Packaging and manufacturing methods

Abstract

The present invention relates to a compostable food package comprising: a) a compostable formed tray having an internal cavity for receiving food, an opening through which the food is accessible, and a lip extending at least partially around the opening; b) the compostable formed tray forms a compostable barrier, or the compostable formed tray further comprises a compostable barrier film stretched over and adhered to the internal cavity and lip of the tray by a paper and biofilm heat seal adhesive; and c) a compostable lid releasably adhered around the opening and extending to the lip using a peelable adhesive. The package is particularly useful for producing single-use sauce pots for fast food restaurants and takeout outlets, but may also be used for single-use cooking sauces and concentrated stocks. The present invention also relates to a method for producing such a compostable food package.

Description

[Technical Field]

[0001] The present invention relates to compostable packaging and methods for making such packaging. In particular, the present invention relates to compostable disposable packaging that is especially adapted for liquid food products such as sauces. [Background technology]

[0002] Single-use packaging is problematic from an environmental perspective because not all components are recyclable or compostable. This can confuse consumers, who are unsure how best to dispose of the packaging after use. As a result, the packaging often ends up in the general trash. Single-use sachets and "dipping" pots containing sauces (e.g., tomato ketchup, mayonnaise, barbecue sauce, mustard) served at fast food restaurants and takeout outlets present a particular challenge because these sauces must have an appropriate shelf life of six to 12 months and are often transported long distances before being delivered to a specific restaurant or store. Because single-use sachets and dipping pots are relatively small, these types of packaging are difficult to recycle, given the differences in materials used and the risk of contamination from unused product. Therefore, while developing recyclable packaging is desirable, developing compostable packaging would likely have a better environmental impact in the short term, given the challenges associated with small product formats.

[0003] Due to the high moisture content of the source, it has proven difficult for the packaging industry to provide suitable compostable single-use packaging, as compostable materials generally begin to decompose rapidly in the presence of moisture.

[0004] Multi-component packaging, which requires the user to physically disassemble the packaging into its individual components, has been proposed and is used for some foods such as fresh meat and fish. However, the sticky and messy nature of sauces makes such packaging unsuitable for sauces, given a consumption environment where ease and speed of food consumption (and the associated subsequent disposal of the packaging) are key drivers of the experience.

[0005] There is an unmet need in the packaging industry to provide compostable single-use packaging. It is desirable that such compostable single-use packaging be fully compostable, i.e., all components are compostable. It is further desirable to provide compostable single-use packaging suitable for sauces (such as tomato ketchup) that can also extend the shelf life of the sauce. It would also be advantageous if such single-use packaging were as easy to use as existing single-use packaging. Summary of the Invention [Problem to be solved by the invention]

[0006] One of the objects of the present invention, whether identified herein or elsewhere, is to provide, among other things, compostable packaging that addresses at least one shortcoming of the prior art, or to provide an alternative to compostable packaging. [Means for solving the problem]

[0007] According to a first aspect of the present invention there is provided a compostable food package comprising: a) a compostable molded tray having an interior cavity for receiving a food product, an opening through which the food product can be accessed, and a lip extending at least partially around the opening; b) a compostable molded tray forming a compostable barrier, or a compostable molded tray including a compostable barrier film stretched over and adhered to the interior cavity and lip of the tray by a paper and biofilm heat seal adhesive; c) a compostable lid releasably adhered around the opening and extending to the lip using a peelable adhesive; Includes:

[0008] The barrier or barrier film may be formed from a number of materials that will be apparent to those skilled in the art. The barrier or barrier film may be formed from a compostable bio-resin material. Compostable bio-resin materials, particularly those suitable for the present invention, will be apparent to and well understood by those skilled in the art. The barrier or barrier film may include polyimide and / or epoxy resin.

[0009] The barrier or barrier film may be formed of a single layer or multiple layers. When the barrier film is formed of multiple layers, each layer may be applied separately or simultaneously. The barrier or barrier film may be extruded into a sheet.

[0010] The lid may include some compostable materials. Preferably, the lid is formed of cellulose and one or more polymers. The underside of the lid may include a peelable adhesive. In certain embodiments, the peelable adhesive is formed using a heat-seal lacquer. The heat-seal lacquer is preferably a biodegradable or compostable lacquer. In an alternative embodiment, the peelable adhesive is a cold-seal adhesive.

[0011] The heat seal adhesive may comprise a polyurethane, which may include one or more of 5-chloro-2-methyl-4-isothiazolin-3-one and / or 2-methyl-4-isothiazolin-3-one.

