Stabilized biodegradable cellulose ester microparticles and processes for stabilizing biodegradable cellulose ester microparticles

Abstract

Biodegradable cellulose ester microparticles can be used in different personal care compositions. However, the biodegradable cellulose ester microparticles can prematurely degrade depending on the type of formulation used. The present application discloses stabilized biodegradable cellulose ester microparticles and processes for the preparation thereof. The stabilized biodegradable cellulose ester microparticles are hydrolytically stable.

Description

[0001] Stabilized Biodegradable Cellulose Ester Microparticles and Processes for Stabilizing Biodegradable Cellulose Ester Microparticles

[0002] BACKGROUND OF THE INVENTION

[0003] Microbeads or microparticles are often used in cosmetics and personal care products due to their ability to deliver multiple application benefits, such as exfoliation, texture enhancement, and oil absorbing properties. Microbeads were historically made of non-biodegradable plastics, such as nylon, polyethylene or polypropylene. When these microbeads are washed off, they can enter water bodies and contribute to plastic pollution. They can be too small to be effectively filtered out by wastewater treatment plants and can be ingested by marine organisms, leading to potential harm to ecosystems. Due to the environmental drawbacks associated with microbeads, many countries and regions have implemented bans or restrictions on their use in cosmetic and personal care products. It is desirable to choose products that minimize the environmental impact. There are various natural and biodegradable alternatives to microbeads available, such as crushed fruit pits, sugar, salt, or environmentally friendly exfoliants like jojoba beads or bamboo particles. Other biodegradable microbeads may be based on modified cellulose such as cellulose esters. Microbeads made from these alternatives provide similar benefits without the environmental concerns.

[0004] Personal care formulations include makeup, lotions, serums, shampoos, conditioners, and cleansers, Water is often a primary ingredient in these personal care products, as it serves as a base and solvent for other ingredients. In general, personal care products can contain anywhere from 50% to 90% water. In the presence of water, the pendant groups of cellulose esters can hydrolyze, forming free organic acids and their salts. Hydrolysis of esters in an aqueous environment is undesirable since it can change the properties of the formulation and may lead to instability of the formulation. This application discloses biodegradable cellulose ester microparticles that have been treated with organic acid salts that are hydrolytically stable in aqueous environment such as in aqueous cosmetic formulations. The application also discloses processes for making the stabilized biodegradable cellulose ester microparticles that are suitable for aqueous environments.

[0005] SUMMARY OF THE INVENTION

[0006] The present application discloses a method, comprising:

[0007] (i) applying an organic acid salt composition comprising an at least one organic acid salt to a cellulose ester particles composition comprising:

[0008] (1 ) cellulose ester particles which comprise a cellulose ester, and

[0009] (2) water, to produce a treated cellulose ester particles composition comprising:

[0010] (1 ) treated cellulose ester particles,

[0011] (2) at least one organic salt, and

[0012] (3) water, wherein the cellulose ester particles and the treated cellulose ester particles have an average particle size of 50-500 microns; and

[0013] (ii) subjecting the treated cellulose ester particles composition to a size reduction process to produce a stabilized cellulose ester microparticles composition comprising:

[0014] (1 ) stabilized cellulose ester microparticles,

[0015] (2) at least one organic acid salt, and

[0016] (3) water, wherein the stabilized cellulose ester microparticles have an average particle size of from 1 -30 microns, and wherein the stabilized cellulose ester microparticles are biodegradable.

[0017] The present application also discloses a composition, comprising: (i) cellulose ester particles, wherein the cellulose ester particles exhibit an average particle size of from 50 to 500 microns, wherein the cellulose ester particles comprise a cellulose ester;

[0018] (ii) 0.1 to 2.0 wt% of an at least one organic acid salt, based on the total the cellulose ester particles; and

[0019] (iii) less than 10wt% of water, based on the total weight of the composition.

[0020] The present application discloses a method, comprising:

[0021] (i) applying an organic acid salt composition comprising an at least one organic acid salt to a cellulose ester microparticles composition, comprising:

[0022] (1 ) cellulose ester microparticles which comprise a cellulose ester, and

[0023] (2) water, to produce a stabilized cellulose ester microparticles composition which comprises:

[0024] (1 ) stabilized cellulose ester microparticles,

[0025] (2) at least one organic acid salt, and

[0026] (3) water, wherein the cellulose ester microparticles have an average particle size of from 1-30 microns, the stabilized cellulose ester microparticles have an average particle size of 1-30 microns, and the stabilized cellulose ester microparticles are biodegradable.

[0027] The present application also discloses a composition, comprising:

[0028] (i) cellulose ester microparticles, wherein the cellulose ester microparticles exhibit an average particle size of from 5 to 30 microns, wherein the cellulose ester microparticles comprise a cellulose ester;

[0029] (ii) 0.1 to 2.0 wt% of an at least one organic acid salt, based on the total weight of the composition; and

[0030] (iii) less than 10wt% of water, based on the total weight of the composition. The present application discloses personal care compositions comprising the stabilized biodegradable cellulose ester microparticles composition.

[0031] DETAILED DESCRIPTION OF THE INVENTION

[0032] Values may be expressed as “about” or “approximately” a given number. Similarly, ranges may be expressed herein as from “about” one particular value and / or to “about” or another particular value. When such a range is expressed, another aspect includes from the one particular value and / or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another aspect.

[0033] As used herein, the terms “a,” “an,” and “the” mean one or more.

[0034] As used herein, the term “and / or,” when used in a list of two or more items, means that any one of the listed items can be employed by itself or any combination of two or more of the listed items can be employed. For example, if a composition is described as containing components A, B, and / or C, the composition can contain A alone; B alone; C alone; A and B in combination; A and C in combination, B and C in combination; or A, B, and C in combination.

[0035] As used herein, the terms “comprising,” “comprises,” and “comprise” are open-ended transition terms used to transition from a subject recited before the term to one or more elements recited after the term, where the element or elements listed after the transition term are not necessarily the only elements that make up the subject.

[0036] As used herein, the terms “having,” “has,” and “have” have the same open-ended meaning as “comprising,” “comprises,” and “comprise” provided above.

[0037] As used herein, the terms “including,” “includes,” and “include” have the same open-ended meaning as “comprising,” “comprises,” and “comprise” provided above. “Degree of Substitution” or “average degree of substitution” is used to describe the average substitution level of the substituents per anhydroglucose unit (“AGU”). Generally, conventional cellulose contains three hydroxyl groups in each AGU that can be substituted. Therefore, the DS can have a value between 0 and 3. However, low molecular weight cellulose mixed esters can have a total degree of substitution slightly above 3 from end group contributions. Low molecular weight cellulose mixed esters are discussed in more detail subsequently in this disclosure. Because DS is a statistical mean value, a value of 1 does not assure that every AGU has a single substituent. In some cases, there can be unsubstituted anhydroglucose units, some with two and some with three substituents, and more often than not the value will be a noninteger. Total DS is defined as the average number of all of substituents per anhydroglucose unit. The degree of substitution per AGU can also refer to a particular substituent, such as, for example, hydroxyl, acetyl, butyryl, or propionyl. Additionally, the degree of substitution can specify a given hydroxyl content based on the carbon unit of the anhydroglucose unit.

[0038] When the degree of substitution refers to hydroxyl, i.e, DSOH, the reference is to the average hydroxyl groups per anhydroglucose that are not substituted. As a result, DSOH is not used in the calculation of the total degree of substitution.

[0039] Numerical Ranges

[0040] The present description uses numerical ranges to quantify certain parameters relating to the invention. It should be understood that when numerical ranges are provided, such ranges are to be construed as providing literal support for claim limitations that only recite the lower value of the range as well as claim limitations that only recite the upper value of the range. For example, a disclosed numerical range of 10 to 100 provides literal support for a claim reciting “greater than 10” (with no upper bounds) and a claim reciting “less than 100” (with no lower bounds).

[0041] The present description uses specific numerical values to quantify certain parameters relating to the invention, where the specific numerical values are not expressly part of a numerical range. It should be understood that each specific numerical value provided herein is to be construed as providing literal support for a broad, intermediate, and narrow range. The broad range associated with each specific numerical value is the numerical value plus and minus 60 percent of the numerical value, rounded to two significant digits. The intermediate range associated with each specific numerical value is the numerical value plus and minus 30 percent of the numerical value, rounded to two significant digits. The narrow range associated with each specific numerical value is the numerical value plus and minus 15 percent of the numerical value, rounded to two significant digits. For example, if the specification describes a specific temperature of 62 °F, such a description provides literal support for a broad numerical range of 25 °F to 99 °F (62 °F + / - 37 °F), an intermediate numerical range of 43 °F to 81 °F (62 °F + / - 19 °F), and a narrow numerical range of 53 °F to 71 °F (62 °F + / - 9 °F). These broad, intermediate, and narrow numerical ranges should be applied not only to the specific values, but should also be applied to differences between these specific values. Thus, if the specification describes a first pressure of 110 psia and a second pressure of 48 psia (a difference of 62 psi), the broad, intermediate, and narrow ranges for the pressure difference between these two streams would be 25 to 99 psi, 43 to 81 psi, and 53 to 71 psi, respectively.

[0042] Throughout this application, where patents or publications are referenced, the disclosures of these references in their entireties are intended to be incorporated by reference into this application, to the extent they are not inconsistent with the present invention, in order to more fully describe the state of the art to which the invention pertains. Cellulose Esters

[0043] Generally, the cellulose esters can be produced by any method known in the art. Examples of processes for producing cellulose esters are taught in Kirk- Othmer, Encyclopedia of Chemical Technology, 5th Edition, Vol. 5, Wiley- Interscience, New York (2004), pp. 394-444, the disclosure of which is incorporated by reference in its entirety. Cellulose, the starting material for producing cellulose esters, can be obtained in different grades and from sources such as, for example, cotton linters, softwood pulp, hardwood pulp, corn fiber and other agricultural sources, and bacterial celluloses.

[0044] One method of producing cellulose esters is by esterification. In such a method, the cellulose is mixed with the appropriate organic acids, acid anhydrides, and catalysts and then converted to a cellulose triester. Ester hydrolysis is then performed by adding a water-acid mixture to the cellulose triester, which can be filtered to remove any gel particles or fibers. Water is added to the mixture to precipitate out the cellulose ester. The cellulose ester can then be washed with water to remove reaction by-products followed by dewatering and drying.

[0045] Acylating reagents suitable for use herein can include, but are not limited to, alkyl or aryl carboxylic anhydrides, carboxylic acid halides, and / or carboxylic acid esters containing the above-described alkyl or aryl groups suitable for use in the acyl substituents of the substituted cellulose esters described herein. Examples of suitable carboxylic anhydrides include, but are not limited to, acetic anhydride, propionic anhydride, butyric anhydride, pivaloyl anhydride, benzoic anhydride, and naphthoyl anhydride. Examples of carboxylic acid halides include, but are not limited to, acetyl, propionyl, butyryl, pivaloyl, benzoyl, and naphthoyl chlorides or bromides. Examples of carboxylic acid esters include, but are not limited to, acetyl, propionyl, butyryl, pivaloyl, benzoyl and naphthoyl methyl esters. In one or more embodiments, the acylating reagent can be one or more carboxylic anhydrides selected from the group consisting of acetic anhydride, propionic anhydride, butyric anhydride, pivaloyl anhydride, benzoyl anhydride, and naphthoyl anhydride.

[0046] In various embodiments, the cellulose triesters that are hydrolyzed can have three substituents selected independently from alkanoyls having from 2 to 12 carbon atoms. Examples of cellulose triesters include cellulose triacetate, cellulose tripropionate, cellulose tributyrate, or mixed triesters of cellulose, such as cellulose acetate propionate and cellulose acetate butyrate. These cellulose triesters can be prepared by a number of methods known to those skilled in the art. For example, cellulose triesters can be prepared by heterogeneous acylation of cellulose in a mixture of carboxylic acid and anhydride in the presence of a catalyst, such as H2SO4. Cellulose triesters can also be prepared by the homogeneous acylation of cellulose dissolved in an appropriate solvent such as LiCI / DMAc or LiCI / NMP.

[0047] After esterification of the cellulose to the triester, part of the acyl substituents can be removed by hydrolysis or by alcoholysis to give a secondary cellulose ester. Secondary cellulose esters can also be prepared directly with no hydrolysis by using a limiting amount of acylating reagent. This process is particularly useful when the reaction is conducted in a solvent that will dissolve cellulose.

[0048] The cellulose esters thus prepared generally comprise the following structure: where R2, R3, and R6are hydrogen (with the proviso that R2, R3, and R6are not hydrogen simultaneously), alkyl-acyl groups, and / or aryl-acyl groups (such as those described above) bound to the cellulose via an ester linkage. The degree of polymerization (“DP”) of the cellulose esters prepared by these methods can be at least 10. In other embodiments, the DP of the cellulose esters can be at least 50, at least 100, or at least 250. In other embodiments, the DP of the cellulose esters can be in the range of from about 5 to about 100, or in the range of from about 10 to about 50. As used herein, the term “degree of polymerization,” when referring to cellulose esters, shall denote the average number of anhydroglucose monomer units per cellulose polymer chain.

