Polymer extrusion process using vented extruder

Abstract

Compositions, systems, and methods for use in foam sheet production processes. Such processes generally comprise an extrusion process, which may utilize a vented extruder and an injection extruder. Embodiments of the invention advantageously allow the material to be extruded without a separate drying step by removing the moisture content through the vented extruder.

Description

POLYMER EXTRUSION PROCESS USING VENTED EXTRUDERBACKGROUND OF THE INVENTION

[0001] Many foam articles, such as food-packaging articles, are single-use items that are intended to be disposed of after use. One commercially important material used to make foam articles is polystyrene. However, polystyrene is neither compostable nor biodegradable. Moreover, some municipalities, states, and countries have enacted, or are considering enacting, bans on the use polystyrene-based foams. Thus, it would be desirable to find alternative materials for use in foam articles, as well as viable compositions, methods, and systems for producing such articles.

[0002] During sheet production processes, polymer pellets must traditionally be dried before introduction into an extrusion process. However, such drying processes can be excessively energy and cost intensive. Thus, it would be desirable to find processes that reduce or eliminate the need for a drying step.SUMMARY OF THE INVENTION

[0003] In one embodiment or in combination with any other embodiment mentioned herein, there is provided a method of extruding a cellulose ester composition. The method comprises: (a) providing a quantity of cellulose ester particulates; and (b) introducing at least a portion of the quantity of particulates directly into an extrusion process comprising a vented extruder to form a melt composition.

[0004] In one embodiment or in combination with any other embodiment mentioned herein, there is provided a method of extruding a cellulose ester composition. The method comprises: (a) providing a cellulose ester material; and (b) introducing at least a portion of the cellulose ester material directly into an extrusion process comprising a twin-screw vented extruder to form a melt composition.

[0005] In one embodiment or in combination with any other embodiment mentioned herein, there is provided an extrusion process. The processcomprises: (a) providing a quantity of bio-based polymer particulates; (b) introducing at least a portion of the quantity of particulates into an extruder barrel without drying the at least a portion of the quantity of particulates, to thereby form a melt composition; and (c) extruding the melt composition.

[0006] In one embodiment or in combination with any other embodiment mentioned herein, there is provided an extrusion process. The extrusion process comprises: (a) introducing a bio-based polymer material into a twin- screw vented extruder barrel without drying the bio-based polymer material, to thereby form a melt composition; and (b) extruding the melt composition.

[0007] In one embodiment or in combination with any other embodiment mentioned herein, there is provided a foamed extrusion process. The process comprises: (a) introducing a bio-based polymer material into a vented extruder to form a melt composition; (b) introducing at least a portion of the melt composition into an injection extruder; and (c) injecting a blowing agent into the melt composition via the injection extruder, thereby forming a foamed composition.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG 1 is a schematic diagram illustrating a biodegradable article forming process according to embodiments of the present invention;

[0009] FIG. 2 is a schematic diagram illustrating another biodegradable article forming process according to embodiments of the present invention;

[0010] FIG. 3 is a schematic diagram illustrating an extrusion section that may be used in the article forming processes of FIGS. 1 and / or 2, according to embodiments of the present invention;

[0011] FIG. 4 is a schematic diagram illustrating a multi-step extrusion section that may be used in the article forming process of FIGS. 1 and 2, according to embodiments of the present invention; and

[0012] FIG. 5 is a schematic diagram illustrating a sheet forming section that may be used in the article forming processes of FIGS. 1 and / or 2, according to embodiments of the present invention.DETAILED DESCRIPTION

[0013] Embodiments are generally directed to methods, systems, and compositions for forming bio-based particulate materials (e.g., pellets), sheets (e.g., foam sheets), and articles. Exemplary processes including the methods, systems, and compositions are depicted in FIGS. 1 - 5 and are described in greater detail below.Methods and Systems

[0014] As shown in FIG. 1 and FIG. 2, raw materials may be introduced to a bio-based polymer production process, which produces a bio-based polymer material. As used herein, the term “bio-based” refers to a polymer material composed in whole, or in significant part of, biological products or renewable raw materials. In one embodiment or in combination with any other embodiment mentioned herein, the renewable raw materials comprise one or more renewable agriculture materials. In one embodiment or in combination with any other embodiment mentioned herein, the bio-based polymer material comprises one or more cellulose esters. The one or more cellulose esters may comprise cellulose acetates. In such embodiments, the raw materials may comprise a pulp, such as wood pulp and / or cotton pulp. The pulp may be a dissolving-grade pulp and / or a paper-grade pulp. The cellulose in the pulp may be esterified, for example with an acetic acid, to form the bio-based cellulose ester polymer, such as a cellulose acetate polymer.

[0015] The bio-based polymer material may then be introduced into a compounding process, in which the bio-based polymer material may be mixed with plasticizer, and optionally one or more other additives (e.g., stabilizers), and formed into a compounded material comprising plasticized biodegradable polymer. Other additives may also be mixed with the polymer and plasticizer. For example, as shown in FIG. 2, the other materials (additives) may include, but are not limited to, stabilizers, physical blowing agent(s), chemical blowing agent(s) (and / or precursors), nucleating agent(s), surface modifying additive(s),pigment(s), filler(s), and / or other additive(s). Additional details regarding the polymers and additives that may be included in the composition are provided below. Mixing can be accomplished by any known mixing technique, including, but not limited to, rolling in a cylindrical container, overhead stirring, sigma blade mixing, and tumbling.

[0016] The compounding process may include a particulating process. The particulating process may generally comprise mixing the bio-based polymer material, plasticizer, and other additive(s) to form a mixed composition and forming particulate material from the composition. In particular, the particulating process may include a pelletization process, and the particulate material may comprise a quantity of pellets. The term “compounded material” means biobased material formed during the compounding process, which may include a mixture of bio-based polymer, plasticizer, and other additives. Further such compounded material may be in the form of particulate material or pellets. It should be understood that, as used herein, the phrases “particulating” or “particulating processes” may be the same as, or may at least include, “pelletizing” or “pelletizing processes.” In some embodiments, the particulating process may include pelletizing into a water bath, pelletizing on an air-cooled belt, underwater pelletizing, solvent compounding, etc.

[0017] In one embodiment or in combination with any other embodiment mentioned herein, the plasticizer and other additive(s) may be mixed with the bio-based polymer by conventional melt compounding techniques, which involve combining the cellulose ester with plasticizer, and optionally the other additives, in a twin screw extruder with appropriate mixing elements and at appropriate temperatures and pressures to achieve a molten, homogeneously combined, mixture by the time the materials exit the extruder. The molten, compounded, mixture may then be extruded through a die with orifices that are about 2-6 mm in diameter so as to extrude a strand. This strand may then be cooled by water (e.g., via underwater pelletization) or air and cut at regular intervals to provide a uniform and desirable size and shape, referred to as “pellets” or “granules.” Although a process for forming pelletized compounded material is described herein, it will be understood that the compounded materialfed to the foam sheet production process can be in any physical shape (e.g., pellets, flakes, powders, granules, fibers) in accordance with some embodiments. The term “compounded material” means bio-based polymer material formed during the compounding process, which may include a mixture of cellulose ester, plasticizer, and other additives. Further such compounded material may be in the form of a molten mixture or a particulate material (e.g., pellets, flakes, powders, granules, fibers, etc.)

[0018] The compounded material, which as noted above may comprise pellets of plasticized bio-based polymer, may then be introduced into a sheet production process, as illustrated in FIGS. 1 and 2. The sheet production process may include one or more zones / steps for producing a sheet or film, which are described in greater detail below. Although an exemplary foam sheet production process is described herein, it should be understood that certain aspects described herein may also be applicable to rigid (i.e., non-foamed) materials and articles. As shown in FIG. 1 , in one embodiment or in combination with any other embodiment mentioned herein, various additives may be introduced to one or more zones of the foam sheet production process. The additives may include, but are not limited to, stabilizers, physical blowing agent(s), chemical blowing agent(s) (and / or precursors), nucleating agent(s), surface modifying additive(s), pigment(s), filler(s), and / or other additive(s).

[0019] The foam sheet production process may generally include an extrusion section and a sheet forming section. An exemplary extrusion section is depicted in FIG. 3. As shown, the extrusion section may comprise a feed preparation zone, in which solid additives may be combined with the compounded material and introduced to the downstream extrusion zone. In one embodiment or in combination with any other embodiment mentioned herein, the feed preparation zone may comprise a feed hopper. Thus, the compounded material and the other solid additives may be deposited into the feed hopper, which directs the combined feed composition into the extrusion zone. The feed preparation zone may further comprise a mixer, in which the compounded material and one or more additive(s) may be mixed before being introduced to the hopper. Mixing can be accomplished by any known mixing technique,including, but not limited to, rolling in a cylindrical container, overhead stirring, sigma blade mixing, and tumbling. Exemplary solid additive(s) that can be combined with the compounded material may include chemical blowing agent(s), nucleating agent(s), surface modifying additive(s), pigment(s), filler(s), and / or other additive(s).

[0020] The combined feed composition from the feed preparation zone may then be introduction to the extrusion zone. The extrusion zone may generally comprise 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 an extruder barrel and conveyed, via the screw(s), through a die, which forms an extrudate from the feed composition. The composition may be heated, and at least partially melted, as it is conveyed through the extruder barrel toward the die. Thus, the term “melt composition” is used herein to mean the feed composition that has been melted into a flowable, molten resin via the extrusion section. Heating may be supplied by external heaters positioned along the outside of the extruder barrel. The shape of the extrudate will generally depend on the shape and size of the die head. The extrudate may be further shaped by downstream processes, as described below.

[0021] As depicted in FIG. 4, in one embodiment or in combination with any other embodiment mentioned herein, the extrusion zone may comprise a vented extrusion vessel, a primary extrusion vessel, and / or a cooling vessel. The primary extrusion vessel and cooling vessel may be separate devices or combined as a unitary apparatus. Regardless, the feed composition from the feed preparation zone is introduced into the vented extrusion vessel and at least partially melted as it is conveyed through the extruder barrel, as described above, to thereby produce a melt composition.

[0022] In one embodiment or in combination with any other embodiment mentioned herein, at least a portion of the particulates may be introduced directly into the extrusion zone. As used herein, the term “directly” means that one material is conveyed or otherwise transferred from one process operation to another process operation without an intermediary processing step. For example, the second process operation produced a different form of thematerial (e.g., article, shape, composition, moisture content) from the material produced by the first process operation. In some such embodiments, this means that the particulates may be introduced into the extrusion zone (or directly into an extruder barrel) without drying the particulates. In some embodiments, the particulates are introduced directly into a vented extruder (i.e., without subjecting the particulates to a drying step).

[0023] In one embodiment or in combination with any other embodiment mentioned herein, the moisture (e.g., water) content of the composition is reduced in the vented extruder. The vented extruder may generally comprise a material inlet, a melt outlet (i.e., exit of the extruder), and at least one vent port. As the material is heated, at least a portion of the water content is vaporized, and at least a portion of the vaporized water content can be removed through the at least one vent port. In some embodiments, the at least one vent port is positioned on the extruder barrel closer to the outlet than to the inlet. For example, the at least one vent port may be positioned at least 50%, at least 60%, at least 70%, or at least 80% down the extruder barrel.

