GB2558110A

GB2558110A - A Carton

Info

Publication number: GB2558110A
Application number: GB1805271.2A
Authority: GB
Inventors: Mercer William; Neale Steven
Original assignee: Coveris Flexibles UK Ltd
Current assignee: Coveris Flexibles UK Ltd
Priority date: 2015-10-13
Filing date: 2015-10-13
Publication date: 2018-07-04
Anticipated expiration: 2035-10-13
Also published as: GB2558110B; GB201805271D0

Abstract

A film having a laminate structure comprising: i) an outer layer comprising polyolefin, ii) a puncture resistant layer of polyethylene, iii) a tie layer of bonding resin, iv) an oxygen barrier layer, v) a further tie layer of bonding resin, vi) an anti-mist layer and vii) a pack sealing layer comprising polyethylene and a plastomer. The sealing layer may comprise low-density polyethylene and metallocene catalysed linear low-density polyethylene. The film may have additional puncture resistant layers comprising polyethylene. The outer layer may comprise polypropylene or polyethylene. The oxygen layer may comprise ethylene vinyl alcohol. The film may be a barrier material for a food carton, the carton comprising a substrate and the barrier.

Description

(54) Title of the Invention: A Carton

Abstract Title: Laminate film for a food carton (57) A film having a laminate structure comprising: i) an outer layer comprising polyolefin, ii) a puncture resistant layer of polyethylene, iii) a tie layer of bonding resin, iv) an oxygen barrier layer, v) a further tie layer of bonding resin, vi) an anti-mist layer and vii) a pack sealing layer comprising polyethylene and a plastomer. The sealing layer may comprise low-density polyethylene and metallocene catalysed linear low-density polyethylene. The film may have additional puncture resistant layers comprising polyethylene. The outer layer may comprise polypropylene or polyethylene. The oxygen layer may comprise ethylene vinyl alcohol. The film may be a barrier material for a food carton, the carton comprising a substrate and the barrier.

FIG. 1

1/3

FIG. 1

2/3

FIG. 2

3/3

FIG.3

A carton

FIELD OF THE INVENTION

The present invention relates to a carton for food. The present invention further relates to a blank for forming a carton for food, and a method of forming a carton from a blank. The present invention further relates to a film for a carton.

BACKGROUND OF THE INVENTION

It is known to create a food carton such as a sandwich carton from a substrate protected by a layer of barrier material. For example, the substrate may be laminated with a film of plastics material secured to the substrate by adhesive to act as a liquid and vapour barrier, and to act as a pane in any viewing openings provided in the carton. Sandwich cartons are typically triangular or wedge-shaped to accommodate usually one, two or three diagonally cut sandwiches made from two initially square layers of bread with a filling therebetween. The width of the carton may vary depending upon the number of individual sandwiches, the thickness of bread and the depth of the filling.

Such a carton usually has a body and a lid, the lid being sealed against the body once the carton has been filled. Typically, the lid is sealed against flanges extending from the body for that purpose. Substantially complete sealing of the carton is desirable, in order to ensure the sandwiches remain fresh and do not spoil up until their designated use by date.

It can be difficult to achieve substantially complete sealing of the carton. The carton body often includes folded or hinged panels, in order to allow the carton to be quickly and easily erected from a blank. Such folds and hinges can create gaps and thus inadvertently allow air to enter the body of the carton

The present invention seeks to overcome or at least mitigate the problems of the prior art.

SUMMARY OF THE INVENTION

According to an aspect of the invention there is provided a carton for food, the carton comprising a body configured to receive food, the body defining an opening; and a lid secured to the body at a first edge thereof and configured for sealing in a closed position over the opening. At least the body comprises a substrate and a barrier material. The barrier material extends beyond the substrate at the first edge so as to form a skirt; and the skirt is configured to be folded towards the opening upon movement of the lid towards the closed position.

The skirt being folded towards the opening creates a layer of barrier material at the first edge, improving sealing and so reducing airflow into the carton body.