[0049] In one embodiment or in combination with any other embodiment, the cellulose esters can have a DP of at least 110, at least 120, at least 130, at least 140, at least 150, at least 160, at least 170, at least 180, at least 190, at least 200, at least 210, at least 220, at least 230, at least 240 and / or up to 350, up to 325, or up to 300.

[0050] The present application discloses a method in a first aspect, comprising: (i) applying an organic acid salt composition comprising an at least one organic acid salt to a cellulose ester particles composition comprising: (1 ) cellulose ester particles which comprise a cellulose ester, and (2) water, to produce a treated cellulose ester particles composition comprising: (1) treated cellulose ester particles, (2) at least one organic salt, and (2) water, wherein the cellulose ester particles and the treated cellulose ester particles have an average particle size of 50-500 microns; and (ii) subjecting the treated cellulose ester particles composition to a size reduction process to produce a stabilized cellulose ester microparticles composition comprising: (1) stabilized cellulose ester microparticles, (2) at least one organic acid salt, and (3) water, wherein the stabilized cellulose ester microparticles have an average particle size of from 1 - 30 microns, and wherein the stabilized cellulose ester microparticles are biodegradable.

[0051] The compositions comprising the cellulose ester particles and the treated cellulose ester particles can be a free-flowing particulate material, a suspension, a slurry, a mixture, a dispersion or a phase separated composition depending on the water content. The free-flowing particulate material also has a water content.

[0052] In one embodiment or in combination with any other embodiment of this first aspect, the water is present in the cellulose ester particles composition at from 1 -99wt%, or 1 -10wt%, or 2-10wt%, or 3-10wt%, or 4-10w%, or 1-9wt%, or 1 -8wt%, or 1 -7wt%, or 1 -6wt%, or 1 -5wt%, or 1 -4wt%, or 1 -3wt%, or 1 -2wt%, or

[0053] 2-9wt%, or 2-8wt%, or 2-7wt%, or 2-6wt%, or 3-9wt%, or 3-8wt%, or 3-7wt%, or

[0054] 3-6wt%, or 4-10wt%, or 4-9wt%, or 4-8wt%, or 4-7wt%, or 4-6wt%, or 4-5wt%, or 5-10wt%, or 5-9wt%, or 5-8wt%, or 5-7wt%, or 5-6wt%, or 6-10wt%, or 6-9wt%, or 6-8wt%, or 10-30wt%, or 10-25wt%, or 10-20wt%, or 10-15wt%, or 15-30wt%, or 15-25wt%, or 15-20wt%, or 30-99wt%, or 30-90wt%, or 30-80wt%, or 30- 70wt%, or 30-60wt%, or 30-50wt%, or 40-99wt%, or 40-90wt%, or 40-80wt%, or 40-70wt%, or 40-60wt%, or 50-99wt%, or 50-90wt%, or 50-80wt%, or 50-70wt%, or 60-99wt%, or 60-90wt%, or 60-80wt%, or 70-99wt%, 70-90wt%, or 80-99wt%, or 90-99wt% based on the total weight of the cellulose ester particles composition.

[0055] In one embodiment or in combination with any other embodiment of this first aspect, the water is present in the treated cellulose ester particles composition at from 1 -99wt%, or 1-10wt%, or 1 -9wt%, or 1 -8wt%, or 1 -7wt%, or 1 -6wt%, or 2-10wt%, or 2-9wt%, or 2-8wt%, or 2-7wt%, or 2-6wt%, or 3-10wt%, or 3-9wt%, or 3-8wt%, or 3-7wt%, or 3-6wt%, or 4-10w%, or 4-9wt%, or 4-8wt%, or 4-7wt%, or 4-6wt%, or 4-5wt%, or 1-9wt%, or 1 -8wt%, or 1 -7wt%, or 1-6wt%, %, or 1 -5wt%, or 1 -4wt%, or 1 -3wt%, or 1-2wt%, or 2-9wt%, or 2-8wt%, or 2- 7wt%, or 2-6wt%, or 2-5wt%, or 3-9wt%, or 3-8wt%, or 3-7wt%, or 3-6wt%, or 4- 10wt%, or 4-9wt%, or 4-8wt%, or 4-7wt%, or 4-6wt%, or 4-5wt%, or 5-10wt%, or 5-9wt%, or 5-8wt%, or 5-7wt%, or 5-6wt%, or 6-10wt%, or 6-9wt%, or 6-8wt%, or 10-30wt%, or 10-25wt%, or 10-20wt%, or 10-15wt%, or 15-30wt%, or 15-25wt%, or 15-20wt%, or 30-99wt%, or 30-90wt%, or 30-80wt%, or 30-70wt%, or 30-

[0056] 60wt%, or 30-50wt%, or 40-99wt%, or 40-90wt%, or 40-80wt%, or 40-70wt%, or 40-60wt%, or 50-99wt%, or 50-90wt%, or 50-80wt%, or 50-70wt%, or 60-99wt%, or 60-90wt%, or 60-80wt%, or 70-99wt%, 70-90wt%, or 80-99wt%, or 90-99wt% based on the total weight of the treated cellulose ester particles composition. The water present in the treated cellulose ester particles composition can be adjusted by adding water to the composition or by drying the composition by any method known to one of ordinary skill in the art. Nonlimiting examples include by distillation at atmospheric pressure or at a pressure that is lower than atmospheric pressure; by simply applying vacuum; air drying, or by freeze drying the treated cellulose ester particles composition.

[0057] In one embodiment or in combination with any other embodiment of this first aspect, the water is present in the stabilized cellulose ester microparticles composition at from 1 -10wt%, or 2-10wt%, or 3-10wt%, or 4-10w%, or 1 -9wt%, or 1 -8wt%, or 1 -7wt%, or 1 -6wt%, or 1 -5wt%, or 1 -4wt%, or 1 -3wt%, or 2-9wt%, or

[0058] 2-8wt%, or 2-7wt%, or 2-6wt%, or 2-5wt%, or 2-4wt%, or 3-9wt%, or 3-8wt%, or

[0059] 3-7wt%, or 3-6wt%, or 3-5wt%, based on the total weight of the stabilized cellulose ester microparticles composition. The water present in the stabilized cellulose ester microparticles composition can be adjusted by adding water to the composition or by drying the composition by any method known to one of ordinary skill in the art. Nonlimiting examples include by distillation at atmospheric pressure or at a pressure that is lower than atmospheric pressure; by simply applying vacuum; air drying, or by freeze drying the stabilized cellulose ester microparticles composition.

[0060] In one embodiment or in combination with any other embodiment of this first aspect, the at least one organic acid salt in step (i) is present at from 0.1 - 2wt%, or 0.1 -1 .5wt%, or 0.1 -1.0wt%, or 0.1 -0.5wt%, or 0.2-1 ,5wt%, or 0.2- 1 .0wt%, or 0.2-0.5wt%, or 0.3-2wt%, or 0.3-1 .5wt%, or 0.3-1 .0wt%, or 0.3- 0.5wt%, or 0.4-2wt%, or 0.4-1 ,5wt%, or 0.4-1 .0wt%, or 0.4-0.5wt%, 1 -2wt%, 1 - 1 .5wt%, based on the total weight of the composition treated cellulose ester particles composition. In one embodiment or in combination with any other embodiment of this first aspect, the at least one organic acid salt in step (ii) is present at from 0.1 - 2wt%, or 0.1 -1 .5wt%, or 0.1 -1.0wt%, or 0.1 -0.5wt%, or 0.2-1 ,5wt%, or 0.2- 1 .0wt%, or 0.2-0.5wt%, or 0.3-2wt%, or 0.3-1 .5wt%, or 0.3-1 .0wt%, or 0.3- 0.5wt%, or 0.4-2wt%, or 0.4-1 ,5wt%, or 0.4-1 .0wt%, or 0.4-0.5wt%, 1 -2wt%, 1 - 1 .5wt%, based on the total weight of the stabilized cellulose ester particles composition.

[0061] In one embodiment or in combination with any other embodiment of this first aspect, the at least one organic acid salt comprises an alkali metal cation or an alkaline metal cation.

[0062] In one class of this embodiment, the alkali metal cation is Li+, Na+, or K+, and the alkaline metal cation is Mg2+or Ca2+.

[0063] In one class of this embodiment, the organic acid component of the at least one organic acid salt is derived from a compound of formula I: , wherein: G is a (Ci-8)alkylene, wherein the alkylene is unsubstituted or substituted by 1 to 2 hydroxyl substituents, a (Ci-8)alkenyl, or a phenyl; and n is 0, 1 , or 2. In one class of this embodiment or in combination with any other class, the compound of formula I is glutaric acid, pimelic acid, azelaic acid, sebacic acid, suberic acid, adipic acid, succinic acid, citric acid, tartaric acid, fumaric acid, terephthalic acid, isophthalic acid, acetic acid, or propionic acid, or lactic acid. In one subclass of this class, the alkali metal cation is Li+, Na+, or K+, and the alkaline metal cation is Mg2+or Ca2+.

[0064] In one embodiment or in combination with any other embodiment of this first aspect, the organic acid salt is sodium succinate, potassium succinate, magnesium succinate, calcium succinate, sodium citrate, potassium citrate, magnesium citrate, calcium citrate, sodium acetate, potassium acetate, magnesium acetate, calcium acetate, sodium lactate, potassium lactate, magnesium lactate, calcium lactate, or a combination thereof.

[0065] In one embodiment or in combination with any other embodiment of this first aspect, the organic acid salt composition is a solid, an aqueous suspension or an aqueous solution. In one class of this embodiment, the organic acid salt composition is an aqueous suspension. In one class of this embodiment, the organic acid salt composition is an aqueous solution. In one class of this embodiment, the organic acid salt composition is an aqueous solid. In one class of this embodiment, the organic acid salt composition is an aqueous suspension or an aqueous solution.

[0066] In one embodiment or in combination with any other embodiment of this first aspect, the organic acid salt composition is the aqueous solution, and the applying is conducted by spraying the organic acid salt composition onto the cellulose ester particles or mixing the organic acid salt composition with the cellulose ester particles; or the applying is conducted by spraying the organic acid salt composition onto the cellulose ester particles composition. In one class of this embodiment, the applying is conducted by spraying the organic acid salt composition onto the cellulose ester particles. In one class of this embodiment, the applying is conducted by mixing the composition with the cellulose ester particles. In one class of this embodiment, the applying is conducted by spraying the organic acid salt composition onto the cellulose ester particles composition.

[0067] In one embodiment or in combination with any other embodiment of this first aspect, the organic acid salt composition is an aqueous suspension, and the applying is done by mixing the organic acid salt composition with the cellulose ester particles. In one embodiment or in combination with any other embodiment of this first aspect, the organic acid salt composition is a solid, and the applying is done by mixing the organic acid salt composition with the cellulose ester particles or the cellulose ester particles composition. In one embodiment or in combination with any other embodiment of this first aspect, the organic acid salt composition is a solid, and the applying is done by mixing the organic acid salt composition with the cellulose ester particles. In one embodiment or in combination with any other embodiment of this first aspect, the organic acid salt composition is a solid, and the applying is done by mixing the organic acid salt composition with the cellulose ester particles composition. The solid can be a particulate solid.

[0068] In one embodiment or in combination with any other embodiment of this first aspect, the size reduction process is a mechanical grinding process, or a milling process. In one class of this embodiment, the size reduction process is a mechanical grinding process. In one class of this embodiment, the size reduction process is a milling process. In one subclass of this class, the milling process is jet milling.

[0069] In one embodiment or in combination with any other embodiment of this first aspect, wherein the cellulose ester is a cellulose acetate, a cellulose propionate, a cellulose butyrate, a cellulose acetate propionate, a cellulose acetate butyrate, or a combination thereof.

[0070] In one class of this embodiment, the cellulose ester is a cellulose acetate. In one class of this embodiment, the cellulose ester is a cellulose acetate propionate, a cellulose acetate butyrate, a cellulose propionate, or a cellulose butyrate. In one class of this embodiment, the cellulose ester is a cellulose acetate propionate, or a cellulose acetate butyrate. In one class of this embodiment, the cellulose ester is a cellulose acetate propionate. In one class of this embodiment, the cellulose ester is a cellulose acetate butyrate. In one class of this embodiment, the cellulose ester is a cellulose propionate. In one class of this embodiment, the cellulose ester is a cellulose butyrate.

[0071] In one embodiment or in combination with any other embodiment of this first aspect, the cellulose ester has an average degree of substitution for hydroxyl substituents (“DSOH”) that is at least 0.5, or at least 0.6, or at least 0.7, or at least 0.8, or at least 0.9, or in the range of 0.5 to 1 .0, or in the range of 0.6 to 1 .0, or in the range of 0.7 to 1 .0, or in the range of 0.8 to 1 .0, or in the range of 0.9 to 1 .0. In one embodiment or in combination with any other embodiment of this first aspect, the cellulose ester has an average degree of substitution for hydroxyl substituents (“DSOH”) that is in the range of 0.5 to 1 .0, or in the range of 0.6 to 1 .0, or in the range of 0.7 to 1 .0, or in the range of 0.8 to 1 .0, or in the range of 0.9 to 1.0.