[0024] In one embodiment or in combination with any other embodiment mentioned herein, the vapor exhaust stream removed through the at least one vent port comprises water and a plasticizer. In some embodiments, at least a portion of the vapor exhaust stream can be recycled for further use in one or more processes described herein. For example, the recycling process may comprise separating the water and the plasticizer to recover a water-enriched liquid stream and a plasticizer-enriched liquid stream. Any separation process may be used, such as distillation, liquid-liquid separation, or other refining process. In some embodiments, the refining process may comprise a filtration process (e.g., standard filtration or selective membrane) and / or a distillation process. Once separated, at least a portion of the plasticizer-enriched stream may be recycled for use as a plasticizer in a cellulose ester particulating process, such as described herein. In some embodiments, at least a portion of the plasticizer-enriched stream may be combined with another plasticizer stream before being introducing to the particulating process.

[0025] In one embodiment or in combination with any other embodiment mentioned herein, the vented extruder comprises a single screw extruder. In some such embodiments, the quantity of particulates has a moisture content of not more than 4.0 weight %, not more than 3.0 weight %, not more than 2.0 weight %, not more than 1 .0 weight %, not more than 0.9 weight %, not more than 0.8 weight %, not more than 0.7 weight %, not more than 0.6 weight %, or not more than 0.5 weight% when introduced into the single screw vented extruder. The quantity of particulates may have a moisture content of 0.01 weight % to 4.0 weight %, 0.1 weight % to 4.0 weight %, 0.2 weight % to 4.0 weight %, 0.5 weight % to 4.0 weight %, 0.01 weight % to 3.0 weight %, 0.1 weight % to 3.0 weight %, 0.2 weight % to 3.0 weight %, 0.5 weight % to 3.0 weight %, 0.01 weight % to 2.0 weight %, 0.1 weight % to 2.0 weight %, 0.2 weight % to 2.0 weight %, 0.5 weight % to 2.0 weight %, 0.01 weight % to 1 .0 weight %, 0.1 weight % to 1.0 weight %, 0.2 weight % to 1.0 weight %, 0.5 weight % to 1 .0 weight %, 0.1 weight % to 0.85 weight %, or 0.2 weight % to 0.75 weight % when introduced into the single screw vented extruder.

[0026] In one embodiment or in combination with any other embodiment mentioned herein, the vented extruder comprises a twin-screw extruder. In some such embodiments, the quantity of particulates has a moisture content of not more than 5.0 weight %, not more than 4.0 weight %, not more than 3.0 weight %, or not more than 2.0 weight % when introduced into the twin-screw vented extruder. The quantity of particulates may have a moisture content of 0.1 weight % to 5.0 weight %, 0.5 weight % to 5.0 weight %, 1 .0 weight % to 5.0 weight %, 1 .5 weight % to 5.0 weight %, 2.0 weight % to 5.0 weight %, 2.5 weight % to 5.0 weight %, 3.0 weight % to 5.0 weight %, 3.5 weight % to 5.0 weight %, 4.0 weight % to 5.0 weight %, 4.5 weight % to 5.0 weight %, 0.1 weight % to 4.0 weight %, 0.5 weight % to 4.0 weight %, 1 .0 weight % to 4.0 weight %, 1 .5 weight % to 4.0 weight %, 2.0 weight % to 4.0 weight %, 2.5 weight % to 4.0 weight %, 3.0 weight % to 4.0 weight %, 3.5 weight % to 4.0 weight %, 0.1 weight % to 3.0 weight %, 0.5 weight % to 3.0 weight %, 1.0 weight % to 3.0 weight %, 1 .5 weight % to 3.0 weight %, 2.0 weight % to 3.0 weight %, or 2.5 weight % to 3.0 weight %, when introduced into the twin-screwvented extruder. In some embodiments, the twin-screw extruder comprises two or more vent ports. For example, the twin-screw extruder may comprise at least a first vent port and a second vent port upstream of the first vent port. In some such embodiments, the first vent port is located closer to the outlet than to the inlet and / or the second vent port is located closer to the inlet than to the outlet. In some embodiments, the twin-screw vented extruder comprises a gear pump configured to maintain constant output through a shaping die at the extruder outlet.

[0027] The vented extruder advantageously reduces the moisture (water) content of the composition as it is melted and extruded through the extruder. In one embodiment or in combination with any other embodiment mentioned herein , the moisture content of the melt composition is reduced by at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, at least 98%, at least 99%, or at least 99.9% within the vented extruder. The moisture content of the melt composition is reduced by 50% to 99.9%, 60% to 99%, 70% to 98%, or 80% or 95%. In some embodiments, the moisture content of the melt composition is reduced to not more than 2000 ppm, not more than 1500 ppm, not more than 1200 ppm, not more than 1000 ppm, or not more than 800 ppm, within the vented extruder. The moisture content of the melt composition is reduced to 10 ppm to 2000 ppm, 50 ppm to 1500 ppm, 100 ppm to 1200 ppm, 100 ppm to 1000 ppm, or 100 to 800 ppm, within the vented extruder.

[0028] In one embodiment or in combination with any other embodiment mentioned herein, the material (e.g., quantity of particulates of polymer, such bio-based or biodegradable polymer, or more specifically a cellulose ester polymer or a cellulose acetate (e.g., cellulose diacetate) polymer) has a weight average molecular weight (Mw) in a range from 10,000 to 250,000, or 50,000 to 250,000, or 10,000 to 200,000, or 50,000 to 200,000, or 10,000 to 150,000, or 50,000 to 150,000, or 10,000 to 125,000, or 50,000 to 125,000, or 75,000 to 125,000, or 85,000 to 1 15,000, or 90,000 to 110,000, measured using gel permeation chromatography (GPC) when introduced into the vented extruder.

[0029] The vented extruder advantageously maintains the Mw of the polymer in the material as it is melted and extruded through the extruder. In oneembodiment or in combination with any other embodiment mentioned herein, the Mw of the polymer in the melt composition is maintained within at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or at least 99.9% within the vented extruder. The Mw of the polymer in the melt composition is maintained within 80% to 99.9%, 85% to 99%, 90% to 98%, or 92% to 98%.

[0030] In one embodiment or in combination with any other embodiment mentioned herein, at least a portion of the melt composition from the vented extruder is introduced into an injection extruder. As used herein, the term “Injection extruder” refers to an extruder equipped with one or more injection ports for introducing materials to the melt composition being extruded. It will be understood by those of skill in the art that the injection extruder (and injection extrusion) is separate from injection molding equipment (and injection molding processes). In some embodiments, a blowing agent (such as described herein) may be injected into the melt composition via an injection port, thereby causing the melt composition to foam. The injection extruder may generally comprise an inlet, outlet, and at least one injection port. Due to the composition being melted in the vented extruder, the injection port may advantageously be located further upstream on the injection extruder than traditional injection extruder processes. For example, in some embodiments, the injection port may be located at a position closer to the inlet than to the outlet.

[0031] The melt composition exiting the injection extruder may have a temperature from about 220° C to about 240° C.

[0032] In one embodiment or in combination with any other embodiment mentioned herein, the foamed composition exiting the injection extruder may be introduced into a cooling unit to lower the temperature of the foamed composition before forming through an extruder die. In some embodiments, the cooling unit may be a cooling extruder or a cooling mixer unit (i.e., a melt cooler). The cooling unit lowers the temperature of the foamed composition by at least 10 ° C, at least 20 ° C, at least 30 ° C, at least 40 ° C, at least 50 ° C, at least 60 ° C, at least 70 ° C, or at least 80 ° C. The cooling unit may lower the temperature by 10° C to 100° C, or 20° C to 80° C.

[0033] The cooling vessel may be a secondary extrusion vessel, which operates similarly to, but at a lower temperature than, the primary extrusion vessel. Within the cooling vessel, the melt composition may be further mixed to provide a substantially homogenous mixture of the melted polymer and other additive(s). The melt composition may then be directed through the die and out of the die head to provide an extrudate, which may be further processed in the sheet forming section of the foam sheet production process. In one embodiment or in combination with any other embodiment mentioned herein, the melt composition 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, from about 150° C to about 220° C, and / or from about 170° C to about 200° C.

[0034] As shown in FIG. 4, one or more filtration devices may be installed within the extrusion section to filter and remove particulate matter from the melt composition. For example, screen changer filtration devices may be installed at the downstream end of the primary and secondary extrusion vessels, which may remove solid components from the melt composition before directing the melt compositions through the die head to the sheet forming section.

[0035] The sheet forming section may include any of a variety of systems and processes for shaping the extrudate into sheets of cellulose ester material that may be used in article formation. The shape of the extrudate will generally depend on the shape of the die head, while the shape of the sheets formed in the sheet forming section can depend on the shape of the die head and other downstream processes. For example, the extrudate may have a generally flat shape, or it may be annular and subjected to further processing to form a flat sheet. In embodiments in which the die has an annular shape, the die may have a diameter from 1 to 40 cm, from 2 to 20 cm, 2 to 10 cm, and / or 3 to 8 cm. Furthermore, the thickness of the opening from which extrudate is ejected, which is referred to herein as a “die gap,” may generally be sized from 0.1 to 6.0 mm, from 0.1 to 3.0 mm, and / or from 0.1 to 1 .0 mm.

[0036] An exemplary sheet forming section is depicted in FIG. 5. As shown, the CE melt composition is extruded through an annular die and drawn over a forming mandrel. A cooling fluid (e.g., air) may be flowed across the interiorand / or exterior of the extrudate to cool the extrudate material as it passes over the mandrel. For example, the cooling fluid may be blown from the mandrel toward the die to cool the interior surface of the extrudate between the die and mandrel. Additionally, or alternatively, the cooling fluid may be flowed across the mandrel to cool the exterior surface of the extrudate as it passes over the mandrel. In some embodiments, the tubular extrudate is cooled by a cooling ring positioned encircling the mandrel. In certain embodiments, the cooling ring is positioned at a distance of at least 1 foot, at least 2 feet, or at least 3 feet from the annular die. A heating gaseous (vapor) stream (e.g., air) may be fed through an interior portion of the mandrel, for example, to ensure the extrudate remains sufficiently inflated so that the extrudate can be continuously drawn over the mandrel. In some embodiments, the heating vapor stream may comprise air, nitrogen, or carbon dioxide, although other gaseous components may also be used.

[0037] Referring again to FIG. 5, a slicer (or slitting device) may be used to open the tubular extrudate, which allows the tubular shape to be formed into a flat sheet. For example, the tubular extrudate passing over the mandrel may be slit and drawn to a tensioning station comprising one or more rollers that flatten the extrudate and maintain a necessary amount of tension on the extrudate to continue pulling the extrudate over the mandrel. The flattened extrudate will generally be in the form of a sheet, which may then be directed to a winding station where the material may be rolled for packaging and transportation.

