A composition containing a cellulose ester polymer comprising a melt strength improver

Abstract

A polymer composition is provided that includes a cellulose ester polymer combined with at least one salt additive. The salt additive can be combined with the cellulose ester polymer to reduce the melt flow rate of the polymer and improve the melt processability of the polymer in order to form a molded article.

Description

Technical Field

[0001] Cross - reference to Related Applications This application claims priority based on U.S. Provisional Patent Application No. 63 / 391,079, filed on July 21, 2022, which is incorporated herein by reference.

Background Art

[0002] Every year, the global production volume of plastics continues to increase. More than half of the total amount of plastics produced each year is used in the production of plastic bottles, containers, beverage straws, and other disposable items. Disposable plastic items, including plastic beverage bottles that have been discarded, typically are not recycled and ultimately are landfilled. In addition, many of these items are not properly disposed of and ultimately end up in rivers, lakes, and oceans around the world.

[0003] From the above perspective, those skilled in the art have been attempting to produce plastic articles made of 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] In the past, cellulose esters have been proposed as an alternative to some petroleum - based polymers or plastics. For example, cellulose esters are considered to be generally environmentally friendly polymers because they are recyclable, degradable, and derived from renewable resources such as wood pulp. However, problems have occurred in the melt processing of cellulose ester polymers such as cellulose acetate polymers. The polymer materials are relatively hard and have relatively poor elongation characteristics.

[0005] From the above perspective, there is currently a need for cellulose ester polymers and / or cellulose ester polymer compositions having improved melt - processing characteristics in order to form molded articles having excellent mechanical and physical properties.

SUMMARY OF THE INVENTION

MEANS FOR SOLVING THE PROBLEM

[0006] Generally, the present disclosure relates to a polysaccharide ester polymer composition, particularly a cellulose ester polymer composition, having improved melt processing characteristics. The polymer compositions of the present disclosure are also well suited for forming molded articles having desired mechanical properties. In addition, the polymer compositions of the present disclosure can be formulated to have excellent biodegradable properties.

[0007] In one embodiment, the present disclosure relates to a polymer composition comprising a cellulose ester polymer. The cellulose ester polymer can be present in the composition in an amount greater than about 40% by weight. The cellulose ester polymer is optionally blended with a plasticizer. According to the present disclosure, the polymer composition further contains a salt additive that provides cationic ions to the polymer composition. The salt additive is present in an amount sufficient to reduce the melt flow rate of the polymer composition by about 20% relative to an equivalent polymer composition that does not contain the salt additive. The salt additive can include, for example, polyvalent cations having a valence state of +2 or +3. The salt additive can include metal salts such as calcium salts, iron salts, aluminum salts, zinc salts, cobalt salts, manganese salts, or magnesium salts. Without particular limitation and for merely illustrative purposes, the salt additive can be, for example, calcium acetate, calcium hydroxide, magnesium acetate, lime, or a mixture thereof.

[0008] The salt additive can be present in the polymer composition in an amount of from about 1 ppm to about 10,000 ppm, such as from about 5 ppm to about 1,200 ppm, from about 10 ppm to about 800 ppm. In various embodiments, the salt additive can be present in the polymer composition in an amount sufficient to reduce the melt flow rate of the composition by more than about 30%, such as more than about 40%, more than about 50%, more than about 60%, more than about 70%, more than about 80%. For example, the melt flow rate of the polymer composition can be less than about 20 g / 10 min, such as less than about 18 g / 10 min, less than about 15 g / 10 min, less than about 12 g / 10 min, less than about 10 g / 10 min, less than about 8 g / 10 min when tested at 210 °C and a load of 2.16 kg.

[0009] In one embodiment, the cellulose ester polymer contained in the polymer composition has a relatively high initial melt flow rate, which can then be reduced when combined with the salt additive. Although not understood, the salt additive can cause ionic crosslinking of the cellulose ester polymer, which is thought to result in an increase in the melt flow rate. In a particular embodiment, the cellulose ester polymer has an acetyl value of from about 48% to about 56%, such as less than 53%, less than 54%.

[0010] In addition to reducing the melt flow rate, the salt additive can also provide various other benefits and advantages. For example, in one embodiment, the salt additive can be present in the polymer composition in an amount sufficient to reduce the L * value of an article formed from the polymer composition.

[0011] In one aspect, the cellulose ester polymer can be present in the polymer composition in an amount of about 55 wt% to about 95 wt%, and the plasticizer can be present in an amount of about 5 wt% to about 40 wt%. Plasticizers that can be incorporated into the polymer composition include tris(chloroisopropyl) phosphate, tris(2-chloro-1-methylethyl) phosphate, glycerin, monoacetin, triethyl citrate, acetyltriethyl citrate, phthalate, adipate, polyethylene glycol, triacetin, diacetin, trimethyl phosphate, triethyl phosphate, tributyl phosphate, triphenyl phosphate, tributyl o-acetyl citrate, dibutyl tartrate, ethyl o-benzoylbenzoate, n-ethyltoluenesulfonamide, o-cresyl p-toluenesulfonate, aromatic diol, substituted aromatic diol, polycaprolactone diol, aromatic ether, tripropionin, tribenzoin, glycerin ester, glycerol tribenzoate, glycerol acetate benzoate, polyethylene glycol, polyethylene glycol ester, polyethylene glycol diester, di-2-ethylhexyl polyethylene glycol ester, glycerol ester, diethylene glycol, polypropylene glycol, polyglycol diglycidyl ether, dimethyl sulfoxide, N-methylpyrrolidinone, propylene carbonate, C1-C20 dicarboxylic acid ester, di-butyl maleate, di-octyl maleate, resorcinol monoacetate, catechol, catechol ester, phenol, epoxidized soybean oil, castor oil, linseed oil, epoxidized linseed oil, bifunctional glycidyl ether based on polyethylene glycol, alkyl lactone, phospholipid, 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,Examples include butylated hydroxytoluene, butylated hydroxyanisole, sorbitol, xylitol, ethylenediamine, piperidine, piperazine, hexamethylenediamine, triazine, triazole, pyrrole, and mixtures thereof.

[0012] In one aspect, the plasticizer contained in the polymer composition is triacetin, polyethylene glycol, polycaprolactone diol, or a mixture thereof. The cellulose ester polymer can, in one aspect, consist essentially of cellulose diacetate.

[0013] The cellulose ester polymer composition can also contain various other additives and components. For example, the composition can further contain antioxidants, stabilizers, organic acids, oils, filler particles, glass fibers, biobased polymers other than cellulose esters, biodegradation promoters, foaming agents, or mixtures thereof. The composition can also contain inorganic fillers such as talc, calcium carbonate, metal oxides, mica, or mixtures thereof. The polymer composition can also contain colorants that are dyes, pigments, or mixtures thereof.

[0014] In one embodiment, the polymer composition is combined in a heated extruder or mixer and then extruded into strands that can then be cut into pellets. Various different molded articles can then be produced using the pellets. By way of example, the polymer composition can be used in the manufacture of beverage holders, drinking straws, pods for hot beverages, automotive interior parts, household appliances, medical device parts, packaging materials, and the like.

[0015] Other features and aspects of the present disclosure are discussed in more detail below.

[0016] A complete and enabling disclosure of the present disclosure is set forth more specifically below in this specification with reference to the accompanying drawings.

Brief Description of the Drawings

[0017]

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DETAILED DESCRIPTION OF THE INVENTION

[0018] The repeated use of reference numerals in this specification and the drawings is intended to represent the same or similar features or elements of the present invention.

[0019] It should be understood by those skilled in the art that this discussion is merely illustrative of exemplary embodiments and is not intended to limit the broader aspects of the present disclosure.

[0020] Generally, the present disclosure relates to a polymer composition containing a polysaccharide ester polymer such as a cellulose ester polymer having improved melt processing characteristics. Molded articles made from this polymer composition can have improved physical properties. Additionally, the polymer compositions of the present disclosure can be formulated to have higher sustainability and faster biodegradability than conventional cellulose ester polymer products. The polymer composition can be used to form all different types of products using any suitable molding technique such as extrusion molding, injection molding, etc. The polymer compositions of the present disclosure are particularly well formulated for use in any of the above processes.

