GB2546818A

GB2546818A - Process for sealing a container

Info

Publication number: GB2546818A
Application number: GB1601783.2A
Authority: GB
Inventors: Ibbotson Peter; Ibbotson Joe
Original assignee: Four04 Flexibles Ltd
Current assignee: Four04 Flexibles Ltd
Priority date: 2016-02-01
Filing date: 2016-02-01
Publication date: 2017-08-02
Anticipated expiration: 2036-02-01
Also published as: WO2017134431A1; GB201601783D0; GB2546818B

Abstract

A process for making a sealed container comprises: (a) providing a lidding film 8 having adhesive applied to a selected area of one of its surfaces; (b) providing a container 2 comprising a base and continuous side wall extending generally upwards from the base; and (c) applying the lidding film to the container such that the lidding film is sealed to the container. Also claimed is a lidding film for sealing a container, having adhesive applied to a selected area of one of its surfaces. The selected area corresponds to a sealing area between the lidding film and the container. Also claimed is a process for making a lidding film for sealing a container, comprising applying adhesive to a selected area of one of its surfaces, wherein the selected area corresponds to a sealing area between the lidding film and the container. The adhesive may be applied to the lidding film in register with the shape of a flange of the container. The adhesive may be applied by a printing technique such as flexographic printing or by gravure or by digital printing.

Description

PROCESS FOR SEALING A CONTAINER TECHNICAL FIELD

The present invention is directed to a process for making a sealed container, to a lidding film for sealing a container, to a process for making a lidding film for sealing a container, to a sealed container obtainable by the process for making a sealed container, to a manufacturing system configured to carry out the process for sealing a container, and the use of said lidding film in the manufacture of a sealed container.

BACKGROUND OF THE INVENTION

Processes for sealing containers, for example, trays for packaging fresh produce and other foodstuffs are many and various. However, there is an ongoing need to improve packaging efficiencies and properties, reduce waste, reduce cost and improve recyclability of post-consumer waste.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention, there is provided a process for making a sealed container, wherein the process comprises: (a) proving a lidding film having adhesive applied to a selected area of one of its surfaces; (b) providing a container comprising a base and continuous side wall extending generally upwards from the base; and (c) applying the lidding film to the container such that the lidding film is sealed to the container; optionally wherein the selected area constitutes no more than about 10 % of the surface area of the surface of the lidding film to which the adhesive is applied following sealing of the lidding film to the container.

According to a second aspect of the present invention, there is provided a lidding film or sheet of lidding film for sealing a container, the lidding film having adhesive applied to a selected area of one of its surfaces, wherein the selected area corresponds to a sealing area between the lidding film and the container to which it is to be applied.

According to a third aspect of the present invention, there is provided a process for making a lidding film for sealing a container, the process comprising applying adhesive to a selected area of one of its surfaces, wherein the selected area corresponds to a sealing area between the lidding film and the container to which it is to be applied., optionally wherein the adhesive is applied to the lidding film in register, for example, in register with the shape of a flange of the container, optionally wherein the adhesive is applied by a printing technique such as, for example, by flexographic printing or by gravure or by digital printing, or a combination thereof.

According to a fourth aspect of the present invention, there is provided a sealed container obtainable by the process according to the first aspect, or the first and third aspects of the present invention.

According to a fifth aspect of the present invention, there is provided a manufacturing system configured to carry out a process for sealing a container according to the first aspect, or the first and third aspects of the present invention, the system comprising a supply of containers having an opening, a supply of lidding film, a supply of adhesive and apparatus for applying adhesive to the lidding film in a selected area(s) and an apparatus for sealing the lidding film to the container.

According to a sixth aspect, the present invention is directed to the use of a lidding film according to the second aspect of the present invention in the manufacture of a sealed container, for example, a sealed container according to the fourth aspect of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1A is a depiction of an exemplary sealed container in plan view.

Fig. 1B is a sectional view of the container of Fig. 1A through A—-A.

Fig. 2 is a schematic depiction of initial process steps (application of print design, eye mark(s) and adhesive in register) according to one illustrated embodiment.

Fig. 3a is a schematic depiction of a laser perforation and film slitting steps according to one illustrated embodiment.

Fig. 3b is a plan view of the film slitting step of Fig 3a.

Fig. 4 is a schematic depiction of eye-mark registration between the lidding film and containers for sealing step according to one illustrated embodiment.

Fig. 5 is a schematic depiction of the sealing step according to one illustrated embodiment.

Fig. 6 is a schematic depiction of the process post-sealing according to one illustrated embodiment.

Fig. 7a is a plan view of a continuous sheet of film from which the lidding films are formed during the sealing process according to one illustrated embodiment. The dimensions indicated are exemplary and not limiting.

Fig. 7b is an expanded plan view of one of the lidding films depicted in Fig. 7a. The dimensions indicated are exemplary and not limiting.

DETAILED DESCRIPTION OF THE INVENTION

In the following discussion, references may be made to the illustrated embodiments depicted in the Figures. References to the figures are made to illustrate the invention and are not intended to limit the embodiments described below to embodiments having precisely the features depicted in the Figures.

One advantage of the process described herein may be that it is more efficient owing in part to the application of adhesive to only selected areas of the lidding film, such as those which substantially correspond to the sealing area between the lidding film and the container to which the lidding film is to be applied. It is more efficient because less adhesive is required compared to a process in which a blanket of adhesive is applied to the entirety of the lidding film, and therefore less adhesive is required to seal the lidding film to the container. Further, by applying adhesive to the lidding film as opposed to only the container, dwell times, application temperatures and application pressures may be reduced, therefore requiring a lower energy input per container. Lower temperatures may also enable the use of a greater variety of lidding films which would otherwise degrade or stick to sealing heads at higher temperatures. Further advantages may ensue in modified and controlled atmosphere packaging in which the lidding film has tailored properties such as moisture, vapour and/or gas transmission through the film. By applying adhesive to the lidding film in only selected areas, such as those which substantially correspond to the sealing area between the lidding film and the container to be sealed the lidding film, the functional properties of the lidding film are not compromised and, thus, modification and/or control of the atmosphere within the sealed container is likewise unaffected. This is particularly important in the packaging of fresh produce whereby atmospheric conditions within the sealed container can be controlled by varying the barrier properties of the lidding film, for example, its moisture vapor transmission rate and/or gas transmission rate, and/or the properties of the container, in order to extend product shelf life and/or maintain appearance.

Another advantage of the process described herein and the sealed containers made by the process may be improvements in the recycling of containers made of recyclable materials. For example, it has surprisingly been found that by applying the adhesive to the lidding film as opposed to the container, a greater amount of adhesive will be retained on the film as it is peeled-off. This means that a lesser amount of adhesive, if any, will be retained on the container. This in turn improves recycling efficiencies because there is less adhesive to remove from the container in the recycling process. Thus, in certain embodiments, the container is formed of a recyclable material. There will be a similar benefit for biodegradable containers, i.e., if the adhesive is not itself biodegradable there is a reduced need to remove adhesive from the container prior to biodegradation, e.g., compositing. Thus, in some embodiments the container is formed of a biodegradable material.

In one aspect of the present invention, there is provided a process for making a sealed container, wherein the process comprises: (a) proving a lidding film having adhesive applied to a selected area(s) of one of its surfaces; (b) providing a container comprising a base and continuous side wall extending generally upwards from the base; and (c) applying the lidding film to the container such that the lidding film is sealed to the container. In certain embodiments, the selected area or areas constitutes no more than about 80 % of the surface area of the lidding film following application of the lidding film to the container, for example, no more than about 70 %, or no more than about 60 %, or no more than about 50 %, or no more than about 40 %, or no more than about 30 %, or no more than about 25 %, or no more than about 20 %, or no more than about 15 %, or more than about 10 %, or no more than about 5 %, or no more than about 2 %, or more than about 1 % of the surface are of the lidding film following application of the lidding film to the container. By “selected areas” is meant that the adhesive is not applied in blanket fashion over the entire surface of the lidding film, but rather is applied in selected regions under control of the manufacturer, i.e., user-defined areas. In certain embodiments, the process is automated and thus the application of adhesive to the selected area or areas is under computer program control.

In certain embodiments, the adhesive is applied to the lidding film by a guide such that the adhesive corresponds to a sealing area only between the lidding and the container. The guide or guides may be in the form of a registration, e.g., eye-mark, which is applied to the lidding film before application of the adhesive. In certain embodiments, the registration mark or marks is/are applied during the process of sealing the containers. In other embodiments, the application of registration marks is not part of the process of the invention, and is instead applied during manufacture of the lidding film. Preferably, however, the application of the registration marks is a part of the process of the first aspect of the invention. Thus, in certain embodiments, the adhesive is applied to the lidding film in register and corresponds to a sealing area between the lidding film and the container. The registration mark or marks therefore guide the application of adhesive to the selected area or areas. Advantageously, in certain embodiments, no adhesive is applied to the container during the process according to the first aspect of the present invention.

In certain embodiments, the container has a flange formed along the upper edge of the continuous side wall and adhesive is applied to the lidding film such that the lidding film is sealed to the container via the flange only. In certain embodiments, the adhesive is applied as a continuous layer or strip which is substantially in register with the flange. In certain embodiments, the strip or layer is non-continuous. In certain embodiments, therefore, the pattern of adhesive is dictated by the path of the flange about the upper edge of the continuous side wall of the container to be sealed, i.e., the pattern of the adhesive corresponds to or is in register with the flange of the container. The path of the flange is in turn dictated by the shape of the continuous side wall. In plan view (see, for example, Fig. 1a), therefore, the shape of the continuous side-wall may be a square, rectangle, circle, squircle, oblong, ovoid, triangle, diamond, pentagon, hexagon, heptagon, octagon or any other regular or irregular shape, for example, kidney-shaped or bean-shaped. In certain embodiments, in which the shape has corners, the corners may be rounded. The flange will accordingly, in plan view, follow a path corresponding to the shape of the continuous side-wall. Although this section and following sections are described with reference to a flange, the process is applicable to containers having a rim or lip about the about the upper edge of the continuous side wall of the container to be sealed.

