Resin bead, method for producing resin bead, and product using resin bead

Abstract

To provide a resin bead that serves as an alternative to resin particles made of petroleum-derived synthetic materials, capable of providing various products such as cosmetics having excellent texture and skin spreadability.SOLUTION: A resin bead comprising a filler and a resin portion enclosing the filler, wherein the resin portion contains cellulose having a degree of crystallinity of 50% or less as calculated by the following formula (1): Crystallinity (%)={(A-B) / A}×100 (1), where A: peak intensity of the diffraction peak at a diffraction angle 2θ=21.8°±0.3° measured by X-ray diffraction using Cu-Kα radiation as the X-ray source. B: Peak intensity of the diffraction peak at a diffraction angle 2θ=15.0°±0.3° measured by X-ray diffraction using Cu-Kα radiation as the X-ray source.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to resin beads, a method for producing the resin beads, and a product obtained using the resin beads.

Background Art

[0002] Conventionally, due to their spherical properties, resin beads have been used in various fields such as matting agents, lubricants, and anti-blocking agents. Furthermore, various resin powders (resin particles) such as resin beads are used to improve properties such as the spreadability of cosmetics for makeup. However, in recent years, due to problems such as marine pollution caused by microplastics, the constituent materials of resin beads incorporated in cosmetics are shifting from petroleum-derived synthetic materials to natural materials.

[0003] As spherical resin particles made of natural materials, for example, powdery cellulose useful as a scrubbing agent has been proposed (Patent Document 1). Furthermore, cellulose derivative fine particles used in diagnostic agents (Patent Document 2) and spherical cellulose powder used in cosmetics (Patent Documents 3 and 4) have been proposed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, powdery cellulose and the like proposed in Patent Document 1 were not suitable in terms of particle size as an agent to be blended in cosmetics for makeup or skin care. Further, the cellulose derivative fine particles proposed in Patent Document 2 required the use of copper ammonia during production, and thus were not necessarily suitable as a material for cosmetics that aim to reduce heavy metals as much as possible.

[0006] Furthermore, spherical cellulose powder and the like proposed in Patent Documents 3 and 4 had high cohesiveness, and even when blended in cosmetics, the elongation with respect to the skin was not so good, and a rough feeling was easily felt. Also, the texture was likely to change greatly when wetted or blended in a solution. For this reason, when blended in cosmetics, the cosmetics themselves were likely to become unstable, and thus they were not necessarily suitable as a material for cosmetics.

[0007] The present invention has been made in view of such problems of the prior art, and an object thereof is to provide resin beads that can replace resin particles made of petroleum-derived synthetic materials, and various products such as cosmetics, which have excellent touch and elongation to the skin. Another object of the present invention is to provide a method for producing resin beads that can replace resin particles made of petroleum-derived synthetic materials, and various products such as cosmetics, which have excellent touch and elongation to the skin.

Means for Solving the Problems

[0008] That is, according to the present invention, resin beads shown below are provided. [1] Resin beads having a filler and a resin part that encapsulates the filler, wherein the resin part contains cellulose having a crystallinity of 50% or less calculated by the following formula (1). Crystallinity (%) = {(A - B) / A} × 100 ···(1) A: Peak intensity of the diffraction peak at a diffraction angle 2θ = 21.8° ± 0.3° measured by X-ray diffraction using Cu-Kα rays as an X-ray source B: Peak intensity of diffraction peak with diffraction angle 2θ = 15.0° ± 0.3° measured by X-ray diffraction using Cu-Kα line as X-ray source [2] The resin beads according to [1], wherein the cellulose is a hydrolyzate of a cellulose derivative. [3] The resin beads according to [2], wherein the cellulose derivative is a cellulose ester. [4] The resin beads according to any one of [1] to [3], wherein the average particle diameter of the filler is 2 μm or less. [5] The resin beads according to any one of [1] to [4], wherein the filler is at least one selected from the group consisting of inorganic particles and pigments. [6] The resin beads according to any one of [1] to [4], wherein the filler is at least one selected from the group consisting of metal salts and metal oxides. [7] The resin beads according to [6], wherein the metal salt is at least one selected from the group consisting of barium sulfate and calcium carbonate, and the metal oxide is at least one selected from the group consisting of titanium oxide, zinc oxide, and aluminum oxide.

[0009] Further, according to the present invention, there is provided a method for producing the following resin beads. [8] A method for producing the resin beads according to any one of [1] to [7], comprising: mixing an oil phase containing a filler, a cellulose derivative, and an organic solvent having a solubility of 0.1 to 50.0 g in 100 g of water at 25°C for dissolving the cellulose derivative with an aqueous phase containing a dispersion stabilizer to prepare a suspension containing oil droplets containing the filler, the cellulose derivative, and the organic solvent; removing the organic solvent from the oil droplets in the suspension to form resin particles containing the filler and the cellulose derivative; and hydrolyzing the cellulose derivative in the resin particles to form cellulose. [9] The method for producing resin beads according to [8], wherein water is added to the suspension, the organic solvent is removed from the oil droplets in the suspension, and the oil droplets are shrunk to form the resin particles.

[0010] Furthermore, according to the present invention, the following products are provided.

[10] A product selected from the group consisting of cosmetics, skin medications, paints, molded articles, films, coating agents, and resin compositions, containing resin beads, wherein the resin beads are the resin beads according to any one of [1] to [7].

Advantages of the Invention

[0011] According to the present invention, it is possible to provide resin beads that can replace resin particles made of petroleum-derived synthetic materials and various products such as cosmetics having excellent touch and elongation on the skin, and various products such as cosmetics using the same. Further, according to the present invention, it is possible to provide a method for producing resin beads that can replace resin particles made of petroleum-derived synthetic materials and can provide various products such as cosmetics having excellent touch and elongation on the skin.

