Methods of producing packaging

Abstract

A method of producing a compostable moulded food packaging container 10, such as single serve sauce pots, having a cavity for receiving a foodstuff 22 and a lip 16 extending at least partially around the opening to which a compostable lid 18 can be adhered, comprises providing a thermoformable film 14 formed of a compostable material and thermoforming the cavity of the packaging container from the film at a temperature in the range of about 98°C to about 115°C. The method may further comprise peelably adhering the compostable lid, which preferably comprises cellulose and a polymer to the lip with a peelable adhesive 20, preferably a heat seal lacquer. The compostable material may be subjected to a shock annealing cooling process and may be formed of a nano-blend of two or more biodegradable polymers comprising a nanostructured first biopolymer in a matrix of a second biodegradable polymer. The compostable material may further comprise a filler and a compatibilizer.

Description

Field The present invention relates to methods of producing compostable packaging. In particular, the invention relates to a method of producing a compostable single use packaging which is specifically adapted for liquid foodstuffs, such as sauces. Background Single serve packaging is problematic from an environmental point of view, as typically not all of the components are recyclable or compostable. This can be confusing for the consumer who can be unsure how to best dispose of the packaging after use and as a result of this, the packaging is often simply placed in the general waste. Some single serve sachets or ‘dipping’ pots containing sauces (such as tomato ketchup, mayonnaise, barbeque sauce, mustard etc) in quick serve restaurants and take away outlets pose a particular problem as the sauces need to have a reasonable shelf life of between six to twelve months and are often transported long distances before being delivered to a particular restaurant or outlet. Due to the relatively small size of single serve sachets or dipping pots, these types of packaging are also difficult to recycle given the current minimum size restrictions from the Material Recycling Facilities and contamination with unused product. Therefore, whilst developing a recyclable packaging would be preferable, given the difficulties with the small product format, developing a compostable packaging would make more of a positive environmental impact in the short term. Due to the high water content in sauces, it has proven difficult for the packaging industry to provide a compostable single serve packaging which is suitable as compostable materials generally need good compatibility with moisture for the degradation process to take place. Multi-component packaging, where the user physically has to deconstruct the packaging into separate components, has been suggested and has been used for a number of foodstuffs such as fresh meat and fish. However, such packaging is unsuitable for sauces given the sticky and messy nature of sauces and the consumption environment where ease and speed of food consumption (and subsequent disposal of its related packaging) is a primary driver for the experience. There is an unmet need in the packaging industry to provide a method for producing a compostable single serve packaging. It would be desirable that such compostable single serve packaging were completely compostable, that is to say that all components were compostable. It would further be desirable to provide a compostable single serve packaging that was suitable for sauces (such as tomato ketchup) and also enable the sauces to have a long shelf life. It would also be advantageous if such single serve packaging were as easy to use as existing single serve packaging. Summary of the Invention It is one aim of the present invention, amongst others, to provide a method of producing a compostable packaging that addresses at least one disadvantage of the prior art, whether identified here or elsewhere, or to provide an alternative to existing compostable packaging. In accordance with a first aspect of the present invention, there is provided a method of producing a compostable moulded food packaging container, wherein the container has a cavity for receiving a foodstuff, an opening through which the foodstuff can be accessed, and a lip extending at least partially around the opening to which a compostable lid can be adhered, wherein the method comprises: a) providing a thermoformable film formed of a compostable material; and b) thermoforming the cavity of the packaging container from the thermoformable film at a temperature in the range of about 98 °C to about 115 °C. The method may further comprise peelably adhering a compostable lid around the opening and extending to the lip with a peelable adhesive. The lid may comprise a number of compostable materials. Preferably, the lid