The container has an opening which is sealed with the lidding film, i.e., the lidding film bridges across the opening. The side walls extend generally upwards from the base forming an interior housing within the container. In plan view, the periphery of the container may be rectangular, oblong, square, circular, ovular, or a squircle. Corners (e.g., between the base and sidewalls, or between adjacent sidewall sections), if present, may be angular or curved. The side wall generally extends vertically from the base. In certain embodiments, an angle between the side wall and the base is at least 90°, for example, from about 90° to about 120°, or from about 90° to about 110°, or from about 90° to about 100°.

In certain embodiments, the height of the container (i.e., the distance between, and perpendicular to both the base and the plane of the polymeric film) is at least about 5 mm, for example from about 5 mm to about 500 mm, or from about 10 mm to about 400 mm, or from about 15 mm to about 300 mm, or from about 20 mm to about 200 mm, or from about 25 to about 150 mm, or from about 30 to about 120 mm, or from about 30 to about 100 mm, or from about 30 to about 80 mm, or from about 20 to about 60 mm, or from about 20 to about 50 mm, or from about 25 to about 50 mm, or from about 30 to about 50 mm, or from about 35 to about 50 mm, or from about 25 to about 40 mm, or from about 25 to about 35 mm, or from about 30 to about 40 mm, or from about 35 to about 45 mm. The length and width of the container may vary, independently, between about 50 mm and 500 mm.

In certain embodiments, the container is suitable for packaging individual pieces of fresh produce (e.g. fruit, vegetables and/or fungi). In certain embodiments, the tray comprises a plurality of cells for housing individual pieces of fresh produce, including edible and non-edible products.

In certain embodiments, the seal is formed between the lidding film and the flange. In certain embodiments, and with reference to Figures 1A and 1B, a flange (4) extending outwards from, and about, the perimeter of the opening (6) of the container (2), and the seal (3) is formed between the lidding film (8) and the flange (4). The flange (4) may extend outwards, for example, in a plane generally parallel to the base (12) of the container (2). The flange (4) may extend outwards up to about 50 mm from the upper edge of the continuous side wall, for example, 40 mm, or 30 mm, or 20 mm from the upper edge of the continuous side wall, for example, from about 1 mm to about 15 mm, or from about 2 mm to about 12 mm, or from about 2 mm to about 10 mm, or from about 2 mm to about 8 mm, or from about 2 mm to about 6 mm from the upper edge of the continuous side wall. In certain embodiments, flange (4) extends outwards up to about 1 mm, or about 2 mm, or about 3 mm, or about 4 mm, or about 5 mm, or about 6 mm, or about 7 mm, or about 8 mm, or about 9 mm, or about 10 mm from the upper edge of the continuous side wall. As shown in Figure 1A, for example, the flange (4) may be formed about the entirety of the rim of the container (2) at the upper edge of the continuous side wall (14).

In certain embodiments, the one or more selected areas (i.e., the adhesive following application to the lidding film) may cover, in total, up to about 80 % of the total surface are of the lidding applied to the container, for example, up to about 70 %, or up to about 60 %, or up to about 50 %, or up to about 40 %, or up to about 30 %, or up to about 20 %, or up to about 10 %, or up to about 5 % of the total surface of the lidding film applied to the container.

In certain embodiments, the strip or layer of adhesive applied to the lidding film may have a width which is of a certain tolerance of the size of the flange (i.e., the distance by which the flange extends outwards from the upper edge of the continuous side wall). For example, the width of the strip or layer may up to about 500 % greater than the of the size of the flange (and any percentage there between), for example up to about 400 % greater, or up to about 300 % greater, or up to about 200 % greater, or up to about 100 % greater, or up to about 50 % greater. In certain embodiments, the coverage of adhesive of the film by the adhesive does not interfere with the functionally of the film, for example, a film having an MVTR and/or OTR to control or modify the atmospheric conditions within the container when sealed. For example, the width of the strip or layer may be +/- 25 % of the size of the flange (and any percentage there between), for example, +/- 20 % of the size of the flange (and any percentage there between), or +/-15 % of the size of the flange (and any percentage there between), or +/- 10 % of the size of the flange (and any percentage there between), or +/- 5 % of the size of the flange (and any percentage there between, or +/- 2 % of the size of the flange (and any percentage there between), or +/1 % of the size of the flange (and any percentage there between), or +/ 0.5 % of the size of the flange (and an any percentage there between), or +/- 0.25 % (and any percentage there between), or +/- 0.1 % (and any percentage there between). In certain embodiments, the width of the strip or layer of adhesive is greater than the size of the flange. In such embodiments, the lidding film may be applied to the flange such that all of the flange is covered by the adhesive. In certain embodiments, the width of the strip or layer of adhesive is up to about 500 %, greater, for example, up to about 400 % greater, or up to about 300 % greater, or up to about 200 % greater, or up to about 150 % greater, or up to about 100 % greater, or up to about 75 % greater, or up to about 50 % greater, or up to about 25 % greater than the size of the flange, or up to about 20 % greater, or up to about 15 % greater, or up to about 10 % greater, or up to about 5 % greater, or up to about 2 % greater, or up to about 1 % greater, or up to about 0.5 % greater, or up to about 0.25 % greater, or up to about 0.1 % greater. Thus, for example, if the width of the flange is 8 mm, the width of the strip or layer of adhesive may be about 10 mm. In certain embodiments, the width of the strip or layer is substantially consistent along its length, by which is meant that the width of the strip or layer does not vary along its length by more than about 25 %, or by more than about 20 %, or by more than about 15 %, or by more than about 10 %, by more than about 5 %, or by more than about 2 %, or by more than about 1 %, or by more than about 0.5 %. For example, for a variation of no more than about 10 %, if the width of the flange is 10 mm, the width of the strip or layer of adhesive will be between 9 and 11 mm. In certain embodiments, the width of the strip or layer of adhesive is less than the size (i.e., width) of the flange, for example, from 1% to about 99 % of the size of the flange, or no greater than about 95 % of the size of the flange, for example, no greater than about 90 %, or no greater than about 80 %, or no greater than about 70 %, or no greater than about 60 %, or no greater than about 50 %, or no greater than about 40 %, or no greater than about 30 %, or no greater than about 20 %, or no greater than about 10 %. In certain embodiments, the width of the strip or layer of adhesive is at least about 1 % of the size of the flange, for example, at least about 2 %, or at least about 5 %, or at least about 10 %.

In certain embodiments, the lidding film extends beyond the flange, for example, by an amount sufficient for a user to grip and tear or peel back the lidding film in order to access the contents of the container. In certain embodiments, the lidding film comprises a tab portion (10), as shown in Figure 1A. The tab portion may be sized and configured to enable a user to grip the tab and remove, for example, tear or peel back, the lidding film from the container. The tab portion, when present, may be integral to the lidding film.

The adhesive may be applied, preferably in register, by any suitable technique which is capable of applying the adhesive in the one or more selected areas, preferably in register. For example, the layer of adhesive may be applied by spray coating, by a hot melt gun or by a printing technique. Advantageously, the adhesive is applied to the lidding film by a printing technique, for example, by flexographic or gravure or offset printing or digital printing. The flexographic technique includes application of the adhesive to a roller or plate and the like having raised portions corresponding to the size (e.g., width and length) and form/pattern of the adhesive when applied to the lidding film. The adhesive then transfers from the raised portions to the lidding film. The gravure technique includes application of the adhesive to a roller and the like having recessed (e.g., depressed or sunken) portions corresponding to the size (e.g., width and length) and form/pattern of the adhesive when applied to the lidding film. The adhesive then transfers from the recessed portions to the lidding film. Printing the adhesive, for example, by flexography or gravure or by digital printing, promotes the application of the adhesive in a consistent fashion and has flexibility in that the type of, and size (e.g., width, thickness, length) and form/pattern (which will depend on the shape of the container being sealed) of the adhesive may be easily adjusted. Any suitable printing apparatus may be used to apply the adhesive. In certain embodiments, the adhesive is applied by gravure printing. In certain embodiments, the adhesive is applied by a flexographic printing technique. An exemplary apparatus is a Windmoeller & Hoelscher flexographic printing press with an inline gravure system. In certain embodiments, the print design and/or registration marks are applied via a flexographic printing press followed by the application of the adhesive, in register, by gravure printing.

As described herein, the lidding film advantageously has one or more registration marks to guide the application of adhesive to the selected area or areas such that the lidding film may be applied in register to the container, thereby forming a seal between the lidding film and the flange of the container. The registration marks may be of any suitable shape and size provided they are suitably sized and shaped to operate as a registration mark.

In certain embodiments, heat and/or pressure is applied to the lidding film and/or the container to seal the lidding film to the container via the adhesive. As discussed above, applying adhesive to the lidding film may advantageously facilitate the use of lower temperatures and/or pressures than would otherwise be necessary. Heat may be applied from the opposite surface to that which the adhesive is applied. In certain embodiments, therefore, heat is applied from above the lidding film to that which would be the upper surface of the film as it is processed and sealed to the container. In certain embodiments, heat is applied simultaneously with pressure, for example, heat from above the lidding film and pressure from below, for example, as the container is brought up into contact with the lidding film from below the lidding film (such that the flange of the container is brought into direct contact with the adhesive). In certain embodiments, heat only is applied, preferably from above and opposite the surface to that which the adhesive is applied. Additionally or alternatively, heat may be applied from below, i.e., via the underside of the flange of the container. In certain embodiments, pressure only is applied (e.g., a cold-seal process) from below and/or above, preferably from below as the container is brought up into contact from below the lidding film. In a cold-seal process the temperature is typically ambient, e.g., no greater than about 25 °C, or no greater than about 20 °C. In certain embodiments, the temperature during cold-seal is at least about 0 °C, or at least about 2 °C, or at least about 5 °C, or at least about 10 °C, or at least about 15 °C. In such embodiments, the adhesive may be selected so that it seals via the application of pressure-only and in the absence of heat, for example, a pressure-sensitive adhesive such as, but no limited to, adhesive based on a natural rubber latex, or synthetic or hybrid blends thereof. Exemplary adhesives include the PureSeal™ range of cold-seal adhesives available from Ashland.

