Cellulose acetate particles, cosmetic composition, and method for producing cellulose acetate particles

Abstract

SOLUTION: Cellulose acetate particles, wherein the cellulose acetate particles have a mean particle size of 80nm to 100 μm, a sphericity of 0.7 to 1.0, and a relative specific surface area of 3.0 to 20, and the cellulose acetate has a total degree of acetyl substitution of 0.7 to 3.0.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to cellulose acetate particles, a cosmetic composition using the same, and a method for producing the same. [Background technology]

[0002] Various polymeric microparticles have been proposed for various applications. For example, microparticles are contained in cosmetics, and the purposes of the microparticles contained in cosmetics are varied. The purposes of containing microparticles in cosmetics include improving the spreadability of the cosmetics, changing the texture, imparting a wrinkle-blurring effect, and improving the slipperiness of foundations and the like.

[0003] In particular, fine particles with high sphericity have an excellent tactile feel. To achieve an excellent tactile feel, fine particles to be incorporated into cosmetics must have a narrow particle size distribution and high sphericity. As such fine particles, fine particles made of synthetic polymers such as polyamides such as nylon 12, polymethyl methacrylate (PMMA), and polystyrene (PS) have been proposed.

[0004] Polyamide powder has also been used as a cosmetic base, particularly for makeup, because polymers such as polyamides have a refractive index similar to that of sweat, and when applied to the face, they can give the entire face a uniform glow and a lustrous appearance.

[0005] Generally, when kneading the various components of a cosmetic product with oil during the manufacturing process of a paste or semi-solid cosmetic product, the more oil the product contains, the easier it is to knead. However, if this oil remains in the finished cosmetic product in the same state as it was used during the manufacturing process, the face that has been made up will look greasy and the person wearing the makeup will feel sticky and uncomfortable.

[0006] Japanese Patent Laid-Open Publication No. 215638 / 1987 (Patent Document 1) states that "each particle of polyamide powder has a shape close to a perfect sphere, and its surface is smooth with almost no irregularities. Therefore, each particle itself has almost no adsorption capacity, and the absorption capacity of the powder as a whole is extremely low." To address this issue, the publication describes a method in which "a polyamide resin is heated and dissolved in a lower alcohol solvent containing an anhydrous alkaline earth metal chloride, and then slowly cooled" and a method in which "a polyamide resin having a total pore volume of 0.25 cc / g or more and a specific surface area of ​​4.0 m 2 / g or more and is spherical." However, the sphericity of this powder is insufficient and it cannot be said to be truly spherical.

[0007] Furthermore, in recent years, environmental issues, particularly the problem of microplastics in the ocean, have led to a trend toward using biodegradable resins. For example, Japanese Patent No. 6609726 (Patent Document 2) discloses cellulose acetate particles with high sphericity and describes a method for producing them as follows: "A method for producing cellulose acetate particles, comprising the steps of: mixing cellulose acetate having a total acetyl substitution degree of 0.7 to 2.9 with a plasticizer to obtain cellulose acetate impregnated with the plasticizer; kneading the cellulose acetate impregnated with the plasticizer and a water-soluble polymer at a temperature of 200°C to 280°C to obtain a dispersion containing the cellulose acetate impregnated with the plasticizer as a dispersoid; and removing the water-soluble polymer from the dispersion." However, this method does not produce porous cellulose acetate particles, and the particles lack sufficient oil absorption.

[0008] Attempts have also been made to obtain porous biodegradable particles. For example, Japanese Patent Laid-Open Publication No. 2015-214690 (Patent Document 3) describes aliphatic polyester resin particles with excellent oil absorption properties and suitable for applications such as additives for cosmetics and paints, and a method for producing the same. Specifically, it states that "the method for producing aliphatic polyester resin particles of the present invention is a method for producing polymer microparticles, characterized by dissolving and mixing (A) an aliphatic polyester resin, (B) a polymer different from the aliphatic polyester resin, and (C) an organic solvent containing a ketoester compound, forming an emulsion in a system that undergoes phase separation into two phases: a solution phase mainly composed of the aliphatic polyester resin (A) and a solution phase mainly composed of a polymer different from the aliphatic polyester resin (B), and then contacting the emulsion with a poor solvent for the aliphatic polyester resin (A), thereby precipitating the aliphatic polyester resin (A)." However, this manufacturing method is a method for producing fine particles using the so-called droplet method (emulsion polymerization), and the solid content during production is low, and volume shrinkage occurs after the target resin forms particles, resulting in particles with a low specific gravity and a shape that can hardly be described as perfect spheres, with internal voids, so that particles with sufficient biodegradability and tactile feel cannot be obtained.

[0009] Japanese Patent Laid-Open Publication No. 6-136175 (Patent Document 4) states, "According to the present invention, there is provided a method for producing spherical particles of cellulose diacetate, which comprises preparing A) a cellulose diacetate solution in which cellulose diacetate is dissolved in a mixed solvent of a chlorinated hydrocarbon and an alcohol, B) an alcoholic diluent of an alcohol or an ester and an alcohol, and C) an aqueous medium, mixing A) the cellulose diacetate solution with B) the alcoholic diluent to form a mixed solution, suspending this mixed solution in C) the aqueous medium to form droplets, and then evaporating and removing the chlorinated hydrocarbon in the droplets." However, such a production method using a suspension particle method does not produce particles with sufficient biodegradability and tactile feel.

[0010] Japanese Patent No. 4464815 (Patent Document 5) describes a method for producing particles made of the resin component (A), by melt-kneading a resin component (A) made of a thermoplastic resin with a water-soluble auxiliary component (B) containing a plasticizing component (B2) made of at least an oligosaccharide (B1) and a sugar alcohol to form a dispersion having a sea-island structure in which the continuous phase is made of the auxiliary component (B), and then eluting the auxiliary component (B) from this dispersion. However, this production method does not produce particles with sufficient biodegradability and tactile feel. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Japanese Patent Publication No. 62-215638 [Patent Document 2] Patent No. 6609726 [Patent Document 3] Japanese Patent Application Laid-Open No. 2015-214690 [Patent Document 4] Japanese Patent Application Publication No. 6-136175 [Patent Document 5] Patent No. 4464815 Summary of the Invention [Problem to be solved by the invention]

[0012] As described above, it has not been possible to produce particles having excellent tactile feel and oil absorbency using cellulose acetate, a material with excellent biodegradability. An object of the present disclosure is to provide fine particles having excellent biodegradability, tactile feel, and oil absorbency. [Means for solving the problem]

[0013] A first aspect of the present disclosure relates to cellulose acetate particles having an average particle diameter of 80 nm or more and 100 μm or less, a sphericity of 0.7 or more and 1.0 or less, and a relative specific surface area of ​​3.0 or more and 20 or less, and a total degree of acetyl substitution of the cellulose acetate of 0.7 or more and 3.0 or less.

[0014] The cellulose acetate particles may have a surface smoothness of 10% or more and 95% or less.

[0015] The cellulose acetate particles may have a bulk density of 0.2 or more and 0.7 or less.

[0016] The cellulose acetate particles may have an oil absorption using linseed oil of 60 ml or more per 100 g of the cellulose acetate particles.

[0017] In the cellulose acetate particles, the cellulose acetate may have a total degree of acetyl substitution of 1.6 or more and less than 2.9.

[0018] The cellulose acetate particles may have a relative specific surface area of ​​10 or more and 20 or less.

[0019] The cellulose acetate particles may contain a plasticizer, and the content of the plasticizer may be 2 parts by weight or more and 67 parts by weight or less relative to 100 parts by weight of the cellulose acetate.

[0020] In the cellulose acetate particles, the plasticizer may include at least one selected from the group consisting of citric acid-based plasticizers, glycerin ester-based plasticizers, and phthalic acid-based plasticizers.

[0021] A second aspect of the present disclosure relates to a cosmetic composition containing the cellulose acetate particles.

[0022] A third aspect of the present disclosure relates to a method for producing cellulose acetate particles, comprising the steps of: mixing cellulose acetate having a total degree of acetyl substitution of 0.7 to 3.0, a plasticizer, a first thermoplastic polymer, and a second thermoplastic polymer to obtain a cellulose acetate mixture containing the plasticizer, the first thermoplastic polymer, and the second thermoplastic polymer; melt-kneading the mixture at 200°C to 280°C; and removing the first thermoplastic polymer and the second thermoplastic polymer from the melt-kneaded mixture, wherein SPa, SPb, and SPc satisfy the following relationship: 0.1≦|SPc−SPa| / |SPb−SPa|≦0.9 where SPa is the SP value of the cellulose acetate, SPb is the SP value of the first thermoplastic polymer, and SPc is the SP value of the second thermoplastic polymer.