is formed of a cellulose and one or more polymers. The underside of lid may comprise a peelable adhesive. In certain embodiment, the peelable adhesive is formed using a heat seal lacquer. The heat seal lacquer will preferably be a biodegradable or compostable lacquer. In alternative embodiments, the peelable adhesive is a cold seal adhesive. Preferably, the compostable lid is adhered over around the opening using a heat seal lacquer extending over the lip and being subjected to a temperature of about 140 °C. In one embodiment the compostable lid is adhered over around the opening using a heat seal lacquer extending to the lip and being subjected to a temperature of about 140 °C. The heat seal adhesive may be applied at a dry coat weight in the range of about 10 gsm to about 24 gsm. Preferably, the heat seal adhesive is applied at a dry coat weight in the range of about 12 gsm to about 20 gsm. More preferably, the heat seal adhesive is applied at a dry coat weight in the range of about 14 gsm. During film casting or blowing of the container, the compostable material may be subjected to a shock annealing cooling process. The compostable material of the container may be subjected to a cooling temperature in the range of about 12 °C to about 20 °C. In certain embodiments, the method further comprises filling the cavity of the container with a foodstuff after the cavity has been formed. The film of the container will preferably be greater than about 300 pm thick. More preferably, the film of the container is greater than about 400 pm thick. Even more preferably, the film of the container is greater than about 500 pm thick. The film of the container may have a thickness in the range of about 300 pm to about 700 pm. Alternatively, the film of the container may have a thickness in the range of about 400 pm to about 700 pm. Further alternatively, the film of the container may have a thickness in the range of about 500 pm to about 700 pm. Most preferably, the film of the container is about 550 pm thick or about 690 pm thick. The food packaging will preferably further comprise a foodstuff within the cavity. Such a foodstuff may be a liquid foodstuff. The foodstuff may be a sauce, such as a condiment and may be one or more of the following: tomato ketchup, barbeque sauce, mayonnaise, mustard sauce, chili sauce, ranch dressing, curry sauce, and sweet and sour sauce. The thermoforming may be undertaken at about 4 bars and / or for about 1 second. A number of compostable materials may be used in the thermoforming process. Preferably the compostable material is obtained from Competitive Green Technologies (CGT, Leamington, ON, Canada). In one embodiment, the compostable material of the container is a material as described in WO2019 / 113713 (which is hereby incorporated herein by reference in its entirety). In another embodiment, the compostable material of the container is as described in (and is produced via a single-step extrusion process according to) WO2021 / 226722 (which is hereby incorporated herein by reference in its entirety). In one embodiment, the compostable material may be formed from a nano-blend of two or more biodegradable polymers comprising a nanostructured first biopolymer in a matrix of a second biodegradable polymer. In one embodiment, the thermoformable film is formed of a monolayer. In another embodiment, the thermoformable film is formed of two of more layers of compostable material. In certain embodiments, the two or more layers may form a laminate film. The biodegradable polymers may be selected from one, or a combination of two or more, of poly(butylene succinate) (PBS), BioPBS (bio-based PBS), poly(butylene succinate adipate) (PBSA), BioPBSA (bio-based PBSA), poly(butylene adipate-co-terephthalate) (PBAT), polyhydroxyalkanoates (PHAs), polylactide acid (PLA), poly(3-hydroxybutyrate-hydroxyvalerate) (PHBV), and a copolyester of 1,4 -butanediol, adipic and terephthalic acid (Ecoflex™). In a preferred embodiment, the biodegradable polymers comprise one or a combination of two or more, of PBAT, PBS, PHBV or PLA. The compostable material may comprise a polymeric matrix comprising a binary blend of PBS / PBS A, PBS / PBAT, BioPBSA / the copolyester of 1.4-butanediol, adipic acid and terephthalic acid or PBSA / PBAT, or a ternary blend of PLA / PBS / PBAT, PHBV / BioPBSA / the copolyester of 1 4-butanediol, adipic acid and terephthalic acid or PBSA / PBAT / PHBV, or a quaternary blend of PLA / PBS / PBAT / PHBV or PLA / BioPBS / PBAT / PHBV. The polymeric matrix may comprise PBAT and PHBV as a major component of the polymeric matrix. The compostable material may be free of ethylene vinyl alcohol (EVOH) or polyvinyl alcohol (PVOH). In certain embodiments, the compostable material further comprises a compatibilizer from peroxide or maleic anhydride-grafted biopolymers. The first biopolymer may be polybutyrate adipate terephthalate (PBAT), and