GB2574488A

GB2574488A - Aluminium foil tray

Info

Publication number: GB2574488A
Application number: GB1818244.4A
Authority: GB
Inventors: Stevens Oliver
Original assignee: I2r Packaging Solutions Ltd
Current assignee: I2r Packaging Solutions Ltd
Priority date: 2018-11-08
Filing date: 2018-11-08
Publication date: 2019-12-11
Anticipated expiration: 2038-11-08
Also published as: GB201818244D0; GB2574488B

Abstract

An aluminium foil tray 10, comprising a base wall 12, which has a downwardly projecting bead 30 around the outer perimeter thereof, and at least one side wall 14 having at least one inwardly projecting vertical rib 20 that intersects with and forms a discontinuity 25 in the bead. The rib may have a flat crest 24 and sides 26 and may taper into the side wall at the top. Preferably there are four walls 14a-d each with ribs, at least one of which may be an outwardly projecting vertical rib 40. The base may have a planar area with indented impressions that may be triangular, chevrons or hexagons (38, 34 and 32, respectively, figure 2). The impressions may cover 30% of the surface. There may be a smooth flanged rim 16 around the top of the walls and the tray may have rounded corners. A round tray (410, figure 11) with three base impressions (436, 437, figure 11) having at least five corners is also described.

Description

Aluminium Foil Tray

FIELD

The present invention relates to an aluminium foil tray, more particularly, but not exclusively, an aluminium foil tray for use in food packaging applications.

BACKGROUND

Food is often packaged, sold and/or cooked in lightweight, disposable packaging. One such example is an aluminium foil tray. These are typically manufactured via pressing an aluminium foil sheet between a male and female die.

One conventional aluminium foil tray is known as a wrinklewall tray. This type of tray has a wrinkled flange around the rim, on top of which a cover can be placed. The edge of the wrinkled flange can be folded over the cover to fix it in place, sealing the food inside the tray. The cover is often made of a rigid material such as cardboard.

The seal created by the folded flange on a wrinklewall tray is typically not liquid-tight, meaning non-solid food has to be stored upright to prevent leakage. The seal is also not typically airtight, meaning food can spoil more quickly than in a hermetically-sealed package. Such trays are often used for supplying takeaway type foods which are consumed soon after being prepared, so these issues may not be relevant.

Another conventional aluminium foil tray is known as a smoothwall tray. This type of tray has a smooth flange around the rim, allowing it to be covered and hermetically heat sealed with a film such as clear plastic. Gas flushing can also be used to provide a preservative atmosphere, increasing the shelf-life of the food within the tray.

Smoothwall aluminium trays are often used to package ready meals and meat from supermarkets that can be heated or cooked in the tray. Therefore, the possibility of extending the shelf life is important. In addition the smooth flange means the tray presents a more 'premium' image, due to the neater appearance of the smooth flange. Therefore, the appearance and integrity of the tray is significant. For this reason thicker gauges of aluminium foil are typically used for smooth wall trays, to better withstand the forces exerted on the tray during the distribution chain. This results in a more expensive tray due to higher material costs.

Both smoothwall and wrinklewall trays can be prone to tearing when being pressed into shape by the male and female dies, particularly in the corners where the side walls meet the base. Aluminium foil trays are also prone to tearing, denting or other deformation via forces exerted on the trays in filling, storage and distribution.

The present invention seeks to overcome or at least mitigate one or more problems associated with the prior art.

SUMMARY

According to a first aspect of the present disclosure, an aluminium foil tray is provided, comprising:

at least one side wall comprising at least one substantially vertically arranged rib; and a base wall comprising a bead around the outer perimeter thereof, the bead projecting downwardly so as to form a ridge on the lower face of the base wall and a depression in the upper face of the base;

the base wall and at least one side wall being configured to define a chamber for containing material to be stored;

and wherein:

the at least one rib projects inwardly so as to form a ridge on an inner face of the at least one side wall and a depression on an outer surface of the at least one side wall; and the at least one rib intersects with the bead, defining a discontinuity in the bead.

