Method and system for blending plasticizers with polysaccharide ester polymers - Patents.com

Abstract

A method is disclosed for combining polysaccharide ester polymer with one or more plasticizers in a manner that produces a homogeneous blend. The polysaccharide ester polymer may be in the form of particles and may be fed into a heated extrusion device. A separate amount of plasticizer may then be combined with the polysaccharide ester polymer particles as they are conveyed through the extrusion device. The method of the present disclosure may form a homogeneous blend product that may then be used to form a variety of articles, including fibers, films, and molded articles.

Description

[Technical field]

[0001] Related Applications

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 299,596, having a filing date of January 14, 2022, which is incorporated herein by reference. [Background technology]

[0002]

[0002] Each year, the global production of plastic continues to increase. More than half of the amount of plastic produced each year is used for plastic bottles, containers, drinking straws, and other disposable items. Discarded disposable plastic items, including plastic drinking bottles, are typically not recycled and are sent to landfills. Furthermore, many of these items are not properly disposed of and end up in rivers, lakes, and oceans around the world.

[0003] In view of the above, those skilled in the art have attempted to manufacture plastic articles made from biodegradable polymers. However, many biodegradable polymers do not have the physical properties and characteristics of conventional polymers, such as polypropylene and / or polyethylene terephthalate.

[0004]

[0004] Cellulose esters have been proposed as replacements for some petroleum-based polymers or plastics. They are generally considered to be environmentally friendly polymers, for example because they are recyclable, degradable, and derived from renewable resources such as wood pulp. However, challenges arise in the melt processing of cellulose ester polymers, such as cellulose acetate polymers. The polymeric materials are relatively stiff and have relatively low elongation properties. In addition, the melting temperature of cellulose ester polymers is close to the decomposition temperature of the polymer, which necessitates careful temperature control during melt processing. As a result, cellulose esters are typically combined with plasticizers to improve the melt processing properties of the material. The addition of a plasticizer reduces the melting temperature of the composition and prevents decomposition.

[0005] However, one problem that has been experienced is being able to combine the plasticizer with the cellulose ester quickly and efficiently to produce a homogeneous composition. For example, many plasticizers do not mix easily with cellulose ester particles. If the two components are not mixed properly, it can result in molded articles with imperfections and non-uniform properties. Therefore, in the past, to improve the blending of cellulose ester particles with plasticizers, cellulose ester particles have been ground to a very small size to increase the surface area for contact with the plasticizer. However, grinding cellulose ester particles can add significant costs to the overall process, as well as making small particles difficult to handle and process.

[0006]

[0006] In yet another embodiment, the cellulose ester particles and the plasticizer are premixed and stored before processing to improve blending. Although premixing the two components may provide some improvements, the premixing step requires not only a large amount of time but also a large amount of storage space. Summary of the Invention [Problem to be solved by the invention]

[0007] In view of the above, there is a need for improved methods for combining cellulose ester polymers with plasticizers. [Means for solving the problem]

[0008]

[0008] The present disclosure generally relates to a method for efficiently combining one or more plasticizers with a polysaccharide ester polymer to produce a homogenized polymer resin. The polysaccharide ester polymer may be, for example, a cellulose ester polymer, such as cellulose acetate. In one embodiment, the blend of plasticizer and cellulose ester polymer is extruded into strands, pellets, granules, or powder. The method of the present disclosure allows a relatively large amount of plasticizer to be incorporated into the cellulose ester polymer. The resulting blend of cellulose ester polymer and plasticizer can then be molded into a molded article having uniform properties. The polymeric article made according to the present disclosure may, for example, have excellent mechanical properties as well as aesthetic appeal. The resulting polymeric composition is suitable for the manufacture of polymeric articles, such as beverage holders, other plastic containers, beverage straws, hot beverage pods, automotive parts, consumer goods parts, packaging, and the like.

[0009] In one embodiment, for example, the present disclosure relates to a method for producing a polysaccharide ester polymer product, i.e., a cellulose ester polymer product. The method includes feeding polysaccharide ester polymer particles into a heated extrusion device. The heated extrusion device includes a heated barrel having a length. The method further includes, after the polysaccharide ester polymer particles are heated in the extrusion device, combining the polysaccharide ester polymer particles with a first amount of a first plasticizer in the extrusion device to form a blend of polysaccharide ester polymer particles and the first plasticizer. The blend of polysaccharide ester polymer particles and the first plasticizer is then combined with a second amount of a second plasticizer in the extrusion device downstream of where the polysaccharide ester polymer particles were combined with the first plasticizer. According to the present disclosure, the plasticized polysaccharide ester polymer product is then discharged from the heated extrusion device. For example, the product may be in the form of strands or pellets, which may then be ground into granules or powder.

[0010] As discussed above, the polysaccharide ester polymer particles are combined with two amounts of plasticizer over the length of the heated barrel of the extrusion device. In alternative embodiments, the polysaccharide ester polymer particles may be blended with additional amounts of plasticizer as they are conveyed through the extrusion device. For example, the polysaccharide ester polymer particles may be combined with a third amount of plasticizer, a fourth amount of plasticizer, or a fifth amount of plasticizer. For example, the heated barrel of the extrusion device may include from about 2 to about 10 inlets for receiving an amount of plasticizer for combination with the polysaccharide ester polymer.

[0011] In one embodiment, the first plasticizer combined with the polysaccharide ester polymer particles and the second plasticizer combined with the polysaccharide ester polymer particles may be the same plasticizer or different plasticizers. In one embodiment, the first amount of plasticizer combined with the polysaccharide ester polymer particles may be less than the second amount of plasticizer combined with the polysaccharide ester polymer particles. For example, the weight ratio between the amount of the first plasticizer and the amount of the second plasticizer may be from about 1:1 to about 1:20, such as from about 1:2 to about 1:12, such as from about 1:2 to about 1:7. In one embodiment, the first plasticizer is incorporated into the polysaccharide ester polymer product in an amount of from about 2% to about 6% by weight, while the second plasticizer is incorporated into the polysaccharide ester polymer product in an amount of from about 2% to about 14% by weight.

[0012]

[0012] The total amount of plasticizer incorporated into the polysaccharide ester polymer product may vary depending on the particular application and the desired results. For example, one or more plasticizers may be incorporated into the product in an amount greater than about 5% by weight, such as greater than about 14% by weight, such as greater than about 18% by weight, such as greater than about 20% by weight, such as greater than about 22% by weight, such as greater than about 24% by weight, and generally less than about 40% by weight, such as less than about 30% by weight.

[0013]

[0013] The polysaccharide ester polymer particles fed to the extrusion device may optionally be pre-dried. For example, the particles may have a moisture content of less than about 8% by weight, such as less than about 6% by weight, such as less than about 4% by weight, such as less than about 2% by weight, such as less than about 1% by weight. In one embodiment, a portion of the polysaccharide ester polymer fed to the extrusion device may be pre-blended with one or more additives. The one or more additives may include antioxidants, stabilizers, organic acids, oils, filler particles, glass fibers, pigments, bio-based polymers other than cellulose esters, biodegradation enhancers, or mixtures thereof.