the second polymer may be polybutylene succinate (PBS). The first biopolymer may be polybutylene succinate (PBS), and the second polymer may be polybutyrate adipate terephthalate (PBAT). The compostable material may further include polylactic acid (PLA). The compostable material may comprise up to about 60 percent wt. of PLA. The compostable material may further include poly(3-hydroxybutyrate-co-3 -hydroxy valerate) (PHBV). The compostable material may comprise up to about 25 percent wt. of PHBV. The compostable material may further comprise up to about 25 percent wt. of PBAT. The compostable material may further comprise up to about 0.75 phr or less of a free radical initiator. The free radical initiator may be selected from dibenzoyl peroxide, benzoyl peroxide, dicumyl peroxide, hydroperoxides and ketone peroxides. The compostable material may further include one or more fillers. Fillers are added to improve specific properties of the polymers, including tensile strength, scratch resistance, heat resistance and / or barrier function, as well as providing economic benefits and improving the ease of processing. The compostable material may include the filler up to about 60 percent wt. of filler. The filler may be selected from one or more of the following group: natural fibers from perennial grasses, cellulose and agricultural residues; inorganic mineral fillers; carbon fibers; by-products (biomass fillers) from coffee, tea and other agricultural products; and a combination thereof. In certain embodiments, the filler material is a biocarbon, also known as ‘biochar’. Biocarbon is produced from the pyrolysis of biomass. Preferably, the biocarbon comprises one or more of pyrolyzed miscanthus, pyrolyzed coffee chaff, pyrolyzed soy hull, pyrolyzed hull, pyrolyzed wood, pyrolyzed coffee ground or pyrolyzed oat hull. In another embodiment, the filler material comprises one, or a combination of two or more, of: mineral fillers, starch and / or carbon-rich fillers. The inorganic mineral fillers may include, but are not limited to, talc and clay. The carbon-rich fillers may include, but are not limited to, graphite, graphene, and graphene oxides. The starch-based fillers may be derived from corn, potato and / or wheat. In an additional embodiment, the filler material may comprise a hybrid filler material comprising biocarbon and one or more of inorganic mineral fillers, starch and / or carbon-rich fillers. Preferably, the hybrid filler material comprises biocarbon and one or more of starch, talc and / or graphite. The filler material may comprise up to about 20 wt% of the polymeric matrix composite, or up to about 30 wt%, up to about 40 wt%, up to about 50 wt%, up to about 60 wt% or up to about 70 wt%. Preferably, the filler comprises up to about 40 wt% of the polymeric matrix composite, wherein the remainder of the composite comprises the biodegradable polymers. In some embodiments, the compostable material may additionally comprise a compatibilizer. Compatibilizers can be used to facilitate the physical and chemical interactions between the polymer chains and therefore improve miscibility in a polymeric blend or polymeric matrix. In one embodiment, the compatibilizer comprises a reactive functional group, such as a maleic anhydride or an epoxy group. In a specific embodiment, the compatibilizer comprises maleic anhydride-grafted biopolymers. In a further embodiment, the compatibilizer comprises a free radical initiator. A free radical initiator refers to a substance that can produce a free radical species under mild conditions and promote a free radical reaction. The free radical initiator may include, but is not limited to, peroxides, superoxide, hydroxyl radicals and / or singlet oxygen. In a preferred embodiment, the compatibilizer comprises peroxide and / or maleic anhydride grafted biopolymers. The compostable material may be produced by first manufacturing a nano-blend of two or more biodegradable polymers having a nanostructured first biodegradable polymer in a matrix of a second biodegradable polymer and includes melting the first and the second biodegradable polymers in the presence of an amount of a free radical initiator, thereby manufacturing the nano-blend. In one embodiment the amount free radical initiator is 0.75 phr or less and the two or more biodegradable polymers are selected from: Poly lactide (PLA), poly(butylene succinate) (PBS), poly(butylene adipate-co-terephthalate) (PBAT), and polycaprolactone (PCL) and polyhydroxyalkanoate (PHA(s)), poly (3 -hydroxy)butyrate (PHB) and poly(3-hydroxybutyrate- hydroxyvalerate) (PHBV). The compostable material may further comprise an optional free radical initiator selected from: dibenzoyl peroxide, benzoyl peroxide, dicumyl peroxide, hydroperoxides, ketone peroxides or a combination thereof. The compostable material preferably further comprises Poly lactide (PLA) and / or poly(3-hydroxybutyrate- hydroxy