Advantageously this provides a greater strength to the tray, and in particular the side walls and interface of the side wall and base wall at a given gauge of aluminium foil, and thereby enables a reduction in materials to be achieved. In addition the tray may continue to be formable in a high speed pressing operation, and nestable with other similar trays for transport and storage

According to a second aspect of the present disclosure, an aluminium foil tray is provided, comprising:

at least one side wall; and a base wall comprising at least three impressions;

and wherein:

the outer perimeter of at least three base impressions is of a substantially polygonal shape; and the outer perimeter of at least three base impressions comprises at least five corners.

Advantageously this provides a greater strength to the tray, and in particular the base wall at a given gauge of aluminium foil, and thereby enables a reduction in materials to be achieved. In addition the tray may continue to be formable in a high speed pressing operation, and nestable with other similar trays for transport and storage.

Optionally, the side wall further comprises an inwardly projecting rib, wherein the at least one rib comprises in profile a flat crest of the rib.

This arrangement may further enhance the strength of the side wall.

Optionally, the at least one rib comprises in profile flat sides of the rib.

This arrangement may still further enhance the strength of the side wall.

In exemplary embodiments, the sides of the at least one rib have an included angle of between 155° and 115° with respect to the crest, preferably 145° and 125°, more preferably around 135°.

This arrangement may enhance the strength whilst ensuring the tray continues to be nestable and formable in a pressing operation.

Optionally, the at least one rib tapers into the side wall towards an upper end of the rib.

This ensures that the rib does not interfere with the formation of an upper part of the tray, such as a peripheral flange.

In exemplary embodiments, the at least one rib curves inwardly to intersect with the bead. This arrangement may still further enhance the strength of the side wall whilst ensuring that the high speed forming of the tray can be reliably performed.

In exemplary embodiments, the width of the bead is between 5mm and 8mm.

A bead of this width has been found to minimise unwanted flexing of the tray around the perimeter thereof, but remains formable in a high speed pressing operation.

The tray of any preceding claim, wherein the tray comprises four side walls, at least two walls each comprising at least one substantially vertically arranged and inwardly projecting rib.

This arrangement may enable sufficient strength to be provided in highly loaded locations, for example where a wrap-around sleeve is to encircle the tray.

In exemplary embodiments, each wall comprises at least one substantially vertically arranged and inwardly projecting rib.

This arrangement may further enhance the strength of all of the side walls.

Optionally, the base wall concentrically within the bead is a planar surface at substantially the same level as the discontinuity and connected therewith, preferably wherein the planar surface is continuous around the full length of the bead.

This arrangement may further enhance the strength of the side wall and interface of the base and side wall.

Optionally, a central region is defined inwardly of the planar surface.

In exemplary embodiments, the base wall comprises a planar surface and at least two impressions at a lower level than the planar surface defining an intermediate ridge having a surface co-planar with the planar surface.

This arrangement may further enhance the strength of the base, in particular to inhibit the base from sagging under the weight of material held within the tray.

In exemplary embodiments, the impressions are non-linear.

This may assist in inhibiting sagging in multiple directions.

In exemplary embodiments, the impressions comprise two straight portions arranged at an angle to each other.

In exemplary embodiments, an included angle between the straight portions is between 100° and 140°, preferably between 110° and 130°, more preferably substantially 120°.

In exemplary embodiments, the impressions are arranged such that the included angles face a centre of the base wall.

This may further assist in inhibiting sagging in multiple directions.

Optionally, the impressions have a chevron shape.

In exemplary embodiments, at the centre of the base wall an impression or surface coplanar with the planar surface has a polygon shape.

In exemplary embodiments, the polygon is a hexagon.

In exemplary embodiments, the base impressions cover at least 30% of the surface of the base.

Optionally, the tray comprises a smooth flanged rim around the top of the at least one wall.

Optionally, the tray comprises four side walls, wherein the upper rim of the tray comprises rounded corners between adjacent walls.

In exemplary embodiments, the tray comprises at least one rib arranged substantially vertically, wherein the at least one rib projects outwardly.

The provision of an outwardly extending rib may provide a contact point for engagement with a sleeve to be disposed around the tray.

In exemplary embodiments, the thickness of the aluminium foil is between 0.08mm and 0.2mm, optionally between 0.08 and 0.15mm, optionally between 0.08mm and 0.12mm, preferably between 0.090mm and 0.95mm, more preferably substantially 0.092mm.

The depth of the impression may be between 0.5mm and 1.5mm, optionally 0.8mm and 1.2mm, optionally substantially 1mm.