[0014] As mentioned above, the first plasticizer may be the same as or different from the second plasticizer. Any suitable plasticizer may be combined with the polysaccharide ester polymer particles. In one embodiment, the plasticizer is a polyalkylene glycol, such as polyethylene glycol. Other examples of plasticizers include tris(chloroisopropyl)phosphate, tris(2-chloro-1-methylethyl)phosphate, glycerin, monoacetin, triethyl citrate, acetyl triethyl citrate, phthalate, adipate, polyethylene glycol, triacetin, diacetin, trimethyl phosphate, triethyl phosphate, tributyl phosphate, triphenyl phosphate, triethyl-o-acetyl citrate, diethyl tartrate, ethyl o-benzoyl benzoate, n-ethyl toluenesulfonamide, o-cresyl p-toluenesulfonate, aromatic diols, substituted aromatic diols, aromatic ethers, tripropionin, tribenzoin, glycerin esters, glycerol tribenzoate, glycerol acetate benzoate, polyethylene glycol esters, polyethylene glycol diesters, di-2-ethylhexyl polyethylene glycol esters, glycerol ... esters, diethylene glycol, polypropylene glycol, polyglycol diglycidyl ethers, dimethyl sulfoxide, N-methylpyrrolidinone, propylene carbonate, C1-C20 dicarboxylic acid esters, dibutyl maleate, dioctyl maleate, resorcinol monoacetate, catechol, catechol esters, phenols, epoxidized soybean oil, castor oil, linseed oil, epoxidized linseed oil, bifunctional glycidyl ethers based on polyethylene glycol, alkyl lactones, phospholipids, 2-phenoxyethanol, acetylsalicylic acid, acetaminophen, naproxen, imidazole, triethanolamine, benzoic acid, benzyl benzoate, salicylic acid, 4-hydroxybenzoic acid, propyl-4-hydroxybenzoate, methyl-4-hydroxybenzoate, ethyl-4-hydroxybenzoate, benzyl-4-hydroxybenzoate, glyceryl tribenzoate, neopentyl dibenzoate,triethylene glycol dibenzoate, trimethylolethane tribenzoate, butylated hydroxytoluene, butylated hydroxyanisole, sorbitol, xylitol, ethylenediamine, piperidine, piperazine, hexamethylenediamine, triazine, triazole, pyrrole, or mixtures thereof.

[0015] The plasticized polysaccharide ester polymer products of the present disclosure may generally contain cellulose ester in an amount of about 15% to about 95% by weight, such as about 60% to about 95% by weight. One or more plasticizers may be present in an amount of about 3% to about 40% by weight, such as about 3% to about 35% by weight.

[0016]

[0016] Other features and aspects of the present disclosure are discussed in more detail below.

[0017] A full and enabling disclosure of the present disclosure is set forth in more detail in the remainder of the specification, including references to the accompanying drawings. [Brief description of the drawings]

[0017] [Figure 1]

[0018] FIG. 1 illustrates one exemplary embodiment of a process flow diagram according to the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018]

[0019] Repeat use of reference characters in the present specification and drawings is intended to represent same or analogous features or elements of the invention.

[0020] Those skilled in the art will appreciate that this discussion is merely a description of example embodiments and is not intended as limiting the broader aspects of the present disclosure.

[0019]

[0021] The present disclosure relates generally to a method for improving the incorporation of one or more plasticizers into polysaccharide ester polymers, such as cellulose ester polymers. The present disclosure also relates to products made from the method.

[0020]

[0022] In one embodiment, a pre-formulated product is produced that contains a substantially homogeneous blend of polysaccharide ester polymer, one or more plasticizers, in addition to one or more additives.The plasticized polysaccharide ester product can be used to mold all kinds of different articles.For example, the plasticized polysaccharide ester product or cellulose ester product can have improved melt processing properties, and can produce moldings and molded articles with better and more uniform properties and characteristics.

[0021]

[0023] The method of the present disclosure generally comprises the step of combining cellulose ester particles with two or more amounts of plasticizers when the cellulose ester particles are heated to a molten state and fed through a heated extrusion device.It has been found that combining cellulose ester particles with two or more amounts of plasticizers when the cellulose ester polymer is moving through an extruder dramatically improves the ability of cellulose ester particles and one or more plasticizers to blend together and form a homogeneous composition.Particularly advantageously, one or more additives can also be blended into the final product during the method.

[0022]

[0024] The method of the present disclosure allows cellulose ester particles and one or more plasticizers to be combined together in a single process step when cellulose ester particles are extruded.As a result, the method of the present disclosure makes it unnecessary to pre-blend one or more plasticizers with cellulose ester particles before melt processing.In addition, the method of the present disclosure also makes it unnecessary to first grind cellulose ester particles to smaller size before combining with one or more plasticizers.

[0023]

[0025] The method of the present disclosure also allows the incorporation of a significant amount of plasticizer into cellulose ester polymer product without the previously occurring problems of phase separation and leaching.For example, one or more plasticizers may be present in the cellulose ester polymer product in an amount of about 5% to about 40% by weight.In one embodiment, one or more plasticizers may be present in the product in an amount greater than about 10% by weight, such as greater than about 15% by weight, such as greater than about 18% by weight, such as greater than about 20% by weight, such as greater than about 22% by weight, such as greater than about 24% by weight, such as greater than about 26% by weight, such as greater than about 28% by weight.

[0024]

[0026] The method of the present disclosure can also significantly improve the characteristics of molded articles made from plasticized polymers.For example, in the past, plasticized cellulose ester particles have been formed with insufficient mixing and gel formation in extrudates and products.Gel formation during processing can not only adversely affect the physical properties of any resulting products, but also the appearance of any products formed.However, articles made according to the present disclosure can show dramatically lower defect levels when tested according to gel analysis test.For example, gel analysis can be performed on films formed from plasticized polymer products.

[0025]

[0027] Gel analysis testing can be performed with an FSA-100 film surface analyzer available from OCS GmbH (Witten, Germany). The film surface analyzer can include a 4096 pixel CMOS digital camera with a complementary metal oxide semiconductor sensor. The film surface analyzer can have a nominal resolution of 50 microns and can include an LED illumination system that allows optimal defect detection in transparent, opaque and colored polymeric films. Films can be tested at any suitable thickness, for example, 25.4 microns, in accordance with the present disclosure. The FSA LID setting is set to 40. The parcel length is set to 102.4 mm and the parcel width is set to 80.00 mm. The parcel area is 8192.00 mm. 2367 parcels were inspected, with an inspection area of ​​3.006 m 2 The length inspected is 37.581 m. The levels are set at 40%-10%-. Other settings include a gray value of 169, an average filter size of 50 (50), a film speed of 7.01 m / min, an exposure time of 0.013 ms, transparency / noise set at 98.88% / 2.83%, X resolution set at 50 microns, and Y resolution set at 50 microns. The gel analysis test measures the number of defects per area and the size of the defects.