[0012] Where the compostable molded tray includes a compostable barrier film stretched over and adhered to the interior cavity and lip of the tray by a paper and biofilm heat seal adhesive; The compostable molded fiber trays may be compostable molded fiber trays. The compostable molded fiber trays may be dry molded fiber trays. Alternatively, the molded fiber trays may be wet molded or semi-wet molded. The heat seal adhesive may be applied to a dry coat weight in the range of about 10 gsm to about 24 gsm. Preferably, the heat seal adhesive is applied to a dry coat weight in the range of about 12 gsm to about 20 gsm. More preferably, the heat seal adhesive is applied to a dry coat weight in the range of about 14 gsm. Preferably, the barrier film may have a thickness of about 110 μm or more. More preferably, the barrier film has a thickness of about 135 μm or more. Most preferably, the barrier film has a thickness of about 150 μm or more. In a highly preferred example, the thickness of the barrier film may be in the range of about 150 μm to about 170 μm. The barrier film may be extruded into a sheet and / or directly onto a molded fiber tray. The barrier film may also be at least partially spray coated onto the tray. - The barrier film is designed to withstand temperatures of approximately 100 o C ~ approx. 110 o It may be thermoformed in the range of C.

[0013] If the compostable molded tray forms a compostable barrier, The thickness of the compostable barrier may be in the range of about 100 μm to about 600 μm, preferably in the range of about 400 μm to about 600 μm. The thickness of the compostable barrier may be about 400 μm and may be formed in three layers, each about 130 μm thick. Each layer may be made of a compostable bio-resin material. The intermediate layer may comprise a compostable material that is an oxygen scavenger, for example, the intermediate layer may comprise a plant by-product such as that derived from coffee bean husks. - Compostable barriers are approximately 100 o C ~ approx. 170o At a temperature in the range of about 100°C, preferably o C~about 120 o C, most preferably at about 105 o C~about 120 o It may be thermoformed in the range of C. The compostable barrier may be thermoformed with a thermoforming residence time of less than about 1000 ms, preferably less than about 800 ms, and most preferably less than about 700 ms. The method includes pressing a lid onto the opening under heated conditions to seal the cavity with the lid, preferably for about 200 o At temperatures below about 170°C, more preferably o At temperatures below 160°C, most preferably at temperatures below 160°C o C~170 o This may include heat sealing at a temperature in the range of C.

[0014] If the compostable molded tray forms a compostable barrier, The compostable molded tray may be impregnated with a compostable barrier material, for example, by interspersing the barrier material with the fibers in or near the region of the internal cavity of the compostable molded fiber tray. This may refer to the compostable molded tray and the compostable barrier being integrally formed or provided.

[0015] In an embodiment related to the first aspect, there is provided a compostable food package comprising: a) a compostable molded fiber tray having an interior cavity for receiving food, an opening through which the food is accessible, and a lip extending at least partially around the opening; b) a spray-coated compostable barrier film stretched over and adhered to the interior cavity and lip of the tray; and c) a compostable lid that is releasably adhered around the opening and extends to the lip using a peelable adhesive Includes:

[0016] In yet another embodiment related to the first aspect, there is provided a compostable food package comprising: a) a compostable molded fiber tray having an interior cavity for receiving food, an opening through which the food is accessible, and a lip extending at least partially around the opening; b) a compostable barrier material impregnated throughout the molded fiber tray; c) a compostable lid releasably adhered around the opening and extending to the lip using a peelable adhesive; Includes:

[0017] The food package preferably further includes a food product within the interior cavity. Such food product may be a liquid food product. The food product may be a sauce, such as a condiment, and may be one or more of tomato ketchup, barbecue sauce, mayonnaise, mustard sauce, chili sauce, ranch dressing, curry sauce, and sweet and sour sauce.

[0018] According to a second aspect of the present invention there is provided a method of producing compostable food packaging, the method comprising: a) providing a compostable molded tray having an interior cavity for receiving a food product, an opening through which the food product can be accessed, and a lip extending at least partially around the opening; b) providing a compostable molded tray comprises forming a compostable barrier film, or the method further comprises applying and / or forming and adhering a compostable barrier film over the interior cavity and lip of the tray by heat sealing the paper and biofilm; c) providing a compostable lid and adhering the lid around the opening and at least a portion of the lip with a compostable peelable adhesive; d) pressing the lid onto the opening under heated conditions and heat sealing the cavity with the lid; Further includes:

[0019] Before step c), a liquid food product may be placed in the cavity.

[0020] Step d) is approximately 120 o C and / or at about 450 lbf and / or for about 1 second.

[0021] Where the method includes applying and / or forming and adhering a compostable barrier film, - The bond strength between the barrier film and the tray is stronger than the bond strength created between the barrier film and the compostable lid by the heat seal adhesive. - The barrier film may be applied to the interior cavity and lip of the tray by directing hot air at the film and applying negative pressure to the exterior of the tray. The hot air is applied at a temperature of approximately 120 o C~about 140 o C, but preferably about 136 o In another example, hot air is in the range of about 100 o C ~ approx. 110 o The hot air may be applied using a hot air gun. The hot air gun may be moved from a distance of about 200 mm from the barrier film to a distance of about 100 mm from the barrier film in a maximum of about 2 seconds to about 4 seconds. The hot air gun may be moved from a distance of about 190 mm from the barrier film to a distance of about 85 mm from the barrier film in a maximum of about 4 seconds. The barrier film may be at least partially applied to the interior cavity and lip of the tray by spray coating.