Optionally, the angle of the sides of the downward bead projections to the plane of the base is between 42° and 71° , optionally substantially 57°.

The inward ribs may project between 0.5mm and 2mm from the side wall, optionally between 0.8mm and 1.5mm, optionally substantially 1.4mm.

The width of the inwardly projecting rib may be between 5mm and 9mm, optionally substantially 7mm.

The edges of at least one base impression may be defined by both an inner perimeter and an outer perimeter, the inner perimeter and outer perimeter having the same centre and shape, and wherein the radius of the inner perimeter is shorter than the radius of the outer perimeter.

Optionally, the radius the inner perimeter may be shorter than the radius of the outer perimeter by between 3mm and 10mm.

DETAILED DESCRIPTION OF THE DRAWINGS

Embodiments are now described by way of example only with reference to the accompanying drawings, in which:

Figure 1 is an isometric view of an aluminium tray according to an embodiment;

Figure 2 is a plan view of the tray of Figure 1;

Figure 3 is a side view of the tray of Figure 1;

Figures 4 and 5 are isometric and plan views of a tray according to another embodiment;

Figures 6 and 7 are isometric and plan views of a tray according to a still further embodiment;

Figures 8 and 9 are isometric and plan views of a tray according to another embodiment;

Figures 10 and 11 are isometric and plan views of a tray according to a still further embodiment;

Figures 13, 14 and 15 are experimental results of crush strength testing applied to an embodiment of the present invention and to a tray of the prior art; and

Figure 16 is experimental results of tensile strength testing applied to an embodiment of the present invention and to a tray of the prior art.

DETAILED DESCRIPTION

With reference to Figures 1, 2 and 3 a smooth wall aluminium tray according to an embodiment is depicted at 10. The tray 10 is generally oblong in plan view and comprises a base wall 12 and four side walls 14a, b, c and d, extending general upwardly from the base wall. Each of the walls is inclined outwardly slightly from the vertical to permit manufacture of the tray 10 and also to enable it to nest with other trays of the same shape (i.e. stack one inside the other to minimise the space required in transit and storage prior to filling).

A continuous peripheral lip or flange 16 extends outwardly from the top of the side walls 14a-14d. The flange 16 has a generally smooth upper surface to enable a film lid to be secured thereto (e.g. by heat sealing) and has a curled outer edge 18 for rigidity and to avoid a potentially sharp cut edge being contactable by an end user.

Such a tray 10 is typically used for containing food products that may be cooked within the tray such as ready meals or poultry. As such the heat resistant qualities of aluminium are desirable. Trays 10 of this type are denoted as smoothwall trays due to this smooth upper surface of the flange 16.

It should further be noted that this tray of this embodiment has arcuate corners at the top of the side walls 14a-14d but flattened corners proximate the base wall 12 i.e. the base has effectively an unequal octagonal footprint.

Trays 10 of this type are manufactured by pressing the shape into a sheet of aluminium using suitable male and female dies (not shown).

As can be seen from Figures 1 to 3, the side walls 14a to 14d and base wall 12 are provided with various shaped features which either project inwardly or outwardly from a nominal wall location. By outwardly we mean that a feature projects externally of the volume enclosed by the nominal wall position, and by inwardly we mean that the feature extends into the volume defined by the nominal wall position.

Firstly considering the side walls 14a-d, it can be seen that the longer walls 14a, 14c each comprise five inwardly projecting ribs 20. Three further similarly shaped inwardly projecting ribs 20 are also provided on the shorter side walls 14b and 14d. In this embodiment each of the ribs 20 has a substantially identical shape, although in other embodiments this need not necessarily be the case. In addition, the number of ribs may be changed.

Each rib 20 extends generally vertically from a location near the top of the side wall downwardly so as to merge into the base wall 12. At their upper extent, the ribs terminate in a step 22 that extends around the entire perimeter of the side walls 14a-14c slightly below the lip 16.

