FOOD COVERING

Abstract

A flexible stretchable food covering or wrapping film that provides an airtight seal when applied to a food item. The film is made of silicone having a thickness in the range 0.15 mm to 0.26 mm, which renders it thin enough to retain its shape in sealing relation to the item being wrapped, while being thick enough to not be readily ruptured in use. A method of storing and cooking food using the film is also disclosed.

Claims

1-17. (canceled)

18. A food covering comprising: a silicone film of at least food grade, adapted for clinging, for resistance to deterioration at temperatures suitable for roasting and baking food and to be substantially transparent, by having a thickness in the range 0.15 mm to 0.26 mm and hardness on the Shore scale in the range Shore A 25-70.

19. The food covering of claim 18 being resistant to deterioration at a temperature of at least 530K.

20. The covering of claim 18 wherein the film comprises silicone rubber.

21. The covering of claim 18, wherein the film has a thickness in the range 0.19 mm to 0.21 mm.

22. The covering of claim 18, wherein the film has a hardness on the Shore scale in the range Shore A 30-50.

23. The covering of claim 18, wherein the film is distinguishable from other single use films by colouring.

24. A method of inhibiting food deterioration, the method comprising the steps of: providing food requiring preservation and a covering comprising a substantially transparent silicone film adapted for clinging by having a thickness in the range 0.15 mm to 0.26 mm and hardness on the Shore scale in the range Shore A 25-70, and wrapping the food in the film, thereby to create by means of the film a substantially airtight barrier around the food.

25. The method of claim 24 including the step of causing the film to be wrapped on to itself for allowing a cling seal to be established between contacting surfaces thereof.

26. The method of claim 24 comprising providing the film on a substrate and removing the film from the substrate prior to application to an item to be wrapped.

27. The method of claim 24 wherein the film comprises silicone rubber.

28. The method of claim 24 wherein the film has a thickness in the range 0.19 mm to 0.21 mm.

29. A method of heating food, the method comprising the steps of: providing food requiring heating and a wrapping that is temperature resistant to a temperature suitable for food roasting or baking, the wrapping comprising a substantially transparent silicone film adapted for clinging and retaining a given wrapped shape, by having a thickness in the range 0.15 mm to 0.2 6mm and hardness on the Shore scale in the range Shore A 25-70; wrapping the food in the wrapping; and subjecting the wrapped food to effective roasting or baking heat.

30. The method of claim 29 wherein the film comprises silicone rubber.

31. The method of claim 29, wherein the film has a thickness in the range 0.19 mm to 0.21 mm.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0035] In order that the invention may be readily understood, and put into practical effect, reference will now be made to the accompanying figures. Thus:

[0036] FIG. 1 shows in schematic form a diagram of a preferred embodiment of the wrapping of this invention ready for use in wrapping a food item.

[0037] FIG. 2 shows the wrapping of FIG. 1 with a food item placed upon it.

[0038] FIG. 3 shows the wrapping of FIG. 1 operatively wrapped around the aforesaid food item.

DETAILED DESCRIPTION OF AN EMBODIMENT OF THE INVENTION

[0039] The food covering of this invention provides a silicone sheet having a combination of hardness and thickness in a limited range that enables it to render improved performance compared with prior silicone films, without the need for it to be merely a layer in a laminated structure. The improvements render the present film on its own not only suitable to take on and retain a given changed shape, such as when sealingly wrapped about food, but also to be subjected to heating conditions, such as those experienced in the process of roasting or baking, without deterioration, for example deterioration in the form of thermally induced disintegration. The wrap is therefore suitable for reuse and advantageously can be washed. When dry, its surfaces tend to cling to other objects as well as to self-adhere.

[0040] The wrapping is re-usable, recyclable and able functionally to replace at once three common single-use items in household use, namely cling film, aluminium foil and baking paper. The covering is composed of a homogeneous, unsupported, sheet of silicone, preferably in the form of silicone rubber. It is unsupported in the sense that it is not bonded or attached to any other layer, such as a substrate at the time of its being applied to an item to be covered. The film functions as a three-in-one wrapping by virtue of its thickness being limited to a narrow range of values from 0.15 mm to 0.26 mm.

[0041] It is found that within the thickness range stipulated below, the film surprisingly exhibits a degree of clinginess and is not effective as a lubricant, as silicone surfaces are recognized to be. When the thickness is above or below the selected range, it is found that contrary to suggestions in the prior art reviewed herein, the desired properties of this invention are not exhibited. Outside the selected range, the role of a backing layer in a laminated structure becomes crucial to the successful functioning of the composite product when being applied in use. The inventor has found this not to be so in the case of the present film, which allows for any substrate or backing sheet used in manufacture to be removed by peeling it away from the silicone film, before the silicone is applied as a covering or wrapping.

[0042] The thickness of the film is in the range from 0.15 mm to 0.26 mm, preferably 0.190 mm to 0.21 mm. Ideally, the thickness is 0.20 mm=/3%. Ideally, it is found that the sheet should, for an optimum combination of wrappability, strength and remaining in clinging adhesion once wrapped, be 0.2 mm thick.