[0072] In one embodiment or in combination with any other embodiment of this first aspect, the cellulose ester has a weight average molecular weight in the range of from 5,000 to 100,000 Da, or 5,000 to 50,000 Da, or 5,000 to 25,000 Da, or 15,000 to 100,000 Da, or 15,000 to 50,000 Da, or 15,000 to 25,000 Da, or 50,000 to 100,000 Da, or 75,000 to 100,000 Da, or 15,000 to 250,000 Da.

[0073] In one embodiment or in combination with any other embodiment of this first aspect, the stabilized cellulose ester microparticles have: (i) a sphericity in the range of 30 to 100 percent, and (ii) a bulk density in the range of 0.2 to 0.7. In one class of this embodiment, the sphericity is in the range of from 30 to 90 percent, in the range of from or in the range of from 30 to 80 percent, or in the range of from 30 to 70 percent, or in the range of from 30 to 60 percent, or in the range of from 30 to 50 percent, or in the range of from 40 to 100 percent, or in the range of from 40 to 90 percent, or in the range of from 40 to 80 percent, or in the range of from 40 to 70 percent, or in the range of from 40 to 60 percent, or in the range of from 40 to 50 percent, or in the range of from 50 to 100 percent, or in the range of from 60 to 100 percent, or in the range of from 70 to 100 percent, or in the range of from 80 to 100 percent, or in the range of from 90 to 100 percent.

[0074] In one embodiment or in combination with any other embodiment of this first aspect, the cellulose ester particles and the stabilized cellulose ester microparticles further comprise a plasticizer. The plasticizer reduces the melt temperature, the Tg, and / or the melt viscosity of the cellulose ester.

[0075] In one class of this embodiment or in combination with any other embodiment, class or subclass of the first aspect, the plasticizer is triacetin, triethyl citrate, polyethylene glycol), Benzoflex, propylene glycol, polysorbatemsucrose octaacetate, acetylated triethyl citrate, acetyl tributyl citrate, Admex, tripropionin, Scandiflex, poloxamer copolymers, polyethylene glycol succinate, diisobutyl adipate, polyvinyl pyrollidone, and glycol tribenzoate.

[0076] In one class of this embodiment or in combination with any other embodiment, class or subclass of this first aspect, the plasticizer is present in an amount of from 1 to 40 wt%, or 1 to 30 wt%, or 1 to 20 wt%, or 1 to 10 wt%, or 1 to 5 wt%, or 5 to 40 wt%, or 5 to 30 wt%, or 5 to 20 wt%, or 5 to 10 wt%, or 5 to 5 wt%, or 10 to 40 wt%, or 10 to 30 wt%, or 10 to 20 wt%, or 10 to 10 wt%, or 10 to 5 wt%, 15 to 40 wt%, or 15 to 30 wt%, or 15 to 20 wt%, or 15 to 10 wt%, or 15 to 5 wt%, based on the weight of the cellulose ester microparticles.

[0077] In one class of this embodiment, the plasticizer is a biodegradable plasticizer. Some examples of biodegradable plasticizers include triacetin, triethyl citrate, acetyl triethyl citrate, polyethylene glycol, the benzoate-containing plasticizers such as the Benzoflex™ plasticizer series, poly (alkyl succinates) such as poly (butylene succinate), polyethersulfones, adipate-based plasticizers, soybean oil epoxides such as the Paraplex™ plasticizer series, sucrose-based plasticizers, dibutyl sebacate, tributyrin, sucrose acetate isobutyrate, the Resolflex™ series of plasticizers, triphenyl phosphate, glycolates, polyethylene glycol), 2,2,4-trimethylpentane-1 ,3-diyl bis(2-methylpropanoate), and polycaprolactones.

[0078] In one embodiment or in combination with any other embodiment, class or subclass of this first aspect, the cellulose ester particles in the cellulose ester particles composition further comprise at least one biodegradable polymer that is different than the cellulose ester.

[0079] In one class of this embodiment or in combination with any other embodiment, class, or subclass of this first aspect, the at least one biodegradable polymer is chosen from polyhydroxyalkanoates (PHAs and PHBs), poly(lactic acid) (PLA), polycaprolactone polymers (PCL), poly(butylene adipate co-terephthalate) (PBAT), polyethylene succinate) (PES), poly(vinyl acetates) (PVAs), poly(butylene succinate) (PBS) and copolymers [such as poly(butylene succinate-co-adipate) (PBSA)], other cellulose esters, cellulose ethers, starch, proteins, derivatives thereof, and combinations thereof.

[0080] In one embodiment or in combination with any other embodiment, class or subclass of this first aspect, the method further comprises a step (iii) filtering the treated cellulose ester compositions; after the applying step (i) but before the subjecting step (ii). The filtering is done to remove excess water if there is excess water. The filtering could also be used to perform a size exclusion of the treated cellulose ester particles composition.

[0081] In one class or in combination with any other embodiment, class or subclass of this first aspect, the method further comprises a step (iv) drying the treated cellulose ester composition; after the filtering step (iii), but before the subjecting step (ii). In one subclass or in combination with any other embodiment, class or subclass of this first aspect, the method further comprises a step (v) drying the stabilized cellulose ester composition; after the subjecting step (ii).

[0082] In one embodiment or in combination with any other embodiment, class or subclass of this first aspect, the method further comprises a step (vi) drying the stabilized cellulose ester composition; after the subjecting step (ii).

[0083] The drying in steps can be performed by blowing air over the stabilized cellulose ester microparticles composition, wherein the air is heated at or below a temperature of 100°C, or 90°C, or 80°C, or 70°C, or 60°C, or 50°C, or 50°C.

[0084] The present application also discloses a composition of a second aspect, comprising: (i) cellulose ester particles, wherein the cellulose ester particles exhibit an average particle size of from 50 to 500 microns, wherein the cellulose ester particles comprise a cellulose ester; (ii) 0.1 to 2.0 wt% of an at least one organic acid salt, based on the total the cellulose ester particles; and (iii) less than 10wt% of water, based on the total weight of the composition. In one embodiment or in combination with any other embodiment of this second aspect, the at least one organic acid salt is present at from 0.1 -2.0wt%, or 0.1-1 .5wt%, or 0.1 -1.0wt%, or 0.1 -0.5wt%, or 0.2-1 ,5wt%, or 0.2-1 .0wt%, or 0.2-0.5wt%, or 0.3-2wt%, or 0.3-1 .5wt%, or 0.3-1 .0wt%, or 0.3-0.5wt%, or 0.4- 2wt%, or 0.4-1 ,5wt%, or 0.4-1 .0wt%, or 0.4-0.5wt%, 1 -2wt%, 1 -1.5wt%, based on the total weight of the composition.

[0085] In one embodiment or in combination with any other embodiment of the second aspect, the water is present in the composition at less than 9.9wt%, or less than 9wt%, or less than 8 wt%, or less than 7wt%, or less than 6wt%, or less than 5wt%, or less than 4wt%, or less than 3wt%, or less than 2wt%, or less than 1wt%, or in the range of from 1-9.9wt%, or in the range of from 2-9.9wt%, or in the range of from 3-9.9%, or in the range of form 4-9.9wt%, or in the range of from 5-9.9wt%, or in the range of from 1-9wt%, or in the range of from 2-9.9wt%, or in the range of from 2-9wt%, or in the range of from 3-9wt%, or in the range of form 4-9wt%, or in the range of from 5-9wt%, or in the range of from 6-9wt%, or in the range of from 7-9wt%, or in the range of from 1-8wt%, or in the range of from 2-8wt%, or in the range of from 3-8wt%, or in the range of form 4-8wt%, or in the range of from 5-8wt%, or in the range of from 6-8wt%, or in the range of from 1 -7wt%, or in the range of from 2-7wt%, or in the range of from 3-7wt%, or in the range of form 4-7wt%, or in the range of from 5-7wt%, or in the range of from 1 -6wt%, or in the range of from 2-6wt%, or in the range of from 3-6wt%, or in the range of form 4-6wt%, or in the range of from 5-6wt%, or in the range of from 1 -5wt%, or in the range of from 2-5wt%, or in the range of from 3-5wt%, or in the range of form 4-5wt%, based on the total weight of the composition.

[0086] In one embodiment or in combination with any other embodiment of the second aspect, the at least one organic acid salt comprises an alkali metal cation or an alkaline metal cation.

[0087] In one class of this embodiment, the alkali metal cation is Li+, Na+, or K+, and the alkaline metal cation is Mg2+or Ca2+. In one class of this embodiment, the organic acid component of the at least one organic acid salt is derived from a compound of formula I: , wherein: G is a (Ci-8)alkylene, wherein the alkylene is unsubstituted or substituted by 1 to 2 hydroxyl substituents, a (Ci-8)alkenyl, or a phenyl; and n is 0, 1 , or 2. In one class of this embodiment, the compound of formula I is glutaric acid, pimelic acid, azelaic acid, sebacic acid, suberic acid, adipic acid, succinic acid, citric acid, tartaric acid, fumaric acid, terephthalic acid, isophthalic acid, acetic acid, or propionic acid, or lactic acid. In one subclass of this class, the alkali metal cation is Li+, Na+, or K+, and the alkaline metal cation is Mg2+or Ca2+.

[0088] In one embodiment or in combination with any other embodiment of the second aspect, the organic acid salt is sodium succinate, potassium succinate, magnesium succinate, calcium succinate, sodium citrate, potassium citrate, magnesium citrate, calcium citrate, sodium acetate, potassium acetate, magnesium acetate, calcium acetate, sodium lactate, potassium lactate, magnesium lactate, calcium lactate, or a combination thereof.

[0089] In one embodiment or in combination with any other embodiment of the second aspect, wherein the cellulose ester is a cellulose acetate, a cellulose propionate, a cellulose butyrate, a cellulose acetate propionate, a cellulose acetate butyrate, or a combination thereof.

[0090] In one class of this embodiment, the cellulose ester is a cellulose acetate. In one class of this embodiment, the cellulose ester is a cellulose acetate propionate, a cellulose acetate butyrate, a cellulose propionate, or a cellulose butyrate. In one class of this embodiment, the cellulose ester is a cellulose acetate propionate, or a cellulose acetate butyrate. In one class of this embodiment, the cellulose ester is a cellulose acetate propionate. In one class of this embodiment, the cellulose ester is a cellulose acetate butyrate. In one class of this embodiment, the cellulose ester is a cellulose propionate. In one class of this embodiment, the cellulose ester is a cellulose butyrate.

[0091] In one embodiment or in combination with any other embodiment of the second aspect, the cellulose ester has an average degree of substitution for hydroxyl substituents (“DSOH”) that is at least 0.5, or at least 0.6, or at least 0.7, or at least 0.8, or at least 0.9, or in the range of 0.5 to 1 .0, or in the range of 0.6 to 1 .0, or in the range of 0.7 to 1 .0, or in the range of 0.8 to 1 .0, or in the range of 0.9 to 1.0.

[0092] In one embodiment or in combination with any other embodiment of the second aspect, the cellulose ester has an average degree of substitution for hydroxyl substituents (“DSOH”) that is in the range of 0.5 to 1 .0, or in the range of 0.6 to 1 .0, or in the range of 0.7 to 1 .0, or in the range of 0.8 to 1 .0, or in the range of 0.9 to 1 .0.

[0093] In one embodiment or in combination with any other embodiment of the second aspect, the cellulose ester has a weight average molecular weight in the range of from 5,000 to 100,000 Da, or 5,000 to 50,000 Da, or 5,000 to 25,000 Da, or 15,000 to 100,000 Da, or 15,000 to 50,000 Da, or 15,000 to 25,000 Da, or 50,000 to 100,000 Da, or 75,000 to 100,000 Da, or 15,000 to 250,000 Da.

[0094] In one embodiment or in combination with any other embodiment of the second aspect, wherein cellulose ester particles have: (i) a sphericity in the range of 30 to 100 percent, and (ii) a bulk density in the range of 0.2 to 0.7. In one class of this embodiment, the sphericity is in the range of from 30 to 90 percent, in the range of from or in the range of from 30 to 80 percent, or in the range of from 30 to 70 percent, or in the range of from 30 to 60 percent, or in the range of from 30 to 50 percent, or in the range of from 40 to 100 percent, or in the range of from 40 to 90 percent, or in the range of from 40 to 80 percent, or in the range of from 40 to 70 percent, or in the range of from 40 to 60 percent, or in the range of from 40 to 50 percent, or in the range of from 50 to 100 percent, or in the range of from 60 to 100 percent, or in the range of from 70 to 100 percent, or in the range of from 80 to 100 percent, or in the range of from 90 to 100 percent.