valerate) (PHBV). An advantage of using the compostable material is that the decomposition or composting of a container made from this material does not produce any microplastics. Similarly, the carbon emissions emitted at the end of life (whatever the end of life may be: incineration, composting, decomposition, etc.) would be biogenic carbon emissions rather than new carbon emissions, i.e. does not contribute to an increase of carbon dioxide in the atmosphere. In one embodiment, the thermoformable film does not comprise microplastics. In another embodiment, the thermoformable film does not release microplastics when disposed of at the end of life of the container. In accordance with another aspect of the present invention, there is provided a compostable moulded food packaging container produced according to the method as herein above described. The invention is described below, by way of example only, with reference to the accompanying figures in which: Figure 1 is a schematic diagram of the process employed to form a sheet of compostable material from a nano-blend of the two or more biodegradable polymers. Figure 2 is a perspective view of a thermoforming tool that can be used to form a compostable container from a sheet of compostable material. Figure 3 is a perspective cut-away view of an alternative embodiment of a compostable container in accordance with the present invention. Figure 4 is a schematic cross-section of the lip of a compostable container as shown in Figure 3. Figure 5 is a graph and table showing the Water Vapor Transmission Rate (WVTR) of a compostable container formed of various nano blend resins compared to a standard polypropylene (PP) container. This test was carried out at 38 °C ± 2 °C and 90% ± 5 % relative humidity (RH). Figure 6 is a graph and table showing the Oxygen Transmission Rate (OTR) of a compostable container formed of various nano blend resins compared to a standard polypropylene (PP) container. This test was carried out at 20 °C ± 2 °C and 65% ± 5 % relative humidity (RH). Examples Example 1 - Forming a Film of Compostable Material Generally speaking, chemically reactive extrusion in a twin-screw extruder is used so as to compound a blend of bio-resins and natural fillers to provide a compounded nano-blend resin 1 which is then forced through the extrusion die 2 to form a film. The twin-screw extrusion used to form the nano-blend resin can be carried out as described in WO2019 / 113713 and / or WO2021 / 226722. Such a nano-blend resin was obtained from CGT (Leamington, ON, Canada). Briefly, the process for forming the nano-blend resin is included below. More specifically, to form the nano-blend resin bio-composites are compounded in a twin-screw extruder (Leistritz Micro-27, Germany) equipped with screw diameter of 27 mm and an L / D ratio of 48 in one-step extrusion. In the case of bioplastics / 40% filler system, the bioplastics (dried in an oven at 80 °C for 24 hr) were added in the main feeder and hybrid fillers (dried in 80 °C for 24 hr) are added in the side feeder. In the case of bioplastics / up to 30% filler system, the bioplastics (dried in an oven at 80 °C for 24 hr) and hybrid fillers were mixed and added in the main feeder to prepare pellets. A range of bio-composites were assessed having varying quantities of PBS, PBAT and PHBV (for example PBS 60% wt„ PBAT 20% wt„ PHBV 20% wt. or PBS 40% wt„ PBAT 20% wt., PHBV 40% wt.) in combination with one or more fillers and / or polymer initiators. The feeding speed and extrusion screw speed were 5-8 kg / h and 100 rpm, respectively. Other compounding machines have the same function of twin-screw extruder, including but not limited to Haake mixers or the like, micro-compounders with integrated extrusion and injection moulding systems (i.e. DSM micro injection moulding or Arburg injection moulding), or in any extrude and injection moulding systems can be used to process the biocomposites. When an extruder is used, which is the preferred method of processing, strands are produced in a continues process which can be pelletized and further processed by other process method such as injection moulding, three roll calendaring, film blowing or the like. The extrusion parameters and additive concentrations used for fabrication of compatibilized composites are listed below in Table 1. Parameter Conditions Processing temperature 120 to 250 °C Feed Rate 5-8 kg / h Screw Speed 20- 150 rpm Residence time 0.2 -10 min Fillers 1-40wt% The extruded pellets are shaped into a film by either film blowing or film casting. The film can then be formed or cut into the desired blank shape. The thickness of the films and sheets will typically be in the range of 300 to 700 pm. In trials, the thickness of films have been about 550 pm for substantially cuboidal (rectangular / square) trays and about 690 pm for substantially cylindrical (round) trays. Figure 1 shows a schematic