The body may comprise a hinged panel arrangement, and the skirt may extend beyond the substrate at the hinged panel arrangement. The skirt may extend from the hinged panel arrangement. The skirt may extend along substantially the full length of the hinged panel arrangement. The hinged panel arrangement is a formation which could potentially allow airflow into the carton body. The skirt is thus advantageously situated at the hinged panel arrangement.

The skirt may extend beyond the first edge by between 2 mm and 7 mm. The skirt may extend beyond the first edge by between 3 mm and 5 mm. The skirt may be substantially uniform in height. A skirt of a height in this range provides sufficient sealing over the first edge.

The lid may define a window, and the skirt may not reach the window when the lid is in the closed position. The skirt advantageously does not affect the window.

The body may be substantially a triangular prism. This is a commonly used carton shape, suitable for triangular shaped sandwiches.

There is further provided a blank for forming a carton as described above. The blank may comprise first and second substantially rectangular end walls hingedly connected together; first and second triangular side walls hingedly connected to opposing edges of the first end wall; and a hinged panel arrangement provided between the second end wall and the second side wall, the hinged panel arrangement comprising first and second panels, the first hinge panel being hingedly connected to the second end wall, the second hinge panel being hingedly connected to the first hinge panel, and being securable in a face-contacting relationship to the second side wall to facilitate the erection of a carton from the blank. The blank comprises a substrate and a barrier material; and the barrier material extends beyond the substrate at an outer edge of one or both of the first and second hinge panels so as to form a skirt.

The blank may further comprise a lid hingedly connected to the second side wall.

There is yet further provided a method of forming a carton from a blank as described above, the method comprising the steps of:

a) partially erecting the carton from the blank;

b) filling the carton with foodstuff;

c) moving the lid to the closed position, such that the skirt is folded over the outer edge of the first and second hinge panels.

The barrier material may be a film having a laminate structure comprising an outer sector, core and inner sector often comprising the following layers;

i) an outer layer, typically comprising a polyolefin such as polypropylene and/or polyethylene;

ii) one or more puncture resistant layers often comprising polyethylene;

iii) a tie layer often comprising a bonding resin;

iv) an oxygen barrier layer, often ethylene vinyl alcohol;

v) a further tie layer, often comprising a banding resin;

vi) optionally one or more further puncture resistant layers, often comprising polyethylene;

vii) an anti-mist layer; and viii) a pack sealing layer often comprising polyethylene and a plastomer.

The outer layer is laminated to the blank, is generally heat resistant and often has a surface gloss to improve aesthetic appearance. In many cases the polyethylene will be low density polyethylene, often linear low-density polyethylene. A processing aid such as a lubrication additive may also be present to increase output and visual appearance.

There may be one, two, or three puncture resistant layers, often two layers adjacent to one another and the outer layer to provide an outer sector comprising an outer and one or two puncture resistant layers. Where a third puncture resistant layer is present, this will often be part of the inner sector, often adjacent to the core.

The tie layers form part of the core together with the oxygen barrier. The tie layers bond the inner and outer sectors to the core and are often formed of resin to reduce or prevent ingress by the anti-mist additive.

The anti-mist layer ensures that the aesthetics of the barrier material are maintained preventing misting. This layer is adjacent the core where only two puncture resistant layers are present, or adjacent a puncture resistant layer where one is present in the inner sector.

Adjacent the anti-mist layer is the pack sealing layer, the plastomer reducing the softening point of this later to facilitate welding.

In some examples the barrier layer may be a film comprising;

i) polypropylene, metallocene catalysed linear low-density polyethylene, a processing aid and an anti-blocking agent such as silica;

ii) linear low-density polyethylene iv) tie layer

v) ethylene vinyl alcohol vi) tie layer viii) linear low-density polyethylene ix) low-density polyethylene, metallocene catalysed linear low-density polyethylene plastomer wherein the layers are configured in the above order, and wherein layer i) is configured to be proximal the substrate.