[0095] In one embodiment or in combination with any other embodiment of the second aspect, the cellulose ester particles further comprise a plasticizer. The plasticizer reduces the melt temperature, the Tg, and / or the melt viscosity of the cellulose ester.

[0096] In one class of this embodiment or in combination with any other embodiment, class or subclass of the second aspect, the plasticizer is triacetin, triethyl citrate, polyethylene glycol), Benzoflex, propylene glycol, polysorbatemsucrose octaacetate, acetylated triethyl citrate, acetyl tributyl citrate, Admex, tripropionin, Scandiflex, poloxamer copolymers, polyethylene glycol succinate, diisobutyl adipate, polyvinyl pyrollidone, and glycol tribenzoate.

[0097] In one class of this embodiment or in combination with any other embodiment, class or subclass of this second aspect, the plasticizer is present in an amount of from 1 to 40 wt%, or 1 to 30 wt%, or 1 to 20 wt%, or 1 to 10 wt%, or 1 to 5 wt%, or 5 to 40 wt%, or 5 to 30 wt%, or 5 to 20 wt%, or 5 to 10 wt%, or 5 to 5 wt%, or 10 to 40 wt%, or 10 to 30 wt%, or 10 to 20 wt%, or 10 to 10 wt%, or 10 to 5 wt%, 15 to 40 wt%, or 15 to 30 wt%, or 15 to 20 wt%, or 15 to 10 wt%, or 15 to 5 wt%, based on the weight of the cellulose ester microparticles.

[0098] In one class of this embodiment, the plasticizer is a biodegradable plasticizer. Some examples of biodegradable plasticizers include triacetin, triethyl citrate, acetyl triethyl citrate, polyethylene glycol, the benzoate-containing plasticizers such as the Benzoflex™ plasticizer series, poly (alkyl succinates) such as poly (butylene succinate), polyethersulfones, adipate-based plasticizers, soybean oil epoxides such as the Paraplex™ plasticizer series, sucrose-based plasticizers, dibutyl sebacate, tributyrin, sucrose acetate isobutyrate, the Resolflex™ series of plasticizers, triphenyl phosphate, glycolates, polyethylene glycol), 2,2,4-trimethylpentane-1 ,3-diyl bis(2-methylpropanoate), and polycaprolactones. In one embodiment or in combination with any other embodiment, class or subclass of this second aspect, the composition further comprises at least one biodegradable polymer that is different than the cellulose ester.

[0099] In one class of this embodiment or in combination with any other embodiment of this second aspect, class or subclass, the biodegradable polymer is chosen from polyhydroxyalkanoates (PHAs and PHBs), poly(lactic acid) (PLA), polycaprolactone polymers (PCL), poly(butylene adipate co-terephthalate) (PBAT), polyethylene succinate) (PES), poly(vinyl acetates) (PVAs), poly(butylene succinate) (PBS) and copolymers [such as poly(butylene succinate-co-adipate) (PBSA)], other cellulose esters, cellulose ethers, starch, proteins, derivatives thereof, and combinations thereof.

[0100] The present application discloses a method in a third aspect, comprising: (i) applying an organic acid salt composition comprising an at least one organic acid salt to a cellulose ester microparticles composition, comprising: (1) cellulose ester microparticles which comprise a cellulose ester, and (2) water, to produce a stabilized cellulose ester microparticles composition which comprises: (1 ) stabilized cellulose ester microparticles, (2) at least one organic acid salt, and (3) water, wherein the cellulose ester microparticles have an average particle size of from 1 -30 microns, the stabilized cellulose ester microparticles have an average particle size of 1 -30 microns, and the stabilized cellulose ester microparticles are biodegradable.

[0101] The compositions comprising the cellulose ester microparticles and the stabilized cellulose ester microparticles can be a free-flowing particulate material, a slurry, a mixture, a dispersion or a phase separated composition depending on the water content. The free-flowing particulate material also has a water content.

[0102] In one embodiment or in combination with any other embodiment of this third aspect, the water is present in the cellulose ester microparticles composition at from 1 -99wt%, or 1 -10wt%, or 1 -9wt%, or 1-8wt%, or 1-7wt%, or 1-6wt%, or 2- 10wt%, or 2-9wt%, or 2-8wt%, or 2-7wt%, or 2-6wt%, or 3-10wt%, or 3-9wt%, or 3-8wt%, or 3-7wt%, or 3-6wt%, or 4-10w%, or 4-9wt%, or 4-8wt%, or 4-7wt%, or

[0103] 4-6wt%, or 4-5wt%, or 1 -9wt%, or 1 -8wt%, or 1 -7wt%, or 1 -6wt%, %, or 1 -5wt%, or 1 -4wt%, or 1 -3wt%, or 1-2wt%, or 2-9wt%, or 2-8wt%, or 2-7wt%, or 2-6wt%, or 2-5wt%, or 3-9wt%, or 3-8wt%, or 3-7wt%, or 3-6wt%, or 4-10wt%, or 4-9wt%, or 4-8wt%, or 4-7wt%, or 4-6wt%, or 4-5wt%, or 5-10wt%, or 5-9wt%, or 5-8wt%, or 5-7wt%, or 5-6wt%, or 6-10wt%, or 6-9wt%, or 6-8wt%, or 10-30wt%, or 10- 25wt%, or 10-20wt%, or 10-15wt%, or 15-30wt%, or 15-25wt%, or 15-20wt%, or 30-99wt%, or 30-90wt%, or 30-80wt%, or 30-70wt%, or 30-60wt%, or 30-50wt%, or 40-99wt%, or 40-90wt%, or 40-80wt%, or 40-70wt%, or 40-60wt%, or 50- 99wt%, or 50-90wt%, or 50-80wt%, or 50-70wt%, or 60-99wt%, or 60-90wt%, or 60-80wt%, or 70-99wt%, 70-90wt%, or 80-99wt%, or 90-99wt%, or at least 1 wt%, or at least 2 wt%, or at least 3 wt%, or at least 4wt%, or at least 5 wt%, based on the total weight of the cellulose ester microparticles composition.

[0104] In one embodiment or in combination with any other embodiment of this third aspect, the water is present in the stabilized cellulose ester microparticles composition at from 1 -99wt%, or 1-10wt%, or 1 -9wt%, or 1 -8wt%, or 1 -7wt%, or 1 -6wt%, or 2-10wt%, or 2-9wt%, or 2-8wt%, or 2-7wt%, or 2-6wt%, or 3-10wt%, or 3-9wt%, or 3-8wt%, or 3-7wt%, or 3-6wt%, or 4-10w%, or 4-9wt%, or 4-8wt%, or 4-7wt%, or 4-6wt%, or 4-5wt%, or 1-9wt%, or 1 -8wt%, or 1 -7wt%, or 1-6wt%, %, or 1 -5wt%, or 1 -4wt%, or 1 -3wt%, or 1-2wt%, or 2-9wt%, or 2-8wt%, or 2- 7wt%, or 2-6wt%, or 2-5wt%, or 3-9wt%, or 3-8wt%, or 3-7wt%, or 3-6wt%, or 4- 10wt%, or 4-9wt%, or 4-8wt%, or 4-7wt%, or 4-6wt%, or 4-5wt%, or 5-10wt%, or

[0105] 5-9wt%, or 5-8wt%, or 5-7wt%, or 5-6wt%, or 6-10wt%, or 6-9wt%, or 6-8wt%, or 10-30wt%, or 10-25wt%, or 10-20wt%, or 10-15wt%, or 15-30wt%, or 15-25wt%, or 15-20wt%, or 30-99wt%, or 30-90wt%, or 30-80wt%, or 30-70wt%, or 30- 60wt%, or 30-50wt%, or 40-99wt%, or 40-90wt%, or 40-80wt%, or 40-70wt%, or 40-60wt%, or 50-99wt%, or 50-90wt%, or 50-80wt%, or 50-70wt%, or 60-99wt%, or 60-90wt%, or 60-80wt%, or 70-99wt%, 70-90wt%, or 80-99wt%, or 90-99wt%, or at least 1wt%, or at least 2 wt%, or at least 3 wt%, or at least 4wt%, or at least 5 wt%, based on the total weight of the stabilized cellulose ester microparticles composition. The water present in the stabilized cellulose ester microparticles composition can be adjusted by adding water to the composition or by drying the composition by any method known to one of ordinary skill in the art. Nonlimiting examples include by distillation at atmospheric pressure or at a pressure that is lower than atmospheric pressure; by simply applying vacuum; air drying, or by freeze drying the stabilized cellulose ester microparticles composition.

[0106] In one embodiment or in combination with any other embodiment, the at least one organic acid salt comprises an alkali metal cation or an alkaline metal cation.

[0107] In one class of this embodiment, the alkali metal cation is Li+, Na+, or K+, and the alkaline metal cation is Mg2+or Ca2+.

[0108] In one class of this embodiment, the organic acid component of the at least one organic acid salt is derived from a compound of formula I: , wherein: G is a (Ci-8)alkylene, wherein the alkylene is unsubstituted or substituted by 1 to 2 hydroxyl substituents, a (Ci-8)alkenyl, or a phenyl; and n is 0, 1 , or 2. In one class of this embodiment, the compound of formula I is glutaric acid, pimelic acid, azelaic acid, sebacic acid, suberic acid, adipic acid, succinic acid, citric acid, tartaric acid, fumaric acid, terephthalic acid, isophthalic acid, acetic acid, or propionic acid, or lactic acid. In one subclass of this class, the alkali metal cation is Li+, Na+, or K+, and the alkaline metal cation is Mg2+or Ca2+.

[0109] In one embodiment or in combination with any other embodiment, the organic acid salt is sodium succinate, potassium succinate, magnesium succinate, calcium succinate, sodium citrate, potassium citrate, magnesium citrate, calcium citrate, sodium acetate, potassium acetate, magnesium acetate, calcium acetate, sodium lactate, potassium lactate, magnesium lactate, calcium lactate, or a combination thereof.

[0110] In one embodiment or in combination with any other embodiment, the organic acid salt composition is a solid, an aqueous suspension or an aqueous solution. In one class of this embodiment, the organic acid salt composition is an aqueous suspension. In one class of this embodiment, the organic acid salt composition is an aqueous solution. In one class of this embodiment, the organic acid salt composition is a solid. In one class of this embodiment, the organic acid salt composition is an aqueous suspension or an aqueous solution.

[0111] In one embodiment or in combination with any other embodiment of the third aspect, the organic acid salt composition is the aqueous solution, and the applying is conducted by spraying the organic acid salt composition onto the cellulose ester particles composition or mixing the organic acid salt composition with the cellulose ester particles composition. In one class of this embodiment, the applying is conducted by spraying the organic acid salt composition onto the cellulose ester particles in the cellulose ester particles composition. In one class of this embodiment, the applying is conducted by mixing the organic acid salt composition with the cellulose ester particles composition.

[0112] In one embodiment or in combination with any other embodiment of the third aspect, the organic acid salt composition is a solid, an aqueous suspension, and the applying is done by mixing the organic acid salt composition with the cellulose ester particles composition. In one embodiment or in combination with any other embodiment of this third aspect, the organic acid salt composition is a solid, and the applying is done by mixing the organic acid salt composition with the cellulose ester particles or the cellulose ester particles composition. In one embodiment or in combination with any other embodiment of this third aspect, the organic acid salt composition is a solid, and the applying is done by mixing the organic acid salt composition with the cellulose ester particles. In one embodiment or in combination with any other embodiment, the organic acid salt composition is a solid. In one class of this embodiment, the solid is a particulate solid.

[0113] In one embodiment or in combination with any other embodiment, the method further comprises a step (ii) drying the stabilized cellulose ester microparticles composition which is performed after the applying step (i). In one class of this embodiment, the drying is performed by blowing air over the stabilized cellulose ester microparticles composition, wherein the air is heated at or below a temperature of 100°C, or 90°C, or 80°C, or 70°C, or 60°C, or 50°C, or 50°C. In one subclass of this class, the stabilized cellulose ester microparticles composition comprises a water content. In one sub-subclass of this subclass, the water content is less than 15 wt%, or less than 20wt%, less than 10wt%, or less than 9 wt%, or less than 8wt%, or less than 7wt%, or less than 6wt%, or less than 5wt%, or less than 4wt%, or less than 3wt%, or less than 2wt%, or less than 1 wt%.

[0114] In one embodiment or in combination with any other embodiment, the method further comprising a step (iii) filtering the stabilized cellulose ester microparticles composition, which is performed after the applying step (i).

[0115] In one class of this embodiment or in combination with any other embodiment or class, the method further comprises a step (iv) drying the stabilized cellulose ester microparticles composition which is performed after the applying filtering step (iii). In one class of this embodiment, the drying is performed by blowing air over the stabilized cellulose ester microparticles composition, wherein the air is heated at or below a temperature of 100°C, or 90°C, or 80°C, or 70°C, or 60°C, or 50°C, or 50°C. In one subclass of this class, the water is present at less than 15 wt%, or less than 20wt%, less than 10wt%, or less than 9 wt%, or less than 8wt%, or less than 7wt%, or less than 6wt%, or less than 5wt%, or less than 4wt%, or less than 3wt%, or less than 2wt%, or less than 1 wt%. The water present in the stabilized cellulose ester microparticles composition can be adjusted by adding water to the composition or by drying the stabilized cellulose ester microparticles composition by any method known to one of ordinary skill in the art. Nonlimiting examples include by distillation at atmospheric pressure or at a pressure that is lower than atmospheric pressure; by simply applying vacuum; air drying, or by freeze drying the treated cellulose ester particles composition.