[0021] In one aspect, the polymer composition of the present disclosure relates to a polymer composition containing a cellulose ester polymer having a carefully controlled degree of acetylation in combination with a relatively low melt flow rate, or in combination with various other properties. In other aspects, the polymer compositions of the present disclosure contain a cellulose ester polymer such as a cellulose acetate polymer in combination with a salt additive and optionally a plasticizer. The salt additives of the present disclosure are combined with the cellulose ester polymer in an amount sufficient to reduce the melt flow rate of the polymer composition. The salt additive can impart cationic ions to the polymer composition. Although not understood, the salt additive is thought to result in ionic cross-linking of the cellulose ester polymer that reduces the melt flow rate.

[0022] For example, the salt additive can be combined with the cellulose ester polymer in an amount sufficient to reduce the melt flow rate of the polymer composition and / or the cellulose ester polymer by more than about 20%, such as more than about 30%, more than about 40%, more than about 50%, more than about 60%, more than about 70%, more than about 80%. The melt flow rate can be reduced, for example, by more than about 90%, more than about 95%, etc., and up to about 99.8%.

[0023] Any suitable cellulose ester polymer can be incorporated into the polymer compositions of the present disclosure. In one aspect, the cellulose ester polymer is cellulose acetate.

[0024] Cellulose acetate can be formed by esterifying cellulose after activating the cellulose with acetic acid. Cellulose can be obtained from a number of types of cellulosic materials including, but not limited to, plant-derived biomass, corn stover, sugarcane stems, bagasse and sugarcane residues, rice straw and wheat straw, agricultural grasses, hardwoods, hardwood pulp, softwoods, softwood pulp, cotton linters, switchgrass, bagasse, herbs, recycled paper, waste paper, wood chips, pulp and paper waste, waste wood, thinned wood, willow, poplar, perennial grasses (e.g., Gramineae grasses), bacterial cellulose, seed coats (e.g., soybeans), corn stalks, rice husks, and other forms of wood, bamboo, soybean hulls, bast fibers such as kenaf, jute, flax and hemp, agricultural residues, agricultural waste, livestock excrement, microbial, algal cellulose, seaweed, and all other materials directly or ultimately derived from plants. Such cellulosic raw materials are preferably processed into pellets, chips, clips, sheets, milled fibers, powder form, or other forms to be in a form suitable for further purification.

[0025] Suitable cellulose esters for use in the production of the compositions of the present disclosure can, in some embodiments, include, but are not limited to, C1-C 20 aliphatic esters (e.g., acetate, propionate or butyrate), functional C1-C 20 aliphatic esters (e.g., succinate, glutarate, maleate), aromatic esters (e.g., benzoate or phthalate), substituted aromatic esters, etc., derivatives of any of these, and combinations of any of these, and can have ester substituents.

[0026] The cellulose acetate used in the composition can be diacetate cellulose or triacetate cellulose. In one embodiment, the cellulose acetate includes primary diacetate cellulose. For example, the cellulose acetate can contain less than 1% by weight of triacetate cellulose, such as less than 0.5% by weight of triacetate cellulose. The diacetate cellulose can constitute more than 90% by weight of the cellulose acetate, such as more than 95% by weight of the cellulose acetate, more than 98% by weight of the cellulose acetate, more than 99% by weight of the cellulose acetate.

[0027] Typically, the cellulose acetate can have a molecular weight greater than about 10,000 g / mol, such as greater than about 20,000 g / mol, greater than about 30,000 g / mol, greater than about 40,000 g / mol, greater than about 50,000 g / mol. The molecular weight of the cellulose acetate is generally less than about 800,000 g / mol, such as less than about 600,000 g / mol, less than about 200,000 g / mol, less than about 150,000 g / mol, less than about 100,000 g / mol, less than about 90,000 g / mol, less than about 70,000 g / mol, less than about 50,000 g / mol. The above molecular weights refer to the average molecular weight. The molecular weight can be measured using gel permeation chromatography with polystyrene equivalents or standards.

[0028] The cellulose ester polymer or cellulose acetate can generally have an initial intrinsic viscosity of about 0.2 dL / g to about 2 dL / g, and all values in between are included in 0.1 dL / g increments.

[0029] The intrinsic viscosity can be measured by forming a 0.20 g / dL solution of the cellulose ester in 98 / 2 wt / wt acetone / water and measuring the flow times of the solution and the solvent at 30 °C in a #25 Cannon-Ubbelohde viscometer. Then, the intrinsic viscosity ("IV") can be measured using the modified Baker-Philippoff equation, which for this solvent system is Equation 1.

Equation

[0030] The cellulose ester polymer contained in the polymer composition can be characterized by its acetyl value or degree of acetylation measured in percentage. The acetyl value is related to the degree of substitution and provides information on the amount of acetic acid released from the cellulose ester polymer by saponification. The acetyl value can be measured according to ASTM test D871-96(2004). In one embodiment, ASTM test D871-96 can be modified by replacing acetyl (molecular weight 42) with acetic acid (molecular weight 60) in the calculation of the acetyl value.

[0031] Generally, the cellulose ester polymer can have an acetyl value of about 48% to about 68% (the combined ratio of acetic acid), and all values in between are included in 0.1% units. In one aspect, the acetyl value can be more than about 54%, such as more than about 55%, more than about 56%, and generally less than about 65%, such as less than about 63%.

[0032] In certain embodiments, the cellulose ester polymer has a relatively low acetyl value. For example, the cellulose ester polymer can have an acetyl value of greater than about 48%, such as greater than about 49%, greater than about 50%, greater than about 51%, and less than about 56%, such as less than about 55%, less than about 54%, less than about 53%. Conventionally, cellulose ester polymers with relatively low acetyl values have been difficult to melt process and have been formed into molded articles using injection molding, blow molding, etc. Cellulose ester polymers with relatively low acetyl values tend to have a very high melt flow rate when combined with plasticizers. A high melt flow rate can pose problems that can affect not only the ability to shape the composition into a product, but also the stability of the final product. According to the present disclosure, however, cellulose ester polymers with relatively low acetyl values can be combined with salt additives to significantly and dramatically reduce the melt flow rate without compromising any of the other properties of products made from the cellulose ester polymer or polymer composition. In fact, products made from cellulose ester polymers with relatively low acetyl values according to the present disclosure can be biodegraded more rapidly compared to products made from cellulose ester polymers with high acetyl values.

[0033] In certain embodiments, for example, a polymer composition containing a cellulose ester polymer having a relatively low acetyl value as described above and combined with a plasticizer in an amount of about 5% to about 40% by weight, such as an amount of about 12% to about 28% by weight, can have a melt flow rate of less than about 20 g / 10 min, such as less than about 18 g / 10 min, less than about 15 g / 10 min, less than about 12 g / 10 min, less than about 10 g / 10 min, less than about 8 g / 10 min, when tested at a temperature of 210°C and a load of 2.16 kg. As used herein, the melt flow rate is measured at a temperature of 210°C and a load of 2.16 kg in accordance with ASTM test D1238-13, unless otherwise specified.

[0034] Other cellulose ester polymer compositions formulated in accordance with the present disclosure can also have a melt flow rate of less than about 20 g / 10 min, such as less than about 18 g / 10 min, less than about 15 g / 10 min, less than about 12 g / 10 min, less than about 10 g / 10 min, less than about 8 g / 10 min, less than about 6 g / 10 min, less than about 4 g / 10 min, less than about 2 g / 10 min, when tested at 210 °C and a load of 2.16 kg.

[0035] Typically, cellulose ester polymers are present in the polymer composition in an amount of about 15 wt% to about 95 wt%, all inclusive in 1 wt% increments therebetween. Cellulose acetate is generally present in the polymer composition in an amount greater than about 15 wt%, such as greater than about 25 wt%, greater than about 35 wt%, greater than about 45 wt%, greater than about 55 wt%, greater than about 65 wt%, greater than about 75 wt%, greater than about 85 wt%. Cellulose acetate is generally present in the polymer composition in an amount less than about 90 wt%, such as less than about 85 wt%, less than about 75 wt%, less than about 70 wt%, less than about 65 wt%.

