwich box blank 1 of Figure 1, the blank 101 of Figure 5 further includes a lid panel 124. The lid panel 124 extends from the edge of one of the larger side panels 104 opposite to the base panel 110. A lid fold line 126 is provided between the lid panels 124 and the larger side panel 104. A window portion 128 spans the lid panel 124 and the major side panel 104, crossing the lid fold line 126. The window portion 128 comprises a transparent plastics material.
The method of forming the blank 101 of Figure 5 will now be described.
A substrate material, in this instance paperboard, is die cut to a suitable size, and an aperture is die cut to form the window portion 128 of the finished blank 101. A liquid impermeable film, for example polyethylene, is then laminated over the entire substrate, filling in the window portion 128. The two layer laminate material is then die cut to the desired shape for the finished blank 101, fold lines 102, 103, 106, 109, 121, 126 are formed, as creases, where required, and apertures 108 are die cut in the second webbing portions 120b. The finished blank 101 therefore benefits from a single, continuous coating which serves as both a liquid impermeable film inside the container 107 once folded to prevent grease, fat or other liquids present in the food product from soaking into the paperboard substrate, and as a window portion 128 in the finished container 107. The coating can additionally, or alternatively, serve as a heat sealable film to bond the container 107 together.
By providing a single coating layer serving a number of purposes, the manufacturing process is simplified. Also, the lack of discontinuities in the coating means that the integrity of the finished container 107 is also improved. This integrity can be further improved by forming the container 107 in a particular way, as described below with reference to Figures 6 to 8.
A blank 101, as shown in Figure 5 is formed as described above. The side panels 104, 105 are folded towards each other to form a tub-like shape, with a heat sealable film on the inside. As the side panels 104, 105 are folded at the major base fold lines 103 and minor base fold lines 102, the panel fold lines 109 will naturally fold in the opposite direction to the webbing fold lines 121, causing the webbing sections 120 to concertina. This concertina action is shown in Figure 6. Significantly, the webbing sections 120 should, at this stage, be made to fold to the outside of the container 107.
When the larger side panels 104 and the smaller side panels 105 are in abutment, the first webbing portions 120a and the second webbing portions 120b are pressed together and heat sealed to one another. The base panel 110, larger side panels 104 and smaller side panels 105 now form a substantially sealed tub shape, with no part of the folded blank 101 extending into the interior. The sealed webbing sections 120 extend outwards from the corners of the tub formed by the side panels 104, 105 as shown in Figure 7.
A small amount of the heat sealable film provided on each first webbing portion 120a is visible through the aperture 108 provided in each of the second webbing portions 120b. The webbing sections 120 are folded back against the outside of the tub, such that the aperture 108 of each second webbing portion 120b lies against the outside of a smaller side panel 105. The webbing sections 120 are then heat sealed to the outside of the smaller side panels 105 to provide greater structural strength to the container 107, and to improve the seal. The flange forming portions 111 are folded back to form a flange to which the lid panel 124 can seal once food has been placed in the container 107. The finished container 107 is shown in Figure 8. The lid panel 124 can be heat sealed, RF welded or bonded by some other suitable means.
By forming the container 107 as described above, a good seal can be formed. Typically, webbing portions 120 are folded to the inside of a finished container 107, where the edges of said webbing portions are susceptible to the ingress of fats and oils from food provided in the container 107. Folding the webbing outwardly, as herein described, avoids these problems. Furthermore, by folding the webbing sections 120 to the outside when forming the container 107, they are more easily accessible for heat sealing to one another, which provides a better seal for the finished container.
The method described above would also be applicable to containers of other shapes and configurations, for example, where a lid is provided as a separate component. Also, while the provision of apertures in the webbing is preferable, it is by no means required. A blank 101 could be folded as above, with the webbing sections bounded together by heat sealing or other means, and then simply glued to the outside of the container.
The present invention is not limited to the specific embodiments described above. Alternative arrangements will be apparent to a reader skilled in the art. For example the shape and form of the webbing sections may vary from that shown, as may the shape of the container. A lid may additionally be provided, either as a separate component or as an additional panel of the blank.

Claims

A sandwich container (7,107) formed from a folded blank, wherein a webbing section (20) is provided between two panels (4,5) of the blank which form two abutting walls of the container, the blank comprising a substrate layer and a liquid impermeable layer, the liquid impermeable layer being applied over the entire substrate layer and forming a window (128) over an aperture provided in the substrate layer, characterised in that the container (7,107) is bonded together by heat sealing of the liquid impermeable layer.
A container (7,107) according to claim 1, wherein the liquid impermeable layer is susceptible to RF welding.
A container (7,107) according to claim 1 or 2, wherein the liquid impermeable layer is a plastics material such as polyethylene or acrylic.
A container (7,107) according to any of the preceding claims, wherein the substrate is of paperboard.
A container (7,107) according to any of the preceding claims, wherein an aperture (8) is provided in the webbing section (20).
A container (7,107) according to any of the preceding claims, wherein the webbing section (20) comprises two webbing portions (20a,20b) with a fold line (21) therebetween.
A container (7,107) according to claim 6, wherein the end of the fold line (21) is adjacent an opening of the container (7,107) provided to receive food product.
A container (7,107) according to claim 6 or 7, wherein the fold line (21) provided is a crease in the blank.
A blank for forming a food product container (7,107) as claimed in any of the preceding claims.
A blank according to claim 9 further comprising a substantially rectangular central panel (118) with opposed pairs of major and minor sides (103,102), and two pairs of further panels (104,105) integrally connected to the central panel (110) at the major and minor sides (103,102) respectively, one pair of side panels (104) having side edges (109) which extend at oblique angles to the sides (102) of the central panel (110).