[0026]

[0028] For example, films and articles made according to the present disclosure have less than about 5,000 defects / m 2 , e.g. less than about 3,500 defects / m 2 , e.g. less than about 2,000 defects / m 2 The films and articles made according to the present disclosure may display defects having a size of 300 microns or greater. 2 amount, e.g. less than about 20,000 defects / m 2 amount, e.g. less than about 15,000 defects / m 2 The films and articles made according to the present disclosure may display defects having a size of 200 microns or greater. 2 amount, e.g. less than about 60,000 defects / m 2 amount, e.g. less than about 50,000 defects / m 2 The amount of defects having a size of 100 microns or more may be displayed.

[0027]

[0029] Films and articles made according to the present disclosure have a thickness of about 9,000 mm 2 Less than, for example, about 8,000 mm 2 Less than, for example, about 7,000 mm 2 Less than, for example, about 6,000 mm 2 Less than, for example, about 5,000 mm 2 Less than, for example, about 4,000 mm 2 Less than, for example, about 3,000 mm 2 Less than, for example, about 2,000 mm2 The total defect area may be less than 1 mm.

[0028]

[0030] The above gel analysis characteristics can result in films and articles that exhibit excellent haze and clarity.

[0031] For example, polymeric articles made according to the present disclosure can be measured for haze according to ASTM test D1003 (2013). Haze can be measured using any recognized instrument according to ASTM test, including, for example, BYK Gardner Haze-Gard 4725 instrument. Haze can be measured on test plaques, films, or final thermoformed articles made according to the present disclosure. The test plaques can have any suitable thickness, for example, 1 mm, 2 mm, 3 mm, or 4 mm. When any of the above samples are tested, the haze of the sample or article can generally be less than about 10%, for example less than about 8%, for example less than about 5%, for example less than about 3%, for example less than about 2%. In one embodiment, the haze can be less than 1%, for example less than about 0.8%, for example less than about 0.5%, for example less than about 0.4%, for example less than about 0.3%, for example less than about 0.2%.

[0029]

[0032] Generally, any suitable polysaccharide ester polymer, particularly any suitable cellulose ester polymer, may be used in the method of the present disclosure.In one embodiment, the cellulose ester polymer may be cellulose acetate, such as cellulose diacetate, cellulose triacetate, cellulose acetate propionate, cellulose acetate butyrate, etc.In addition, various other modified cellulose esters may be used.

[0030]

[0033] Cellulose acetate can be formed by activating cellulose with acetic acid and then esterifying cellulose.Cellulose can be obtained from many types of cellulose materials, including but not limited to plant-derived biomass, corn stover, sugarcane stalk, bagasse and sugarcane pomace, rice and wheat straw, agricultural grasses, broadleaf trees, broadleaf pulp, softwood, softwood pulp, cotton linters, switchgrass, bagasse, herbs, recycled paper, waste paper, wood chips, pulp and paper waste, waste wood, thinnings, willow, poplar, perennial grasses (e.g., Miscanthus), bacterial cellulose, seed husks (e.g., soybeans), corn stalks, rice husks, and other forms of wood, bamboo, soybean hulls, bast fibers, such as kenaf, hemp, jute, and flax, agricultural residue products, agricultural waste, livestock waste, microorganisms, algae cellulose, seaweed, and all other materials that are mostly or completely plant-derived. Such cellulosic raw materials are preferably processed into pellets, chips, clips, sheets, worn fibers, powder form, or other forms that make them suitable for further purification.

[0031]

[0034] Cellulose esters suitable for use in the methods of the present disclosure, in some embodiments, include, but are not limited to, C1-C 20 Aliphatic esters (e.g. acetate, propionate or butyrate), functionality C1-C 20 Having ester substituents, including aliphatic esters (e.g., succinate, glutarate, maleate), aromatic esters (e.g., benzoate or phthalate), substituted aromatic esters, any derivatives thereof, and any combinations thereof.

[0032]

[0035] The cellulose acetate used in the method can be cellulose diacetate or cellulose triacetate.In one embodiment, cellulose acetate mainly comprises cellulose diacetate.For example, cellulose acetate can contain less than 1% by weight of cellulose triacetate, for example less than about 0.5% by weight of cellulose triacetate.Cellulose diacetate can be more than 90% by weight of cellulose acetate, for example more than about 95% by weight of cellulose acetate, for example more than about 98% by weight, for example more than about 99% by weight.

[0033]

[0036] Generally, cellulose acetate may have a molecular weight of more than about 10,000, for example more than about 20,000, for example more than about 30,000, for example more than about 40,000, for example more than about 50,000.The molecular weight of cellulose acetate is generally less than about 300,000, for example less than about 250,000, for example less than about 200,000, for example less than about 150,000, for example less than about 100,000, for example less than about 90,000, for example less than about 70,000, for example less than about 50,000.The molecular weight specified above refers to number average molecular weight.Molecular weight can be determined using gel permeation chromatography using polystyrene standard or standard.

[0034]

[0037] Generally, cellulose ester polymers can have an acetyl substitution degree of about 1.8 to about 3.4, for example, about 2.1 to about 2.8 (including all increments of 0.1 therebetween).The substitution degree of cellulose ester can be measured using ASTM test 871-96 (2010).In one embodiment, the substitution degree is greater than about 2.2, for example greater than about 2.3, for example greater than about 2.4, and generally less than about 2.9, for example less than about 2.8, for example less than about 2.7, for example less than about 2.6.

[0035]

[0038] The cellulose ester polymer or cellulose acetate may generally have an intrinsic viscosity of more than about 0.5 dL / g, such as more than about 0.8 dL / g, such as more than about 1 dL / g, such as more than about 1.2 dL / g, such as more than about 1.4 dL / g, such as more than about 1.6 dL / g. The intrinsic viscosity is generally less than about 2 dL / g, such as less than about 1.8 dL / g, such as less than about 1.7 dL / g, such as less than about 1.65 dL / g. The intrinsic viscosity may be measured by forming a solution of 0.20 g / dL of cellulose ester in 98 / 2 wt / wt acetone / water and measuring the flow time of the solution and the solvent at 30°C with a #25 Cannon-Ubbehlode viscometer. The intrinsic viscosity ("IV") may then be determined using a modified Baker-Philippoff equation, which is Equation 1 for this solvent system.

[0036]

number

[0037] t1=average flow time of the solution (with cellulose ester) (sec), t2=average flow time of the solvent (sec), k=solvent constant (10 for 98 / 2 wt / wt acetone / water), and c=concentration (0.200 g / dL).

[0038]

[0039] The cellulose ester polymer that is combined with one or more plasticizers according to the method of the present disclosure is in the form of particles. For example, the cellulose ester particles may have a round shape, an irregular shape, or may be in the shape of a flake.

[0039]

[0040] As mentioned above, one of the advantages of the method of the present disclosure is the ability to process cellulose ester particles without the need to grind cellulose ester particles in "raw" state to smaller size or subject them to drying process.As a result, in one embodiment, the cellulose ester particles fed into the process are unprocessed flakes as produced by cellulose ester polymer process.For example, in one embodiment, more than about 50% by weight, for example more than about 60% by weight, for example more than about 70% by weight, of the cellulose ester particles have a particle size of more than about 850 microns.Particle size can be determined according to sieve test using a standard size sieve screen.For example, particle size can be determined by placing 200 grams of particle sample into RO-TAP AS200 automatic shaker available from Retsch, which contains different size sieve screens.The amplitude setting is 1.25 mm / g, and the shaking time is 15 minutes.