[0036] According to the present disclosure, the polysaccharide ester polymer or cellulose ester polymer is combined with at least one salt additive. As noted above, the salt additive can be added to the polymer composition in an amount sufficient to reduce the melt flow rate of the composition. The salt additive can also affect various other properties of the polymer composition or a molded article made from the composition. For example, it is believed that combining a cellulose ester polymer with a salt additive can also increase mechanical strengths such as tensile strength and tensile modulus. It is believed that adding the salt additive can also increase the deflection temperature under load (DTUL) of the polymer composition.

[0037] In one aspect, the salt additive contained in the polymer composition is a salt capable of providing a cationic ion that combines with the cellulose ester polymer. In one embodiment, the salt additive includes a salt having a +2 or +3 cation. The salt additive can be a metal salt in one embodiment. The salt additive can be, for example, a magnesium salt, a calcium salt, an iron salt, an aluminum salt, a zinc salt, a cobalt salt, or a manganese salt. In one aspect, the salt additive is water-soluble at 25 °C or dissociates at least partially in water. The salt additive can be an inorganic salt or an organic salt. As used herein, a water-soluble solute is water-soluble if it can be dissolved in more than 1 gram per 100 ml of water at 25 °C.

[0038] Examples of salt additives that can be used according to the present disclosure include calcium acetate, ferrous acetate, ferric acetate, magnesium acetate, zinc acetate, cobalt acetate, manganese acetate, calcium hydroxide, magnesium hydroxide, lime, or mixtures thereof. Other examples of calcium salts that can be used include calcium sulfate, calcium bicarbonate, calcium bromate, calcium bromide, calcium chloride, calcium nitrate, calcium perchlorate, calcium propionate, calcium carboxylate, calcium benzoate, calcium aromatic carboxylate, magnesium acetate, magnesium bromide, magnesium chlorate, magnesium nitrate, magnesium perchlorate, magnesium sulfate, magnesium thiosulfate, calcium citrate, calcium gluconate, calcium lactate, zinc acetate, cobalt acetate, manganese acetate, etc. Combinations of any of the above salts can also be used.

[0039] In one embodiment, the salt additive has a neutral to acidic pH. For example, the salt additive can have a pH of less than about 8, such as less than about 7.5, less than about 7, and greater than about 5, such as greater than about 5.5, greater than about 6, greater than about 6.5 when combined with water.

[0040] The amount of salt additive incorporated into the polymer composition can depend on various factors including the type and amount of cellulose ester polymer present, the type and amount of plasticizer present, and the specific salt additive selected. Typically, one or more salt additives are incorporated into the polymer composition in an amount greater than about 1 ppm, such as greater than about 5 ppm, greater than about 10 ppm, greater than about 20 ppm, greater than about 30 ppm, greater than about 40 ppm, greater than about 50 ppm, greater than about 75 ppm, greater than about 100 ppm, greater than about 150 ppm, greater than about 200 ppm, greater than about 250 ppm, greater than about 300 ppm, greater than about 350 ppm, greater than about 400 ppm, greater than about 500 ppm. One or more salt additives are generally present in the polymer composition in an amount less than about 10,000 ppm, such as less than about 8,000 ppm, less than about 6,000 ppm, less than about 4,000 ppm, less than about 2,000 ppm, less than about 1,000 ppm, less than about 800 ppm.

[0041] The method by which one or more salt additives are incorporated into the polymer composition can also vary depending on the particular application. In one embodiment, the salt additive can first be combined with the cellulose ester polymer before being blended with one or more plasticizers. In other embodiments, one or more salt additives can be combined with the cellulose ester polymer together with the plasticizer. For example, one or more salt additives can be added to an extruder into which the different components are being extruded.

[0042] In one embodiment, an aqueous solution containing one or more salt additives is combined with a cellulose ester polymer. For example, it is possible to contact cellulose ester particles or flakes with an aqueous solution containing one or more salt additives. Alternatively, it is possible to add an aqueous solution containing one or more salt additives to an extruder during extrusion molding. The aqueous solution can generally contain one or more salt additives in an amount from about 50 ppm to about 50,000 ppm, inclusive in 1 ppm increments therebetween. For example, in one embodiment, the aqueous solution can contain one or more salt additives at a concentration from about 50 ppm to about 2,000 ppm. In alternative embodiments, higher concentrations of one or more salt additives can be incorporated into the aqueous solution in amounts such as from about 2,000 ppm to about 20,000 ppm. When applied in the form of an aqueous solution to a cellulose ester polymer, the amount of salt additive incorporated into the resulting polymer composition is generally less than the concentration contained in the aqueous solution.

[0043] The polymer compositions of the present disclosure can optionally include one or more plasticizers. Plasticizers particularly suitable for use in the polymer compositions include triacetin, monoacetin, diacetin, and mixtures thereof. Other suitable plasticizers include tris(chloroisopropyl) phosphate, tris(2-chloro-1-methylethyl) phosphate, triethyl citrate, acetyltriethyl citrate, glycerin, or mixtures thereof. In alternative embodiments, the plasticizer can be polyethylene glycol. In yet other embodiments, the plasticizer can be polycaprolactone.

[0044] 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 toluenesulfonamide, o-cresyl p-toluenesulfonate, aromatic diols, substituted aromatic diols, aromatic ethers, tripropionin, tribenzoin, glycerin, glycerin esters, glycerol tribenzoate, glycerol acetate benzoate, polyethylene glycol esters, polyethylene glycol diesters, di-2-ethylhexyl polyethylene glycol ester, glycerol esters, diethylene glycol, polypropylene glycol, polyglycol diglycidyl ether, dimethyl sulfoxide, N-methylpyrrolidinone, propylene carbonate, C1-C20 dicarboxylic acid esters, dimethyl adipate (and other dialkyl esters), di-butyl maleate, di-octyl maleate, resorcinol monoacetate, catechol, catechol esters, phenol, epoxidized soybean oil, castor oil, linseed oil, epoxidized linseed oil, other vegetable oils, other seed oils, bifunctional glycidyl ethers based on polyethylene glycol, alkyl lactones (e.g., γ-valerolactone), alkyl phosphates, aryl phosphates, phospholipids, aromas (including those described herein, e.g., eugenol, cinnamyl alcohol, camphor, methoxyhydroxyacetophenone (acetovanillone), vanillin and ethyl vanillin), 2-phenoxyethanol, glycol ethers, glycol esters, glycol ester ethers, polyglycol ethers, polyglycol esters, ethylene glycol ethers, propylene glycol ethers, 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, polycaprolactone diol, etc., derivatives of any of these, and combinations of any of these are included.

[0045] In one aspect, the carbonate ester can be used as a plasticizer. Exemplary carbonate esters include, but are not limited to, propylene carbonate, butylene carbonate, diphenyl carbonate, phenylmethyl carbonate, dicresyl carbonate, glycerin carbonate, dimethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, isopropylphenyl 2-ethylhexyl carbonate, phenyl 2-ethylhexyl carbonate, isopropylphenyl isodecyl carbonate, isopropylphenyl tridecyl carbonate, phenyl tridecyl carbonate, etc., and combinations of any of these can be included.

[0046] In yet another aspect, the plasticizer can be a polyol benzoate. Exemplary polyol benzoates 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 of 1 to 8), and combinations of these. In some cases, tribenzoates such as glyceryl tribenzoate may be preferred. In some cases, the polyol benzoate can be a solid at 25°C and can have a water solubility of less than 0.05 g / 100 ml at 25°C.

[0047] The plasticizer can also be bio-based. For example, by using a bio-based plasticizer, it is possible to make the polymer composition suitable for contact with food. Bio-based plasticizers particularly suitable for use in the compositions of the present disclosure include alkyl ketal esters, non-petroleum-based hydrocarbon esters, bio-based polymers or oligomers (such as polycaprolactone), or mixtures thereof, having a number average molecular weight of 1000 or less.

[0048] In one aspect, the bio-based plasticizer is an alkyl ketal ester having a chemical structure corresponding to Structure I shown below. [Chemical formula] (Wherein a is from 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 are 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, and each Z is independently -O-, -NH- or -NR-, where R is a hydrocarbyl group or a substituted hydrocarbyl group).

