Methods for removal of water from particulates

Abstract

A method for efficient removal of water from cellulose ester particulates, the method comprising: (a) introducing a composition comprising cellulose ester particulates into a dryer unit, wherein the cellulose ester particulates have a D90 of 0.5 mm to 7.0 mm, an average surface area-to-volume (SA / V) ratio of greater than 1 mm-1 to 3 mm-1, a gradient tube density of less than 1.35 g / cc; and (b) passing a drying gas for a period of time T across at least a portion of the cellulose ester particulates to form dried cellulose ester particulates, wherein the drying gas has a temperature of from 30°C to 60°C below the Tg of the cellulose ester.

Description

METHODS FOR REMOVAL OF WATER FROM PARTICULATESTECHNICAL FIELD

[0001] This invention relates to methods for the efficient removal of water from cellulose ester particulates. More particularly this invention relates to methods for the efficient removal of water from cellulose ester particulates in order to reduce drying time and energy.BACKGROUND

[0002] Many consumer 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 articles is polystyrene, which can be used to make foamed articles. 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 consumer articles, as well as viable compositions, methods, and systems for producing such articles.

[0003] During sheet and article production processes, pellets or other particulates are introduced into an extrusion process, where they are melted and extruded. However, certain pellet materials will undesirably absorb moisture from the environment and must be dried before being introduced into the extrusion process. Otherwise, this extra moisture during the extrusion process may result in defects in the sheets and articles. Extra moisture in the process may also cause flow issues, molecular weight degradation, hazy extrudate, and voids to form in the article. Further, a drying step can be time and energy intensive and slow production down. Accelerating drying is desired for any polymer product as the drying process can have a direct impact on output rate and economics of the polymer processing line. For foam extrusion, excessive water can act to alter the rheology of the product, which can lead to poor melt strength, open cells, large cells, and poor thickness control.

[0004] Accordingly, it may be desirable to find improved drying processes to reduce drying time and energy, as well as improved compositions having less moisture for use in manufacturing biodegradable or compostable food packaging articles.SUMMARY

[0005] In one or more embodiments herein, provided are methods for efficient removal of water from cellulose ester particulates. The methods comprise (a) introducing a composition comprising cellulose ester particulates into a dryer unit, wherein the cellulose ester particulates have a D90 of 0.5 mm to 7.0 mm, an average surface area-to-volume (SA / V) ratio of greater than 1 mm'1to 3 mm1, a gradient tube density of less than 1.35 g / cc, and wherein the cellulose ester particulates are substantially spherical in shape or substantially cylindrical in shape; and (b) passing a drying gas for a period of time T across at least a portion of the cellulose ester particulates to form dried cellulose ester particulates, wherein the drying gas has a temperature of from 30°C to 60°C below the Tg of the composition.

[0006] In one or more embodiments herein, provided are methods for efficient removal of water from cellulose ester particulates. The methods comprise (a) introducing a composition comprising cellulose ester particulates into a dryer unit, wherein the cellulose ester particulates have a D90 of 0.5 mm to 7.0 mm, an average surface area-to-volume (SA / V) ratio of greater than 1 mm'1to 3 mm1, a gradient tube density of less than 1.25 g / cc, and wherein the cellulose ester particulates are hollowed; and (b) passing a drying gas for a period of time T across at least a portion of the cellulose ester particulates to form dried cellulose ester particulates, wherein the drying gas has a temperature of from 30°C to 60°C below the Tg of the composition.

[0007] In one or more embodiments herein, provided are particulate compositions. The particulate compositions comprise dried cellulose ester particulates, wherein the dried cellulose ester particulates have a D90 of 0.5 mm to 7.0 mm, an average surface area-to-volume (SA / V) ratio of greater than 1 mm'1to 3 mm1, a gradient tube density of less than 1.25 g / cc; wherein the dried cellulose ester particulates are hollowed; andwherein the dried cellulose ester particulates have a moisture content of less than 1%, by weight.

[0008] In one or more embodiments herein, provided are particulate compositions. The particulate compositions comprise dried cellulose ester particulates, wherein the dried cellulose ester particulates have a D90 of 0.5 mm to 7.0 mm, an average surface area- to -volume (SA / V) ratio of greater than 1 mm'1to 3 mm1, a gradient tube density of less than 1.35 g / cc; wherein the dried cellulose ester particulates are substantially spherical in shape or substantially cylindrical in shape; and wherein the dried cellulose ester particulates have a moisture content of less than 1%, by weight.

[0009] In one or more embodiments herein, the composition further comprises one or more additional particulates formed from a biobased polymer. In one or more embodiments herein, the biobased polymer is selected from the group consisting of 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 ethers, starch (including modified starches), and combinations thereof.

[0010] In one or more embodiments herein, the cellulose ester particulates or dried cellulose ester particulates comprise cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, or combinations thereof. In one or more embodiments herein, the cellulose ester particulates or dried cellulose ester particulates comprise cellulose acetate having a degree of substitution DSAc of from 1.8 to 2.7. In one or more embodiments herein, the cellulose ester particulates or dried cellulose ester particulates comprise a cellulose acetate having an average degree of substitution for the unsubstituted hydroxyl group (DSOH) that is from 0 to 1.2. In one or more embodiments herein, the cellulose ester particulates or dried cellulose ester particulates comprise a cellulose acetate propionate (CAP) having an average degree of substitution for the hydroxyl substituents (DSOH) that is from 0.3 to 1.2, an average degree ofsubstitution for the acetyl substituents (DSAC) that is from 0 to 0.5, and an average degree of substitution for the propionyl substituents (DSPr) from 1.8 to 2.7.

[0011] In one or more embodiments herein, the cellulose ester particulates comprise a cellulose acetate having a glass transition temperature (Tg) of from 160 °C to 220 °C. In one or more embodiments herein, the cellulose ester particulates comprise a cellulose acetate propionate (CAP) having a glass transition temperature (Tg) of from 120 °C to 170 °C. In one or more embodiments herein, the dried cellulose ester particulates comprise a cellulose acetate, wherein the dried cellulose ester particulates have a glass transition temperature (Tg) of from 80 °C to 150 °C. In one or more embodiments herein, the dried cellulose ester particulates comprise a cellulose acetate propionate (CAP), wherein the dried cellulose ester particulates have a glass transition temperature (Tg) of from 70 °C to 110 °C.