diagram of the overall process for forming a film / sheet of compostable material via extrusion from the extruded nano-blend resin. The melted nanoblend polymer 3 is passed between a nip roller 4 and cooling roller 5 in order to cast a film 6 of the compostable material. During the film casting, a shock-annealing process of cooling the bio-resin mix from the die to the rollers is employed advantageously allowing the maintenance of the gas / moisture barrier properties to be retained and improved. The cooling roller 5 reduces the bio-resin mix to a cooling temperature in the range of 12 °C and 20 °C. During the film casting, the bio-resin mix is transformed into a film / sheet of 550 microns that can then be used on thermoforming equipment. Example 2 - Thermoforming Trays from the Film of Compostable Material Thermoforming trials were conducted on the film of compostable materials as described in Example 1. Figure 2 shows an example of a plug assist tool where the tool 100 is formed of a flat base 102 having a cavity 103 which is shaped to the external dimensions of the desired tray 106. This cavity is cooled with cooling water to remove the heat energy from the compostable material when being formed. A press 108, having a plug 104 extending downwardly towards the interior of the shaped cavity, operates in a vertical direction to push the pre heated compostable material into the cavity 102. Compressed air is then used to mould the compostable material to the cavity shape, thus thermoforming the tray. The tray is thermoformed in the temperature range of 98°C to 115°C, which is lower than typically used for thermoforming polymers into trays (and other articles). This lower temperature not only reduces the energy required to form the trays, but also advantageously allows the maintenance of the gas / moisture barrier properties of the film to be retained and improved. In addition, the lower thermoforming temperature improves the efficiency of cooling after the thermoforming process. Prior to thermoforming of the tray, the film is preheated, then formed into trays, which are cooled before being filled with product, sealed with a printed top film and placed into a box at high speed. Example 3 - Lidding Film Trials The purpose of the trials was to investigate whether certain preferred lidding films were compatible with heat sealing against the preferred compostable material used for the tray and whether a biodegradable adhesive provided a strong enough bond when activated during the thermoforming process. Test films used within the trials are detailed in Table 2 below. Current foil lidding film Baseline Pap 40 / PBS 20 / MetPAP 23 / PBS 20 Lid Film Pap 40 / PBS 20 / TransPAP 23 / PBS 20 Lid Film Pap 40 / MetCellulose 23 / Cellophane 20 Lid Film Pap40 / Cellulose 19 / Cellophane 20 Lid Film 5gsm Paper / 23mu Cellulose / 30mu Bio-HSL Lid Film Table 2 Test preparation and parameters were as follows: Test Strip: 25mm x 150mm; Sealing Temperature: 120°C; Sealing Pulse: 1 sec; Sealing Pressure: 450lbf; Test Method: ASTM D1876 (T Peel); and Peel Rate: 300mm.min-1. Example 4 - Pilot Trials Pilot trials were conducted so as to test different parameters from forming the film, thermoforming trays, lidding and adhesives so as to establish the best temperature parameters for thermoforming and sealing temperatures on a production line for the production of a sauce container. Trial 1 Pre-heating of the film produced by the casting process of Example 1 (Figure 1) prior to thermoforming trays of containers was performed at the following temperatures (°C): 103 108 111 115 116 120 103 108 111 115 116 120 The sealing of the lid to the tray was performed at the following temperature (°C): 150 In this trial, preconditioning was turned off. It was found that the compostable material was sticking to the pre-heating plates and the material was melting. A ‘shark skin’ effect was found in the trays. Pilot 2 10 A second pilot trial was conducted to reduce pre-heating thermoforming temperatures by 5°C and reduce the sealing temperature. The thermoforming of trays was performed at the following temperatures (°C): 98 103 106 110 111 115 98 103 106 110 111 115 The sealing of the lid to the tray was performed at the following temperature (°C): 140 The reduction of the thermoforming temperature to between 98 °C and 115 °C and reduced sealing temperature of 140 °C resulted in no sticking / melting of the compostable material and achieved adequate sealing. Example 5 - Compostable Sauce Container Figure 3 shows a compostable container 10 in accordance with the present invention. The container 10 is formed of a single compostable material 14 which has moisture and gas barrier properties. The container 10 is formed of a compostable thermoformed tray 12. The thermoformed tray 12 has a lip 16 extending outwardly and around the opening of the tray 12. A compostable lid 18 is adhered to the