[0038] Referring again to FIG. 1 and FIG. 2, the sheets produced by the sheet production process may be used to form foam articles, which are described in greater detail below. Such articles are particularly useful in the food service industry. Exemplary articles include meat trays. The articles may have one or more particularly advantageous properties. For example, the articles may be biodegradable and / or compostable, and / or the articles may have superior mechanical properties (e.g., strength, density, cell size, absorption, etc.).Compositions

[0039] The processes described above may comprise the preparation and extrusion of compositions that may be used for downstream processing to form useful articles. For example, in one embodiment or in combination with any other embodiment mentioned herein, the extrusion feed material may comprise a particulate material comprising a bio-based or biodegradable polymer and optionally one or more additive(s), such as those described herein. In one embodiment or in combination with any other embodiment mentioned herein, the feed material may be combined with one or more additive(s), such as those described herein, to provide a mixed composition comprising the bio-based polymer and the one or more additive(s).

[0040] In one embodiment or in combination with any other embodiment mentioned herein, the bio-based polymer material comprises a polymer selected from the group consisting of aliphatic polyesters, aliphatic aromatic polyesters, cellulose esters, and combinations or blends thereof. In some embodiments, the composition comprises one or more additives selected from buildup resistant additives, chemical blowing agents, physical blowing agents (e.g., hydrocarbon blowing agents), surface modifying additives (e.g., slip agents), and / or biodegradable polymers (such as polyethylene glycol (PEG) and others described herein).

[0041] Additional details of the composition components, including biodegradable polymers (e.g., cellulose esters) and other additives, are provided below.Cellulose Ester

[0042] The cellulose esters utilized as described herein can be any that is known in the art. Cellulose ester that can be used for embodiments herein generally comprise repeating units of the structure:1 2 2 wherein R , R , and R are selected independently from the group consisting of hydrogen acetyl, propyl or butyl. The substitution level of the cellulose ester is usually expressed in terms of degree of substitution (DS), which is the average number of non-OH substituents per anhydroglucose unit (AGU). Generally, conventional cellulose contains three hydroxyl groups in each AGU unit that can be substituted; therefore, DS can have a value between zero and three. Native cellulose is a large polysaccharide with a degree of polymerization from 250 - 5,000 even after pulping and purification, and thus the assumption that the maximum DS is 3.0 is approximately correct. Because DS is a statistical mean value, a value of 1 does not assure that every AGU has a single substituent. In some cases, there can be unsubstituted anhydroglucose units, some with two and some with three substituents, and typically the value will be a non-integer. Total DS is defined as the average number of all of substituents per anhydroglucose unit. The degree of substitution per AGU can also refer to a particular substituent, such as, for example, hydroxyl or acetyl. In one embodiment or in combination with any other embodiment, n is an integer in a range from 25 to 250, or 25 to 200, or 25 to 150, or 25 to 100, or 25 to 75.

[0043] In one embodiment or in combination with any other embodiment, the cellulose esters have at least 2 anhydroglucose rings and can have between at least 50 and up to 5,000 anhydroglucose rings, or at least 50 and less than 150 anhydroglucose rings. The number of anhydroglucose 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, cellulose esters can have an inherent 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, as measured at a temperature of 25°C for a 0.25 gram sample in 100 ml of a 60 / 40 by weight solution ofphenol / tetrachloroethane. In one embodiment or in combination with any other embodiment, cellulose esters useful herein can have a DS / AGU of about 1 to about 3.0 of about 2.2 to about 2.8, or 1 to less than 2.2, or 1 to less than 1 .5, and the substituting ester is acetyl.

[0044] Cellulose esters can be produced by any method known in the art. Examples of processes for producing cellulose esters are 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 in different grades and sources such as from cotton linters, softwood pulp, hardwood pulp, corn fiber and other agricultural sources, and bacterial cellulose, among others.

[0045] One method of producing cellulose esters is esterification of the cellulose by mixing cellulose with the appropriate organic acids, acid anhydrides, and catalysts. Cellulose is then converted to a cellulose triester. Ester hydrolysis is then performed by adding a water-acid mixture to the cellulose triester, which can then be filtered to remove any gel particles or fibers. Water is then added to the mixture to precipitate the cellulose ester. The cellulose ester can then be washed with water to remove reaction by-products followed by dewatering and drying.

[0046] The cellulose triesters to be hydrolyzed can 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 the homogeneous acylation of cellulose dissolved in an appropriate solvent such as LiCI / DMAc or LiCI / NMP.

[0047] Those skilled in the art will understand that the commercial term of cellulose triesters also encompasses cellulose esters that are not completely substituted with acyl groups. For example, cellulose triacetate commercially available from Eastman Chemical Company, Kingsport, TN, U.S.A., typically has a DS from about 2.85 to about 2.99.

[0048] After esterification of the cellulose to the triester, part of the acyl substituents can be removed by hydrolysis or by alcoholysis to give a secondary cellulose ester. As noted previously, depending on the particular method employed, the distribution of the acyl substituents can be random or non-random. Secondary cellulose esters can also be prepared directly with no hydrolysis by using a limiting amount of acylating reagent. This process is particularly useful when the reaction is conducted in a solvent that will dissolve cellulose. All of these methods yield cellulose esters that are useful in this invention.

[0049] In one embodiment or in combination with any of the mentioned embodiments, the cellulose acetates are cellulose diacetates that have a polystyrene equivalent number average molecular weight (Mn) from about 10,000 to about 100,000 as measured by gel permeation chromatography (GPC) using NMP as solvent and polystyrene equivalent Mn according to ASTM D6474. In one embodiment or in combination with any other embodiment, the cellulose acetate composition comprises cellulose diacetate having a polystyrene equivalent number average molecular weights (Mn) from 10,000 to 90,000; or 10,000 to 80,000; or 10,000 to 70,000; or 10,000 to 60,000; or 10,000 to less than 60,000; or 10,000 to less than 55,000; or 10,000 to 50,000; or 10,000 to less than 50,000; or 10,000 to less than 45,000; or 10,000 to 40,000; or 10,000 to 30,000; or 20,000 to less than 60,000; or 20,000 to less than 55,000; or 20,000 to 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 less than 60,000; or 30,000 to less than 55,000; or 30,000 to 50,000; or 30,000 to less than 50,000; or 30,000 to less than 45,000; or 30,000 to 40,000; or 30,000 to 35,000; as measured by gel permeation chromatography (GPC) using NMP as solvent and according to ASTM D6474.

[0050] The most common commercial secondary cellulose esters are prepared by initial acid catalyzed heterogeneous acylation of cellulose to form the cellulose triester. After a homogeneous solution in the corresponding carboxylic acid of the cellulose triester is obtained, the cellulose triester is then subjected to hydrolysis until the desired degree of substitution is obtained. Afterisolation, a random secondary cellulose ester is obtained. That is, the relative degree of substitution (RDS) at each hydroxyl is roughly equal.

[0051] The cellulose esters useful in the present invention can be prepared using techniques known in the art, and can be chosen from various types of cellulose esters, such as for example the cellulose esters that can be obtained from Eastman Chemical Company, Kingsport, TN, U.S.A., e.g., Eastman™ Cellulose Acetate CA 398-30 and Eastman™ Cellulose Acetate CA 398-10, Eastman™ CAP 485-20 cellulose acetate propionate; Eastman™ CAB 381 -2 cellulose acetate butyrate.

[0052] In one embodiment or in combination with any other embodiment, the cellulose ester can be prepared by converting cellulose to a cellulose ester with reactants that are obtained from recycled materials, e.g., a recycled plastic content syngas source. In one embodiment or in combination with any other embodiment, such reactants can be cellulose reactants that include organic acids and / or acid anhydrides used in the esterification or acylation reactions of the cellulose, e.g., as discussed herein.

[0053] In one embodiment or in combination with any of the mentioned embodiments, or in combination with any of the mentioned embodiments, of the invention, a cellulose ester composition comprising at least one recycle cellulose ester is provided, wherein the cellulose ester has at least one substituent on an anhydroglucose unit (AU) derived from recycled content material, e.g., recycled plastic content syngas.

[0054] In one embodiment or in combination with any other embodiment, the cellulose ester composition comprises cellulose ester in an amount from 50 to 99 wt%, or 60 to 99 wt%, or 70 to 99 wt%, or 80 to 99 wt%, from 50 to 98 wt%, or 60 to 98 wt%, or 70 to 98 wt%, or 80 to 98 wt, or 90 to 98 wt%, 50 to 90 wt%, or 60 to 90 wt%, or 70 to 90 wt%, or 80 to 90 wt%, or 90 to 99 wt%, or 50 to 80 wt%, or 60 to 80 wt%, or 70 to 80 wt%, or 50 to 70 wt%, or 60 to 70 wt%, or 50 to 60 wt%, all based on the total weight of the cellulose ester composition. In some embodiments, the cellulose ester used herein may comprise a combination, blend, or mixture of two or more different types of cellulose esters. For example, in some embodiments, the cellulose esters used herein may becomprised of a blend of two or cellulose esters having differing DSACs; however, the blend may have a total DSAC of between 2.2 and 2.8Plasticizer

[0055] In one embodiment or in combination with any other embodiment, the cellulose ester compositions described herein can comprise at least one plasticizer. The plasticizer reduces the melt temperature, i.e., the Tg, and / or the melt viscosity of the cellulose ester. Plasticizers for cellulose esters may include glycerol triacetate (Triacetin), glycerol diacetate (Diacetin), dibutyl terephthalate, dimethyl phthalate, diethyl phthalate, polyethylene glycol) MW 200-600, dibutyl tartrate, di-2-methoxyethyl phthalate, ethyl o- benzoylbenzoate, triethylene glycol dipropionate, 1 ,2-epoxypropylphenyl ethylene glycol, 1 ,2-epoxypropyl(m-cresyl) ethylene glycol, 1 ,2-epoxypropyl(o- cresyl) ethylene glycol, p-oxyethyl cyclohexenecarboxylate, bis(cyclohexanate) diethylene glycol, triethyl citrate, polyethylene glycol, propylene glycol, polysorbate, sucrose octaacetate, acetylated triethyl citrate, acetyl tributyl citrate, Admex, tripropionin, Scandiflex, poloxamer copolymers, polyethylene glycol succinate, diisobutyl adipate, polyvinyl pyrollidone, and glycol tribenzoate, the benzoate containing plasticizers such as the Benzoflex™ plasticizer series, poly (alkyl succinates) such as poly (butyl succinate), polyethersulfones, o-Cresyl p-toluenesulfonate, n- ethyltoluenesulfonamides, adipate based plasticizers, soybean oil epoxides such as the Paraplex™ plasticizer series, sucrose based plasticizers, dibutyl sebacate, tributyrin, sucrose acetate isobutyrate, the Resolflex™ series of plasticizers, triphenyl phosphate (TPP), triethyl phosphate (TEP), glycolates (e.g., ethyl phthalyl ethyl glycolate “EPEG” and methyl phthalyl ethyl glycolate “MPEG”), methoxy polyethylene glycol, 2,2,4-trimethylpentane-1 ,3-diyl bis(2- methylpropanoate), and polycaprolactones. In some embodiments, the plasticizer used herein may comprise a combination or mixture of two or more different types of plasticizers.