[0040]

[0041] In one embodiment, more than about 20% by weight of cellulose ester particles, for example more than about 25% by weight, for example more than about 30% by weight, for example more than about 40% by weight, for example more than about 45% by weight, have a particle size of more than about 2,000 microns.Generally, less than about 70% by weight, for example less than about 90% by weight, have a particle size of more than 2,000 microns.In one embodiment, less than 50% by weight, for example less than about 40% by weight, for example less than about 30% by weight, for example less than about 20% by weight, have a particle size of less than 500 microns.Some of the particles contained in cellulose ester can have a particle size of up to about 50,000 microns, for example up to about 30,000 microns, for example up to about 25,000 microns.

[0041]

[0042] When in the form of flakes, the cellulose ester particles may have an aspect ratio of greater than about 1:4 (thickness to largest dimension), such as greater than about 1:8, such as greater than about 1:12, such as greater than about 1:20, such as greater than about 1:30, such as greater than about 1:40, and generally less than about 1:100, such as less than about 1:50.

[0042]

[0043] The cellulose ester particles fed to the method of the present disclosure may have a relatively large size, but in one embodiment, flakes or particles may be ground.The particle size of cellulose ester may vary, for example, depending on specific application and desired results.In one embodiment, the average particle size of cellulose ester particles may be greater than about 10 microns, for example greater than about 50 microns, for example greater than about 70 microns, for example greater than about 100 microns, for example greater than about 120 microns, for example greater than about 140 microns.The average particle size of ground cellulose ester particles may generally be less than about 500 microns, for example less than about 400 microns, for example less than about 300 microns, for example less than about 200 microns, for example less than about 160 microns.

[0043]

[0044] The cellulose ester particles that are fed to the method of the present disclosure may generally have a moisture content of less than about 10%, for example less than about 8%, for example less than about 6%, for example less than about 4%, for example less than about 2%, for example less than about 1%.Optionally, the cellulose ester particles may be preheated or dried before being fed to the method and contacted with plasticizer and wetting agent.For example, the cellulose ester particles may be preheated or dried so that the particles contain moisture or water in an amount of less than about 2% by weight, for example less than about 1.5% by weight, for example less than about 1% by weight, for example less than about 0.7% by weight.The cellulose ester particles generally contain water in an amount of more than about 0.1% by weight.

[0044]

[0045] The cellulose ester particles may optionally be preheated to a temperature greater than about 40°C, such as greater than about 50°C, such as greater than about 55°C, such as greater than about 60°C, such as greater than about 70°C, such as greater than about 80°C, and generally less than about 90°C, such as less than about 80°C.

[0045]

[0046] The cellulose ester particles of the present disclosure are fed into a heated extrusion device to be combined with different and separate amounts of one or more plasticizers as the particles are heated, converted to a molten state, and extruded into a product such as pellets or strands. For example, referring to FIG. 1, an embodiment of the method according to the present disclosure is shown. More specifically, FIG. 1 shows a heated extrusion device 10 that can be used to combine the cellulose ester particles with one or more plasticizers. As shown, the extrusion device 10 is arranged in association with a hopper 12 for feeding the cellulose ester particles to the extrusion device 10. The cellulose ester particles may be held in a storage container 14 and fed to the extrusion device 10 by gravity. Alternatively, the cellulose ester particles may be subjected to an external force to meter the particles into the extrusion device 10.

[0046]

[0047] The heated extrusion device 10 may include a barrel 16, which may be comprised of multiple barrel sections. The barrel 16 may be designed to include one or more extrusion screws axially disposed therein. The extrusion screws may be driven by a screw drive motor.

[0047]

[0048] The barrel 16 may be heated using any suitable heating device or technique. Different barrel sections of the barrel 16 may be configured such that the temperature in each section may be controlled. The temperature in the barrel 16 during processing may generally be greater than about 160° C., such as greater than about 180° C., such as greater than about 200° C., such as greater than about 220° C. The temperature is generally less than about 260° C., such as less than about 250° C., such as less than about 240° C., such as less than about 220° C., such as less than about 200° C. The barrel 16 of the extrusion device 10 may have a temperature profile from a first end where the hopper 12 is located to a second end where the extrusion product is formed. In one embodiment, the temperature may gradually increase from one end to the other end. Alternatively, the temperature may increase and then decrease over the length of the barrel 16.

[0048]

[0049] As shown in FIG. 1, the method includes a plasticizer supply 18 in fluid communication with at least two ports located along the length of the barrel 16. The plasticizer supply 18 is for supplying one or more plasticizers to the extrusion device 10 for mixing with the cellulose ester polymer being conveyed through the extrusion device 10. In the embodiment shown in FIG. 1, two injection ports 20 and 22 are shown. However, it should be understood that the heated extrusion device 10 may include more than two plasticizer injection ports. For example, the extrusion device 10 may include three, four, five, six, seven, eight, nine, or ten plasticizer injection ports. The number of plasticizer injection ports may vary depending on the amount of plasticizer incorporated into the polymer, the type of plasticizer, the temperature of the extrusion device 10, the molecular weight of the cellulose ester polymer, etc.

[0049]

[0050] According to the present disclosure, cellulose ester particles are fed into extrusion device 10, heated, and then mixed with different amounts of plasticizer as the cellulose ester polymer is conveyed through barrel 16. For example, the cellulose ester polymer may be combined with a first amount of plasticizer at first plasticizer injection port 20. Once the cellulose ester polymer has been combined and mixed with the first amount of plasticizer, a second amount of plasticizer may then be fed into extrusion device 10 through second plasticizer injection port 22 for further blending with the cellulose ester polymer.

[0050]

[0051] The amount of plasticizer fed into the extrusion device 10 at the first injection port 20 and the amount of plasticizer fed into the extrusion device 10 through the second plasticizer injection port 22 can be varied to optimize a homogeneous blend with the polymer. In one aspect, the first amount of plasticizer is less than the second amount of plasticizer. In an alternative embodiment, the first amount of plasticizer may be the same amount as the second amount of plasticizer. In yet another embodiment, the second amount of plasticizer may be less than the first amount of plasticizer.

[0051]

[0052] In one embodiment, the first plasticizer injection port 20 is used to add a first plasticizer to the cellulose ester polymer in an amount of about 2% to about 6% by weight (including all 0.1% by weight increments therebetween). The second plasticizer injection port 22 can inject a second plasticizer into the extruder 10 in an amount of more than about 2% by weight, such as more than about 4% by weight, such as more than about 6% by weight, such as more than about 8% by weight, such as more than about 10% by weight, such as more than about 12% by weight, such as more than about 14% by weight, such as more than about 16% by weight, such as more than about 18% by weight, such as more than about 20% by weight, such as more than about 22% by weight, such as more than about 24% by weight, such as more than about 26% by weight, based on the weight of the cellulose ester polymer blend contained in the extrusion device. The amount of the second plasticizer injected into the extrusion device 10 at the second plasticizer injection port 22 is generally less than about 34% by weight, such as less than about 30% by weight, such as less than about 26% by weight, based on the weight of the cellulose ester polymer blend contained within the extrusion device.