The film may further comprise the following layer:

iii) linear low-density polyethylene.

The film may further comprise the following layer:

vii) linear low-density polyethylene.

In this example item i) functions as the outer layer; items ii), iii) and vii) as the puncture resistant layers; items iv) and vi) as the tie layers; item v) as the oxygen barrier layer; item viii) as the anti-mist layer and item ix) as the pack sealing layer.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a cross-sectional view through a carton according to an embodiment of the invention in a partially erected state;

Figure 2 is a schematic cross-sectional view through the carton of Figure 1, as a lid is moved to a closed position; and

Figure 3 is a plan view of a blank for the carton of Figure 1.

DETAILED DESCRIPTION OF EMBODIMENT(S)

A partially erected carton for triangular cut sandwiches is indicated at 10 in Figure 1. The carton 10 is typically manufactured from a paperboard substrate 12 covered over its inner face with a thin, transparent film of barrier material 14. The substrate 12 provides rigidity to the carton 10. The barrier material 14 provides a moisture barrier to hold liquid sandwich ingredients such as mayonnaise within the carton 10, preventing leaching into the substrate and subsequent deterioration in appearance and strength. The barrier material 14 inhibits the release of moisture as vapour from the finished carton 10, and so extends the shelf life of the carton contents by inhibiting the staling process. The barrier material 14 may also act to maintain an atmosphere with the carton that slows the decay of vegetable matter, further enhancing the shelf life of certain sandwich varieties. In addition, the barrier material 14 provides a covering for any window in the carton 10.

The carton 10 has a body 16 configured to receive food. The body 16 is in this embodiment triangular-prism shaped, and is configured to receive a triangular sandwich. The body 16 defines an opening 18 to allow food to be placed in and removed from the carton 10.

The carton 10 has a lid 20 secured to the body 16. The lid 20 is movable to a closed position where it can be sealed against flanges (not shown) perpendicular to the plane of the opening 18, so as to cover the opening 18 and close the carton 10. This may typically be achieved by heat sealing of the barrier material face of the lid 20 to the barrier material face of the flanges. Adhesive or RF welding may also be used. The lid 20 is hingedly secured to the body 16 along a first edge 22 of the body 16. The edge 22 forms one side of the opening 18.

When the carton 10 is in the partially erect position shown in Figure 1, the barrier material 14 extends beyond the substrate 12 at the first edge 22 so as to form a skirt 24. The skirt 24 is at the inner face 20a of the lid 20, so is configured to be folded towards the opening 18 upon movement of the lid 20 towards the closed position. This arrangement is shown in the schematic Figure 2, where the lid 20 is moved partway to the closed position and the skirt 24 is folded inwardly towards the opening 18. The skirt 24 is configured to cover a potential air inlet in the carton 10, improving sealing with the advantages set out above.

Figure 3 shows the carton blank 26. The blank 26 has first 28 and second 30 substantially rectangular end walls hingedly connected together and first 32 and second 34 triangular side walls hingedly connected to opposing edges of the first end wall 28. The second side wall 34 is in this embodiment formed from a single panel.

The blank 26 has a hinged panel arrangement 36, 38 between the second end wall 30 and the second side wall 34. The hinged panel arrangement has first 36 and second 38 triangular panels of substantially similar size. In this embodiment, the second hinge panel defines cut-outs 39 in the substrate. However, in alternative embodiments, there may be cut-outs of some other shape in the blank 26, or there may be no such cut-outs.

The first hinge panel 36 is hingedly connected to the second end wall 30. The second hinge panel 38 is hingedly connected to the first hinge panel 36. The second hinge panel 38 is securable in a face-contacting relationship to the second side wall 34, and the first hinge panel 36 is securable in a face-contacting relationship to the second hinge panel 38, as shown in Figure 2. This configuration facilitates the erection of the carton 10 from the blank 26. However, this configuration also creates a potential airflow route into the carton 10 between the first 36 and second 38 hinge panels, as indicated by the arrow x. The skirt 24 reduces airflow into the carton 10 via this route as described below.