In certain embodiments, heat is applied to the lidding film and/or the container, preferably to the lidding film (e.g., from above and to the upper surface of the lidding film), at a temperature of up to about 500 °C, for example, no greater than about 400 °C, or no greater than about 300 °C, or no greater than about 250 °C, or no greater than about 200 °C, or no greater than about 175 °C, or no greater than about 150 °C, or no greater than about 125 °C, or no greater than about 100 °C, or no greater than about 90 °C, or no greater than about 80 °C. In certain embodiments, the temperature is at least about 50 °C, for example, at least about 60 °C, or at least about 70 °C, or at least about 75 °C, or at least about 80 °C. In certain embodiments, the temperature is from about 70 °C to about 200 °C, for example, from about 70 °C to about 180 °C, or from about 70 °C to about 170 °C, or from about 70 °C to about 160 °C, or from about 70 °C to about 150 °C, or from about 70 °C to about 140 °C, or from about 70 °C to about 130 °C, or from about 70 °C to about 120 °C, or from about 70 °C to about 110 °C, or from about 70 °C to about 100 °C, or from about 70 °C to about 95 °C, or from about 70 °C to about 90 °C, or from about 70 °C to about 85 °C, or from about 70 °C to about 80 °C. In certain embodiments, the temperature is at least about 25 °C, for example, at least about 30 °C, or at least about 40 °C, or at least about 50 °C, or at least about 60 °C. Heat may be provided via any suitable means, for example, a heat seal or heating jaws. Preferably, the heat is applied via a seal e.g., a sealing shoe or head, which is of substantially the same shape and path of the layer or strip of adhesive and the flange of the container, i.e., so that the application of heat is focussed on the adhesive and not the remaining area of the lidding film which is not part of the seal that is formed between the lidding film and the flange of the container. In certain embodiments the sealing head or shoe matches the shape of the flange of the container which is being sealed.

In certain embodiments, heat is applied to the lidding film at a temperature below that which would cause degradation of the film and/or sticking of the lidding film to a sealing head or heads used during application of the lidding film to the container. As discussed above, however, application of the adhesive to the lidding film (and not the container) may enable sealing at lower temperatures, enabling a greater variety of lidding films to be utilised than would otherwise be possible.

Pressure may be used to fuse the lidding film to the container, for example, at or about its flange, and thereby seal the container. In certain embodiments, pressure is applied by raising the container up to the surface of the lidding film. The pressure may range from about 1 psi to about 500 psi (i.e., pounds per square inch of the flange), for example, from about 5 psi to about 400 psi, or from about 10 psi to about 300 psi, or from about 25 psi to about 250 psi, or from about 50 psi to about 200 psi, or from about 75 psi to about 200 psi, or from about 100 psi to about 200 psi, or from about 120 psi to about 180 psi, or from about 140 psi to about 180 psi, or from about 150 psi to about 170 psi. In certain embodiments, the pressure is no greater than about 500 psi, or no greater than about 400 psi, or no greater than about 300 psi, or no greater than about 200 psi, or no greater than about 150 psi, or no greater than about 100 psi, or no greater than about 75 psi, or no greater than about 50 psi. In certain embodiments, the pressure applied is based on the total surface area of seal profile. In certain embodiments, the pressure applied may vary depending on, for example, the surface area of the flange and/or the design of the container, e.g., its rigidity. As described above, heat may be applied simultaneously with pressure.

An exemplary apparatus for sealing is the GT2™ or GT2 Twin™ available from Proseal UK Ltd, an automatic, large capacity, high speed in-line tray sealing system.

Dwell time, i.e., the period of time during which heat and/or pressure is applied may advantageously be reduced owing, at least in part, to the application of the adhesive to the lidding film before sealing to the container. In certain embodiments, dwell time in the process is less than a comparative process in which adhesive is applied to the container instead of the lidding film in order to obtain the same or similar extent of seal. Also, as described above, a relatively lower temperature during dwell may be utilised in the process of invention. Dwell time may range from about 0.0 seconds to about 5 seconds, for example, from about 0.01 seconds to about 5 seconds, or from about 0.05 seconds to about 5 seconds, or from about 0.075 seconds to about 5 seconds, or from about 0.1 seconds to about 5 seconds, for example, from about 0.1 seconds to about 3 seconds, or from about 0.1 seconds to about 1 second, or from about 0.2 seconds to about 1.0 seconds, or from about 0.3 to about 1.0 second, or from about 0.2 seconds to about 0.9 seconds, or from about 0.2 seconds to about 0.8 seconds, or from about 0.2 seconds to about 0.7 seconds, or from about 0.2 seconds to about 0.6 seconds, or from about 0.2 seconds to about 0.5 seconds, or from about 0.01 seconds to about 0.5 seconds, or from about 0.01 seconds to about 0.25 seconds, or from about 0.01 seconds to about 0.1 seconds. With modern computer controlled sealing machines the dwell time can be increased by fractions of a second without slowing the line.

Any suitable lidding film may be used in the process. They are many and various.

In certain embodiments, the lidding film is a polymeric material, for example, a synthetic or natural polymer. Natural polymers include but are not limited to biopolymer, cellulosic materials (e.g., wood derived or microbial derived cellulose) and nylon-based materials.

In certain embodiments, the lidding film is or comprises a polyalkylene polymer, for example, a C2-C5 polyalkylene polymer, such as polyethylene, or polypropylene, or polybutylene. In certain embodiments, the lidding film is or comprises is polyethylene.

In certain embodiments, the lidding film comprises or is formed of polyethylene. In certain embodiments, the lidding film comprises or is formed of HDPE (high density polyethylene having a density of from about 0.93-0.97 g/cm3, and a melting point of between about 100 °C and 140 °C), LDPE (low density polyethylene having a density of from about 0.91-0.93 g/cm3 and a melting point between about 80 °C and 120 °C), or LLDPE (linear low density polyethylene having a density of from about 0.91-0.93 g/cm3 and a melting point between about 120 °C to about 160 °C).

In certain embodiments, the lidding film is a layered composite, for example, a lidding film comprising at least two layers of polymeric material. The layered composite may comprise two layers, or three layers, or four layer, or five or more layers. The layers may be formed of the same polymeric material or different polymeric materials. In certain embodiments, the lidding film comprises a layer of polyalkylene polymer, for example, polyethylene (e.g., HPDE, or LDPE, or LLDPE). In certain embodiments the lidding film comprises a layer of polyethylene and a layer of another polymeric material, for example, polyester.

In certain embodiments, the atmosphere within the sealed container is modified or controlled. Thus, in certain embodiments, the lidding film has a moisture vapour transmission rate (MVTR). In certain embodiments, the lidding film has a moisture vapour transmission rate (MVTR) of greater than 0 g/m2/day. In certain embodiments, the lidding film has a moisture vapour transmission rate equal to or greater than about 2 g/m2/day, for example equal to or greater than about 5 g/m2/day, for example equal to or greater than about 10 g/m2/day, for example equal to or greater than about 15 g/m2/day, for example equal to or greater than about 20 g/m2/day, for example equal to or greater than about 25 g/m2/day, for example equal to or greater than about 30 g/m2/day, for example equal to or greater than about 35 g/m2/day, for example equal to or greater than about 40 g/m2/day, for example equal to or greater than about 45 g/m2/day, for example equal to or greater than about 50 g/m2/day, for example equal to or greater than about 75 g/m2/day, for example equal to or greater than about 100 g/m2/day, for example equal to or greater than about 120 g/m2/day, for example equal to or greater than about 150 g/m2/day, for example equal to or greater than about 180 g/m2/day, for example equal to or greater than about 200 g/m2/day.

In certain embodiments, the lidding film has a MVTR ranging from about 5 to about 2000 g/m2/day, for example from about 5 to about 1900 g/m2/day, for example from about 5 to about 1800 g/m2/day, for example from about 5 to about 1700 g/m2/day, for example from about 5 to about 1600 g/m2/day, for example from about 5 to about 1500 g/m2/day, for example from about 5 to about 1400 g/m2/day, for example from about 5 to about 1300 g/m2/day, for example from about 5 to about 1200 g/m2/day, for example from about 5 to about 1100 g/m2/day, for example from about 5 to about 1000 g/m2/day. For example, the lidding film may have a MVTR ranging from about 10 to about 900 g/m2/day, for example from about 10 to about 800 g/m2/day, for example from about 10 to about 700 g/m2/day, for example from about 10 to about 600 g/m2/day, for example from about 10 to about 500 g/m2/day. For example, the lidding film may have a MVTR ranging from about 20 to about 2000 g/m2/day, for example from about 20 to about 1800 g/m2/day, for example from about 20 to about 1500 g/m2/day, for example from about 20 to about 1200 g/m2/day, for example from about 20 to about 1000 g/m2/day, for example from about 20 to about 800 g/m2/day, for example from about 20 to about 500 g/m2/day. For example, the lidding film may have a MVTR ranging from about 10 to about 400 cm3/m2/day, for example from about 20 to about 400 g/m2/day, for example from about 25 to about 390 g/m2/day, for example from about 40 to about 380 g/m2/day, for example from about 50 to about 370 g/m2/day, for example from about 50 to about 360 g/m2/day, for example from about 50 to about 350 g/m2/day, for example from about 100 to about 350 g/m2/day, for example from about 100 to about 340 g/m2/day, for example from about 100 to about 330 g/m2/day, for example from about 100 to about 320 g/m2/day, for example from about 100 to about 320 g/m2/day, for example from about 100 to about 310 g/m2/day, for example from about 100 to about 300 g/m2/day.

Unless otherwise stated, the MVTR may be measured according to ASTM F-1249 at 38°C and 90% relative humidity.

Another advantage of the sealed containers described herein may be that they enable a controlled amount of gas transmitted into and/or out of the sealed container. This may, for example, advantageously enable the oxygen levels within the sealed container to be maintained at a level that slows down the rate of respiration of a product packaged within the sealed container but prevents anaerobic respiration from taking place. This may, for example, reduce the rate of decay of the product and thus extend the freshness and/or shelf-life of the product. Levels of other gases such as carbon dioxide and/or nitrogen may also be maintained at levels that extend the freshness and/or shelf-life of the product.