When viewed in cross section each rib 20 comprises a straight crest 24 and straight sides 26 that extend from the crest 24 at an included angle of approximately 135° and into the corresponding wall 14a, 14b, 14c or 14d. The dimension of the sides 26 increases towards the lower extent of each rib 20, whereas the dimension of the crest 24 reduces towards the lower extent, as a function of the inward depth of the rib increasing closer to the base wall. In this embodiment each rib 20 has a total width of 7mm, with the crest 24 being 7mm wide at the top of the rib, reducing to 5.1mm at the bottom. The spacing between adjacent ribs is 18mm except where an outwardly projection rib is present (see below), where the spacing is increased to around 27mm

At the perimeter of the base wall 12, where the base wall meets the side walls 14a to 14d, a downwardly projecting bead 28 extends from the base wall so as to form a ridge on the lower face of the base wall and a depression on the upper face of the base wall. The bead 28 has a substantially constant width and depth around the perimeter. It is desirable that the width is minimised as this has been found to reduce the tendency of the bead to flex. Typically a bead width of between 5mm and 8mm is achievable within the manufacturing limitations of the pressing process.

The ribs 20 intersect with the bead 28 and thereby define a discontinuity in the bead 28. In this embodiment, the side walls 14a-14d curve inwardly to merge into the base wall and the ribs 20 similarly curve inwardly so as to meet the base wall 12. In doing so the ribs 20 create the discontinuity 25 in the form of an interruption in the bead 28. This interruption reduces the depth of the depression in the upper face of the base wall 12. In other words a step is introduced into the otherwise constant profile of the depression of the bead 28.

Specifically, in this embodiment, a continuous planar surface 30 is provided on the base wall 12 concentrically within the bead 28 and the discontinuity is substantially at the same level as the continuous planar surface 30.

It has been found that this arrangement of rib and bead increases the strength of the tray 10 both in terms of lateral or side impacts or loads, as well as crush loads from above, e.g., by stacking of trays on top of each other or other loads from above. As such, this enables a given gauge of aluminium sheet to have greater strength or the gauge to be reduced whilst maintaining the strength. In addition the ribs and bead are not of such dimensions that they act as a trap that makes it difficult for foodstuffs to be removed from the tray. Further, the increase in strength/gauge reduction is achieved without compromising the ability of the trays to be manufactured in a high speed pressing operation without tearing - i.e. the ribs and bead are shaped such that the risk of tearing is minimised.

For example, with trays of this type, it is important that a sleeve can be wrapped around the base and held in place in a mechanised process. Such sleeves are used to provide product and marketing information to be viewed by an end user of the foodstuffs. This requires the tray not to distort when filled with foodstuffs, otherwise alignment of the sleeve may be compromised and the mechanised wrapping may fail. Further, the wrapping operation places the sleeve into tension so it is frictionally held on to the tray. This generates a combination of compressive forces on the walls of the tray, and bending forces in the side walls that the sleeve wraps around. The ribs and bead described above have in particular been found to inhibit deformation of the tray during this filling and wrapping operation.

A central region of the base wall is defined inwardly of the continuous planar surface 30 and at least two further impressions are formed in the base wall 12 within this central region. In this embodiment, the impressions are formed to substantially the same depth as the bead 28 with respect to the continuous planar surface 30, but this need not be the case. In this embodiment, the difference in height between the impressions and the continuous planar surface 30 is around 1mm.

In this embodiment ten such impressions are provided and three different shapes of depressions are formed within the central region. Firstly, arranged about a mid-point of the base wall are two hexagonal impressions 32. Outside of the hexagonal impressions 32 along the longer sides of the tray two chevron shaped impressions 34 are provided on opposing sides of the hexagonal impressions (four chevrons in total). The chevron impressions 34 'point' outwardly away from the hexagonal impressions. Between adjacent hexagonal and chevron impressions 32, 34 are corresponding central ridges 36 that are at the same level as the continuous planar surface 30.

The central region further comprises four generally triangular shaped impressions 38 proximate each corner where the walls meet which follow the profile of the truncated corners. These triangular impressions 38 enable further central ridges 36 to be provided in the base wall 12. In this embodiment, each of the hexagonal impressions 32 and chevron impressions 34 has the same width (6.6mm) and each of the central ridges 36 therebetween also have the same dimensions (6.8mm) including the slopes joining each impression and ridge. Finally, at the centre of the base wall 12 is a hexagonal portion 37 within one of the hexagonal impressions 32, which is also at the same level as the continuous planar surface 30. In this embodiment, the hexagonal portion is stamped with indicia relating to the tray (e.g. indicating that the tray is recyclable).