The hinge panels 36, 38 have an outer edge 40, i.e. an edge that is exposed and is not connected to a further part of the blank 26. When the carton 10 is partially or wholly erected the edge 40 is substantially aligned with the edge 22 of the opening 18. The barrier material 14 extends beyond the substrate 12 at the outer edge 40 so as to form the skirt 24, so that when the carton 10 is partially erected the skirt 24 extends beyond the substrate 12 at the edge 22.

As shown in Figure 2, when the lid 20 is moved towards the closed position, the skirt 24 is moved by the lid 20 towards the opening 18, such that the skirt 24 is folded over the first hinge panel 36. When the lid 20 is in the closed position, the skirt 24 will be moved to a folded position where it is substantially perpendicular to the hinge panels 36, 38, such that the airflow route x is covered, and the ingress of air into the carton 10 is inhibited.

In this embodiment, the skirt 24 extends substantially along the full length of the outer edge 40. Airflow into the carton 10 is therefore inhibited along the full length of the hinged panel arrangement 36, 38. The skirt 24 thus extends partway along the length of the edge 22. In an alternative embodiment, the skirt 24 extends only along the second hinge panel 38. This arrangement provides a skirt that will cover the full length of the outer edge 40 when folded, so inhibiting airflow into the carton 10.

The skirt 24 is in this embodiment of uniform height. That is, the skirt 24 extends beyond the substrate 12 by a uniform distance y, shown in Figure 3. In an alternative embodiment, the skirt 24 varies in height along its length. In this embodiment, the skirt 24 extends beyond the substrate 12 by between 3 and 5 mm. In an alternative embodiment, the skirt 24 extends beyond the substrate 12 by between 2 mm and 7 mm. The skirt 24 extends beyond the substrate 12 by a distance far enough to inhibit ingress of air into the carton

10 when the skirt 24 is in the folded position.

The lid 20 defines a window 42. The window 42 is at a distance z from the edge 22, as shown in Figure 1. The height y of the skirt 24 is less than the distance z, so that the skirt 24 does not interfere with the window 42 when the lid 20 is in the closed position.

In alternative embodiments, the carton body is of a different shape, and is configured to receive a sandwich of some other shape or some other type of food such as salad or noodles. The skirt may extend from some other part of the carton, e.g. the edge 22, where it would cover the airflow route x.

The barrier material 14 of this embodiment is a polypropylene/polyethylene co-extruded film with an ethyl vinyl alcohol barrier. The film 14 is a blown film, advantageously providing a natural stretch.

A sample composition of the film 14 is shown in Table A below:

Table A

	Layer	+	Grade	Mix %	Layer %	Overall %	Melt Index	Melt Temp	Pressure Rating	Material Output	Max Output	Density
	1	A	PP-CO	93.0%	17.14%	15.94%	1.80	158	4	0	100	0.910
		B	MLLDPE -S	5.0%		0.86%	1.00	118	-	-	-	0.918
		C	PROCESS	1.0%		0.17%	2.50	120	-	-	-	0.920
			AID
		D	ANTI - BLOCK	1.0%		0.17%	13.00	120	-	-	-	0.920
LJJ O ω			SILICA