[0052]

[0053] In methods and systems including two plasticizer injection ports, the weight ratio between the first plasticizer and the second plasticizer may be, in one aspect, about 1:1 to about 1:20, such as about 1:2 to about 1:12, such as about 1:2 to about 1:7. The first plasticizer may be the same as the second plasticizer. Alternatively, the first plasticizer may be different from the second plasticizer. In yet another embodiment, a plasticizer blend containing two or more plasticizers may be injected at one or more plasticizer injection ports.

[0053]

[0054] In the embodiment shown in FIG. 1, the system includes two plasticizer injection ports. As mentioned above, up to 10 plasticizer injection ports may be incorporated into the process. Each plasticizer injection port may inject an amount of plasticizer from about 1% to about 20% by weight (including all increments of 0.5% by weight therebetween) based on the total weight of the final product produced by the process. For example, when three or more plasticizer injection ports are included, the amount of plasticizer incorporated into the plasticized product at each injection port may be greater than about 2% by weight, such as greater than about 4% by weight, such as greater than about 6% by weight, such as greater than about 8% by weight, such as greater than about 10% by weight, such as greater than about 12% by weight, and generally less than about 20% by weight, such as less than about 16% by weight, such as less than about 12% by weight, such as less than about 8% by weight.

[0054]

[0055] In addition to the polysaccharide ester polymer, such as a cellulose ester polymer, and one or more plasticizers, the method of the present disclosure shown in FIG. 1 is also suitable for incorporating one or more additives into the plasticized and compounded product. For example, as shown in FIG. 1, the method may include an additive feed 24 that may feed additives to the hopper 12. Additives that may be incorporated into the product include antioxidants, colorants, lubricants, softeners, acid scavengers, antimicrobial agents, preservatives, flame retardants, combinations thereof, and the like. In one embodiment, one or more additives may be pre-compounded with the cellulose ester polymer to produce a masterbatch of the cellulose ester polymer and additives, which is then combined with a larger amount of cellulose ester particles and fed to the heated extrusion device 10. In one embodiment, the masterbatch may contain one or more stabilizers, such as antioxidants, light stabilizers, heat stabilizers, and the like.

[0055]

[0056] 1, the system may include one or more devolatilization zones 26, which may be equipped with one or more vents and may optionally be coupled to a vacuum. The devolatilization zones may allow any volatile materials, including evaporated water, to escape from the extrusion device 10. For example, the systems and methods of the present disclosure may generally include from about 1 to about 4 devolatilization zones spaced along the length of the barrel 16.

[0056]

[0057] At the end of barrel 16 is a die plate 28 designed to form the desired size and shape of the cellulose ester product. For example, in one embodiment, die plate 34 may be designed to produce strands containing the plasticized cellulose ester product. The strands or other shapes may then be fed into a water bath 30 and then into a pelletizing device 32. For example, in one embodiment, the strands may be extruded in a process and then cut into pellets in pelletizing device 32.

[0057]

[0058] Optionally, the pellets may then be fed to a sorter 34, which may include metal detection and separation devices. From the sorter 34, the pellets may be fed to storage totes 36 that are used to produce molded articles in downstream processes. For example, the formed pellets may then be used to produce films, fibers, and all different types of molded articles. For example, the pellets may be fed to a film forming process, a fiber forming process, an injection molding process, a blow molding process, a thermoforming process, etc. In one embodiment, the pellets may be fed to a foam forming process to form a foam article.

[0058]

[0059] Generally, any suitable plasticizer or blend of plasticizers can be combined with the cellulose ester particles during the process.

[0060] Particularly suitable plasticizers for use in the method include triacetin, monoacetin, diacetin, or mixtures thereof. Other suitable plasticizers include tris(chloroisopropyl)phosphate, tris(2-chloro-1-methylethyl)phosphate, triethyl citrate, acetyl triethyl citrate, glycerin, polyethylene glycol, or mixtures thereof.

[0059]

[0061] Other examples of plasticizers include, but are not limited to, trimethyl phosphate, triethyl phosphate, tributyl phosphate, triphenyl phosphate, acetyl tributyl citrate, tributyl-o-acetyl citrate, dibutyl tartrate, ethyl o-benzoyl benzoate, n-ethyl toluene sulfonamide, o-cresyl p-toluene sulfonate, aromatic diols, substituted aromatic diols, aromatic ethers, tripropionine, tribenzoin, glycerin, glycerin esters, glycerol tribenzoate, glycerol acetate benzoate, polyethylene glycol esters, polyethylene glycol diesters, di-2-ethylhexyl polyethylene glycol esters, glycerol esters, diethylene glycol, polypropylene glycol, polyglycol diglycidyl ether, dimethyl sulfoxide, N-methylpyrrolidinone, propylene carbonate, C1-C 20Dicarboxylic acid esters, dimethyl adipate (or other dialkyl esters), dibutyl maleate, dioctyl maleate, resorcinol monoacetate, catechol, catechol esters, phenols, epoxidized soybean oil, castor oil, linseed oil, epoxidized linseed oil, other vegetable oils, other seed oils, difunctional glycidyl ethers based on polyethylene glycol, alkyl lactones (e.g., gamma-valerolactone), alkyl phosphate esters, aryl phosphate esters, phospholipids, fragrances (including some of those described herein, e.g., eugenol, cinnamyl alcohol, camphor, methoxyhydroxyacetophenone (acetovanillone), vanillin, or ethyl vanillin), 2-phenoxyethanol, glycol ethers, glycol esters, glycol ester ethers, polyglycol ethers, polyglycol esters, ethylene glycol ethers, propylene ... ether, ethylene glycol esters (e.g., ethylene glycol diacetate), propylene glycol esters, polypropylene glycol esters, acetylsalicylic acid, acetaminophen, naproxen, imidazole, triethanolamine, benzoic acid, benzyl benzoate, salicylic acid, 4-hydroxybenzoic acid, propyl-4-hydroxybenzoate, methyl-4-hydroxybenzoate, ethyl-4-hydroxybenzoate, benzyl-4-hydroxybenzoate, glyceryl tribenzoate, neopentyl dibenzoate, triethylene glycol dibenzoate, trimethylolethane tribenzoate, butylated hydroxytoluene, butylated hydroxyanisole, sorbitol, xylitol, ethylenediamine, piperidine, piperazine, hexamethylenediamine, triazine, triazole, pyrrole, and the like, or any derivative thereof, or any combination thereof.

[0060]

[0062] In one embodiment, carbonate ester can function as a plasticizer.Exemplary carbonate ester can include, but is not limited to, propylene carbonate, butylene carbonate, diphenyl carbonate, phenyl methyl carbonate, dicresyl carbonate, glycerin carbonate, dimethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, isopropyl phenyl 2-ethylhexyl carbonate, phenyl 2-ethylhexyl carbonate, isopropyl phenyl isodecyl carbonate, isopropyl phenyl tridecyl carbonate, phenyl tridecyl carbonate, etc., or any combination thereof.