[0116] In one embodiment or in combination with any other embodiment, the size reduction process is a mechanical grinding process, or a milling process. In one class of this embodiment, the size reduction process is a mechanical grinding process. In one class of this embodiment, the size reduction process is a milling process. In one subclass of this class, the milling process is jet milling.

[0117] In one embodiment or in combination with any other embodiment, wherein the cellulose ester is a cellulose acetate, a cellulose propionate, a cellulose butyrate, a cellulose acetate propionate, a cellulose acetate butyrate, or a combination thereof.

[0118] In one class of this embodiment, the cellulose ester is a cellulose acetate. In one class of this embodiment, the cellulose ester is a cellulose acetate propionate, a cellulose acetate butyrate, a cellulose propionate, or a cellulose butyrate. In one class of this embodiment, the cellulose ester is a cellulose acetate propionate, or a cellulose acetate butyrate. In one class of this embodiment, the cellulose ester is a cellulose acetate propionate. In one class of this embodiment, the cellulose ester is a cellulose acetate butyrate. In one class of this embodiment, the cellulose ester is a cellulose propionate. In one class of this embodiment, the cellulose ester is a cellulose butyrate.

[0119] In one embodiment or in combination with any other embodiment, the cellulose ester has an average degree of substitution for hydroxyl substituents (“DSOH”) that is at least 0.5, or at least 0.6, or at least 0.7, or at least 0.8, or at least 0.9, or in the range of 0.5 to 1 .0, or in the range of 0.6 to 1 .0, or in the range of 0.7 to 1 .0, or in the range of 0.8 to 1 .0, or in the range of 0.9 to 1 .0.

[0120] In one embodiment or in combination with any other embodiment, the cellulose ester has an average degree of substitution for hydroxyl substituents (“DSOH”) that is in the range of 0.5 to 1 .0, or in the range of 0.6 to 1 .0, or in the range of 0.7 to 1 .0, or in the range of 0.8 to 1 .0, or in the range of 0.9 to 1 .0.

[0121] In one embodiment or in combination with any other embodiment, the cellulose ester has a weight average molecular weight in the range of from 5,000 to 100,000 Da, or 5,000 to 50,000 Da, or 5,000 to 25,000 Da, or 15,000 to 100,000 Da, or 15,000 to 50,000 Da, or 15,000 to 25,000 Da, or 50,000 to 100,000 Da, or 75,000 to 100,000 Da, or 15,000 to 250,000 Da.

[0122] In one embodiment or in combination with any other embodiment disclosed herein, the stabilized cellulose ester microparticles have: (i) a sphericity in the range of 30 to 100 percent, and (ii) a bulk density in the range of 0.2 to 0.7. In one class of this embodiment, the sphericity is in the range of from 30 to 90 percent, in the range of from or in the range of from 30 to 80 percent, or in the range of from 30 to 70 percent, or in the range of from 30 to 60 percent, or in the range of from 30 to 50 percent, or in the range of from 40 to 100 percent, or in the range of from 40 to 90 percent, or in the range of from 40 to 80 percent, or in the range of from 40 to 70 percent, or in the range of from 40 to 60 percent, or in the range of from 40 to 50 percent, or in the range of from 50 to 100 percent, or in the range of from 60 to 100 percent, or in the range of from 70 to 100 percent, or in the range of from 80 to 100 percent, or in the range of from 90 to 100 percent.

[0123] In one embodiment or in combination with any other embodiment of the third aspect, the cellulose ester particles and the stabilized cellulose ester microparticles further comprise a plasticizer. The plasticizer reduces the melt temperature, the Tg, and / or the melt viscosity of the cellulose ester. In one class of this embodiment or in combination with any other embodiment, class or subclass of the third aspect, the plasticizer is triacetin, triethyl citrate, polyethylene glycol), Benzoflex, propylene glycol, polysorbatemsucrose octaacetate, acetylated triethyl citrate, acetyl tributyl citrate, Admex, tripropionin, Scandiflex, poloxamer copolymers, polyethylene glycol succinate, diisobutyl adipate, polyvinyl pyrollidone, and glycol tribenzoate.

[0124] In one class of this embodiment or in combination with any other embodiment, class or subclass of this third aspect, the plasticizer is present in an amount of from 1 to 40 wt%, or 1 to 30 wt%, or 1 to 20 wt%, or 1 to 10 wt%, or 1 to 5 wt%, or 5 to 40 wt%, or 5 to 30 wt%, or 5 to 20 wt%, or 5 to 10 wt%, or 5 to 5 wt%, or 10 to 40 wt%, or 10 to 30 wt%, or 10 to 20 wt%, or 10 to 10 wt%, or 10 to 5 wt%, 15 to 40 wt%, or 15 to 30 wt%, or 15 to 20 wt%, or 15 to 10 wt%, or 15 to 5 wt%, based on the weight of the cellulose ester microparticles.

[0125] In one class of this embodiment, the plasticizer is a biodegradable plasticizer. Some examples of biodegradable plasticizers include triacetin, triethyl citrate, acetyl triethyl citrate, polyethylene glycol, the benzoate-containing plasticizers such as the Benzoflex™ plasticizer series, poly (alkyl succinates) such as poly (butylene succinate), polyethersulfones, adipate-based plasticizers, soybean oil epoxides such as the Paraplex™ plasticizer series, sucrose-based plasticizers, dibutyl sebacate, tributyrin, sucrose acetate isobutyrate, the Resolflex™ series of plasticizers, triphenyl phosphate, glycolates, polyethylene glycol), 2,2,4-trimethylpentane-1 ,3-diyl bis(2-methylpropanoate), and polycaprolactones.

[0126] In one embodiment or in combination with any other embodiment, class or subclass of this third aspect, the composition further comprises at least one biodegradable polymer that is different than the cellulose ester.

[0127] In one class of this embodiment or in combination with any other embodiment of this third aspect, class or subclass, the biodegradable polymer is chosen from polyhydroxyalkanoates (PHAs and PHBs), poly(lactic acid) (PLA), polycaprolactone polymers (PCL), poly(butylene adipate co-terephthalate) (PBAT), polyethylene succinate) (PES), poly(vinyl acetates) (PVAs), poly(butylene succinate) (PBS) and copolymers [such as poly(butylene succinate-co-adipate) (PBSA)], other cellulose esters, cellulose ethers, starch, proteins, derivatives thereof, and combinations thereof.

[0128] The present application also discloses a composition of a fourth aspect, comprising: (i) cellulose ester microparticles, wherein the cellulose ester microparticles exhibit an average particle size of from 5 to 30 microns, wherein the cellulose ester microparticles comprise a cellulose ester; (ii) 0.1 to 2.0 wt% of an at least one organic acid salt, based on the total weight of the composition; and (iii) less than 10wt% of water, based on the total weight of the composition.

[0129] In one embodiment or in combination with any other embodiment, class, or subclass, the cellulose ester microparticles exhibit an average particle size of from 1 to 30 microns.

[0130] In one embodiment or in combination with any other embodiment of this second aspect, the at least one organic acid salt is present at from 0.1 -2.0wt%, or 0.1-1 .5wt%, or 0.1 -1.0wt%, or 0.1 -0.5wt%, or 0.2-1 ,5wt%, or 0.2-1 .0wt%, or 0.2-0.5wt%, or 0.3-2wt%, or 0.3-1 .5wt%, or 0.3-1 .0wt%, or 0.3-0.5wt%, or 0.4- 2wt%, or 0.4-1 ,5wt%, or 0.4-1 .0wt%, or 0.4-0.5wt%, 1 -2wt%, 1 -1.5wt%, based on the total weight of the composition.

[0131] In one embodiment or in combination with any other embodiment of the fourth aspect, the water is present in the composition at less than 9.9wt%, or less than 9wt%, or less than 8 wt%, or less than 7wt%, or less than 6wt%, or less than 5wt%, or less than 4wt%, or less than 3wt%, or less than 2wt%, or less than 1wt%, or in the range of from 1-9.9wt%, or in the range of from 2-9.9wt%, or in the range of from 3-9.9%, or in the range of form 4-9.9wt%, or in the range of from 5-9.9wt%, or in the range of from 1-9wt%, or in the range of from 2-9.9wt%, or in the range of from 2-9wt%, or in the range of from 3-9wt%, or in the range of form 4-9wt%, or in the range of from 5-9wt%, or in the range of from 6-9wt%, or in the range of from 7-9wt%, or in the range of from 1-8wt%, or in the range of from 2-8wt%, or in the range of from 3-8wt%, or in the range of form 4-8wt%, or in the range of from 5-8wt%, or in the range of from 6-8wt%, or in the range of from 1 -7wt%, or in the range of from 2-7wt%, or in the range of from 3-7wt%, or in the range of form 4-7wt%, or in the range of from 5-7wt%, or in the range of from 1 -6wt%, or in the range of from 2-6wt%, or in the range of from 3-6wt%, or in the range of form 4-6wt%, or in the range of from 5-6wt%, or in the range of from 1 -5wt%, or in the range of from 2-5wt%, or in the range of from 3-5wt%, or in the range of form 4-5wt%, based on the total weight of the composition

[0132] In one embodiment or in combination with any other embodiment of the fourth aspect, the at least one organic acid salt comprises an alkali metal cation or an alkaline metal cation.

[0133] In one class of this embodiment, the alkali metal cation is Li+, Na+, or K+, and the alkaline metal cation is Mg2+or Ca2+.

[0134] In one class of this embodiment, the organic acid component of the at least one organic acid salt is derived from a compound of formula I: , wherein: G is a (Ci-8)alkylene, wherein the alkylene is unsubstituted or substituted by 1 to 2 hydroxyl substituents, a (Ci-8)alkenyl, or a phenyl; and n is 0, 1 , or 2. In one class of this embodiment, the compound of formula I is glutaric acid, pimelic acid, azelaic acid, sebacic acid, suberic acid, adipic acid, succinic acid, citric acid, tartaric acid, fumaric acid, terephthalic acid, isophthalic acid, acetic acid, or propionic acid, or lactic acid. In one subclass of this class, the alkali metal cation is Li+, Na+, or K+, and the alkaline metal cation is Mg2+or Ca2+.

[0135] In one embodiment or in combination with any other embodiment of the fourth aspect, the organic acid salt is sodium succinate, potassium succinate, magnesium succinate, calcium succinate, sodium citrate, potassium citrate, magnesium citrate, calcium citrate, sodium acetate, potassium acetate, magnesium acetate, calcium acetate, sodium lactate, potassium lactate, magnesium lactate, calcium lactate, or a combination thereof.

[0136] In one embodiment or in combination with any other embodiment of the fourth aspect, wherein the cellulose ester is a cellulose acetate, a cellulose propionate, a cellulose butyrate, a cellulose acetate propionate, a cellulose acetate butyrate, or a combination thereof.

[0137] In one class of this embodiment, the cellulose ester is a cellulose acetate. In one class of this embodiment, the cellulose ester is a cellulose acetate propionate, a cellulose acetate butyrate, a cellulose propionate, or a cellulose butyrate. In one class of this embodiment, the cellulose ester is a cellulose acetate propionate, or a cellulose acetate butyrate. In one class of this embodiment, the cellulose ester is a cellulose acetate propionate. In one class of this embodiment, the cellulose ester is a cellulose acetate butyrate. In one class of this embodiment, the cellulose ester is a cellulose propionate. In one class of this embodiment, the cellulose ester is a cellulose butyrate.

[0138] In one embodiment or in combination with any other embodiment of the fourth aspect, the cellulose ester has an average degree of substitution for hydroxyl substituents (“DSOH”) that is at least 0.5, or at least 0.6, or at least 0.7, or at least 0.8, or at least 0.9, or in the range of 0.5 to 1 .0, or in the range of 0.6 to 1 .0, or in the range of 0.7 to 1 .0, or in the range of 0.8 to 1 .0, or in the range of 0.9 to 1.0.

[0139] In one embodiment or in combination with any other embodiment of the fourth aspect, the cellulose ester has an average degree of substitution for hydroxyl substituents (“DSOH”) that is in the range of 0.5 to 1 .0, or in the range of 0.6 to 1 .0, or in the range of 0.7 to 1 .0, or in the range of 0.8 to 1 .0, or in the range of 0.9 to 1 .0. In one embodiment or in combination with any other embodiment of the fourth aspect, the cellulose ester has a weight average molecular weight in the range of from 5,000 to 100,000 Da, or 5,000 to 50,000 Da, or 5,000 to 25,000 Da, or 15,000 to 100,000 Da, or 15,000 to 50,000 Da, or 15,000 to 25,000 Da, or 50,000 to 100,000 Da, or 75,000 to 100,000 Da, or 15,000 to 250,000 Da.

