Cellulose ester tray

Abstract

A foam tray molded from 50–99% by weight of cellulose ester. The tray includes at least one elongated reinforcing member, which is a main reinforcing member extending laterally over at least 20% of the tray's width. The main reinforcing member is positioned within 0.25 inches of the tray's lateral centerline.

Description

Background Art

[0001] Many foamed products, such as food packaging supplies, are intended to be disposable items that are discarded after use. One commercially important material used to make foamed products is polystyrene. However, polystyrene cannot be composted or biodegraded. Furthermore, some municipalities, states, and countries have implemented or are considering implementing bans on the use of polystyrene foams. Therefore, it is desirable to find alternative materials for use in foamed products, as well as promising compositions, methods, and systems for manufacturing such products.

Summary of the Invention

[0002] In one embodiment, or in combination with any other embodiment referred to herein, a foamed tray formed from 50-99 weight percent cellulose ester is provided. The tray includes at least one elongate reinforcement including a main reinforcement extending laterally across at least 20% of the width of the tray. The main reinforcement is disposed within 0.25 inches from the lateral centerline of the tray.

[0003] In another embodiment, or in combination with any other embodiment referred to herein, a process for manufacturing a foamed tray is provided. The process includes extruding a mixed composition including a cellulose ester to form a foamed sheet. The cellulose ester is included in the mixed composition in an amount of about 50 weight percent to about 99 weight percent. Additional steps include thermoforming the foamed sheet to form the foamed tray. The tray includes at least one elongate reinforcement including a main reinforcement extending laterally across at least 20% of the width of the tray. The main reinforcement is disposed within 0.25 inches from the lateral centerline of the tray.

Brief Description of the Drawings

[0004] [Figure 1] A schematic diagram showing a biodegradable product molding process according to an embodiment of the present invention. [Figure 2] This is a schematic diagram showing another biodegradable product molding process according to an embodiment of the present invention. [Figure 3] This is a schematic diagram showing an extrusion section that can be used in the article molding process of Figure 1 and / or Figure 2 according to an embodiment of the present invention. [Figure 4] This is a schematic diagram showing another extrusion section that can be used in the article molding process of Figures 1 and 2 according to embodiments of the present invention. [Figure 5] This is a schematic diagram showing a sheet molding section that can be used in the article molding process of Figure 1 and / or Figure 2 according to embodiments of the present invention. [Figure 6] This is a perspective view of a foam tray molded according to an embodiment of the present invention, the foam tray including a plurality of three laterally extending reinforcing members. [Figure 7] This is a plan view of a foam tray molded according to an embodiment of the present invention, the foam tray not containing any reinforcing material. [Figure 8] This is a perspective view of a foam tray molded according to an embodiment of the present invention, the foam tray including a plurality of five transversely extending reinforcing members. [Figure 9] This is a perspective view of a foam tray molded according to an embodiment of the present invention, the foam tray including a plurality of reinforcing members, including laterally extending reinforcing members, diagonally extending reinforcing members, and ring-shaped reinforcing members. [Figure 10] This is a perspective view of a foam tray molded according to an embodiment of the present invention, the foam tray including a plurality of four edge reinforcements. [Figure 11] This is a perspective view of a foam tray molded according to an embodiment of the present invention, the foam tray including a plurality of 10 edge reinforcement members. [Figure 12] This is a perspective view of a foam tray molded according to an embodiment of the present invention, the foam tray including a plurality of 10 edge reinforcements and corner reinforcements. [Modes for carrying out the invention]

[0005] The embodiments generally relate to methods, systems, and compositions for forming biodegradable particulate materials (e.g., pellets), foamed sheets, and articles. Figures 1 to 5 show exemplary processes including methods, systems, and compositions, which are described in further detail below.

[0006] Methods and Systems As shown in Figures 1 and 2, raw materials are introduced into a biodegradable polymer manufacturing process for producing biodegradable polymer materials. In one embodiment, or in combination with any other embodiment referred to herein, the biodegradable polymer material comprises one or more cellulose esters. The one or more cellulose esters may include cellulose acetate. In such embodiments, the raw materials may include pulp such as wood pulp and / or cotton pulp. The pulp may be dissolvable grade pulp and / or paper grade pulp. The cellulose in the pulp can be esterified, for example with acetic acid, to form biodegradable cellulose ester polymers such as cellulose acetate polymers.

[0007] Next, the biodegradable polymer material can be introduced into the compounding process. In this process, the biodegradable polymer material can be mixed with a plasticizer and optionally one or more other additives (e.g., stabilizers) to form a compound material containing a plasticized biodegradable polymer. Other additives may also be mixed with the polymer and plasticizer. For example, as shown in Figure 2, other materials (additives) may include, but are not limited to, stabilizers, physical blowing agents (multiple), chemical blowing agents (multiple) (and / or precursors), nucleating agents (multiple), surface modifying additives (multiple), pigments (multiple), fillers (multiple), and / or other additives (multiple). Mixing can be achieved by any known mixing technique, including but not limited to rolling in a cylindrical vessel, overhead stirring, sigma blade mixing, and tumbling.

[0008] The compounding process may include a particle formation process. The particle formation process may generally include mixing biodegradable polymer materials, plasticizers, and other additives to form a mixed composition, and forming particulate material from that composition. Specifically, the particle formation process may include a pelletizing process, and the particulate material may contain a number of pellets. The term “compounded CE material” means a cellulose ester material formed during the compounding process, which may include a mixture of cellulose esters, plasticizers, and other additives. Furthermore, such compounded CE material may take the form of particulate material or pellets. It should be understood that, as used herein, the terms “particle formation” or “particle formation process” may be the same as, or at least include, “pellet formation” or “pelletizing process.” In some embodiments, the particle formation process may include pelletizing in a water tank, pelletizing on an air-cooled belt, water pelletizing, solvent compounding, and the like.

[0009] In one embodiment, or in combination with any other embodiment referenced herein, plasticizers and other additives(s) may be mixed with cellulose esters by conventional melt compounding techniques. This technique involves mixing the cellulose esters with plasticizers and optionally other additives at appropriate temperatures and pressures in a twin-screw extruder equipped with appropriate mixing elements, to obtain a molten, uniformly combined cellulose ester mixture by the time the material is discharged from the extruder. The molten, compounded cellulose ester mixture may then be extruded through a die having an orifice approximately 2–6 mm in diameter to extrude strands. These strands may then be cooled with water (e.g., via underwater pelletizing) or air and cut at regular intervals to obtain uniform, desirable sizes and shapes called “pellets” or “granules.” While this specification describes a process for forming pelletized compounding materials, it will be understood that the compounding materials supplied to the foam sheet manufacturing process may be in any physical form (e.g., pellets, powders, granules, fibers) according to some embodiments. The term "compounded CE material" refers to a cellulose ester material formed during the compounding process, which may include a mixture of cellulose esters, plasticizers, and other additives. Furthermore, such compounded CE material may take the form of a molten mixture or particulate material (e.g., pellets, powders, granules, fibers, etc.).

[0010] Next, as described above, formulated CE materials containing pellets of plasticizable biodegradable polymers can be introduced into a foamed sheet manufacturing process, as shown in Figures 1 and 2. The foamed sheet manufacturing process may include one or more zones / steps for producing a foamed sheet or film, which will be described in more detail below. While exemplary foamed sheet manufacturing processes are described herein, it should be understood that certain embodiments described herein may also be applicable to rigid (i.e., non-foamed) materials and articles. As shown in Figure 1, various additives can be introduced into one or more zones of the foamed sheet manufacturing process in one embodiment or in combination with any other embodiments referred to herein. Additives may include, but are not limited to, stabilizers, physical foaming agents (or more), chemical foaming agents (or more) (and / or precursors), nucleating agents (or more), surface modifying additives (or more), pigments (or more), fillers (or more), and / or other additives (or more).

[0011] A foamed sheet manufacturing process may generally include an extrusion section and a sheet forming section. An exemplary extrusion section is shown in Figure 3. As shown, the extrusion section may include a feed preparation zone where solid additives may be combined with the compounded CE material and introduced into the downstream extrusion zone. In one embodiment, or in combination with any other embodiment referred to herein, the feed preparation zone may include a feed hopper. Thus, the compounded CE material and other solid additives may be deposited in the feed hopper, which directs the combined feed composition towards the extrusion zone. The feed preparation zone may further include a mixer where the compounded CE material and one or more additives may be mixed before being introduced into the hopper. Mixing can be achieved by any known mixing technique, including but not limited to rolling in a cylindrical vessel, overhead stirring, sigma blade mixing, and tumbling. Examples of solid additives that can be combined with the formulation materials include chemical blowing agents, nucleating agents, surface modifying additives, pigments, fillers, and / or other additives.

[0012] Next, the combined feed composition from the feed preparation zone may be introduced into the extrusion zone. The extrusion zone may generally include one or more extruders, which may include single-screw and / or twin-screw extruders. Within the extruder(s), the feed composition may be introduced into the extruder barrel and conveyed by a screw(s) through a die that forms an extruder from the feed composition. As the composition is conveyed through the extruder barrel toward the die, it may be heated and at least partially melted. Thus, the term “CE molten composition” is used herein to mean a cellulose ester-based feed composition melted into a fluid molten resin through the extrusion section. Heating may be supplied by an external heater positioned along the outside of the extruder barrel. The shape of the extruder is generally determined by the shape and size of the die head. The extruder may be further shaped by downstream processes as described below.

[0013] One or more additives can be introduced into the CE molten resin while it is in the extruder. For example, one or more physical blowing agents can be added to the CE molten resin by injecting a physical blowing agent into the composition being conveyed in the extruder barrel.

[0014] As shown in Figure 4, in one embodiment, or in combination with any other embodiment referred to herein, the extrusion zone may include a primary extrusion vessel and a cooling vessel. The primary extrusion vessel and the cooling vessel may be separate devices or may be combined as an integrated device. In any case, the supply composition from the supply preparation zone is introduced into the primary extrusion vessel and at least partially melts as it is conveyed through the extruder barrel as described above, thereby producing molten CE resin. The molten CE resin exiting the primary extrusion vessel may have a temperature of about 220°C to about 240°C. One or more additives, such as blowing agents, may be added to the molten CE resin as it is conveyed through the primary extrusion vessel.

[0015] Next, the molten CE resin from the primary extrusion vessel is introduced into a cooling vessel. The cooling vessel may be a secondary extrusion vessel that operates similarly to the primary extrusion vessel but at a lower temperature. In the cooling vessel, the molten CE resin can be further mixed to provide a substantially homogeneous mixture of the molten polymer and other additives(s). The molten CE resin can then be passed through a die and directed outward from the die head to obtain a cellulose ester-based extruder, which can be further processed in the sheet forming section of a foamed sheet manufacturing process. In one embodiment, or in combination with any other embodiment referred to herein, the molten CE resin exiting the die head may have a temperature of at least 150°C, at least 160°C, at least 170°C, at least 180°C, at least 190°C, at least 200°C, about 150°C to about 220°C, and / or about 170°C to about 200°C.

[0016] As shown in Figure 4, one or more filtration devices may be installed within the extrusion section to filter and remove particulate matter from the molten CE resin. For example, a screen changer filtration device may be installed downstream of the primary and secondary extrusion vessels, thereby removing solid components from the molten CE resin before it passes through the die head to the sheet molding section.

[0017] The sheet forming section may include any of a variety of systems and processes for forming extruded sheets from cellulose ester material that can be used for article forming. The shape of the extruded sheet is generally determined by the shape of the die head, but the shape of the sheet formed in the sheet forming section may be determined by the shape of the die head and other downstream processes. For example, the extruded sheet may generally have a flat shape, or it may be annular and subject to further processing to form a flat sheet. In embodiments where the die is annular, the die may have diameters of 1 to 40 cm, 2 to 20 cm, 2 to 10 cm, and / or 3 to 8 cm. Furthermore, the thickness of the opening from which the extruded sheet is discharged, referred to herein as the “die gap,” may generally be 0.1 to 6.0 mm, 0.1 to 3.0 mm, and / or 0.1 to 1.0 mm in size.

[0018] An exemplary sheet molding section is shown in Figure 5. As illustrated, the molten CE resin is extruded through an annular die and stretched onto a molding mandrel. A cooling fluid (e.g., air) can be flowed inside and / or outside the extruded material to cool it as it passes over the mandrel. For example, the cooling fluid can be blown from the mandrel towards the die to cool the inner surface of the extruded material between the die and the mandrel. Additionally or alternatively, the cooling fluid can be flowed across the mandrel to cool the outer surface of the extruded material as it passes over the mandrel.