[0012] In one or more embodiments herein, the composition or particulate composition further comprises from 5 to 40 wt.%, based on the total weight of the composition, of a plasticizer. In one or more embodiments herein, the plasticizer is selected from the group consisting of triacetin, triethyl citrate, acetyl triethyl citrate, dioctyl adipate, bis(2-ethylhexyl)-l,4-benzenedicarboxylate, polyethylene glycol, benzoate containing plasticizers, epoxides, adipates, and combinations thereof.

[0013] In one or more embodiments herein, the composition or particulate composition further comprises from 0.2 to 5 wt.%, based on the total weight of the composition, of a lubricant. In one or more embodiments herein, the lubricant is selected from the group consisting of fatty acids, fatty acid amides, fatty acid esters, metal salts of fatty acids, biodegradable waxes, oils, and combinations thereof.

[0014] Additional features and advantages of the embodiments will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the embodiments described herein, including the detailed description which follows, the claims, as well as the appended drawings. It is to be understood that both the foregoing and the following description describe various embodiments and are intended to provide anoverview or framework for understanding the nature and character of the claimed subject matter. The accompanying drawings are included to provide a further understanding of the various embodiments and are incorporated into and constitute a part of this specification. The drawings illustrate the various embodiments described herein, and together with the description serve to explain the principles and operations of the claimed subject matter.BRIEF DESCRIPTION OF THE DRAWINGS

[0015] FIG. 1 is a schematic diagram illustrating a biodegradable article forming process;

[0016] FIG. 2 is a schematic diagram illustrating another biodegradable article forming process;

[0017] FIG. 3 is a schematic diagram illustrating a drying process;

[0018] FIG. 4 is a schematic diagram illustrating a drying gas processing and recycling process; and

[0019] FIG. 5 is a schematic diagram illustrating a polymer pellet drying apparatus.DETAILED DESCRIPTIONDefinitions

[0020] 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.

[0021] As used herein, the terms “a,” “an,” and “the” mean one or more.

[0022] 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.

[0023] 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.

[0024] 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 different degrees of biodegradability, depending on the specific conditions to which it is exposed. The term “disintegrable” 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.

[0025] 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.

[0026] 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 drymass) 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.

[0027] In order to be considered “biodegradable” under soil composting conditions according the OK biodegradable SOIL conformity mark of Vingotte and the DIN Gepriift 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 a plateau has been reached for both the reference and test item. The maximum test duration for biodegradability under soil compositing conditions is 2 years.

[0028] 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.

[0029] Embodiments are generally directed to methods for efficient removal of water from compositions containing cellulose ester particulates, and the resulting particulate compositions formed thereof. The particulate compositions may be used in forming pellets, sheets (e.g., foam sheets), and articles. It is noted, however, that this is merely an illustrative implementation of the embodiments disclosed herein.

[0030] In embodiments herein are methods for efficient removal of water from cellulose ester particulates are described herein. The methods comprise (a) introducing a composition comprising cellulose ester particulates into a dryer unit; and (b) passing a drying gas for a period of time T across at least a portion of the cellulose ester particulates to form dried cellulose ester particulates. Also in embodiments herein are particulate compositions formed according to the methods described herein. The period of time T will depend on the desired level of moisture to be removed (e.g., a moisturecontent of less than 1 wt.%), the composition being treated, the drying conditions employed, as well as environmental conditions.

[0031] As shown in FIG. 1 and FIG. 2, raw materials may be introduced to a biobased 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 biobased polymer material comprises one or more cellulose esters. The one or more cellulose esters may comprise cellulose acetates, cellulose acetate propionates, or cellulose acetate butyrates, and optionally, one or more additional biobased polymers. 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 biobased cellulose ester polymer, such as a cellulose acetate, cellulose acetate propionate, or cellulose acetate butyrate polymer.

[0032] The bio-based polymer material may then be introduced into a compounding process, in which the bio-based polymer materials may be mixed with plasticizer, and optionally one or more other additives, and formed into a compounded material comprising plasticized biobased 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), drying agent(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.

[0033] The compounding process may include a particulating process. The particulating process may generally comprise mixing the cellulose ester and optionally, one or more other bio-based polymer materials, 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. 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.

[0034] In one embodiment or in combination with any other embodiment mentioned herein, the plasticizer and other additive(s) may be mixed with cellulose ester along and optionally, one or more other bio-based polymers by conventional melt compounding techniques, which involve combining the polymer 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 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 material fed to the foam sheet production process can be in any physical shape (e.g., pellets, powders, granules, fibers) in accordance with some embodiments. The term “compounded material” means cellulose ester and optionally, along with one or more other bio-based polymer materials formed during the compounding process, which may include a mixture of polymers, plasticizer, and other additives. Further such compounded material may be in the form of a molten mixture or a particulate material (e.g., pellets, powders, granules, fibers, etc.).

[0035] The particulates (as used herein refer to cellulose ester and optionally, along with one or more bio-based polymers) may advantageously possess one or more characteristics that reduce the overall drying time, drying energy, and / or drying cost for drying the particulates, as compared to traditional particulates, before introduction into a sheet forming process. Such characteristics may include, but are not limited to, the surface area-to-volume ratio (SA / V) of the particulates, particulate size, particulate shape (geometries), and / or density of the particulates. Such characteristics may result from the compounding or particulating processes described above or another suitable process.

[0036] In one embodiment or in combination with any other embodiment mentioned herein, the quantity of particulates have an average surface area-to-volume (SA / V) ratio greater than traditional particulates, thereby providing greater surface area for drying air to contact the particulates. For example, the quantity of particulates may have an average surface area-to-volume (SA / V) ratio of from greater than 1.0 mm'1, greater than 1.5 mm1, greater than 2.0 mm'1to less than 6.0 mm1, less than 5.0 mm'1, less than 4.0 mm1, or less than 3.0 mm1. In some embodiments, the quantity of particulates may have an average surface area-to-volume (SA / V) ratio of 1.0 mm'1to 6.0 mm'1, 1.0 mm'1to 4.0 mm'1, or 1.0 mm 'to 3.0 mm1. In other embodiments, the particulates may have an average surface area-to-volume (SA / V) ratio of greater than 1 or 1.25 mm'1to 3.0 or 2.5 mm1.