The amount of gas transmitted by the lidding film may be controlled, for example, by altering the type and amount of polymer(s) in the film, the thickness of the film and/or the size and number of any perforations in the film. The degree of gas transmittal (e.g. oxygen transmittal) may be controlled by configuring the lidding film to transmit gas (e.g. oxygen) in a particular amount and/or at a particular rate. The inside of the container may thus be a controlled atmosphere. The exact amount of gas (e.g. oxygen) the sealed container is configured to transmit may depend, for example, on the type of produce to be packaged, the amount of produce to be packaged and the time of year.

Additionally or alternatively, therefore, the lidding film may, for example, have an oxygen transmission rate (OTR) equal to or less than about 20 cm3/m2/day. For example, the polymeric film may have an OTR equal to or less than about 19 cm3/m2/day, for example equal to or less than about 18 cm3/m2/day, for example equal to or less than about 17 cm3/m2/day, for example equal to or less than about 16 cm3/m2/day, for example equal to or less than about 15 cm3/m2/day, for example equal to or less than about 14 cm3/m2/day, for example equal to or less than about 13 cm3/m2/day, for example equal to or less than about 12 cm3/m2/day, for example equal to or less than about 11 cm3/m2/day, for example equal to or less than about 10 cm3/m2/day, for example equal to or less than about 9 cm3/m2/day, for example equal to or less than about 8 cm3/m2/day, for example equal to or less than about 7 cm3/m2/day, for example equal to or less than about 6 cm3/m2/day, for example equal to or less than about 5 cm3/m2/day. The lidding film may, for example, have an OTR from 0 cm3/m2/day to about 20 cm3/m2/day, for example from about 0.5 cm3/m2/day to about 20 cm3/m2/day, for example from about 1 cm3/m2/day to about 20 cm3/m2/day, for example from about 5 cm3/m2/day to about 10 cm3/m2/day. For example, the lidding film may have an OTR ranging from about 0 to about 15 cm3/m2/day, for example from about 0.5 to about cm3/m2/day, for example from about 1 cm3/m2/day to about 15 cm3/m2/day, for example from about 5 cm3/m2/day to about 15 cm3/m2/day. For example, the polymeric film may have an OTR ranging from about 0 to about 10 cm3/m2/day, for example from about 0.5 to about 10 cm3/m2/day, for example from about 1 to about 10 cm3/m2/day, for example from about 5 cm3/m2/day to about 10 cm3/m2/day.

Unless otherwise stated, oxygen transmission rate is measured by ASTM F-1927 at 23°C and 50% relative humidity.

In certain embodiments, the lidding film comprises perforations, which control the amount of gas (e.g. oxygen) that is able to move into or out of the sealed container. In certain embodiments, the perforations are made by a hot or cold needle. Preferably, the perforations are laser perforations. Perforations may be made prior to or after application of the adhesive. In certain embodiments, perforations are applied prior to application of the adhesive. In certain embodiments, perforations are applied after application of the adhesive.

The total surface area of the perforations may, for example, affect the total amount of gas that can be transmitted into and/or out of the sealed container. The perforations in the lidding film may, for example, be configured to transmit gas (e.g. oxygen) in an amount that will affect the shelf-life and/or freshness of a product within the sealed container but not transmit water in an amount that affects the shelf-life and/or freshness of a product within the sealed container. For example, the perforations may affect the moisture vapour transmission rate (MVTR) by an amount of about 5 cm3/m2/day or less as described above.

The perforations in the lidding film may, for example, be of any shape to allow transmittal of gas. For example, the perforations may be of any regular shape. For example, the perforations may be one or more of circles, squares, rectangles, squircles, triangles, pentagons, hexagons, heptagons, octagons. Preferably, the perforations are circular.

Where the perforations are circular, each perforation may have a diameter equal to or less than about 100 pm. For example, each perforation may have a diameter equal to or less than about 90 pm, for example equal to or less than about 80 pm, for example equal to or less than about 70 pm pm, for example equal to or less than about 60 pm, for example equal to or less than about 55 pm, for example equal to or less than about 50 pm, for example equal to or less than about 45 pm, for example equal to or less than about 40 pm, for example equal to or less than about 35 pm, for example equal to or less than about 30 pm, for example equal to or less than about 25 pm, for example equal to or less than about 20 pm, for example equal to or less than about 10 pm, for example equal to or less than about 9 pm, for example equal to or less than about 8 pm, for example equal to or less than about 7 pm, for example equal to or less than about 6 pm, for example equal to or less than about 5 pm, for example equal to or less than about 4 pm, for example equal to or less than about 3 pm, for example equal to or less than about 2 pm, for example equal to or less than about 1 pm, for example equal to or less than about 0.5 pm. Where the perforations are circular, each perforation may have a diameter of from about 0.5 pm to about 100 pm, for example, 60 pm, from about 0.5 pm to about 80 pm, for example, from about 0.5 pm to about 60 pm, for example, from about 0.5 pm to about 50 pm, for example, from about 0.5 pm to about 40 pm, for example from about 1 pm to about 30 pm, for example from about 1 pm to about 20 pm. Where the perforations are circular, each perforation may have a diameter of from about 5 pm to about 60 pm, for example from about 5 pm to about 50 pm, for example from about 5 pm to about 40 pm, for example from about 5 pm to about 30 pm, for example from about 5 pm to about 20 pm, for example from about 5 pm to about 10 pm.

The number of perforations in the lidding film may range from 0 to about 1500. For example, the number of perforations in the lidding film may range from 1 to about 1500, for example from 1 to about 1400, for example from 1 to about 1300, for example from 1 to about 1200, for example from 1 to about 1100, for example from 1 to about 1000, for example from 1 to about 900, for example from 1 to about 800, for example from 1 to about 700, for example from 1 to about 600, for example from 1 to about 500, for example from 1 to about 400, for example from 1 to about 300, for example from 1 to about 200, for example from 1 to about 100, for example from 1 to about 50, for example from 1 to about 20. For example, the number of perforations in the lidding film may range from 2 to about 1500, for example from 2 to about 1200, for example from 2 to about 1000, for example from 2 to about 800, for example from 2 to about 600, for example from 2 to about 400, for example from 2 to about 200, for example from 2 to about 100, for example from 2 to about 50, for example from 2 to about 20, for example from 2 to about 15, for example from 2 to about 10. For example, the number of perforations in the lidding film may range from 4 to about 1500, for example from 4 to about 1200, for example from 4 to about 1000, for example from 4 to about 800, for example from 4 to about 600, for example from 4 to about 400, for example from 4 to about 200, for example from 4 to about 100, for example from 4 to about 50, for example from 4 to about 20, for example from 4 to about 15, for example from 4 to about 10. For example, the number of perforations in the lidding film may range from 5 to about 100, for example from 5 to about 80, for example from 5 to about 50, for example from 5 to about 30, for example from 5 to about 20, for example from 5 to about 15, for example from 5 to about 10.

The total gas transmission of the film may, for example, be related to the total surface area of perforations in the film.

The number, size and total surface area of perforations in the polymeric film may, for example, be determined digitally using a microscopic camera.

In certain embodiments, the oxygen transmission rate (OTR) of the polymeric film may be equal to or close to 0 cm3/m2/day (e.g. up to about 5 cm3/m2/day), but the inclusion of perforations in the film (e.g. laser perforations) may increase the oxygen transmission rate. Inclusion of perforations in the film may, for example, increase the oxygen transmission rate to no more than about 20 cm3/m2/day, for example to no more than about 15 cm3/m2/day, for example to no more than about 10 cm3/m2/day, for example any of the oxygen transmission rates stated above.

In certain embodiments, the container comprises perforations, which may control, at least in part, the amount of gas (e.g. oxygen) that is able to move into or out of the sealed container. The perforations may be laser perforations. The perforations may vary in number, type and size as described above in connection with the perforation of the lidding film. In certain embodiments, both the lidding film and container have such perforations.

Advantageously, the adhesive applied, being substantially in register with the flange of the container, does not adversely affect the MVTR and/or OTR of the film.

In certain embodiments, the lidding film is a gas barrier film and/or a moisture barrier film, for example, a film having no discernible MVTR and/or no discernible OTR. Such lidding films are commonly used in the packaging of fresh or cooked fish and meat products. By “no discernible MVTR” is meant an MVTR of no greater than about 5 g/m2/day, for example, no greater than about 2 g/m2/day, or no greater than about 1 g/m2/day, or an MVTR of essentially zero or close to zero. By “no discernible OTR” is meant an OTR of no greater than about 5 cm3/m2/day, for example, no greater than about 2 cm3/m2/day, or no greater than about 1 cm3/m2/day, or an OTR of essentially zero or close to zero.

As described above, the lidding film may be a mono- or multi-layer film, e.g., two or more layers, or three or more layers, or four or more layers, or five or more layers.

Multilayer lidding films having an MVTR and OTR in accordance with certain embodiments described herein are many and various.

In certain embodiments, the lidding film comprises at least three different polymeric layers, for example at least five polymeric layers. In such embodiments, the lidding film may comprises at least one layer of polylactic acid and at least one layer of polyvinyl alcohol. The lidding film may further comprise at least one intermediate tie-layer between the at least one layer of polylactic acid and at least one layer of polyvinyl alcohol, wherein the intermediate layer comprises a blend of polylactic acid with polyvinyl alcohol and/or starch.

In certain embodiments, the lidding film comprises a first layer of a polymeric material, a second layer of a polymeric material different to the polymeric material of the first layer, and at least one intermediate tie-layer between the first and second layers, the at least one tie-layer comprising a mixture of at least the polymeric materials adjacent the tie-layer, wherein at least one of the polymeric materials within the tie layer has a melt flow index and/or melt viscosity different from the melt flow index and/or melt flow viscosity of the same polymer(s) comprising one or other layer adjacent the tie layer. In such embodiments, the lidding film may comprise at least one layer of polylactic acid, at least one layer of polyvinyl alcohol and at least one intermediate tie-layer comprising a blend of polylactic acid and polyvinyl alcohol, wherein the polyvinyl alcohol of the at least one tie-layer has a melt flow index equal to or greater than the polyvinyl alcohol of the at least one layer of polyvinyl alcohol and/or melt flow viscosity lower than the polyvinyl alcohol of the at least one layer of polyvinyl alcohol. In such embodiments, the lidding film may comprise at least one layer of polylactic acid, at least one layer of polyvinyl alcohol and at least one intermediate tie-layer comprising a blend of polylactic acid and polyvinyl alcohol, wherein the polylactic acid of the at least one tie-layer has a melt flow index equal to or greater than the polylactic acid of the at least one layer of polylactic acid and/or melt flow viscosity lower than the polylactic acid of the at least one layer of polylactic acid.