[0056] In one embodiment or in combination with any other embodiment, has a boiling point of at least 100 °C, or at least 200 °C, and / or not more than 400 °C, or not more than 300 °C.

[0057] In one embodiment or in combination with any other embodiment, the plasticizer is a food-compliant plasticizer. By food-compliant is meant compliant with applicable food additive and / or food contact regulations where the plasticizer is cleared for use or recognized as safe by at least one (national or regional) food safety regulatory agency (or organization), for example listed in the 21 CFR Food Additive Regulations or otherwise Generally Recognized as Safe (GRAS) by the US FDA. In one embodiment or in combination with any other embodiment, the food-compliant 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, examples of food- compliant plasticizers that could be considered can include triacetin, triethyl citrate, polyethylene glycol, Benzoflex, propylene glycol, polysorbate, sucrose octaacetate, acetylated triethyl citrate, acetyl tributyl citrate, Admex, tripropionin, Scandiflex, poloxamer copolymers, polyethylene glycol succinate, diisobutyl adipate, polyvinyl pyrollidone, and glycol tribenzoate.

[0058] In one embodiment or in combination with any other embodiment, the plasticizer can be present in an amount sufficient to permit the cellulose ester composition to be melt processed (or thermally formed) into useful articles, e.g., single use plastic articles, in conventional melt processing equipment. In one embodiment or in combination with any other embodiment, the plasticizer is present in an amount from 1 to 40 wt% for most thermoplastics processing; or 5 to 25 wt%, or 10 to 25 wt%, or 12 to 20 wt% based on the weight of the cellulose ester composition. In one embodiment or in combination with any other embodiment, profile extrusion, sheet extrusion, thermoforming, and injection molding can be accomplished with plasticizer levels in the 10-30, or 12-25, or 15-20, or 10-25 wt% range, based on the weight of the cellulose ester composition.

[0059] In one embodiment or in combination with any other embodiment, the plasticizer is a biodegradable plasticizer. Some examples of biodegradableplasticizers include triacetin, triethyl citrate, acetyl triethyl citrate, polyethylene glycol, the benzoate containing plasticizers such as the Benzoflex™ plasticizer series, poly (alkyl succinates) such as poly (butyl succinate), polyethersulfones, adipate based plasticizers, soybean oil epoxides such as the Paraplex™ plasticizer series, sucrose based plasticizers, dibutyl sebacate, tributyrin, the Resoflex™ series of plasticizers, triphenyl phosphate, glycolates, polyethylene glycol, 2,2,4-trimethylpentane-1 ,3-diyl bis(2-methylpropanoate), and polycaprolactones.

[0060] In one embodiment or in combination with any other embodiment, the cellulose ester composition can contain a plasticizer selected from the group consisting of PEG and MPEG (methoxy PEG). The polyethylene glycol or a methoxy polyethylene glycol composition having an average molecular weight of from 200 Daltons to 600 Daltons, wherein the composition is melt processable, biodegradable, and disintegrable.

[0061] In one embodiment or in combination with any other embodiment, the composition comprises polyethylene glycol or methoxy PEG having an average molecular weight of from 300 to 550 Daltons.

[0062] In one embodiment or in combination with any other embodiment, the composition comprises polyethylene glycol having an average molecular weight of from 300 to 500 Daltons.

[0063] In one embodiment or in combination with any other embodiment, the cellulose ester composition comprises at least one plasticizer (as described herein) in an amount from 1 to 40 wt%, or 5 to 40 wt%, or 10 to 40 wt%, or 12 to 40 wt%, 13 to 40 wt%, or 15 to 40 wt%, or greater than 15 to 40 wt%, or 17 to 40 wt%, or 20 to 40 wt%, or 25 to 40 wt%, or 5 to 35 wt%, or 10 to 35 wt%, or 13 to 35 wt%, or 15 to 35 wt%, or greater than 15 to 35 wt%, or 17 to 35 wt%, or 20 to 35 wt%, or 5 to 30 wt%, or 10 to 30 wt%, or 13 to 30 wt%, or 15 to 30 wt%, or greater than 15 to 30 wt%, or 17 to 30 wt%, or 5 to 25 wt%, or 10 to 25 wt%, or 13 to 25 wt%, or 15 to 25 wt%, or greater than 15 to 25 wt%, or 17 to 25 wt%, or 5 to 20 wt%, or 10 to 20 wt%, or 13 to 20 wt%, or 15 to 20 wt%, or greater than 15 to 20 wt%, or 17 to 20 wt%, or 5 to 17 wt%, or 10 to 17 wt%, or 13 to 17 wt%, or 15 to 17 wt%, or greater than 15 to 17 wt%, or 5 to less than17 wt%, or 10 to less than 17 wt%, or 13 to less than 17 wt%, or 15 to less than 17 wt%, all based on the total weight of the cellulose ester composition.

[0064] In one embodiment or in combination with any other embodiment, the at least one plasticizer includes or is a food-compliant or FDA approved plasticizer. In one embodiment or in combination with any other embodiment, the food-compliant or FDA approved plasticizer includes or is triacetin or PEG MW 300 to 500.Biodegradable Polymers

[0065] In one embodiment or in combination with any other embodiment, the cellulose ester compositions described herein comprise a biodegradable cellulose ester (BCE) component that comprises at least one BCE, which may include one or more of the cellulose esters described herein, and a biodegradable polymer component that comprises at least one other biodegradable polymer (other than the BCE). In one embodiment or in combination with any other embodiment, the other biodegradable polymer can be chosen from polyhydroxyalkanoates (PHAs and PHBs), polylactic acid (PLA), poly(glycolic acid) (PGA), polycaprolactone polymers (PCL), polybutylene adipate terephthalate (PBAT), polyethylene succinate (PES), polyvinyl acetates (PVAs), polybutylene succinate (PBS) and copolymers (such as polybutylene succinate-co-adipate (PBSA)), cellulose esters, cellulose ethers, starch (including modified starches), proteins, derivatives thereof, and combinations thereof. In one embodiment or in combination with any other embodiment, the cellulose ester composition comprises two or more biodegradable polymers.

[0066] In one embodiment or in combination with any other embodiment, the cellulose ester compositions described herein comprise cellulose ester blends with one or more biodegradable polymers that can enhance the melt strength and / or increase the elasticity of the composition. Particularly preferred biodegradable polymers include those that have high biodegradability, low Tg (e.g., below room temperature), and / or low modulus.

[0067] In one embodiment or in combination with any other embodiment, the biodegradable polymer is selected from polyethylene succinate (PES), poly(glycolic acid) (PGA), starches (including modified starches), and mixtures thereof. In some such embodiments, these biodegradable polymers can provide increased blow-up ratios when combined with cellulose acetate.

[0068] In one embodiment or in combination with any other embodiment, the biodegradable polymer is selected from polybutylene succinate (PBS) and copolymers (such as polybutylene succinate-co-adipate (PBSA)), polyhydroxyalkanoates (PHAs and PHBs), polybutylene adipate terephthalate (PBAT), polylactic acid (PLA), starch (including modified starches), and mixtures thereof. In some such embodiments, these biodegradable polymers can provide increased blow-up ratios when combined with cellulose acetate propionate (CAP) and / or cellulose acetate butyrate (CAB).

[0069] In one embodiment or in combination with any other embodiment, the cellulose ester composition contains a biodegradable polymer (other than the BCE) in an amount from 0.1 to less than 50 wt%, or 1 to 40 wt%, or 1 to 30 wt%, or 1 to 25 wt%, or 1 to 20 wt%, 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 the BCE) in an amount from 0.1 to less than 50 wt%, or 1 to 40 wt%, or 1 to 30 wt%, or 1 to 25 wt%, or 1 to 20 wt%, based on the total amount of BCE and biodegradable polymer. In one embodiment or in combination with any other embodiment, the at least one biodegradable polymer comprises a PHA having a weight average molecular weight (Mw) in a range from 10,000 to 1 ,000,000, or 50,000 to 1 ,000,000, or 100,000 to 1 ,000,000, or 250,000 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, measured using gel permeation chromatography (GPC) with a refractive index detector and polystyrene standards employing a solvent of methylene chloride. In one embodiment or in combination with any other embodiment, the PHA can include a polyhydroxybutyrate-co- hydroxyhexanoate.Nucleating Agent

[0070] Nucleating agent means a chemical or physical material that provides sites for cells to form in a molten formulation mixture, such as within a melt composition. As will be described in more detail below, nucleating agents may be added to compounded material during the compounding process. Alternatively, or in addition, nucleating agents may be added during the foam sheet production process. For example, the nucleating agents may be blended with the formulation that is introduced into the hopper of the extruder of the extruding section. Alternatively, the nucleating agents may be added to the melt composition in the extruder itself. Nucleating agents may include physical nucleating agents and chemical nucleating agents. Physical nucleating agents are materials that are immiscible with the polymer matrix of the melt composition at the extrusion temperature of the extrusion section. Chemical nucleating agents are materials that react (e.g., decompose) during extrusion (e.g., at the extrusion temperature within the extruder) to form physical nucleating agents. Thus, chemical nucleating agents may be considered (and referred to herein as) precursors of in situ formed physical nucleating agents.

[0071] Suitable physical nucleating agents will comprise fine particles having desirable particle sizes and / or shapes to create cell nucleation sites within the melt composition. For example, in some embodiments, physical nucleating agents will have a mean 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 microns. However, in some other embodiments, it may be preferred to have nanoscale-sized particles. Furthermore, it some embodiments, physical nucleating agents will preferably have a high aspect ratio (i.e., width: height). For example, in some embodiments, physical nucleating agents will have a mean aspect ratio of 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 still, as noted above, physicalnucleating agents should be immiscible with the polymer matrix of the melt composition at the extrusion temperature of the extrusion section. As such, in some embodiments, the physical nucleating agents should have a melting temperature at least 220° C, at least 230° C of 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. Nevertheless, the physical nucleating agents may be selected such that they have the ability to, after melting, recrystallize upon cooling.

[0072] Examples of suitable inorganic physical nucleating agents include, but are not limited to, minerals such as talc, CaCOs, mica, and mixtures of at least two of the foregoing. One representative example is Heritage Plastics HT6000 Linear Low Density Polyethylene (LLDPE) Based Talc Concentrate. Other inorganic physical nucleating agents include wollastonite, silica, silicon oxide, titanium oxide, magnesium oxide, aluminum oxide and calcium silicate, barium sulfate, Kaolin, aluminum tryhydrateATH (AI(OH)3), MDH (Mg(OH)2), Diatomaceous earth, magnetite / hematite, halloysite, zinc oxide, and titanium dioxide. In some embodiments, the inorganic nucleating agents will comprise oxides, such as metal oxides or mixed metal oxides, such as those 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 oxide, and titanium oxide. In other embodiments, the inorganic nucleating agents will comprise silicates, such as silicates selected from one or of the following: magnesium silicate and calcium silicate.