[0140] In one embodiment or in combination with any other embodiment of the fourth aspect, wherein stabilized cellulose ester microparticles have: (i) a sphericity in the range of 30 to 100 percent, and (ii) a bulk density in the range of 0.2 to 0.7. In one class of this embodiment, the sphericity is in the range of from 30 to 90 percent, in the range of from or in the range of from 30 to 80 percent, or in the range of from 30 to 70 percent, or in the range of from 30 to 60 percent, or in the range of from 30 to 50 percent, or in the range of from 40 to 100 percent, or in the range of from 40 to 90 percent, or in the range of from 40 to 80 percent, or in the range of from 40 to 70 percent, or in the range of from 40 to 60 percent, or in the range of from 40 to 50 percent, or in the range of from 50 to 100 percent, or in the range of from 60 to 100 percent, or in the range of from 70 to 100 percent, or in the range of from 80 to 100 percent, or in the range of from 90 to 100 percent.

[0141] In one embodiment or in combination with any other embodiment of the fourth aspect, the cellulose ester particles and the stabilized cellulose ester microparticles further comprise a plasticizer. The plasticizer reduces the melt temperature, the Tg, and / or the melt viscosity of the cellulose ester.

[0142] In one class of this embodiment or in combination with any other embodiment, class or subclass of the fourth aspect, the plasticizer is triacetin, triethyl citrate, polyethylene glycol), Benzoflex, propylene glycol, polysorbatemsucrose octaacetate, acetylated triethyl citrate, acetyl tributyl citrate, Admex, tripropionin, Scandiflex, poloxamer copolymers, polyethylene glycol succinate, diisobutyl adipate, polyvinyl pyrollidone, and glycol tribenzoate. In one class of this embodiment or in combination with any other embodiment, class or subclass of this fourth aspect, the plasticizer is present in an amount of from 1 to 40 wt%, or 1 to 30 wt%, or 1 to 20 wt%, or 1 to 10 wt%, or 1 to 5 wt%, or 5 to 40 wt%, or 5 to 30 wt%, or 5 to 20 wt%, or 5 to 10 wt%, or 5 to 5 wt%, or 10 to 40 wt%, or 10 to 30 wt%, or 10 to 20 wt%, or 10 to 10 wt%, or 10 to 5 wt%, 15 to 40 wt%, or 15 to 30 wt%, or 15 to 20 wt%, or 15 to 10 wt%, or 15 to 5 wt%, based on the weight of the cellulose ester microparticles.

[0143] In one class of this embodiment, the plasticizer is a biodegradable plasticizer. Some examples of biodegradable plasticizers include triacetin, triethyl citrate, acetyl triethyl citrate, polyethylene glycol, the benzoate-containing plasticizers such as the Benzoflex™ plasticizer series, poly (alkyl succinates) such as poly (butylene succinate), polyethersulfones, adipate-based plasticizers, soybean oil epoxides such as the Paraplex™ plasticizer series, sucrose-based plasticizers, dibutyl sebacate, tributyrin, sucrose acetate isobutyrate, the Resolflex™ series of plasticizers, triphenyl phosphate, glycolates, polyethylene glycol), 2,2,4-trimethylpentane-1 ,3-diyl bis(2-methylpropanoate), and polycaprolactones.

[0144] In one embodiment or in combination with any other embodiment, class or subclass of this fourth aspect, the composition further comprises at least one biodegradable polymer that is different than the cellulose ester.

[0145] In one class of this embodiment or in combination with any other embodiment of this fourth aspect, class or subclass, the biodegradable polymer is chosen from polyhydroxyalkanoates (PHAs and PHBs), poly(lactic acid) (PLA), polycaprolactone polymers (PCL), poly(butylene adipate co-terephthalate) (PBAT), polyethylene succinate) (PES), poly(vinyl acetates) (PVAs), poly(butylene succinate) (PBS) and copolymers [such as poly(butylene succinate-co-adipate) (PBSA)], other cellulose esters, cellulose ethers, starch, proteins, derivatives thereof, and combinations thereof. The present application in a fifth aspect discloses a personal care composition comprising any of the previously disclosed stabilized cellulose ester microparticles.

[0146] In one embodiment or in combination with any other embodiment in the fifth aspect, the personal care composition is a foundation, a sunscreen, a lipstick, a mascara, an eye shadow, a lotion, a dry shampoo, a liquid shampoo, a body wash, a lotion, a hair conditioner, a skin moisturizer, a face wash, a tablet, a foot powder, a baby powder, a shaving cream, or a shaving gel.

[0147] In one embodiment or in combination with any other embodiment mentioned in the fifth aspect, the personal care composition can be a loose powder, a compacted powder, a gel, an emulsion, a liquid, or an aerosol.

[0148] In one embodiment or in combination with any other embodiment mentioned in the fifth aspect, the personal care composition comprises at least 1 , 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 99 weight percent of at least one, two, three, four, or five personal care composition additives.

[0149] Additionally, or in the alternative, the personal care composition can comprise less 30 than 99, 95, 90, 85, 80, 75, 70, 65, 60, 55, or 50 weight percent of at least one, two, three, four, or five personal care composition additives. For example, the personal care composition can comprise 1 to 99, 1 to 95, 1 to 90, 1 to 85, 1 to 80, 5 to 99, 5 to 95, 5 to 90, 5 to 85, 10 to 99, 10 to 95, 10 to 85, 10 to 80, 15 to 99, 15 to 95, 15 to 90, 15 to 85, or 15 to 80 weight percent of at least one, two, three, four, or five personal care composition additives.

[0150] Generally, the personal care composition additives can include a solvent, a colorant, an oil, a wax, a fatty acid, an alcohol, an ester, a hydrocarbon, a silicone oil, a surfactant, a metal soap, a moisturizer, a thickener, a UV absorber, an antioxidant, an oil absorbent, an exfoliant, water, or a combination thereof. In one embodiment or in combination with any other embodiment mentioned herein, the colorant comprises a pigment (e.g., an organic pigment and / or an inorganic pigment) and / or a dye.

[0151] In one embodiment or in combination with any other embodiment in the sixth aspect, the oil comprises triglycine, soybean oil, cocoa butter, palm oil, palm kernel oil, hardened oil, and / or hardened castor oil.

[0152] In one embodiment or in combination with any other embodiment mentioned in the sixth aspect, the wax comprises carnauba wax, candelilla wax, lanolin, lanolin, candelilla wax, cotton wax, Montan wax, Kapok wax, lanolin acetate, lanolin, and / or lanolin fatty acid isopropyl.

[0153] In one embodiment or in combination with any other embodiment mentioned in the fifth aspect, the fatty acid comprises lauric acid, myristic acid, palmitic acid, stearic acid, isostearic acid, behenic acid, oleic acid, undecylenic acid, linoleic acid, eicosapentaenoic acid (EPA), and / or docosahexaenoic acid.

[0154] In one embodiment or in combination with any other embodiment mentioned in the fifth aspect, the alcohol comprises cetyl alcohol, stearyl alcohol, isostearyl alcohol, 2-octyldodecanol, lauryl alcohol, behenyl alcohol, myristyl alcohol, oleyl alcohol, and / or cetostearyl alcohol.

[0155] In one embodiment or in combination with any other embodiment mentioned in the fifth aspect, the ester comprises isopropyl myristate, 2- octyldodecyl myristate, cetyl 2-ethylhexanoate, diisostearyl malate, tripropylene glycol dineopentate, isononyl isononanoate, isotorideyl isononanoate, cetyl octanoate, isocetyl palmitate, butyl stearate, hexyl laurate, myristyl myristate, decyl oleate, hexyl decyl dimethyloctanate, cetyl lactate, myristyl lactate, lanolin acetate, isosetyl stearate, isosetyl isostearate, cholesteryl 12-hydroxystearate, di- 2-ethylhexanoic acid ethylene glycol, dipentaerythritol fatty acid ester, monoisostearate N-alkylglycol, dicaprate neopentyl glycol, di-2- heptylundecanoate glycerin, tri-2-ethylhexanoate trimethylpropane, Trimethylolpropane triisostearate, pentaerythritol tetra-2-ethylhexanoate, glycerin tri-2-ethylhexanoate, glycerin trioctanoate, glycerin triisopalmitate, trimethylolpropane triisostearate, ethylhexyl palmitate, glycerin trimyristate, tri-2- heptylundecanoic acid glyceride, castor oil fatty acid methyl ester, oleyl oleate, acetoglyceride, 2-heptylundecyl palmitate, diisobutyl adipate, N-lauroyl-L- Glutamic hexyldecyl palmitate, adipate hexyldecyl, diisopropyl sebacate, ethylhexyl succinate, and / or triethyl citrate.

[0156] In one embodiment or in combination with any other embodiment mentioned in the fifth aspect, the hydrocarbon comprises paraffin, petrolatum, and / or microcrystalline wax.

[0157] In one embodiment or in combination with any other embodiment mentioned in the fifth aspect, the surfactant comprises an anionic surfactant, a cationic surfactant, and / or a nonionic surfactant.

[0158] In one embodiment or in combination with any other embodiment mentioned in the fifth aspect, the thickener comprises guar gum, pectin, starch, gelatin, collagen, cellulosic derivatives, and / or mannan.

[0159] Disintegration vs. Biodegradation

[0160] In general, degradation is followed by the determination of parameters such as DOC (dissolved organic carbon), CO2 production and oxygen uptake. There are three main methods for testing the biodegradation of a material: the Sturm method, respirometry method, and the radio-labeled14C atom test method. The Sturm method precisely measures carbon dioxide production through a change in pressure. The respirometry test precisely measures the oxygen consumption over 60 days. Finally, the radio-labeled 14C atom test determines14C conversion to14CC>2. All three methods can be used under aquatic or composting conditions if the right equipment is used.

[0161] Freshwater Modified Sturm Test (OECD 301 B) - The amount of carbon dioxide (CO2) produced as a percentage of theoretical yield (based on total organic carbon analysis) is used as a basis for assessing whether the material biodegrades. CO2 is measured by way of a sodium hydroxide trap. The study is run for a minimum of 28 days and may be continued if the yield of CO2 is showing signs of increase towards the end of the 28-day period.

[0162] Biodegradation Test - O2 Consumption (OECD 301 F) may be used to monitor biodegradation of polymeric materials. OECD 301 F is an aquatic aerobic biodegradation test that determines the biodegradability of a material by measuring oxygen consumption. OECD 301 F is most often used for insoluble and volatile materials that are challenged by OECD 301 B testing. The purity or proportions of major components of the test material is important for calculating the Theoretical Oxygen Demand (ThOD). Like other OECD 301 test methods, the standard test duration for OECD 301 F is a minimum of 28 days and can measure ready or inherent biodegradability. A solution or suspension, of the test substance in a mineral medium is inoculated and incubated under aerobic conditions in the dark or in diffuse light. A reference compound (typically sodium acetate or sodium benzoate) is run in parallel to check the operation of the procedures.

[0163] There are three classifications of biodegradability: readily biodegradable, inherently biodegradable, and not biodegradable. A material is readily biodegradable if it reaches >60% of its theoretical oxygen demand within 28 days. Inherently biodegradable materials also reach the 60% level, but only after the 28-day window has passed. Normally, the test for materials that are readily biodegradable lasts for 28 days, while a prolonged test period may be used to classify materials as inherently biodegradable.

[0164] The OxiTop method is a modified Sturm method to analyze biodegradation while reporting biodegradability as oxygen consumption, converting the pressure from the CO2 produced during the test to BOD, biological oxygen demand. OxiTop provides precise measurement in an easy-to-use format for aquatic biodegradation. Biological Oxygen Demand [BOD] was measured over time using an OxiTop® Control OC 1 10 Respirometer system. This is accomplished by measuring the negative pressure that develops when oxygen is consumed in the closed bottle system. NaOH tablets are added to the system to collect the CO2 given off when O2 is consumed. The CO2 and NaOH react to form Na2COs, which pulls CO2 out of the gas phase and causes a measurable negative pressure. The OxiTop measuring heads record this negative pressure value and relay the information wirelessly to a controller, which converts CO2 produced into BOD due to the 1 :1 ratio. The measured biological oxygen demand can be compared to the theoretical oxygen demand of each test material to determine the percentage of biodegradation. The OxiTop can be used to screen materials for ready or inherent biodegradability.

[0165] In one embodiment or in combination with any other embodiment, class, or subclass, the stabilized cellulose ester microparticles in any aspect disclosed herein exhibit at least 40% biodegradability, at least 45% biodegradability, or at least 50% biodegradability, or at least 55% biodegradability, at least 60% biodegradability, or at least 65% biodegradability, or at least 70% biodegradability, or at least 75% biodegradability, or at least 80% biodegradability, or at least 85% biodegradability, at 60 days according to the OECD 301 F test method.