[0019] A slicer (or cutting device) can be used to open up a tubular extruder, which allows the tubular shape to be formed into a flat sheet. For example, a tubular extruder passing over a mandrel may be cut open and pulled to a tension station containing one or more rollers. These rollers flatten the extruder and maintain the amount of tension required to keep the extruder pulled over the mandrel. The flattened extruder is generally in the form of a sheet, which may then be directed to a winding station, where the material may be wound for packaging and transport.

[0020] Referring again to Figures 1 and 2, the sheets produced by the sheet manufacturing process can be used to form foamed products. Foamed products will be described in more detail below. Such articles are particularly useful in the food service industry. An exemplary article is a meat tray. This article may have one or more particularly advantageous properties. For example, the article may be biodegradable and / or compostable, and / or may have excellent mechanical properties (e.g., strength, density, cell size, absorption, etc.).

[0021] composition The processes described above may include the preparation and extrusion of compositions that can be used in downstream processing to form useful articles. For example, in one embodiment, or in combination with any other embodiments referred to herein, the extrusion feed material may include particulate material comprising a biodegradable polymer, a plasticizer, and optionally one or more additives, such as those described herein. In one embodiment, or in combination with any other embodiments referred to herein, the feed material can provide a mixed composition comprising a biodegradable polymer, a plasticizer, and one or more additives, such as those described herein. In one embodiment, or in combination with any other embodiments referred to herein, the biodegradable polymer comprises a cellulose ester. Further details of composition components comprising a biodegradable polymer (e.g., a cellulose ester), a plasticizer, and other additives are shown below.

[0022] Cellulose ester The cellulose esters used as described herein may be any known in the art. Cellulose esters that can be used in the embodiments herein generally contain repeating units of the following structure:

[0023] [ka]

[0024] In the formula, R 1 , R 2 , and R 3 The substituents are independently selected from the group consisting of hydrogen, acetyl, propyl, or butyl. The substitution level of cellulose esters is usually expressed in terms of the degree of substitution ("DS"), which is the average number of non-OH substituents per anhydrous glucose unit ("AGU"). Generally, conventional cellulose contains three hydroxyl groups in each substitutable AGU unit. Therefore, DS can have values ​​from 0 to 3. Natural cellulose is a large polysaccharide with a degree of polymerization of 250 to 5,000 even after pulping and purification, and therefore the assumption that the maximum DS is 3.0 is approximately correct. Since DS is a statistical mean, a value of 1 does not guarantee that every AGU has only one substituent. In some cases, unsubstituted anhydrous glucose may exist, some with two substituents, some with three, and the value is usually a non-integer. Total DS is defined as the average number of all substituents per anhydrous glucose unit. The degree of substitution per AGU can also mean specific substituents, such as hydroxyl or acetyl. In one embodiment, or in combination with any other embodiment, n is an integer in the range of 25 to 250, or 25 to 200, or 25 to 150, or 25 to 100, or 25 to 75.

[0025] In one embodiment, or in combination with any other embodiment, a cellulose ester may have at least two anhydrous glucose rings and at least 50 to a maximum of 5,000 anhydrous glucose rings, or at least 50 to less than 150 anhydrous glucose rings. The number of anhydrous glucose units per molecule is defined as the degree of polymerization (DP) of the cellulose ester. In one embodiment, or in combination with any other embodiment, a cellulose ester may have an intrinsic viscosity (IV) of about 0.2 to about 3.0 deciliters / gram, or about 0.5 to about 1.8, or about 1 to about 1.5, measured at a temperature of 25°C for 0.25 grams of sample in 100 ml of a 60 / 40 wt solution of phenol / tetrachloroethane. In one embodiment, or in combination with any other embodiment, cellulose esters useful herein may have a DS / AGU of about 1 to about 3.0, about 2.2 to about 2.8, or 1 to less than 2.2, or 1 to less than 1.5, where the substituted ester is acetyl.

[0026] Cellulose esters can be produced by any method known in the art. An example of a cellulose ester production process is taught in Kirk-Othmer, Encyclopedia of Chemical Technology, 5th Edition, Vol. 5, Wiley-Interscience, New York (2004), pp. 394-444. Cellulose, the starting material for producing cellulose esters, can be obtained from a variety of grades and sources, including, among others, cotton linters, softwood pulp, hardwood pulp, corn fiber, and other agricultural sources, as well as bacterial cellulose.

[0027] One method for producing cellulose esters involves esterification of cellulose by mixing it with a suitable organic acid, acid anhydride, and catalyst. The cellulose is then converted to cellulose triester. Next, the cellulose triester can be hydrolyzed by adding a water-acid mixture, and then filtered to remove gel particles or fibers. Water is then added to the mixture to precipitate the cellulose ester. The cellulose ester may then be washed with water to remove reaction by-products, followed by dehydration and drying.

[0028] The hydrolyzed cellulose triesters may have three acetyl substituents. These cellulose esters can be prepared by a number of methods known to those skilled in the art. For example, cellulose esters can be prepared by heterogeneous acylation of cellulose in a mixture of carboxylic acid and anhydride in the presence of a catalyst such as H2SO4. Cellulose triesters can also be prepared by homogeneous acylation of cellulose dissolved in a suitable solvent such as LiCl / DMAc or LiCl / NMP.

[0029] Those skilled in the art will understand that the commercial term "cellulose triester" also includes cellulose esters that are not completely substituted with acyl groups. For example, cellulose triacetate commercially available from Eastman Chemical Company, Kingsport, TN, USA typically has a DS of about 2.85 to about 2.99.

[0030] After esterification of cellulose to triester, some of the acyl substituents may be removed by hydrolysis or alcohol decomposition to obtain a secondary cellulose ester. As mentioned earlier, the distribution of acyl substituents may be random or non-random depending on the specific method used. Alternatively, the secondary cellulose ester may be prepared directly without hydrolysis by using a limited amount of acylation reagent. This process is particularly useful when the reaction is carried out in a solvent that dissolves cellulose. All of these methods yield cellulose esters useful in the present invention.

[0031] In one embodiment, or in combination with any of the embodiments mentioned, the cellulose acetate is a cellulose diacetate having a polystyrene-equivalent number-average molecular weight (Mn) of about 10,000 to about 100,000, as measured by gel permeation chromatography (GPC) using NMP as the solvent and polystyrene-equivalent Mn according to ASTM D6474. In one embodiment, or in combination with any other embodiment, the cellulose acetate composition, when measured by gel permeation chromatography (GPC) according to ASTM D6474 using NMP as the solvent, has a range of 10,000 to 90,000, or 10,000 to 80,000, or 10,000 to 70,000, or 10,000 to 60,000, or less than 10,000 to 60,000, or less than 10,000 to 55,000, or 10,000 to 50,000, or less than 10,000 to 50,000, or less than 10,000 to 45,000, or 10,000 to 40,000, or 10,000 to 30,000, or 20,000. 00 to less than 60,000, or 20,000 to less than 55,000, or 20,000 to less than 50,000, or 20,000 to less than 50,000, or 20,000 to less than 45,000, or 20,000 to 40,000, or 20,000 to 35,000, or 20,000 to 30,000, or 30,000 to 60,000 It contains cellulose diacetate having a polystyrene-equivalent number-average molecular weight (Mn) of less than 00, or between 30,000 and less than 55,000, or between 30,000 and less than 50,000, or between 30,000 and less than 45,000, or between 30,000 and 40,000, or between 30,000 and 35,000.

[0032] The most common commercially available secondary cellulose esters are produced by forming cellulose triesters through the initial heterogeneous acylation of cellulose using an acid catalyst. After obtaining a homogeneous solution of the cellulose triester in the corresponding carboxylic acid, the cellulose triester is then subjected to hydrolysis until the desired degree of substitution is obtained. After isolation, random secondary cellulose esters are obtained, i.e., the relative degree of substitution (RDS) at each hydroxyl group is approximately equal.

[0033] The cellulose esters useful in the present invention can be prepared using techniques known in the art, and can also be selected from various types of cellulose esters available from, for example, Eastman Chemical Company, Kingsport, TN, USA, such as Eastman® Cellulose Acetate CA398-30 and Eastman® Cellulose Acetate CA398-10, Eastman® CAP485-20 Cellulose Acetate Propionate, and Eastman® CAB381-2 Cellulose Acetate Butyrate.

[0034] In one embodiment, or in combination with any other embodiment, cellulose esters can be prepared by converting cellulose to cellulose esters using a reactant obtained from a recycled material, such as a recycled plastic-containing synthesis gas source. In one embodiment, or in combination with any other embodiment, such reactant may be a cellulose reactant comprising an organic acid and / or acid anhydride used in a cellulose esterification or acylation reaction, such as those discussed herein.

[0035] One embodiment of the present invention provides a cellulose ester composition comprising at least one regenerated cellulose ester, or in combination with any of the embodiments described herein, wherein the cellulose ester has at least one substituent on anhydrous glucose units (AU) derived from a regenerated material (e.g., recycled plastic-containing synthesis gas).

[0036] In one embodiment, or in combination with any other embodiment, the cellulose ester composition contains 50-99% by weight, or 60-99% by weight, or 70-99% by weight, or 80-99% by weight, or 90-99% by weight, 50-90% by weight, or 60-90% by weight, or 70-90% by weight, or 80-90% by weight, or 90-99% by weight, or 50-80% by weight, or 60-80% by weight, or 70-80% by weight, or 50-70% by weight, or 60-70% by weight, or 50-60% by weight, based on the total weight of the cellulose ester composition. In some embodiments, the cellulose ester used herein may include a combination, blend, or mixture of two or more different types of cellulose esters. For example, in some embodiments, the cellulose ester used herein may consist of a blend of two or more cellulose esters having different DSACs. However, this blend may have a total DSAC of 2.2-2.8.

[0037] plasticizer In one embodiment, or in combination with any other embodiment, the cellulose ester compositions described herein may contain at least one plasticizer. The plasticizer reduces the melting temperature, i.e., Tg, and / or melt viscosity of the cellulose ester. Cellulose ester plasticizers include glycerol triacetate (triacetin), glycerol diacetate (diacetin), dibutyl terephthalate, dimethyl phthalate, diethyl phthalate, polyethylene glycol (molecular weight 200-600), dibutyl tartrate, di-2-methoxyethyl phthalate, ethyl o-benzoyl benzoate, triethylene glycol dipropionate, 1,2-epoxypropylphenylethylene glycol, 1,2-epoxypropyl (m-cresyl)ethylene glycol, 1,2-epoxypropyl (o-cresyl)ethylene glycol, β-oxyethylcyclohexene carboxylate, bis(cyclohexanate)diethylene glycol, triethyl citrate, polyethylene glycol, propylene glycol, polysorbate, sucrose octaacetate, acetylated triethyl citrate, tributyl acetyl citrate, Admex, trippropionine, Scandiflex, poloxamer copolymer, and poly Ethylene glycol succinate, diisobutyl adipate, polyvinylpyrrolidone, and glycol tribenzoate, benzoate-containing plasticizers such as the Benzoflex® plasticizer series, poly(alkyl succinates) such as poly(butyl succinate), polyethersulfone, o-cresyl p-toluenesulfonate, n-ethyltoluenesulfonamide, adipate-based plasticizers, soybean oil epoxides such as the Paraplex® plasticizer series, sucrose-based plasticizers, di Possible materials include butyl sebacate, tributylin, sucrose acetate isobutyrate, Resolflex® series plasticizers, triphenyl phosphate (TPP), triethyl phosphate (TEP), glycolates (ethylphthalyl ethyl glycolate "EPEG" and methylphthalyl ethyl glycolate "MPEG"), methoxypolyethylene glycol, 2,2,4-trimethylpentane-1,3-diirbis(2-methylpropanoate), and polycaprolactone.In some embodiments, the plasticizers used herein may include a combination or mixture of two or more different types of plasticizers.

[0038] In one embodiment, or in combination with any other embodiment, the plasticizer is a food-compatible plasticizer. Food compatibility means that it complies with applicable food additive and / or food contact regulations, and the plasticizer is permitted for use or recognized as safe by at least one (national or regional) food safety regulatory authority (or organization), for example, listed in the 21 CFR Food Additive Regulations, or otherwise recognized by the U.S. FDA with a Certificate of Gravity for Use (GRAS). In one embodiment, or in combination with any other embodiment, the food-compatible plasticizer is triacetin or polyethylene glycol (PEG) having a molecular weight of about 200 to about 600. In one embodiment, or in combination with any other embodiment, possible examples of food-compatible plasticizers include triacetin, triethyl citrate, polyethylene glycol, Benzoflex, propylene glycol, polysorbate, sucrose octaacetate, acetylated triethyl citrate, tributyl acetyl citrate, Admex, trippropionine, Scandiflex, poloxamer copolymer, polyethylene glycol succinate, diisobutyl adipate, polyvinylpyrrolidone, and glycol tribenzoate.