[0022] Providing compostable molded trays creates a compostable barrier, - Compostable barriers are approximately 100 o C ~ approx. 170 o At a temperature in the range of about 100°C, preferably o C~about 120 o C, most preferably at about 105 o C~about 120 o It may be thermoformed in the range of C. The compostable barrier may be thermoformed with a thermoforming residence time of less than about 1000 ms, preferably less than about 800 ms, and most preferably less than about 700 ms. - Pressing is preferably about 200 o At temperatures below 170°C, more preferably o At temperatures below 160°C, most preferably at temperatures below 160°C o C~170 o The reaction may be carried out at a temperature in the range of 0.5 to 100°C.

[0023] If the compostable molded tray forms a compostable barrier, The compostable molded fiber tray may be impregnated with a compostable barrier material, for example, by interspersing the barrier material on the fibers in or near the region of the interior cavity of the compostable molded fiber tray. The compostable molded tray and the compostable barrier material may be integrally formed.

[0024] In an embodiment related to the second aspect, there is provided a method of making a compostable food package, the method comprising: a) providing a compostable molded fiber tray having a cavity for receiving a food product, an opening through which the food product can be accessed, and a lip extending at least partially around the opening; b) applying and / or forming a compostable barrier film onto the interior cavity and lip of the tray by spray coating; c) providing a compostable lid and adhering the lid around the opening and at least a portion of the lip with a compostable peelable adhesive; d) pressing the lid onto the opening under heated conditions and heat sealing the cavity with the lid; Further includes:

[0025] In an alternative embodiment to the second aspect, there is provided a method of making a compostable food packaging, the method comprising: a) providing a compostable molded fiber tray having an interior cavity for receiving a food product, an opening through which the food product can be accessed, and a lip extending at least partially around the opening; b) impregnating the entire tray with a compostable barrier material; c) providing a compostable lid and adhering the lid around the opening and at least a portion of the lip with a compostable peelable adhesive; d) pressing the lid onto the opening under heated conditions and heat sealing the cavity with the lid; Further includes:

[0026] The method of the second aspect (and related embodiments) may be used to produce compostable food packaging according to the first aspect (and related embodiments).

[0027] The invention will now be described by way of example with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0028] [Figure 1] 1 is a perspective cutaway view of an embodiment of a compostable package according to the present invention. FIG. [Figure 2] 2 is a schematic cross-sectional view of the compostable packaging in region X shown in FIG. 1. [Figure 3] Photographs of the application of barrier film to a 3D molded fiber tray using an SLA thermoforming tool: (A) shows the SLA thermoforming tool, (B) shows the formed film on the top and bottom after heating at 75% for 2 seconds, and (C) shows the formed film after heating at 75% for 5 seconds. [Figure 4] A perspective view of the plug-assist tool used to evaluate the suitability of applying a barrier film to a 3D molded fiber tray. [Figure 5] FIG. 1 is a schematic diagram of the process employed to apply a barrier film to a 3D molded fiber tray. [Figure 6]Photographs of a 150 μm barrier film deformed and applied to a transparent 3D molded tray. (A) and (B) are top views of the combined film and tray, and (C) and (D) are side views of the combined film and tray. [Figure 7] 1 is a graph showing the water vapor transmission rate (WVTR) results of various barrier films tested during the study. [Figure 8] 1 is a graph showing the oxygen transfer rate (OTR) results of various barrier films tested during the study. [Figure 9] 1 is a graph showing peel test results for lidding films applied to lined pots tested during the study. [Figure 10] 1 is a graph plotting lid peel benchmarks for current plastic 3D molded trays along with target adhesive strengths. [Figure 11] 1 is a graph showing the adhesive strength of a barrier liner to a fiber pot in grams of adhesive. [Figure 12] FIG. 2 is a perspective cutaway view of another embodiment of a compostable package according to the present invention. [Figure 13] FIG. 13 is a schematic cross-sectional view of the compostable packaging shown in FIG. 12. DETAILED DESCRIPTION OF THE INVENTION

[0029] Example 1 Compostable Sauce Container Figure 1 illustrates a compostable container according to the present invention. The container 10 is formed of a compostable fiber molded tray 12 whose interior surface is covered with a compostable barrier film 14. The molded tray 12 has an outwardly extending lip 16 around the opening of the tray, with the barrier film 14 extending over the lip 16. A compostable lid 18 is adhered to the barrier film 14 around the lip 16 by a peelable adhesive 20. The container 10 illustrated in Figure 1 also has a liquid food product 22 (such as tomato ketchup) placed within the tray 12. Figure 2 illustrates a cross-section of the area designated X in Figure 1, showing the various component layers in the lip area to which the lid 18 is adhered.

