GB2199235A

GB2199235A - Improvements in or relating to packaging

Info

Publication number: GB2199235A
Application number: GB08724188A
Authority: GB
Inventors: Dominic John Testa
Original assignee: Individual
Current assignee: Individual
Priority date: 1986-10-15
Filing date: 1987-10-15
Publication date: 1988-07-06
Anticipated expiration: 2007-10-15
Also published as: GB8724188D0; GB8624711D0; GB2199235B

Abstract

A package, especially for frozen food, comprises a plate 1 with a plastics film lid 13 supported on a frustoconical 5 which may be of metallised material. The metallised collar protects the outer edges of the food from over-heating drying out in a microwave oven. The package is also suitable for use in conventional ovens. <IMAGE>

Description

"Improvements in or relating to packaging" This invention relates to packaging, and especially to the packaging of food. The food may be frozen or chilled food in packages in which the food can be cooked or heated, and the invention relates especially to a food package which can be heated either in a conventional gas or electric oven or in a microwave oven, to such a package for frozen or chilled food, and to such a package in which the food is presented in the form of a meal or a prepared dish presented on a plate-like receptacle.

It is already known to present frozen or chilled food in the form of a meal or prepared dish on a plate. It has been proposed to present the food on a plate of aluminium foil with a lid of aluminium foil or other material, and whilst such a plate can be heated in, for example, a conventional oven it cannot be heated in a microwave oven because the metal foil tends to shield the food from the microwaves and may interfere with the operation of the oven. In order to overcome this disadvantage, it has been proposed to present the food on a plate of heat-resistant plastics material or moulded fibre lined with heat-resistant plastics material and covered by a lid of heatresistant plastics film. However, there are problems in presenting such a package attractively because either the lid presses down on the food or, if the lid is package and may become unsightly and unattractive.

Furthermore, when such a package is heated in a microwave oven the edges of the food may dry up and become unattractive. That is particularly the case where the food is presented with a gravy or sauce which then forms an unsightly dried ring surrounding the food.

The invention provides a package comprising a plate-like receptacle, an upstanding collar surrounding the contents of the receptacle, and a lid of film covering the contents and the collar, and secured to an edge portion of or under the receptacle.

The upstanding collar is not necessarily verticalsided, and is advantageously frustoconical with its sides sloping inwards towards the top, preferably with a cone half-angle in the range of from 100 to 250 The collar is advantageously of metallised plastics material or metallised paper or board so as to control the microwave heaving of the package contents, such as chilled, frozen, or other food. In any event, a collar material having little or no wicking action towards the contents of the package and/or having an impermeable facing is preferred.

The invention also provides a member for forming the said collar of a package according to the invention. The collar may be a collar for use in the packaging of frozen or chilled food which is to be subsequently re-constituted by the application of heat, and the collar is then advantageously composed of metal foil or of metallised plastics material or metallised paper or board. Preferably, the collar is in the form of an elongate member, the ends of which will be joined together in use.

The invention further provides a package of frozen or chilled food, comprising a plate-like receptacle formed of a heat-resistant plastics material or of a moulded fibre material lined with a heat-resistant plastics material, an upstanding collar of metal foil or metallised paper or board surrounding the contents at or near the edge of the receptacle and a lid of heat-resistant plastics covering the contents of the package and the collar and secured to the edges or underside of the receptacle.

In order to heat or cook the contents of the package, use can be made either of, for example, a conventional oven or of a microwave oven. When using a conventional oven, two slits are made in the lid and the package is placed in the oven for the required time. At the end of this time, the lid is removed and peeled off the edges of the plate-like receptacle, the collar is removed and the contents of the package are presented on the plate-like receptacle ready for eating.

When using a microwave oven, the package is merely placed in the oven for the required length of time. The collar - with its metallised surface located on the inside - ensures the right balance of control over the heating or cooking and prevents gravy or sauce from being dried out at the edges, thereby preventing the occurrence of an unsightly ring at the edges of the food. It will be appreciated that if the package is to be heated in a microwave oven the receptacle and the lid should both be at least substantially of electrically non-conductive materials.