In certain embodiments, the lidding film comprises or consists of a layer of polylactic acid, followed by a tie-layer, followed by a layer of polyvinyl alcohol, followed by a tie-layer, followed by a layer of polylactic acid.

In certain embodiments, the lidding film is co-extruded.

In certain embodiments, one or more layers of a multi-layer lidding film may be selected to impart particular properties other than for atmospheric control, such as strength, resilience, shrinking and UV stability.

The lidding film is preferably transparent, although it may be opaque or translucent.

In certain embodiments, the lidding film has a thickness of from about 5 pm to about 1 mm, for example, from about 5 pm to about 500 pm, or from about 10 pm to about 250 pm, or form about 10 pm to about 150 pm, or from about 10 pm to about 100 pm, or from about 20 pm to about 100 pm, or from about 30 pm to about 100 pm, or from about 30 pm to about 80 pm. In certain embodiments, the lidding film has a thickness of at least about 20 pm, or at least about 30 pm, or at least about 50 pm, or at least about 100 pm, or at least about 150 pm, or at least about 200 pm, or at least about 250 pm.

Labelling may be fixed to the lidding film, by physical means or by printing directly on to the film. Any suitable printing apparatus may be used to impart a print design and the like on the opposite surface of the lidding film to which the adhesive is applied.

In certain embodiments, the seal formed between lidding film and the container is a peelabe seal, or an easy open seal or a lock seal. Suitable combinations of adhesive and lidding film may be selected to provide the desired seal. A peelable seal may be characterized as adhesive failure.

In certain embodiments, the other surface (i.e., the surface opposite the surface to which adhesive is applied) of the lidding film is treated with a release coating or lacquer to reduce or eliminate sticking of the lidding film to the apparatus of the manufacturing, for example, the heat sealing head or heads used to impart heat to the lidding film and seal it to the container. Advantageously, however, the need for a release coating or lacquer may be reduced or eliminated owing to the favourable lower temperatures that may be employed to seal the lidding film to the container (owing, as discussed above, at least in part to the application of the adhesive to the lidding film and not the container).

In certain embodiments, the lidding film is suitable for packaging fresh produced, for example, fruit, vegetables, fungi, fish, meat, wheat-based produces such as bread and pasta, cakes and the like, confectionery, or biscuits, dairy products, such as cheese, fromage fraise, cream, yoghurt and the like, yeast-based products, or non-edible products requiring or benefitting from controlled atmospheric packaging in order to maintain or extend shelf-life, for example, fresh flowers.

In certain embodiments, the lidding film is suitable for packaging cooked, partially cooked or otherwise processed foodstuffs, for example, ready meals.

In certain embodiments, the lidding film is suitable for packaging medicines, for example, a pharmaceutical product or items which may be found in a first aid kit, or personal care products.

By “adhesive” is meant any material or composition that enables adhesion of the lidding film to the container, for example, to the flange of the container (e.g., creates a bond between the lidding film and the container). Any suitable adhesive may be used provided it can be applied to a surface of the lidding film at one or more selected areas. In certain embodiments, the adhesive is capable of being applied by a printing technique, for example, by a flexographic printing technique, or a gravure printing technique, or a digital printing technique. In certain embodiments, the adhesive is applied using gravure printing. In certain embodiments, a print design and registration marks are applied using flexographic printing followed by an inline gravure printer for application of the adhesive. In certain embodiments, all of the print design, registration marks and adhesive are applied by flexographic printing. In certain embodiments, all of the print design, registration marks and adhesive are applied by gravure printing.

Suitable adhesives include polyurethanes, epoxies, polyesters, acrylics, anhydride modified polyolefin and blends thereof.

In certain embodiments, the adhesive is a hot meld adhesive.

In certain embodiments, the adhesive may be a PE or PE co-polymer based material.

In certain embodiments, the adhesive is tridecylpoly(ethyleneoxy)ethanol, available as R8847-Lidding Adhesive 2 (TM) from Inktech Ltd. In certain embodiments, the adhesive is R8843 (TM), which is a development adhesive designed for a peelable lidding adhesive available from Inktech Ltd. This adhesive has the appearance of a white liquid, a viscosity of from about 80- 120 cps (Brookfiled 1/50 at 20 °C), a solids content of about 49 %, and a pH of from about 6-7.

In certain embodiments, the adhesive is suitable for use in packaging of foodstuffs, i.e., is a food-grade adhesive.

The thickness of the adhesive strip or layer can vary. For example, the adhesive strip or layer may have a thickness of from about 0.1 pm to about 500 pm, for example, from about 0.1 to about 400 pm, of form about 0.1 to about 300 pm , or from about 0.1 pm to about 250 pm , or from about 0.2 pm to about 200 pm, or from about 0.3 pm to about 150 pm, or from about 0.4 pm to about 100 pm, or from about 0.5 pm to about 75 pm, or from about 0.5 pm to about 50 pm, or from about 0.5 pm to about 25 pm, or from about 0.5 pm to about 20 pm, or from about 0.5 pm to about 15 urn, or from about 0.5 pm to about 10 pm, or from about 0.5 pm to about 9 pm, or from about 0.5 pm to about 8 pm, or from about 0.5 pm to about 7 pm, or from about 0.5 pm to about 6 pm, or from about 0.5 pm to about 5 pm.

The container may be formed of any material or substrate suitable for use in sealed containers, particularly in the packaging of foodstuffs such as fresh produce and the like, or any of the other items for packaging described herein. The container may be a tray or punnet or cup. The container may be clear, opaque, translucent or otherwise coloured.

In certain embodiments, the container is formed of a plastic material, for example, PET or PLA, and the like, or R-PET, A-PET, C-PET, polypropylene, PVC, styrene, and the like, and a combination thereof. The plastic material, for example, PET and PLA may be recycled PET and/or PLA.

In certain embodiments, the container is foil based, for example, a smooth walled foil.

In certain embodiments, the container is formed from or of, or comprises, a pulpable, fibrous material. Such a container may comprise an amount of polymer which is compatible with the lidding film and/or adhesive. The amount of polymer may be in the range of from about 1 wt. % to about 80 wt. %, based on the total weight of the container. The polymer may be selected based on its compatibility with the lidding film and/or adhesive, for example, to create, maintain or improve the bond between the lidding film and the container.

The fibrous material may be derived from derived from wood, grasses (e.g., sugarcane, bamboo) or rags (e.g., textile waste, cotton, hemp or flax), preferably from wood. In certain embodiments, the fibrous material is a cellulosic material. In certain embodiments, the fibrous material is derived from palm fibre. In certain embodiments, the fibrous material is derived from recycled paper, for example, recycled paper board.

Typically, the container comprises at least about 80 wt. % fibrous material, based on the total weight of the container, for example, at least about 85 wt. % fibrous material, or at least about 90 % fibrous material, or at least about 91 % fibrous material, or at least about 92 wt. % fibrous material, or at least about 93 wt. % fibrous material, or at least about 94 wt. % fibrous material, or at least about 95 wt. % fibrous material, or at least about 96 wt. % fibrous material, or at least about 97 wt. fibrous material, or at least about 98 wt. % fibrous material. The container may comprise from about 90-99.5 wt. % fibrous material, for example, from about 90-99 wt. % fibrous material, or from about 90-98 wt. %, or 90-97 wt. %, or 90-96 wt. %, or 90-95 wt. %, or 90-94 wt. %, or 90-93 wt. % fibrous material.

In certain embodiments, the container comprises an additive for varying the moisture and/or water resistance and/or gas transmission properties of the container. The additive for varying the moisture and/or water resistance of the container may be present in an amount (i) sufficient to prevent the container from absorbing moisture and/or water to the extent that the integrity of the container is compromised in use, and (ii) such that the container is able to absorb an amount of moisture and/or water to the extent that the flexibility of the container is increased. The additive is not formed as a coating on fibrous material, but instead is dispersed within and throughout the fibrous material. This may achieved during the manufacturing process in which the additive is mixed with pulp prior to moulding. Generally, the amount of additive for varying the moisture and/or water resistance and/or the gas transmission properties of the container may range from about 0.1 wt. % to about 80 wt. %, based on the total weight of the tray, for example, from about 0.1 to about 70 wt. %, or from about 0.1 to about 60 wt. %, or from about 0.1 to about 50 wt. %, or from about 0.1 to about 40 wt. %, or from about 0.1 to about 30 wt. %, or from about 0.1 to about 25 wt. %, or from about 0.1 to about 20 wt. %, or from about 0.1 to about 15 wt. %, or from about 0.1 to about 10 wt. %, or from about 0.5 to about 8.0 wt. %, or from about 0.5 to about 6.0 wt. %, for from about 0.5 to about 5.0 wt. %, or from about 1.0 to about 4.5 wt. %, or from about 1.0 to about 4.0 wt. %, or from about 1.0 wt. % to about 3.5 wt. %, or from about 1.0 to about 3.0 wt. %, or from about 1.0 to about 2.5 wt. %, or from about 1.0 to about 2.0 wt. %, or from about 1.5 wt. % to about 4.5 wt. %, or from about 2.0 wt. % to about 4.0 wt. %, or from about 2.0 to about 3.5 wt. %, or from about 2.5 wt. % to about 3.5 wt. %, or from about 2.0 to about 3.0 wt. %. In certain embodiments, the additive or additives for varying the moisture and/or water resistance of the container may be different than the additive for varying the gas transmission properties of the container.

Requirements (i) and (ii) mean that the container includes an amount of the additive such that the container is able to absorb a certain amount of moisture and/or vapour to increase the flexibility of the container (or conversely decrease the rigidity of the container), but prevented from absorbing too much moisture and/or water such that the container fails in use (e.g., it becomes too bendy or even disintegrates).

In certain embodiments, the level of additive should be selected such that the container does not fail following packaging, transportation, storage and display over a 5.5 day period, or a 6 day period, or a 6.5 day period, or 7 day period. Generally, the longer the period between packaging and sale, the greater the amount of additive that will be required to prevent the container from absorbing too moisture and/or water. A skilled person will be able to determine the appropriate amount of additive by packaging a container, for example, with fresh produce, and then storing the packaged container at ambient conditions over a 5 day period (or a 5.5 day period, etc) and assessing the integrity of the container and the end of the period.