[0049] The above plasticizer corresponds to the reaction product of a polyol, an amino alcohol or a polyamine with a certain 1,2- and / or 1,3-alkanediol ketal of an oxocarboxylic acid ester. In the present specification, the 1,2- and 1,3-alkanediol ketals of the oxocarboxylic acid ester are referred to as "alkyl ketal esters". It is possible to react up to 1 mole of alkyl ketal ester per equivalent of hydroxyl or amino group provided by the polyol, amino alcohol or polyamine. The polyol, amino alcohol or polyamine is most preferably bifunctional, but it is possible to use polyols, amino alcohols and polyamines having more than two hydroxyl and / or amino groups.

[0050] The values of x and y in Structure I will depend on the number of hydroxyl or amino groups in the polyol, amino alcohol or polyamine, the number of moles of alkyl ketal ester per mole of polyol, amino alcohol or polyamine, and the degree to which the reaction proceeds towards completion. The greater the amount of alkyl ketal ester, the smaller the value of y and the greater the value of x tend to be.

[0051] In Structure I, y is specifically from 0 to 2, and x is specifically at least 2. All a in Structure I are specifically from 2 to 12, more specifically from 2 to 10, more specifically from 2 to 8, more specifically from 2 to 6, more specifically from 2 to 4, and more specifically 2. All R 1 is specifically an alkyl group, specifically methyl. In some embodiments of Structure I, all Z are -O-, y is 0, and x is 2; these products correspond to the reaction of 2 moles of alkyl ketal ester with 1 mole of diol. In some other embodiments, all Z are -O-, y is 1, and x is 1; these products correspond to the reaction of 1 mole of alkyl ketal ester with 1 mole of diol.

[0052] In one embodiment, all b are 0. In other embodiments, all b are 1.

[0053] Certain compounds according to some structures I have the structure:

Chem.

Chem.

Chem.

Chem.

[0054] In other particular embodiments, R 6 corresponds to the residue after removing the hydroxyl groups of diethylene glycol, and the structure (Ib)

Chem.

[0055] In other particular embodiments, R 6 corresponds to the residue after removing the hydroxyl groups of 2-methyl-1,3-propanediol, and the structure (Ic)

Chem.

[0056] The compounds according to Structure I can be prepared by a transesterification reaction or an ester-aminolysis reaction of the corresponding polyol, amino alcohol or polyamine with the corresponding alkyl ketal ester. Alternatively, the compounds according to Structure I can be prepared by reacting an oxocarboxylic acid with a polyol, amino alcohol 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, polycaprolactone diol, etc.

[0057] Alkyl ketal ester plasticizers are particularly suitable for use in combination with one or more other plasticizers. For example, in one embodiment, the alkyl ketal ester plasticizer can be combined with a benzoate ester. The weight ratio of the two plasticizers can vary, such as about 1:10 to about 10:1, such as about 1:4 to about 4:1.

[0058] Other biobased plasticizers that can be incorporated into the polymer compositions of the present disclosure are non-petroleum hydrocarbon esters. For example, one example of a non-petroleum hydrocarbon ester is sold under the trade name HALLGREEN by Hall Star Company (Chicago, Illinois). The non-petroleum hydrocarbon ester plasticizer can contain a biobased content of, for example, greater than about 50 wt%, greater than about 70 wt%, such as greater than about 99 wt%. The esters can be obtained, for example, mainly from agricultural, forestry or marine materials and are therefore biodegradable. In one aspect, the non-petroleum hydrocarbon ester plasticizer has a specific gravity at 25 °C of about 1.16 or greater, such as about 1.165 or greater, about 1.17 or greater, about 1.74 or greater, and generally about 1.19 or less, such as about 1.185 or less, about 1.18 or less, about 1.78 or less. The non-petroleum hydrocarbon ester plasticizer can have an acid value of about 0.5 mg KOH / g to about 0.6 mg KOH / g, such as about 0.53 mg KOH / g to about 0.57 mg KOH / g.

[0059] In other aspects, the polymer composition contains a biobased plasticizer that is a biobased polyester, such as a biobased aliphatic polyester having a relatively low molecular weight. For example, the plasticizer can contain a biobased polyester polymer having a number average molecular weight of less than about 1000, less than about 900, such as less than about 800, and generally greater than about 500. In one embodiment, the biobased plasticizer is polycaprolactone having a number average molecular weight of 1000 or less. Alternatively, the biobased plasticizer can be a polyhydroxyalkanoate, such as polyhydroxybutyrate, having a number average molecular weight of 10,000 or less.

[0060] In one aspect, the plasticizer does not contain phthalates. In fact, the polymer composition can be formulated to be phthalate-free. For example, the phthalates can be present in the polymer composition in an amount of about 0.5% or less, such as an amount of about 0.1% or less.

[0061] Ordinary, one or more plasticizers can be present in the polymer composition in an amount of about 3% to about 40% by weight, such as in an amount of about 8% to about 35% by weight. Conventionally, however, a relatively large amount of plasticizer has been considered necessary to produce a melt processable cellulose acetate composition. However, the amount of plasticizer can be reduced without impairing the melt processing characteristics of the composition. For example, in one aspect, one or more plasticizers can be present in the polymer composition in an amount of about 15% or less, such as about 13% or less, about 10% or less, etc., such as about 17% or less, about 19% or less. One or more plasticizers are generally present in an amount of about 3% or more, such as about 5% or more.

[0062] Cellulose acetate can be present such that the weight ratio between cellulose acetate and one or more plasticizers to the plasticizer is from about 60:40 to about 95:5, such as from about 70:30 to about 90:10.

[0063] In addition to the polysaccharide ester polymer, one or more salt additives, and optionally one or more plasticizers, the polymer compositions of the present disclosure can contain a variety of other additives and components. For example, cellulose acetate, one or more plasticizers, and one or more salt additives can also be combined with one or more biobased polymers different from cellulose acetate and the one or more plasticizers. As used herein, a "biobased" polymer or plasticizer refers to a polymer, oligomer, or compound produced from at least partially renewable biomass sources such as plant materials or food waste. For example, a biobased polymer can be a polymer produced from greater than about 30% renewable resources, such as greater than about 40% renewable resources, greater than about 50% renewable resources, greater than about 60% renewable resources, greater than about 70% renewable resources, greater than about 80% renewable resources, greater than about 90% renewable resources. Biobased polymers should be distinguished from polymers derived from fossil resources such as petroleum. Biobased polymers can be bio-derived, which means that the polymer is derived from a biological source or is produced via a biological reaction such as fermentation or other microbial processes. Although cellulose ester polymers can be considered biobased polymers, the term herein refers to other biobased materials that can be combined with cellulose ester polymers. Biobased polymers can also be biodegradable.

[0064] In one aspect, the biobased polymer can be a polyester polymer such as an aliphatic polyester. Specific biobased polymers that can be incorporated into the polymer composition include polyhydroxyalkanoates, polylactic acid, polycaprolactone, or mixtures thereof.

[0065] In one aspect, at least one biobased polymer combined with cellulose acetate is a polyhydroxyalkanoate. Polyhydroxyalkanoates can be homopolymers or copolymers. Polyhydroxyalkanoates, also known as "PHA", are linear polyesters produced in nature by the bacterial fermentation of carbohydrates or lipids. It is possible to combine more than 100 different monomers in this family to yield materials with very different properties. Generally, these can be thermoplastic or elastomeric materials with melting points in the range of 40 to 180 °C. The most common type of PHA is PHB (poly-β-hydroxybutyrate). Poly(3-hydroxybutyrate) (PHB) is a type of natural thermoplastic polymer currently produced by microorganisms within the cell walls of a number of wild bacterial species or genetically engineered bacteria or yeasts. It is biodegradable and does not cause environmental problems after disposal, i.e., PHB-made articles can be composted.

[0066] One or more monomers used in the production of PHA can have a significant impact on the physical properties of the polymer. For example, PHA can be produced as crystalline, semi-crystalline or completely amorphous. For example, poly-4-hydroxybutyrate homopolymer can have a glass transition temperature of less than about -30 °C and can be completely amorphous without a distinct melting point temperature. Polyhydroxybutyrate-valerate copolymers can also be formulated to be semi-crystalline to amorphous with low stiffness characteristics.