It will be appreciated that since the chevron impressions 34 and central ridges 36 are all of equal width, and align with the hexagonal impressions 32 i.e. each ridge and impression includes two straight portions that intersect at an included angle of 120°. The angle is aligned laterally with a corresponding vertices of the hexagonal impressions 32.

It has been found that such an arrangement of impressions and corresponding ridges thereby formed increases the stability of the base so as to inhibit the sagging thereof when loaded with foodstuffs. The particular shape has been found to inhibit sagging both in the direction between side walls 14a and 14c, as well as between side walls 14b and 14d.

In addition to the inwardly extending ribs 20, the side walls 14a and 14c may further include at least two outwardly extending ribs 40 on each side. The outwardly extending ribs 40 are similarly shaped in cross section to the inwardly extending ribs 20 but do not extend into the bead 28. Rather, the outwardly extending ribs 20 terminate above the bead 28. Whilst these ribs 40 will further impart rigidity to the side walls, their primary function is to hold the wrap-around sleeve on to the tray when it is packaged with foodstuffs so the sleeve does not slide off the tray 10. By providing such outwardly extending ribs this may allow the tension on the sleeves to be reduced whilst ensuring the sleeves do not slide off, further ensuring the integrity of the tray is maintained.

With reference to Figures 4 and 5 a tray 110 of another embodiment is illustrated in isometric and plan view respectively. In this embodiment similar parts are labelled by the same reference numerals but with the addition of the prefix 1. Only differences with the first embodiment are discussed in detail.

In this embodiment it can be seen that the tray 110 comprises two substantially straight side walls joined by semi-circular end walls. The tray 110 has generally longer and narrower proportions in plan view than the tray 12 of the first embodiment. As a consequence, the base wall 112 of this embodiment comprises a single hexagonal depression 132 rather than two as in the first embodiment. In addition, the impressions 138 proximate the curved side walls 114b and 114d are no longer triangular but rather have one straight side proximate the adjacent ridge 136 and curved profiles that correspond to the adjacent the end walls. No ribs are provided on the curved side walls. Further, the ribs 120 provided in the straight side walls 114a and 114c have a short upper tapered section and a constant depth section for the majority of their height. Finally, in this embodiment the straight side walls comprise four outwardly facing ribs 140 per side rather than the two of the first embodiment with alternating inwardly and outwardly extending ribs 120 and 140 respectively.

A further embodiment is illustrated in Figures 6 and 7 in which like parts are labelled by the same numerals but with the addition of the prefix 2. Figures 6 and 7 illustrate a smaller rectangular tray 210 by comparison with Figures 1, 2, and 3. As such in order to maintain the beneficial base arrangement, the base wall 212 comprises a total of two chevron impressions 234 and instead of hexagonal impressions bounded internally by a hexagon that is co-planar with the continuous planar surface 230 as in the previous embodiments, a complete hexagonal central depression is instead provided. Three inwardly facing ribs 20 are provided on the shorter side walls 214b and 214d, but are more closely positioned together than in the first embodiment. The longer side walls 214a and 214c are only provided with three inwardly facing ribs 220 each, with two outwardly extending ribs 240 provided therebetween.

Figures 8 and 9 show a larger tray 310 according to another embodiment. Similar parts are denoted by like numerals, but with the addition of the prefix '3'. In this embodiment the length of the longer side walls 314a and 314c are closer in length to those of the shorter side walls 314b and 314d (i.e. the tray 310 is closer to having a square footprint). As such, in this embodiment three hexagonal impressions 332 are provided with the central impression being unbounded by an inner ridge (similar to the immediately preceding embodiment). Further, only one chevron impression 334 is provided on each side of the outer hexagonal impression 332 and the width dimensions of the impressions

338 and corresponding central ridges 336 are increased compared with those of the other embodiments.

Figures 10, 11 and 12 illustrate a further embodiment of the present invention in which the tray is circular rather than having at least two straight side walls. Like parts are illustrated by like reference numerals but with the addition of the prefix 4.

In this embodiment, in order to optimise the strength of the base, a single hexagonal impression 432 is combined with six chevron impressions 434 that are arranged so as to face towards a centre of the base wall 412 rather than away from the base wall as in the other embodiments. Additionally, ratherthan the hexagonal impression 432 being discrete from the chevron impressions 434, the chevrons merge into the hexagonal impression.

In this embodiment no bead and no continuous planar surface are present. The central ridges 436 are hexagonal and triangular shapes.