The collar may be of such a length that, when removed, it can be placed over the rim of the platelike receptacle (with the metallised surface located on the outside, that is to say, facing upwards) so that the receptacle can then be placed under a conventional grill to brown the contents of the package without charring the edges of the receptacle. In that case, the ends of the collar will overlap one another when the collar is in position in the package.

The receptacle in a package according to the present invention may be disposable and should be of a material that is suitable for the lid-securing method that is to be employed and for any heating to which it is intended to be subjected. Accordingly, the receptacle may be made of heat-resistant plastics material, such as cast polyethylene terephthalate (PET), but is preferably made of porous fibre material, such as moulded fibre pulp, paper, cardboard or fibre board made in conventional manner by moulding fibres deposited by paper-making techniques.Alternatively, the receptacles may be made from bonded wood chips or bonded fibre material provided that the bonding material is capable of withstanding oven temperatures of up to 225 0C. The receptacles could also be made of foamed plastics or fibrous structures of plastics which are capable of withstanding oven temperatures. It will be appreciated that any of the above-mentioned materials for the receptacles may contain fillers that are not undesirably affected by any heating to which the receptacle is intended to be subjected.

If the receptacle is not made of cast or moulded plastics, it is advantageously lined with a lining of a thermoplastic material that is capable of bonding to the material of the receptacle and is capable of withstanding oven temperatures. The lining material may also be capable of melting under heat and pressure to bond to the material of which the lid is made. Suitable lining materials include nylon, and polyesters such as polyethylene terephthalate.

The lid of the package should be of a material that is not undesirably affected by any heating to which the lid is intended to be subjected and, to that extent, should be heat-resistant. The lid is preferabl a polyester film, such as a PET film having a thickness of the order of 12 to 65 micrometres. However, if the package is only to be heated in a microwave oven, then the lid may be made of high-density polyethylene, polystyrene or possibly polyvinyl chloride. In any cast the lid would normally have to be removed before the package is subjected to grilling.

As indicated above, the collar or mask may, if it is to provide microwave heating control, be made of metal foil, such as aluminium foil, but for greater strength or rigidity it is preferably made of metallised paper or board.

The invention also provides a method of forming a package according to the invention, which comprises placing on a plate-like receptacle contents and an upstanding collar surrounding the contents, covering the receptacle with film material, and fastening the film material to an edge portion of the receptacle or under the receptacle. The film material may be heatsealed or otherwise bonded to an upper surface of a rim portion of the receptacle, and is advantageously supplied in a continuous band, side edge portions of which band are pleated, the pleats being allowed to unfold as the lid is formed to facilitate covering of the receptacle. The film material is advantageously supplied in a continuous band that is yieldably guided in such a manner that extra length of material is available to facilitate covering of the receptacle while the band is maintained under tension.

The invention further provides apparatus for forming a package according to the invention, comprising means for receiving a plate-like receptacle having upon it contents surrounded by an upstanding collar, means for supplying film material above the receptacle, and means for bringing the film material into contact with an edge portion of the receptacle and fastening the film material.

The apparatus may comprise a lower die arranged to support the receptacle, an annular upper die arranged to engage the film material and bring it into contact with an edge portion of the receptacle, and means for cutting the film material outside the upper die, and then advantageously comprises means for feeding the film material to the dies and means for pleating side edge portions of the material, the arrangement being such that in operation as the upper die brings the film material into contact with the receptacle the pleats tend to open out to form part of the lid that extends from the collar to the rim portion of the receptacle.

One form of package constructed in accordance with the invention, and a method of and apparatus for making such packages, will now be described by way of example only with reference to the accompanying drawings, in which: Figure 1 is a cross-section through a package of frozen or chilled food; Figure 2 is a plan view of the package shown in Figure 1 prepared for grilling; Figure 3 is a detail of a collar of the package shown in Figures 1 and 2; Figure 4 is a somewhat schematic elevation view of form of apparatus for manufacturing packages as shown in Figures l and 2; Figure 5 is a cross-section taken along the line 4-4 in Figure 4; Figure 6 is a somewhat schematic plan view of part of a second form of apparatus for manufacturing packages as shown in Figures 1 and 2; and Figure 7 is a view similar to Figure 6 of a third form of apparatus for manufacturing packages as shown in Figures 1 and 2.