compostable material 14 around the lip 16 by means of a peelable adhesive 20. The container 10 has a cavity in which a liquid foodstuff product 22 (such as tomato ketchup) is received. Figure 4 shows a cross section of the area indicated X in Figure 3 and shows the layering of the various components in the lip area to which the lid 18 is adhered. In Figure 4, the cross section X of a compositable container is shown which is formed of a thermoformed composable material 14. A compostable lid 18 is adhered to the barrier film 14 by means of a peelable adhesive 20. In an alternative embodiment than that shown in Figures 3 and 4, the thermoformed compostable material 14 may be formed by the lamination of multiple layers of the material. Preferably, the thickness of the compostable material 14 is in the range of about 100 pm to about 600 pm, for example in the range of about 400 pm to about 600 pm. Most preferably, the thickness of the compostable material 14 is about 400 pm. Typically, the lid 18 will contain graphics and other printed material indicating the foodstuff in the container and instructions for peeling the lid and disposal after the use of the container. The graphics or other printed material will preferably be made from compostable and food safe inks. When the Water Vapor Transmission Rate (WVTR) and Oxygen Transmission Rate (OTR) of compostable sauce containers formed from various nano-blend resins was assessed against a standard PP sauce container (Figures 5 and 6). WVTR for all bio-resin pots is higher than for the current standard PP container. The OTR for some of the compostable containers made from each nano blend resin was better than the OTR of the barrier PP / EVOH / PP pots used as references. The WVTR and OTR combined were acceptable to reach a shelf life of a sauce contained in all the compostable containers of approximately 100 days for Tomato Ketchup (Figure 5). Despite the increase in WVTR of the compostable containers compared to standard PP containers, the compostable containers are a viable solution for the storage of a liquid condiment. The OTR results especially prevent oxidation of the sauce within the container over the 100 days of measured shelf life (Figure 6). The containers made from a selection of nano blend resins also performed better and had a lower OTR compared to a standard PP container. The compostable material 14 may comprise one, or a combination of two or more, biodegradable polymers. The compostable material 14 may comprise a polymer blend composed of two or more polymers. In certain embodiments, the material comprises a polymeric matrix composite, wherein the polymeric matrix composite comprises one or more biodegradable polymers. It will be apparent to the skilled addressee that a range of biodegradable materials can be selected, provided that it exhibits the correct barrier properties required for the foodstuff to be contained in the compostable container. For example, the biodegradable polymers may be selected from one, or a combination of two or more, of poly(butylene succinate) (PBS), BioPBS (bio-based PBS), poly(butylene succinate adipate) (PBSA), BioPBSA (bio-based PBSA), poly(butylene adipate-co-terephthalate) (PBAT), polyhydroxyalkanoates (PHAs), polylactide (PLA), poly(3-hydroxybutyrate-hydroxyvalerate) (PHBV) and a copolyester of 1,4 -butanediol, adipic and terephthalic acid (Ecoflex™). In a preferred embodiment, the biodegradable polymers comprise one or a combination of two or more, of PBS, PBAT, PHBV or PLA. Preferably, the nano-blend resin used to form the compostable material 14 is obtained from CGT (Leamington, ON, Canada). The optional features set out herein may be used either individually or in combination with each other where appropriate and particularly in the combinations as set out in the accompanying claims. The optional features for each aspect or exemplary embodiment of the invention as set out herein are also to be read as applicable to any other aspect or exemplary embodiments of the invention, where appropriate. In other words, the skilled person reading this specification should consider the optional features for each exemplary embodiment of the invention as interchangeable and combinable between different exemplary embodiments. Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference. All of the features disclosed in this specification (including any accompanying claims, and drawings), and / or all of the steps of any method or process so disclosed, may be combined 5 in any combination, except combinations where at least some of such features and / or steps are mutually exclusive. Each feature disclosed in this specification (including any accompanying claims, and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each 10 feature disclosed is one example only of a generic series of equivalent or similar features. The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