[0023] In the method for producing cellulose acetate particles, the mixing may be performed by mixing the cellulose acetate, the plasticizer, the first thermoplastic polymer, and the second thermoplastic polymer at a temperature of 20°C or higher but lower than 200°C, followed by melt-kneading.

[0024] In the method for producing cellulose acetate particles, the first thermoplastic polymer may be a water-soluble polymer.

[0025] In the method for producing cellulose acetate particles, the second thermoplastic polymer may be a water-soluble polymer.

[0026] In the method for producing cellulose acetate particles, the plasticizer may include at least one selected from the group consisting of citric acid-based plasticizers, glycerin ester-based plasticizers, adipic acid-based plasticizers, and phthalic acid-based plasticizers.

[0027] In the method for producing cellulose acetate particles, the plasticizer may include at least one selected from the group consisting of triethyl citrate, acetyltriethyl citrate, acetyltributyl citrate, triacetin, diacetin, diisononyl adipate, and diethyl phthalate.

[0028] In the method for producing cellulose acetate particles, the plasticizer may include at least one selected from the group consisting of acetyltriethyl citrate, triacetin, diacetin, and diethyl phthalate.

[0029] In the method for producing cellulose acetate particles, the plasticizer may include at least one selected from the group consisting of acetyltriethyl citrate and triacetin.

[0030] In the method for producing cellulose acetate particles, the first thermoplastic polymer may include at least one selected from the group consisting of polyvinyl alcohol and thermoplastic starch.

[0031] In the method for producing cellulose acetate particles, the second thermoplastic polymer may be polyethylene glycol. [Effects of the Invention]

[0032] According to the present disclosure, it is possible to provide fine particles that are excellent in biodegradability, texture, and oil absorbency. [Brief explanation of the drawings]

[0033] [Figure 1] FIG. 1 is a scanning electron microscope (SEM) image (magnification: 3000 times) of the cellulose acetate particles of Example A-1. [Figure 2] FIG. 2 is an SEM image (magnification: 5000 times) of the cellulose acetate particles of Example A-1. [Figure 3] FIG. 3 is an SEM image (magnification: 6000 times) of the cellulose acetate particles of Example A-1, and is a drawing for explaining the method for evaluating the surface smoothness (%). [Figure 4] FIG. 4 is a binarized image of FIG. 3, and is a diagram for explaining the method for evaluating the surface smoothness (%). [Figure 5]FIG. 5 is an SEM image (magnification: 3000 times) of the cellulose acetate particles of Example A-12. [Figure 6] FIG. 6 is an SEM image (magnification: 5000 times) of the cellulose acetate particles of Example A-12. [Figure 7] FIG. 7 is an SEM image (magnification: 3000 times) of the cellulose acetate particles of Comparative Example A-1. [Figure 8] FIG. 8 is an SEM image (magnification: 5000 times) of the cellulose acetate particles of Comparative Example A-1. DETAILED DESCRIPTION OF THE INVENTION

[0034] [Cellulose acetate particles] The cellulose acetate particles of the present disclosure are cellulose acetate particles having an average particle diameter of 80 nm or more and 100 μm or less, a sphericity of 0.7 or more and 1.0 or less, and a relative specific surface area of ​​3.0 or more and 20 or less, and a total acetyl substitution degree of the cellulose acetate of 0.7 or more and 3.0 or less.

[0035] The average particle size of the cellulose acetate particles of the present disclosure is 80 nm or more and 100 μm or less, and the average particle size may be 100 nm or more, 1 μm or more, 2 μm or more, or 4 μm or more. It may also be 80 μm or less, 40 μm or less, 20 μm or less, or 14 μm or less. If the average particle size is too large, the feel is poor. If the average particle size is too small, production becomes difficult. The feel includes the feel on the skin when the cellulose acetate particles are directly touched, as well as the feel when the particles are incorporated into a cosmetic composition, for example.

[0036] The average particle size can be measured using dynamic light scattering. The average particle size (nm, μm, etc.) here refers to the particle size value corresponding to 50% of the integrated scattering intensity in this particle size distribution.

[0037] The particle size variation coefficient of the cellulose acetate particles of the present disclosure may be 0% or more and 60% or less, or may be 2% or more and 50% or less.

[0038] The particle size variation coefficient (%) can be calculated by dividing the standard deviation of particle sizes by the average particle size x 100.

[0039] The sphericity of the cellulose acetate particles of the present disclosure is 0.7 or more and 1.0 or less, preferably 0.8 or more and 1.0 or less, and more preferably 0.9 or more and 1.0 or less. If the sphericity is less than 0.7, the sphericity will be inferior in texture, and for example, when incorporated into a cosmetic composition, the texture will be poor.

[0040] Sphericity can be measured by the following method. The sphericity is the average value of the minor axis / major axis ratio of each particle obtained from images of the particles observed with a scanning electron microscope (SEM). The closer the sphericity is to 1, the more truly spherical the particle is.

[0041] The relative specific surface area (hereinafter sometimes referred to as RSSA) of the cellulose acetate particles of the present disclosure is 3.0 or more and 20 or less. The relative specific surface area is preferably 5.0 or more, more preferably 7.0 or more, even more preferably 8.5 or more, even more preferably 9.0 or more, and particularly preferably 10 or more. The relative specific surface area may be 18 or less. If it is less than 3.0, the particles will be spherical with a smooth surface and will have few or no pores, which will be difficult to deform under applied external forces and will have poor tactile feel (particularly softness). If it exceeds 20, it will be difficult for the particles to maintain high sphericity, resulting in poor tactile feel.

[0042] The relative specific surface area (RSSA) is defined by the following formula: RSSA = measured specific surface area / theoretical specific surface area

[0043] The theoretical specific surface area is the specific surface area calculated from the measurement results of particle size distribution, assuming that the particles are spherical fine particles with smooth surfaces, and is defined as follows: Theoretical specific surface area = (1 / d)Σ(Pι*Sι / Vι) d: True specific gravity (1350 (kg / m 3 ) is constant) Pι: Distribution (volume fraction) Sι: Surface area of ​​one cellulose acetate particle (m 2 ), that is, the surface area of ​​a spherical cellulose acetate particle with a diameter of Lι (m) is (4 / 3)*π*(Lι / 2) 3 V: Volume of one cellulose acetate particle (m 3 ), that is, the volume of a spherical cellulose acetate particle with a diameter of Lι (m) is 4π*(Lι / 2) 2

[0044] The specific surface area is determined by the nitrogen BET specific surface area measurement method.

[0045] The surface smoothness of the cellulose acetate particles of the present disclosure is preferably 10% to 95%, more preferably 50% to 92%, and even more preferably 75% to 90%. Too low a surface smoothness means that the proportion of concave portions (pore portions) in the particles is too high. If the surface smoothness is too low, it becomes difficult to form a spherical shape, and the sphericity may not satisfy 0.7 or more. If the sphericity is less than 0.7, the effects of the present disclosure cannot be achieved. In particular, the tactile feel is extremely poor. On the other hand, too high a surface smoothness means that the proportion of pore portions in the particles is too low or nonexistent, making the particles difficult to deform under applied external forces, resulting in poor tactile feel (particularly softness), and insufficient oil absorption.

[0046] The surface smoothness can be determined by taking a scanning electron microscope photograph of the particles, observing the irregularities on the particle surface, and determining the area of ​​the depressions.

[0047] The cellulose acetate of the cellulose acetate particles of the present disclosure has a total degree of acetyl substitution of 0.7 or more and 3.0 or less, preferably 0.7 or more and less than 2.9, more preferably 1.0 or more and less than 2.9, even more preferably 1.4 or more and less than 2.9, particularly preferably 1.8 or more and less than 2.9, and most preferably 1.6 or more and less than 2.9.

[0048] If the total degree of acetyl substitution is less than 0.7, the water solubility becomes high, and in the step of removing the first thermoplastic polymer and the second thermoplastic polymer from the mixture in the production of cellulose acetate particles described below, the cellulose acetate is likely to be eluted, which may reduce the sphericity of the resulting particles and result in an inferior feel to the touch.