Referring to the drawings, and initially to Figure 1, one form of package of frozen or chilled food comprises a plate-like receptacle 1 formed of moulded fibre pulp and lined with a film of polyethylene terephthalate (PET). It is preferred to use "virgin" material in the composition of the plate, since by using such material, there will be no or fewer problems with absorption, taint, and so on. Instead, the receptacle 1 may be formed from a PET material, for example, as used in the food trays sold by BXL Plastics Limited under the trade mark "Multipet". Presented on the plate is a frozen or chilled meal comprising, for example, meat 2, vegetables 3, and sauce or gravy 4.

A collar 5 extends around the edge of the base of the plate-like receptacle 1 and is inclined inwardly of the edge of the receptacle. The height of the collar 5 is about twice the depth of the receptacle 1 from its rim 6 to its base, but the height may be varied in dependence upon the heating or cooking balance required in a microwave oven. The collar 5 is preferably made from a member consisting of a strip of metallised cardboard in the shape of an arc of a disc annulus.

Referring to Figure 3, the member for the collar 5 is provided with a tongue 7 at one end and one or more tongue-receiving slots 8 near the other end, such that the tongue may be engaged in a selected slot so as to secure the ends of the collar. As shown in Figure 3, the tongue 7 is round-tipped and is narrower than the collar 5, with shoulders 9 either side of its base extending along a radius of the annulus, and at the radially outer side of the tongue a radial cut 10 extends the line of the shoulder slightly into the base of the tongue. The slot 8 has end portions 11 angled towards the end of the collar 5, and the distance between the tips of the end portions 11 is equal to the width of the tongue 7. At the radially inner side, a short slot portion 12 extends from the tip of the end portion 11 lengthwise towards the end of the collar 5.

When the tongue 7 is inserted into the slot 8, the slot tends to gape apart, pivoting about a line joining the tips of the outer end portion 11 and of the slot portion 12, facilitating the insertion of the tongue into the slot, while the tip of the outer end portion tends to catch on the cut 10 and to eliminate play in the connection between the tongue and the slot. Other forms of tongue and slot may be used instead.

The cardboard material of the collar 5 is preferably bleach board or similar material with low wicking action, and one preferred material for the 2 collar is a laminate of 330 g/m bleach board, 15 to 20 g/m2 polyethylene, and 0.007 mm aluminium foil. The polyethylene layer serves to bond the aluminium to the board, and acts as a moisture barrier. It has been found, however, that cardboard materials with a higher wicking action, such as folding box board, are acceptable in practice because the metallisation effectively prevents liquids in the food from penetrating the cardboard. The use of a laminated collar is preferred because that gives strength to the collar.

The collar 5 is disposed with the meal inside it and with its metallised face inwards towards the meal.

The collar 5 may have its lower, outer edge either on the base of the receptacle 1 or part of the way up the steep side portion between the base and the rim 6. In the latter case, the collar 5 may be seated on a ledge or corrugation formed in the side portion of the receptacle 1.

The member forming the collar 5 may have two or more slots 8, so that identical members can be used to form collars for receptacles 1 of varying sizes.

The package is covered with a lid 13 of film material, which may be PET film having a thickness in the range of 12 to 65 micrometres, and which is heatsealed under heat and pressure to the PET of the receptacle 1 at the rim 6 of the receptacle. Whilst the bond between the lid and the rim 6 of the receptacle should be sufficiently strong to prevent inadvertent destruction of the seal in normal handling, the bond should preferably be peelable when it is desired to remove the lid from the receptacle, so that no unsightly ring of the film 13 is left on the plate, as might occur if the lid had to be cut off. The polyester material may be that sold by Du Pont under the registered trade mark 'Mylar' , type 100 XM-833 (100 OL), or that sold by ICI under the trade mark 'Melinex', type 850.Each of those films is believed to consist of PET film with a heat-seal coating.