[0043] Wrappability is, without being bound by theory, thought to be a function of hardness and thickness, and adhesion a function of electrostatic properties. If the film is excessively hard, it cannot be bent and moulded to the shape of the item being wrapped. It is found that the film should have a hardness on the Shore scale in the range Shore A 25-70. Further preferably, the hardness should be in the range Shore A 30-50.

[0044] The film needs further to be substantially transparent, so as to facilitate an observer seeing what is inside the wrapping. This is particularly advantageous when the wrapped item is being cooked, such as by baking. The film may be coloured for decorative or functional purposes, such as to exclude or filter specific wavelengths of light. A preferred, but non-limiting, example of colour is 40% Pantone 376. Colour also enables a user to differentiate between this reusable film and prior art films not having this advantage, such as conventional, single-use cling-films made of polyethylene. It also reduces the risk that a user may dispose of the film of this invention by accident. It will be appreciated, therefore, that various colours may be used within the scope of this invention, whether for decorative or functional purposes. However, the stated shade is found to be particularly advantageous as it does not correspond to the colour of the vast majority of baked or roasted foods and therefore can easily be detected and removed for re-use.

[0045] Since the silicone film is to be used with food and is intended to come into direct contact with food, it is necessarily at least of food quality standard. Manufacture of the film is by methods known in the art, using commercially available liquid silicone and limiting the thickness to the above-stated range. The liquid silicone is applied to a substrate of PET that is formulated to be free of bisphenol A (BPA). Ideally the thickness of the silicone layer, when separated from the substrate layer, is 0.20 mm with a 3% tolerance. The silicone layer and substrate are together rolled up onto a roll or cut into discrete sheets to be supplied in standard sheet sizes.

[0046] The silicone is separated from the substrate before being applied to the food item or container to be covered. This reduces the risk that would otherwise exist of tearing the silicone film when in the proposed thickness range, were the substrate to be removed only after application of the film. To assist in separation of the silicone film from the substrate without tearing, the film may be pre-scored or have attached a separation tag, according to conventional methods. Without wishing to be bound by theory, it is believed the absence of BPA from the PET substrate helps avoid unwanted crosslinking with the silicone film that may otherwise promote a propensity for the silicone film to be damaged when being separated from the substrate.

[0047] A silicone film of thickness in the range 0.15 mm to 0.26 mm is found thin enough to be readily wrappable about food or over and around the rim of a food container to provide an airtight seal, while conforming to the profile of the item being wrapped. With this thickness, it remains in shape and maintains an airtight seal for weeks under refrigeration, yet it is thick enough to withstand handling and reasonable use as a wrapping film without rupturing or tearing.

[0048] Referring to FIG. 1, in a preferred embodiment of this invention, a covering, generally denoted by the number 10, is shown laid out in a generally flat manner, ready for an item of food 24 to be placed upon it for wrapping. Covering 10 comprises a transparent silicone rubber film in the form of a sheet 12, having an upper surface 14 and opposite lower surface 16 which has been peeled away from its BPA-free PET substrate, beginning at a location at peripheral portion 20 which extends inwardly from edge 22 to about the broken line 26. The sheet is 0.20 mm thick, having self-adhesive properties, as well as the property that it does not slip from porous and non-porous dry surfaces.

[0049] In FIG. 2, food item 24 is shown placed on sheet 12 in readiness for wrapping.

[0050] In FIG. 3, food item 24 is shown wrapped in transparent cling sheet 12.

[0051] It will be appreciated that instead of having sheet 12 completely wrapping around a food item such as a bread roll or hamburger, so that is in contact with substantially the entire outer surface, the covering is placed over and wrapped around a container in which the food item is held, for example, an open-topped polystyrene tray. It is not necessary for the covering to adhere to the polystyrene, provided the covering itself is self-adhering when, as in the case of the food item in FIGS. 1-3, it is wrapped back over itself, so that at least a peripheral portion 20 of lower surface 16 is brought into contact with upper surface 14.

[0052] The covering of the invention, in addition to being re-usable, has the advantage of being able to replace at least three commonly used single-use items, namely conventional known cling film, aluminium foil and baking paper, providing the user with effective three-in-one product functionality. The specific thickness range found by the present inventor was not previously known to provide the benefits realised by way of the present invention. Prior proposals simply to use a silicone film in a generic form have not been practical, failing to achieve the advantages of the present invention. The silicone film of thickness in the range 0.15 mm to 0.2 6mm is found to be thin enough to be readily wrappable about food or over and around the rim of a container to provide an airtight seal while conforming to the profile of the item being wrapped, remaining in shape practically indefinitely, and is still found to be thick enough to withstand handling and reasonable use as a wrapping film without a propensity to rupture or tear.

[0053] These embodiments merely illustrate examples of the method and covering of the invention providing a multifunctional silicone film. With the insight gained from this disclosure, the person skilled in the art is well placed to discern further embodiments by means of which to put the claimed invention into practice.