In certain embodiments, the additive for varying the moisture and/or water resistance of the container is wax, for example, natural wax or synthetic wax. In certain embodiments, the wax is a natural wax selected from group consisting of paraffin wax, beeswax, rice bran wax, carnuba wax, candelilla wax, ouricury wax, sugarcane wax, retamo wax, lanolin and jojoba oil, and mixtures thereof. Advantageously, the wax is a paraffin wax. A paraffin wax is understood to refer to mixtures of mainly straight-chain, saturated hydrocarbons produced from petroleum, lignite or shale tar oil. An exemplary paraffin wax is BIM SE 9244, available from BIM (RTM) Kemi Sweden AB.

Like all of the components of the container of the invention, in certain embodiments, the additive for varying the moisture and/or water resistance of the tray should comply with any regulatory requirements dealing with food packaging. These may vary depending on the territory in which the container is to be used and sold. For example, the additive for varying the moisture and/or water resistance of the tray preferably complies with FDA: 21 CFR 176.170 (2012); FDA: 21 CFR 176.180 (2012); and BfR XXXVI (2012) “Paper and board for food contact”.

In certain embodiments, the container comprises at least about 80 wt. % fibrous material and from about 0.1 to about 10 wt. % of the additive for varying the moisture and/or water resistance of the container, based on the total weight of the container, for example, at least about 90 wt. % fibrous material and from about 0.5 to about 5 wt.% of the additive for varying the moisture and/or water resistance of the container, or at least about 95 wt. % fibrous material and from 0.5 to about 5 wt. % of the additive for varying the moisture and/or water resistance of the container.

In certain embodiments, the container is coloured. By coloured is meant that the colour of the container is different to that of the natural colour of the fibrous material from which the container is formed. Thus, in certain embodiments, the container comprises a colourant, for example, a dye or pigment, preferably a dye. The colourant, e.g., dye, may be added during preparation of the pulp from which the tray is to be moulded, as discussed below. The colourant may be selected so to impart and desired colour to the container. In certain embodiments, the colourant is a black colourant, blue colourant or a mixture of black and blue colourant, for example, a black dye, a blue dye or a mixture of black and blue dye. An exemplary black dye is Cartasol Black M-G liquid, available from Clariant (RTM) Products, Switzerland. An exemplary blue dye is Cartasol Blue K5R liquid, available from Clariant (RTM) Products, Switzerland.

The colourant should comply with any regulatory requirements pertaining to the use of colourants in food packaging. These may vary depending on the territory in which the container is to be used and sold. For example, the colourant preferably complies with Regulation (EC) No 1935/2004 of the European Parliament and of the Council of 27 October 2004 on materials and articles intended to come into contact with food. The container may comprise up to about 5 % by weight colourant, based on the total weight of the container, for example, from about 0.1 to about 4.5 wt. % colourant, or from about 0.5 to about 4.0 wt. % colourant, or up to about 3.5 wt. % colourant, or up to about 3.0 wt. % colourant, or up to about 2.5 wt. % colourant, or up to about 2.0 wt. % colourant, or up to about 2.0 wt. % colourant, or up to about 1.5 wt. % colourant, or up to about 1.0 wt. % colourant.

In certain embodiments, the container further comprises a biocide. This may be added to protect fresh produce contained within the container, for example, to prevent or inhibit microbial spoilage, e.g., rotting, of fresh produce, and also to protect the manufacturing equipment for making the container. The biocide may be a synthetic or natural biocide, preferably a synthetic biocide. An exemplary natural biocide is chitosan. The biocide may be an antimicrobial agent, for example, a germicide, antibacterial agent, antifungal agent, antiprotozoal agent, or a antiparasite agent. Antimicrobial agents also include weak acids, organic acids (.e.g., lactic acid, citric acid, acetic acid, and their salts), bacteriocins, enzymes, and fungicides, among others.

In certain embodiments, the biocide is based on a quaternary ammonium compound. Typically, these compounds comprise one or more polar quaternary amine head groups and a hydrophilic tail (e.g., a long alkyl chain). Although there can be many variations in the minutiae of their structures, the length of the alkyl chain is generally between about 8 and 20 carbon atoms, for example, between about 8 and 16 carbon atoms. An exemplary biocide of this type is Solcide SL 106 (Revision Nr: 0 of 15-08-2011), available from Solstar (RTM). It is based on a twin chain quaternary ammonium compound. This biocide may also comprise glutral.

In certain embodiments, the biocide may be based on a glutaraldehyde compound and/or a isothiozolone compound, for example, 5-chloro-2-methyl-2H-isothiazol-3-one and/or 2-methyl-2H-isothiazol-3-one. An exemplary biocide is Solcide P 103 (Revision Nr: 0 of 12-05-2010), available from Solstar (RTM). Another exemplary biocide is Solcide P 112 (Revision Nr: 0 of 22-03-2011), available from Solstar (RTM).

In certain embodiments, the biocide may be based on an amide compound, for example, a propionamide, such as, for example, 2,2-di-bromo-3-nitrilo-propionamide. An exemplary biocide is Solcide P 107 (Revision Nr: 0 of 10-04-2010), available from Solstar (RTM).

The biocide should comply with any regulatory requirements pertaining to the use of biocides in food packaging. These may vary depending on the territory in which the tray is to be used and sold.

In certain embodiments, the container comprises up to about 3 wt. % biocide, for example, up to about 2 wt. % biocide, or up to about 1 wt. % biocide, or up to about 0.9 wt. % biocide, or up to about 0.8 wt. % biocide, or up to about 0.7 wt. % biocide, or up to about 0.6 wt. % biocide, or up to about 0.5 wt. % biocide, or up to about 0.4 wt. % biocide, or up to about 0.3 wt. % biocide, or up to about 0.2 wt. % biocide. Typically, when present, the container will comprise at least about 0.05 wt. % biocide, for example, at least about 0.1 wt. % biocide.

The biocide may be added during preparation of the pulp from which the container is to be moulded.

In certain embodiments, the container consists of fibrous substrate, the additive for varying the moisture and/or water resistance of the container, e.g., wax, and the polymeric film. In such embodiments, the fibrous material may constitute at least about 90 wt.%, or at least about 95 wt. % of the container, with the balance additive for varying the moisture and/or water resistance of the container, e.g., wax, and the polymeric film. Relative to the body of the container, the lidding film will be understood to have negligible weight.

In certain embodiments, the container comprises: (i) from about 90-98 wt. % fibrous material; (ii) from 0.1 to about 5 wt. % additive, e.g., wax; (iii) up to about 4.0 wt. % colourant, or from about 0 to 4 wt. % colorant; and (iv) up to about 2.0 wt. % biocide, or from about 0 to 2.0 wt. biocide, for example, up to about 1.0 wt. % biocide.

Advantageously, the container is moulded, for example, a one-piece moulded container which may be biodegradable and/or recyclable.

In certain embodiments, the container is a rigid or semi-rigid container.

In certain embodiments, the process is operated as a continuous process in which containers (having a product placed therein) are supplied continuously to a production line for continuous application of the lidding film (having the adhesive applied thereto) to the container. Alternatively, the process may be operated as a batch process. Alternatively, the process may be operated as a combination of a continuous process and batch process steps. For example, the containers may be supplied by a batch process and application of the lidding film may operate as a continuous process. The process, for example, continuous process, may operate or be operated at any suitable line speed.

In certain embodiments, the container does not comprise a flange and the seal is formed between an uppermost part of the exterior of the side wall and the polymeric film (e.g., a portion of the polymer film is “folded” over the outer periphery of the rim of the container). In certain embodiments, the side wall may be of sufficient thickness (e.g., at least about 2 mm, or at least about 3 mm, or at least about 4 mm, or up to about 5 mm) such that a seal may be formed between the extent of the thickness of the side wall and the polymeric film. In such embodiments, the side wall may not be of uniform thickness, e.g., it may be thinner at the base than at its uppermost part.

In certain embodiments, the seal formed between the lidding film and the side wall and/or flange is the only point of contact between the lidding film and the container. In certain embodiments, following application, less than about 50 % of the surface area of the lidding film may be in contact with the container. In certain embodiments, less than about 25 % of the surface area of the lidding film is in contact with the container, for example, less than about 20 %, or less than about 15 %, or less than about 10 %, or less than about 5 %, or less than about 2.5 % or, less than about 1 % of the surface area of the lidding film is in contact with the container. In certain embodiments, at least about 0.1 % of the surface are of the lidding film is contact with the container, for example, at least about 0.5 % of the surface area of the lidding film is in contact with the container.

In certain embodiment, the process of the first aspect of the present invention further comprises process for making the lidding film for sealing the container, the process comprising applying adhesive to a selected area of one of its surfaces, wherein the selected area corresponds to a sealing area between the lidding film and the container to which it is to be applied. Advantageously, the adhesive may be applied to the lidding film in register, for example, in register with the shape of a flange of the container. The adhesive may be applied by a printing technique, for example, by gravure. Other embodiments of the process are described above in accordance with the process of the first aspect of the present invention.

In certain embodiments, the process further comprise applying a design and/or registration mark(s) to a surface of the lidding film prior to applying adhesive to the other surface of the lidding film. The design may be in the form of a label, or it may be printed onto the surface of the film opposite that to which adhesive is subsequently applied. The design may be pictorial, or comprise branding and/or instructions and/or pricing information and/or information about the product to be sealed in the container.

In certain embodiments, the process further comprises perforating the film before applying the adhesive. Perforating may be carried out after application of a design and/or registration mark(s). Further embodiments of the perforating process are described above.

The process will typically further comprising cutting, after sealing, to produce individual sealed containers, which may then be sent for packaging and distribution. Any suitable cutter or cutter arrangement may be utilised.