Especially preferred, however, is the film material produced by Etimex Kunststoffwerke GmbH and sold in the U.K. by BXL Plastics Limited under the trade mark "Lamiseal". That film, which is described as comprising a heat-sealable plastics material co-extruded with lowdensity polyethylene film and laminated with polyester film, has been- especially developed for use with PET containers, and is found to give a desirable balance between bond-strength and peelability.

As shown in Figures 1 and 2, the completed package has the film lid 13, under tension, extending across the top of the collar 5 and sloping downwards outside the collar to the rim 6 of the receptacle 1. Because of the relative heights of the collar 5 and the meal, the lid 13 does not touch the meal, and protects the meal against contact or pressure from above.

In order to heat or cook the contents of the package, use may be made of, for example a conventional gas or electric oven, or of a microwave oven. In the use of a conventional oven, the user merely punctures the lid 13, for example, by making two slits in it, to allow for escape of steam, and places the package in the oven. In the use of a microwave oven, the package is placed in the microwave oven and the metallised collar 5 so controls the heating of the contents of the package, by shielding the portions of the food immediately inside it from the effects of the microwaves to some extent, that the tendency of the sauce or gravy 4 at the edge of the base of the receptacle to be dried up by the heating is reduced, so that when the lid and collar are removed, the contents are presented in an attractive manner.The outer surface of the collar 5 acts as an insulator - and incidentally helps to prevent arcing - whilst the metallised surface also acts as a heat reflectant.

If the contents of the package are such that after heating in the microwave oven they require browning, then the lid 13 and collar 5 may be removed and the receptacle placed under a grill to brown the contents.

In that case, the member forming the collar 5 may be made longer than the outer circumference of the rim 6 of the receptacle 1, and provided with an additional slot 8 suitably positioned that the ends of the collar can be joined to form a ring that will overlap the rim 6. The collar 5 may then be placed over the rim 6, with its metallised surface outwards and upwards, during grilling. The metallised surface will then reflect the radiant heat from the grill away from the rim 6 and tend to prevent the rim from becoming charred during grilling. It will be appreciated that, if the member forming the collar 5 is long enough to go right round the rim 6, the collar must be done up with considerable overlap using a different slot 8 in its initial position between the base of the receptacle 1 and the lid 13.

As an example of suitable dimensions for the package, the receptacle 1 may have a diameter of 22 cm overall, 19 cm across the inside of the rim 6, and 16 cm across the base, and a height of 2 cm from the base to the rim. The collar 5 may have a width of 3 cm, an inside radius of 30 cm when laid flat, and an outside (bottom) diameter of 17 to 17.5 cm when assembled, and curve through an arc of 900 when laid flat. The collar may then sit part of the way up the side of the receptacle 1, giving the completed package a height of between 3 and 3.5 cm.

Although a collar with approximately the proportions indicated in the last paragraph, forming a frustum of a cone with a half-angle of about 15 , is preferred, it has been found that cone half-angles in the range of from about 100 to about 250 are satis factory for the package shown in Figures 1 to 3. Lower angles lead to an almost cylindrical collar 5 that tends to buckle easily, and may result in the portion of the lid 13 outside the collar sloping downwards so steeply that the tension in the lid material can lift the rim 6 out of shape. Higher angles lead to a flat collar that tends to crush easily under vertical loads and to overhang the contents of the package, and the strips of, for example, cardboard for such collars cannot be cut from a flat sheet without an amount of wastage that tends to increase with the cone angle.

Although the package shown in the drawings is based on a conventional dished plate with a frozen meal on it, the solid parts of the meal being held in place by frozen sauce or gravy, the package may also be used for other contents, including foods that would have to be kept upright in storage but for which the film lid 13, supported above the surface of the food by the collar 5, would still be advantageous.

Instead of the fairly deeply dished receptacle 1 with a rim 6, other shapes of receptacle could be used, although a completely flat receptacle might not be sufficiently rigid for some purposes unless it was made of a cellular or corrugated material.