[0067] Examples of monomer units that can be incorporated into PHA include 2-hydroxybutyrate, glycolic acid, 3-hydroxybutyrate (hereinafter referred to as 3HB in this specification), 3-hydroxypropionate (hereinafter referred to as 3HP in this specification), 3-hydroxyvalerate (hereinafter referred to as 3HV in this specification), 3-hydroxyhexanoate (hereinafter referred to as 3HH in this specification), 3-hydroxyheptanoate (hereinafter referred to as 3HH in this specification), 3-hydroxyoctanoate (hereinafter referred to as 3HO in this specification), 3-hydroxynonanoate (hereinafter referred to as 3HN in this specification), 3-hydroxydecanoate (hereinafter referred to as 3HD in this specification), 3-hydroxydodecanoate (hereinafter referred to as 3HDd in this specification), 4-hydroxybutyrate (hereinafter referred to as 4HB in this specification), 4-hydroxyvalerate (hereinafter referred to as 4HV in this specification), 5-hydroxyvalerate (hereinafter referred to as 5HV in this specification), and 6-hydroxyhexanoate (hereinafter referred to as 6HH in this specification). The 3-oxy acid monomers incorporated into PHA are (D) or (R) 3-oxy acid isomers, except for 3HP which has no chiral center.

[0068] In some embodiments, the PHA in the methods described herein is a homopolymer (here, all monomer units are the same). Examples of PHA homopolymers include poly-3-hydroxyalkanoate (e.g., poly-3-hydroxypropionate (hereinafter referred to as P3HP in this specification)), poly-3-hydroxybutyrate (hereinafter referred to as P3HB in this specification), and poly-3-hydroxyvalerate, poly-4-hydroxyalkanoate (e.g., poly-4-hydroxybutyrate (hereinafter referred to as P4HB in this specification)), poly-4-hydroxyvalerate (hereinafter referred to as P4HV in this specification)), or poly-5-hydroxyalkanoate (e.g., poly-5-hydroxyvalerate (hereinafter referred to as P5HV in this specification)).

[0069] In certain embodiments, the PHA can be a copolymer (containing two or more different monomer units), where the different monomers are randomly distributed in the polymer chain. Examples of PHA copolymers include poly 3-hydroxybutyrate-co-3-hydroxypropionate (hereinafter referred to as PHB3HP in this specification), poly 3-hydroxybutyrate-co-4-hydroxybutyrate (hereinafter referred to as P3HB4HB in this specification), poly 3-hydroxybutyrate-co-4-hydroxyvalerate (hereinafter referred to as PHB4HV in this specification), poly 3-hydroxybutyrate-co-3-hydroxyvalerate (hereinafter referred to as PHB3HV in this specification), poly 3-hydroxybutyrate-co-3-hydroxyhexanoate (hereinafter referred to as PHB3HH in this specification), and poly 3-hydroxybutyrate-co-5-hydroxyvalerate (hereinafter referred to as PHB5HV in this specification).

[0070] An example of a PHA having four different monomer units would be PHB-co-3HH-co-3HO-co-3HD or PHB-co-3-HO-co-3HD-co-3HDd. Typically, when PHB3HX has three or more monomer units, the 3HB monomer is at least 70% by weight of the total monomer amount, such as more than 90% by weight of the total monomer amount.

[0071] When present, one or more PHAs can be contained in the polymer composition in an amount of about 2% or more, such as about 3% or more, about 5% or more, about 7% or more, about 10% or more, about 12% or more, about 15% or more, about 18% or more. One or more PHAs generally are present in the polymer composition in an amount of about 30% or less, such as about 25% or less, about 20% or less, about 15% or less.

[0072] In addition to one or more PHAs, the polymer composition can contain various other biobased polymers such as polylactic acid or polycaprolactone. Polylactic acid is also known as "PLA" and is particularly suitable for combination with one or more PHAs. Polylactic acid polymers are generally hard and more rigid than PHAs, and can therefore be added to the polymer composition to further enhance the properties of the overall formulation.

[0073] Polylactic acid can generally be derived from monomer units of any isomer of lactic acid, such as L-lactic acid ("L-lactate"), D-lactic acid ("D-lactate"), meso-lactic acid, or mixtures thereof. The monomer units can also be formed from anhydrides of any isomer of lactic acid, including L-lactide, D-lactide, meso-lactide, or mixtures thereof. Such cyclic dimers of lactic acid and / or lactide can also be employed. Lactic acid can be polymerized using any known polymerization method, such as polycondensation or ring-opening polymerization. Small amounts of chain extenders (e.g., diisocyanate compounds, epoxy compounds or acid anhydrides) can also be employed. Polylactic acid can be a homopolymer or copolymer, such as those containing monomer units derived from L-lactic acid and monomer units derived from D-lactic acid. Although not essential, the content of one of the monomer units derived from L-lactic acid and the monomer units derived from D-lactic acid is preferably about 85 mol% or more, in some embodiments about 90 mol% or more, and in some embodiments about 95 mol% or more. A plurality of polylactic acids with different ratios of monomer units derived from L-lactic acid and monomer units derived from D-lactic acid can be blended in any proportion.

[0074] In a particular embodiment, the polylactic acid has the following general structure:

Chemical formula

[0075] Polylactic acid typically has a number average molecular weight (“Mn”) in the range of about 40,000 to about 160,000 grams / mole, in some embodiments about 50,000 to about 140,000 grams / mole, and in some embodiments about 80,000 to about 120,000 grams / mole. Similarly, the polymer also typically has a weight average molecular weight (“M w w”) in the range of about 80,000 to about 200,000 grams / mole, in some embodiments about 100,000 to about 180,000 grams / mole, and in some embodiments about 110,000 to about 160,000 grams / mole. The ratio of weight average molecular weight to number average molecular weight (“Mw / Mn”), i.e., the “polydispersity index”, is also relatively low. For example, the polydispersity index is typically in the range of about 1.0 to about 3.0, in some embodiments about 1.1 to about 2.0, and in some embodiments about 1.2 to about 1.8. The weight and number average molecular weights can be measured by methods known to those skilled in the art.

[0076] Polylactic acid can be present in the polymer composition in an amount of about 1% or more, such as about 3% or more, about 5% or more, and generally in an amount of about 20% or less, such as about 15% or less, about 10% or less, about 8% or less.

[0077] As described above, other biobased polymers that can be combined with cellulose acetate, alone or in combination with other biobased polymers, are polycaprolactones having a higher molecular weight than the polycaprolactone plasticizer. Polycaprolactone can be formulated to have a relatively low glass transition temperature, similar to PHA. The glass transition temperature can be, for example, less than about 10°C, such as less than about 5°C, less than about -20°C, and generally greater than about -60°C. The polymer can be made to be amorphous or semi-crystalline. The crystallinity of the polymer can be less than about 50%, such as less than about 25%.

[0078] Polycaprolactone can generally be formed to have a number average molecular weight of more than about 5,000, such as more than about 8,000, and generally less than about 15,000, such as less than about 12,000.

[0079] Polycaprolactone can be contained in the polymer composition in an amount of 2% or more, such as 3% or more, 5% or more, 7% or more, 10% or more, 12% or more, 15% or more, 18% or more. Polycaprolactone generally exists in the polymer composition in an amount of 30% or less, such as 25% or less, 20% or less, 15% or less.

[0080] Other bio-based polymers that can be incorporated into the polymer composition include polybutylene succinate, polybutylene adipate terephthalate, plasticized starch, other starch-based polymers, etc. In addition, the bio-based polymer can be a polyolefin or polyester polymer made from renewable resources. For example, such polymers include bio-based polyethylene, bio-based polybutylene terephthalate, etc.

[0081] In one aspect, an acid scavenger can also be present in the polymer composition. The acid scavenger can be a carbonate, an oxide, an amine, or a mixture thereof. Examples of acid scavengers include zinc oxide, magnesium oxide, sodium aluminum carbonate, aluminum silicate, hydrotalcite, or a mixture thereof. One or more acid scavengers can generally be present in the polymer composition in an amount of more than about 0.1% by weight, such as more than about 0.5% by weight, more than about 1% by weight, and generally less than about 2.5% by weight, such as less than about 2% by weight, less than about 1.5% by weight.

[0082] The polymer composition may also contain antioxidants, pigments, lubricants, plasticizers, antibacterial agents, antifungal agents, preservatives, flame retardants, and combinations thereof. Each of the above additives can 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.