[0073] It has been discovered that biodegradable natural, particulate materials derived from renewable organic sources (e.g., organic nucleating agents) can also serve as effective physical nucleating agents. Natural materials that can be physical nucleating agents include material comprised of cellulose fibers and / or cellulose starch. Examples include, but are not limited to almond shell flour, animal fiber, apricot shell flour, bamboo flour, tree bark flour, clam shell flour, coconut shell flour, coconut coir, corn flour, corn cob flour, corn cob grit, cottonseed hulls, flock & fiber, hazelnut shell flour, kenaf flour, natural fibers, nutshell hull & flour, oat fiber powder, olive stone flour, peanut hulls flour,pecan shell flour, pine-nut shell powder, pistachio-nut shell flour, plant fiber, rice hull flour, rice hull grit, rice husk, soy bean flour, starch flour (hydrophobic), walnut shell flour, wheat chaff, wheat husk, and wood flour. Other organic physical nucleating agents include cellulose powder, chitin, chitosan, stearic acid metal salts, carbon black, and dolomite.

[0074] As noted above, suitable chemical nucleating agents (or precursors of in situ formed physical nucleating agents) are configured to decompose to create cell nucleation sites in the melt composition when a threshold chemical reaction temperature is reached. These small cells act as nucleation sites for larger cell growth from a physical or other type of blowing agent. In some embodiments, the precursors are configured to form a gas during extrusion of the particulate material, such as CO2 or N2.

[0075] Examples of chemical nucleating agents include but are not limited to acids, such as citric acid or a citric acid-based material. Other acids may include lauric acid, stearic acid, tartaric acid, ascorbic acid, propionic acid, and hexanoic acid. One representative example is HYDROCEROL™ CF-40E (available from Clariant Corporation), which contains citric acid and a crystal nucleating agent. In some embodiments, the chemical nucleating agents will include a combination of an acid and a base, such as a carbonate, which may include sodium bicarbonate, zinc bicarbonate, potassium bicarbonate, sodium carbonate, potassium carbonate, etc. For instance, a representative example of a chemical nucleating agent is a combination of citric acid and sodium bicarbonate. In some embodiments, chemical nucleating agents may include a carrier within which the active components of the nucleating agents are dispersed. For example, yet another representative example of chemical nucleating agents is a combination of citric acid, sodium bicarbonate, and a carrier. In some embodiments, the carrier may comprise polystyrene. However, the carrier may comprise other compositions, such as various biopolymers (e.g., polybutylene succinate, Capa polyesters, etc.), polyolefins, acrylic copolymers (e.g., ethylene methyl acrylate), or the like. In some such embodiments, the citric acid and sodium bicarbonate may comprise about half (in wt%) of the chemical nucleating agents, while the carrier makes up theremaining half (in wt%). Furthermore, in some of such embodiments, there may be more sodium bicarbonate than citric acid in the chemical nucleating agent. For instance, there may be about three times as much (in wt%) sodium bicarbonate than citric acid in the chemical nucleating agent. It should also be understood that in some embodiments, no carrier may be required or used, such as the case with the nucleating agent being Hecofoam or HydroceroL

[0076] In one embodiment or in combination with any of the embodiments mentioned herein, the nucleating agents are present at from 0.1 to 10 wt%, from 0.1 to 5.0 wt%, at least 0.1 wt%, at least 0.25 wt%, at least 0.5 wt% at least 1 .0 wt%, at least 1 .25 wt%, at least 1 .5 wt%, at least 1 .75 wt%, at least 2.0 wt%, at least 2.25 wt%, at least 2.5 wt%, at least 2.75 wt%, or at least 3.0 wt%, or at least 3.5 wt%, or at least 4.0 wt%, or at least 4.5 wt% and / or less than 7.5 wt%, less than 5 wt%, less than 4 wt%, less than 3 wt%, less than 2 wt%, or less than 1 .0 wt%, all based on the total weight of the cellulose ester composition. In some embodiments, the nucleating agents used herein may comprise a combination or mixture of two or more different types of nucleating agents.

[0077] It is noted that the cellulose ester material, whether in the form of compounded material or melt composition, will generally be able to accept a maximum amount of nucleating agent that can function to form nucleation sites. Any remaining nucleating agent that is added to the cellulose ester material will remain as filler. Fillers can provide various properties to the resulting cellulose ester foams and / or articles based on the type of filler used. For example, some fillers can provide increased / decreased density, ductility, Young’s modulus, yield strength, heat deflection temperature, permeability, impact resistance, elongation to break, adhesion properties, biodegradation, etc. of the cellulose ester material. Fillers can also be used to alter the visual characteristics (e.g., color, opacity, etc.) and tactile characteristics (e.g., material continuous, surface roughness, etc.) of the cellulose ester material.Blowing Agents

[0078] A blowing agent refers to a physical or a chemical material (or combination of materials) that acts to expand nucleation sites. Blowing agentsmay include chemical blowing agents, physical blowing agents, combinations thereof, or several types of chemical and physical blowing agents. The blowing agents function to reduce density of a material by expanding cells formed in the molten formulation at the nucleation sites. The blowing agent may be added to the melt composition in the extruder. It has been surprisingly discovered that the hygroscopic nature of biodegradable particulate natural fillers allows them to absorb moisture and carry the absorbed water into the molten resin mixture where the water can act as a physical blowing agent.

[0079] Examples of physical blowing agents include H2O, N2, CO2, alkanes, alkenes, ethers, ketones, argon, helium, air or mixtures. In addition, it has been surprisingly discovered that the hygroscopic nature of biodegradable particulate natural fillers allows them to absorb moisture and carry the absorbed water into the molten resin mixture where the water can act as a physical blowing agent. Hygroscopic biodegradable natural fillers can be formulated into a composition and allowed to absorb moisture prior to the foaming process, where the water then is released to act as a physical blowing agent. Beneficially, the water may also be used as a plasticizer for the cellulose ester resin. Furthermore, in some embodiments, physical blowing agents may include hydrocarbons, such as pentane / isopentane or butane / isobutane. Other hydrocarbons may include propane, ethane, methane, hexane, cyclohexane, cyclopentane, cyclobutene, or the like.

[0080] Chemical blowing agents are materials that degrade or react to produce a gas (e.g., CO2or N2). Such gasses expand the cells within the molten resin mixture and / or resulting foam mixture to produce a structural material with a plurality of gaseous voids dispersed throughout. Chemical blowing agents may be endothermic or exothermic. Chemical blowing agents typically degrade at a certain temperature to decompose and release gas. Examples of chemical blowing agents include azodicarbonamide, acids (e.g., citric acid), and carbonates, such as sodium bicarbonate, sodium carbonate, ammonium bicarbonate, ammonium carbonate, zinc carbonate, and the like and combinations thereof.

[0081] In one embodiment or in combination with any of the embodiments mentioned herein, the blowing agents described above may be combined with a secondary blowing agent (or co-blowing agent). In some embodiments, the co-blowing agent is selected from the group consisting of methyl acetate, ethanol, ketones (e.g., acetone), and mixtures thereof.

[0082] In one embodiment or in combination with any of the embodiments mentioned herein, the blowing agent (and any co-blowing agent) is present at from 0.3 to 1 .5 wt%, or 0.3 to 2.0 wt%, or 0.3 to 2.5 wt%, or 0.3 to 3.0 wt%, or 0.3 to 3.5 wt%, or 0.3 to 4.0 wt%, or 0.3 to 8%, or 1 .3 to 1 .5 wt%, or 1 .3 to 2.0 wt%, or 1 .3 to 2.5 wt%, or 1 .3 to 3.0 wt%, or 1 .3 to 3.5 wt%, or 1 .3 to 4.0 wt%, or 1 .3 to 4.5 wt%, or 1 .3 to 5.0 wt%, or 1 .3 to 5.5 wt%, or 1 .5 to 3.0 wt%, or 1 .5 to 4.0 wt%, or 1 .5 to 5.0 wt%, or 1 .5 to 6.0 wt%, or 2.0 to 3.0 wt%, or 2.0 to 4.0 wt%, or 2.0 to 5.0 wt%, or 2.0 to 6.0 wt%, or 2.5 to 3.0 wt%, or 2.5 to 4.0 wt%, or 2.5 to 5.0 wt%, or 2.5 to 6.0 wt%, or 3.0 to 4.0 wt%, or 3.0 to 5.0 wt%, or 3.0 to 6.0 wt%, or 0.0 to 9.0 wt%, or 0.5 to 9.0 wt%, or 1 .0 to 9.0 wt%, or 1 .5 to 9.0 wt%, or 2.0 to 9.0 wt%, or 2.5 to 9.0 wt%, or 3.0 to 9.0 wt%, or 3.5 to 9.0 wt%, or 4.0 to 9.0 wt%, or 4.5 to 9.0 wt%, or 5.0 to 9.0 wt%, or 5.5 to 9.0 wt%, or 6.0 to 9.0 wt%, or 6.5 to 9.0 wt%, or 7.0 to 9.0 wt%, or 7.5 to 9.0 wt%, or 8.0 to 9.0 wt%, or 8.5 to 9.0 wt%, all based on the total weight of the cellulose ester composition. In some embodiments, the blowing agents used herein may comprise a combination or mixture of two or more different types of blowing agents.Surface Modifying Additives

[0083] Surface modifying additives refer to materials that can be added to cellulose ester compositions to modify the structure of the compositions (or the resulting foam articles) to improve processing of the cellulose ester compositions. For example, the inventors of the present application have found that adding surface modifying additives to the compounded material (e.g., to the pellets during the compounding process) or to the melt composition (e.g., during the extrusion process) can improve processing by reducing unwanted sticking of the melt composition to the die or mandrel (or to other componentsof the foam sheet production process). Such reduction in sticking may be achieved by the surface modifying additives inhibiting the fusing of cellulose esters caused by plasticizers. The addition of surface modifying additives may also reduce blocking of the cellulose ester foam sheets produced at the sheet forming section. Furthermore, surface modifying additives may also improve the foam sheet production process by allowing the process to be performed at lower temperatures and / or allowing for increased blow-up ratios when drawing the melt compositions over forming mandrels.

[0084] Furthermore still, in some embodiments, the surface modifying additives may function as anti-static additives, which inhibit electrical sparks or arcing in the melt composition. The inhibition of electrical sparks or arcing can be particularly important when hydrocarbons are used as blowing agents, so as to reduce the chance of igniting the hydrocarbons and causing fires. Beneficially, surface modifying additives may also reduce the diffusion of blowing agents, such as hydrocarbons, out of the foam sheets or resulting articles. In some embodiments, hydrocarbons themselves may be used as surface modifying additives.

[0085] Nevertheless, more general examples of surface modifying additives that may be used with compounded material (e.g., during the compounding process) or to the melt composition (e.g., during the foam sheet production process) according to embodiments of the present invention include fatty acids, such as palmitic acid, tallow acid, stearic acid, oleic acid, linoleic and linolenic acids, arachidic / behenic acids, behenic acid, and erucic acid. Surface modifying additives may also include fatty acid amides, such as erucamides, oleoamides, stearmides, bhenamides, secondary amides, and bisamides.