[0049] The total acetyl substitution degree of cellulose acetate can be measured by the following method. First, the total acetyl substitution degree is the sum of the acetyl substitution degrees at the 2-, 3-, and 6-positions of the glucose ring of cellulose acetate, and the acetyl substitution degrees at the 2-, 3-, and 6-positions of the glucose ring of cellulose acetate particles can be measured by NMR according to the method of Tezuka (Tezuka, Carbonydr. Res. 273, 83 (1995)). That is, the free hydroxyl groups of a cellulose acetate sample are propionylated with propionic anhydride in pyridine. The obtained sample is dissolved in deuterated chloroform, and 13 The C-NMR spectrum is measured. The carbon signals of the acetyl group appear in the region from 169 ppm to 171 ppm in the order of 2, 3, and 6 positions from the high magnetic field, and the signals of the carbonyl carbon of the propionyl group appear in the same order in the region from 172 ppm to 174 ppm. From the abundance ratio of the acetyl group and the propionyl group at each corresponding position, the degree of acetyl substitution at the 2, 3, and 6 positions of the glucose ring in the original cellulose acetate can be calculated. The degree of acetyl substitution is 13 In addition to C-NMR, 1 It can also be analyzed by H-NMR.

[0050] Furthermore, the total degree of acetyl substitution can be determined by converting the degree of acetylation determined according to the method for measuring the degree of acetylation in ASTM: D-817-91 (test methods for cellulose acetate, etc.) using the following formula. This is the most common method for determining the degree of substitution for cellulose acetate. DS=162.14×AV×0.01 / (60.052-42.037×AV×0.01) In the above formula, DS is the total degree of acetyl substitution, and AV is the degree of acetylation (%). Note that the value of the degree of substitution obtained by conversion usually has a slight error between it and the NMR measurement value. If the converted value differs from the NMR measurement value, the NMR measurement value is used. Furthermore, if the value differs depending on the specific method of NMR measurement, the NMR measurement value obtained by Tezuka's method is used.

[0051] The method for measuring the acetylation degree in ASTM D-817-91 (Test Methods for Cellulose Acetate, etc.) is outlined below. First, 1.9 g of dried cellulose acetate is weighed out and dissolved in 150 mL of a mixed solution of acetone and dimethyl sulfoxide (volume ratio 4:1). 30 mL of 1N aqueous sodium hydroxide is added, and the solution is saponified at 25°C for 2 hours. Phenolphthalein is added as an indicator, and excess sodium hydroxide is titrated with 1N sulfuric acid (concentration factor: F). A blank test is also conducted in the same manner as above, and the acetylation degree is calculated according to the following formula. Average acetylation rate (%) = {6.5 × (BA) × F} / W (In the formula, A is the titer (mL) of 1N sulfuric acid for the sample, B is the titer (mL) of 1N sulfuric acid for the blank test, F is the concentration factor of 1N sulfuric acid, and W is the weight of the sample.)

[0052] The cellulose acetate particles of the present disclosure may have a bulk density of 0.1 or more and 0.9 or less, 0.2 or more and 0.9 or less, or 0.2 or more and 0.7 or less. For example, when the particles are incorporated into a cosmetic product, the higher the bulk density of the particles, the better the fluidity of the cosmetic product. The bulk density can be measured by a method in accordance with JIS K 1201-1.

[0053] The oil absorption of the cellulose acetate particles of the present disclosure using linseed oil is preferably 60 ml or more per 100 g of cellulose acetate particles, more preferably 70 ml or more, and even more preferably 80 ml or more. The oil absorption may be 200 ml or less, preferably 100 ml or less, and more preferably 90 ml or less. When the oil absorption is 60 ml or more per 100 g of cellulose acetate particles, the cellulose acetate particles have a particularly excellent feel to the touch, and when incorporated into a cosmetic composition, for example, the feel on the skin is further improved. When the oil absorption is more than 200 ml per 100 g of cellulose acetate particles, the cellulose acetate particles may absorb more oil than necessary from the skin when used in a cosmetic composition, causing dryness. From the viewpoint of preventing excessive dryness and obtaining a cosmetic composition that feels good on the skin, the oil absorption may be 60 ml to 200 ml, 60 ml to 100 ml, 60 ml to 90 ml, 70 ml to 200 ml, 70 ml to 100 ml, 70 ml to 90 ml, 80 ml to 200 ml, 80 ml to 100 ml, or 80 ml to 90 ml per 100 g of cellulose acetate particles.

[0054] The oil absorption using linseed oil can be determined according to JIS K5101-13-1:2004 (ISO 787-5:1980) Pigment Test Methods - Part 13: Oil Absorption - Section 1: Refined Linseed Oil Method.

[0055] The cellulose acetate particles of the present disclosure may or may not contain a plasticizer. In the present disclosure, a plasticizer refers to a compound that can increase the plasticity of cellulose acetate. The plasticizer is not particularly limited, and examples thereof include adipic acid-based plasticizers including adipic acid esters such as dimethyl adipate, dibutyl adipate, diisostearyl adipate, diisodecyl adipate, diisononyl adipate, diisobutyl adipate, diisopropyl adipate, diethylhexyl adipate, dioctyl adipate, dioctyldodecyl adipate, dicapryl adipate, and dihexyldecyl adipate; citric acid-based plasticizers including citric acid esters such as acetyltriethyl citrate, acetyltributyl citrate, isodecyl citrate, isopropyl citrate, triethyl citrate, triethylhexyl citrate, and tributyl citrate; glutaric acid-based plasticizers including glutaric acid esters such as diisobutyl glutarate, dioctyl glutarate, and dimethyl glutarate; diisobutyl succinate, succinic acid-based plasticizers including glutaric acid esters such as diisobutyl glutarate, dioctyl glutarate, and dimethyl glutarate; Examples of suitable plasticizers include succinic acid plasticizers including succinic acid esters such as diethyl sebacate, diethylhexyl succinate, and dioctyl succinate; sebacic acid plasticizers including sebacate esters such as diisoamyl sebacate, diisooctyl sebacate, diisopropyl sebacate, diethyl sebacate, diethylhexyl sebacate, and dioctyl sebacate; glycerin ester plasticizers including glycerin alkyl esters such as triacetin, diacetin, and monoacetin; neopentyl glycol; phthalic acid plasticizers including phthalic acid esters such as ethyl phthalate, methyl phthalate, diaryl phthalate, diethyl phthalate, diethylhexyl phthalate, dioctyl phthalate, dibutyl phthalate, and dimethyl phthalate; and phosphate plasticizers including phosphate esters such as trioleyl phosphate, tristearyl phosphate, and tricetyl phosphate. Other examples include di-2-methoxyethyl phthalate, dibutyl tartrate, ethyl o-benzoylbenzoate, ethyl phthalyl ethyl glycolate (EPEG), methyl phthalyl ethyl glycolate (MPEG), N-ethyltoluenesulfonamide, p-toluenesulfonic acid, triethyl o-cresyl phosphate (TEP), triphenyl phosphate (TPP), and tributarybionin.These plasticizers may be used alone or in combination of two or more.

[0056] Among these, it is preferable to include at least one selected from the group consisting of citric acid plasticizers including citrate esters such as triethyl citrate, acetyl triethyl citrate, and acetyl tributyl citrate; glycerin ester plasticizers including glycerin alkyl esters such as triacetin, diacetin, and monoacetin; and phthalic acid plasticizers such as ethyl phthalate and methyl phthalate, more preferably at least one selected from the group consisting of triethyl citrate, acetyl triethyl citrate, acetyl tributyl citrate, triacetin, diacetin, diisononyl adipate, and diethyl phthalate, even more preferably at least one selected from the group consisting of acetyl triethyl citrate, triacetin, diacetin, and diethyl phthalate, and particularly preferably at least one selected from the group consisting of acetyl triethyl citrate and triacetin. However, phthalic acid plasticizers should be used with caution due to concerns about their similarity to endocrine disrupters.

[0057] When the cellulose acetate particles contain a plasticizer, the content of the plasticizer in the cellulose acetate particles is not particularly limited. For example, it may be more than 0 part by weight and not more than 67 parts by weight, 2 parts by weight or more and not more than 67 parts by weight, 11 parts by weight or more and not more than 43 parts by weight, or 18 parts by weight or more and not more than 25 parts by weight, relative to 100 parts by weight of cellulose acetate.

[0058] The content of the plasticizer in the cellulose acetate particles is 1 It is determined by H-NMR measurement.

[0059] The cellulose acetate particles of the present disclosure are highly biodegradable, with a biodegradation rate of preferably 40% by weight or more, more preferably 50% by weight or more, and even more preferably 60% by weight or more within 30 days.