[0039] In one embodiment, or in combination with any other embodiment, the plasticizer may be present in an amount sufficient to enable the cellulose ester composition to be melt-processed (or thermoformed) in a conventional melt-processing apparatus to produce useful articles, such as disposable plastic products. In one embodiment, or in combination with any other embodiment, the plasticizer may be present in an amount of 1 to 40% by weight, or 5 to 25% by weight, or 10 to 25% by weight, or 12 to 20% by weight, based on the weight of the cellulose ester composition, for most thermoplastic processing. In one embodiment, or in combination with any other embodiment, profile extrusion, sheet extrusion, thermoforming, and injection molding can be achieved with plasticizer levels ranging from 10 to 30%, or 12 to 25%, or 15 to 20%, or 10 to 25% by weight, based on the weight of the cellulose ester composition.

[0040] In one embodiment or in combination with any other embodiment, the plasticizer is a biodegradable plasticizer. Some examples of biodegradable plasticizers include triacetin, triethyl citrate, acetyl triethyl citrate, polyethylene glycol, benzoic acid-containing plasticizers such as the Benzoflex® plasticizer series, poly(alkyl succinates) such as poly(butyl succinate), polyethersulfone, adipic acid-based plasticizers, soybean oil epoxides such as the Paraplex® plasticizer series, sucrose-based plasticizers, dibutyl sebacate, tributylin, plasticizers in the Resolflex® series, triphenyl phosphate, glycolic acid, polyethylene glycol, 2,2,4-trimethylpentane-1,3-diirbis(2-methylpropanoate), and polycaprolactone.

[0041] In one embodiment, or in combination with any other embodiment, the cellulose ester composition may contain a plasticizer selected from the group consisting of PEG and MPEG (methoxyPEG). The polyethylene glycol or methoxy polyethylene glycol composition has an average molecular weight of 200 to 600 daltons, and the composition is melt-workable, biodegradable, and disintegrable.

[0042] In one embodiment, or in combination with any other embodiment, the composition comprises polyethylene glycol or methoxyPEG having an average molecular weight of 300 to 550 daltons.

[0043] In one embodiment, or in combination with any other embodiment, the composition comprises polyethylene glycol having an average molecular weight of 300 to 500 daltons.

[0044] In one embodiment, or in combination with any other embodiment, the cellulose ester composition contains at least one plasticizer (as described herein) in an amount based on the total weight of the cellulose ester composition of 1-40% by weight, or 5-40% by weight, or 10-40% by weight, or 12-40% by weight, 13-40% by weight, or 15-40% by weight, or more than 15-40% by weight, or 17-40% by weight, or 20-40% by weight, or 25-40% by weight, or 5-35% by weight, or 10-35% by weight, or 13-35% by weight, or 15-35% by weight, or more than 15-35% by weight, or 17-35% by weight, or 20-35% by weight, or 5-30% by weight, or 10-30% by weight. , or containing in amounts of 13-30% by weight, or 15-30% by weight, or more than 15-30% by weight, or 17-30% by weight, or 5-25% by weight, or 10-25% by weight, or 13-25% by weight, or 15-25% by weight, or more than 15-25% by weight, or 17-25% by weight, or 5-20% by weight, or 10-20% by weight, or 13-20% by weight, or 15-20% by weight, or more than 15-20% by weight, or 17-20% by weight, or 5-17% by weight, or 10-17% by weight, or 13-17% by weight, or 15-17% by weight, or more than 15-17% by weight, or less than 5-17% by weight, or less than 10-17% by weight, or less than 13-17% by weight, or less than 15-17% by weight.

[0045] In one embodiment, or in combination with any other embodiment, at least one plasticizer includes or is a food-grade plasticizer or an FDA-approved plasticizer. The food-grade plasticizer or FDA-approved plasticizer includes or is triacetin or PEG (MW300-500).

[0046] Biodegradable polymers In one embodiment, or in combination with any other embodiment, the cellulose ester composition described herein comprises a BCE component comprising at least one biodegradable cellulose ester (BCE) which may comprise one or more of the cellulose esters described herein, and a biodegradable polymer component comprising at least one other biodegradable polymer (other than BCE). In one embodiment, or in combination with any other embodiment, the other biodegradable polymer can be selected from polyhydroxyalkanoates (PHA and PHB), polylactic acid (PLA), polycaprolactone polymer (PCL), polybutylene adipate terephthalate (PBAT), polyethylene succinate (PES), polyvinyl acetate (PVA), polybutylene succinate (PBS) and copolymers (such as polybutylene succinate-co-adipate (PBSA)), cellulose esters, cellulose ethers, starch, proteins, their derivatives, and combinations thereof. In one embodiment, or in combination with any other embodiment, the cellulose ester composition comprises two or more biodegradable polymers. In one embodiment, or in combination with any other embodiment, the cellulose ester composition contains a biodegradable polymer (other than BCE) in an amount of 0.1 to less than 50% by weight, or 1 to 40% by weight, or 1 to 30% by weight, or 1 to 25% by weight, or 1 to 20% by weight, based on the cellulose ester composition. In one embodiment, or in combination with any other embodiment, the cellulose ester composition contains a biodegradable polymer (other than BCE) in an amount of 0.1 to less than 50% by weight, or 1 to 40% by weight, or 1 to 30% by weight, or 1 to 25% by weight, or 1 to 20% by weight, based on the total amount of BCE and biodegradable polymer.In one embodiment, or in combination with any other embodiment, at least one biodegradable polymer has a weight-average molecular weight (Mw) measured by gel permeation chromatography (GPC) with methylene chloride as the solvent using a refractive index detector and a polystyrene standard, which is 10,000 to 1,000,000, or 50,000 to 1,000,000, or 100,000 to 1,000,000, or 2 The PHA comprises a range of 50,000 to 1,000,000, or 500,000 to 1,000,000, or 600,000 to 1,000,000, or 600,000 to 900,000, or 700,000 to 800,000, or 10,000 to 500,000, or 10,000 to 250,000, or 10,000 to 100,000, or 10,000 to 50,000. In one embodiment, or in combination with any other embodiment, the PHA may comprise polyhydroxybutyrate-co-hydroxyhexanoate.

[0047] Nuclear agent A nucleating agent refers to a chemical or physical material that provides sites for cell formation in a mixture of molten formulations, such as within a molten CE resin. As will be described in more detail below, nucleating agents can be added to the formulated CE material during the formulation process. Alternatively, or in addition, nucleating agents may be added during the manufacturing process of the foamed sheet. For example, a nucleating agent may be blended with the formulation introduced into the hopper of the extruder in the extrusion section. Alternatively, a nucleating agent may be added to the molten CE resin in the extruder itself. Examples of nucleating agents include physical nucleating agents and chemical nucleating agents. A physical nucleating agent is a substance that is immiscible with the polymer matrix of the molten CE resin at the extrusion temperature of the extrusion section. A chemical nucleating agent is a substance that reacts (e.g., decomposes) during extrusion (e.g., at the extrusion temperature in the extruder) to form a physical nucleating agent. Thus, a chemical nucleating agent can be considered (and referred to herein as) a precursor to a physical nucleating agent formed in situ.

[0048] Suitable physical nucleating agents include fine particles having a desired particle size and / or shape to create cell nucleation sites within the CE molten resin. For example, in some embodiments, the physical nucleating agent has an average particle size of less than 1000 microns, less than 500 microns, less than 100 microns, less than 50 microns, less than 25 microns, less than 20 microns, less than 10 microns, less than 5 microns, less than 2 microns, less than 1.5 microns, and / or less than 1.0 micron. However, in some other embodiments, it may be preferable to have nanoscale-sized particles. Furthermore, in some embodiments, the physical nucleating agent preferably has a high aspect ratio (i.e., width:height). For example, in some embodiments, the physical nucleating agent has an average aspect ratio greater than 1:1, greater than 2:1, greater than 5:1, greater than 10:1, greater than 20:1, greater than 30:1, greater than 40:1, greater than 50:1, greater than 75:1, and / or greater than 100:1. Furthermore, as described above, the physical nucleating agent must be immiscible with the polymer matrix of the CE molten resin at the extrusion temperature of the extrusion section. Therefore, in some embodiments, the physical nucleating agent needs to have a melting temperature of at least 220°C, at least 230°C, at least 240°C, at least 250°C, at least 275°C, at least 300°C, at least 325°C, or at least 350°C. However, the physical nucleating agent may be selected to have the ability to recrystallize after cooling following melting.

[0049] Examples of suitable inorganic physical nucleating agents include, but are not limited to, talc, minerals such as CaCO3 and mica, and mixtures of at least two of the above. One representative example is Heritage Plastics HT6000 linear low-density polyethylene (LLDPE) based talc concentrate. Other inorganic physical nucleating agents include wollastonite, silica, silicon dioxide, titanium dioxide, magnesium oxide, aluminum oxide and calcium silicate, barium sulfate, kaolin, aluminum trihydrate ATH (Al(OH)3), MDH (Mg(OH)2), diatomaceous earth, magnetite / hematite, halloysite, zinc oxide, and titanium dioxide. In some embodiments, the inorganic nucleating agent includes oxides such as metal oxides or mixed metal oxides, selected from one or more of the following: aluminum oxide, antimony oxide, arsenic oxide, bismuth oxide, boron oxide, calcium oxide, gallium oxide, iron oxide, lithium oxide, magnesium oxide, silicon dioxide, and titanium dioxide. In other embodiments, the inorganic nucleating agent includes silicates such as magnesium silicate and calcium silicate, selected from one or more of the following:

[0050] Biodegradable natural particulate matter derived from renewable organic sources (e.g., organic nucleating agents) has also been found to function as effective physical nucleating agents. Natural substances that can act as physical nucleating agents include substances composed of cellulose fibers and / or cellulose starch. Examples, but not limited to, include almond husk flour, animal fiber, apricot husk flour, bamboo flour, bark flour, shell flour, coconut husk flour, coconut fiber, cork flour, corn cob flour, corn cob grit, cottonseed husks, flocs and fibers, hazelnut husk flour, kenaf flour, natural fiber, nut shells and flour, oat fiber flour, olive stone flour, peanut shell flour, pecan husk flour, pine nut husk flour, pistachio nut husk flour, plant fiber, rice husk flour, rice husk grit, rice husk, soy flour, starch flour (hydrophobic), walnut husk flour, wheat husk, wheat hull, and wood flour. Other organic physical nucleating agents include cellulose powder, chitin, chitosan, metal stearate, carbon black, and dolomite.

[0051] As described above, a suitable chemical nucleating agent (or a precursor to a physical nucleating agent formed in situ) is configured to decompose when a threshold chemical reaction temperature is reached, generating cell nucleating sites in the CE molten resin. These small cells serve as nucleating sites for the proliferation of larger cells from physical or other types of blowing agents. In some embodiments, the precursor is configured to form a gas such as CO2 or N2 during the extrusion of the particulate material.

[0052] Examples of chemical nucleating agents include, but are not limited to, acids such as citric acid or citric acid-based materials. Other acids may include lauric acid, stearic acid, tartaric acid, ascorbic acid, propionic acid, and hexanoic acid. A typical example is HYDROCEROL™ CF-40E (available from Clariant Corporation), which contains citric acid and a nucleating agent. In some embodiments, the chemical nucleating agent includes a combination of acid and base, such as a carbonate, and examples of carbonates include sodium bicarbonate, zinc bicarbonate, potassium bicarbonate, sodium carbonate, and potassium carbonate. For example, a typical example of a chemical nucleating agent is a combination of citric acid and sodium bicarbonate. In some embodiments, the chemical nucleating agent may include a carrier in which the active ingredient of the nucleating agent is dispersed. For example, yet another typical example of a chemical nucleating agent is a combination of citric acid, sodium bicarbonate, and a carrier. In some embodiments, the carrier may include polystyrene. However, the carrier may include other compositions such as various biopolymers (e.g., polybutylene succinate, Capa polyester, etc.), polyolefins, and acrylic copolymers (e.g., ethylene methyl acrylate). In some such embodiments, citric acid and sodium bicarbonate may constitute about half (by weight) of the chemical nucleating agent, while the carrier constitutes the remaining half (by weight). Furthermore, in some such embodiments, there may be more sodium bicarbonate than citric acid in the chemical nucleating agent. For example, there may be about three times (by weight) more sodium bicarbonate than citric acid in the chemical nucleating agent. It should also be understood that in some embodiments, such as when the nucleating agent is hecofoam or hydrocerol, a carrier may not be required or used.