[0083] Suitable flame retardants for use in combination with the cellulose ester plastics described herein include, in some embodiments, but are not limited to, silica, metal oxides, phosphates, catechol phosphates, resorcinol phosphates, borates, inorganic hydrates, aromatic polyhalides, etc., and combinations of any of these.

[0084] As antifungal agents and / or antibacterial agents suitable for use in combination with the cellulose ester plastics described in this specification, in some embodiments, but not limited to these, polyene antifungal agents (e.g., natamycin, rimocidin, filipin, nystatin, amphotericin B, candicidin, and hamycin), imidazole antifungal agents including miconazole (available from WellSpring Pharmaceutical Corporation as MICATIN®), ketoconazole (commercially available from McNeil consumer Healthcare as NIZORAL®), clotrimazole (commercially available from Merck as LOTRAMIN® and LOTRAMIN AF®, and from Bayer as CANESTEN®), econazole, omoconazole, bifonazole, butoconazole, fenticonazole, isoconazole, oxiconazole, sertaconazole (commercially available from OrthoDematologics as ERTACZO®), sulconazole, and tioconazole; triazole antifungal agents such as fluconazole, itraconazole, isavuconazole, ravuconazole, posaconazole, voriconazole, terconazole, and albaconazole, thiazole antifungal agents (e.g., abafungin), allylamine antifungal agents (e.g., terbinafine (commercially available from Novartis Consumer Health, Inc. as LAMISIL®), naftifine (commercially available from Merz Pharmaceuticals as NAFTIN®), and butenafine (commercially available from Merck as LOTRAMIN ULTRA®), echinocandin antifungal agents (e.g., anidulafungin, caspofungin, and micafungin), polygodial, benzoic acid, ciclopirox, tolnaftate (e.g., as TINACTIN® from MOS Consumer Care, Inc.Those commercially available), undecylenic acid, flucytosine, 5-fluorocytosine, griseofulvin, haloprogin, caprylic acid, and any combination thereof may be mentioned.

[0085] As preservatives suitable for use in combination with the cellulose ester plastics described herein, in some embodiments, but not limited to, benzoates, parabens (e.g., a series of propyl-4-hydroxybenzoates), etc., and any combination thereof may be mentioned.

[0086] Examples of pigments and dyes suitable for use in combination with the cellulose ester plastics described herein include, in some embodiments, but are not limited to, vegetable dyes, plant dyes, titanium dioxide, silicon dioxide, tartrazine, E102, phthalocyanine blue, phthalocyanine green, quinacridone, perylene tetracarboxylic diimide, 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 (liquid), CARTASOL® Yellow K-4G L (liquid), CARTASOL® Yellow K-GL (liquid), CARTASOL® Orange K-3GL (liquid), CARTASOL® Scarlet K-2GL (liquid), CARTASOL® Red K-3BN (liquid), CARTASOL® Blue K-5R (liquid), CARTASOL® Blue K-RL (liquid), CARTASOL® Turquoise K-RL (liquid / granular), CARTASOL® Brown K-BL liquid), FASTUSOL® dyes (auxochromes, manufactured by BASF) (e.g., Yellow 3GL, Fastusol C Blue 74L), derivatives of any of these, and combinations of any of these may be mentioned.

[0087] In some embodiments, the pigments and dyes suitable for use in combination with the cellulose ester plastics described herein can be food-grade pigments and dyes. Examples of food-grade pigments and dyes include, in some embodiments, but are not limited to, vegetable dyes, plant dyes, titanium dioxide, etc., and combinations of any of these may be mentioned.

[0088] The antioxidant can, in some embodiments, reduce the oxidation and / or chemical degradation of the cellulose ester plastics described herein during storage, transportation, and / or introduction. Antioxidants suitable for use in combination with the cellulose ester plastics described herein include, in some embodiments, but are not limited to, anthocyanin, ascorbic acid, glutathione, lipoic acid, uric acid, resveratrol, flavonoid, carotene (e.g., β-carotene), carotenoid, tocopherol (e.g., α-tocopherol, β-tocopherol, γ-tocopherol, and δ-tocopherol), tocotrienol, tocopherol ester (e.g., tocopherol acetate), ubiquinol, gallic acid, melatonin, secondary aromatic amine, benzofuranone, hindered phenol, polyphenol, hindered amine, organic phosphorus compound, thioester, benzoate, lactone, hydroxylamine, butylated hydroxytoluene ("BHT"), butylated hydroxyanisole ("BHA"), hydroquinone, etc., and any combination thereof.

[0089] In some embodiments, the antioxidant suitable for use in combination with the cellulose ester plastics described herein can be a food-grade antioxidant. Examples of food-grade antioxidants include, in some embodiments, but are not limited to, ascorbic acid, vitamin A, tocopherol, tocopherol ester, β-carotene, flavonoid, BHT, BHA, hydroquinone, etc., and any combination thereof.

[0090] In one embodiment, the polymer composition contains an antioxidant that includes a phosphorus compound, particularly a phosphite. For example, in one embodiment, the antioxidant can be a diphosphite. For example, in one embodiment, the antioxidant is a pentaerythritol diphosphite such as bis(2,4-dicumylphenyl)pentaerythritol diphosphite. The antioxidant can generally be present in the polymer composition in an amount of less than about 2 wt%, such as less than about 1 wt%, less than about 0.5 wt%, less than about 0.3 wt%. The antioxidant can generally be present in the polymer composition in an amount of more than about 0.05 wt%, such as more than about 0.08 wt%, more than about 0.1 wt%, more than about 0.13 wt%.

[0091] The polymer composition of the present disclosure can be formed into any suitable polymer article using any technique known in the art. For example, the polymer article can be formed from the polymer composition by extrusion molding, injection molding, blow molding, or the like.

[0092] In one aspect, a polymer composition containing cellulose acetate can be formulated such that the polymer composition has properties very similar to those of petroleum-based polymers such as polypropylene. By matching the physical properties of petroleum-based polymers, the polymer composition of the present disclosure is particularly suitable for replacing these polymers in many different end-use applications.

[0093] Examples of polymer articles that can be manufactured according to the present disclosure include drinking straws, beverage holders, automotive parts, knobs, door handles, household appliances, and the like.

[0094] For example, referring to FIG. 1, a beverage straw 10 that can be manufactured in accordance with the present disclosure is shown. Conventionally, beverage straws were typically manufactured from petroleum-based polymers such as polypropylene. However, the polymer composition of the present disclosure can be formulated to match the physical properties of polypropylene. Therefore, the beverage straw 10 can be manufactured in accordance with the present disclosure and can be completely biodegradable.

[0095] Referring to FIG. 2, a cup or beverage holder 20 that can also be manufactured in accordance with the present disclosure is shown. The cup 20 can be formed, for example, using injection molding or via any suitable thermoforming process. As shown in FIG. 7, the lid 22 of the cup 20 can also be manufactured from the polymer composition of the present disclosure. The lid can optionally include a pour spout 24 for pouring the beverage from the cup 20. In addition to lids for beverage holders, the polymer composition of the present disclosure can be used to form lids for all different types of containers, including food containers, packaging containers, storage containers, and the like.

[0096] In yet other embodiments, it is possible to manufacture a hot beverage pod 30 shown in FIG. 3 using the polymer composition. In addition to beverage pods, it is also possible to manufacture a plastic bottle 40 shown in FIG. 4, which can be a water cylinder or other sports beverage container, using the polymer composition.

[0097] Referring to FIG. 5, an automobile interior is illustrated. The automobile interior includes various automobile parts that can be manufactured in accordance with the present disclosure. Using the polymer composition, it is possible to manufacture, for example, an automobile part 50 that includes at least a portion of an interior door handle. The polymer composition can be used to manufacture a part of a steering column, such as an automobile part 60. Typically, the polymer composition can be used to mold any suitable decorative trim part or bezel, such as a trim part 70. In addition, it is possible to manufacture a knob or handle that can be used in the interior of a vehicle using the polymer composition.

[0098] The polymer composition is also highly suitable for the manufacture of cutlery such as forks, spoons and knives. For example, referring to FIG. 6, a disposable cutlery 80 is shown. The cutlery 80 includes a knife 82, a fork 84 and a spoon 86.