[0166] In one embodiment or in combination with any other embodiment, class, or subclass, the cellulose esters in any aspect disclosed herein exhibit at least 40% biodegradability, at least 45% biodegradability, or at least 50% biodegradability, or at least 55% biodegradability, at least 60% biodegradability, or at least 65% biodegradability, or at least 70% biodegradability, or at least 75% biodegradability, or at least 80% biodegradability, or at least 85% biodegradability, at 60 days according to the OECD 301 F test method.

[0167] Specific Embodiments

[0168] Embodiment 1. A method, comprising: (i) applying an organic acid salt composition comprising an at least one organic acid salt to a cellulose ester particles composition comprising: (1) cellulose ester particles which comprise a cellulose ester, and (2) water, to produce a treated cellulose ester particles composition comprising: (1) treated cellulose ester particles, (2) at least one organic salt, and (2) water, wherein the cellulose ester particles and the treated cellulose ester particles have an average particle size of 50-500 microns; and (ii) subjecting the treated cellulose ester particles composition to a size reduction process to produce a stabilized cellulose ester microparticles composition comprising: (1 ) stabilized cellulose ester microparticles, (2) at least one organic acid salt, and (3) water, wherein the stabilized cellulose ester microparticles have an average particle size of from 1 -30 microns, and wherein the stabilized cellulose ester microparticles are biodegradable.

[0169] Embodiment 2. The method of Embodiment 1 , wherein the organic acid salt composition is a solid, an aqueous suspension or an aqueous solution.

[0170] Embodiment 3. The method of Embodiment 2, wherein the organic acid salt composition is the aqueous solution, and the applying is conducted by spraying the organic acid salt composition onto the cellulose ester particles in the cellulose ester particles composition or mixing the organic acid salt composition with the cellulose ester particles composition; or the applying is conducted by spraying the organic acid salt composition onto the cellulose ester particles composition.

[0171] Embodiment 4. The method of Embodiment 3, wherein the organic acid salt composition is a solid or an aqueous suspension, and the applying is done by mixing the organic acid salt composition with the cellulose ester particles composition.

[0172] Embodiment 5. The method of any one of Embodiments 1 -4, wherein the water in the cellulose ester particles composition is at least 1wt%, based on the total weigh of the cellulose ester particles composition and the organic acid salt composition is a solid. Embodiment 6. The method of any one of Embodiments 1 -5, wherein the method further comprises a step (iii) filtering the treated cellulose ester compositions; after the applying step (i) but before the subjecting step (ii).

[0173] Embodiment 7. The method of Embodiment 6, wherein the method further comprises a step (iv) drying the treated cellulose ester composition; after the filtering step (iii), but before the subjecting step (ii).

[0174] Embodiment 8. The method of any one of Embodiments 1 -7, wherein the size reduction process is a mechanical grinding process, or a milling process.

[0175] Embodiment 9. A method, comprising: (i) applying an organic acid salt composition comprising an at least one organic acid salt to a cellulose ester microparticles composition, comprising: (1 ) cellulose ester microparticles which comprise a cellulose ester, and (2) water, to produce a stabilized cellulose ester microparticles composition which comprises: (1 ) stabilized cellulose ester microparticles, (2) at least one organic acid salt, and (3) water, wherein the cellulose ester microparticles have an average particle size of from 1-30 microns, the stabilized cellulose ester microparticles have an average particle size of 1 -30 microns, and the stabilized cellulose ester microparticles are biodegradable.

[0176] Embodiment 10. The method of Embodiment 9, wherein the organic acid salt composition is a solid, an aqueous suspension or an aqueous solution.

[0177] Embodiment 11 . The method of Embodiment 10, wherein the organic acid salt composition is the aqueous solution, and the applying is conducted by: (i) spraying the organic acid salt composition onto the cellulose ester microparticles composition, or (ii) mixing the organic acid salt composition with the cellulose ester microparticles composition.

[0178] Embodiment 12. The method of Embodiment 11 , wherein the organic acid salt composition is a solid or an aqueous suspension, and the applying is done by mixing the organic acid salt composition with the cellulose ester microparticles composition. Embodiment 13. The method of any one of Embodiments 1 1-12, wherein the water in the cellulose ester microparticles composition is at least 1 wt% based on the total weight of the cellulose ester particles composition and the organic acid salt composition is a solid.

[0179] Embodiment 14. The method of any one of Embodiments 1 1-13, wherein the method further comprises a step (ii) drying the stabilized cellulose cellulose ester microparticles composition; which is performed after the applying step (i).

[0180] Embodiment 15. The method of any one of Embodiments 1 1-14, wherein the method further comprises a step (iii) filtering the stabilized cellulose ester microparticles composition, wherein the stabilized cellulose ester microparticles composition comprises a water content; which is performed after the applying step (i).

[0181] Embodiment 16. A composition, comprising: (i) cellulose ester particles, wherein the cellulose ester particles exhibit an average particle size of from 50 to 500 microns, wherein the cellulose ester particles comprise a cellulose ester; (ii) 0.1 to 2.0 wt% of an at least one organic acid salt, based on the total weight of the composition; and (iii) less than 10wt% of water, based on the total weight of the composition.

[0182] Embodiment 17. A composition, comprising: (i) cellulose ester microparticles, wherein the cellulose ester microparticles exhibit an average particle size of from 5 to 30 microns, wherein the cellulose ester microparticles comprise a cellulose ester; (ii) 0.1 to 2.0 wt% of an at least one organic acid salt, based on the total weight of the composition; and (iii) less than 10wt% of water, based on the total weight of the composition.

[0183] Embodiment 18. The composition of any one of Embodiments 1 -17, wherein the composition is a personal care composition.

[0184] Embodiment 19. The method or composition of any one of Embodiments 1 -18, wherein the at least one organic acid salt comprises an alkali metal cation or an alkaline metal cation. Embodiment 20. The method or composition of Embodiment 19, wherein the alkali metal cation is Li+, Na+, or K+, and the alkaline metal cation is Mg2+or Ca2+.

[0185] Embodiment 21 . The method or composition of Embodiment 20, wherein the organic acid component of the at least one organic acid salt is derived from a compound of formula I wherein: G is a (Ci-8)alkylene, wherein the alkylene is unsubstituted or substituted by 1 to 2 hydroxyl substituents, a (Ci- 8)alkenyl, or a phenyl; and n is 0, 1 , or 2.

[0186] Embodiment 22. The method or composition of any one of Embodiments 1 -21 , wherein the compound of formula I is glutaric acid, pimelic acid, azelaic acid, sebacic acid, suberic acid, adipic acid, succinic acid, citric acid, tartaric acid, fumaric acid, terephthalic acid, isophthalic acid, acetic acid, or propionic acid, or lactic acid.

[0187] Embodiment 23. The method or composition of any one of Embodiments 1 -22, wherein the organic acid salt is sodium succinate, potassium succinate, magnesium succinate, calcium succinate, sodium citrate, potassium citrate, magnesium citrate, calcium citrate, sodium acetate, potassium acetate, magnesium acetate, calcium acetate, sodium lactate, potassium lactate, magnesium lactate, or calcium lactate.

[0188] Embodiment 24. The method or composition of any one of Embodiments 1 -23, wherein the cellulose ester is a cellulose acetate, a cellulose propionate, a cellulose butyrate, a cellulose acetate propionate, a cellulose acetate butyrate, or a combination thereof.

[0189] Embodiment 25. The method or composition of any one of Embodiments 1 -24, wherein the cellulose ester has an average degree of substitution for hydroxyl substituents (“DSOH”) that is at least 0.5, or at least 0.6, or at least 0.7, or at least 0.8, or at least 0.9.

[0190] Embodiment 26. The method or composition of any one of Embodiments 1 -25, wherein the cellulose ester microparticles further comprise a plasticizer. Embodiment 27. The method or composition of any one of Embodiments

[0191] 1 -26, wherein the stabilized cellulose ester microparticles have: (i) a sphericity in the range of 30 to 100 percent, and (ii) a bulk density in the range of 0.2 to 0.7.

[0192] Embodiment 28. The composition of any one of Embodiments 18-27, wherein the personal care composition is a foundation, a sunscreen, a lipstick, a mascara, an eye shadow, a lotion, a dry shampoo, a liquid shampoo, a body wash, a lotion, a hair conditioner, a skin moisturizer, a face wash, a tablet, a foot powder, a baby powder, a shaving cream, or a shaving gel.

[0193] Embodiment 29. The composition of Embodiment 28, wherein the personal care composition is a loose powder, a compacted powder, a gel, an emulsion, a liquid, or an aerosol.

[0194] EXPERIMENTAL SECTION

[0195] Abbreviations

[0196] °C is degree(s) Celsius; CE is cellulose ester; g is gram; mmHg is millimeter(s) mercury; rpm is revolutions per minute; h is hour(s); MgSuc is magnesium succinate; aq is aqueous; CaLac is calcium lactate; NaOAc is sodium acetate; pL is microliter(s); soln is solution; Mth is month(s); APS is average particle size or D(4,3) mean diameter (microns); %PSD is percent particle size distribution;

[0197] |ApH | is the absolute value of the change in the pH.

[0198] Preparation of Stabilizer Salt solutions

[0199] Table 1 shows the salt solutions that were made. Salts of organic dicarboxylic acids were made by neutralizing the acid with an equimolar amount of an oxide, hydroxide or carbonate of a divalent cation. The solubility of the solution at 25°C was assessed visually. When the divalent cation is magnesium, calcium or barium, the salts were soluble at 0.1 M at 25°C as summarized in Table 1 .

[0200] A small amount of sulfuric acid was added to select 0.1 M salt solutions in Table 1 to allow insoluble CaSC>4 to precipitate. The amount was estimated from elemental analysis of the MgO to measure the actual Fe and Ca . When 18 pL of concentrated sulfuric acid was added to 500 ml of a 0.1 M solution of Mg-adipate or Mg-succinate, the solution formed a very fine white suspended precipitate over time, but the pH did not change from 5. After ~2h, the solution was filtered through a 0.2 micron filter into a sterile bottle. The salt solution was clear, colorless and sterile. Table 1 .

[0201] Preparation of Stabilized CE Particles

[0202] I. Preparation of Cellulose Ester (Ex 1) General Procedure for the Preparation of Cellulose Esters

[0203] Cellulose mixture [cellulose and AcOH] (“Cellulose Mixture”) and sulfuric acid, AC2O and BU2O (“Acylation Solution”) was cooled to 30°C in an agitated reactor, and the reaction mixture cooled to around 7°C with agitation. Additional sulfuric acid was added to a target amount, and the resulting reaction mixture, while stirring, was warmed to 45 °C - 65°C until the reagents were exhausted.

[0204] The reaction mixture treated with aqueous AcOH and BuOH (“Hydrolysis Solution”) and stirred at 68°C under the Hydrolysis Conditions. Then, the reaction mixture was then quenched, neutralized, precipitated, washed and dried by common methods. Degree of Substitution

[0205] The degree of substitution for the substituents on the cellulose ester backbone is calculated using proton nuclear magnetic resonance spectroscopy. Gel permeation chromatography is performed on cellulose esters in stabilized tetrahydrofuran. The instrument is an Agilent 1260 which consists of a degasser, isocratic pump with a flow rate of 1 .0 milliliters per minute, autosampler with an injection volume of 25 microliters, a column oven set at 28°C and a refractive index detector at 28°C. The column set consists of an Agilent PLgel 5 micron guard, Mixed-C and Oligopore in series. The system is calibrated with monodisperse polystyrene standard ranging from approximately 4 million to 162 molecular weight. The sample is prepared by weighing approximately 25 milligrams of sample in 10 milliliters of solvent with the addition of 10 microliters of toluene to be used as a flow rate marker, add a stir bar into an 8-dram screw cap vial and stir until dissolution.

[0206] Molecular Weight

[0207] The molecular weight is determined by gel permeation chromatography. Gel permeation chromatography is performed on cellulose esters in stabilized tetrahydrofuran. The instrument is an Agilent 1260 which consists of a degasser, isocratic pump with a flow rate of 1 .0 milliliters per minute, autosampler with an injection volume of 25 microliters, a column oven set at 28°C and a refractive index detector at 28°C. The column set consists of an Agilent PLgel 5 micron guard, Mixed-C and Oligopore in series. The system is calibrated with monodisperse polystyrene standard ranging from approximately 4 million to 162 molecular weight. The sample is prepared by weighing approximately 25 milligrams of sample in 10 milliliters of solvent with the addition of 10 microliters of toluene to be used as a flow rate marker, add a stir bar into an 8-dram screw cap vial and stir until dissolution. Cellulose Acetate Butyrate (Ex 1): MW=78K, DStot=2.1 , DSAC=1 .9, DSBU=0.2, DSOH=0.9.

[0208] Ex 1 was prepared by adapting the procedure for the preparation of cellulose esters using the reagents in Table 2

[0209] Table 2.