[0060] The biodegradation rate can be measured by a method using activated sludge in accordance with JIS K6950.

[0061] The cellulose acetate particles of the present disclosure can be produced by the production method described below.

[0062] The cellulose acetate particles of the present disclosure have excellent biodegradability, texture, and oil absorption properties, and therefore can be suitably used, for example, in cosmetic compositions. When incorporated into a cosmetic composition, the cellulose acetate particles of the present disclosure have a high oil absorption capacity, and therefore can absorb sebum and prevent makeup from smearing. Furthermore, the cellulose acetate particles of the present disclosure have high sphericity, are easily deformed by applied external forces, and are excellent in softness, thereby improving the texture of the cosmetic composition. Furthermore, the cellulose acetate particles of the present disclosure have pores, and therefore functional drugs and the like can be easily loaded into the pores, making them suitable for use as functional particles.

[0063] Cosmetic compositions include foundations such as liquid foundations and powder foundations; concealers; sunscreens; makeup bases; lipsticks and lipstick bases; face powders such as body powders, pressed face powders, and face powders; pressed powder eye shadows; wrinkle-concealing creams; and topical skin and hair preparations primarily intended for cosmetic purposes, such as skin care lotions, and are not limited in their formulation. Formulations may include liquids such as aqueous solutions, emulsions, and suspensions; semisolids such as gels and creams; and solids such as powders, granules, and solids. Formulations may also include emulsions such as creams and emulsions; oil gels such as lipsticks; powders such as foundations; and aerosols such as hair styling products.

[0064] [Method for producing cellulose acetate particles] The method for producing cellulose acetate particles according to the present disclosure is as follows: The method comprises the steps of: mixing cellulose acetate having a total degree of acetyl substitution of 0.7 to 3.0, a plasticizer, a first thermoplastic polymer, and a second thermoplastic polymer to obtain a cellulose acetate mixture containing the plasticizer, the first thermoplastic polymer, and the second thermoplastic polymer; melt-kneading the mixture at 200°C to 280°C; and removing the first thermoplastic polymer and the second thermoplastic polymer from the melt-kneaded mixture; wherein SPa, SPb, and SPc satisfy the following relationship, where SPa is the SP value of the cellulose acetate, SPb is the SP value of the first thermoplastic polymer, and SPc is the SP value of the second thermoplastic polymer: 0.1≦|SPc-SPa| / |SPb-SPa|≦0.9

[0065] (Step of Obtaining a Cellulose Acetate Mixture) In the step of obtaining a mixture of cellulose acetate containing the plasticizer, the first thermoplastic polymer, and the second thermoplastic polymer, cellulose acetate having a total acetyl substitution degree of 0.7 or more and 3.0 or less, the plasticizer, the first thermoplastic polymer, and the second thermoplastic polymer are mixed.

[0066] Cellulose acetate having a total degree of acetyl substitution of 0.7 to 3.0 can be produced by known methods for producing cellulose acetate. Examples of such production methods include the so-called acetic acid method, which uses acetic anhydride as the acetylating agent, acetic acid as the diluent, and sulfuric acid as the catalyst. The basic steps of the acetic acid method are: (1) a pretreatment step in which a pulp raw material (dissolving pulp) with a relatively high α-cellulose content is disintegrated and crushed, and then acetic acid is sprayed and mixed with the pulp; (2) an acetylation step in which the pretreated pulp from (1) is reacted with a mixed acid consisting of acetic anhydride, acetic acid, and an acetylation catalyst (e.g., sulfuric acid); (3) an aging step in which cellulose acetate is hydrolyzed to cellulose acetate with the desired acetylation degree; and (4) a posttreatment step in which the cellulose acetate after the hydrolysis reaction is precipitated from the reaction solution, purified, stabilized, and dried.

[0067] The total degree of acetyl substitution of the cellulose acetate is 0.7 or more and 3.0 or less, preferably 0.7 or more and less than 2.9, more preferably 1.0 or more and less than 2.9, even more preferably 1.4 or more and less than 2.9, particularly preferably 1.8 or more and less than 2.9, and most preferably 1.6 or more and less than 2.9. The total degree of acetyl substitution can be adjusted by adjusting the conditions of the aging step (conditions such as time and temperature).

[0068] Any plasticizer can be used without particular limitation as long as it has a plasticizing effect in the melt extrusion processing of cellulose acetate. Specifically, the above-mentioned plasticizers exemplified as plasticizers contained in cellulose acetate particles can be used alone or in combination of two or more.

[0069] Among the above-mentioned plasticizers, it is preferable to include at least one selected from the group consisting of citric acid-based plasticizers including citric acid esters such as triethyl citrate, acetyltriethyl citrate, and acetyltributyl citrate; glycerin ester-based plasticizers including glycerin alkyl esters such as triacetin, diacetin, and monoacetin; adipic acid-based plasticizers such as diisononyl adipate; and phthalic acid-based plasticizers such as ethyl phthalate and methyl phthalate. It is more preferable to include at least one selected from the group consisting of triethyl citrate, acetyltriethyl citrate, acetyltributyl citrate, triacetin, diacetin, diisononyl adipate, and diethyl phthalate. It is even more preferable to include at least one selected from the group consisting of acetyltriethyl citrate, triacetin, diacetin, and diethyl phthalate. It is particularly preferable to include at least one selected from the group consisting of acetyltriethyl citrate and triacetin. However, caution is required when using phthalate plasticizers as there are concerns about their similarity to environmental hormones.

[0070] The amount of plasticizer may be more than 0 part by weight and not more than 67 parts by weight, 2 parts by weight or more and not more than 67 parts by weight, 11 parts by weight or more and not more than 43 parts by weight, or 18 parts by weight or more and not more than 25 parts by weight, relative to 100 parts by weight of cellulose acetate. If the amount is too small, the sphericity of the resulting cellulose acetate particles tends to decrease, while if the amount is too large, the particle shape cannot be maintained, and the sphericity tends to decrease.

[0071] The first thermoplastic polymer and the second thermoplastic polymer can be used without any particular limitation as long as they satisfy the following relational expressions.

[0072] When the SP value of the cellulose acetate is SPa, the SP value of the first thermoplastic polymer is SPb, and the SP value of the second thermoplastic polymer is SPc, SPa, SPb, and SPc satisfy the following formula. 0.1≦|SPc-SPa| / |SPb-SPa|≦0.9

[0073] The thermoplastic polymer in this specification is not particularly limited as long as it is a polymer that has broad thermoplasticity. It is preferable that both the first thermoplastic polymer and the second thermoplastic polymer are water-soluble, in other words, they are water-soluble polymers. Here, water-soluble means that when 1 g of the polymer is dissolved in 100 g of water at 25°C, the insoluble content is less than 50 wt%. Furthermore, a "polymer" is defined as a compound having a structure formed by repeatedly bonding one or more types of structural units. In this specification, a compound with a weight-average molecular weight of 10,000 or more is referred to as a "polymer."

[0074] Examples of the first thermoplastic polymer or the second thermoplastic polymer include polyvinyl alcohol, polyethylene glycol, sodium polyacrylate, polyvinylpyrrolidone, polypropylene oxide, polyglycerin, polyethylene oxide, polyvinyl acetate, modified starch, thermoplastic starch, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose. Thermoplastic starch can be obtained by known methods. For example, see JP-B-6-6307 and WO92 / 04408. More specifically, for example, tapioca starch mixed with approximately 20% glycerin as a plasticizer and kneaded in a twin-screw extruder can be used.

[0075] The first thermoplastic polymer preferably includes at least one selected from the group consisting of polyvinyl alcohol, sodium polyacrylate, polyvinylpyrrolidone, and thermoplastic starch, and more preferably includes at least one selected from the group consisting of polyvinyl alcohol and thermoplastic starch. The weight-average molecular weight of the polyvinyl alcohol is preferably 500 to 50,000.

[0076] The second thermoplastic polymer may be one that satisfies the relationship 0.1≦|SPc−SPa| / |SPb−SPa|≦0.9. Preferably, it satisfies the relationship 0.2<|SPc−SPa| / |SPb−SPa|<0.8. If this value is |SPc−SPa| / |SPb−SPa|<0.1 or |SPc−SPa| / |SPb−SPa|>0.9, the pores formed in the resulting cellulose acetate particles will be small and the number of pores will be reduced, resulting in a lower relative specific surface area (RSSA) and an inferior feel to the touch, which is undesirable.