Further, in this embodiment the generally vertically arranged ribs are not provided, and instead two additional horizontal steps 422 (three in total) are provided in the side wall 414 in order to strengthen the side wall. An advantage of this arrangement is that the trays 410 can be stacked one on top of each other without requiring angular alignment to properly nest the trays within each other. In other embodiments where ease of nesting is less of a consideration, the circular tray may however be provided with vertical ribs instead of, or in addition to one or more steps.

Figures 13, 14, 15 and 16 present experimental results from crush or tensile strength testing. The figures plot force applied to the tray against displacement (i.e. deformation of the tray). Test results for the tray of the embodiment of figures 1, 2 and 3 are displayed as solid lines. Test results for a similar sized tray of the prior art (an equivalent existing tray produced by the present applicant under the designation AS221000) are displayed as dotted lines. It should additionally be noted that the prior art tray has a thickness that is approximately 10pm thicker than the embodiment of figures 1, 2 and 3.

Figure 13 presents experimental results from crush testing along the long edge of the tray. The embodiment of figures 1, 2 and 3 requires more force to be applied to achieve a displacement of 30mm than the tray of the prior art. This indicates a better crush strength along this dimension.

Figure 14 presents experimental results from crush testing along the short edge of the tray. The embodiment of figures 1, 2 and 3 requires more force to be applied to achieve a displacement of 30mm than the tray of the prior art. This indicates a better crush strength along this dimension.

Figure 15 presents experimental results from crush testing from the top of the tray. The force required to achieve a displacement of 20.3mm is similar for the tray of the prior art, and the embodiment of figures 1, 2 and 3. This indicates a similar crush strength along this dimension. However, as the tray of the prior art is thicker than the embodiment of figures 1, 2 and 3, this shows that the tray of the embodiment of figures 1, 2 and 3 is able to achieve a similar level of strength with a lower material usage.

Figure 16 presents experimental results from tensile strength testing along the long edge of the tray. The embodiment of figures 1, 2 and 3 requires more force to be applied to achieve a displacement of 40mm than the tray of the prior art. This indicates a better tensile strength along this dimension.

It will be appreciated that numerous changes may be made within the scope of the present teachings. For example, the number, size and position of the inwardly and outwardly projecting ribs may be adjusted as required, as may the shape, number and position of the impressions in the base. In addition the overall dimensions and proportions of the trays as a whole may be adjusted.

Claims

1. An aluminium foil tray, comprising:

and wherein:

2. An aluminium foil tray, comprising:

at least one side wall; and a base wall comprising at least three impressions;

and wherein:

3. The tray of claim 1 or claim 2 wherein the side wall further comprises an inwardly projecting rib, and wherein the at least one rib comprises in profile a flat crest of the rib.

4. The tray of claim 1 or claim 3 wherein the at least one rib comprises in profile flat sides of the rib.

5. The tray of claim 4 wherein the sides have an included angle of between 155° and 115° with respect to the crest, preferably 145° and 125°, more preferably around 135°.

6. The tray of any of claims 1 or 3 to 6 wherein the rib tapers into the side wall towards an upper end of the rib.

7. The tray of any of claim 1 or claims 3 to 6 when dependent upon claim 1 wherein the rib curves inwardly to intersect with the bead.

8. The tray of claim 1 or claims 3 to 7 when dependent upon claim 1, wherein the width of the bead is between 5mm and 8mm.

9. The tray of any preceding claim, wherein the tray comprises four side walls, at least two walls each comprising at least one substantially vertically arranged and inwardly projecting rib.

10. The tray of claim 9, each wall comprising at least one substantially vertically arranged and inwardly projecting rib.

11. The tray of any preceding claim wherein the base wall concentrically within the bead is a planar surface at substantially the same level as the discontinuity and connected therewith, preferably wherein the planar surface is continuous around the full length of the bead.

12. The tray of claim 11 wherein a central region is defined inwardly of the planar surface

13. The tray of any preceding claim wherein the base wall comprises a planar surface and at least two impressions at a lower level than the planar surface defining an intermediate ridge having a surface co-planar with the planar surface.

14. The tray of claim 13 wherein the impressions are non-linear.

15. The tray of claim 14 wherein the impressions comprise two straight portions arranged at an angle to each other.

16. The tray of claim 15 wherein an included angle between the straight portions is between 100° and 140°, preferably between 110° and 130°, more preferably substantially 120°.