[0053] In one embodiment or in combination with any of the embodiments referenced herein, the nucleating agents are present in amounts of 0.1 to 10% by weight, 0.1 to 5.0% by weight, at least 0.1% by weight, at least 0.25% by weight, at least 0.5% by weight, at least 1.0% by weight, at least 1.25% by weight, at least 1.5% by weight, at least 1.75% by weight, at least 2.0% by weight, at least 2.25% by weight, at least 2.5% by weight, at least 2.75% by weight, or at least 3.0% by weight, or at least 3.5% by weight, or at least 4.0% by weight, or at least 4.5% by weight, and / or less than 7.5% by weight, less than 5% by weight, less than 4% by weight, less than 3% by weight, less than 2% by weight, or less than 1.0% by weight, based on the total weight of the cellulose ester composition. In some embodiments, the nucleating agents used herein may include combinations or mixtures of two or more different types of nucleating agents.

[0054] It should be noted that cellulose ester materials, whether in the form of compounded CE material or CE molten resin, can generally tolerate a maximum amount of nucleating agent that can function to form nucleating sites. Any remaining nucleating agent added to the cellulose ester material remains as a filler. Depending on the type of filler used, the filler can provide various properties to the resulting cellulose ester foam and / or article. For example, some fillers can increase / decrease the density, ductility, Young's modulus, yield strength, thermal deflection temperature, permeability, impact resistance, elongation to break, adhesive properties, and biodegradability of the cellulose ester material. Fillers can also be used to alter the visual properties (e.g., color, opacity, etc.) and tactile properties (e.g., material continuity, surface roughness, etc.) of the cellulose ester material.

[0055] foaming agent A blowing agent refers to a physical or chemical material (or combination of materials) that acts to expand nucleating sites. Blowing agents may include chemical blowing agents, physical blowing agents, combinations thereof, or several types of chemical and physical blowing agents. Blowing agents function to reduce the density of the material by expanding the cells formed in the molten mixture at the nucleating sites. Blowing agents may be added to the CE molten resin in the extruder. It has been surprisingly discovered that the hygroscopic nature of biodegradable particulate natural fillers allows them to absorb moisture, carrying the absorbed water into the molten resin mixture, where it can act as a physical blowing agent.

[0056] Examples of physical blowing agents include H2O, N2, CO2, alkanes, alkenes, ethers, ketones, argon, helium, air, or mixtures thereof. Furthermore, it has been surprisingly discovered that the hygroscopic nature of biodegradable particulate natural fillers allows them to absorb moisture, transport the absorbed water into the molten resin mixture, where it can act as a physical blowing agent. Hygroscopic and biodegradable natural fillers can be incorporated into the composition to allow them to absorb moisture before the foaming process, after which the water is released and acts as a physical blowing agent. Beneficially, water can also be used as a plasticizer for cellulose ester resins. Additionally, in some embodiments, the physical blowing agent may include hydrocarbons such as pentane / isopentane or butane / isobutane. Other hydrocarbons may include propane, ethane, methane, hexane, cyclohexane, cyclopentane, or cyclobutene.

[0057] Chemical blowing agents are materials that decompose or react to produce gases (e.g., CO2 or N2). Such gases expand cells in the molten resin mixture and / or the resulting foam mixture, creating a structural material with multiple gaseous voids that are dispersed throughout. Chemical blowing agents can be endothermic or exothermic. Chemical blowing agents typically decompose and release gases at a certain temperature. Examples of chemical blowing agents include azodicarbonamides, acids (e.g., citric acid), and carbonates (e.g., sodium bicarbonate, sodium carbonate, ammonium bicarbonate, ammonium carbonate, zinc carbonate, etc.), and combinations thereof.

[0058] In one embodiment, or in combination with any of the embodiments referenced herein, the foaming agent is present in an amount of 0.3 to 1.5% by weight, or 0.3 to 2.0% by weight, or 0.3 to 2.5% by weight, or 0.3 to 3.0% by weight, or 0.3 to 3.5% by weight, or 0.3 to 4.0% by weight, or 0.3 to 8%, or 1.3 to 1.5% by weight, or 1.3 to 2.0% by weight, based on the total weight of the cellulose ester composition. 1.3-2.5% by weight, or 1.3-3.0% by weight, or 1.3-3.5% by weight, or 1.3-4.0% by weight, or 1.3-4.5% by weight, or 1.3-5.0% by weight, or 1.3-5.5% by weight, or 1.5-3.0% by weight, or 1.5-4.0% by weight, or 1.5-5.0% by weight, or 1.5-6.0% by weight, or 2.0-3.0% by weight, or 2.0-4.0% by weight, or 2.0-5 0.0% by weight, or 2.0-6.0% by weight, or 2.5-3.0% by weight, or 2.5-4.0% by weight, or 2.5-5.0% by weight, or 2.5-6.0% by weight, or 3.0-4.0% by weight, or 3.0-5.0% by weight, or 3.0-6.0% by weight, or 0.0-9.0% by weight, or 0.5-9.0% by weight, or 1.0-9.0% by weight, or 1.5-9.0% by weight, or 2.0-9.0% by weight , or present in amounts of 2.5-9.0% by weight, or 3.0-9.0% by weight, or 3.5-9.0% by weight, or 4.0-9.0% by weight, or 4.5-9.0% by weight, or 5.0-9.0% by weight, or 5.5-9.0% by weight, or 6.0-9.0% by weight, or 6.5-9.0% by weight, or 7.0-9.0% by weight, or 7.5-9.0% by weight, or 8.0-9.0% by weight, or 8.5-9.0% by weight. In some embodiments, the blowing agent used herein may include a combination or mixture of two or more different types of blowing agents.

[0059] Surface modification additives Surface modifiers refer to materials that can be added to cellulose ester compositions to improve their processability, thereby modifying the structure of the composition (or the resulting foamed article). For example, the inventors of this application have found that adding surface modifiers to compounded CE materials (e.g., pellets in the compounding process) or CE molten resin (e.g., in the extrusion process) can improve processing by reducing undesirable adhesion of the CE molten resin to the die or mandrel (or other components in the foamed sheet manufacturing process). Such reduction in adhesion can be achieved by the surface modifier suppressing the fusion of cellulose esters caused by plasticizers. The addition of surface modifiers can also reduce blocking of cellulose ester foamed sheets produced in the sheet molding section. Furthermore, surface modifiers can also improve the foamed sheet manufacturing process by enabling the process to be carried out at lower temperatures.

[0060] Furthermore, in some embodiments, the surface modification additive may function as an antistatic additive to suppress electrical sparks or arc discharges in the molten CE resin. Suppression of electrical sparks or arc discharges can be particularly important to reduce the possibility of hydrocarbons igniting and causing a fire when hydrocarbons are used as blowing agents. Beneficially, the surface modification additive may also reduce the diffusion of blowing agents, such as hydrocarbons, from the foamed sheet or the resulting article. In some embodiments, hydrocarbons themselves can be used as surface modification additives.

[0061] Nevertheless, more common examples of surface modifiers that can be used with the compounded CE material (e.g., during the compounding process) or with the CE molten resin (e.g., during the foam sheet manufacturing process) according to embodiments of the present invention include fatty acids such as palmitic acid, tallow acid, stearic acid, oleic acid, linoleic acid and linolenic acid, arachidic acid / behenic acid, behenic acid, and erucic acid. Surface modifiers may also include fatty acid amides such as erucamide, oleoamide, stearamide, benamide, secondary amide, and bisamide.

[0062] Examples of additional surface modification additives may include glycerol esters and / or stearate esters such as monoglycerides, diglycerides, and triglycerides. Examples of monoglycerides include glycerol monostearate or monoglyceride derivatives (such as diacetyltartrate esters of mono and diglycerides (DATEM), ethoxylated monoglycerides, succinyl monoglycerides, and propylene glycol monoesters (PGME)). Examples of surface modification additives may also include metal stearate salts such as aluminum stearate, calcium stearate, lithium stearate, magnesium stearate, sodium stearate, zinc stearate, and / or combinations thereof (e.g., calcium stearate / zinc stearate). Examples of surface modifying additives include waxes such as polyolefin waxes (polypropylene wax and polyethylene wax), olefin oxide waxes, ethylene acrylic acid (EAA) copolymer waxes, ethylene methyl acrylate (EMA) copolymer waxes, EAA ionomer shafts, acrylic waxes, and / or natural waxes (such as rice bran wax, sunflower wax, sugarcane wax, candelilla wax, soybean wax, beeswax, caddelilla wax, and carnauba wax).

[0063] Other non-exclusive examples of surface modification additives include aliphatic diesters (e.g., dioctyl adipates), polyglycol diesters, alkylalkyl ether diesters, aromatic triesters, polyester resins, chlorinated hydrocarbons, halogenated hydrocarbons, alkyl ether monoesters, and alkyl monoesters. Furthermore, various oils such as aromatic oils, naphthenic oils, glyceride oils, silicone oils, and epoxidized oils (e.g., soybean oil and linseed oil) can be used as surface modification additives. Thus, in some embodiments, the surface modification additive includes plasticizers such as aliphatic diester plasticizers and polyester plasticizers. Furthermore, in some embodiments, the surface modification additive may include polyhedral oligomeric silsesquioxanes (POSS).

[0064] More generally, the surface modification additive used in the embodiments of the present invention may be less polar than the cellulose ester in the blended CE material (e.g., during the blending process) or the CE molten resin (e.g., during the foamed sheet manufacturing process). For example, the surface modification additive may have a total solubility parameter δ of less than 25 MPa, less than 20 MPa, or less than 19.5 MPa; a dispersive force solubility parameter δ of less than 18 MPa, less than 16 MPa, or less than 14 MPa; and / or a bipolar intermolecular force solubility parameter δ of less than 12 MPa, less than 8 MPa, or less than 4 MPa; and / or a hydrogen bond solubility parameter δ of less than 11 MPa, less than 10 MPa, or less than 9 MPa (based on the Hansen solubility parameter). On the other hand, in some other embodiments, the surface modification additive used in the embodiments of the present invention may be more polar than the cellulose ester in the blended CE material (e.g., during the blending process) or the CE molten resin (e.g., during the foamed sheet manufacturing process). For example, the surface modification additive may have a total solubility parameter δ of more than 21.5 MPa, more than 23 MPa, or more than 25 MPa 1 / 2 less than, 20 MPa 1 / 2 less than, or 19.5 MPa 1 / 2 less than the total solubility parameter δ; 18 MPa 1 / 2 less than, 16 MPa 1 / 2 less than, or 14 MPa 1 / 2 less than the dispersive force solubility parameter δ d ; 12 MPa 1 / 2 less than, 8 MPa 1 / 2 less than, or 4 MPa 1 / 2 less than the bipolar intermolecular force solubility parameter δ d ; and / or 11 MPa 1 / 2 less than, 10 MPa 1 / 2 less than, or 9 MPa 1 / 2 less than the hydrogen bond solubility parameter δ h may have. On the other hand, in some other embodiments, the surface modification additive used in the embodiments of the present invention may be more polar than the cellulose ester in the blended CE material (e.g., during the blending process) or the CE molten resin (e.g., during the foamed sheet manufacturing process). For example, the surface modification additive may have a total solubility parameter δ of more than 21.5 MPa, more than 23 MPa, or more than 25 MPa 1 / 2 more than, 23 MPa 1 / 2 more than, or 25 MPa 1 / 2The total solubility parameter δ may be greater than or equal to 200°C, 220°C, 240°C, 260°C, 280°C, or 300°C. Furthermore, the surface modification additive may have a molecular weight greater than 100 g / mol, 150 g / mol, 220 g / mol, 260 g / mol, 300 g / mol, or 340 g / mol, and / or less than or equal to 1000 g / mol, less than or equal to 2500 g / mol, or less than or equal to 5000 g / mol. Furthermore, it may be preferable that the surface modification additive is insoluble in the plasticizer(s) used in the cellulose ester composition. For example, it may be preferable that the surface modification additive is insoluble in triacetin. Finally, in some embodiments, the surface modification additive may be biodegradable and / or food-safe or FDA-approved.

[0065] In one embodiment, or in combination with any of the embodiments referenced herein, the surface modifiers are all present in amounts of 0.05 to 0.75% by weight, or 0.05 to 1.0% by weight, or 0.05 to 2.5% by weight, or 0.05 to 5.0% by weight, or 0.75 to 1.0% by weight, or 0.75 to 2.5% by weight, or 0.75 to 5.0% by weight, or 0.1 to 1.0% by weight, or 0.1 to 2.5% by weight, or 0.1 to 5.0% by weight, or 1.0 to 2.5% by weight, or 1.0 to 5.0% by weight, or 2.5 to 5.0% by weight, based on the total weight of the cellulose ester composition. In some embodiments, the surface modifiers used herein may include combinations or mixtures of two or more different types of surface modifiers.