Referring now to Figures 4 and 5, one form of apparatus for producing packages according to the invention comprises a filling line 14 where the meal is assembled on the receptacle 1, a station 14a at which the collar 5 is placed on the receptacle, and a lidding station 15. The filling line 14 may be conventional and in the interests of brevity is not described in detail. The station 14a may consist of a station at which a person can assemble the collars 5 and place them manually on the receptacles. It may be desirable for the station 14a to be before the last step of the filling line 14 if that last step comprises pouring on a sauce or gravy that may run up to the collar 5.

The lidding station 15 comprises a reel 16 for lidding film 17 that runs between a heated upper die 18 and a lower die 19 to a take-up reel 20. The receptacles 1 are conveyed between the upper and lower dies 18 and 19, under the.lidding film 17, and when a receptacle is in the correct position the lower die 19 is raised, pressing the film 17 and the rim 6 of the receptacle against the upper die 18, which heats the film to seal the film lid 13, which is thereby formed, to the receptacle. At the same time, the film 17 is cut round the outside of the receptacle 1, by a cutter attached to the upper die 18, to separate the lid 13 from the waste which passes to the take-up reel 20.

Those features of the lidding operation are well known in connection with conventional ovenable food packaging and in the interests of conciseness the means of carrying them out, which may be conventional, are not described in detail.

In order to form the package shown in Figures 1 and 2, however, it is necessary to provide extra film 17 under tension to form the draped portions of the lid 13 outside the collar 5. At the sides of the band of film 17, guides and rollers 21 form pleats 22 in the film before it reaches the dies 18 and 19. At the ends, the reels 16 or 20 are so arranged that they can turn slightly under the action of tension in the band, releasing the extra length of film needed without allowing the band to go slack. Instead, the band may be diverted over a spring-loaded roller 23 between the reel 16 or 20 and the dies 18 and 19.

With a lidding station 15 as shown in Figures 4 and 5, it has been found possible to lid one package every two to three seconds, or 1200-1800 packages per hour. If the filling line 14 and 14a works at a faster rate, two lidding stations 15 may be provided, acting simultaneously and each lidding half of the packages on the line.

Referring to Figure 6 of the drawings, instead of a lidding station 15 arranged in line with the filling line 14 and 14a, there may be provided a rotary table 24 having at two diametrically opposite positions holders 25 in which a receptacle 1 can be placed. In use, an operative takes a filled receptacle from the line 14 and 14a and places it in one holder 25. The table 24 then revolves through 1800, bringing the receptacle 1 into position at a lidding station 26 which is substantially the same as the lidding station 15 shown in Figures 4 and 5, except that the lower die 19, which is formed by the holder 25, is fixed and the heated upper die 18 descends into engagement with it.

In the interests of conciseness the lidding station 26 is not described in more detail. The table 24 then revolves through another 1800, bringing the lidded package back to the operative, who removes the package from the table and replaces it with a filled receptacle for lidding. Because the rotary table 24 has two holders 25, the operative can be removing and replacing one package while the next is being lidded.

Referring now to Figure 7 of the drawings, in order to obtain a higher rate of lidding than that of the arrangement shown in'Figure 6, a rotary table 27 may be provided with eight holders 28a to 31a and 28b to 31b arranged in four pairs evenly spaced around the periphery of the table. In use, the table 27 rotates in 900 steps. At a first position, an operative takes filled receptacles two at a time and places them on the table 27 in one pair of holders 28a and 28b. At the second position a lidding station 32a, similar to the lidding station 26 in Figure 6, lids the receptacle in the trailing holder 29a; the receptacle in the leading holder 29b is inaccessible because of the bulk of the lidding station 32a. At the third position a lidding station 32b lids the receptacle in the leading holder 30b, while the lidded package in the trailing holder 30a rests. At the fourth position another operative removes the lidded packages from both holders 31a and 31b. It will be seen that, because the receptacles in the trailing holder 29a of one pair and the leading holder 30b of another pair can be lidded simultaneously, the arrangement shown in Figure 7 can lid receptacles at twice the rate of an equivalent arrangement as shown in Figure 6.