[0086] Additional examples of surface modifying additives may include glycerol esters and / or stearate esters, such as monoglycerides, diglycerides, and triglycerides. The monoglycerides may include glycerol monostearate or monoglyceride derivatives, such as diacetyl tartaric acid esters of mono- and diglycerides (DATEM), ethoxylated monoglyceride, succinyl monoglyceride, and propylene glycol monoesters (PGME). Examples of surface modifying additives may also include metallic stearates such as aluminum stearate,calcium stearate, lithium stearate, magnesium stearate, sodium stearate, zinc stearate, and / or combinations thereof (e.g., Calcium / Zinc stearates) . Examples of surface modifying additives may also include waxes, such as polyolefin waxes (polypropylene wax and polyethylene wax), oxidized olefin waxes, ethylene acrylic acid (EAA) copolymer waxes, ethylene methyl acrylate (EMA) copolymer waxes, EAA ionomer axes, acrylic waxes, and / or natural waxes, such as rice bran wax, sunflower wax, sugar cane wax, candelilla wax, soy wax, bees wax, candelilla wax, and carnauba waxes.

[0087] Other, non-exclusive examples of surface modifying additives include aliphatic diesters (e.g., dioctyl adipate), polyglycol diesters, alkyl alkyether diesters, aromatic triesters, polyester resins, chlorinated hydrocarbons, halogenated hydrocarbons, alkylether monoesters, and alkyl monoesters. In addition, various oils may be used as surface modifying additives, such as aromatic oils, napthenic oils, glyceride oils, silicon oils, and epoxidized oils (e.g., soybean oil and linseed oil). Thus, in some embodiments, the surface modifying additives comprise plasticizers, such as aliphatic diester plasticizers, polyester plasticizers, and the like. Furthermore, in some embodiments, surface modifying additives may comprise a polyhedral oligomeric silsesquioxane (POSS).

[0088] More generally, surface modifying additives used in embodiments of the present invention may have a lower polarity than the cellulose ester in compounded material (e.g., during the compounding process) or to the melt composition (e.g., during the foam sheet production process). For example, the surface modifying additives may have (based on Hansen solubility parameters): a total solubility parameter 5 of less than 25 MPa1 / 2, less than 20 MPa1 / 2, or less than 19.5 MPa1 / 2; a dispersion force solubility parameter bd of less than 18 MPa1 / 2, less than 16 MPa1 / 2, or less than 14 MPa1 / 2; a dipolar intermolecular force solubility parameter bd of less than 12 MPa1 / 2, less than 8 MPa1 / 2, or less than 4 MPa1 / 2; and / or a hydrogen bond solubility parameter bh of less than 1 1 MPa1 / 2, less than 10 MPa1 / 2, or less than 9 MPa1 / 2. However, in some other embodiments, the surface modifying additives used in embodiments of the present invention may have a higher polarity than the cellulose ester incompounded material (e.g., during the compounding process) or to the melt composition (e.g., during the foam sheet production process). For example, the surface modifying additives may have (based on Hansen solubility parameters): a total solubility parameter 5 of more than 21.5 MPa1 / 2, more than 23 MPa1 / 2, or more than 25 MPa1 / 2. In addition, in some embodiments, surface modifying additives may have a boiling point greater than 200° C, greater than 220° C, greater than 240° C, greater than 260° C, greater than 280° C, or greater than 300° C. Furthermore, the surface modifying additives may have a molecular weight greater than 100 g / mol, greater than 150 g / mol, greater than 220 g / mol, greater than 260 g / mol, greater than 300 g / mol, or greater than 340 g / mol and / or no more than 1000 g / mol, no more than 2500 g / mol, or no more than 5000 g / mol. Furthermore still, it may be preferable for the surface modifying additives to not be soluble in the plasticizer(s) used in the cellulose ester compositions. For instance, it may be preferable for the surface modifying additives to not be soluble in triacetin. Finally, in some embodiments, the surface modifying additives may be biodegradable and / or food-compliant or FDA approved.

[0089] In one embodiment or in combination with any of the embodiments mentioned herein, the surface modifying additives are present at from 0.05 to 0.75 wt%, or 0.05 to 1 .0 wt%, or 0.05 to 2.5 wt%, or 0.05 to 5.0 wt%, or 0.75 to 1 .0 wt%, or 0.75 to 2.5 wt%, or 0.75 to 5.0 wt%, or 0.1 to 1 .0 wt%, or 0.1 to 2.5 wt%, 0.1 to 5.0 wt%, or 1 .0 to 2.5 wt%, or 1 .0 to 5.0 wt%, or 2.5 to 5.0 wt%, all based on the total weight of the cellulose ester composition. In some embodiments, the surface modifying additives used herein may comprise a combination or mixture of two or more different types of surface modifying additives.Articles

[0090] Extruded sheets of cellulose ester foam may be formed using the extrusion section and / or the sheet forming section described above. Such extruded sheets of comprise a structural material with a plurality of gaseous voids disposed throughout. Such gaseous voids are formed by expansion ofthe blowing agent in the form of a gas within the cellulose polymer melt. The structural material is cellulose ester based, with specific amounts of the compositional components of the structural material (e.g., cellulose ester, plasticizer, nucleating agents, surface modifying additives, etc.) having been described above in more detail. Articles may be formed from the extruded sheets of foam in accordance with embodiments, and may be particularly useful in the food service industry. Exemplary articles include meat trays. The articles may have one or more particularly advantageous properties. For example, the articles may be biodegradable and / or compostable, and / or the articles may have superior mechanical properties (e.g., strength, density, cell size, absorption, etc.).

[0091] In one embodiment or in combination with any of the embodiments mentioned herein, the foam has a density less than 0.20 g / cm3, less than 0.18 g / cm3, less than 0.15 g / cm3, less than 0.12 g / cm3, less than less than 0.10 g / cm3, less than 0.08 g / cm3, less than less than 0.06 g / cm3, or less than less than 0.04 g / cm3, or from 0.04 to 0.8 g / cm3, 0.04 to 0.6 g / cm3, 0.04 to 0.5 g / cm3, 0.04 to 0.4 g / cm3, 0.04 to 0.3 g / cm3, 0.04 to 0.2 g / cm3, 0.04 to 0.15 g / cm3, 0.04 to 0.12 g / cm3, 0.04 to 0.10 g / cm3, 0.04 to 0.08 g / cm3, 0.04 to 0.06 g / cm3, 0.06 to 0.8 g / cm3, 0.06 to 0.6 g / cm3, 0.06 to 0.5 g / cm3, 0.06 to 0.4 g / cm3, 0.06 to 0.3 g / cm3, 0.06 to 0.2 g / cm3, 0.06 to 0.15 g / cm3, 0.06 to 0.12 g / cm3, 0.06 to 0.10 g / cm3, 0.06 to 0.08 g / cm3, 0.08 to 0.8 g / cm3, 0.08 to 0.6 g / cm3, 0.08 to 0.5 g / cm3, 0.08 to 0.4 g / cm3, 0.08 to 0.3 g / cm3, 0.08 to 0.2 g / cm3, 0.08 to 0.15 g / cm3, 0.08 to 0.12 g / cm3, 0.08 to 0.10 g / cm3, 0.1 to 0.8 g / cm3, 0.1 to 0.6 g / cm3, 0.1 to 0.5 g / cm3, 0.1 to 0.4 g / cm3, 0.1 to 0.3 g / cm3, 0.1 to 0.2 g / cm3, 0.1 to 0.15 g / cm3, 0.1 to 0.12 g / cm3, 0.2 to 0.8 g / cm3, 0.2 to 0.6 g / cm3, 0.2 to 0.5 g / cm3, 0.2 to 0.4 g / cm3, 0.2 to 0.3 g / cm3, 0.3 to 0.6 g / cm3, 0.3 to 0.5 g / cm3, 0.3 to 0.4 g / cm3, 0.4 to 0.6 g / cm3, 0.4 to 0.5 g / cm3, or 0.5 to 0.6 g / cm3.

[0092] In one embodiment or in combination with any of the embodiments mentioned herein, the average foam cell size is from 40 pm to 600 pm, or 50 pm to 600 pm, or 60 pm to 600 pm, or 70 pm to 600 pm, or 80 pm to 600 pm, or 90 pm to 600 pm, or 100 pm to 600 pm, or 150 pm to 600 pm, or 200 pm to 600 pm, or 250 pm to 600 pm, or 300 pm to 600 pm, or 400 pm to 600 pm, or500 pm to 600 pm, or 40 pm to 550 pm, or 40 pm to 500 pm, or 40 pm to 450 pm, or 40 pm to 400 pm, or 40 pm to 350 pm, or 40 pm to 300 pm, or 40 pm to 250 pm, or 40 pm to 200 pm, or 40 pm to 150 pm, or 40 pm to 100 pm.Further Inventive Concepts Related to Processes and Systems for Producing Pellets, Foam Sheets, and / or Articles.

[0093] As described above, embodiments of the present invention processes and systems for the production of biodegradable cellulose ester compositions, sheets, and articles. The embodiments described herein are particularly useful in the production of cellulose ester foamed sheets and articles, although the embodiments may be utilized in other sheet and article production applications.

[0094] In one embodiment or in combination with any of the embodiments mentioned herein, a biodegradable cellulose acetate foam or article may be produced that is industrial compostable or home compostable. In one subclass of this class, the foam or article is industrial compostable. In one sub-subclass of this subclass, the foam or article has a thickness that is less than 6 mm. In one sub-subclass of this subclass, the foam or article has a thickness that is less than 3 mm. In one sub-subclass of this subclass, the article has a thickness that is less than 1.1 mm. In one subclass of this class, the foam or article is home compostable. In one sub-subclass of this subclass, the foam or article has a thickness that is less than 6 mm. In one sub-subclass of this subclass, the foam or article has a thickness that is less than 3 mm. In one sub-subclass of this subclass, the foam or article has a thickness that is less than 1 .1 mm. In one sub-subclass of this subclass, the foam or article has a thickness that is less than 0.8 mm. In one sub-subclass of this subclass, the foam or article has a thickness that is less than 0.6 mm. In one sub-subclass of this subclass, the foam or article has a thickness that is less than 0.4 mm.

[0095] In one embodiment or in combination with any of the embodiments mentioned herein, the thickness of the foam or article is from 1 to 10 mm, from 1 to 8 mm, from 2 to 8 mm, from 3 to 7 mm, from 4 to 6 mm, about 4 mm, about 5 mm, about 6 mm, about 7 mm, or about 8 mm. However, it should be notedthat the foam or article may have other, larger sizes. For example, in some embodiments, the foam or article may have a thickness from 0.5 to 24 inches, from 1 to 15 inches, or 3 to 12 inches. In some embodiments, the foam or article may have a thickness of from 100-400 mils, 120-300 mils, or 150-250 mils.

[0096] In one embodiment or in combination with any of the embodiments mentioned herein, the foam or article exhibits greater than 90% disintegration after 12 weeks according to the disintegration test protocol for films, as described in the specification.