[0037] In one embodiment or in combination with any other embodiment mentioned herein, the quantity of particulates have a D90 value (i.e., where ninety percent of the quantity has a smaller diameter and ten percent has a larger diameter) lower than traditional particulates, thereby providing a greater SA / V for drying the particulates. For example, the quantity of particulates may have a D90 of less than 10 mm, less than 8 mm, less than 7 mm, less than 6.5 mm, less than 5 mm, less than 4 mm, less than 3 mm, or less than 2 mm. The quantity of particulates may have a D90 of at least 0.5 mm, at least 0.6 mm, at least 0.7 mm, at least 0.8 mm, at least 0.9 mm, at least 1.0 mm, at least 1.1 mm, at least 1.2 mm, at least 1.3 mm, at least 1.4 mm, or at least 1.5 mm. All individual values and subranges are disclosed herein. For example, insome embodiments, the particulates may have a D90 of from 0.5 mm, 1.5 mm, or 2.5 mm to 7.5 to 7.0 mm. In other embodiments, the particulates may have a D90 of from 0.5 mm to 7.0 mm. It should be understood that although D90 may refer to diameters of generally spherical particulates, these values may also refer to diameters of other geometries, such as the diameter of the circular base of cylindrical particulates.

[0038] In one embodiment or in combination with any other embodiment mentioned herein, the quantity of particulates have geometries that have increased surface area and / or decreased density as compared to traditional particulates. For example, the particulates may comprise hollowed structures (i.e., having pores, space, holes, or one or more channels formed therethrough, and includes foamed structures) and / or irregular geometries (i.e., non-uniform diameter). Due to the hollowed structures, the quantity of particulates may have a gradient tube density that is less than the density of the polymer composition. In some embodiments, the quantity of particulates may have a gradient tube density of not more than (alternatively, less than) 1.35 g / cc, 1.3 g / cc, 1.25 g / cc, 1.2 g / cc, or 1.15 g / cc. In some embodiments, the quantity of particulates may have a gradient tube density of 0.3 g / cc to 1.35 g / cc, 0.5 g / cc to 1.35 g / cc, or 0.7 g / cc to 1.35 g / cc. The irregular geometries may comprise, for example, trident or star-shaped structures.

[0039] In some embodiments, the particulates are substantially spherical or cylindrical in shape. In other embodiments, the particulates are substantially spherical or cylindrical in shape, have a D90 of 0.5 mm to 7.0 mm, an average surface area-to- volume (SA / V) ratio of greater than 1 or 1.15 mm1to 3 or 2.5 mm1, and a gradient tube density of less than 1.35 g / cc (alternatively, from 0.75, 1.0, 1.1, 1.2, or 1.25 to less than 1.35 g / cc). In further embodiments, the particulates are hollowed, have a D90 of 0.5, 2.5, or 4.5 mm to 7.0 mm, an average surface area-to-volume (SA / V) ratio of greater than 1 mm'1to 3 mm1or 2.5 mm1, and a gradient tube density of less than 1.25 g / cc (alternatively, from 0.95 to less than 1.25 g / cc or from 1.0 to 1.2 g / cc).

[0040] In one embodiment or in combination with any other embodiment mentioned herein, the particulates are subjected to a drying process before beingintroduced to the sheet forming process, such as illustrated in FIG. 3. The drying process may comprise, for example, one or more drying units, such as a hot air dryer and / or a desiccant drying system. However, in some embodiments, the quantity of particulates are not introduced into a desiccant drying system as part of the drying process. It should be understood that the hot air drying unit may utilize a drying gas other than air, so long as at least a portion of the moisture content may be removed from the particulates and become entrained in the drying gas.

[0041] In one embodiment or in combination with any other embodiment mentioned herein, the quantity of particulates are introduced into a hot air drying unit. A drying gas is then passed across and / or through the particulates, thereby removing moisture from the particulates that becomes entrained in the drying gas stream, which is flowed out of the drying unit. The drying gas may comprise air, nitrogen, argon, helium, and / or other inert gas. In some embodiments, the drying is selected from the group consisting of air, nitrogen, argon, helium, and combinations thereof. Advantageously, embodiments herein may utilize a lower drying gas temperature than traditional systems, thereby reducing the costs associated with the drying process. For example, the drying gas may be introduced at a temperature of from 60 °C to 30 °C, or 50 °C to 40 °C, below the glass transition temperature (Tg) of the composition. However, in some embodiments, the drying gas may be introduced at a temperature of at least 50 °C or 55 °C and / or not more than 100 °C, 90 °C, or 80° C.

[0042] In one embodiment or in combination with any other embodiment mentioned herein, the dew point of the drying gas may be reduced before being introduced into the hot air drying unit. This may be accomplished, for example, by dehumidifying at least a portion of the drying gas before introducing the gas into the drying unit. In some embodiments, the drying gas introduced into the drying unit has a dew point of not more than 0 °F, not more than -20 °F, or not more than -40 °F.

[0043] In one embodiment or in combination with any other embodiment mentioned herein, the drying unit is a hot air drying unit, a desiccant drying unit, or a combination there of. In some embodiments, the drying until comprises a desiccantdrying unit downstream of the hot air drying unit. In particular, in embodiments that do not utilize a dew point reduction process for the drying gas (i.e., do not de-humidify the drying gas), a downstream desiccant drying system may be necessary to achieve sufficient drying of the particulates.

[0044] In one embodiment or in combination with any other embodiment mentioned herein, the drying process (comprising the hot air drying unit and / or desiccant drying system) are capable of reducing the moisture content of dried particulates to less than 1% by weight after a period of time T of 4 (alternatively, 3.5 or 3) hours. For example, the hot air drying unit may be utilized to reduce the moisture content of the particulates to less than 1% by weight, and the downstream desiccant drying system may be utilized to further reduce the moisture content to even lower levels.