Claims

What we claim is:

1. A package comprising a plate-like receptacle, an upstanding collar surrounding the contents of the receptacle, and a lid of film covering the contents and the collar, and secured to an edge portion of or under the receptacle.

2. A package as claimed in claim 1, wherein the receptacle has a raised rim and the collar stands up above the rim.

3. A package as claimed in claim 1 or claim 2, wherein the collar is frustoconical with its sides sloping inwards towards the top.

4. A package as claimed in claim 3, wherein the frustoconical collar has a cone half-angle in the range of from 10 to 250.

5. A package as claimed in any one of claims 1 to 4, wherein the collar is formed from an elongate strip of material the ends of which are joined together.

6. A package as claimed in any one of claims 1 to 5, wherein the collar is formed of metal or of a metallised plastics material or metallised paper or board.

7. A package as claimed in any one of claims 1 to 6, wherein the receptacle is disposable.

8. A package as claimed in any one of claims 1 to 7, wherein the receptacle is made of porous fibre material, bonded wood chips, or bonded fibre material, optionally with a plastics lining, or of cast, moulded, or foamed plastics material.

9. A package as claimed in any one of claims 1 to 8, wherein the lid is of coated plastics film heatsealed to the edge portion of the receptacle.

10. A package as claimed in any one of claims 1 to 9, wherein the contents are food.

11. A package as claimed in claim 10, wherein the food is chilled or frozen.

12. A package as claimed in claim 10 or claim 11, wherein the contents consist essentially of a meal presented on the receptacle as a plate.

13. A package as claimed in any one of claims 10 to 12, the materials of which are sufficiently heatresistant for the food to be cooked or heated in an oven in the package.

14. A package as claimed claim 13 which may be heated in a conventional oven or a microwave oven to heat or cook the food.

15. A package substantially as hereinbefore described with reference to, and as shown in, Figures 1 to 3 of the accompanying drawings.

16. A set of parts for a package as claimed in any one of claims 1 to 15, comprising a receptacle, a member for forming a collar, and film material for forming a lid.

17. A member for forming the said collar of a package as claimed in any one of claims 1 to 15.

18. A method of forming a package as claimed in any one of claims 1 to 15, which comprises placing on plate-like receptacle contents and an upstanding collar surrounding the contents, covering the receptacle with film material, and fastening the film material to an edge portion of the receptacle or under the receptacle

19. A method as claimed in claim 18, wherein the film material is heat-sealed or otherwise bonded to an upper surface of a rim portion of the receptacle.

20. A method as claimed in claim 19, wherein the film material is supplied in a continuous band, side edge portions of the band are pleated, and the pleats are allowed to unfold as the lid is formed to facilitate covering of the receptacle.

21. A method as claimed in claim 19 or claim 20, wherein the film material is supplied in a continuous band that is yieldably guided in such a manner that extra length of material is available to facilitate covering of the receptacle while the band is maintaine under tension.

22. A method of forming a package, substantially as hereinbefore described with reference to the accompanying drawings.

23. Apparatus for forming a package as claimed i any one of claims 1 to 15, comprising means for receiving a plate-like receptacle having upon it contents surrounded by an upstanding collar, means for supplying film material above the receptacle, and mean for bringing the film material into contact with an edge portion of the receptacle and fastening the film material.

24. Apparatus as claimed in claim 23, which comprises a lower die arranged to support the receptacle, an annular upper die arranged to engage the film material and bring it into contact with an edge portion of the receptacle, and means for cutting the film material outside the upper die.

25. Apparatus as claimed in claim 24, comprising means for feeding the film material to the dies and means for pleating side edge portions of the material, the arrangement being such that in operation as the upper die brings the film material into contact with the receptacle the pleats tend to epen out to form part of the lid that extends from the collar to the rim portion of the receptacle.

26. Apparatus for forming a package, substantially as hereinbefore described with reference to, and as shown in, Figures 4 and 5 of the accompanying drawings.

27. Apparatus as claimed in claim 26, modified substantially as hereinbefore described with reference to, and as shown in, Figure 6 or Figure 7 of the accompanying drawings.