[0077] The second thermoplastic polymer is preferably polyethylene glycol.

[0078] When polyvinyl alcohol, thermoplastic starch, or modified starch is used as the first thermoplastic polymer, it is particularly preferred to use polyethylene glycol as the second thermoplastic polymer. This is because polyvinyl alcohol, thermoplastic starch, modified starch, and polyethylene glycol are all water-soluble and thermoplastic. The weight-average molecular weight of the polyethylene glycol is preferably 500 or more and 50,000 or less.

[0079] Here, the weight average molecular weight (Mw) is a value obtained by multiplying each molecule by its molecular weight to obtain a weighted average, and is determined by gel permeation chromatography (GPC).

[0080] The amount of the first thermoplastic polymer is preferably 110 to 15,000 parts by weight, more preferably 180 to 1,200 parts by weight, and even more preferably 200 to 800 parts by weight, per 100 parts by weight of cellulose acetate. If the amount is less than 110 parts by weight, the sphericity may be poor and irregular shaped cellulose acetate particles may be produced, whereas if the amount exceeds 15,000 parts by weight, the particle size of the resulting cellulose acetate particles may be too small.

[0081] The amount of the second thermoplastic polymer is preferably 1 to 1500 parts by weight, more preferably 2 to 150 parts by weight, and even more preferably 3 to 100 parts by weight, per 100 parts by weight of cellulose acetate. If the amount is less than 1 part by weight, sufficient pores may not be formed in the resulting cellulose acetate particles, resulting in insufficient oil absorption.

[0082] The mixing of cellulose acetate and a plasticizer, or the mixing of cellulose acetate, a plasticizer, a first thermoplastic polymer, and a second thermoplastic polymer, can be carried out by a dry method or a wet method using a mixer such as a Henschel mixer. When a mixer such as a Henschel mixer is used, the temperature inside the mixer may be set to a temperature at which the cellulose acetate does not melt, for example, in the range of 20°C or higher and lower than 200°C.

[0083] Furthermore, the mixing of cellulose acetate and the plasticizer, or the mixing of cellulose acetate, the plasticizer, the first thermoplastic polymer, and the second thermoplastic polymer, may be carried out by melt kneading. The melt kneading may be carried out in combination with mixing using a mixer such as a Henschel mixer. In this case, it is preferable to mix using a mixer such as a Henschel mixer at a temperature of 20°C or higher but lower than 200°C, and then perform melt kneading. The plasticizer and cellulose acetate, or the plasticizer, the first thermoplastic polymer, the second thermoplastic polymer, and cellulose acetate, are more uniformly mixed in a shorter time, resulting in higher sphericity of the cellulose acetate particles that can be finally prepared, and improved tactile feel and comfort.

[0084] The melt-kneading is preferably carried out by heating and mixing in an extruder. The kneading temperature (cylinder temperature) of the extruder may be in the range of 200°C to 230°C. Even at temperatures in this range, plasticization can be achieved to obtain a uniform kneaded product. If the temperature is too low, the sphericity of the resulting particles will decrease, resulting in a poor feel and texture. If the temperature is too high, the kneaded product may be altered or discolored due to heat. In addition, the viscosity of the molten product may decrease, potentially resulting in insufficient kneading of the resin in the twin-screw extruder.

[0085] The melting point of cellulose acetate is approximately 230°C to 280°C, depending on the degree of substitution. This is close to the decomposition temperature of cellulose acetate, so melt-kneading is usually difficult within this temperature range. However, cellulose acetate (flakes) impregnated with a plasticizer can have a lower plasticization temperature. The kneading temperature (cylinder temperature) may be 200°C, for example, when using a twin-screw extruder. The kneaded material may be extruded into strands and then formed into pellets by hot cutting or the like. In this case, the die temperature may be around 220°C.

[0086] (Step of melt-kneading the cellulose acetate mixture) In this step, the mixture is melt-kneaded at a temperature of 200°C or higher and 280°C or lower.

[0087] The mixture can be kneaded using an extruder such as a twin-screw extruder, etc. The kneading temperature refers to the cylinder temperature.

[0088] The cellulose acetate mixture may be extruded in the form of a string from a die attached to the tip of an extruder such as a twin-screw extruder, and then cut into pellets. In this case, the die temperature may be 220°C or higher and 300°C or lower.

[0089] (Step of Removing the First Thermoplastic Polymer and the Second Thermoplastic Polymer) The step of removing the first thermoplastic polymer and the second thermoplastic polymer from the melt-kneaded mixture will now be described.

[0090] The method for removing the first thermoplastic polymer and the second thermoplastic polymer is not particularly limited as long as the first thermoplastic polymer and the second thermoplastic polymer can be removed from the melt-kneaded mixture by dissolution or the like, and examples thereof include a method of dissolving and removing the first thermoplastic polymer and the second thermoplastic polymer in the mixture using a solvent such as water; an alcohol such as methanol, ethanol, isopropanol, or a mixed solution thereof. Specifically, for example, a method of removing the first thermoplastic polymer and the second thermoplastic polymer from the mixture by mixing the mixture with the solvent, filtering, and collecting the residue can be mentioned.

[0091] In the step of removing the first thermoplastic polymer and the second thermoplastic polymer from the mixture, the plasticizer may or may not be removed from the mixture together with the first thermoplastic polymer and the second thermoplastic polymer, and therefore the resulting cellulose acetate particles may or may not contain a plasticizer.

[0092] The mixing ratio of the mixture to the solvent is preferably 0.01% by weight to 20% by weight, more preferably 2% by weight to 15% by weight, and even more preferably 4% by weight to 13% by weight, based on the total weight of the mixture and the solvent. If the mixture ratio is higher than 20% by weight, the first thermoplastic polymer and the second thermoplastic polymer may not be sufficiently dissolved, making them impossible to remove by washing, or it may be difficult to separate the cellulose acetate particles that are not dissolved in the solvent from the first thermoplastic polymer and the second thermoplastic polymer that are dissolved in the solvent by filtration, centrifugation, or other procedures.

[0093] The temperature at which the mixture and the solvent are mixed is preferably from 0° C. to 200° C., more preferably from 20° C. to 110° C., and even more preferably from 40° C. to 80° C. At temperatures below 0° C., the first thermoplastic polymer and the second thermoplastic polymer may not be sufficiently dissolved, making them difficult to remove by washing, whereas at temperatures above 200° C., deformation or aggregation of the particles may occur, making it difficult to remove the particles while maintaining the desired particle shape.

[0094] The time for mixing the mixture with the solvent is not particularly limited and may be adjusted as appropriate, but may be, for example, 0.5 hours or more, 1 hour or more, 3 hours or more, 5 hours or more, or 6 hours or less.

[0095] Furthermore, the mixing method is not limited as long as it can dissolve the first thermoplastic polymer and the second thermoplastic polymer. For example, by using a stirring device such as an ultrasonic homogenizer or a three-one motor, the first thermoplastic polymer and the second thermoplastic polymer can be efficiently removed from the mixture even at room temperature.

[0096] For example, when a three-one motor is used as the stirring device, the rotation speed during mixing of the mixture and the solvent may be, for example, 5 rpm or more and 3000 rpm or less. This allows the first thermoplastic polymer and the second thermoplastic polymer to be removed from the mixture more efficiently. This also allows the plasticizer to be removed efficiently from the mixture.

[0097] Each feature disclosed herein may be combined with any other feature disclosed herein. [Example]

[0098] The present disclosure will be specifically described below using examples, but the technical scope of the present disclosure is not limited to these examples. Each configuration and combination thereof in each embodiment is merely an example, and addition, omission, substitution, and other modifications of the configuration are possible as appropriate within the scope of the gist of the present disclosure.

[0099] (Example A-1) Cellulose diacetate (manufactured by Daicel Corporation, total acetyl substitution degree DS = 2.4, SP value: 24 (MPa 1 / 2 100 parts by weight of cellulose acetate and 25 parts by weight of triacetin as a plasticizer were dry-blended, dried at 80°C for 12 hours or more, and then stirred and mixed using a Henschel mixer to obtain a mixture of cellulose acetate and the plasticizer. The resulting mixture was fed into a twin-screw extruder (PCM30 manufactured by Ikegai Corporation, cylinder temperature: 200°C, die temperature: 220°C), melt-kneaded, extruded, and pelletized to obtain a kneaded product.