[0099] In yet another embodiment, it is possible to manufacture a storage container 90 shown in FIG. 8 using the polymer composition. The storage container 90 can be provided with a lid 94 that engages in combination with the edge of the bottom 92. The bottom 92 can define an internal volume for holding articles. The container 90 can be used to hold food or dry goods.

[0100] In yet another embodiment, the polymer composition can be formulated to manufacture a paper plate liner, an eyeglass frame, a driver's handle, or any other suitable part.

[0101] The cellulose ester composition of the present disclosure is also particularly suitable for use in the manufacture of medical devices including all different types of medical instruments. The cellulose ester composition is suitable, for example, for replacing other polymers such as conventionally used polycarbonate polymers. The cellulose ester composition of the present disclosure is not only biodegradable, but this composition has a unique "warm touch" during handling. Therefore, the composition is particularly suitable for constructing the housing of medical devices. When held or gripped, for example, the polymer composition retains heat and the device or instrument feels warmer than devices formed of other materials in the prior art. This feeling can bring particular comfort and comfort to people in need of medical support, and can also bring advantages to medical providers. In one aspect, the cellulose ester composition used in the manufacture of a housing for a medical device includes a plasticizer (such as triacetin), and a cellulose ester polymer optionally combined with other bio-based polymers. In addition, the composition can contain one or more colorants.

[0102] Referring to FIG. 9, for example, an inhaler 130 that can be formed from a cellulose ester polymer composition is shown. The inhaler 130 includes a housing 132 attached to a mouthpiece 134. A plunger 136 that houses a canister containing the composition to be inhaled is operatively linked to the housing 132. The composition may include a spray or a powder.

[0103] In use, the inhaler 130 administers a measured dose of a drug, such as an asthma medication, to a patient. The asthma medication may be suspended or dissolved in a propellant, or may be included in a powder. When the patient activates the inhaler to inhale the drug, a valve opens and the drug can be discharged from the mouthpiece. According to the present disclosure, the housing 132, the mouthpiece 134, and the plunger 136 can all be formed from the above polymer composition.

[0104] Referring to FIG. 10, other medical products that can be manufactured according to the present disclosure are shown. In FIG. 10, a medical syringe 140 is shown. The medical syringe 140 includes a housing 142 operatively linked to a plunger 144. The housing 142 can slide relative to the plunger 144. The medical syringe 140 may be provided with a spring. The medical syringe is for injecting a drug into a patient, typically into the thigh or buttock. The medical syringe can be either needleless or provided with a needle. When provided with a needle, typically the needle tip is hidden in the housing before injection. On the other hand, a needleless syringe can be provided with a pressurized gas cylinder that ejects the drug through the skin without using a needle. According to the present disclosure, the housing 142 and / or the plunger 144 can be formed from the above polymer composition.

[0105] The medical injector 140 shown in FIG. 10 can be used to inject insulin. Referring to FIG. 12, there is shown an insulin pump device 150 that can be provided with a housing 156 formed from the polymer composition of the present disclosure. The insulin pump device 150 can be provided with a pump in fluid communication with a tube 152 and a needle 154 for subcutaneous injection of insulin into a patient.

[0106] The polymer composition of the present disclosure can also be used in all different types of laparoscopic devices. Laparoscopic surgery refers to a surgical technique performed through an existing opening in the body or through one or more small incisions. Laparoscopic devices include different types of laparoscopes, needle holders, trocars, intestinal forceps, laryngoscopes, etc.

[0107] Referring to FIG. 11, for example, there is shown a laryngoscope 160 manufactured according to the present disclosure. The laryngoscope 160 includes a thin, flexible plastic tube having an optical fiber for visualizing the airway. The laryngoscope can be attached to a television camera to leave a permanent record of the examination. The laryngoscope 160 includes a housing 162 made of the polymer composition of the present disclosure. The laryngoscope 160 is for examination of the nose and pharynx. With a laryngoscope, a doctor can examine most of the inside of the nose, the eustachian tube opening, the pharyngeal tonsils, the pharynx, and the vocal cords.

[0108] As described above, the molded article can be injection molded or thermoformed. When thermoformed, the polymer composition can first be formed into a film and then thermoformed into an article.

[0109] During thermoforming, the film substrate is heated and then processed into a desired three-dimensional shape. The substrate can be formed on a male or female mold. Typically, there are mainly two types of thermoforming called vacuum forming and pressure forming. Both types of thermoforming utilize heat and pressure to form the film substrate into its final shape. In vacuum forming, the film substrate is placed on a mold and a vacuum is used to process the film substrate into a three-dimensional article. In pressure forming, pressure is optionally used in combination with a vacuum force to form the film substrate.

[0110] The use of thermoforming to manufacture three-dimensional articles has various advantages. For example, thermoforming enables the manufacture of all different types of shapes in a short required time. Design changes can also be made quickly and efficiently. Thermoforming can also be economical and can produce articles with an aesthetic appearance.

[0111] The temperature and pressure applied to the foamed substrate during the thermoforming process can vary depending on various different factors including the thickness of the foamed substrate and the type of product to be formed. Generally, thermoforming can be carried out at a temperature of about 75° to about 120°, such as about 75° to about 100°. However, it is also possible to use higher temperatures. As described above, the foamed substrate is also subjected to a pressure and / or suction force that presses the foamed substrate against the mold to conform the foamed substrate to the shape of the mold. Once formed, the three-dimensional article can be trimmed and / or polished as desired.

[0112] As described above, one or more salt additives in combination with a cellulose ester polymer can dramatically reduce the melt flow rate of the resulting polymer composition. In addition to improving the melt processing characteristics of the polymer composition, including the salt additive can also increase the tensile strength, increase the tensile modulus, and increase the deflection temperature of the composition. The use of one or more salt additives in the polymer composition is also thought to be able to improve the appearance of molded articles made of the polymer composition.

[0113] In one aspect, the improvement of surface characteristics can also be confirmed by the decrease in visual sensitivity (L * ). For example, a salt additive can cause the resulting composition to have an L * value lower than that of the same composition containing no salt additive and the same amount of cellulose ester polymer. For example, the salt additive can be combined with the cellulose ester polymer such that the resulting composition has an L * value lower than that of the same composition containing no salt additive and the same amount of cellulose ester polymer. For example, the L * value can be reduced by more than about 0.1%, such as more than about 0.3%, more than about 0.5%, more than about 0.8%, more than about 1%, etc.

[0114] As used herein, the CIE Lab color values L * , a * and b * are measured according to the color space defined by the International Commission on Illumination. The L * a * b * color space was standardized in 1976 by the Commission Internationale de l’Eclairage (CIE). The CIELab L * value used herein to define the darkness / brightness of the polymer composition is a unit of color measurement in the above CIE Lab system. Colors can be matched according to CIE Lab. In the L * a * b * color space, L * refers to the brightness represented by a numerical value.

[0115] The molded articles formed in accordance with the present disclosure can also have excellent transparency characteristics. The polymer compositions of the present disclosure can exhibit, for example, low haze characteristics. For example, the polymer composition can exhibit a haze of less than about 50%, such as less than about 35%, less than about 25%, less than about 20%, less than about 15%, less than about 10%, less than about 8%, less than about 5%, less than about 3%, less than about 2%, less than about 1%, less than about 0.8%, less than about 0.5%, less than about 0.4%, less than about 0.3%, less than about 0.2%. Generally, the polymer articles formed in accordance with the present disclosure can have their haze measured in accordance with ASTM Test D1003 (2013). The haze can be measured using any acceptable equipment in accordance with ASTM tests, including, for example, the BYK Gardner Haze-Gard 4725 instrument. The haze can be measured on test plaques, films formed in accordance with the present disclosure, or final thermoformed articles. The test plaques can have any suitable thickness, such as 1 mm, 2 mm, 3 mm, or 4 mm.

[0116] The present disclosure can be better understood with reference to the following examples.

Examples

[0117] Example 1 In accordance with the present disclosure, a cellulose ester polymer was combined with a plasticizer and different amounts of calcium acetate and tested for melt flow rate. Each sample contained a cellulose ester polymer having an acetyl value of about 52.6 and an intrinsic viscosity of 1.65 dL / g. Each sample contained triacetin in an amount of 24 wt% as a plasticizer. The following samples were formulated.