H 3	2	A	LLDPE C6	100.0%	11.43%	11.43%	0.90	150	6	0	120	0.920
o		B	-	0.0%		0.00%	-	-	-	-	-	-
		C	-	0.0%		0.00%	-	-	-	-	-	-
	3	A	LLDPE C6	100.0%	8.57%	8.57%	0.90	150	6	0	120	0.920
		B	-	0.0%		0.00%	-	-	-	-	-	-
		C	-	0.0%		0.00%	-	-	-	-	-	-
	4	A	TIE MIG RES	100.0%	8.57%	8.57%	1.00	125	1	0	120	0.915
		B	-	0.0%		0.00%	-	-	-	-	-	-
		C	-	0.0%		0.00%	-	-	-	-	-	-
	5	A	EVOH - 32%	100.0%	8.57%	8.57%	0.00	193	1	0	120	1.200
LJJ
DC o		B	-	0.0%		0.00%	-	-	-	-	-	-
o		C	-	0.0%		0.00%	-	-	-	-	-	-
	6	A	TIE MIG RES	100.0%	8.57%	8.57%	1.00	125	1	0	120	0.915
		B	-	0.0%		0.00%	-	-	-	-	-	-
		C	-	0.0%		0.00%	-	-	-	-	-	-
	7	A	LLDPE C6	100.0%	8.57%	8.57%	0.90	150	6	0	105	0.920
		B	-	0.0%		0.00%	-	-	-	-	-	-
		C	-	0.0%		0.00%	-	-	-	-	-	-
	8	A	LLDPE C6	96.0%	11.43%	10.97%	0.90	150	6	0	120	0.920
LJJ O		B	ANTI - MIST	4.0%		0.46%	2.50	120	-	-	-	0.930
ω z		C	-	0.0%		0.00%	-	-	-	-	-	-
	9	A	LDPE	64.0%	17.14%	10.97%	0.40	116	4	0	160	0.927
		B	MLLDPE + S	20.0%		3.43%	1.00	118	-	-	-	0.918
		C	PLASTOMER	10.0%		1.71%	1.00	100	-	-	-	0.902
		D	ANTI - MIST	6.0%		1.03%	2.50	120	-	-	-	0.930

Glossary:

PP - polypropylene

MLLDPE - metallocene linear low-density polyethylene LLDPE - linear low-density polyethylene TIE MIG RES - migration resistant tie layer

EVOH - ethylene vinyl alcohol. In this embodiment, a 32 mol % EVOH,

Layer 1 is proximal the substrate 12, and is laminated to the substrate.

Advantageously, layer 1 provides heat resistance and surface gloss for the window. Layer 2 is strong, and provides puncture resistance. Layers 4 and 6 are migration resistant resin tie layers which bond the barrier layer into the laminate structure. They are resistant to ingress by the anti-mist reservoir of layer 8. Layer 5 provides an oxygen barrier. Layer 9 provides sealing, and contains low seal temperature grade plastomer for an improved weld.

A sample of suitable layer thickness is shown in Table B:

Table B

Layer	Layer %	Micron
1	17.14%	6.0
2	11.43%	4.0
3	8.57%	3.0
4	8.57%	3.0
5	8.57%	3.0
6	8.57%	3.0
7	8.57%	3.0
8	11.43%	4.0
9	17.14%	6.0
Total Micron (pm)	35.0
Density (g/cm³)	0.943
Unit Weight (g/m²)	32.99

Layers of this thickness provide a suitable film 14. In an alternative embodiment, layers of other suitable thickness are used.

In an alternative embodiment, the composition does not include layers 3 and 7.

Claims

1. A film having a laminate structure comprising the following layers:

i) an outer layer comprising a polyolefin;

ii) a puncture resistant layer of polyethylene;

iii) a tie layer of bonding resin;

iv) an oxygen barrier layer;

v) a tie layer of bonding resin;

vi) an anti-mist layer; and vii) a pack sealing layer comprising polyethylene and a plastomer.

2. A film according to claim 1 wherein vii) comprises low-density polyethylene and metallocene catalysed linear low-density polyethylene.

3. A film according to claim 1 or claim 2 further comprising one or more further puncture resistant layers comprising polyethylene.

4. A film according to any one of claims 1 to 3 wherein the outer layer comprises polypropylene and/or polyethylene.

5. A film according to any one of claims 1 to 4 wherein the oxygen barrier layer comprises ethylene vinyl alcohol.

6. A carton for food comprising a substrate and a barrier material, wherein the barrier material is a film according to any preceding claim.

Intellectual

Property

Office

Application No: GB1805271.2 Examiner: Mr Aidan Black