[0100] 100 parts by weight of pellets of the obtained kneaded product and polyvinyl alcohol (PVA, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.; melting point: 190°C, saponification degree: 99.1%, SP value: 34 (MPa)) as a first thermoplastic polymer were mixed. 1 / 2 )) as a second thermoplastic polymer, and 271 parts by weight of polyethylene glycol (PEG, SP value: 20 (MPa 1 / 2)) 21 parts by weight were blended in a dry state, and then fed into a twin-screw extruder (PCM30 manufactured by Ikegai Corporation, cylinder temperature 220°C, die temperature 220°C) and extruded to form a cellulose acetate mixture.

[0101] The resulting cellulose acetate mixture was mixed with pure water (solvent) so that the mixture was 5% by weight or less (weight of the mixture / (weight of the mixture + weight of pure water) × 100), and stirred for 3 hours at 80°C and 100 rpm using a Three-One Motor (BL-3000, manufactured by Shinto Scientific Co., Ltd.). The stirred solution was filtered through filter paper (No. 5A, manufactured by ADVANTEC), and the filtered material was removed. The removed filtered material was again adjusted with pure water so that the mixture was 5% by weight or less, and further stirred at 80°C and 100 rpm for 3 hours, filtered, and the filtered material was removed. This process was repeated three or more times to obtain cellulose acetate particles.

[0102] The average particle size, particle size variation coefficient, sphericity, oil absorption, surface smoothness, bulk specific gravity, and RSSA of the obtained cellulose acetate particles were measured, and their biodegradability and tactile feel were evaluated. The results are shown in Table 1. The average particle size, particle size variation coefficient, sphericity, oil absorption, surface smoothness, bulk specific gravity, RSSA, biodegradability, and tactile feel were measured or evaluated using the following methods. Scanning electron microscope (SEM) images are shown in Figure 1-3. The scale bars in Figure 1-3 are 30 μm for the SEM images at 3000x magnification, 20 μm for the SEM images at 5000x magnification, and 5.00 μm for the SEM images at 6000x magnification.

[0103] <Average particle size and particle size variation coefficient> The average particle size was measured using dynamic light scattering. First, the sample was adjusted to a concentration of approximately 100 ppm using pure water and then suspended in pure water using an ultrasonic vibration device. The volume frequency particle size distribution was then determined using laser diffraction (HORIBA, Ltd., "Laser Diffraction / Scattering Particle Size Distribution Analyzer LA-960" using 15 minutes of ultrasonic treatment, refractive index (1.500), medium (water; 1.333)), and the average particle size was measured. The average particle size (nm, μm, etc.) referred to here was the particle size value corresponding to 50% of the cumulative scattering intensity in the volume frequency particle size distribution. The particle size variation coefficient (%) was calculated by dividing the standard deviation of the particle size by the average particle size x 100.

[0104] <Sphericity> Using particle images observed with a scanning electron microscope (SEM), the major and minor axes of 30 randomly selected particles were measured, the minor axis / major axis ratio of each particle was calculated, and the average value of the minor axis / major axis ratio was taken as the sphericity.

[0105] <Oil absorption amount> The oil absorption was measured in accordance with JIS K5101-13-1:2004 (ISO 787-5:1980) Pigment Testing Methods - Part 13: Oil Absorption - Section 1: Refined Linseed Oil Method.

[0106] <Surface smoothness> A scanning electron microscope photograph of the particles was taken at 2500 to 6000 magnifications (see, for example, FIG. 3, which is a microscope photograph of the cellulose acetate particles of Example A-1 taken with an "SU5000" product name manufactured by Hitachi High-Technologies Corporation), and the image was binarized using an image processing device Winroof (manufactured by Mitani Shoji Co., Ltd.) (see FIG. 4, which is a binarized image of the microscope photograph of FIG. 3). From the binarized image, a region including the center and / or the vicinity of the center of a single particle was randomly selected, and the area ratio of the concave portion (shaded portion) of the concave-convex portion in that region was calculated, and the surface smoothness (%) of that single particle was calculated using the following formula. Surface smoothness of one particle (%) = (1 - concave area ratio) x 100 Concave area ratio = concave area in the given area / given area The surface smoothness (%) was determined as the average value of the surface smoothness of 10 randomly selected particle samples, i.e., n1 to n10. The higher this value, the higher the surface smoothness. The region used to calculate the area ratio may be any region smaller than the particle, including the center and / or the vicinity of the center of a single particle. Furthermore, the size of the region may be 5 μm square when the particle diameter is 15 μm.

[0107] <Bulk specific gravity> The bulk density was measured in accordance with JIS K 1201-1.

[0108] <Relative specific surface area: RSSA> Assuming that the particles are spherical fine particles with smooth surfaces, the specific surface area calculated from the results of measuring the particle size distribution is defined as the "theoretical specific surface area," and the specific surface area measured by the BET method is defined as the "measured specific surface area," and the relative specific surface area (RSSA) is defined as the measured specific surface area / theoretical specific surface area.

[0109] The specific surface area is measured by the BET method as follows: The specific surface area using the nitrogen BET specific surface area measurement method can be determined by first heating and evacuating the sample at 100°C for approximately one hour using a Quantachrome Instruments MasterPrep degasser, then measuring the nitrogen adsorption at approximately seven points using a nitrogen gas adsorption method in the relative pressure range of 0.05 to 0.28 using a specific surface area measurement device (Quantachrome Instruments Autosorb iQ Station 2), and then calculating the specific surface area using the BET method.

[0110] <Biodegradable> Biodegradability was evaluated by biodegradation rate. The biodegradation rate was measured using activated sludge according to JIS K6950. Activated sludge was obtained from a municipal wastewater treatment plant. Approximately 300 mL of supernatant (activated sludge concentration: approximately 360 ppm) obtained by leaving the activated sludge for approximately one hour was used per culture bottle. Measurements began when 30 mg of sample was stirred in the supernatant, and measurements were then taken every 24 hours for a total of 31 times until 720 hours, or 30 days, elapsed. The details of the measurements are as follows: The biochemical oxygen demand (BOD) in each culture bottle was measured using an Okura Electric Co., Ltd. Coulometer OM3001. The biodegradation rate (wt%) was calculated as the percentage of the biochemical oxygen demand (BOD) relative to the theoretical BOD for complete decomposition based on the chemical composition of each sample. Biodegradability was evaluated as follows: ◎: More than 60% by weight, ○: 40% by weight or more and 60% by weight or less, △: 10% by weight or more and less than 40% by weight, ×: Less than 10% by weight

[0111] <Tactile sensation> The texture of the particles was evaluated by a panel of 20 people. The particles were touched and evaluated comprehensively for softness, smoothness, and moistness according to the following criteria, with a maximum of 5 points. The average score of the 20 people was calculated. Good: 5, Fair: 4, Average: 3, Fair: 2, Bad: 1

[0112] <Scanning electron microscope (SEM) image> Scanning electron microscope (SEM) images were obtained at magnifications of 3000x, 5000x, and 6000x. Images at 3000x and 5000x were taken using a scanning electron microscope (product name "TM3000") manufactured by Hitachi High-Technologies Corporation, and images at 6000x were taken using a scanning electron microscope (product name "SU5000") manufactured by the same company.

[0113] (Examples A-2 to A-3, A-5, and A-7 to A-12) Cellulose acetate particles were obtained in the same manner as in Example A-1, except that the types and amounts of the plasticizer, first thermoplastic resin, and second thermoplastic resin were changed as shown in Table 1. The physical properties of the obtained cellulose acetate particles were evaluated using the above-mentioned measurement methods. The results are shown in Table 1. Scanning electron microscope (SEM) images of Example A-1 are shown in Figure 1 (3000x), Figure 2 (5000x), and Figure 3 (6000x), and SEM images of Example A-12 are shown in Figure 5 (3000x) and Figure 6 (5000x).

[0114] (Examples A-4 and A-6) In Example A-4, cellulose acetate was replaced with cellulose diacetate (manufactured by Daicel Corporation, total acetyl substitution degree DS = 2.8, SP value: 22.6 (MPa 1 / 2 In Example A-6, the cellulose acetate was replaced with cellulose diacetate (manufactured by Daicel Corporation, total acetyl substitution degree DS = 1.8, SP value: 26 (MPa 1 / 2 )). Cellulose acetate particles were obtained in the same manner as in Example A-1, except that the types and amounts of the plasticizer, first thermoplastic resin, and second thermoplastic resin were changed as shown in Table 1. The physical properties of the obtained cellulose acetate particles were evaluated using the above-mentioned measurement methods. The results are shown in Table 1.