[0061]

[0063] In yet another embodiment, the plasticizer may be a polyol benzoate. Exemplary polyol benzoates may include, but are not limited to, glyceryl tribenzoate, propylene glycol dibenzoate, diethylene glycol dibenzoate, dipropylene glycol dibenzoate, triethylene glycol dibenzoate, sucrose benzoate, polyethylene glycol dibenzoate, neopentyl glycol dibenzoate, trimethylolpropane tribenzoate, trimethylolethane tribenzoate, pentaerythritol tetrabenzoate, sucrose benzoate (degree of substitution 1-8), or combinations thereof. In some cases, tribenzoates such as glyceryl tribenzoate may be preferred. In some cases, the polyol benzoate may be solid at 25°C and have a water solubility of less than 0.05g / 100mL at 25°C.

[0062]

[0064] The plasticizer may also be bio-based. Particularly suitable bio-based plasticizers for use in the compositions of the present disclosure include alkyl ketal esters, non-petroleum hydrocarbon esters, bio-based polymers or oligomers having a number average molecular weight of 1000 or less, such as polycaprolactone, or mixtures thereof.

[0063]

[0065] In one embodiment, the bio-based plasticizer is an alkyl ketal ester having a chemical structure corresponding to Structure I, depicted below:

[0064] [ka]

[0065] [In the formula, a is 0 to 12; b is 0 or 1; each R 1 is independently hydrogen, a hydrocarbyl group, or a substituted hydrocarbyl group; each R 2 , R 3 , and R 4 is independently methylene, alkylmethylene, or dialkylmethylene, x is at least 1, y is 0 or a positive number, and x+y is at least 2; R 6 is a hydrocarbyl group or a substituted hydrocarbyl group, each Z is independently -O-, -NH- or -NR-, and R is a hydrocarbyl group or a substituted hydrocarbyl group.

[0066] The plasticizers identified above correspond to the reaction products of polyols, aminoalcohols or polyamines with certain 1,2- and / or 1,3-alkanediol ketals of oxocarboxylate esters. The 1,2- and 1,3-alkanediol ketals of oxocarboxylate esters are referred to herein as "alkyl ketal esters." Up to one mole of alkyl ketal ester may be reacted per equivalent of hydroxyl or amino groups provided by the polyol, aminoalcohol or polyamine. The polyol, aminoalcohol or polyamine is most preferably difunctional, although polyols, aminoalcohols and polyamines having three or more hydroxyl and / or amino groups may be used.

[0067] The values ​​of x and y in Structure I depend on the number of hydroxyl or amino groups on the polyol, aminoalcohol or polyamine, the number of moles of alkyl ketal ester per mole of polyol, aminoalcohol or polyamine, and the extent to which the reaction goes to completion. Higher amounts of alkyl ketal ester favor lower values ​​of y and higher values ​​of x.

[0068] In Structure I, y is specifically 0 to 2, and x is specifically at least 2. All a's in Structure I are specifically 2 to 12, more specifically 2 to 10, more specifically 2 to 8, more specifically 2 to 6, more specifically 2 to 4, and more specifically 2. 1 are all specifically alkyl groups, specifically methyl. In some embodiments of structure I, all Z's are -O-, y's are 0, and x's are 2; these products correspond to the reaction of two moles of alkyl ketal ester and one mole of diol. In some other embodiments, all Z's are -O-, y's are 1, and x's are 1; these products correspond to the reaction of one mole of alkyl ketal ester and one mole of diol.

[0069] In one embodiment, all b's are 0. In another embodiment, all b's are 1.

[0070] Some specific compounds according to structure I have the structure:

[0070] [ka]

[0071] or structure

[0072] [ka]

[0073] or structure

[0074] [ka]

[0075] In particular, those having the formula 6 Ha-(CH2)- m and m is 2 to 18, in particular 2, 3, 4 or 6. In one particular embodiment, R 6 corresponds to the residue of 1,4-butanediol, after removal of the hydroxyl groups, resulting in structure (Ia).

[0076] [ka]

[0077] In another particular embodiment, R 6 corresponds to the residue of diethylene glycol, after removal of the hydroxyl group, resulting in structure (Ib).

[0078] [ka]

[0079] In another particular embodiment, R 6 corresponds to the residue of 2-methyl, 1,3-propanediol, after removal of the hydroxyl group, resulting in structure (Ic).

[0080] [ka]

[0081] Compounds according to structure I can be prepared in a transesterification or ester-aminolysis reaction between the corresponding polyol, aminoalcohol or polyamine and the corresponding alkyl ketal ester. Alternatively, compounds according to structure I can be prepared by reacting an oxocarboxylic acid with a polyol, aminoalcohol or polyamine to form an ester or amide, and then ketalizing the resulting product with a 1,2- or 1,3-alkanediol, such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl, 1-3 propanediol, 1,2-butanediol, 1,3-butanediol, 1,2-pentanediol, 1,3-pentanediol, 1,2-hexanediol, 1,3-hexanediol, and the like.

[0082] Another bio-based plasticizer that may be incorporated into the polymer composition of the present disclosure is a non-petroleum hydrocarbon ester. For example, one example of a non-petroleum hydrocarbon ester is sold under the trade name HALLGREEN by Hall Star Company (Chicago, Illinois). For example, the non-petroleum hydrocarbon ester plasticizer may contain more than about 50% by weight, such as more than about 70% by weight, such as more than about 99% by weight of bio-based content. For example, the ester may be obtained primarily from agricultural, forestry or marine materials and is therefore biodegradable. In one embodiment, the non-petroleum hydrocarbon ester plasticizer has a specific gravity at 25° C. of about 1.16 or more, such as about 1.165 or more, such as about 1.17 or more, such as about 1.74 or more, and generally about 1.19 or less, such as about 1.185 or less, such as about 1.18 or less, such as about 1.78 or less. The non-petroleum hydrocarbon ester plasticizer may have an acid value of about 0.5 mg KOH / g to about 0.6 mg KOH / g, for example, about 0.53 mg KOH / g to about 0.57 mg KOH / g.

[0083] In one embodiment, the plasticizer is phthalate-free. Indeed, the polymer composition and product may be formulated to be phthalate-free. For example, phthalates may be present in the polymer composition and / or product in an amount of about 0.5% or less, such as about 0.1% or less.

[0084] The amounts of cellulose ester and plasticizer combined together can vary depending on the particular application.

[0077] Cellulose acetate is generally present in the polymer composition or product in an amount greater than about 15% by weight, such as greater than about 25% by weight, such as greater than about 35% by weight, such as greater than about 45% by weight, such as greater than about 55% by weight.Cellulose acetate is generally present in the polymer composition in an amount less than about 95% by weight, such as less than about 85% by weight, such as less than about 75% by weight, such as less than about 70% by weight, such as less than about 65% by weight.