[0210] II. Cellulose Acetate Butyrate Microparticles (Ex 1A): Dio=3.2pm; D5o=6.5pm; D90=11 .8pm; APS-7.01 ; Span-1 .3; %PSD(2-20pm)=98% Jet Milling Process

[0211] There are multiple jet-milling configurations that can be used to reduce the size of particles. Such configurations are discussed in A. Chamayou and J. A. Dodds, Air Jet Milling, Handbook of Powder Technology, volume 12, Chapter 8, 2007 (“Chamayou”). Fig. 7 of Chamayou provides an example of a fluidized bed opposed jet mill that can be used to reduce the size of the cellulose ester particles described below in Table 3. The jet-milling process was used to reduce cellulose ester average particle size from 300-900 pm to ~10pm. Fluidized bed opposed jet mills operates as follows: The cellulose ester is placed into a hopper and introduced into the top of the mill (“FEED IN”) typically though a double valve arrangement (or through an injector). The cellulose ester particles fall by gravity to the bottom of the mill where they are swept up into one of three high pressure air streams that are geometrically oriented towards one another thus forming the so-called “pulverizing zone.” Within the pulverizing zone, the cellulose ester particles are size reduced via interparticle collisions. The size-reduced particles are then conveyed upwards by mass transport in the vertical airstream (fluidized bed) ultimately carrying them into the classifier. The classifier allows particles below the desired minimum size to be removed from the mill (“FINE OUT”).

[0212] Particles that are above the maximum size are excluded from the classifier and returned to the fluidized bed eventually falling back down into the pulverizing zone for further size reduction. Particles that fall within the desired size range are ejected from the classifier into an appropriate product container. Many control parameters exist for optimizing productivity, particle size and particle size distribution shape, including but not necessarily limited to, classifier rotor speed, air nozzle pressure, and bed level.

[0213] The particle size measurements for the particles and be determined using a Malvern Mastersizer 3000 from Malvern Panalytical. “Monomodal particle size distribution” refers to a particle size distribution for a material that only has a single notable peak of size distribution. This is in contrast to multi-modal particle size distributions, which will have two or more peaks of particle size distributions. The “span” of the monomodal peak may be measured using the D10, D50, and D90 values of the particles using the following formula:

[0214] (D90 - DIO) / D5O-

[0215] III. Stabilized CE microparticles

[0216] CE particles 1 A were stabilized with different salt solutions at 0.5 wt% or 1 .0 wt% solids relative to the dry weight of the CE particles.

[0217] Ex 1A.1 : CAB Particles stabilized with Magnesium succinate

[0218] A slurry (50 g) is made by adding a 1 .4% aqueous magnesium succinate solution to CAB (14.3 g). The slurry is then dried in an oil-jacketed sigma-blade mixer with stirring (50 rpm, 75°C, 400 mmHg) for 16 h. Ex 1 A.2 is made by adapting the procedure for the preparation of Ex

[0219] 1A.1.

[0220] Table 3.

[0221] Preparation of NaOAc Stabilized CAB (Ex 1A) Microparticles: Ex 1A.3

[0222] NaOAc (0.25 g) was dissolved in water (105.0g) to make a stock solution.

[0223] Th was dissolved in water. The resulting solution (150 g) combined with Ex 1A (50 g) in an oil-jacketed sigma-blade mixer and stirred (50 rpm, 75°C, 400 mmHg) for 16 h to make Ex 1A.3.

[0224] Ex 1 A.4 was prepared by adapting the procedure for the preparation of Ex 1A.3.

[0225] Table 4.

[0226] Preparation of CaLac Stabilized CAB (Ex 1) Microparticles: Ex 1A.5

[0227] A slurry (50 g) was prepared by adding a 1 .2 wt% CaLac aqueous solution to Ex 1 A (41 .7 g). The slurry is then dried in an oil-jacketed sigma-blade mixer with stirring (50 rpm, 75°C, 400 mmHg) for 16 h.

[0228] Ex 1 A.6 was prepared by adapting the procedure for the preparation of Ex 1A.5. Table 5.

[0229] Additional Organic Salt Stabilized CAB Microparticles

[0230] Ex 1A.7(3wt% or 3000 ppm MgSuc), 1A.8(1.5wt% or 1500 ppm MgSuc), 1A.9 (1 ,5wt% or 1500 ppm NaSuc), and 1 A.10 (3wt% or 3000 ppm NaSuc) were prepared by adopting the procedure for the preparation of Ex 1 A.1 by adjusting the proportions of Ex 1 A and the various succinate salts.

[0231] Stabilizer Effect on the pH and Acids Formation

[0232] Cellulose esters are known to undergo hydrolytic degradation in an aqueous environment. The hydrolysis of the stabilized and un-stabilized CE particles (cellulose acetate butyrate, CAB) from Example 2 was monitored by determining the pH and the concentration of the acidic degradation products, namely acetic and butyric acid. The aqueous slurries containing 10% CE particles were made in 50 ml glass vials and placed in an oven at 50°C for accelerated aging. After one month, the vials were taken out to measure the pH of the slurry. The supernatant, obtained by separating the microparticles, was tested for acids. The presence of free acetic and butyric acid, formed through hydrolysis, was determined using an HPLC assay coupled with a UV detector. The impact of stabilizers on pH levels and the formation of acids is displayed in Table 6. Table 6. pH levels and the formation of acids.

[0233] During storage, the pH of the CAB slurries decreased due to the formation of free acids in the water phase. For the non-stabilized CAB sample, the pH dropped by more than 1 unit, going from an initial value of 4.35 to 3.29 at 50°C after one month. This decrease in pH indicates an increased fo rmation of acetic and butyric acids compared to the undoped CAB sample. Among the three stabilizers studied (magnesium succinate, sodium acetate, and calcium lactate), magnesium succinate was found to be the most effective in preventing hydrolysis. The pH of the CAB slurry doped with 1 wt% concentration of magnesium succinate dropped slightly from an initial value of 5.50 to 5.35. Additionally, the formation of acids was significantly lower compared to the undoped CAB sample and the CAB samples doped with the other two stabilizers.

Claims

CLAIMSWhat is claimed is:1 . A method, comprising:(i) applying an organic acid salt composition comprising an at least one organic acid salt to a cellulose ester particles composition comprising:(1 ) cellulose ester particles which comprise a cellulose ester, and(2) water, to produce a treated cellulose ester particles composition comprising:(1 ) treated cellulose ester particles,(2) at least one organic salt, and(3) water, wherein the cellulose ester particles and the treated cellulose ester particles have an average particle size of 50-500 microns; and(ii) subjecting the treated cellulose ester particles composition to a size reduction process to produce a stabilized cellulose ester microparticles composition comprising:(1 ) stabilized cellulose ester microparticles,(2) at least one organic acid salt, and(3) water, wherein the stabilized cellulose ester microparticles have an average particle size of from 1 -30 microns, and wherein the stabilized cellulose ester microparticles are biodegradable.

2. The method of claim 1 , wherein the organic acid salt composition is a solid, an aqueous suspension or an aqueous solution.

3. The method of claim 2, wherein the organic acid salt composition is the aqueous solution, and the applying is conducted by spraying the organic acid salt composition onto the cellulose ester particles in the cellulose ester particlescomposition or mixing the organic acid salt composition with the cellulose ester particles composition; or the applying is conducted by spraying the organic acid salt composition onto the cellulose ester particles composition.

4. The method of claim 3, wherein the organic acid salt composition is a solid or an aqueous suspension, and the applying is done by mixing the organic acid salt composition with the cellulose ester particles composition.

5. The method of any one of claims 1 -4, wherein the water in the cellulose ester particles composition is at least 1wt%, based on the total weigh of the cellulose ester particles composition and the organic acid salt composition is a solid.

6. The method of any one of claims 1 -5, wherein the method further comprises a step (iii) filtering the treated cellulose ester compositions; after the applying step (i) but before the subjecting step (ii).

7. The method of claim 6, wherein the method further comprises a step (iv) drying the treated cellulose ester composition; after the filtering step (iii), but before the subjecting step (ii).

8. The method of any one of claims 1 -7, wherein the size reduction process is a mechanical grinding process, or a milling process.

9. A method, comprising:(i) applying an organic acid salt composition comprising an at least one organic acid salt to a cellulose ester microparticles composition, comprising:(1 ) cellulose ester microparticles which comprise a cellulose ester, and(2) water,to produce a stabilized cellulose ester microparticles composition which comprises:(1 ) stabilized cellulose ester microparticles,(2) at least one organic acid salt, and(3) water, wherein the cellulose ester microparticles have an average particle size of from 1-30 microns, the stabilized cellulose ester microparticles have an average particle size of 1-30 microns, and the stabilized cellulose ester microparticles are biodegradable.

10. The method of claim 9, wherein the organic acid salt composition is a solid, an aqueous suspension or an aqueous solution.11 . The method of claim 10, wherein the organic acid salt composition is the aqueous solution, and the applying is conducted by:(i) spraying the organic acid salt composition onto the cellulose ester microparticles composition, or(ii) mixing the organic acid salt composition with the cellulose ester microparticles composition.

12. The method of claim 11 , wherein the organic acid salt composition is a solid or an aqueous suspension, and the applying is done by mixing the organic acid salt composition with the cellulose ester microparticles composition.

13. The method of any one of claims 11 -12, wherein the water in the cellulose ester microparticles composition is at least 1 wt% based on the total weight of the cellulose ester particles composition and the organic acid salt composition is a solid.

14. The method of any one of claims 11 -13, wherein the method further comprises a step (ii) drying the stabilized cellulose cellulose ester micropoarticles composition; which is performed after the applying step (i).

15. The method of any one of claims 11 -14, wherein the method further comprises a step (iii) filtering the stabilized cellulose ester microparticles composition, wherein the stabilized cellulose ester microparticles composition comprises a water content; which is performed after the applying step (i).

16. A composition, comprising:(i) cellulose ester particles, wherein the cellulose ester particles exhibit an average particle size of from 50 to 500 microns, wherein the cellulose ester particles comprise a cellulose ester;(ii) 0.1 to 2.0 wt% of an at least one organic acid salt, based on the total weight of the composition; and(iii) less than 10wt% of water, based on the total weight of the composition.

17. A composition, comprising:(i) cellulose ester microparticles, wherein the cellulose ester microparticles exhibit an average particle size of from 5 to 30 microns, wherein the cellulose ester microparticles comprise a cellulose ester;(ii) 0.1 to 2.0 wt% of an at least one organic acid salt, based on the total weight of the composition; and(iii) less than 10wt% of water, based on the total weight of the composition.

18. The composition of any one of claims 1 -17, wherein the composition is a personal care composition.

19. The method or composition of any one of claims 1 -18, wherein the at least one organic acid salt comprises an alkali metal cation or an alkaline metal cation.

20. The method or composition of claim 19, wherein the alkali metal cation is Li+, Na+, or K+, and the alkaline metal cation is Mg2+or Ca2+.21 . The method or composition of claim 20, wherein the organic acid component of the at least one organic acid salt is derived from a compound of formula I:wherein:G is a (Ci-8)alkylene, wherein the alkylene is unsubstituted or substituted by 1 to 2 hydroxyl substituents, a (Ci-8)alkenyl, or a phenyl; and n is 0, 1 , or 2.

22. The method or composition of any one of claims 1 -21 , wherein the compound of formula I is glutaric acid, pimelic acid, azelaic acid, sebacic acid, suberic acid, adipic acid, succinic acid, citric acid, tartaric acid, fumaric acid, terephthalic acid, isophthalic acid, acetic acid, or propionic acid, or lactic acid.

23. The method or composition of any one of claims 1 -22, wherein the organic acid salt is sodium succinate, potassium succinate, magnesium succinate, calcium succinate, sodium citrate, potassium citrate, magnesium citrate, calcium citrate, sodium acetate, potassium acetate, magnesium acetate, calcium acetate, sodium lactate, potassium lactate, magnesium lactate, or calcium lactate.

24. The method or composition of any one of claims 1 -23, wherein the cellulose ester is a cellulose acetate, a cellulose propionate, a cellulose butyrate, a cellulose acetate propionate, a cellulose acetate butyrate, or a combination thereof.

25. The method or composition of any one of claims 1 -24, wherein the cellulose ester has an average degree of substitution for hydroxyl substituents (“DSOH”) that is at least 0.5, or at least 0.6, or at least 0.7, or at least 0.8, or at least 0.9.

26. The method or composition of any one of claims 1 -25, wherein the cellulose ester microparticles further comprise a plasticizer.

27. The method or composition of any one of claims 1 -26, wherein the stabilized cellulose ester microparticles have: (i) a sphericity in the range of 30 to 100 percent, and (ii) a bulk density in the range of 0.2 to 0.7.

28. The composition of any one of claims 18-27, wherein the personal care composition is a foundation, a sunscreen, a lipstick, a mascara, an eye shadow, a lotion, a dry shampoo, a liquid shampoo, a body wash, a lotion, a hair conditioner, a skin moisturizer, a face wash, a tablet, a foot powder, a baby powder, a shaving cream, or a shaving gel.

29. The composition of claim 28, wherein the personal care composition is a loose powder, a compacted powder, a gel, an emulsion, a liquid, or an aerosol.

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