[0030] The forming tray 12 may be formed from any compostable material and may be wet or dry fiber molded. In one embodiment, the forming tray 12 is pre-formed into the desired shape before the barrier film 14 is attached or applied to its inner surface. In another embodiment, the forming tray 12 is pre-formed into the desired shape at the same time that the barrier film 14 is applied to the inner surface, i.e., the tray 12 and barrier 14 are molded simultaneously. In certain embodiments, an adhesive (not shown) is used between the barrier film 14 and the forming tray 12. In other embodiments, no adhesive is used between the barrier film 14 and the forming tray 12, and the barrier film 14 is adhered to the inner surface of the forming tray 12 by a molding or pressing process, or by spraying the barrier film 14 directly onto the forming tray 12.

[0031] The molded tray may be formed using a dry molding method of a fibrous substrate utilizing cellulose fibers. Such a method can form a multilayered cellulose blank structure, the method comprising: forming a multilayered cellulose blank structure from at least a first layer of dry molded cellulose fibers and a second layer of a cellulose fibrous web structure by placing at least the first and second layers in a superposed relationship and contacting the at least first and second layers with each other in the superposed relationship; placing the multilayered cellulose blank structure in a mold; and forming a cellulose product from the multilayered cellulose blank structure in the mold by heating the multilayered cellulose blank structure to a molding temperature in the range of about 100°C to about 300°C and pressing the heated multilayered cellulose blank structure at an isostatic molding pressure of at least about 1 MPa, preferably 4 to 20 MPa, to form the multilayered cellulose blank structure into a two-dimensional or three-dimensional fibrous composite structure having a single layer configuration. Alternatively, the formed tray may be formed by a method utilizing a web of fibrous cellulosic material derived from wood pulp, the web being suitable for three-dimensional forming to form a packaging product, the web comprising greater than about 40% by weight softwood chemical pulp and at least one strength enhancing agent, the web having a basis weight of about 400 g / m 2 and the cellulosic fibers of the softwood chemical pulp contain greater than about 9% fiber curl.

[0032] Alternatively, the molded trays may be formed using a wet or semi-wet molding method of a fibrous substrate utilizing cellulose fibers, in which the wet or semi-wet cellulose material is conveyed to a mold and formed into a 2D or 3D shape using a forming tool to form a three-dimensional product from the wet or semi-wet cellulose material. Forming may be accomplished by thermoforming or other forming methods in which the cellulose material is molded to the shape of a mold and dried.

[0033] The barrier film 14 may be formed from any suitable compostable film having suitable moisture and oxygen barrier properties. Those skilled in the art will appreciate that the moisture and oxygen barrier properties depend on the form and type of food held within the container. Typically, the container is used for fluid foods with a relatively high moisture content, such as tomato ketchup. The moisture properties should prevent moisture from escaping from the food through the substrate used to form the molded tray. The oxygen barrier properties should prevent oxygen from entering the container to prevent undesirable oxidation of the food.

[0034] The barrier film 14 may be formed from a number of materials. The barrier film may be formed from a compostable bio-resin material. As an example, the barrier film 14 may be formed from one or more layers of modified polybutylene succinate (PBS).

[0035] The lid 18 may be formed from several materials. Preferably, the lid 18 is formed from a cellulose and polymer composite. More preferably, the lid 18 is formed from a cellulose and polymer resin or cellulose and PBS composite. The cellulose may be methylcellulose or other variants of cellulose. Typically, the lid includes graphics or other printed material identifying the food within the container, as well as instructions for removing the lid and for disposal after use of the container. The graphics or other printed material are preferably made from compostable, food-safe inks.

[0036] The adhesive may be a food-safe, compostable heat seal.

[0037] Example 2 Thermoforming Test Thermoforming tests were conducted on a variety of barrier liners to evaluate the best method and liner for use in conjunction with pre-formed 3D dry-molded trays.

[0038] Two films were supplied for thermoforming testing; the first was a 110 μm composite film formed from layers of 30 μm / 50 μm / 30 μm, and the second was a 150 μm composite film formed from layers of 50 μm / 50 μm / 50 μm.

[0039] The film thicknesses described herein are merely examples, and in some tests, film thicknesses ranging from about 150 μm to about 170 μm were used.

[0040] Phase 1 - Thermal Properties (110µm Film) As shown in Figure 3, the test results indicate that the film does not thermoform like conventional films. The main observation is that the film becomes brittle when heated excessively or for a long period of time. Furthermore, from the beginning of this phase, it was anticipated that a plug assist would be required to fully form the liner into the pot, and that vacuum alone would not be sufficient. SLA thermoforming tooling was used.