[0085]

[0078] In general, one or more plasticizers may be present in the polymer composition or product in an amount of about 8% to about 40% by weight, such as about 12% to about 35% by weight. In one embodiment, a relatively large amount of plasticizer is incorporated into the product, such as about 18% to about 32% by weight, such as about 20% to about 26% by weight. In another aspect, the amount of plasticizer is relatively small. For example, one or more plasticizers may be present in the polymer composition in an amount of about 17% or less, such as about 15% or less, such as about 12% or less, such as about 10% or less, such as about 8% or less.

[0086]

[0079] The cellulose acetate may be present relative to the plasticizer(s) such that the weight ratio between the cellulose acetate and the one or more plasticizers is about 60:40 to about 85:15, for example about 70:30 to about 80:20. In one embodiment, the weight ratio of cellulose acetate to plasticizer is about 75:25.

[0087]

[0080] In addition to the cellulose ester polymer and one or more plasticizers as described above, the plasticized cellulose ester products of the present disclosure may also contain various other additives and ingredients as described above. These additives and ingredients may be incorporated into the product during the formation of the pellets. Alternatively, these additives and ingredients may be incorporated into a downstream molding process for incorporation into the final product being formed.

[0088] For example, the polymer composition may contain antioxidants, pigments, lubricants, softeners, acid scavengers, antibacterial agents, antifungal agents, preservatives, flame retardants, or combinations thereof. Each of the above additives may generally be present in the polymer composition in an amount of about 5% or less, such as about 2% or less, and generally in an amount of about 0.1% or more, such as about 0.3% or more.

[0089]

[0082] Flame retardants suitable for use in conjunction with the cellulose ester plastics described herein, in some embodiments, may include, but are not limited to, silica, metal oxides, phosphates, catechol phosphates, resorcinol phosphates, borates, inorganic hydrates, aromatic polyhalides, and the like, or any combination thereof.

[0090] Antifungal and / or antibacterial agents suitable for use in combination with the cellulose ester plastics described herein include, in some embodiments, but are not limited to, polyene antifungals (e.g., natamycin, rimocidin, filipin, nystatin, amphotericin B, candicin, or hamycin), imidazole antifungals such as miconazole (available as MICATIN® from WellSpring Pharmaceutical Corporation), ketoconazole (commercially available as NIZORAL® from McNeil consumer Healthcare), clotrimazole (LOTRAMIN® or LOTRAMIN® available from Merck), AF®, and as CANESTEN® available from Bayer), econazole, omoconazole, bifonazole, butoconazole, fenticonazole, isoconazole, oxiconazole, sertaconazole (commercially available as ERTACZO® from OrthoDematologics), sulconazole, or tioconazole; triazole antifungals, such as fluconazole, itraconazole, isavuconazole, ravuconazole, posaconazole, voriconazole, terconazole, or albaconazole; thiazole antifungals (e.g., abafungin), allylamine antifungals (e.g., terbinafine (commercially available as LAMISIL® from Novartis Consumer Health, Inc.), naftifine (commercially available as NAFTIN® from Merz Pharmaceuticals), or butenafine (LOTRAMIN® from Merck). ULTRA®), echinocandin antifungal agents (e.g., anidulafungin, caspofungin, or micafungin), poligodial, benzoic acid, ciclopirox, tolnaftate (e.g., from MDS Consumer Care, Inc.(commercially available as TINACTIN® from Agrochemicals, Inc.), undecylenic acid, flucytosine, 5-fluorocytosine, griseofulvin, haloprogin, caprylic acid, and any combination thereof.

[0091]

[0084] Preservatives suitable for use in conjunction with the cellulose ester plastics described herein, in some embodiments, may include, but are not limited to, benzoates, parabens (e.g., the propyl-4-hydroxybenzoate series), and the like, or any combination thereof.

[0092] Pigments and dyes suitable for use with the cellulose ester plastics described herein, in some embodiments, include, but are not limited to, vegetable dyes, titanium dioxide, silicon dioxide, tartrazine, E102, phthalocyanine blue, phthalocyanine green, quinacridone, perylenetetracarboxylic acid di-imide, dioxazine, perinone disazo pigments, anthraquinone pigments, carbon black, metal powders, iron oxides, ultramarine, calcium carbonate, kaolin clay, aluminum hydroxide, barium sulfate, zinc oxide, aluminum oxide, CARTASOL® dyes (cationic dyes, available from Clariant Services) in liquid and / or granular form (e.g., CARTASOL® Brilliant Yellow K-6G Fluid, CARTASOL® Yellow K-4GL Fluid, CARTASOL® Yellow K-GL Fluid, CARTASOL® Orange K-3GL Fluid, CARTASOL® Scarlet K-2GL Fluid, CARTASOL® Red Fluid ... CARTASOL® Blue K-3BN Fluid, CARTASOL® Blue K-5R Fluid, CARTASOL® Blue K-RL Fluid, CARTASOL® Turquoise K-RL Fluid / Granules, CARTASOL® Brown K-BL Fluid), FASTUSOL® dyes (auxochromes, available from BASF) (e.g., Yellow 3GL, Fastusol C Blue 74L), and the like, as well as any derivatives thereof, and any combination thereof.

[0093]

[0086] In some embodiments, pigments and dyes suitable for use with the cellulose ester plastics described herein may be food grade pigments and dyes. Examples of food grade pigments and dyes, in some embodiments, may include, but are not limited to, vegetable dyes, titanium dioxide, and the like, or any combination thereof.

[0094]

[0087] Antioxidants, in some embodiments, can mitigate oxidation and / or chemical degradation of the cellulose ester plastics described herein during storage, shipping, and / or performance. Antioxidants suitable for use with the cellulose ester plastics described herein, in some embodiments, may include, but are not limited to, anthocyanins, ascorbic acid, glutathione, lipoic acid, uric acid, resveratrol, flavonoids, carotenes (e.g., beta-carotene), carotenoids, tocopherols (e.g., alpha-tocopherol, beta-tocopherol, gamma-tocopherol, or delta-tocopherol), tocotrienols, tocopherol esters (e.g., tocopherol acetate), ubiquinol, gallic acid, melatonin, secondary aromatic amines, benzofuranones, hindered phenols, polyphenols, hindered amines, organophosphorus compounds, thioesters, benzoates, lactones, hydroxylamines, butylated hydroxytoluene ("BHT"), butylated hydroxyanisole ("BHA"), hydroquinone, and the like, or any combination thereof.

[0095] In some embodiments, antioxidants suitable for use with the cellulose ester plastics described herein may be food grade antioxidants. Examples of food grade antioxidants, in some embodiments, may include, but are not limited to, ascorbic acid, vitamin A, tocopherol, tocopherol esters, beta-carotene, flavonoids, BHT, BHA, hydroquinone, and the like, or any combination thereof. EXAMPLES

[0096] The following examples were conducted to demonstrate some of the benefits and advantages of the present disclosure. Example 1

[0090] In a similar manner to the process shown in Figure 1 and described above, cellulose acetate flakes and a plasticizer were combined in an extruder. The plasticizer was triacetin and was added at two different locations along the extruder. The final composition was then tested for mechanical properties with the following results: During the process, some of the plasticizer was liberated during the process.

[0097] The compositions were subjected to the following tests (using the latest versions of standardized tests):

[0098] [Table 1]

[0099] The following samples were produced. The table below lists the amount of plasticizer ("Pz") that was added at a first location. An additional amount of plasticizer was added at a second downstream location to provide the final plasticizer dosage.