[0045] Referring to FIG. 4, in one embodiment or in combination with any other embodiment mentioned herein, the hot moist drying gas exiting the drying unit may be processed to remove (and optionally collect) volatiles and / or particulate matter (e.g., dust, fines, etc.) becoming entrained therein, which allows the drying gas to be recirculated for use in the drying system. An exemplary system for processing the vapor stream is depicted in FIG. 4. The moist drying gas is fed through an inlet, where it may be optionally first subjected to particulate filtration to remove dust and other fine particulate matter. The drying gas at the inlet may have a temperature of 40 °C to 80 °C, or 50 °C to 70 °C. The (optionally filtered) drying gas is then cooled and at least partially condensed. For example, the drying gas may be passed over a cooling coil, or other heat exchanger, thereby condensing at least a portion of the volatile components from the drying gas. The drying gas and any condensed liquid can then be passed to a condensate collection zone, which may include one or more steps operable to remove the condensate from the drying gas. For example, a first step may include contacting the drying gas with baffles or other surfaces, upon which the condensate may form and flow downward into a catch basin positioned at the bottom of the processing system. Other steps may include redirection (e.g., upward) and velocity change of the drying gas stream, which can cause at least a portion of the entrained condensate to separatefrom the drying gas and fall for collection and recovery in the catch basin. Additionally, or alternatively, a second cooling step may be utilized to further condense at least a portion of the volatile components remaining in the drying gas stream. For example, in some embodiments, the first cooling step may condense 50-80% of the volatile components in the drying gas stream, while the second cooling step may condense 20- 50% of the volatile components in the drying gas stream. Finally, the drying gas may be optionally subjected to further filtration, including particulate filtration and / or scrubbing filtration to recovery any remaining condensate in the drying gas before the drying gas is directed through the outlet. The temperature of the drying gas stream exiting the system may be 0 °C to 10 °C lower, or 1 °C to 5 °C lower than the temperature of the vapor stream at the inlet. In some embodiments, the recovered condensate can be optionally filtered and stored or recycled for further use. For example, in some embodiments, the condensate comprises a blowing agent and / or plasticizer that was volatilized during drying, and the condensed blowing agent and / or plasticizer can be recycled back for use in the compounding process described above.

[0046] The particulates, 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 / non-hollowed) 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, buildup resistant additives, stabilizers, physical blowing agent(s), chemical blowing agent(s) (and / or precursors), nucleating agent(s), pigment(s), filler(s), and / or other additive(s).

[0047] 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 whichsolid 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), pigment(s), filler(s), and / or other additive(s).

[0048] 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 polymer-based 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.

[0049] One or more additive(s) may be introduced to the melt composition while in the extruder. For example, one or more physical blowing agent(s) may be added to the melt composition by injecting the additive(s) into the composition being conveyed within the extruder barrel.

[0050] In one embodiment or in combination with any other embodiment mentioned herein, the extrusion zone may comprise a primary extrusion vessel and 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 primary extrusion vessel and at least partially melted as it is conveyed through the extruder barrel, as described above, to thereby produce the melt composition. The melt composition exiting the primary extrusion vessel may have a temperature from about 220° C to about 240° C. One or more additives, such as blowing agent(s), may be added to the melt composition as it is conveyed through the primary extrusion vessel.

[0051] The melt composition from the primary extrusion vessel may also be introduced into a cooling vessel. 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 a polymer-based (e.g., cellulose ester based) extrudate, which may be further processed in the sheet forming section of the 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.

[0052] The sheet forming section may include any of a variety of systems and processes for shaping the extrudate into sheets of 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.

[0053] Referring again to FIG. 1 and FIG. 2, the sheets produced by the sheet production process may be used to form articles (e.g. , rigid articles, hollowed or foamed articles, etc.), which are described in greater detail below. Such articles are particularly useful in the food service industry. Exemplary articles include meat trays, hinged containers, bowls, and egg cartons. 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.).

[0054] 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). In one embodiment or in combination with any other embodiment mentioned herein, the bio-based polymer comprises a cellulose ester. In one embodiment or in combination with any other embodiment mentioned herein, the composition comprises one or more one or more drying enhancers, such as waxes and / or fatty acid salts.

[0055] Additional details of the composition components, including biodegradable polymers (e.g., cellulose esters) and other additives, are provided below.Cellulose Ester

[0056] 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:wherein R 1 , R 2 , and R 3 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.

[0057] 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 anhydroglucoserings. 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 of phenol / 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.

[0058] 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.

[0059] 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.

[0060] 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 LiCl / DMAc or LiCl / NMP.

[0061] 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.

[0062] 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. In some embodiments, the cellulose ester particulates comprise a cellulose acetate resin, a cellulose acetate propionate resin, a cellulose acetate butyrate resin, or combinations thereof.

[0063] In one or more embodiments herein, the cellulose ester particulates or dried cellulose ester particulates comprise a cellulose acetate having an average degree of substitution for the unsubstituted hydroxyl group (DSOH) that is from 0 to 1.2 and / or an average degree of substitution for the acetyl substituent (DS AC) that is from 1.8 to2.7. All individual values and subranges are included and disclosed herein. For example, in some embodiments, the average degree of substitution for the unsubstituted hydroxyl group (DSOH) that is from 0.1 to 1.0, 0.1 to 0.75, 0.1 to 0.6, or 0.2 to 0.5 and / or the average degree of substitution for the acetyl substituent (DSAC) that is froml.8 to 2.7, 1.8 to 2.6, 1.8 to 2.5, 2.0 to 2.7 or 2.2 to 2.7.