[0041] Phase 2 - Plug-assisted molding (110 μm film) To improve the forming rate, plug-assist tools were machined to apply pressure to the corners of the film. Figure 4 shows an example of a plug-assist tool. The tool 100 consists of a flat base 102 with a mold cavity 104 shaped to the exterior dimensions of a preformed tray 106, and a press 108 with a plug 110 extending downward into the interior mold cavity. The plug is shaped to the interior dimensions of the preformed tray 106. In use, the press 108 operates vertically, forcing the film (not shown) into the preformed tray as the plug 110 presses against the mold cavity 104. Unfortunately, this approach was deemed unsuccessful because, due to the film's temperature sensitivity and crystallization, by the time the plug reached the mold (after the heater platen retracted), the film had already cooled and was no longer formable.

[0042] Phase 3 - Hot Air Gun Approach (110µm Film) Due to the sensitivity of the film formation, a hot air gun was used to evaluate whether this method would be useful for forming a barrier film on the interior surface of preformed trays. Testing showed that cracks occurred above 140°C, the film formed well between 120°C and 140°C, and poorly formed below 120°C.

[0043] Alternative tests were conducted in the range of about 100°C to about 110°C, which also proved to form well.

[0044] During testing, a hot air gun approach was used to bring the film to temperature in a short time (2-4 seconds). The concept is that a positive heat flow to the film, assisted by a vacuum through the tray, not only aids in formation, but also occurs within a short (and controllable) cycle time. This approach resulted in approximately 70% formation of a 110 μm film in the pot.

[0045] Phase 4a - Positive Pressure Test (110µm Film) Since the hot air gun molding approach showed promising results, it was anticipated that applying high-density pressure and a high-temperature airflow during molding would ultimately stretch / flow the film to every corner. Positive pressure molding of a 110 μm film confirmed that this approach could lead to improved performance. A molding rate of 81% was achieved. Furthermore, the positive pressure approach resulted in a low level of adhesion of the film to the pot (no adhesive was required for the film).

[0046] Phase 4b - Positive Pressure Test vs. Hot Air Gun (150µm Film) Unfortunately, using positive pressure molding did not result in the same improvement over the hot air gun approach for the 150 μm film. The film was found to fill the cavities at a similar rate as with the hot air gun. Because the hot air approach is easier to control, the results for the 150 μm film were calculated based on the hot air gun approach.

[0047] Thermoforming optimization The progress of the tests to optimize the thermoforming conditions is detailed in Table 1 below.

[0048] [Table 1]

[0049] The final thermoforming parameters using the heat gun were detailed in Figure 5. This is considered to be the optimal cycle for uniformly forming into a container.

[0050] To calculate the liner formation rate, each liner was filled to full capacity with water and the percentage of fill weight was compared to the theoretical full weight of 28 g.

[0051] 100% molding in pot (150μm film) Thermoforming optimization defined optimal parameters for the 110 μm and 150 μm films (e.g., stretching each film to its threshold). However, testing was only able to demonstrate a maximum forming of 94%. This is likely due to a discrepancy between the specified film and the film supplied for testing.

[0052] Material analysis has determined that the thickness of the 150µm film is not 150µm, but closer to 136µm total, which means that the thermoforming results correlate as follows: 110 μm (73% of target thickness) → Maximum forming = 81% 135 μm (90% of target thickness) → Maximum forming = 94%

[0053] From these results, it is reasonable to infer the following: 150μm film → Maximum molding ≧100%

[0054] Figure 6 shows the deformation pattern of a 150 μm film (when formed "very well" in the cavity), with line spacing of approximately 5 mm. The key observation was that very little stretching was observed in the film around the cavity (due to wrinkling from the forming sequence and limitations of the test equipment) and evidence of 100% forming.

[0055] The final thermoforming parameters using the heat gun were detailed in Figure 8. This is considered to be the optimal cycle for uniformly forming into a pot.

[0056] To calculate the liner formation rate, each liner was filled to capacity with water and the percentage of fill weight was compared to the theoretical full weight of 28 g.

[0057] Example 3 Barrier Film Test 3D barrier tests were conducted using various barrier film substrates and thicknesses for water vapor transmission rate and oxygen transfer rate, and the results are shown in Figures 7 and 8, respectively.

[0058] The differences in water vapor transmission rate and oxygen transfer rate for various film thicknesses for 2D and 3D films are shown in Tables 2 and 3 below, respectively.

[0059] [Table 2]

[0060] [Table 3]

[0061] The results showed that 81% of packs were formed on the 110 μm film, whereas 94% of packs were formed on the 135 μm film.

[0062] These tests showed that the oxygen barrier achieved with the 3D geometry is very good and directly comparable to the current best-performing containers using plastic trays.

[0063] Although the water vapor transmission rate was slightly higher than the current best-performing container using plastic trays, this is within the range of the theoretical barrier and could still be gradually improved by using 150 μm film.

[0064] The formed 3D pots used in the tests were 81% formed with the 110 μm film and 94% formed with the 135 μm film, which was due to limitations in thermoforming / film elongation.

[0065] All successful tests performed to date indicate that the 150 μm films based on the modified PBS substrate are suitable for proceeding to shelf life testing studies.