[0097] The compositions used to prepare the biodegradable cellulose acetate foams can comprise other additives such as fillers, stabilizers, odor modifiers, waxes, compatibilizers, biodegradation promoters, dyes, pigments, colorants, lubricants, anti-oxidants, viscosity modifiers, antifungal agents, heat stabilizers, antibacterial agents, softening agents, mold release agents, UV absorbers, and combinations thereof. Each additional additive may be present in the cellulose ester-based material in an amount less than 10 wt. %, less than 5 wt. % less than 4 wt. %, less than 3 wt. %, less than 2 wt. %, or less than 1 .0 wt. %. It should be noted that the same type of compounds or materials can be identified for or included in multiple categories of components in the cellulose acetate compositions. For example, polyethylene glycol (PEG) could function as a plasticizer or as an additive that does not function as a plasticizer, such as a hydrophilic polymer or biodegradation promotor, e.g., where a lower molecular weight PEG has a plasticizing effect and a higher molecular weight PEG functions as a hydrophilic polymer but without plasticizing effect.

[0098] In one embodiment or in combination with any other embodiment mentioned herein, the foam, composition or foamable composition further comprises a photodegradation catalyst. In one class of this embodiment, the photodegradation catalyst is a titanium dioxide, or an iron oxide. In one subclass of this class, the photodegradation catalyst is a titanium dioxide. In one subclass of this class, the photodegradation catalyst is an iron oxide.

[0099] In one embodiment or in combination with any other embodiment mentioned herein, the foam, composition, or foamable composition further comprises a pigment. In one class of this embodiment, the pigment is a titaniumdioxide, a carbon black, or an iron oxide. In one subclass of this class, the pigment is a titanium dioxide. In one subclass of this class, the pigment is a carbon black. In one subclass of this class, the pigment is an iron oxide. In one subclass of this class, the pigment is a biodegradable particulate natural filler.Examples

[0100] The following examples illustrate how cellulose ester-based materials can be melt processed without the need for traditional drying processes / steps (for the cellulose ester-based material) before introduction of the material into an extrusion process, while retaining desired properties for the melt processed material.

[0101] The material used in the examples was Eastman Aventa FT1200, which is a formulated cellulose diacetate (CDA) that is plasticized with a 20 wt% target amount of triacetin plasticizer. The CDA had a target total degree of substitution of 2.45. The material was equilibrated to a starting moisture level of approximately 0.6 to 0.8 wt% or approximately 2.9 to 3.1 wt%.

[0102] Test samples were made to study the ability of a vented extruder to remove moisture from the starting material for both a single screw extruder and a twin-screw extruder.Examples 1 -9 (Single screw extruder)

[0103] Samples were made using a 1 .5” Killion single screw extruder having a 30:1 L / D. The vent location was 2 / 3 down the barrel at zone 3 location. The material was extruded at either 20, 40, or 60 rpms that represented outputs of 15, 25 and 30 Ibs / hr. Samples were extruded through a single hole die having a 1 / 8thdie opening onto a moving belt where they were air cooled and pelletized. Initial moisture content was measured before feeding the material to the extruder and then samples were collected and moisture content on the extruded samples were tested and compared to the initial moisture content for various process configurations.

[0104] The extruder was run with two different temperature profiles as shown in Table 1 below.Table 1 : Single Screw Extrusion Profile

[0105] Example 1 -9 samples were produced under various process conditions of extruder speed, temperature profile and venting at atmospheric or under vacuum. The results for moisture removal under the various conditions for the single screw extruder are shown below in Table 2.Table 2: Single Screw Extrusion Moisture Removal

[0106] A review of table 2 reveals that single screw extruders with vents can reduce starting moisture below 2000ppm when atmospheric vents are used and less than 1500ppm when vacuum vents are used. The was observed at moisture levels starting at > 7000ppm as well as > 27000 ppm.

[0107] Initial weight average molecular weight (Mw) was measured before feeding the material to the extruder and then samples were collected and Mwon the extruded samples were tested and compared to the initial Mw for various process configurations. The results for Mw change under the various conditions for the single screw extruder are shown below in Table 3.Table 3: Single Screw Extrusion Molecular Weight RetentionExamples 10-21 (Twin-screw extruder)

[0108] Samples were made using a 26mm Coperion extruder having a 44:1 L / D. The machine was configured to either be vacuum only venting or a combination of atmospheric vents and vacuum venting. The vacuum vent was located at zone 10. The two atmospheric vents were located at zone 3 and zone 5. When only one atmospheric vent was used, the vent at location zone 3 was coupled with the vacuum vent. Materials were extruded at 300rpms at melt temperatures of 212-213°C for the Temp 3 profile and 238-243°C for the Temp 4 profile. Materials were air cooled on a belt, pelletized and then tested for moisture retention / removal.

[0109] The twin-screw extruder was run with two different temperature profiles as shown in Table 4 below.Table 4: Twin Screw Extrusion Profile

[0110] Example 10-21 samples were produced under various process conditions of temperature profile and combinations of venting at atmospheric and / or under vacuum. The results for moisture removal under the various conditions for the twin screw extruder are shown below in Table 5.Table 5: Twin Screw Extrusion Moisture Removal

[0111] A review of table 5 reveals that twin screw extruders with vents can reduce starting moisture below 1500ppm when vacuum vents are used and below 1000 ppm when combinations of vacuum vents and atmospheric vents are used. The was observed at moisture levels starting at > 6500ppm as well as > 29000 ppm.

[0112] Further, a review of tables 2 and 5 reveals that use of either extruder (single or twin) can provide a means to avoid traditional drying requirements, where typical drying conditions for the Aventa CDA resin is 60C with time depending on the initial moisture levels, usually 6 to 8 hrs at moisture levels <1wt%, but up to 12 to 16 hrs at moisture levels > 2wt %.

[0113] Initial weight average molecular weight (Mw) was measured before feeding the material to the extruder and then samples were collected and Mw on the extruded samples were tested and compared to the initial Mw for various process configurations. The results for Mw change under the various conditions for the twin screw extruder are shown below in Table 6.Table 6: Twin Screw Extrusion Molecular Weight Retention

[0114] A review of table 6 reveals that there was greater than a 95% retention of molecular weight (Mw) while effectively removing moisture from the CDA material.DEFINITIONS

[0115] It should be understood that the following is not intended to be an exclusive list of defined terms. Other definitions may be provided in the foregoing description, such as, for example, when accompanying the use of a defined term in context.

[0116] As used herein, the terms “a,” “an,” and “the” mean one or more.

[0117] As used herein, the terms “comprising,” “comprises,” and “comprise” are open-ended transition terms used to transition from a subject recited before the term to one or more elements recited after the term, where the element or elements listed after the transition term are not necessarily the only elements that make up the subject.

[0118] To be considered “compostable,” a material must meet the following four criteria: (1 ) the material should pass biodegradation requirement in a test under controlled composting conditions at elevated temperature (58°C) according to ISO 14855-1 (2012) which correspond to an absolute 90% biodegradation or a relative 90% to a control polymer, (2) the material tested under aerobic composting condition according to ISO16929 (2013) must reach a 90% disintegration ; (3) the test material must fulfill all the requirements on volatile solids, heavy metals and fluorine as stipulated by ASTM D6400 (2012), EN 13432 (2000) and ISO 17088 (2012); and (4) the material should not cause negative on plant growth.

[0119] As used herein, the term “biodegradable” generally refers to the biological conversion and consumption of organic molecules. Biodegradability is an intrinsic property of the material itself, and the material can exhibit differentdegrees of biodegradability, depending on the specific conditions to which it is exposed. The term “disintegrate” refers to the tendency of a material to physically decompose into smaller fragments when exposed to certain conditions. Disintegration depends both on the material itself, as well as the physical size and configuration of the article being tested. Ecotoxicity measures the impact of the material on plant life, and the heavy metal content of the material is determined according to the procedures laid out in the standard test method.

[0120] To be considered “biodegradable,” under home composting conditions according to the French norm NF T 51-800 and the Australian standard AS 5810, a material must exhibit a biodegradation of at least 90 percent in total (e.g., as compared to the initial sample), or a biodegradation of at least 90 percent of the maximum degradation of a suitable reference material after a plateau has been reached for both the reference and test item. The maximum test duration for biodegradation under home compositing conditions is 1 year.

[0121] To be considered “biodegradable,” under industrial composting conditions according to ASTM D6400 and ISO 17088, at least 90 percent of the organic carbon in the whole item (or for each constituent present in an amount of more than 1 % by dry mass) must be converted to carbon dioxide by the end of the test period when compared to the control or in absolute. According to European standard ED 13432 (2000), a material must exhibit a biodegradation of at least 90 percent in total, or a biodegradation of at least 90 percent of the maximum degradation of a suitable reference material after a plateau has been reached for both the reference and test item. The maximum test duration for biodegradability under industrial compositing conditions is 180 days.

[0122] In order to be considered “biodegradable,” under soil composting conditions according the OK biodegradable SOIL conformity mark of Vingotte and the DIN Gepruft Biodegradable in soil certification scheme of DIN CERTCO, a material must exhibit a biodegradation of at least 90 percent in total (e.g., as compared to the initial sample), or a biodegradation of at least 90 percent of the maximum degradation of a suitable reference material after aplateau has been reached for both the reference and test item. The maximum test duration for biodegradability under soil compositing conditions is 2 years.

[0123] As used herein, “Injection extruder” refers to an extruder equipped with one or more injection ports for introducing materials to the melt composition being extruded. It will be understood by those of skill in the art that the injection extruder (and injection extrusion) is separate from injection molding equipment (and injection molding processes).

[0124] As used herein, the term “blow up ratio” means the ratio of the inner diameter of the extruder die to the outer diameter of the outer mandrel.

[0125] Unless specified otherwise, as used herein the absolute “Weight Average Molecular Weight” (or Mw) for cellulose esters is determined by GPC Analysis with the following parameters: Solvent: Tetrahydrofuran stabilized with BHT Preservative; Temperature: 30° C; Flow rate: 1.0 ml / min; Sample solution: 25 mg Cellulose Ester in 10 ml Tetrahydrofuran with BHT preservative + 10 pl toluene flow rate marker; Injection volume: 50 pl; Column set: Polymer Laboratories 5 pm PLgel, Guard + Mixed C + Oligopore; Detection: Refractive Index; Calibrants: monodisperse polystyrene standards, MW = 580 to 3,220,000 from Polymer Laboratories; Universal calibration parameters: PS - K = 0.0001280 and a = 0.7120, and CA - K = 0.00007572 and a = 0.8424. The universal calibration parameters above were determined by light scattering and viscometery to yield the correct weight average molecular weights.ADDITIONAL EMBODIMENTS

[0126] In a first aspect, a method of extruding a cellulose ester composition is provided, the method comprising: (a) providing a quantity of cellulose ester particulates; and (b) introducing at least a portion of the quantity of particulates directly into an extrusion process comprising a vented extruder to form a melt composition. The providing step (a) can comprise particulating a cellulose ester material to provide the quantity of particulates. The vented extruder can comprise a single screw extruder. For the single extruder, the quantity of cellulose ester particulates can have a moisture content of not more than 4, or not more than 3, or not more than 2, or not more than 1 weight % whenintroduced (b). The vented extruder can comprise a twin-screw extruder. For the twin-screw extruder, the quantity of cellulose ester particulates can have a moisture content of not more than 5, or not more than 4, or not more than 3 weight % when introduced (b).