Also provided is a sealed container obtainable by the process according to first aspect of the present invention and any or all embodiments thereof described herein. The sealed container may be further characterised in terms of the level of adhesive that comes away with the lidding film upon peeling off the lidding film. In certain embodiments, at least 10 % by weight of the adhesive is retained on the film following peeling of the lidding film, for example, at least about 20 % by weight, or at least about 30 % by weight, or at least about 40 %, by weight. Advantageously, a majority of the adhesive (i.e., greater than about 50 % by weight of adhesive applied) is retained on lidding film following peeling off the lidding film, for example, at least about 55 % by weight, or at least about 60 % by weight, or at least about 65 % by weight, or at least about 70 % by weight, or at least about 75 % by weight, or at least about 80 % by weight, or at least about 85 % by weight, or at least about 95 % by weight, or at least about 99 % by weight of the adhesive applied to the lidding film is retained on the lidding film following peeling off the lidding film. The sealed container may be characterised by other properties, for example, strength or resilience of the film after application. For example, in certain embodiments, the lidding film following application has a strength and/or resilience which is greater than the strength and/or resilience of comparable sealed container made by a process which is adhesive is not applied to the lidding film.

Standard tests include seal strength/integrity (ASTM F88, F1886, F1929, F2228), hot tack (ASTM F1921), drop testing (ASTM D5276), burst strength (ASTM F1140, F2096, F2338) and compression (ASTM D642) or stacking strength (ASTM D4577). Each test may or may not be necessary for a particular packaging application.

Quality Assurance testing for food includes test such as permeability of the film (ASTM F1307, F1927, F372-73, D1434, F1769), migration (ASTM D4754), resistance to flex cracking (ASTM F392), or microwave testing (ASTM F1308, F1500, F1519). The use and type of a product determines the necessity of a particular test.

In certain embodiments, the sealed container is suitable and/or intended for packaging individual pieces of fresh produce, particularly fresh produce. Fresh produce includes fruit, vegetables, meat, fish and fungi, e.g., mushrooms.

In certain embodiments, the container is suitable for packaging a wide range of fruits, such as, for example, apples and pears, grapes, citrus fruit, berries, melons, stone fruits, tomatoes, and exotic fruits.

Stone fruits include, apricots, avocados, cherries, dates, greengages, nectarines, peaches and plums, particular the soft skinned stoned fruits which are particularly sensitive to bruising and blemishing during packaging, transport and storage.

Citrus fruits include clementines, grapefruit, kumquats, lemons, limequat, minneolas, oranges, pomelo and satsumas.

Berries include strawberries, blueberries, blackberries, cranberries, gooseberries, raspberries, redcurrants, blackcurrants and white currants.

Melons include varieties such as cantelope, charantais, galia, honeydew, rock and water.

Exotic fruits include custard apple, figs, grenadillo, guava, kiwano (horned melon), kiwi, longuns, lychees, mangoes, mangosteen, passion fruit, paw paw, persimmon, physalis, pineapples (baby), pitahaya red, pitahaya yellow, pomegranates, prickly pear, quinces, rambutans, rhubarb, sharon fruit, star fruit, tamerillo and zespri golden.

Mushrooms include varieties such as button, cepes, chanterelles, chestnut brown, cup, enoki, flat, girolle, gold trumpet, mixed wild, morilles, mousseron, oyster, pied de bleu, pied de mouton, pink oyster, Portobello, shitaki, trumpe de la mor and yellow oyster.

In certain embodiments, the container is suitable for packaging a wide range of vegetables, such as root vegetables, potatoes, onions and shallots, capsicums, broccolis, chillies, beans, mange tout and peas, exotic vegetables and a selection of other general vegetables.

Root vegetables include beetroot, carrots, celeriac, parsnips, swedes and turnips. Onions and shallots include varieties such as button, cipolino, English, grelot, red, Spanish, strings, white skinned and banana.

Broccolis include sprouting broccoli, button sprouts, red, white and savoy cabbage, cauliflower, curly kale, purple broccoli and brussels sprouts.

Other general vegetables include aubergines, chicory, fennel, leeks, marrows, round courgettes and butternut squash.

In certain embodiments, the container is suitable for packaging a wide range of meats, such as poultry, beef, lamb and pork, or a wide range of fish, for example, those indigenous to UK waters, such as cod, haddock, pollock, mackerel, herring, salmon, sardine, hake, monk fish, halibut, turbot, or non-native fish, such as those indigenous to continental Europe and/or further afield internationally, or shell fish, e.g., prawns, mussels, shrimp, cockles, etc, crab or lobster, and the like.

In certain embodiments, the sealed container is suitable for packaging a wide variety of cooked or partially cooked foodstuffs, for example, cooked meats, and ready-meals.

In certain embodiments, the sealed container is suitable for packaging a wide-variety of dairy products, for example, cheese, fromage fraise, yoghurt, cream and the like.

In certain embodiments, the sealed container is suitable for packaging a wide variety of non-foodstuffs, i.e., non-edible products which will benefit from packaging in controlled atmospheric conditions. Examples include flora and fauna, such as, for example, fresh flowers.

Also provided is a manufacturing system configured to carry out a process for sealing a container according to the first aspect of the present invention. The system comprises a supply of containers having an opening, a supply of lidding film, a supply of adhesive and apparatus for applying adhesive to the lidding film in a selected area(s) and an apparatus for sealing the lidding film to the container. The apparatus for sealing the lidding film to the container may form the seal by the application of heat and/or pressure to the lidding film and/or container.

In certain embodiments, the manufacturing system further comprises: (i) a first print apparatus for applying a print design and/or one or more registration marks to a surface of the lidding film, and/or (ii) a second print apparatus for applying adhesive to the lidding film in registration with the flange of the container to which the lidding film is to be sealed, and/or (iii) an apparatus for perforating the lidding film, for example, a laser perforator, and/or (iv) an apparatus for placing an article of commerce, for example, foodstuff, in the container in the opening prior to sealing, and/or (v) a cutting means (e.g., a cutter) for cutting the lidding film during or following sealing.

The manufacturing system may be configured for continuous processing as herein described and further comprises conveying means, e.g., conveyor belts for the lidding film and containers. Alternatively, the manufacturing system may be configured for batch processing, or a combination of continuous and batch processing, as herein described

In certain embodiments, a plurality of containers are processed substantially simultaneously and the manufacturing system is configured accordingly. In certain embodiments, between 2 and 10 trays may be manufactured substantially simultaneously, for example, at least 4 trays, or at least 6 trays, or at least 8 trays. For example, eight trays, in four side-by-side pairs, may be manufactured substantially simultaneously. Other configurations are possible and will be apparent to a person of skill in the art.

The invention will be further described with reference to the drawings and figures. Figures 2-6 depict, respectively, various process steps of the overall process form making a sealed container according to certain embodiments of the present invention. For clarity and to enhance understanding, the overall process is described in terms of various process steps, i.e., process 1, process 2, process 3, process 4, etc. It will be understood, however, that these process steps may be part of an overall continuous process and that which is produced at the end of any one process is fed to the next stage of the process, and so on, resulting in the production of individual sealed containers, which may be then stored or transported. The speed of conveyance of the sheet of lidding film may be any suitable speed for processing of the film through the various process, including the sealing step. The overall process may be automated and computer controlled.

Fig. 2 is a simplified illustration (side elevation) of initial process steps (application of print design, eye mark(s) and adhesive in register), hereinafter referred to as Process 1 and Process 2. Process 1 according to one illustrated embodiment comprises the application of a print design and registration marks to the upper surface of lidding sheet (200), which is conveyed between a pair of rollers having a core (206) about which the lidding sheet (200) is wound. The print design may be applied using any suitable printing apparatus (210). In certain embodiments, the print design and/or registration marks is applied any suitable printing technique, for example, a flexographic printing technique, gravure or digital printing. Inket or laser printing may also be used. Advantageously, the print design and registration marks are applied by flexographic printing. In certain embodiments, the lidding sheet is sufficiently wide (e.g., about 600 mm) to accommodate two or more lidding films side-by-side (for example, as shown in Fig. 7 discussed below). The printed lidding sheet is than conveyed to an adhesive application station according to Process 2, in which a strip or layer of adhesive is applied to the underside of the lidding film in register using another printing apparatus (212). The printing apparatus (210) has means for detecting the registration marks, for example, an optical sensor, which guides the application of adhesive in register and in the appropriate shape and size corresponding to the shape of the flange of the container which is to be sealed. In certain embodiments, the printing apparatus (212) is a flexographic printer or a gravure printer or a digital printer, advantageously a gravure printer. In certain embodiments, Process 2 and Process 3 are “in-line” meaning that the sheet of lidding film is conveyed directly from Process 1 to Process 2. In such embodiments, a flexographic printing apparatus with an inline gravure system may be used to apply the design/registration marks and adhesive, respectively. The lidding sheet/film with adhesive applied is then conveyed or fed to Process 3. Advantageously, in certain embodiments, Process 2 and Process 3 are “in-line” meaning that the sheet of lidding film is conveyed directly from Process 2 to Process 3.

Fig. 3a is a simplified illustration (side elevation) of Process 3. In Process 4 the lidding sheet (200) from Process 3 is subjected to laser perforation using a laser perforation apparatus (214). Suitable apparatus (214) are described above herein. The laser perforation pattern may be applied in register. The lidding sheet (200) may again be wound on a roller having a core (206) prior to Process 3. In certain embodiments, Process 3 and Process 4 are “in-line” meaning that lidding film is conveyed directly from Process 3 to Process 4. As shown in Fig. 3a (side elevation) and Fig. 3b (shown from a bird’s eye view), following perforation, the lidding sheet (200) is slit into two separate rolls (200a and 200b) and wound on a pair of rollers (206a) prior to Process 5.

Fig. 4 is a schematic depiction (side elevation) of eye-mark registration (220) between the lidding sheet/film 200a or 200b and containers (216) according to Process 5 ready for sealing in accordance with Process 6. Containers (216) are supplied and fed to the process via conveyor (218). Pressure-application apparatus (222) is located proximate the containers (216). In certain embodiments, Process 4 and Process 5 are “in-line” meaning that the sheet of lidding film is conveyed directly from Process 4 to Process 5.