[0066] Example 4 Lidding Film Test The purpose of these tests was to investigate whether certain preferred lidding films were compatible for heat sealing to the preferred modified PBS barrier films and whether the biodegradable adhesive would provide a sufficiently strong bond when activated during the thermoforming process.

[0067] The test films used in the study are detailed in Table 4 below.

[0068] [Table 4]

[0069] The test setup and parameters were as follows: test strip: 25mm x 150mm, seal temperature: 120°C (the maximum temperature that can be applied before adversely affecting the liner), seal pulse: 1 second, seal pressure: 450 lbf, test method: ASTM D1876 (T-peel), and peel speed: 300mm / min.

[0070] Figure 9 compares the peel test results with the target level of 5 N. It also shows that all values ​​are significantly lower than the defined upper limit of 10 N.

[0071] Peeled test strips were visually evaluated for failure mode as detailed in Table 5 below.

[0072] [Table 5]

[0073] The film variants with a PBS heat-seal layer consistently provided stronger adhesion to the liner film. ConD appears comparable to ConB, but the variability in results is relatively large. Therefore, due to the consistency of the results, it would be more reliable to proceed with the two PBS-based films as adhesive layers.

[0074] The peel strengths of both ConA and ConB are within the target force range.

[0075] The peel strength of Triplex Film appears to provide the greatest adhesion to the liner, as the force required for peeling causes delamination of the liner. This should be considered a "foolproof" option going forward, and may be used in tests where reliable adhesion is required, although liner peelability is not part of the evaluation criteria.

[0076] Example 5 Adhesive Test Tests were carried out to identify the best peelable adhesive to use. There are several methods for applying adhesive to pot structures, each with different levels of complexity to implement and maintain (in terms of process quality).

[0077] To determine the required benchmark force that the adhesive should target, peel tests were performed on current McCormick pots to demonstrate a peel force that was considered sufficient for consumer use. A custom test rig was created to perform this peel evaluation. Table 6 details the specifications of the variants tested and specifies the two different failure forces observed across the 10 replicates evaluated.

[0078] [Table 6]

[0079] To be conservative, testing focused on obtaining a safety factor higher than the maximum average force recorded. How this can be expressed is visualized in Figure 10, where a target value of 10-15 N was defined as the target range for liner adhesion and 5 N was defined as the lidding film adhesion. The peel speed was 120 mm / min.

[0080] Among all variants tested, the biodegradable adhesive was found to be compatible with thermoforming, Plantic / modified PBS film, and molded dry fiber tray substrates. As shown in Figure 11, liner peel testing also indicates that a dry basis weight of approximately 24 gsm provided sufficient adhesion to the liner to cause delamination of the pulp-pot inner layer. This is the maximum adhesion obtainable.

[0081] The biodegradable adhesive selected was a paper and biofilm heat seal adhesive approved for direct food contact. The recommended sealing conditions are above 100°C, 20 psi for 0.5 seconds.

[0082] The adhesive was applied to a modified PBS substrate at a dry application weight of 14 gsm, although experiments suggest that a range of 10-24 gsm is also acceptable.

[0083] The adhesive is a mixture of 3 parts 5-chloro-2-methyl-4-isothiazolin-3-one [EC No. 247-500-7] and 1 part 2-methyl-4-isothiazolin-3-one [EC No. 220-239-6] and has the following properties: Appearance: Off-white liquid Viscosity: Approximately 150 cP, Brookfield sp2, 50 rpm, 20°C Solid content: approx. 40% Specific gravity: approx. 1.05g / ml pH: 8~9 Wash: Water Shelf life: 6 months

[0084] Advantageously, the adhesive is compatible with thermoforming, modified PBS barrier liner films, and molded fiber substrates, and is compostable and food-safe.

[0085] Example 6: Alternative compostable sauce containers Figure 12 shows an alternative compostable container 10' according to the present invention. The alternative compostable container 10' is similar to the compostable container 10 shown in Figure 1 (and Figure 2). However, the container 10' does not require a compostable molded fiber tray 12; rather, the tray (and barrier film) are formed from a single material, such as a thicker barrier film, to form the barrier itself.

[0086] The container 10' is formed of a compostable molded tray 12'. The compostable molded tray 12' forms a barrier film 14'. In this example, the tray 12' is formed of the barrier film 14', and thus the tray 12' itself forms the barrier film 14'. This can also be expressed as the tray 12' providing the barrier film 14'. In the context of the alternative container 10', the barrier film 14' may be referred to as a "barrier layer 14'" and actually forms a barrier. The molded tray 12' has an outwardly extending lip 16' around the opening of the tray 12'. A compostable lid 18' is adhered to the barrier film 14' around the lip 16' by a peelable adhesive 20'. Similar to the container 10 shown in FIG. 1, the container 10' shown in FIG. 12 has an interior cavity for receiving a liquid food product 22' (e.g., tomato ketchup).