1. A method of producing a compostable moulded food packaging container, wherein the container has a cavity for receiving a foodstuff, an opening through which the foodstuff can be accessed, and a lip extending at least partially around the opening to which a compostable lid can be adhered, wherein the method comprises:a) providing a thermoformable film formed of a compostable material; andb) thermoforming the cavity of the packaging container from the thermoformable film at a temperature in the range of about 98 °C to about 115 °C.

2. The method of claim 1, wherein the method further comprises peelably adhering a compostable lid around the opening and extending to the lip with a peelable adhesive.

3. The method of claim 2, wherein the lid comprises cellulose and a polymer.

4. The method of any one of claims 2 to 3, wherein the peelable adhesive is a heat seallacquer.

5. The method of any one of claims 2 to 4, wherein the compostable lid is adhered around the opening and extending over the lip at a temperature of about 140 °C.

6. The method of any one of claims 1 to 5, wherein thermoformable film is formed via extrusion followed by film casting or blowing.

7. The method of claim 6, wherein during film casting or blowing, the compostable material is subjected to a shock annealing cooling process.

8. The method of either claim 6 or 7, wherein the compostable material is subjected to a cooling temperature in the range of about 12 °C to about 20 °C.

9. The method of any one of claims 1 to 8, wherein the method further comprises filling the cavity of the container with a foodstuff after the cavity has been formed.

10. The method of any one of claims 1 to 9, wherein the film is in the range of about 300 pm to about 700 pm thick.

11. The method of any one of claims 1 to 10, wherein the compostable material is formed of a nano-blend of two or more biodegradable polymers comprising a nanostructured first biopolymer in a matrix of a second biodegradable polymer.

12. The method of claim 11, wherein the two or more biodegradable polymers are selected from: poly(butylene succinate) (PBS), BioPBS (bio-based PBS), poly(butylene succinate adipate) (PBSA), BioPBSA (bio-based PBSA), poly(butylene adipate-co-terephthalate) (PBAT), polyhydroxyalkanoates (PHAs), polylactide (PLA), poly(3-hydroxybutyrate-hydroxyvalerate) (PHBV), and a copolyester of 1,4 -butanediol, adipic and terephthalic acid (Ecoflex™).

13. The method of claim 11 or 12, wherein the compostable material further comprises a filler.

14. The method of claim 13, wherein the filler is selected from one or more of the following group: natural fibers from perennial grasses, cellulose and agricultural residues; inorganic mineral fillers; carbon fibers; by-products (biomass fillers) from coffee, tea and other agricultural products; and a combination thereof.

15. The method of claims 11 to 14, wherein the compostable material further comprises a compatibilizer.

16. The method of claim 15, wherein the compatibilizer comprises a reactive functional group or an epoxy group.

17. The method of claims 11 to 16, wherein the compostable material further comprises a free radical initiator.

18. The method of claim 17, wherein the free radical initiator is selected from the following group: dibenzoyl peroxide, benzoyl peroxide, dicumyl peroxide, hydroperoxides and ketone peroxides.

19. The method of any claims 1 to 18, wherein the thermoforming is undertaken using compressed air at about 4 bars for about 1 second.

20. A compostable moulded food packaging container produced according to the method of claims 1 to 19.

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