[0115] (Comparative examples A-1~3, 5, 7~11) Cellulose acetate particles were obtained in the same manner as in Example A-1, except that the type and amount of the plasticizer and the first thermoplastic resin were changed as shown in Table 2 and the second thermoplastic resin was not added. The physical properties of the obtained cellulose acetate particles were evaluated using the above-mentioned measurement methods. The results are shown in Table 2. Scanning electron microscope (SEM) images of Comparative Example A-1 are shown in Figure 7 (3000x magnification) and Figure 8 (5000x magnification).

[0116] (Comparative Examples A-4 and A-6) In Comparative Example A-4, cellulose acetate was replaced with cellulose diacetate (manufactured by Daicel Corporation, total acetyl substitution degree DS = 2.8, SP value: 22.6 (MPa 1 / 2 In Comparative Example A-6, the cellulose acetate was replaced with cellulose diacetate (manufactured by Daicel Corporation, total acetyl substitution degree DS = 1.8, SP value: 26 (MPa 1 / 2 Cellulose acetate particles were obtained in the same manner as in Example A-1, except that the temperature was changed to ), the type and amount of the plasticizer and the first thermoplastic resin were changed as shown in Table 2, and the second thermoplastic resin was not added. The physical properties of the obtained cellulose acetate particles were evaluated using the above-mentioned measurement methods. The results are shown in Table 2.

[0117] (Comparative Examples A-12~15) Cellulose acetate particles were obtained in the same manner as in Example A-1, except that the types and amounts of the first thermoplastic resin and the second thermoplastic resin were changed as shown in Table 3. The physical properties of the obtained cellulose acetate particles were evaluated using the above-mentioned measurement methods. The results are shown in Table 3.

[0118] [Table 1]

[0119] [Table 2]

[0120] [Table 3]

[0121] As shown in Table 1-3, all of the cellulose acetate particles of the Examples have excellent biodegradability, excellent touch, particularly soft touch, and excellent oil absorbency.

[0122] (Example B-1) Preparation of liquid foundation The components shown in Table 4 were mixed, stirred thoroughly, and poured into a container to prepare a liquid foundation. The texture of the resulting liquid foundation was evaluated using the following method. The results are shown in Table 12. [Table 4]

[0123] <Tactile sensation> The compositions prepared by blending the particles were subjected to a sensory evaluation by a panel of 20 people. Each composition was used and evaluated comprehensively for both smoothness and moisturizing feeling according to the following criteria, with a maximum of 5 points. The average score of the 20 people was calculated. Good: 5, Fair: 4, Average: 3, Fair: 2, Bad: 1

[0124] (Example B-2) Preparation of sunscreen The ingredients shown in Table 5 were mixed, stirred thoroughly, and filled into containers to prepare sunscreens. The texture of the resulting sunscreens was evaluated using the method described above. The results are shown in Table 12. [Table 5]

[0125] (Example B-3) Preparation of powder foundation After roughly mixing the components A shown in Table 6, the homogeneously dissolved component B was added and stirred thoroughly, and the mixture was then poured into a container to prepare a powder foundation. The texture of the resulting powder foundation was evaluated using the method described above. The results are shown in Table 12. [Table 6]

[0126] (Example B-4) Preparation of makeup base Component C shown in Table 7 was dispersed in component A and mixed thoroughly. Component B was added, mixed, and the mixture was poured into a container to prepare a makeup base. The texture of the resulting makeup base was evaluated using the method described above. The results are shown in Table 12. [Table 7]

[0127] (Example B-5) Preparation of lipstick base Component B shown in Table 8 was heated to 60°C and mixed thoroughly. Component C was added to this and thoroughly dispersed. Component A was then added, dissolved using a microwave oven, and mixed thoroughly. The mixture was then heated and dissolved again using a microwave oven, poured into a mold, and allowed to cool and solidify. This was placed in a lipstick container to prepare a lipstick base. The texture of the resulting lipstick base was evaluated using the method described above. The results are shown in Table 12. [Table 8]

[0128] (Example B-6) Preparation of body powder The ingredients A shown in Table 9 were thoroughly mixed using a mixer. The resulting powder was filled into a container to prepare a body powder. The texture of the resulting body powder was evaluated using the method described above. The results are shown in Table 12. [Table 9]

[0129] (Example B-7) Preparation of solid white powder The pressed powder was prepared according to the usual cosmetic manufacturing method. Specifically, the talc and color pigments shown in Table 10 were mixed in a blender. Furthermore, all of the powder components, including the cellulose acetate particles and the color pigments and talc previously mixed in the blender, were mixed using a Henschel mixer. Oil (binder) was then added, the mixture was heated to 70°C, and further mixed, followed by a pulverization step if necessary. The mixture was compression-molded into a metal container to prepare a pressed powder. The texture of the resulting pressed powder was evaluated using the method described above. The results are shown in Table 12. [Table 10]

[0130] (Example B-8) Preparation of solid powder eye shadow The powders shown in Table 11 were thoroughly mixed, and then the binder was dissolved uniformly and added to the powder mixture. The mixture was then further mixed and compression-molded to prepare a solid powder eye shadow. The texture of the resulting solid powder eye shadow was evaluated using the method described above. The results are shown in Table 12. [Table 11]

[0131] (Example B-9) A liquid foundation was prepared in the same manner as in Example B-1, except that Example A-1: ​​cellulose acetate particles in Table 4 were replaced with Example A-12: cellulose acetate particles. The feel of the resulting liquid foundation was evaluated using the method described above. The results are shown in Table 12.

[0132] (Example B-10) A sunscreen was prepared in the same manner as in Example B-2, except that Example A-1: ​​cellulose acetate particles in Table 5 was replaced with Example A-12: cellulose acetate particles. The tactile feel of the resulting sunscreen was evaluated by the method described above. The results are shown in Table 12.

[0133] (Example B-11) A powder foundation was prepared in the same manner as in Example B-3, except that Example A-1: ​​cellulose acetate particles in Table 6 were replaced with Example A-12: cellulose acetate particles. The texture of the obtained powder foundation was evaluated by the method described above. The results are shown in Table 12.

[0134] (Example B-12) A makeup base was prepared in the same manner as in Example B-4, except that Example A-1: ​​cellulose acetate particles in Table 7 was replaced with Example A-12: cellulose acetate particles. The texture of the obtained makeup base was evaluated by the method described above. The results are shown in Table 12.

[0135] (Example B-13) A liquid foundation was prepared in the same manner as in Example B-1, except that Example A-1: ​​cellulose acetate particles in Table 4 were replaced with Example A-12: cellulose acetate particles. The feel of the resulting liquid foundation was evaluated using the method described above. The results are shown in Table 12.

[0136] (Example B-14) A sunscreen was prepared in the same manner as in Example B-2, except that Example A-1: ​​cellulose acetate particles in Table 5 was replaced with Example A-12: cellulose acetate particles. The tactile feel of the resulting sunscreen was evaluated by the method described above. The results are shown in Table 12.

[0137] (Example B-15) A liquid foundation was prepared in the same manner as in Example B-1, except that Example A-1: ​​cellulose acetate particles in Table 4 were replaced with Example A-12: cellulose acetate particles. The feel of the resulting liquid foundation was evaluated using the method described above. The results are shown in Table 12.

[0138] (Example B-16) A sunscreen was prepared in the same manner as in Example B-2, except that Example A-1: ​​cellulose acetate particles in Table 5 was replaced with Example A-12: cellulose acetate particles. The tactile feel of the resulting sunscreen was evaluated by the method described above. The results are shown in Table 12.

[0139] (Example B-17) A liquid foundation was prepared in the same manner as in Example B-1, except that the cyclopentasiloxane in Table 4 was replaced with a mixture of equal weights of dodecane (PARAFOL 12-97 (Sasol)) and Cetiol Ultimate (undecane:tridecane = 65% by weight:35% by weight, manufactured by BASF), the isononyl isononanoate was replaced with a mixture of equal weights of coconut oil alkyl caprylate (Cetiol C5 (BASF)), coconut (caprylate / caprate) alkyl (Cetiol CC (BASF)), and dicaprylyl carbonate (Cetiol CC (BASF)), and the phytosteryl macadamiate was replaced with camellia oil (Pure Camellia Oil (Nikko Rica)). The texture of the resulting liquid foundation was evaluated using the method described above. The results are shown in Table 12.