[0087] Figure 13 shows a cross section of the area designated X' in Figure 12, illustrating the layers of the various components in the lip area to which the lid 18' is adhered. In Figure 13, cross section X' of a compostable container formed from a thick, molded, compostable barrier film 14' is shown. The compostable lid 18' is adhered to the barrier film 14' by a peelable adhesive 20'. By eliminating the molded dry fiber tray component and using the barrier film to form the tray (e.g., using the same material as the barrier film), fewer parts are used, improving production efficiency and reducing manufacturing costs and time.

[0088] In the embodiment shown in Figures 12 and 13, a thick, molded, compostable barrier film 14' may be formed by laminating multiple layers or by extrusion prior to or during shaping. Preferably, the thickness of the barrier film 14' ranges from about 100 µm to about 600 µm, e.g., from about 400 µm to about 600 µm. Most preferably, the barrier film 14' has a thickness of about 400 µm and is formed of three layers, each about 130 µm thick. In embodiments, each layer is formed from a compostable bio-resin material. In certain embodiments, each layer is formed from the same modified PBS material. In other embodiments requiring a more robust barrier, an intermediate layer may include a compostable material that is an oxygen scavenger. Such an intermediate layer may include a plant by-product, such as that derived from coffee bean husks.

[0089] The manufacturing and performance parameters of the embodiment of Figures 12 and 13 can be seen from Table 7 below, which compares the embodiment to a similarly constructed container formed from a polypropylene (PP) barrier film.

[0090] [Table 7]

[0091] From Table 7 above, it can be seen that alternative containers may be formed at lower thermoforming temperatures, thereby reducing energy usage and reducing degradation of equipment used in the thermoforming process. Additionally, thermoforming at lower temperatures may facilitate faster manufacturing because heating and / or cooling times may be reduced.

[0092] Additionally, residence time is reduced compared to similar containers formed from PP barrier film, which advantageously reduces energy usage and reduces wear on manufacturing equipment.

[0093] Additionally, lower sealing temperatures may be used, which advantageously reduces energy usage and reduces wear on manufacturing equipment, which also speeds up the manufacturing process.

[0094] In particular, it can be seen from the above that WVTR is improved.

[0095] Any features described herein may be used individually or, where appropriate, in combination with one another, particularly in such combinations as are set forth in the appended claims. Any feature of each aspect or exemplary embodiment of the present invention described herein should be construed as applicable to other aspects or exemplary embodiments of the present invention, where appropriate. In other words, those skilled in the art who read this specification should consider any feature of each exemplary embodiment of the present invention to be interchangeable and combinable between different exemplary embodiments.

[0096] In connection with this application, attention is drawn to all articles and documents filed contemporaneously or prior to this application and in the public domain herewith, the contents of all such articles and documents being incorporated herein by reference.

[0097] All features disclosed in this specification (including the accompanying claims and drawings), and / or all steps of any method or process so disclosed, may be combined in any combination, except combinations in which at least some of such features and / or steps are mutually exclusive.

[0098] Each feature disclosed in this specification (including the accompanying claims and drawings), unless expressly stated otherwise, may be replaced by alternative features serving the same, equivalent or similar purpose. Thus, unless expressly stated otherwise, each feature disclosed is only an example of a generic series of equivalent or similar features.

[0099] The invention is not limited to the details of the foregoing embodiments, and extends to any novel or novel combination of features disclosed in this specification (including the accompanying claims and drawings), or any novel or novel combination of steps of the methods or processes so disclosed.

Claims

1. a) a compostable molded tray having an interior cavity for receiving a food product, an opening providing access to said food product, and a lip extending at least partially around said opening; b) the compostable molded tray forms a compostable barrier or the compostable molded tray further comprises a compostable barrier film stretched over and adhered to the interior cavity and lip of the tray by a paper and biofilm heat seal adhesive; c) a compostable lid releasably adhered around the opening and extending to the lip using a releasable adhesive; Compostable food packaging, including.

2. 10. The food package of claim 1, wherein the barrier or barrier film is formed from a compostable bio-resin material.

3. 3. The food packaging of claim 1 or 2, wherein the barrier or barrier film is formed of multiple layers.

4. 4. The food packaging of claim 1, wherein the compostable molded tray is a compostable molded fiber tray, optionally a compostable dry molded fiber tray.

5. 5. The food package of claim 1, wherein the compostable molded tray comprises a compostable barrier film stretched over and adhered to the interior cavity and lip of the tray by a paper and biofilm heat seal adhesive, the barrier film having a thickness of about 110 μm or greater.

6. 6. The food package of claim 5, wherein the barrier film has a thickness of about 135 μm or greater.

7. 7. The food package of claim 6, wherein the barrier film has a thickness of about 150 μm or more.

8. 8. The food package of claim 7, wherein the barrier film has a thickness in the range of about 150 μm to about 170 μm.