Fig. 5 is a schematic depiction (side elevation) of the sealing step according to Process 6. In this illustrated embodiment, the containers (216) are brought up to the lower surface of lidding sheet (200a or 200b) having the adhesive applied in register. The act of bringing containers (216) up to and in contact with the lower surface of the lidding sheet/film (200a/200b) results in the application of pressure from below the lidding sheet/film (200a/200b). Apparatus (222) for raising the containers (216) to the lower surface of the lidding sheet/film (200a/200b) may comprise a series of arms and grabbers which grab the outside of the containers (216) and raise them up. To seal the lidding film (200a or 200b) to the containers (216) heat is applied from above for a suitable dwell time via a suitable heating apparatus (224). A seal (228) is formed between the lidding film and the flange of the container via the adhesive. The apparatus (224) may comprise one or more heat sealing heads or shoes (not shown) having a shape which matches the flange of the containers (216). A cutter (not shown) quickly cuts the sheet of lidding film producing individual sealed containers (216a). The individual sealed containers (216a) are then conveyed via conveyor (218) to a finishing zone or stacking zone (not shown) for storage, distribution or transportation. The waste lidding sheet (300) is conveyed away from the heat and dwell apparatus (224) and wound on another roller (206). The waste lidding sheet may be trashed or sent for recycle. The heat and dwell apparatus (224) and the eye-mark registration apparatus (220) may be part of the same apparatus and positioned at essentially the same position in the overall continuous process.

Fig. 6 is a schematic depiction (side elevation) of post-sealing Process 6 according to one illustrated embodiment. The pressure-applying apparatus (222) brings the sealed containers (216a) back down onto conveyor (218), and the individually sealed containers (216a) are then conveyed via conveyor (218) to a finishing zone or stacking zone (not shown) for storage, distribution or transportation. As described above, the waste lidding sheet (300) is conveyed away from the heat and dwell apparatus (224) and wound on another roller (206). A subsequent series of containers (not shown) are then fed in below the eye mark registration apparatus (220) and the sealing process repeats.

Fig. 7a is a plan view of a continuous sheet of lidding film from which the lidding films (204) are formed during the sealing process according to one illustrated embodiment. The dimensions indicated are exemplary and not limiting. The expanded view provided in Fig. 7b of lidding film (204) shows the inner (104) and outer (102) extremities of a layer of adhesive applied to the underside of the lidding film (204). This substantially corresponds to and matches (i.e., is in register) the shape and size of the flange of the container to which the lidding film (204) will be sealed. Cut line (100) indicates where the lidding film (204) would be cut from lidding sheet (200) following sealing to the container. Innermost line (106) indicates a degree of tolerance of the width of the adhesive, i.e., in this illustrated embodiments, the width of the layer of adhesive could be wider than the flange to an extent indicated by line 106. However, as described generally above, the adhesive may cover a greater area of the surface of the lidding film than indicated in Figure 7. Lidding sheet (200) shows how a plurality of lidding films (204) may be positioned along the length of the sheet (200), with registration marks (202) applied along the length of the sheet (200). The large arrow indicates the direction of travel of the lidding sheet/film (200). Lidding sheet (200) may have a width suitable to accommodate the size of the lidding films (204) to be formed therefrom. In certain embodiments, there may be only a single line of lidding films (204) instead of the side-by-side arrangement depicted in Fig. 7a. In certain embodiments, there could be three or more lidding films (204) in a side-by-side arrangement. The group of eight lidding films (204) shown in Figure 7 will be processed essentially simultaneously in the continuous lidding process. Lidding sheet (200) is initially disposed, e g., wound, on a core (206), and then drawn from the core at the desired speed.

Claims

1. A process for making a sealed container, wherein the process comprises: (a) proving a lidding film having adhesive applied to a selected area of one of its surfaces; (b) providing a container comprising a base and continuous side wall extending generally upwards from the base; and (c) applying the lidding film to the container such that the lidding film is sealed to the container.

2. A process according to claim 1, wherein the adhesive is applied to the lidding film in register and corresponding to a sealing area between the lidding film and the container.

3. A process according to any preceding claim, wherein the container has a flange formed along the upper edge of the continuous side wall and adhesive is applied to the lidding film such that the lidding film is sealed to the container via the flange only.

4. A process according to claim 3, wherein the adhesive is applied as a continuous layer or strip corresponding to, for example, in register with, the flange.

5. A process according to any preceding claim, wherein the adhesive is applied by a printing technique, for example, by flexographic printing or by gravure or by digital printing, preferably by gravure printing.

6. A process according to any preceding claim, wherein the lidding film has one or more registration marks to guide the application of adhesive to the selected area.

7. A process according to any preceding claim, wherein heat and/or pressure is applied to the lidding film and/or the container to seal the lidding film to the container.

8. A process according to claim 7, wherein: (i) heat is applied simultaneously with pressure; or (ii) heat only is applied; or (iii) pressure only is applied.

9. A process according to claim 7 or 8, wherein heat is applied to the upper surface of the film.

10. A process according to any one of claims 7-9, wherein heat is applied to the lidding film and/or the container at a temperature of no greater than about 500 °C, for example, no greater than about 175 °C.

11. A process according to any preceding claim, wherein heat is not applied to the lidding and/or container to seal the lidding film to the container.

12. A process according to any one of claims 7-10, wherein heat is applied to the lidding film at a temperature below that which would cause degradation of the film and/or sticking of the lidding film to a sealing head used during application of the lidding film to the container.

13. A process according to any preceding claim, wherein the atmosphere within the sealed container is modified or controlled.

14. A process according to any preceding claim, wherein the lidding film has a MVTR and/or an OTR.

15. A process according to claim 14, wherein the adhesive applied does affect the MVTR and/or OTR of the film.

16. A process according to any one of claims 1-12, wherein the lidding film is a gas barrier film and/or a moisture barrier film, for example, a film having no discernible MVTR and/or no discernible oxygen transmission rate.

17. A process according to any preceding claim, wherein the lidding film is a mono- or multi-layer film.

18. A process according to any preceding claim, wherein the lidding film has a thickness for from about 5 pm to about 150 pm.

19. A process according to any preceding claim, wherein the film is perforated, for example, laser perforated, and the adhesive applied does not affect the function of the perforations.

20. A process according to any preceding claim, wherein the seal formed between lidding film and the container is peelabe seal, or an easy open seal or a lock seal.

21. A process according to any preceding claim, wherein the container is formed of plastic, for example, PET.

22. A process according to any one of claim 1-19, wherein the container is formed from or of, or comprises, a pulpable, fibrous substrate, optionally wherein the container comprises polymer which is compatible with the lidding film and/or adhesive.

23. A process according to any preceding claim, wherein the process is a continuous process.

24. A process according to any preceding claim, wherein the other surface of the lidding film is treated with a release coating or lacquer.

25. A process according to any preceding claim, wherein the lidding film is suitable for packaging fresh produce, for example, fruit, vegetables, fungi, fish, dairy products or meat, or non-edible fresh produce.

26. A process according to any one of claims 1-24, wherein the lidding film is suitable for packaging cooked, partially cooked or otherwise processed foodstuffs, for example, ready meals, or cheese.

27. A process according to any one of claims 1-24, wherein the lidding film is suitable for packaging medicines, for example, a pharmaceutical product.

28. A process according to any one of claims 1-27, wherein the adhesive is or comprises tridecylpoly(ethyleneoxy)ethanol.

29. A lidding film for sealing a container, the lidding film having adhesive applied to a selected area of one of its surfaces, wherein the selected area corresponds to a sealing area between the lidding film and the container to which it is to be applied.

30. A lidding film according to claim 29, wherein the lidding film and adhesive are as defined in any one of claims 1-28.

31. A process for making a lidding film for sealing a container, the process comprising applying adhesive to a selected area of one of its surfaces, wherein the selected area corresponds to a sealing area between the lidding film and the container to which it is to be applied., optionally wherein the adhesive is applied to the lidding film in register, for example, in register with the shape of a flange of the container, optionally wherein the adhesive is applied by a printing technique such as, for example, by flexographic printing or by gravure or by digital printing.

32. A process according to any one of claims 1-28, further comprising the process according to claim 31.

33. A process according to 31 or 32, further comprising applying a design and/or registration mark(s) to a surface of the lidding film prior to applying adhesive to the other surface of the lidding film, optionally wherein the design and/or registration marks are applied by flexographic printing.

34. A process according to any one of claims 32-33, further comprising perforating the film before applying the adhesive, optionally wherein perforating is carried out after application of a design and/or registration mark(s).

35. A process according to any one of claims 32-34, further comprising, after sealing, cutting to produce individual sealed containers.

36. A sealed container obtainable by the process according to any one of claims 1-28 and 31-35.

37. A sealed container according to 36, wherein upon peeling off the lidding film a majority of the adhesive is retained on the lidding film, for example, at least 60 % by weight of the adhesive applied to the lidding film is retained on the lidding film following peeling off the lidding film.

38. A manufacturing system configured to carry out a process for sealing a container according to any one of claims 1 to 28 and 31-35, the system comprising a supply of containers having an opening, a supply of lidding film, a supply of adhesive and apparatus for applying adhesive to the lidding film in a selected area(s) and an apparatus for sealing the lidding film to the container.

39. The manufacturing system according to claim 33, wherein the apparatus for sealing the lidding film to the container forms the seal by the application of heat and/or pressure to the lidding film and/or container.

40. The manufacturing system according to claim 38 or 39, further comprising: (i) a first print apparatus for applying a print design and/or one or more registration marks to a surface of the lidding film, and/or (ii) a second print apparatus for applying adhesive to the lidding film in registration with the flange of the container to which the lidding film is to be sealed, and/or (iii) an apparatus for perforating the lidding film, for example, a laser perforator, and/or (iv) an apparatus for placing an article of commerce, for example, foodstuff, in the container in the opening prior to sealing, and/or (v) a cutting means for cutting the lidding film during or following sealing.

41. The manufacturing system according to any one of claims 38-40, wherein the system is configured for continuous processing and comprises conveying means for the lidding film and containers.

42. The manufacturing system according to any one of claims 38-41, wherein a plurality of containers are processed substantially simultaneously.

43. Use of a lidding film according to claims 29 or 30 in the manufacture of a sealed container.

44. A process for making a sealed container substantially as hereinbefore with reference to the accompanying drawings.

45. A lidding film substantially as hereinbefore described with reference to the accompanying drawings.

46. A sealed container substantially as hereinbefore described with reference to the accompanying drawings.

47. A manufacturing system as hereinbefore described with referent to the accompanying drawings.