[0118]

Table 1

[0119] The above composition was extruded into pellets and then the melt flow rate was tested. The temperatures during extrusion were various. The melt flow rate was tested at 210 °C and a load of 2.16 kg. The following results were obtained.

[0120]

Table 2

[0121] As shown above, by adding a small amount of salt additive, the melt flow index was dramatically and unexpectedly reduced so that the melt processing of the composition became easier.

[0122] Example 2 The flake form cellulose ester polymer described in Example 1 was washed with water, a calcium acetate solution and a magnesium acetate solution. Then, the flakes were subjected to thermogravimetric analysis (TGA) using ISO test 11358. The following results were obtained.

[0123]

Table 3

[0124] It was demonstrated that the cellulose ester polymer washed with a salt additive according to the present disclosure retained or increased its molecular weight even after a TGA test at 220 °C for 30 minutes.

[0125] The above sample was also subjected to gel permeation chromatography (GPC) after heating to 220 °C for 30 minutes. The following results were obtained.

[0126]

Table 4

[0127] These and other modifications and variations to the present invention can be made by those skilled in the art without departing from the spirit and scope of the invention as specifically defined by the appended claims. Additionally, it should be understood that aspects of the various embodiments can be interchanged, both in whole or in part. Further, those skilled in the art will understand that the foregoing description is merely an example and is not intended to limit the invention as further described in the appended claims.

Claims

1. A polymer composition comprising: A cellulose ester polymer present in an amount greater than about 40% by weight in the composition and having an acetyl value of about 48% to about 56%; A plasticizer; and A salt additive present in an amount sufficient to reduce the melt flow rate of the polymer composition by about 20% lower than that of an equivalent polymer composition not containing the salt additive. A polymer composition comprising the above.

2. The polymer composition according to Claim 1, wherein the salt additive provides a cationic ion to the polymer composition.

3. The polymer composition according to Claim 1, wherein the salt additive is present in the polymer composition in an amount sufficient to reduce the melt flow rate of the composition by about 30% lower, such as more than about 40%, more than about 50%, more than about 60%, more than about 70%, more than about 80%, etc.

4. The polymer composition according to Claim 1, wherein the melt flow rate of the polymer composition is less than about 20 g / 10 min, such as less than about 18 g / 10 min, less than about 15 g / 10 min, less than about 12 g / 10 min, less than about 10 g / 10 min, less than about 8 g / 10 min, etc., when tested at 210 °C and a load of 2.16 kg.

5. The polymer composition according to any one of Claims 1 to 4, wherein the salt additive results in ionic crosslinking of the cellulose ester polymer.

6. The polymer composition according to any one of Claims 1 to 5, wherein the salt additive is present in the polymer composition in an amount of about 1 ppm to about 10,000 ppm, such as about 10 ppm to about 800 ppm, about 10 ppm to about 1,200 ppm, etc.

7. The polymer composition according to any one of Claims 1 to 6, wherein the salt additive contains a metal salt.

8. The polymer composition according to any one of Claims 1 to 7, wherein the salt additive contains a salt having a polyvalent cation such as a salt having a +2 or +3 cation.

9. The polymer composition according to any one of Claims 1 to 8, wherein the salt additive contains a calcium salt, a magnesium salt, an iron salt, an aluminum salt, a zinc salt, a cobalt salt, a manganese salt, or a mixture thereof.

10. The salt additive includes calcium acetate, magnesium acetate, calcium hydroxide, ferrous acetate, ferric acetate, zinc acetate, cobalt acetate, manganese acetate, magnesium hydroxide, calcium sulfate, calcium bicarbonate, calcium bromide, calcium chloride, calcium nitrate, calcium perchlorate, calcium propionate, calcium benzoate, magnesium bromide, magnesium chlorate, magnesium nitrate, magnesium perchlorate, magnesium sulfate, magnesium thiosulfate, calcium citrate, calcium gluconate, calcium lactate, zinc acetate, cobalt acetate, manganese acetate, lime, or a mixture thereof, and is the polymer composition according to any one of claims 1 to 9.

11. The polymer composition according to any one of claims 1 to 10, wherein the cellulose ester polymer has an acetyl value of more than 50% and less than 54%.

12. The salt additive is present in the composition in an amount sufficient to reduce the L ＊ value of the article formed from the polymer composition, the polymer composition according to any one of claims 1 to 11.

13. The polymer composition according to any one of claims 1 to 12, wherein the cellulose ester polymer is present in the polymer composition in an amount of about 55% by weight to about 95% by weight, and the plasticizer is present in an amount of about 5% by weight to about 40% by weight.

14. The plasticizer includes tris(chloroisopropyl) phosphate, tris(2-chloro-1-methylethyl) phosphate, glycerin, monoacetin, triethyl citrate, acetyltriethyl citrate, phthalate, adipate, polyethylene glycol, triacetin, diacetin, trimethyl phosphate, triethyl phosphate, tributyl phosphate, triphenyl phosphate, tributyl o-acetylcitrate, dibutyl tartrate, ethyl o-benzoylbenzoate, n-ethyltoluenesulfonamide, o-cresyl p-toluenesulfonate, aromatic diol, substituted aromatic diol, aromatic ether, tripropionin, tribenzoin, glycerin ester, glycerol tribenzoate, glycerol acetate benzoate, polyethylene glycol, polyethylene glycol ester, polyethylene glycol diester, di-2-ethylhexyl polyethylene glycol ester, glycerol ester, diethylene glycol, polypropylene glycol, polyglycol diglycidyl ether, dimethyl sulfoxide, N-methylpyrrolidinone, propylene carbonate, C1-C20 dicarboxylic acid ester, di-butyl maleate, di-octyl maleate, resorcinol monoacetate, catechol, catechol ester, phenol, epoxidized soybean oil, castor oil, linseed oil, epoxidized linseed oil, bifunctional glycidyl ether based on polyethylene glycol, alkyl lactone, phospholipid, 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, polycaprolactone diol and mixtures thereof.The polymer composition according to any one of claims 1 to 13.

15. The polymer composition according to any one of claims 1 to 13, wherein the plasticizer includes triacetin, polyethylene glycol, or a mixture thereof.

16. The polymer composition according to any one of claims 1 to 15, wherein the cellulose acetate consists essentially of diacetate cellulose.

17. An article made of the polymer composition according to any one of claims 1 to 16.

18. The article according to claim 17, which is formed by injection molding or extrusion molding.

19. The article according to claim 17, which is a beverage holder, a drinking straw, a pod for hot beverages, a fork, a knife, a spoon, a packaging material, a container, a lid, or an interior part of an automobile.

20. A polymer composition comprising: A cellulose ester polymer that is present in the composition in an amount of more than about 40% by weight and has an acetyl value of about 48% to about 56%; A plasticizer that is present in the polymer composition in an amount of about 12% by weight to about 35% by weight; and A salt additive that imparts a cationic ion to the polymer composition A polymer composition that includes and has a melt flow index of less than 20 g / 10 min when tested at 210 °C and a load of 2.16 kg.

21. The polymer composition according to claim 20, wherein the cellulose ester polymer is present in the polymer composition in an amount of about 60% to about 88% by weight.

22. The polymer composition according to claim 20 or 21, wherein the polymer composition has a melt flow rate of less than about 15 g / 10 min, such as less than about 10 g / 10 min.

23. A polymer composition comprising: A cellulose ester polymer present in the composition in an amount greater than about 40% by weight; A plasticizer; and A salt additive that imparts a cationic ion to the polymer composition and is present in an amount sufficient to reduce the melt flow rate of the polymer composition by about 20% lower than an equivalent polymer composition that does not contain the salt additive. A polymer composition comprising.

24. A polymer composition comprising: A cellulose ester polymer present in the composition in an amount greater than about 40% by weight and having an acetyl value of about 48% to about 56%; A plasticizer A polymer composition that has a melt flow rate of less than about 20 g / 10 min, such as less than about 18 g / 10 min, less than about 15 g / 10 min, less than about 12 g / 10 min, less than about 10 g / 10 min, less than about 8 g / 10 min, when tested at 210 °C and a load of 2.16 kg.

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