[0066] Goods Extruded sheets of cellulose ester foam may be formed using the extrusion and / or sheet molding sections described above. Such extruded sheets comprise a structural material having a plurality of gas voids arranged throughout. Such gas voids are formed by the expansion of a foaming agent in the form of a gas within a cellulose polymer molten material. The structural material is cellulose ester-based, and specific amounts of the constituent components of the structural material (e.g., cellulose ester, plasticizer, nucleating agent, surface modifying additive, etc.) are described in more detail above. Articles may be molded from extruded sheets of foam according to embodiments and may be particularly useful in the food service industry. An exemplary article is a meat tray. This article may have one or more particularly advantageous properties. For example, the article may be biodegradable and / or compostable, and / or the article may have excellent mechanical properties (e.g., strength, density, cell size, absorption, etc.).

[0067] Such cellulose ester foams can be formed from cellulose ester foam sheets by thermoforming, in which heat and optionally pressure are applied to the foam sheet in a mold, producing a three-dimensional article that retains its shape even after being removed from the mold. For example, in some embodiments, the foam sheet is heated to a surface temperature 40-100°C, 50-80°C, or 50-70°C higher than the Tg of the foam sheet. In some embodiments, the Tg of the foam sheet is about 120°C. Therefore, the thermoforming process can heat the foam sheet to a surface temperature of 150-210°C or 160-200°C.

[0068] More specifically, embodiments of the present invention may include a foam tray that can be configured as a food tray for supporting one or more food items, such as meat, as shown in Figure 6. The foam tray can be formed of 50 to 99% by weight of cellulose ester. To increase the rigidity of the cellulose ester foam tray, the tray may include at least one elongated reinforcing member. The at least one reinforcing member may include a main reinforcing member "P" that extends laterally over at least 20% of the width of the tray, as shown in Figure 6. The main reinforcing member P may be positioned within 0.25 inches from the lateral centerline "Y" of the tray. In other embodiments, the main reinforcing member P may be positioned within 0.20 inches, 0.15 inches, 0.10 inches, and / or 0.05 inches from the lateral centerline Y of the tray. In yet another embodiment, the main reinforcing member P may coincide approximately with the lateral centerline Y of the tray.

[0069] The foam trays molded according to embodiments of the present invention can be molded to various sizes. For example, as shown in Figure 7, the tray may have a width "W" ranging from 2 to 12 inches, 3 to 10 inches, or 5 to 9 inches, and a length "L" ranging from 4 to 24 inches, 5 to 18 inches, or 6 to 15 inches. Thus, in some embodiments, the length of the tray may be 1.2 to 4 times, 1.4 to 3 times, or 1.5 to 2 times the width of the tray.

[0070] As shown in Figures 6 and 7, the foam tray may comprise a substantially flat base and a rim that rises above the base and extends around the perimeter of the foam tray. In some embodiments, the substantially flat portion of the base constitutes 40–95%, 50–90%, or 60–85% of the total area of ​​the base. The top surface of the base and the surrounding rim define a receiving area (e.g., a bowl) that can hold and support articles (e.g., meat, cheese, vegetables, fruit, or other foods). In some embodiments, the receiving area may be divided into one or more different sections or compartments (e.g., via reinforcing materials or other surface contours) so that individual food pieces (or multiple food pieces) can be supported within each compartment. In any case, the area of ​​the base can be 5–100 square inches, 10–75 square inches, or 20–50 square inches. The rim height (measured from the bottom of the tray to the top of the rim) can be 0.2–4 inches, 0.4–2 inches, or 0.5–1 inch, and the rim width (i.e., the lateral or longitudinal distance "Rw" measured from the side or edge of the tray to the point where the rim contacts the base, as shown in Figure 7) can be 0.06–0.75 inches, 0.10–0.50 inches, or 0.25–0.50 inches. Alternatively, the rim width "Rw" may be approximately 0.01W–0.1W, or approximately 0.03W–0.06W, where "W" is the width of the tray, as described above. The ratio of the base area to the rim area can be 1–10, 1.5–6, or 2–4. Furthermore, the tray depth (measured from the top surface of the rim to the top surface of the base) may be 0.3–4 inches, 0.5–3 inches, 1–3 inches, 1–2 inches, 1.25–2 inches, approximately 1.25 inches, or approximately 1.5 inches. Furthermore, the tray thickness (i.e., the thickness of the cellulose ester foam material) may be 1–10 mm, 1–8 mm, 2–8 mm, 3–7 mm, 4–6 mm, approximately 4 mm, approximately 5 mm, or approximately 6 mm, and / or less than 5 mm, less than 4 mm, less than 3 mm, or less than 2 mm. Alternatively or additionally, the tray or other articles may have a thickness of 100–400 mils, 120–300 mils, or 150–250 mils (i.e., the thickness of the cellulose ester foam material).

[0071] With regard to reinforcement, as described above, the foam tray is molded to include at least one transversely extending reinforcement P positioned within 0.25 inches (longitudinally) from the transverse centerline Y of the tray. However, additional embodiments may provide that the tray includes multiple reinforcements. For example, the tray may include at least three reinforcements, including a main reinforcement P, a first auxiliary reinforcement "S1", and a second auxiliary reinforcement "S2", each of which is shown in Figure 6. As shown, the first and second auxiliary reinforcements S1 and S2 are positioned on both sides longitudinally of the main reinforcement P. Thus, the reinforcements P, S1, and S2 extend substantially parallel to each other. As will be described in more detail below, the tray may include other numbers of reinforcements, such as five, seven, or more.

[0072] The reinforcing material may include raised ribs or other structures extending from the outer surface of the tray base. For example, the reinforcing material may extend above the top surface of the tray base and / or below the bottom surface of the tray base. The reinforcing material may extend above or below the surface of the tray base by 2–10 mm, 3–8 mm, or 4–7 mm. Nevertheless, in some embodiments, the reinforcing material is molded integrally with the rest of the tray.

[0073] In some embodiments, the reinforcing members may be spaced 16–64 mm, 24–38 mm, or about 32 mm apart from each other. Alternatively, if the foam tray may have a length L, the reinforcing members may be spaced 0.02 L–0.20 L, 0.5 L–0.15 L, or about 0.10 L apart from each other. While the reinforcing members described above (and the reinforcing members shown in Figure 6) are shown extending laterally, it should be understood that the tray may include one or more elongated reinforcing members extending in other directions, such as longitudinal, diagonal, or annular. In some embodiments, the laterally extending reinforcing members may extend over at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, or 75% of the tray's width, and / or over as much as 100%, 95%, 90%, 80%, 70%, 60%, or 50% of the tray's width. In other embodiments, the reinforcing material may extend over 50–100%, 60–95%, or 70–90% of the tray's width. Thus, in some embodiments, the reinforcing material may extend across the width of the tray (e.g., along the base) without contacting the rim. However, in some other embodiments, the reinforcing material may contact the rim or form part of the rim to interconnect the base and the rim.

[0074] In some embodiments, the reinforcing material may be molded within the range of at least a portion of the tray rim, so that the rim includes a portion of the reinforcing material. As a result, the reinforcing material may extend substantially (or entirely) across the width of the tray. In some embodiments, the reinforcing material may be molded using molding protrusions positioned inside (or forming part of) a thermoforming die used to thermoform a foam sheet into a foam tray. Specifically, the molding protrusions may include elongated projections and / or arched projections positioned within the bottom of the die. Thus, the projections extend upward and / or inward from the molding surface of the thermoforming die. When the foam sheet is placed inside the thermoforming die, the molding protrusions push the foam of the foam sheet upward and / or inward at the position of the molding protrusions. As a result, the reinforcing material is molded from the foam material of the base and / or rim portion of the tray.

[0075] In such embodiments, the reinforcing material may be formed (by a molded projection) as an elongated recess extending upward from the bottom surface of the tray base. Similarly, the reinforcing material may be formed (by a molded projection) as an elongated recess extending inward from the outer surface of the tray rim. Similarly, the reinforcing material may be formed (by a molded projection) as an elongated projection extending upward from the top surface of the tray base. Similarly, the reinforcing material may be formed (by a molded projection) as an elongated projection extending inward from the inner surface of the tray rim.

[0076] As mentioned above, the reinforcing material may extend across the entire width of the tray. Furthermore, the reinforcing material may have a thickness of 1 / 16 to 1 / 2 inch, 1 / 8 to 1 / 4 inch, or about 1 / 8 inch or about 1 / 4 inch (measured, for example, from the top surface of the tray base to the top surface of the reinforcing material). Furthermore, the width of the reinforcing material may be 1 / 16 to 1 / 2 inch, 1 / 8 to 1 / 4 inch, or about 1 / 8 inch or about 1 / 4 inch (measured, for example, in the longitudinal direction of Figure 6). The size of the reinforcing material (e.g., thickness and / or width) may be determined by the size of the molded protrusions used during thermoforming.

[0077] Figure 6 shows a foam tray having three elongated reinforcing members, but embodiments of the present invention provide foam trays with various numbers of reinforcing members. For example, Figure 8 shows an embodiment of a tray having five reinforcing members. Other numbers of trays are also envisioned, such as a tray having one reinforcing member that generally extends along the transverse centerline of the tray. Furthermore, trays with seven, nine, or more reinforcing members are also envisioned. Regardless of the number of reinforcing members included in the tray, some embodiments provide at least one reinforcing member (e.g., a main reinforcing member) that extends roughly along (or within 0.25 inches of) the transverse centerline of the tray. The remaining reinforcing members (e.g., secondary reinforcing members) may be positioned on either side of the main reinforcing member (e.g., spaced longitudinally in the tray of Figure 8).

[0078] Other foam trays with reinforcing members are also conceivable. For example, Figure 9 shows a foam tray with annular reinforcing members. Specifically, the tray in Figure 9 includes a main reinforcing member that extends roughly along the lateral centerline of the tray. In some embodiments, the main reinforcing member may extend along the entire width of the tray, resulting in the main reinforcing member extending at least partially through the rim of the tray. In other embodiments, the main reinforcing member may extend only along the base of the tray. In any case, the tray may also include a pair of oblique reinforcing members that extend roughly obliquely across the tray from opposing corners of the tray. In some embodiments, the oblique reinforcing members may extend along the entire diagonal distance of the tray, resulting in the oblique reinforcing members extending at least partially through the rim of the tray. In other embodiments, the oblique reinforcing members may extend only along the diagonal length of the base of the tray.

[0079] The tray also includes multiple ring-shaped concentric reinforcements. Such ring-shaped reinforcements may include inner ring-shaped reinforcements whose centers coincide with the centers of the tray's base. The diameter of the inner ring-shaped reinforcements may be 10–40% of the tray's width, 20–30% of the tray's width, at least 20% of the tray's width, or about 25% of the tray's width. The ring-shaped reinforcements may also include a central ring-shaped reinforcement whose center coincides with the centers of the tray's base. The central ring-shaped reinforcement may have a diameter approximately equal to the width of the tray's base. Thus, the central ring-shaped reinforcement is positioned around the inner ring-shaped reinforcements. Finally, the ring-shaped reinforcements may also include outer ring-shaped reinforcements whose centers coincide with the centers of the tray's base. The outer ring-shaped reinforcement may have a diameter greater than the width of the tray's base, so that only the arched portion of the outer ring-shaped reinforcement is present on the tray. Nevertheless, the outer ring-shaped reinforcement is positioned around the central and inner ring-shaped reinforcements.

[0080] Figure 10 shows another embodiment of a foam tray with reinforcement. Such reinforcement extends inward from the rim of the tray and is therefore sometimes referred to as rim reinforcement. More specifically, the tray includes a pair of reinforcement members that extend inward toward each other in a lateral direction from both sides of the rim toward the center of the base of the tray. Laterally extending reinforcement members may generally extend along the lateral centerline of the tray. However, laterally extending reinforcement members do not extend across the entire width of the base of the tray and therefore there are empty areas (i.e., areas without reinforcement) within the central portion of the base of the tray. In some embodiments, each laterally extending reinforcement member may extend over 10–40% of the tray width, 20–30% of the tray width, at least 20% of the tray width, or about 25% of the tray width. In some embodiments, the laterally extending reinforcement members may extend only along the base of the tray, or they may extend along both the base and the rim of the tray. The tray in Figure 10 may also include a pair of reinforcing members that extend longitudinally from both ends of the rim toward the center of the tray base, and inward toward each other. The longitudinally extending reinforcing members can generally extend along the longitudinal centerline of the tray. However, the longitudinally extending reinforcing members do not extend over the entire length of the tray base, and therefore there are empty areas (i.e., areas without reinforcing members) within the central portion of the tray base. In some embodiments, each longitudinally extending reinforcing member may have a length of 10–40% of the tray width, 20–30% of the tray width, at least 20% of the tray width, or about 25% of the tray width. In some embodiments, the longitudinally extending reinforcing members may extend only along the tray base, or they may extend along both the tray base and the rim.