9. 9. The food package of claim 1, wherein the heat seal adhesive is applied at a dry application weight ranging from about 10 gsm to about 24 gsm.

10. 10. The food package of any one of claims 1 to 9, wherein the heat seal adhesive is applied at a dry application weight ranging from about 12 gsm to about 20 gsm.

11. 11. The food package of claim 1, wherein the heat seal adhesive is applied at a dry application weight in the range of about 14 gsm.

12. 12. The food package of claim 1, wherein the barrier or barrier film is at least partially spray coated onto or impregnated into the tray.

13. 4. The food package of claim 1, wherein the compostable molded tray forms a compostable barrier film, the thickness of the barrier film being in the range of about 400 μm to about 600 μm.

14. 14. The food package of claims 1 to 3 and 13, wherein the compostable formed tray forms a compostable barrier film, and the compostable formed tray and the compostable barrier film are integrally formed.

15. 15. The food package of any one of claims 1 to 14, wherein the lid comprises cellulose and a polymer.

16. 16. The food package of any one of claims 1 to 15, wherein the heat seal adhesive comprises a polyurethane.

17. 17. The food package of claim 16, wherein the polyurethane comprises one or more of 5-chloro-2-methyl-4-isothiazolin-3-one and / or 2-methyl-4-isothiazolin-3-one.

18. 18. The food package of any one of claims 1 to 17, further comprising a food product within the cavity.

19. 20. The food package of claim 18, wherein the food is a liquid food.

20. 20. The food package of claim 19, wherein the food product is a sauce.

21. 21. The food package of claim 20, wherein the condiment is selected from one or more of tomato ketchup, barbecue sauce, mayonnaise, mustard sauce, chili sauce, ranch dressing, curry sauce, and sweet and sour sauce.

22. 1. A method for making compostable food packaging, comprising: a) providing a compostable molded tray having an interior cavity for receiving a food product, an opening through which said food product can be accessed, and a lip extending at least partially around said opening; b) said providing said compostable molded tray forms a compostable barrier, or said method further comprises applying and / or forming and adhering a compostable barrier film over said interior cavity and lip of said tray with a paper and biofilm heat seal adhesive; c) providing a compostable lid and adhering said lid around said opening and at least a portion of said lip with a releasable adhesive; d) pressing the lid onto the opening under heated conditions and heat sealing the cavity using the lid; A method comprising:

23. 23. The method of claim 22, comprising applying and / or forming and adhering a compostable barrier film over the interior cavity and lip of the tray with a paper and biofilm heat seal adhesive, wherein the barrier film is applied to the interior cavity and lip of the tray by applying hot air to the film and negative pressure to the exterior of the tray.

24. The hot air is about 100 ｏ C ~ about 140 ｏ 24. The method of claim 23, wherein the range is C.

25. The hot air is about 100 ｏ C ~ about 110 ｏ 25. The method of claim 24, wherein the range is C.

26. 26. The method of any one of claims 23 to 25, wherein the hot air is delivered using a hot air gun.

27. 27. The method of claim 26, wherein the hot air gun is moved from a distance of about 200 mm from the barrier film to a distance of about 100 mm from the barrier film in a maximum of about 2 seconds to about 4 seconds.

28. 28. The method of claim 27, wherein the hot air gun is moved from a distance of about 190 mm from the barrier film to a distance of about 85 mm from the barrier film in a maximum of about 4 seconds.

29. 23. The method of claim 22, comprising applying and / or forming and adhering a compostable barrier film over the interior cavity and lip of the tray with a paper and biofilm heat seal adhesive, wherein the barrier film is at least partially applied to the interior cavity and lip of the tray by spray coating.

30. Step d) is about 120 ｏ 30. The method of any one of claims 22 to 29, wherein the method is carried out at about 450 lbf and / or at about 450 lbf and / or for about 1 second.

31. The providing of the compostable molded tray forms a compostable barrier, and the compostable barrier is about 100 ｏ C ~ about 170 ｏ At a temperature in the range of about 100°C, ｏ C ~ about 120 ｏ At temperatures in the range of about 105°C, most preferably ｏ C ~ about 120 ｏ The method of claim 22, wherein the thermoforming is performed in the range of C.

32. 32. The method of claim 31 , wherein the compostable barrier is thermoformed with a thermoforming residence time of less than about 1000 ms, preferably less than about 800 ms, and most preferably less than about 700 ms.

33. 33. The method of claim 22, 31 or 32, wherein step d) is formed at a temperature of less than about 200°C, preferably at a temperature of 170°C or less, most preferably in the range of about 160°C to 170°C.

34. 34. The method of claim 22 or 31-33, wherein the compostable molded tray forms a compostable barrier, and the compostable molded tray and the compostable barrier are integrally formed.

35. 35. A method according to any one of claims 22 to 34, wherein before step c), a liquid food product is placed in the cavity.

36. 36. A method according to any one of claims 22 to 35 for producing a compostable food packaging according to any one of claims 1 to 21.

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