17. The tray of claim 16 wherein the impressions are arranged such that the included angles face a centre of the base wall.

18. The tray of any one of claims 13 to 17 wherein the impressions have a chevron shape.

19. The tray of claims 13 to 18 wherein at the centre of the base wall an impression or surface co-planar with the planar surface has a polygon shape.

20. The tray of claim 19 wherein the polygon is a hexagon.

21. The tray of any one of claims 13 to 20, wherein the base impressions cover at least 30% of the surface of the base.

22. The tray of any preceding claim, wherein the tray comprises a smooth flanged rim around the top of the at least one wall.

23. The tray of any preceding claim, wherein the tray comprises four side walls, and wherein the upper rim of the tray comprises rounded corners between adjacent walls.

24. The tray of any preceding claim, wherein the thickness of the aluminium foil is between 0.08mm and 0.2mm.

24. The tray of any preceding claim, wherein the tray comprises at least one rib arranged substantially vertically, wherein the at least one rib projects outwardly.

25. The tray of any preceding claim, wherein the thickness of the aluminium foil is between 0.08mm and 0.2mm, optionally between 0.08 and 0.15mm.

Amendments to the claims have been filed as follows

1 06 19

1. An aluminium foil tray, comprising:

5 at least one side wall comprising at least one substantially vertically arranged rib; and a base wall comprising a bead around the outer perimeter thereof, the bead projecting downwardly so as to form a ridge on the lower face of the base wall and a depression in the upper face of the base;

10 the base wall and at least one side wall being configured to define a chamber for containing material to be stored;

and wherein:

the at least one rib projects inwardly so as to form a ridge on an inner face of the at least one side wall and a depression on an outer surface 15 of the at least one side wall;

the at least one rib intersects with the bead, defining a discontinuity in the bead; and the width of the bead is between 5mm and 8mm.

2. The tray of claim 1 wherein the at least one rib comprises in profile a flat crest of the rib.

25 3. The tray of claim 2 wherein the at least one rib comprises in profile flat sides of the rib.

4. The tray of claim 3 wherein the sides of the rib have an included angle of between 155° and 115° with respect to the crest

5. The tray of any preceding claim wherein the rib tapers into the side wall towards an upper end of the rib.

6. The tray of any preceding claimwherein the rib curves inwardly to intersect with

35 the bead.

7. The tray of any preceding claim, wherein the tray comprises four side walls, at least two walls each comprising at least one substantially vertically arranged and inwardly projecting rib.

8. The tray of claim 7, each wall comprising at least one substantially vertically arranged and inwardly projecting rib.

9. The tray of any preceding claim wherein the base wall concentrically within the bead is a planar surface at substantially the same level as the discontinuity and connected therewith.

10. The tray of claim 9, wherein the planar surface is continuous around the full length of the bead.

11. The tray of claim 10 wherein a central region is defined inwardly of the planar surface

12. The tray of any preceding claim wherein the base wall comprises a planar surface and at least two impressions at a lower level than the planar surface defining an intermediate ridge having a surface co-planar with the planar surface.

13. The tray of claim 12 wherein the impressions are not in the shape of a straight line.

14. The tray of claim 13 wherein the impressions comprise two straight portions arranged at an angle to each other.

15. The tray of claim 14 wherein an included angle between the straight portions is between 100° and 140°

16. The tray of claim 15 wherein the impressions are arranged such that the included angles face a centre of the base wall.

17. The tray of any one of claims 12 to 16 wherein the impressions have a chevron shape.

18. The tray of claims 12 to 17 wherein at the centre of the base wall an impression or surface co-planar with the planar surface has a polygon shape.

19. The tray of claim 18 wherein the polygon is a hexagon.

20. The tray of any one of claims 12 to 19, wherein the base impressions cover at least 30% of the surface of the base.

21. The tray of any preceding claim, wherein the tray comprises a smooth flanged rim around the top of the at least one wall.

22. The tray of any preceding claim, wherein the tray comprises four side walls, and wherein the upper rim of the tray comprises rounded corners between adjacent walls.

23. The tray of any preceding claim, wherein the tray comprises at least one rib arranged substantially vertically, wherein the at least one rib projects outwardly.