[0064] In one or more embodiments herein, the cellulose ester particulates or dried cellulose ester particulates comprise a cellulose acetate propionate (CAP) having an average degree of substitution for the hydroxyl substituents (DSOH) that is from 0.3 to 1.2, an average degree of substitution for the acetyl substituents (DSAC) that is from 0 to 0.5, and an average degree of substitution for the propionyl substituents (DSPr) from1.8 to 2.7. All individual values and subranges are included and disclosed herein. For example, in some embodiments, the average degree of substitution for the hydroxyl substituents (DSOH) that is from 0.3 to 1.1, 0.4 to 1.1, or 0.5 to 1.0, the average degree of substitution for the acetyl substituents (DSAC) that is from 0 to 0.4, 0 to 0.3, 0 to 0.25, or 0 to 0.2, and the average degree of substitution for the propionyl substituents (DSPr) from 1.9 to 2.6 or 2.0 to 2.5. In other embodiments, the average degree of substitution for hydroxyl substituents that is from 0.5 to 1.0, the average degree of substitution for the acetyl substituents (DSAc) that is from 0 to 0.2, the average degree of substitution for the propionyl substituents (DSPr) that is from 2.0 to 2.5.

[0065] In one or more embodiments herein, the cellulose ester particulates comprise a cellulose acetate having a glass transition temperature (Tg) of from 160 °C to 220 °C. All individual values and subranges are included and disclosed herein. For example, in some embodiments, the Tg is from a lower limit of 160, 165, 170, 175, or 180 °C to an upper limit of 220, 215, 210, 205, 200, 195, or 190 °C (alternatively, from 170 to 210 °C, 170 to 205 °C, or 170 to 200 °C). In one or more embodiments herein, the dried cellulose ester particulates comprise cellulose acetate, wherein the dried cellulose ester particulates have a glass transition temperature (Tg) of from 80 °C to 150 °C. All individual values and subranges are included and disclosed herein. For example, in some embodiments, the Tg is from a lower limit of 80, 85, 90, 95, or 100 °C to an upper limit of 150, 145, 140, 135, or 130 °C (alternatively, from 85 to 145 °C, 90 to 140 °C, or 100 to 130 °C).

[0066] In one or more embodiments herein, the cellulose ester particulates comprise a cellulose acetate propionate (CAP) having a glass transition temperature (Tg) of from 120 °C to 170 °C. All individual values and subranges are included and disclosed herein. For example, in some embodiments, the Tg is from 120 °C to 165 °C or from 135 °C to 165 °C. In one or more embodiments herein, the dried cellulose ester particulates comprise cellulose acetate propionate (CAP), wherein the dried cellulose ester particulates have a glass transition temperature (Tg) of from 70 °C to 110 °C. All individual values and subranges are included and disclosed herein. For example, insome embodiments, the Tg is from 80 °C to 110 °C or from 85 °C to 110 °C. Tg may be measured by differential scanning calorimetry (DSC).

[0067] In one or more embodiments herein, the cellulose ester particulates comprise a cellulose acetate having a weight average molecular weight (Mw) from about 30,000 to about 300,000 g / mol, as measured by gel permeation chromatography (GPC), which is described below in the examples. In one embodiment or in combination with any other embodiment, the cellulose acetate composition comprises cellulose acetate having a weight average molecular weights (Mw) from a lower limit of 30,000, 50,000, 75,000, or 100,000 g / mol to an upper limit of 300,000, 250,000, 200,000, or 175,000 g / mol, as measured by gel permeation chromatography (GPC) using NMP as solvent and according to ASTM D6474.

[0068] 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.

[0069] 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.

[0070] In one embodiment or in combination with any other embodiment, the composition comprises cellulose ester in an amount from 50 to 99 wt%, or 60 to 99 wt%, or 70 to 99 wt%, or 75 to 99 wt%, from 75 to 95 wt%, or 75 to 90 wt%, all based on the total weight of the 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 hereinmay be comprised of a blend of two or cellulose esters having differing DSAcs; however, the blend may have a total DSAc of between 1.8 and 2.8.Plasticizer

[0071] In one embodiment or in combination with any other embodiment, the compositions described herein can comprise at least one viscosity reducing agent, such as a plasticizer. The plasticizer reduces the melt temperature, i.e., the Tg, and / or the melt viscosity of the polymer composition. Plasticizers may include glycerol triacetate (Triacetin), glycerol diacetate (Diacetin), dibutyl terephthalate, dimethyl phthalate, diethyl phthalate, poly(ethylene glycol) MW 200-600, dibutyl tartrate, di-2- methoxyethyl phthalate, ethyl o-benzoylbenzoate, triethylene glycol dipropionate, 1,2- epoxypropylphenyl ethylene glycol, l,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, epoxides such as soybean oil epoxide or the Paraplex™ plasticizer series, adipates, 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-l,3-diyl bis(2- methylpropanoate), bis(2-ethylhexyl)-l,4-benzenedicarboxylate, and polycaprolactones. In some embodiments, the plasticizer used herein may comprise a combination or mixture of two or more different types of plasticizers. Nevertheless, it should be understood that the viscosity reducing agents used in embodiments of the present invention may comprise various compositions that function to reduce polymer viscosity, such as plasticizers, lubricants, polymer blends, and the like.

[0072] 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, benzoate containing plasticizers, 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.

[0073] In one embodiment or in combination with any other embodiment, the plasticizer can be present in an amount sufficient to permit the 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 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 composition.

[0074] In one embodiment or in combination with any other embodiment, the plasticizer is a biodegradable plasticizer. Some examples of biodegradable plasticizers include triacetin, triethyl citrate, acetyl triethyl citrate, polyethylene glycol, bis(2- ethylhexyl)-l,4-benzenedicarboxylate, the benzoate containing plasticizers such as the Benzoflex™ plasticizer series, poly (alkyl succinates) such as poly (butyl succinate), polyethersulfones, adipate based plasticizers (dioctyl adipate), epoxides such assoybean oil or the Paraplex™ plasticizer series, adipates, sucrose based plasticizers, dibutyl sebacate, tributyrin, the Resoflex™ series of plasticizers, triphenyl phosphate, glycolates, polyethylene glycol, 2,2,4-trimethylpentane-l,3-diyl bis(2- methylpropanoate), and poly caprolactones. In some embodiments, the plasticizer is selected from the group consisting of triacetin, triethyl citrate, acetyl triethyl citrate, dioctyl adipate, bis(2-ethylhexyl)-l,4-benzenedicarboxylate, polyethylene glycol, benzoate containing plasticizers, epoxides, adipates, and combinations thereof.