[0081] Figure 11 shows an additional embodiment of a tray with edge reinforcement, the tray of Figure 11 being similar to the tray shown in Figure 10. However, the tray of Figure 11 includes additional transversely extending reinforcement extending from the sides of the tray. Specifically, each side of the tray may include two additional transversely extending reinforcement extending (longitudinally) on either side of a centrally located transversely extending reinforcement (i.e., coinciding with the transverse centerline of the tray). Each of the two additional transversely extending reinforcements positioned on a given side of the tray may be positioned within 1 / 2 inch, 1 / 4 inch, or 1 / 8 inch from the centrally located transversely extending reinforcement. The remaining properties of the transversely extending reinforcement (e.g., length) may be the same as the corresponding properties of the transversely extending reinforcement in Figure 10. Furthermore, each end of the tray in Figure 11 may include a pair of longitudinally extending reinforcement. Such longitudinally extending reinforcements may not coincide with the longitudinal centerline of the tray, but may be at least partially offset from the longitudinal centerline. For example, longitudinally extending reinforcements may be offset within 1 / 2 inch, 1 / 4 inch, or 1 / 8 inch from the longitudinal centerline. Furthermore, each of the additional longitudinally extending reinforcements at a given end of the tray may be positioned within 1 / 2 inch, 1 / 4 inch, or 1 / 8 inch of each other. The remaining properties of the longitudinally extending reinforcements (e.g., length) may be the same as the corresponding properties of the longitudinally extending reinforcements in Figure 10.

[0082] Finally, Figure 12 shows a foam tray with an additional configuration of reinforcing members. The tray in Figure 12 may include a pair of longitudinally extending reinforcing members substantially identical to those described for the tray in Figure 10. The tray in Figure 12 may also include four obliquely extending reinforcing members, each extending diagonally inward from one of the corners of the tray toward the center of the tray base. Such obliquely extending reinforcing members are sometimes called corner reinforcing members. The obliquely extending reinforcing members do not extend across the entire base of the tray, and therefore there are empty areas (i.e., areas without reinforcing members) within the central portion of the base of the tray. In some embodiments, each obliquely extending reinforcing member may have a length spanning 10–40% of the tray width, 20–30% of the tray width, at least 20% of the tray width, or about 25% of the tray width. In some embodiments, the obliquely extending reinforcing members may extend only along the base of the tray, or they may extend along both the base and the rim of the tray. Furthermore, each side of the tray in Figure 12 may include a pair of laterally extending reinforcing members. Such laterally extending reinforcing members may not coincide with the laterally extending centerline of the tray, but may be at least partially offset from the laterally extending centerline. For example, the laterally extending reinforcing members may be offset within 1 / 2 inch, 1 / 4 inch, or 1 / 8 inch from the laterally extending centerline. In addition, each of the laterally extending reinforcing members at a given end of the tray may be positioned within 1 / 2 inch, 1 / 4 inch, or 1 / 8 inch of each other. The remaining properties of the laterally extending reinforcing members (e.g., length) may be the same as the corresponding properties of the laterally extending reinforcing members in Figure 10.

[0083] Embodiments provide the foam tray described herein, molded according to the process described herein. Specifically, a mixed composition containing cellulose ester (e.g., present in an amount of about 50% to about 99% by weight) can be extruded through an extruder to form a cellulose ester foam sheet. The foam sheet can then be thermoformed to form a tray, which may include a base, a rim, and at least one reinforcing member. Thus, each of the base, rim, and reinforcing member may be molded from a single sheet of cellulose ester foam. The resulting foam tray can be used to support food such as meat. Thus, in some embodiments, an absorbent pad is placed on top of the base in the receiving area so that liquid from the meat (or other food) can be absorbed by the pad. Furthermore, a shrink film can be wrapped around the tray to securely hold the meat in it and protect it from the environment. Beneficially, the reinforcing member provides additional rigidity to the tray so that it does not bend excessively or break under the force applied by the shrink film. For example, the reinforcing material can provide additional rigidity and support to the shrink film that exerts force on at least two sides and / or at least four sides of the tray. Such force from the shrink film may be a compressive force of at least 0.1 MPa, 0.5 MPa, or 4 MPa. In other embodiments, the foam tray may be configured to be wrapped with an overlapping film that covers and protects the tray and the food inside the tray without applying a considerably large pressure and / or force to the tray.

[0084] In one embodiment, or in combination with any of the embodiments referenced herein, the foamed product, for example, the tray, is 0.20 g / cm³. 3 Less than 0.18 g / cm³ 3 Less than 0.15 g / cm³ 3 Less than 0.12 g / cm³ 3 Less than 0.10 g / cm³ 3 Less than 0.08 g / cm³ 3 Less than 0.06 g / cm³ 3 Less than 0.04 g / cm³ 3 Less than 0.04-0.8 g / cm³3 、0.04~0.6g / cm 3 、0.04~0.5g / cm 3 、0.04~0.4g / cm 3 、0.04~0.3g / cm 3 、0.04~0.2g / cm 3 、0.04~0.15g / cm 3 、0.04~0.12g / cm 3 、0.04~0.10g / cm 3 、0.04~0.08g / cm 3 、0.04~0.06g / cm 3 、0.06~0.8g / cm 3 、0.06~0.6g / cm 3 、0.06~0.5g / cm 3 、0.06~0.4g / cm 3 、0.06~0.3g / cm 3 、0.06~0.2g / cm 3 、0.06~0.15g / cm 3 、0.06~0.12g / cm 3 、0.06~0.10g / cm 3 、0.06~0.08g / cm 3 、0.08~0.8g / cm 3 、0.08~0.6g / cm 3 、0.08~0.5g / cm 3 、0.08~0.4g / cm 3 、0.08~0.3g / cm 3 、0.08~0.2g / cm 3 、0.08~0.15g / cm 3 、0.08~0.12g / cm 3 、0.08~0.10g / cm 3 、0.1~0.8g / cm 3 、0.1~0.6g / cm 3 、0.1~0.5g / cm 3 、0.1~0.4g / cm 3 、0.1~0.3g / cm 3 、0.1~0.2g / cm 3 、0.1~0.15g / cm 3 、0.1~0.12g / cm 3 、0.2~0.8g / cm3 , 0.2~0.6 g / cm³ 3 , 0.2~0.5 g / cm³ 3 , 0.2~0.4 g / cm³ 3 , 0.2~0.3 g / cm³ 3 , 0.3~0.6 g / cm³ 3 , 0.3~0.5 g / cm 3 , 0.3~0.4 g / cm³ 3 , 0.4~0.6 g / cm³ 3 , 0.4~0.5 g / cm 3 , or 0.5~0.6 g / cm³ 3 It may have a density of .

[0085] In one embodiment, or in combination with any of the embodiments referenced herein, the average foam cell size is 40 μm to 600 μm, or 50 μm to 600 μm, or 60 μm to 600 μm, or 70 μm to 600 μm, or 80 μm to 600 μm, or 90 μm to 600 μm, or 100 μm to 600 μm, or 150 μm to 600 μm, or 200 μm to 600 μm, or 250 μm to 600 μm. , or 300μm~600μm, or 400μm~600μm, or 500μm~600μm, or 40μm~550μm, or 40μm~500μm, or 40μm~450μm, or 40μm~400μm, or 40μm~350μm, or 40μm~300μm, or 40μm~250μm, or 40μm~200μm, or 40μm~150μm, or 40μm~100μm.

[0086] Furthermore, since foamed products, such as trays, are molded from the cellulose esters described herein, it should be understood that foamed products may contain any components and / or additives of the cellulose ester-based materials described herein, as well as any resulting properties. [Examples]

[0087] The following embodiments demonstrate how foam trays molded according to embodiments of the present invention may include beneficial mechanical properties, such as improved strength characteristics. Each of the following embodiments was obtained by performing tray stiffness tests using a force tester that included a Ryback & Ryback electric test stand equipped with a Mark-10 Series 5 Model M5-50 force gauge connected to MeasurGauge Plus software. In the tray stiffness test, the tray was compressed laterally to measure the "edge-to-edge stiffness of the side" of the tray. Such edge-to-edge stiffness of the side is a useful property for measuring the ability of the tray to withstand deformation when food is placed in the tray and then wrapped in plastic film.

[0088] The tray rigidity test was performed as follows: Each tray under test was oriented laterally, with one side of the tray configured as the bottom side, positioned within an elongated rail guide fixed to the bottom of the test stand. The opposite side was configured as an open top surface to engage with an elongated contact element fixed to the working ram of the test stand. The contact element had a length of approximately 3 / 4 of the length of the top side of the tray, and its center was approximately coincident with the lateral centerline of the tray. Next, the working ram of the test stand was moved vertically downward, applying force to the side of the tray.

[0089] The stiffness of a tray is based on Hooke's Law (i.e., F = kΔL), where the deformation of the tray (ΔL) is caused by a force (F). The proportionality constant (k) is determined by the shape and composition of the tray, as well as the direction of the force. Therefore, Hooke's Law stipulates that the slope of the straight section (proportionality constant k) of the curve F = kΔL is expressed as the stiffness. Thus, the stiffness (k) of the tray can be measured in MeasurGauge Plus software using the force value (F) obtained by the force gauge when the test stand moves vertically downward, generating the deformation of the tray (ΔL).

[0090] To obtain the stiffness value according to the tray stiffness test, the contact element of the test stand was first moved 0.5 inches downward by the ram, and then initially made contact with the upper side of the tray. After such an initial movement of 0.25 inches, the MeasurGague Plus software was zeroed. Subsequently, the contact element of the test stand was moved vertically downward by the ram at a speed of 0.8333 mm / sec, and the total test time was 30 seconds. The MeasurGague Plus software began reading data when it made contact with the upper side of the tray. The MeasurGaguePlus software performed 50 data readings of force (F) and deformation (ΔL) during the test, resulting in an interval of 0.0167 mm between data readings and a time interval of 0.0240 seconds between data readings. The total distance the test stand moved was 25 mm, and the total number of data readings was 1500.

[0091] Example A Seven foam trays were thermoformed from a foam sheet using a Hydrotrim Lab thermoformer. The thermoformer had a mold with upper and lower heating plates inside the oven. A timer was used to set the holding time inside the oven. Vacuum was used to draw the material into the mold, and plug assist was used for complex parts. The trays evaluated for this study were fabricated using vacuum alone, with the upper and lower plates heated to 260°C. The foam sheet was heated for 35 seconds to generate a sheet temperature of 182–188°C.

[0092] The foamed sheets contained cellulose acetate (Ds2.5) with 20% triacetin as a plasticizer and less than 2% stabilizers and colorants. The foamed sheets were molded using 1% Foamazol73S chemical blowing agent and 1% ABT1000 talc as a nucleating agent. The foamed sheets were also prepared using 2.6% pentane as the main blowing agent. The melting temperature of the primary extruder was 210°C, and the melting temperature of the secondary extruder was 187°C. The foamed sheets were prepared at a die pressure of 33 bar. The density of the foamed sheets was 0.095 g / cc, the sheet thickness was 4 mm, and the average cell size was 340 microns.

[0093] The density of the foam trays decreased to 0.072 g / cc during thermoforming. The resulting foam trays were 8.6 inches long, 6.5 inches wide, and 1.25 inches high (measured from the bottom surface of the tray base to the top surface of the tray rim).

[0094] As shown in Table 1 below, seven foam trays were molded using the method described above and tested using a tray stiffness test. The first tray, EX-1, is a control tray formed without reinforcement and is therefore configured similarly to the tray shown in Figure 7. The second tray, EX-2, and the fifth tray, EX-5, are each formed with a single reinforcement extending along the lateral centerline of the tray and across the entire base of the tray, which also forms part of the tray's lip. The third and sixth trays, EX-3 and EX-6, are each formed with three reinforcements. Specifically, the third and sixth trays, EX-3 and EX-6, are configured similarly to the tray shown in Figure 6. The fourth and seventh trays, EX-4 and EX-7, are each formed with five reinforcements. Specifically, the fourth and seventh trays, EX-4 and EX-7, are configured similarly to the tray shown in Figure 8. The height of the reinforcing material in the second tray EX-2, the third tray EX-3, and the fourth tray EX-4 (measured from the top surface of the tray base to the top surface of the reinforcing material) was approximately 1 / 4 inch, which was relatively higher than the height of the reinforcing material in the fifth tray EX-5, the sixth tray EX-6, and the seventh tray EX-7 (measured from the top surface of the tray base to the top surface of the reinforcing material), which was approximately 1 / 8 inch.