[0140] (Example B-18) Sunscreens were prepared in the same manner as in Example B-2, except that isododecane in Table 5 was replaced with a mixture of equal weights of dodecane (PARAFOL 12-97 (Sasol)) and Cetiol Ultimate (undecane:tridecane = 65% by weight:35% by weight, manufactured by BASF), and diisopropyl sebacate was replaced with a mixture of equal weights of coco-caprylate (Cetiol C5 (BASF)), coco-caprylate / caprate (Cetiol CC (BASF)), and dicaprylyl carbonate (Cetiol CC (BASF)). The tactile feel of the resulting sunscreens was evaluated using the method described above. The results are shown in Table 12.

[0141] (Example B-19) A powder foundation was prepared in the same manner as in Example B-3, except that dimethicone in Table 6 was replaced with a mixture of equal weights of dodecane (PARAFOL 12-97 (Sasol)) and Cetiol Ultimate (undecane:tridecane = 65% by weight:35% by weight, manufactured by BASF), and octyldodecyl oleate was replaced with a mixture of equal weights of coconut oil alkyl caprylate (Cetiol C5 (BASF)), coconut (caprylate / caprate) (Cetiol CC (BASF)), and dicaprylyl carbonate (Cetiol CC (BASF)). The texture of the resulting powder foundation was evaluated using the method described above. The results are shown in Table 12.

[0142] (Example B-20) A makeup base was prepared in the same manner as in Example B-4, except that cyclomethicone in Table 7 was replaced with a mixture of equal weights of dodecane (PARAFOL 12-97 (Sasol)) and Cetiol Ultimate (undecane:tridecane = 65% by weight:35% by weight, manufactured by BASF), and isononyl isononanoate was replaced with a mixture of equal weights of coconut oil alkyl caprylate (Cetiol C5 (BASF)), coconut (caprylate / caprate) (Cetiol CC (BASF)), and dicaprylyl carbonate (Cetiol CC (BASF)). The texture of the resulting makeup base was evaluated using the method described above. The results are shown in Table 12.

[0143] (Example B-21) A powder foundation was prepared in the same manner as in Example B-3, except that the mica Y-2300X in Table 6 was replaced with a mixture of equal weights of mica (Mica Y-2300X (Yamaguchi Mica)), synthetic mica (PDM-10L (Topy Industries)), and (fluoride / hydroxide / oxide) / (Mg / K / silicon) (Micromica MK-200K (Katakura Co-op Agri)), the sericite was replaced with a mixture of equal weights of barium sulfate (plate-shaped barium sulfate H (Sakai Chemical Industry Co., Ltd.)) and boron nitride (SHP-6 (Mizushima Ferroalloy)), and the talc was replaced with a mixture of equal weights of cellulose (NP Fiber W-06MG (Nippon Paper Industries)) and silica (Godball E-16C (Suzuki Oil & Fat Industries)). The texture of the resulting powder foundation was evaluated using the method described above. The results are shown in Table 12.

[0144] (Example B-22) A body powder was prepared in the same manner as in Example B-6, except that the talc in Table 9 was replaced with a mixture of equal weights of cellulose (NP Fiber W-06MG (Nippon Paper Industries)) and silica (Godball E-16C (Suzuki Oil & Fat Industries)). The texture of the resulting body powder was evaluated by the method described above. The results are shown in Table 12.

[0145] (Example B-23) Solid powder eye shadows were prepared in the same manner as in Example B-8, except that the mica Y-2300X in Table 11 was replaced with a mixture of equal weights of mica (Mica Y-2300X (Yamaguchi Mica)), synthetic mica (PDM-10L (Topy Industries)), and (fluoride / hydroxide / oxide) / (Mg / K / silicon) (Micromica MK-200K (Katakura Co-op Agri)), and the sericite was replaced with a mixture of equal weights of barium sulfate (platy barium sulfate H (Sakai Chemical Industry Co., Ltd.)) and boron nitride (SHP-6 (Mizushima Ferroalloy)). The texture of the resulting solid powder eye shadows was evaluated using the method described above. The results are shown in Table 12.

[0146] (Example B-24) A liquid foundation was prepared in the same manner as in Example B-1, except that BG in Table 4 was replaced with a mixture of equal weights of glycerin and pentylene glycol (Diol PD (Kyukyu Alcohol Kogyo)). The texture of the resulting liquid foundation was evaluated using the method described above. The results are shown in Table 12.

[0147] (Example B-25) Sunscreens were prepared in the same manner as in Example B-2, except that BG in Table 5 was replaced with a mixture of equal weights of glycerin and pentylene glycol (Diol PD (Kyukyu Alcohol Kogyo)). The texture of the resulting sunscreens was evaluated using the method described above. The results are shown in Table 12.

[0148] (Example B-26) A makeup base was prepared in the same manner as in Example B-4, except that the 1,3-butylene glycol in Table 7 was replaced with a mixture of equal weights of glycerin and pentylene glycol (Diol PD (Kyukyu Alcohol Kogyo)). The texture of the resulting makeup base was evaluated using the method described above. The results are shown in Table 12.

[0149] (Comparative examples B-1~8) In Comparative Examples B-1 to B-8, a liquid foundation, a sunscreen, a powder foundation, a makeup base, a lipstick base, a body powder, a pressed face powder, and a pressed powder eye shadow were prepared in the same manner as in Examples B-1 to B-8, respectively, except that the cellulose acetate particles of Example A-1 in Tables 4 to 11 were replaced with the cellulose acetate particles of Comparative Example A-1. The texture of each product was evaluated using the method described above. The results are shown in Table 13.

[0150] [Table 12]

[0151] [Table 13]

[0152] As shown in Tables 12 and 13, the cosmetic compositions containing the cellulose acetate particles of Examples B-1 to B-26 all had a particularly soft and excellent feel of 4.0 or more. In addition, since all of them contain cellulose acetate particles, they have excellent biodegradability.

Claims

1. Cellulose acetate particles, the cellulose acetate particles have an average particle size of 80 nm to 100 μm, a sphericity of 0.7 to 1.0, and a relative specific surface area of ​​3.0 to 20; The cellulose acetate particles have a total degree of acetyl substitution of 0.7 or more and 3.0 or less.

2. 2. The cellulose acetate particles according to claim 1, having a surface smoothness of 10% or more and 95% or less.

3. 3. The cellulose acetate particles according to claim 1, having a bulk density of 0.2 to 0.

7.

4. 4. The cellulose acetate particles according to claim 1, wherein the oil absorption using linseed oil is 60 ml or more per 100 g of the cellulose acetate particles.

5. 5. The cellulose acetate particles according to claim 1, wherein the cellulose acetate has a total degree of acetyl substitution of 1.6 or more and less than 2.

9.

6. 6. The cellulose acetate particles according to claim 1, wherein the relative specific surface area is 10 or more and 20 or less.

7. the cellulose acetate particles contain a plasticizer, 7. The cellulose acetate particles according to claim 1, wherein the content of the plasticizer is 2 parts by weight or more and 67 parts by weight or less per 100 parts by weight of the cellulose acetate.

8. The cellulose acetate particles according to claim 7 , wherein the plasticizer comprises at least one selected from the group consisting of citric acid-based plasticizers, glycerin ester-based plasticizers, and phthalic acid-based plasticizers.

9. A cosmetic composition comprising the cellulose acetate particles according to any one of claims 1 to 8.

10. a step of mixing cellulose acetate having a total degree of acetyl substitution of 0.7 to 3.0, a plasticizer, a first thermoplastic polymer, and a second thermoplastic polymer to obtain a cellulose acetate mixture containing the plasticizer, the first thermoplastic polymer, and the second thermoplastic polymer; A step of melt-kneading the mixture at 200°C or higher and 280°C or lower; removing the first thermoplastic polymer and the second thermoplastic polymer from the melt-blended mixture; A method for producing cellulose acetate particles, wherein SPa is the SP value of the cellulose acetate, SPb is the SP value of the first thermoplastic polymer, and SPc is the SP value of the second thermoplastic polymer, and SPa, SPb, and SPc satisfy the following relationship: 0.1≦|SPc-SPa| / |SPb-SPa|≦0.9

11. The method for producing cellulose acetate particles according to claim 10, wherein the plasticizer comprises at least one selected from the group consisting of acetyltriethyl citrate and triacetin.

12. 12. The method for producing cellulose acetate particles according to claim 10, wherein the first thermoplastic polymer comprises at least one selected from the group consisting of polyvinyl alcohol and thermoplastic starch.

13. The method for producing cellulose acetate particles according to any one of claims 10 to 12, wherein the second thermoplastic polymer is polyethylene glycol.

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