[0075] In one embodiment or in combination with any other embodiment, the 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.

[0076] 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.

[0077] 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.

[0078] In one embodiment or in combination with any other embodiment, the composition comprises at least one plasticizer (as described herein) in an amount from 5 to 40 wt%, or 10 to 40 wt%, or 12 to 40 wt%, 13 to 40 wt%, or 15 to 40 wt%, or 17 to 40 wt%, or 5 to 35 wt%, or 10 to 35 wt%, or 13 to 35 wt%, or 15 to 35 wt%, or 17 to 35 wt%, or 5 to 30 wt%, or 10 to 30 wt%, or 13 to 30 wt%, or 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 17 to 25 wt%, all based on the total weight of the composition. In some embodiments, the composition further comprises from 5 to 40 wt.% (alternatively, 5 to 35 wt.%, 10 to 35 wt.%, 15 to 30 wt.% or 15 to 25 wt.%, based on the total weight of the composition, of a plasticizer.

[0079] 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.Biobased Polymers

[0080] In one embodiment or in combination with any other embodiment, the compositions described herein may further comprise one or more biobased polymer particulates (other than the cellulose ester). In one embodiment or in combination with any other embodiment, the other biobased polymer particulates is selected from the group consisting of polyhydroxyalkanoates (PH As and PHBs), polylactic acid (PL A), poly(gly colic 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 ethers, starch (including modified starches), and combinations thereof. In one embodiment or in combination with any other embodiment, the composition comprises cellulose ester particulates and one or more biobased polymer particulates.

[0081] In one embodiment or in combination with any other embodiment, the compositions described herein comprise cellulose ester blends with one or more biobased polymers that can enhance the melt strength and / or increase the elasticity of the composition. Particularly preferred biobased polymers include those that have high biodegradability, low Tg (e.g., below room temperature), and / or low modulus.

[0082] In one embodiment or in combination with any other embodiment, the biobased 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.

[0083] In one embodiment or in combination with any other embodiment, the biobased 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 biobased polymers can provide increased blow up ratios when combined with cellulose acetate propionate (CAP) and / or cellulose acetate butyrate (CAB).

[0084] In one embodiment or in combination with any other embodiment, the composition contains a biobased polymer (other than the cellulose ester) 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%, 1 to 20 wt%, or 5 to 20 wt.%, based on the composition. In one embodiment or in combination with any other embodiment, the composition contains a biobased polymer (other than the cellulose ester) 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%, 1 to 20 wt%, or 5 to 20 wt.%, based on the total amount of cellulose ester and biobased polymer. In one embodiment or in combination with any other embodiment, the at least one biobased 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 g / mol, 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

[0085] 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.

[0086] 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, physical nucleating 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.

[0087] Examples of suitable inorganic physical nucleating agents include, but are not limited to, minerals such as talc, CaCCh, 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 (Al(0H)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.

[0088] 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.

[0089] As noted above, suitable chemical nucleating agents (or precursors of in situ formed physical nucleating agents) are configured to decompose to create cellnucleation 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.

[0090] 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 the remaining 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.

[0091] 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 composition. In some embodiments, the nucleating agents used herein may comprise a combination or mixture of two or more different types of nucleating agents.

[0092] It is noted that the 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 material will remain as filler. Fillers can provide various properties to the resulting 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 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 material.Lubricants

[0093] Lubricants may be used to allow drying at higher temperatures without causing the pellets to stick together (agglomeration) thereby improving drying efficiency. The amount of lubricant used in the composition may be from a lower limit of 0.01 , 0.1, 0.2, 0.3, or 0.4 weight percent to an upper limit of 10, 8, 7.5, 5, or 3 weight percent based on the total weight percent of the composition. All individual values and subranges are included and disclosed herein. For example, in some embodiments, the composition further comprises from 0.2 or 0.3 to 5 or 3 wt.%, based on the total weight of the composition, of a lubricant. The optimum amount of additive used is determinedby factors well known in the art and considers variations in equipment, material, process conditions, and material film thickness.

[0094] Examples of suitable lubricants include fatty acid amides, such as erucamide and stearamide; metal salts of fatty acids such as calcium stearate and zinc stearate; fatty acids and its esters such as glycerol mono- and di-stearates, stearic acid, oleic acid, and palmitic acid; biodegradable waxes such as paraffin wax, carnauba wax, sugar cane; lamellar inorganic lubricants (e.g., boron nitride); oils such as mineral oil, soybean oil, canola oil etc. and acrylic copolymers (for example, PARALOID™ K175 available from Dow, Inc.). In some embodiments, the lubricant is selected from the group consisting of fatty acids, fatty acid amides, fatty acid esters, metal salts of fatty acids, biodegradable waxes, oils, and combinations thereof.Blowing Agents

[0095] A blowing agent refers to a physical or a chemical material (or combination of materials) that acts to expand nucleation sites. Blowing agents may 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.

[0096] 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 fora cellulose ester. 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.

[0097] Chemical blowing agents are materials that degrade or react to produce a gas (e.g., CO2 or 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.

[0098] 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.

[0099] 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 9.0wt%, 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 composition. In some embodiments, the blowing agents used herein may comprise a combination or mixture of two or more different types of blowing agents.Drying Enhancers

[0100] Drying enhancers refer to additives that may be included in the particulate compositions that reduce the energy required to remove moisture from the particulates (e.g., by utilizing lower drying temperatures or drying gas flow rates). Exemplary drying enhancers include, but are not limited to, waxes and / or fatty acid salts. The drying enhancers may be incorporated into the particulates by the compounding process and / or applied to the surface of the particulates.