[0095] [Table 1]

[0096] As shown in Table 1, the third tray EX-3 and the fourth tray EX-4, formed with three and five reinforcing members respectively, were found to have improved rigidity compared to the control tray EX-1. All other trays showed no improvement and were instead less rigid than the control tray EX-1. The height of the reinforcing members in the third tray EX-3 and the fourth tray EX-4 (i.e., 1 / 4 inch) was found to be relatively higher than the height of the reinforcing members in the remaining trays EX-5, EX-6, and EX-7 (i.e., 1 / 8 inch).

[0097] Example B Three foam trays were thermoformed from a foam sheet using a Hydrotrim Lab thermoformer. The thermoformer had a mold with upper and lower heating plates inside the oven. A timer was used to set the holding time inside the oven. Vacuum was used to draw the material into the mold, and plug assist was used for complex parts. The trays evaluated for this study were fabricated using vacuum alone, with the upper and lower plates heated to 260°C. The foam sheet was heated for 35 seconds to generate a sheet temperature of 182–188°C.

[0098] The foamed sheets contained cellulose acetate (Ds2.5) with 20% triacetin as a plasticizer and less than 2% stabilizers and colorants. The foamed sheets were molded using 1% Foamazol 73S chemical blowing agent and 1% ABT1000 talc as a nucleating agent. The foamed sheets were also prepared using 2.5% pentane as the main blowing agent. The melting temperature of the primary extruder was 210°C, and the melting temperature of the secondary extruder was 187°C. The foamed sheets were prepared at a die pressure of 40 bar. The density of the foamed sheets was 0.109 g / cc, the sheet thickness was 5 mm, and the average cell size was 702 microns.

[0099] Each of the resulting foam trays measured 8.6 inches in length, 6.5 inches in width, and 1.25 inches in height (measured from the bottom surface of the tray base to the top surface of the tray rim). Three foam trays were molded using the method described above and tested using a tray stiffness test, as shown in Table 2 below.

[0100] The first tray, EX-8, is a control tray formed without any reinforcing materials and is therefore configured similarly to the tray shown in Figure 7. The second tray, EX-9, is configured similarly to the tray shown in Figure 9 and includes multiple reinforcing materials, including laterally extending reinforcing materials, diagonally extending reinforcing materials, and ring-shaped reinforcing materials. The third tray, EX-10, is formed with multiple laterally extending reinforcing materials and longitudinally extending reinforcing materials (i.e., a total of 10 edge reinforcing materials). Specifically, the third tray, EX-10, is configured similarly to the tray shown in Figure 11.

[0101] [Table 2]

[0102] As shown in Table 2, both the second tray EX-9 and the third tray EX-10 showed a significant improvement in stiffness compared to the control tray EX-8. Specifically, the second tray EX-9, which has ring-shaped reinforcements, showed a 35% increase in stiffness, and the third tray EX-10, which has multiple edge reinforcements, showed a 45% increase in stiffness.

[0103] Example C Four foam trays were thermoformed from a foam sheet using a Hydrotrim Lab thermoformer. The thermoformer features a mold with upper and lower heating plates inside the oven. A timer was used to set the holding time inside the oven. Vacuum was used to draw the material into the mold, and plug assist was used for complex parts. The trays evaluated for this study were fabricated using vacuum alone, with the upper and lower plates heated to 260°C. The foam sheet was heated for 35 seconds to generate a sheet temperature of 190–196°C.

[0104] The foamed sheets contained cellulose acetate (Ds2.5) with 20% triacetin as a plasticizer and less than 2% stabilizers and colorants. The foamed sheets were molded using 1% Foamazol73S chemical blowing agent and 1% ABT1000 talc as a nucleating agent. The foamed sheets were also prepared using 2.3% pentane as the main blowing agent. The melting temperature of the primary extruder was 210°C, and the melting temperature of the secondary extruder was 187°C.

[0105] Each of the resulting foam trays measured 8.6 inches in length, 6.5 inches in width, and 1.25 inches in height (measured from the bottom surface of the tray base to the top surface of the tray rim). As shown in Table 3 below, four foam trays were molded using the method described above and tested using a tray stiffness test.

[0106] The first tray EX-11 and the third tray EX-13 are control trays formed without any reinforcing materials, and are therefore configured similarly to the trays shown in Figure 7. The second tray EX-12 and the fourth tray EX-14 have multiple laterally extending reinforcing materials and vertically extending reinforcing materials (i.e., a total of 10 edge reinforcing materials). Specifically, the second tray EX-12 and the fourth tray EX-14 are configured similarly to the trays shown in Figure 11.

[0107] Notably, the first tray EX-11 and the second tray EX-12 were molded from a foam with an average cell size of 295 microns and a foam density of 0.108 g / cc. These cell sizes were achieved by molding the foam sheets at a die pressure of 32 bar. In contrast, the third and fourth trays EX-13 and EX-14 were formed from foam sheets with an average cell size of 148 microns and a foam density of 0.103 g / cc. These cell sizes were achieved by forming the corresponding foam sheets using a die pressure of 70 bar.

[0108] [Table 3]

[0109] As shown in Table 3 above, each tray formed with reinforcing material showed a significant increase in rigidity compared to the control tray. Specifically, the second tray EX-12 showed an 89% increase in rigidity compared to the control tray EX-11. Similarly, the fourth tray EX-14 showed a 99% increase in rigidity compared to the control tray EX-13. Furthermore, trays formed with smaller cell sizes showed increased rigidity compared to the corresponding trays formed with larger cell sizes. Specifically, the third tray EX-13, which was the control tray, showed a 9% increase in rigidity compared to the first tray EX-11, which was also the control tray. Similarly, the fourth tray EX-14, formed with reinforcing material, showed a 15% increase in rigidity compared to the second tray EX-12, which was also formed with reinforcing material.

[0110] Example D Eight foam trays were thermoformed from a foam sheet using a Hydrotrim Lab thermoformer. The thermoformer had a mold with upper and lower heating plates inside the oven. A timer was used to set the holding time inside the oven. Vacuum was used to draw the material into the mold, and plug assist was used for complex parts. The trays evaluated for this study were fabricated using vacuum alone, with the upper and lower plates heated to 260°C. The foam sheet was heated for 35 seconds to generate a sheet temperature of 182–188°C.

[0111] The foamed sheets contained cellulose acetate (Ds2.5) with 15% or 20% triacetin as a plasticizer (see Table 4 below), and less than 2% stabilizers and colorants. The foamed sheets were molded using 1% Foamazol 73S chemical blowing agent and 1% ABT1000 talc as a nucleating agent. The foamed sheets were also prepared using 2.5% pentane as the main blowing agent. The melting temperature of the primary extruder was 210°C to 220°C, and the melting temperature of the secondary extruder was 180°C to 200°C. The foamed sheets were prepared at a die pressure of 30 to 50 bar.

[0112] Each of the resulting foam trays measured 8.6 inches in length, 6.5 inches in width, and 1.25 inches in height (measured from the bottom surface of the tray base to the top surface of the tray rim). Eight foam trays were molded using the method described above and tested using a tray stiffness test, as shown in Table 4 below. Note that the first five trays (i.e., EX-15 to EX-19) had a thickness of 5 mm and contained 20% plasticizer, while the last three trays (i.e., EX-20 to EX-22) had a thickness of 4 mm and contained 15% plasticizer.

[0113] The first tray, EX-15, was a control tray formed without any reinforcing materials and was therefore constructed similarly to the tray shown in Figure 7. The second tray, EX-16, was constructed using multiple lateral and longitudinal reinforcing materials (i.e., a total of four edge reinforcing materials). Specifically, the second tray, EX-16, was constructed similarly to the tray shown in Figure 10. The third tray, EX-17, was also constructed using multiple lateral and longitudinal reinforcing materials (i.e., a total of four edge reinforcing materials). Specifically, the third tray, EX-17, was also constructed similarly to the tray shown in Figure 10. In contrast, the height of the reinforcing materials on the second tray, EX-16 (measured from the top surface of the tray base to the top surface of the reinforcing material) was approximately 1 / 4 inch, which was relatively higher than the height of the reinforcing materials on the third tray, EX-17 (measured from the top surface of the tray base to the top surface of the reinforcing material), which was approximately 1 / 8 inch.

[0114] The fourth tray, EX-18, was constructed using multiple lateral, longitudinal, and diagonal reinforcing members (i.e., a total of 10 edge and corner reinforcing members). Specifically, the fourth tray, EX-18, was constructed similarly to the tray shown in Figure 12. The fifth tray, EX-19, was also constructed using multiple lateral, longitudinal, and diagonal reinforcing members (i.e., a total of 10 edge and corner reinforcing members). Specifically, the fifth tray, EX-19, was also constructed similarly to the tray shown in Figure 12. In contrast, the height of the reinforcing members of the fourth tray, EX-18 (measured from the top surface of the tray base to the top surface of the reinforcing member) was approximately 1 / 4 inch, which was relatively higher than the height of the reinforcing members of the fifth tray, EX-19 (measured from the top surface of the tray base to the top surface of the reinforcing member), which was approximately 1 / 8 inch.

[0115] The sixth tray, EX-20, is a control tray formed without any reinforcing materials, and is therefore constructed similarly to the tray shown in Figure 7. The seventh tray, EX-21, is constructed using multiple lateral, longitudinal, and diagonal reinforcing materials (i.e., a total of 10 edge and corner reinforcing materials). Specifically, the seventh tray, EX-21, is constructed similarly to the tray shown in Figure 12. The eighth tray, EX-22, is also constructed using multiple lateral, longitudinal, and diagonal reinforcing materials (i.e., a total of 10 edge and corner reinforcing materials). Specifically, the eighth tray, EX-22, is also constructed similarly to the tray shown in Figure 12. In contrast, the height of the reinforcing material on the eighth tray, EX-22 (measured from the top surface of the tray base to the top surface of the reinforcing material) was approximately 1 / 4 inch, which was relatively higher than the height of the reinforcing material on the seventh tray, EX-21 (measured from the top surface of the tray base to the top surface of the reinforcing material), which was approximately 1 / 8 inch.

[0116] [Table 4]

[0117] As shown above, each tray formed using reinforcing material showed improved rigidity compared to the control tray. Specifically, the second tray EX-16 showed a 17% improvement in rigidity compared to the control tray EX-15. The third tray EX-17 showed a 20% improvement in rigidity compared to the control tray EX-15. The fourth tray EX-18 showed a 30% improvement in rigidity compared to the control tray EX-15. The fifth tray EX-19 showed a 13% improvement in rigidity compared to the control tray EX-15. Similarly, the seventh tray EX-21 showed a 22% improvement in rigidity compared to the control tray EX-20. And the eighth tray EX-22 showed a 30% improvement in rigidity compared to the control tray EX-20.

[0118] In addition to the improvement in stiffness observed in trays with reinforcing materials, it was found that reducing the plasticizer content also improved stiffness. Specifically, control tray EX-20 had higher stiffness than control tray EX-15 despite being formed with a thinner thickness. Similarly, the seventh tray EX-21 had higher stiffness than the third tray EX-17, and the eighth tray EX-22 had higher stiffness than the second tray EX-16.

[0119] Example E Three foam trays were thermoformed from a foam sheet using a Hydrotrim Lab thermoformer. The thermoformer features a mold with upper and lower heating plates inside the oven. A timer was used to set the holding time inside the oven. Vacuum was used to draw the material into the mold, and plug assist was used for complex parts. The trays evaluated for this study were fabricated using vacuum alone, with the upper and lower plates heated to 260°C. The foam sheet was heated for 35 seconds to generate a sheet temperature of 182–188°C.

[0120] The foamed sheet contained cellulose acetate (Ds2.5) with 20% triacetin as a plasticizer and less than 2% stabilizers and colorants. The foamed sheet was molded using 1% Foamazol73S chemical blowing agent and 1% ABT1000 talc as a nucleating agent. The foamed sheet was prepared using 2.5% pentane as the main blowing agent. The melting temperature of the primary extruder was 210°C, and the melting temperature of the secondary extruder was 187°C. The foamed sheet was prepared at a pressure of 40 bar. The density of the foamed sheet was 0.109 g / cc, the sheet thickness was 5 mm, and the average cell size was 702 microns.

[0121] The resulting foam trays were 14 inches long, 8.6 inches wide, and 1.6 inches high (measured from the bottom surface of the tray base to the top surface of the tray rim). Three foam trays were molded using the method described above and tested using a tray stiffness test, as shown in Table 5 below.