[0100] [Table 2]

[0101] The samples were then subjected to gel analysis testing with the following results:

[0102] [Table 3]

[0103] Below are the results for various physical properties.

[0104] [Table 4]

[0105] [Table 5]

[0106] Example 2 The cellulose acetate flakes and plasticizer were combined in an extruder similar to the process described in Example 1. The following samples were prepared:

[0107] [Table 6]

[0108] The above sample numbers 12-16 were then subjected to gel analysis testing and compared to a control sample in which all of the plasticizer was added at once. The following results were obtained:

[0109] [Table 7]

[0110]

[0092] These and other modifications and variations to the present invention may be practiced by those skilled in the art without departing from the spirit and scope of the present invention, as more particularly described in the appended claims. Moreover, it should be understood that aspects of the various embodiments may be interchanged, either in whole or in part. Moreover, those skilled in the art will appreciate that the above description is for illustrative purposes only, and is not intended to limit the invention, as further described in such appended claims.

Claims

1. 1. A method for producing a polysaccharide ester polymer product, comprising: feeding polysaccharide ester polymer particles into a heated extrusion device, the heated extrusion device defining a heated barrel having a length; after the polysaccharide ester polymer particles have been heated, combining the polysaccharide ester particles with a first amount of a first plasticizer in the heated extrusion device to form a blend of polysaccharide ester polymer and a first plasticizer; combining the blend of polysaccharide ester polymer particles and a first plasticizer with a second amount of a second plasticizer in the heated extrusion device downstream of where the polysaccharide ester polymer particles were combined with the first plasticizer; discharging the plasticized polysaccharide ester polymer product from said heated extrusion device; A method comprising:

2. 2. The method of claim 1, wherein the first plasticizer is added to the plasticized polysaccharide ester polymer product in a weight ratio relative to the second plasticizer of about 1:1 to about 1:20, such as about 1:2 to about 1:12, such as about 1:2 to about 1:

7.

3. The method of claim 1 or 2, wherein the first plasticizer and the second plasticizer are the same.

4. The method of claim 1 or 2, wherein the first plasticizer is a different plasticizer than the second plasticizer.

5. The method of claim 1 , wherein the polysaccharide ester polymer comprises a cellulose ester polymer.

6. 6. The method according to claim 1, wherein the total amount of plasticizer contained in the plasticized polysaccharide ester polymer product is greater than about 18% by weight, such as greater than about 20% by weight, for example greater than about 22% by weight, for example about 24% by weight, and generally less than about 40% by weight, for example less than about 30% by weight.

7. 7. The method of claim 1, wherein the polysaccharide ester polymer particles are in the form of flakes or granular flakes.

8. 8. The method of any one of claims 1 to 7, wherein greater than about 50% by weight of the polysaccharide ester polymer particles have a particle size greater than 850 microns as measured according to a sieve test.

9. 9. The method of claim 1, wherein the polysaccharide ester polymer particles are unground.

10. 10. The method of claim 1, wherein the plasticizer is preheated prior to contact with the polysaccharide ester polymer particles.

11. 11. The method of any one of claims 1 to 10, wherein the polysaccharide ester polymer and plasticizer are melt processed into pellets or strands.

12. The first plasticizer and the second plasticizer are selected from the group consisting of tris(chloroisopropyl)phosphate, tris(2-chloro-1-methylethyl)phosphate, glycerin, monoacetin, triethyl citrate, acetyl triethyl citrate, phthalate, adipate, polyethylene glycol, triacetin, diacetin, trimethyl phosphate, triethyl phosphate, tributyl phosphate, triphenyl phosphate, tributyl-o-acetyl citrate, dibutyl tartrate, ethyl o-benzoyl benzoate, n-ethyl toluene. sulfonamide, o-cresyl p-toluenesulfonate, aromatic diols, substituted aromatic diols, aromatic ethers, tripropionin, tribenzoin, glycerol esters, glycerol tribenzoate, glycerol acetate benzoate, polyethylene glycol, polyethylene glycol esters, polyethylene glycol diesters, di-2-ethylhexyl polyethylene glycol esters, glycerol esters, diethylene glycol, polypropylene glycol, polyglycol diglycidyl ether, dimethyl sulfoxide, N- Methylpyrrolidinone, propylene carbonate, C1-C20 dicarboxylic acid esters, dibutyl maleate, dioctyl maleate, resorcinol monoacetate, catechol, catechol esters, phenols, epoxidized soybean oil, castor oil, linseed oil, epoxidized linseed oil, polyethylene glycol-based bifunctional glycidyl ethers, alkyl lactones, phospholipids, 2-phenoxyethanol, acetylsalicylic acid, acetaminophen, naproxen, imidazole, triethanolamine, benzoic acid, benzyl benzoate, salicylic acid, benzoic ... butylated hydroxybenzoic acid, 4-hydroxybenzoic acid, propyl 4-hydroxybenzoate, methyl 4-hydroxybenzoate, ethyl 4-hydroxybenzoate, benzyl 4-hydroxybenzoate, glyceryl tribenzoate, neopentyl dibenzoate, triethylene glycol dibenzoate, trimethylolethane tribenzoate, butylated hydroxytoluene, butylated hydroxyanisole, sorbitol, xylitol, ethylenediamine, piperidine, piperazine, hexamethylenediamine, triazine, triazole, pyrrole,or a mixture thereof.

13. 13. The method of any one of claims 1 to 12, wherein the plasticizer comprises triacetin, polyethylene glycol, or a mixture thereof.

14. 14. The method of any one of claims 1 to 13, wherein the polysaccharide ester polymer comprises predominantly cellulose diacetate.

15. 15. The method of any one of claims 1 to 14, wherein the polysaccharide ester polymer product further comprises at least one additive, the at least one additive comprising an antioxidant, a stabilizer, an organic acid, an oil, a filler particle, a glass fiber, a pigment, a bio-based polymer other than a cellulose ester, a biodegradability enhancer, or a mixture thereof.

16. 16. The method of claim 15, wherein the at least one additive is compounded with the polysaccharide ester polymer to form a masterbatch, and the masterbatch is fed into the heated extrusion device along with the polysaccharide ester polymer particles.

17. 17. The method of any one of claims 1 to 16, wherein the polysaccharide ester polymer product further comprises an inorganic filler, the inorganic filler comprising talc, calcium carbonate, a metal oxide, mica, or a mixture thereof.

18. 18. The method of any one of claims 1 to 17, wherein the polysaccharide ester polymer product further comprises a colorant, the colorant comprising an organic dye, an inorganic dye, a pigment, or a mixture thereof.

19. 19. The method of any one of claims 1 to 18, wherein the polysaccharide ester polymer particles are fed to the heated extrusion device at a moisture content of less than about 8 wt%, such as less than about 4 wt%, for example less than about 2 wt%, for example less than about 1 wt%.

20. 20. The method of any one of claims 1 to 19, wherein a third amount of a third plasticizer is provided to the heated extrusion device downstream of the second plasticizer.

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