[0101] In one embodiment or in combination with any of the embodiments mentioned herein, the drying enhancer(s) may be present at from 0.05 to 5.0 wt%, or 0.1 to 4.0 wt%, or 0.5 to 3.0 wt%, or 1.0 to 2.0 wt%, all based on the total weight of the particulate composition. In one embodiment or in combination with any of the embodiments mentioned herein, the drying enhancer(s) may be included at a concentration of at least 0.01 wt%, at least 0.05 wt%, at least 0.1 wt%, at least 0.2 wt%, at least 0.3 wt%, at least 0.4 wt%, at least 0.5 wt%, at least 0.6 wt%, at least 0.7 wt%, at least 0.8 wt%, at least 0.9 wt%, or at a concentration of not more than 10 wt%, not more than 9 wt%, not more than 8 wt%, not more than 7 wt%, not more than 6 wt%, not more than 5 wt%, not more than 4 wt%, not more than 3 wt%, or not more than 2 wt%.Articles

[0102] Extruded sheets of 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 of the blowing agent in the form of a gas within the cellulose polymer melt. The structural material is cellulose ester based, with specificamounts of the compositional components of the structural material (e.g., cellulose ester, plasticizer, nucleating agents, 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.).

[0103] 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.

[0104] 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, or 500 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 pmto 350 m, 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.Foam Sheets, and / or Articles.

[0105] 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.

[0106] 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 subsubclass 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.

[0107] 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 noted that 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.

[0108] 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.

[0109] The compositions herein may 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 composition in an amount of 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 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.

[0110] In one embodiment or in combination with any other embodiment mentioned herein, the 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.

[0111] In one embodiment or in combination with any other embodiment mentioned herein, the composition further comprises a pigment. In one class of this embodiment, the pigment is a titanium dioxide, 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

[0112] The following specific examples are given to illustrate the process properties. The inventive and comparative examples along with the details of the formulations and results are provided in the Tables below. Table 1 - Cellulose Ester PropertiesGPC

[0113] 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: Tetrahydro furan 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.DSC

[0114] Samples are tested under ASTM D3418-21, The conditions for testing are as follows: The sample is equilibrated at 50 °C for 5 min to drive a moisture out. Then the sample was equilibrated at -5 °C for half a min and ramped to 155 °C at 50 °C / min. The sample is then cooled to -5 °C at 50 °C / min. This heating and cooling ramp steps were repeated for 3 and 2 more times respectively to make determine the glass transition temperature (°C) of the material. The equipment was a TA Instruments Q2000 using standard aluminum pan and helium or nitrogen as a purge gas.NMR

[0115] Nuclear Magnetic Resonance (NMR) yields signals from soluble cellulosic species proportional to their concentration in solution and the number of protons in each region. Degree of Substitution (DS) is the average mole ratio between the backbone cellulosic protons and protons assigned to the acetyl (or other ester of interest) peak(s). By comparing a normalized ratio of signal in these two regions, DS can be routinely calculated as a metric of functional group substitution on the cellulose backbone.Examples 1-5

[0116] All examples have a base composition of 20 wt.% of triacetin, 1.2 wt.% of stabilizers, and the balance Aventa™ FT1200 cellulose acetate. The composition was extruded on a 40mm Werner & Pfleiderer twin screw extruder to create differing pellet sizes all having a substantially right circular cylindrical shape. The materials were extruded at processing temperatures (80°C, 120°C, 180°C, 220°C, 220°C, 220°C, 220°C, 220°C ,235°C). Materials were extruded at 250rpms at a feed rate of lOOlbs per hour. The take up speed on the pelletizing unit was adjusted to set pellet diameter. Examples 1-3 were predried to a moisture level under 1000 ppm prior to extruding. Samples 4-5 were not predried prior to extrusion and had an initial moisture level of between 4000 and 5000 ppm. Materials were dried at 60°C with an air flow of 1 cfm / lb and samples were collected hourly to determine the moisture removal rate. Moisturewas determined via ASTM D-6869 Karl Fischer. As shown below, significant moisture removal can occur after just 4 hours with at least 75% moisture reduction.Table 2 - Moisture Removal Amount from Right Circular Cylinder PelletsTable 3 - % Moisture Change in Right Circular Cylinder PelletsExamples 6-9

[0117] All examples, except for Example 8, have a base composition of 20 wt.% of triacetin, 1.2 wt.% of stabilizers, and the balance Aventa™ FT1200 cellulose acetate. In Example 8, 1 wt. of a foaming agent (Foamazol™ 73S) was added to the base composition. Substantially spherical pellets were made on a 2.5% Davis standard extruder using a Maag / Gala underwater pelletizer. The materials were extruded at temperatures of 210 to 260 °C for the zones and a die temperature of 310 to 340 °C. The die temperature was dependent on the pellet size. As the pellet size decreased, the die temperature had to be increased to minimize freezing off in the die from the waterflow across the surface. The water temperature for the underwater pelletizing unit was 80 to 90°C. Materials were dried at 60°C with an air flow of 1 cfm / lb and samples were collected hourly to determine the moisture removal rate. Moisture was determined via ASTM D-6869 Karl Fischer. Examples 6-9 were predried to a moisture level under 1000 ppm prior to extruding. As shown below, significant moisture removal can occur after just 4 hours with almost 80% or more moisture reduction.Table 4 - Moisture Removal Amount from Spherical PelletsTable 5 - % Moisture Change in Spherical PelletsExamples 10-12

[0118] All examples have a base composition of 20 wt.% of triacetin, 1.2 wt.% of stabilizers, and the balance Aventa™ FT1200 cellulose acetate, which was mixed with a foaming agent (Foamazol™ 73S) added to the base composition, to create hollowed (or foamed) pellets of differing sizes. Examples 10 & 12 have 0.5 wt.% of foamingagent mixed with the base composition prior to extrusion. Example 11 has 1.0 wt.% of foaming agent mixed with the base composition prior to extrusion. Compositions were extruded at process temperatures of 150 to 220°C through a strand die and differing pellet sizes were made. The data shows a density reduction relative to the base resin and drying was evaluated. The examples are representative of regrind from a foam process, where some density reduction of the regrind will occur relative to the base resin. Examples 10-12 were predried to a moisture level under lOOOppm prior to extruding. Materials were dried at 60°C with an air flow of 1 cfm / lb and samples were collected hourly to determine the moisture removal rate. Moisture was determined via ASTM D-6869 Karl Fischer. As shown in the tables below, significant moisture removal can occur after just 2 hours, and at least 85% moisture reduction can occur after 4 hours.Table 6 - Moisture Removal Amount from Hollowed PelletsTable 7 - % Moisture Change in Hollowed PelletsExamples 13-20