[0127] The process according to this first aspect can be carried out wherein the quantity of cellulose ester particulates are not subjected to a drying step between the providing (a) and introducing (b). The moisture content of the melt composition can be reduced by at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, at least 98%, at least 99%, or at least 99.9% within the vented extruder. The moisture content of the melt composition can be reduced to not more than 2000 ppm, not more than 1500 ppm, not more than 1200 ppm, not more than 1000 ppm, or not more than 800 ppm within the vented extruder. The vented extruder can comprise an inlet, outlet (i.e., exit of the extruder), and at least one vent port. The vent port can be located in a position closer to the outlet than to the inlet. The twin-screw extruder can comprise at least a first vent port and a second vent port upstream of the first vent port. The first vent port can be located closer to the outlet than to the inlet, and the second vent port can be located closer to the inlet than to the outlet. A vapor exhaust stream can be removed from the melt composition through the at least one vent port. The vapor exhaust stream can comprise water and a plasticizer.

[0128] The process can further comprise separating the water and the plasticizer to recover a water-enriched liquid stream and a plasticizer-enriched liquid stream (any known separation methods may be used). The separating can comprise a refining process. The refining process can comprise a filtration process (e.g., standard filtration or selective membrane) and / or a distillation process. At least a portion of the plasticizer-enriched stream can be used as a plasticizer in a cellulose ester particulating process. At least a portion of the plasticizer-enriched stream can be combined with another plasticizer stream before being introducing to the particulating process.

[0129] In a second aspect, a method of extruding a cellulose ester composition is provided, the method comprising: (a) providing a cellulose estermaterial; and (b) introducing at least a portion of the cellulose ester material directly into an extrusion process comprising a twin-screw vented extruder to form a melt composition. This method can further comprise combining the cellulose ester material with a plasticizer. The providing step (a) can comprise particulating the cellulose ester material to form a quantity of particulates that are introduced into the extrusion process (b). The cellulose ester material can have a moisture content of not more than 5 weight %. The method according to this second aspect can be carried out wherein the cellulose ester material is not subjected to a drying step between the providing (a) and introducing (b). The moisture content of the melt composition can be reduced by at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, at least 98%, at least 99%, or at least 99.9% within the vented extruder. The moisture content of the melt composition can be reduced to not more than 2000 ppm, not more than 1500 ppm, not more than 1200 ppm, not more than 1000 ppm, or not more than 800 ppm within the vented extruder. The twin-screw vented extruder can comprise an inlet, outlet (i.e., exit of the extruder), and at least one vent port located in a position closer to the outlet than to the inlet. The twin- screw vented extruder can comprise a gear pump configured to maintain constant output through a shaping die at the extruder outlet. The twin-screw vented extruder can comprise at least a first vent port and a second vent port upstream of the first vent port. The first vent port can be located closer to the outlet than to the inlet, and the second vent port can be located closer to the inlet than to the outlet.

[0130] In a third aspect, an extrusion process is provided that comprises: (a) providing a quantity of bio-based polymer particulates; (b) introducing at least a portion of the quantity of particulates into an extruder barrel without drying the at least a portion of the quantity of particulates, to thereby form a melt composition; and (c) extruding the melt composition. The extruder barrel can comprise a vented extruder barrel that comprises an inlet, outlet, and at least one vent port located closer to the outlet than to the inlet (upper1 / 2, 1 / 3, %, etc. of extruder barrel). The moisture content of the melt composition can be reduced by at least 50%, at least 60%, at least 70%, at least 80%, at least 90%,at least 95%, at least 98%, at least 99%, or at least 99.9% within the vented extruder. The moisture content of the melt composition can be reduced to not more than 2000 ppm, not more than 1500 ppm, not more than 1200 ppm, not more than 1000 ppm, or not more than 800 ppm within the vented extruder. The vented extruder can comprise a single screw extruder. The vented extruder can be a twin-screw extruder. The twin-screw extruder can comprise at least a first vent port and a second vent port upstream of the first vent port. The first vent port can be located closer to the outlet than to the inlet, and the second vent port can be located closer to the inlet than to the outlet.

[0131] In a fourth aspect, an extrusion process is provided that comprises: (a) introducing a bio-based polymer material into a twin-screw vented extruder barrel without drying the bio-based polymer material, to thereby form a melt composition; and (b) extruding the melt composition. The moisture content of the melt composition can be reduced by at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, at least 98%, at least 99%, or at least 99.9% within the vented extruder. The moisture content of the melt composition can be reduced to not more than 2000 ppm, not more than 1500 ppm, not more than 1200 ppm, not more than 1000 ppm, or not more than 800 ppm within the vented extruder. The twin-screw extruder can comprise at least a first vent port and a second vent port upstream of the first vent port. The first vent port can be located closer to the outlet than to the inlet, and the second vent port can be located closer to the inlet than to the outlet.

[0132] In a fifth aspect, a foamed extrusion process is provided that comprises: (a) introducing a bio-based polymer material into a vented extruder to form a melt composition; (b) introducing at least a portion of the melt composition into an injection extruder; and (c) injecting a blowing agent into the melt composition via the injection extruder, thereby forming a foamed composition. The bio-based polymer material can comprise a polymer selected from the group consisting of aliphatic polyesters, aliphatic aromatic polyesters, cellulose esters, and combinations or blends thereof. The bio-based polymer material can be in the form of pellets, flakes, powders, granules, and / or fibers.

[0133] The method according to this fifth aspect can further comprise introducing the foamed composition into a cooling unit to thereby lower the temperature of the foamed composition. The cooling unit can comprise a cooling extruder or cooling mixer unit. The cooling unit can lower the temperature of the foamed composition by at least 10 C, at least 20 C, at least 30 C, at least 40 C, at least 50 C, at least 60 C, at least 70 C, or at least 80 C. (or in a range from 10-100 C, or 20-80 C). The moisture content of the melt composition can be reduced by at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, at least 98%, at least 99%, or at least 99.9% within the vented extruder. The moisture content of the melt composition can be reduced to not more than 2000 ppm, not more than 1500 ppm, not more than 1200 ppm, not more than 1000 ppm, or not more than 800 ppm within the vented extruder.

[0134] The vented extruder can comprise an inlet, outlet, and at least one vent port located in a position closer to the outlet than to the inlet. The injection extruder can comprise an inlet, outlet, and at least one injection port. The injection port can be located at a position closer to the inlet than to the outlet.CLAIMS NOT LIMITED TO DISCLOSED EMBODIMENTS

[0135] The preferred forms of the invention described above are to be used as illustration only and should not be used in a limiting sense to interpret the scope of the present invention. Modifications to the exemplary embodiments, set forth above, could be readily made by those skilled in the art without departing from the spirit of the present invention.

[0136] The inventors hereby state their intent to rely on the Doctrine of Equivalents to determine and assess the reasonably fair scope of the present invention as it pertains to any apparatus not materially departing from but outside the literal scope of the invention as set forth in the following claims.

Claims

CLAIMSWhat is claimed is:1 . A method of extruding a cellulose ester composition, the method comprising:(a) providing a cellulose ester material; and(b) introducing at least a portion of the cellulose ester material directly into an extrusion process comprising a vented extruder to form a melt composition.

2. The method according to claim 1 , wherein the melt composition has a moisture content at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, at least 98%, at least 99%, or at least 99.9% less than the moisture content of the cellulose ester material.

3. The method according to claim 1 or 2, wherein the vented extruder comprises an inlet, an outlet, and at least one vent port; and wherein a vapor exhaust stream is removed from the melt composition through the at least one vent port.

4. The method according to any one of claims 1 to 3, wherein the vented extruder comprises a single screw extruder comprising an inlet, an outlet, and at least one vent port located in a position closer to the extruder outlet than to the extruder inlet.

5. The method according to claim 4, wherein the moisture content of the melt composition is reduced to not more than 2000 ppm, not more than 1500 ppm, or not more than 1000 ppm within the vented extruder.

6. The method according to any one of claims 1 to 3, wherein the vented extruder is a twin-screw extruder.

7. The method according to claim 6, wherein the twin-screw extruder comprises an inlet, an outlet, a first vent port and a second vent port upstream of the first vent port.

8. The method according to claim 7, wherein first vent port is located closer to the outlet than to the inlet, and wherein the second vent port is located closer to the inlet than to the outlet.

9. The method according to any one of claims 6 to 8, wherein the moisture content of the melt composition is reduced to not more than 1200 ppm, not more than 1000 ppm, or not more than 800 ppm within the vented extruder.

10. The method according to any one of claims 1 to 9, wherein the cellulose ester material has a moisture content of 0.5 to 5, or 0.6 to 5, or 1 to 5 weight % when introduced in step (b).1 1 . The method according to any one of claims 1 to 10, wherein the cellulose ester material is provided in the form of a quantity of particulates.

12. The method according to claim 1 1 , wherein the quantity of cellulose ester particulates are not subjected to a drying step between the providing (a) and introducing (b).

13. The method according to any one of claims 1 to 12, wherein a vapor exhaust stream is removed from the melt composition through the at least one vent port and wherein the vapor exhaust stream comprises water and a plasticizer.

14. The method according to claim 13, further comprising separating the water and the plasticizer to recover a water-enriched liquid stream and a plasticizer-enriched liquid stream.

15. The method according to any one of claims 1 to 14, wherein at least one vent port is under vacuum.

16. The method according to any one of claims 1 to 15, wherein the melt composition maintains a molecular weight (Mw) within at least 80%, at least 90%, at least 95%, at least 96%, or at least 97% of the Mw of the cellulose ester material.

17. A foamed extrusion process comprising:(a) introducing at least a portion of the melt composition formed according to any one of claims 1 to 16 into an injection extruder; and(b) injecting a blowing agent into the melt composition via the injection extruder, thereby forming a foamed composition.

18. The process according to claim 17, further comprising introducing the foamed composition into a cooling unit to thereby lower the temperature of the foamed composition.

19. The process according to claim 18, wherein the cooling unit lowers the temperature of the foamed composition by at least 10 C, at least 20 C, at least 30 C, at least 40 C, at least 50 C, at least 60 C, at least 70 C, or at least 80 C.

20. A process for producing a foamed sheet comprising:(a) directing at least a portion of the foamed composition formed according to any one of claims 17 to 19 through a die and out of a die head to provide a foamed extrudate; and(b) processing the foamed extrudate in a sheet forming section to form a foamed sheet.21 . The process according to claim 20, wherein the foamed sheet is formed by a process that comprises:(i) forming a melt composition in a vented extruder,(ii) forming a foamed composition by introducing the melt composition into an injection extruder and injecting a gas into the injection extruder via a gas injection port; and(iii) cooling the foamed composition by introducing the foamed composition into a cooling unit chosen from an extruder or a melt cooler.

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