[0122] The first tray, EX-23, was a control tray formed without any reinforcing materials and was therefore constructed similarly to the tray shown in Figure 7. The second tray, EX-24, was constructed using multiple lateral and longitudinal reinforcing materials (i.e., a total of 10 edge reinforcing materials). Specifically, the second tray, EX-24, was constructed using reinforcing materials similarly to the tray shown in Figure 11. The third tray, EX-25, was constructed using multiple lateral, longitudinal, and diagonal reinforcing materials (i.e., a total of 10 edge and corner reinforcing materials). Specifically, the third tray, EX-24, was constructed similarly to the tray shown in Figure 12. The height of each reinforcing material in the second tray, EX-24, and the third tray, EX-25 (measured from the top surface of the tray base to the top surface of the reinforcing material), was approximately 1 / 4 inch.

[0123] [Table 5]

[0124] As shown above, each tray formed using reinforcing material demonstrated improved rigidity compared to the control tray. Specifically, the second tray EX-24 showed a 40% improvement in rigidity compared to the control tray EX-23. The third tray EX-25 showed a 33% improvement in rigidity compared to the control tray EX-23.

[0125] definition It should be understood that the following is not intended to be an exclusive list of the terms to be defined. Other definitions, for example, when used in context, may be provided in the explanations above.

[0126] As used herein, the terms "a," "an," and "the" mean one or more.

[0127] As used herein, the terms “comprising,” “comprises,” and “comprise” are open-ended transitional clauses used to move the subject listed before the term to one or more elements listed after the term, the elements listed after the transitional clause are not necessarily the only elements that constitute the subject.

[0128] To be considered "depositable," the material must meet the following four criteria: (1) The material must pass the biodegradation requirement in tests under controlled deposition conditions at high temperature (58°C) according to ISO 14855-1 (2012), equivalent to 90% absolute biodegradation or 90% relative to the control polymer; (2) The material tested under aerobic deposition conditions according to ISO 16929 (2013) must reach 90% degradation; (3) The test material must meet all requirements for volatile solids, heavy metals, and fluorine as specified by ASTM D6400 (2012), EN 13432 (2000), and ISO 17088 (2012); (4) The material must not adversely affect plant growth.

[0129] As used herein, the term “biodegradability” generally refers to the biological transformation and consumption of organic molecules. Biodegradability is an inherent property of the material itself, and materials may exhibit different degrees of biodegradability depending on the specific conditions to which they are exposed. The term “disintegrability” refers to the tendency of a material to physically decompose into smaller fragments when exposed to specific conditions. Disintegration depends on both the material itself and the physical size and composition of the article being tested. Ecotoxicity measures the effect of a material on plants, and the heavy metal content of a material is determined according to the procedures presented in standard test methods.

[0130] For a material to be considered "biodegradable," it must exhibit at least 90 percent biodegradation in total under household composting conditions, according to French standard NFT51-800 and Australian standard AS5810 (for example, compared to the initial sample), or at least 90 percent of the maximum biodegradation of a suitable reference material after reaching a plateau for both the reference and test items. The maximum test period for biodegradation under household composting conditions is one year.

[0131] Under industrial deposition conditions in accordance with ASTMD6400 and ISO17088, for an article to be considered "biodegradable," at least 90% of the organic carbon in the whole article (or each component present in amounts greater than 1% by dry mass) must be converted to carbon dioxide by the end of the test period, compared to a control or absolute value. According to European standard ED13432 (2000), the material must exhibit at least 90 percent biodegradation in total, or at least 90 percent of the maximum biodegradation of a suitable reference material after reaching a plateau for both the reference and test items. The maximum test period for biodegradability under industrial composition conditions is 180 days.

[0132] To be considered "biodegradable" under soil deposition conditions according to Vincotte's OK Biodegradable Soil Conformity Mark and DINCERTCO's DINGeprruft Biodegradable Soil Certification Scheme, the material must exhibit at least 90% biodegradation in total (e.g., compared to the initial sample), or at least 90 percent of the maximum degradation of a suitable reference material after reaching a plateau for both the reference and test items. The maximum test period for biodegradability under soil deposition conditions is two years.

[0133] In one embodiment, or in combination with any of the embodiments referenced herein, the biodegradable cellulose acetate foam or article is industrially stackable or household stackable. In one subclass of this class, the foam or article is industrially stackable. In one subclass of this class, the foam or article has a thickness of less than 6 mm. In one subclass of this class, the foam or article has a thickness of less than 3 mm. In one subclass of this class, the article has a thickness of less than 1.1 mm. In one subclass of this class, the foam or article is household stackable. In one subclass of this class, the foam or article has a thickness of less than 6 mm. In one subclass of this class, the foam or article has a thickness of less than 3 mm. In one subclass of this class, the foam or article has a thickness of less than 1.1 mm. In one subclass of this class, the foam or article has a thickness of less than 0.8 mm. In one subclass of this class, the foam or article has a thickness of less than 0.6 mm. In one subclass of this subclass, the foam or article has a thickness of less than 0.4 mm.

[0134] In one embodiment, or in combination with any of the embodiments referenced herein, the thickness of the foam or article is 1–10 mm, 1–8 mm, 2–8 mm, 3–7 mm, 4–6 mm, about 4 mm, about 5 mm, about 6 mm, about 7 mm, or about 8 mm. However, it should be noted that the foam or article may have other, larger sizes. For example, in some embodiments, the foam or article may have a thickness of 0.5–24 inches, 1–15 inches, or 3–12 inches.

[0135] In one embodiment, or in combination with any other embodiment referenced herein, the foam or article exhibits more than 90% collapse after 12 weeks according to a collapse test protocol as described herein or alternatively, in accordance with ISO 16929 (2013).

[0136] The compositions used to produce biodegradable cellulose acetate foam may include other additives such as fillers, stabilizers, odor modifiers, waxes, compatibilizers, biodegradation accelerators, dyes, pigments, colorants, lubricants, antioxidants, viscosity modifiers, antifungal agents, heat stabilizers, antimicrobial agents, softeners, release agents, UV absorbers, and combinations thereof. Each additional additive may be present in the cellulose ester material in amounts of less than 10% by weight, less than 5% by weight, less than 4% by weight, less than 3% by weight, less than 2% by weight, or less than 1.0% by weight. It should be noted that for multiple categories of components in the cellulose acetate composition, the same type of compound or material may be specified or included. For example, polyethylene glycol (PEG) may function as a plasticizer or as an additive that does not function as a plasticizer, such as a hydrophilic polymer or a biodegradation accelerator. For example, low molecular weight PEG has a plasticizing effect, while high molecular weight PEG functions as a hydrophilic polymer but does not have a plasticizing effect.

[0137] In one embodiment, or in combination with any other embodiment referred to herein, the foam, composition, or foaming composition further comprises a photocatalyst. In one class of this embodiment, the photocatalyst is titanium dioxide or iron oxide. In one subclass of this class, the photocatalyst is titanium dioxide. In one subclass of this class, the photocatalyst is iron oxide.

[0138] In one embodiment, or in combination with any other embodiments referenced herein, the foam, composition, or foaming composition further comprises a pigment. In one class of this embodiment, the pigment is titanium dioxide, carbon black, or iron oxide. In one subclass of this class, the pigment is titanium dioxide. In one subclass of this class, the pigment is carbon black. In one subclass of this class, the pigment is iron oxide. In one subclass of this class, the pigment is a biodegradable particulate natural filler.

[0139] Claims not limited to the disclosed embodiments The preferred embodiments of the present invention described above are for illustrative purposes only and should not be used to limit the meaning of the interpretation of the scope of the invention. Modifications to the exemplary embodiments described above can be readily made by those skilled in the art without departing from the spirit of the invention.

[0140] The inventors hereby express their intention to determine and evaluate the reasonably fair scope of the invention on the basis of the doctrine of equivalents whenever the invention relates to any device that does not substantially deviate from, but falls outside, the literal scope of the invention as set forth in the following claims.

Claims

1. A foam tray molded from 50 to 99% by weight of cellulose ester, wherein the tray includes at least one elongated reinforcing member, the at least one elongated reinforcing member including a main reinforcing member extending laterally over at least 20% of the width of the tray, the main reinforcing member being positioned within 0.25 inches from the lateral centerline of the tray.

2. The foam tray according to claim 1, wherein the tray is configured to support food.

3. The foam tray according to claim 1 or 2, wherein the tray is configured to be wrapped in a film.

4. The foam tray according to any one of claims 1 to 3, wherein the tray is manufactured by thermoforming a sheet of cellulose ester foam.

5. The foam tray according to any one of claims 1 to 4, wherein the tray is biodegradable.

6. The foam tray according to any one of claims 1 to 5, wherein the cellulose ester is cellulose diacetate.

7. The foam tray according to any one of claims 1 to 6, wherein the tray contains a plasticizer in an amount of about 2% to about 40% by weight.

8. The foam tray according to claim 7, wherein the plasticizer comprises triacetin.

9. The foam tray according to any one of claims 1 to 8, wherein the at least one elongated reinforcing member comprises at least three reinforcing members.

10. The foam tray according to claim 9, wherein the at least three reinforcing members include the main reinforcing member, a first auxiliary reinforcing member, and a second auxiliary reinforcing member, the first auxiliary reinforcing member and the second auxiliary reinforcing member being arranged on both sides in the longitudinal direction of the main reinforcing member.

11. The foam tray according to claim 1, wherein the at least one elongated reinforcing member includes at least one longitudinally extending reinforcing member.

12. The foam tray according to claim 1, wherein the at least one elongated reinforcing member includes at least one reinforcing member extending in an oblique direction.

13. The foam tray according to claim 1, wherein the at least one elongated reinforcing member includes at least one ring-shaped reinforcing member.

14. The foam tray according to claim 1, wherein the tray comprises a base and a raised rim extending around the base, and the at least one elongated reinforcing member comprises a raised rib extending above the upper surface of the base.

15. The foam tray according to claim 14, wherein the at least one elongated reinforcing member extends 2 to 10 mm above the upper surface of the base of the foam tray.

16. The foam tray according to claim 14, wherein the at least one reinforcing member interconnects the base and the rim of the tray.

17. The foam tray according to any one of claims 1 to 16, wherein the tray has a width in the range of 5.08 to 35.56 cm and a length of 10.16 to 60.96 cm.

18. The foam tray according to claim 17, wherein the tray has a height of 2.54 to 7.62 cm.

19. The foam tray according to any one of claims 1 to 18, wherein the thickness of the tray is 1 to 10 mm.

20. The tray has a density of 0.20 g / cm³. ３ A foam tray according to any one of claims 1 to 19, having a density of less than [amount missing].

21. This is a process for manufacturing foam trays. (a) Extruding a mixed composition containing a cellulose ester in order to form a foamed sheet, wherein the cellulose ester is present in an amount of about 50% to about 99% by weight, (b) Thermoforming the foam sheet to form the foam tray, wherein the tray comprises at least one elongated reinforcing member, the at least one reinforcing member comprising a main reinforcing member extending laterally over at least 20% of the width of the tray, the main reinforcing member being positioned within 0.25 inches from the lateral centerline of the tray, The process including the process described above.

22. The process according to claim 21, wherein the tray is biodegradable.

23. The process according to claim 21 or 22, wherein the cellulose ester is cellulose diacetate, and the mixed composition contains a plasticizer present in an amount of about 2% to about 40% by weight, the plasticizer comprising triacetin.

24. The process according to any one of claims 21 to 24, wherein the at least one elongated reinforcing member comprises at least three reinforcing members, the at least three reinforcing members comprising the main reinforcing member, a first auxiliary reinforcing member, and a second auxiliary reinforcing member, the first auxiliary reinforcing member and the second auxiliary reinforcing member being arranged on both sides in the longitudinal direction of the main reinforcing member.

25. The process according to claim 21, wherein the at least one reinforcing member includes at least one longitudinally extending reinforcing member.

26. The process according to claim 21, wherein the at least one elongated reinforcing member includes at least one reinforcing member extending in an oblique direction.

27. The process according to claim 21, wherein the at least one elongated reinforcing member includes at least one ring-shaped reinforcing member.

28. The process according to claim 21, wherein the tray comprises a base and a raised rim extending around the base, the at least one elongated reinforcing member comprises a raised rib extending above the upper surface of the base, and the at least one elongated reinforcing member extends 2 to 10 mm above the upper surface of the base of the foam tray.

29. The process according to any one of claims 21 to 28, wherein the tray has a width of 2 to 12 inches, a length of 4 to 24 inches, and a height of 1 to 3 inches.

30. The thickness of the tray is 1 to 10 mm, and the tray is 0.20 g / cm². ３ The process according to any one of claims 21 to 29, having a density less than

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