[0119] The impact of lubricants on drying temperature was assessed where various lubricants were compounded into the composition and tested to determine the maximum temperature that the pellets could be heated to for drying purposes. If the pellets agglomerate, then the air flow is minimized and the drying rate is slowed. In addition, agglomeration can cause feeding / conveying problems from the dryer to downstream processing equipment. The table below shows the max temperature that materials could be dried without agglomeration using the test rig in FIG. 5. As depicted in FIG. 5, PT-1 is a solid platform which is used to stabilize the assembly and is also the holder of two guiding rods, R1 and R2. P-2 is a solid piston that rests on the bottom of platform PT-1. The function of P-2 is to provide a good seal between the polymer in C-l and the platform. C-l is the holding cylinder for the polymer. C-l was designed to create an approximate 1” diameter by 1” tall sample. The cylinder holds approximately 13 grams of pellets. P-1 is a solid piston that creates compression on the polymer in C-l. The piston was designed so that weights could be added to the top. WT-1 are weights that may be in 1 lb, 3 lb, and 5 lb increments. The weights represent the compression effect of the pellets in the top of the dryer on the pellets in the bottom of the dryer.

[0120] All examples have a base composition of 20 wt.% of triacetin, 1.2 wt.% of stabilizers, and the balance Aventa™ FT1200 cellulose acetate. The compositions were heated in a forced air oven under 5 lbs of compression weight and then the assembly was removed and the pellets were evaluated to determine if they were free flowing, no clumping. As shown in the table below, the max temperature for each composition was recorded showing that a drying temperature of at least 10 °C higher can be achieved when using lubricants in the formulation. In addition to improved processing, lubricants can be used to accelerate drying by increasing the drying temperature when used at the concentration.Table 8 - Maximum Drying Temperature Using Lubricants

[0121] The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. Instead, unless otherwise specified, each such dimension is intended to mean both the recited value and a functionally equivalent range surrounding that value. For example, a dimension disclosed as “40 mm” is intended to mean “about 40 mm.”

[0122] Every document cited herein, if any, including any cross- referenced or related patent or application and any patent application or patent to which this application claims priority or benefit thereof, is hereby incorporated herein by reference in its entirety unless expressly excluded or otherwise limited. The citation of any document is not an admission that it is prior art with respect to any invention disclosed or claimed herein or that it alone, or in any combination with any other reference or references, teaches, suggests or discloses any such invention. Further, to the extent that any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition assigned to that term in this document shall govern.

[0123] While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.

Claims

What is claimed is:

1. A method for efficient removal of water from cellulose ester particulates, the method comprising:(a) introducing a composition comprising cellulose ester particulates into a dryer unit, wherein the cellulose ester particulates have a D90 of 0.5 mm to 7.0 mm, an average surface area-to-volume (SA / V) ratio of greater than 1 mm'1to 3 mm1, a gradient tube density of less than 1.35 g / cc, and wherein the cellulose ester particulates are substantially spherical in shape or substantially cylindrical in shape; and(b) passing a drying gas for a period of time T across at least a portion of the cellulose ester particulates to form dried cellulose ester particulates, wherein the drying gas has a temperature of from 30°C to 60°C below the Tg of the composition.

2. A method for efficient removal of water from cellulose ester particulates, the method comprising:(a) introducing a composition comprising cellulose ester particulates into a dryer unit, wherein the cellulose ester particulates have a D90 of 0.5 mm to 7.0 mm, an average surface area-to-volume (SA / V) ratio of greater than 1 mm'1to 3 mm1, a gradient tube density of less than 1.25 g / cc, and wherein the cellulose ester particulates are hollowed; and(b) passing a drying gas for a period of time T across at least a portion of the cellulose ester particulates to form dried cellulose ester particulates, wherein the drying gas has a temperature of from 30°C to 60°C below the Tg of the composition.

3. The method of claims 1 & 2, wherein the composition further comprises one or more additional particulates formed from a biobased polymer.

4. The method of claim 3, wherein the biobased polymer is selected from the group consisting of polyhydroxyalkanoates (PHAs and PHBs), polylactic acid (PLA),poly(gly colic 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 ethers, starch (including modified starches), and combinations thereof.

5. The method of claims 1-4, wherein the cellulose ester particulates comprise cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, or combinations thereof.

6. The method of claim 5, wherein the cellulose ester particulates comprise cellulose acetate having a degree of substitution DSAc of from 1.8 to 2.7.

7. The method of claims 1-6, wherein the composition further comprises from 5 to 40 wt.%, based on the total weight of the composition, of a plasticizer.

8. The method of claim 7, wherein the plasticizer is selected from the group consisting of triacetin, triethyl citrate, acetyl triethyl citrate, dioctyl adipate, bis(2- ethylhexyl)-l,4-benzenedicarboxylate, polyethylene glycol, benzoate containing plasticizers, epoxides, adipates, and combinations thereof.

9. The method of claims 1-8, wherein the composition further comprises from 0.2 to 5 wt.%, based on the total weight of the composition, of a lubricant.

10. The method of claim 9, wherein the lubricant is selected from the group consisting of fatty acids, fatty acid amides, fatty acid esters, metal salts of fatty acids, biodegradable waxes, oils, and combinations thereof.

11. The method of claims 1-10, wherein the drying gas has a temperature of at least 55 °C.

12. The method of claims 1-11, wherein the drying gas has a dew point of not more than 0 °F.

13. The method of claims 1-12, wherein the drying gas is selected from the group consisting of air, nitrogen, argon, helium, and combinations thereof.

14. The method of claims 1-13, wherein the drying unit is a hot air drying unit, desiccant drying unit, or a combination thereof.

15. The method of claims 1-14, wherein the dried cellulose ester particulates have a moisture content of less than 1%, by weight, after a period of time T of 4 hours.

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