Embodiments for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments. Note that various physical property values in this specification are values at normal temperature (25°C) unless otherwise specified.

[0013] The present inventor has variously studied resin beads made of natural-based materials with good biodegradability and a method for producing the same, which can provide various products such as cosmetics having excellent touch and elongation on the skin. As a result, it has been found that by adopting the configuration shown below, resin beads can be obtained that are mainly composed of natural-based materials and can provide various products such as cosmetics having the above-described various characteristics. That is, one embodiment of the resin beads of the present invention has a filler and a resin part that encloses the filler. And the resin part contains cellulose having a crystallinity of 50% or less calculated by the following formula (1). Note that it is preferable that the resin part is substantially formed only of cellulose having a crystallinity of 50% or less calculated by the following formula (1). Crystallinity (%) = {(A - B) / A} × 100 ···(1) A: Peak intensity of the diffraction peak at diffraction angle 2θ = 21.8° ± 0.3° measured by X-ray diffraction using Cu-Kα line as the X-ray source B: Peak intensity of the diffraction peak at diffraction angle 2θ = 15.0° ± 0.3° measured by X-ray diffraction using Cu-Kα line as the X-ray source

[0014] Cellulose is usually composed of a crystalline part and an amorphous part, and exhibits various functions as a material that supports plants. In order to utilize such functions, there are cases where natural cellulose itself is directly used, cases where a cellulose derivative obtained by chemically changing the structure of natural cellulose is used, and cases where regenerated cellulose chemically regenerated is used. As the crystal form of cellulose, type I of natural cellulose, type II of regenerated cellulose, etc. are known. And the diffraction peaks of regenerated cellulose type II measured by X-ray diffraction exist near diffraction angles 2θ ≒ 12°, 20°, and 22°. Note that the shape and intensity of each diffraction peak differ depending on the production method of the regenerated cellulose.

[0015] The crystallinity of the cellulose (cellulose type II crystal) contained in the resin part constituting the resin beads of the present embodiment is 50% or less, preferably 40% or less, more preferably 30% or less. Note that the substantial lower limit of the crystallinity is 0°. By setting the crystallinity of the cellulose constituting the resin part within the above range, the crystallinity and cohesiveness of the resin part can be relaxed. Therefore, by using resin beads having a resin part containing cellulose whose crystallinity is within the above range, various products such as cosmetics having excellent touch and elongation to the skin can be provided.

[0016] If the crystallinity of cellulose is too high, the resin part becomes tough and hard, the cohesiveness during drying increases and it becomes difficult to pulverize, and the yield may decrease because classification is necessary. Also, if the crystallinity of cellulose is too high, the resin beads are difficult to roll, the smoothness decreases, and it becomes rough and the touch significantly deteriorates.

[0017] The X-ray diffraction peak of cellulose can be measured using a commercially available X-ray diffractometer (e.g., trade name "Miniflex600" (manufactured by Rigaku Corporation)). Specifically, finely pulverized resin beads (resin part containing cellulose) are pressed against a holder and measured by scanning in the range of diffraction angle 2θ = 5 to 30°. As the X-ray source, Cu-Kα ray (40 kV, 15 mA) monochromatized with a Kβ filter is used.

[0018] The crystallinity of cellulose can be calculated from the above formula (1) using the peak intensity (A) of the diffraction peak at diffraction angle 2θ = 21.8° ± 0.3° corresponding to the crystalline part and the non-crystalline part, and the peak intensity (B) of the diffraction peak at diffraction angle 2θ = 15.0° ± 0.3° corresponding to the non-crystalline part. When the crystallinity calculated from the above formula (1) is negative (-), the crystallinity is set to 0%.

[0019] The cellulose contained in the resin part is preferably a hydrolysis product of a cellulose derivative. The resin part may also contain cellulose and a cellulose derivative. From the viewpoint of enhancing the biodegradability of the resin beads, the content of cellulose in the resin part is preferably 50 to 100% by mass, more preferably 60 to 100% by mass, and particularly preferably 70 to 100% by mass. That is, the resin part is preferably substantially formed only of cellulose.

[0020] The cellulose contained in the resin part may be pre-blended in the resin part from the beginning of the production of the resin beads, or may be produced by chemically modifying a cellulose derivative during the production process of the resin beads. The crystal form of the cellulose pre-blended in the resin part may be either type I or type II.

[0021] The cellulose derivative is a modified cellulose having three hydroxy groups in one unit. The cellulose derivative may be any of those in which one hydroxy group in one unit is modified, two hydroxy groups are modified, and three hydroxy groups are modified. The structure of the group for modifying the hydroxy group may be any of linear, branched, and cyclic. Also, the cellulose derivative may be a salt.

[0022] As the cellulose derivative, a known cellulose derivative can be appropriately selected and used in consideration of the purpose of use of the resin beads and the like. Examples of the cellulose derivative include methyl cellulose, ethyl cellulose, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, nitrocellulose, hydroxypropyl methyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose phthalate, hypromellose acetate succinate, carboxymethyl cellulose, and cellulose glycolic acid ether. As cellulose acetate, acetyl cellulose, diacetyl cellulose, and triacetyl cellulose can be mentioned.

[0023] The cellulose derivative is preferably a cellulose ester used in products such as cosmetics as a natural cellulose derivative. Examples of the cellulose ester include cellulose fatty acid ester, cellulose organic acid ester, and cellulose phosphate ester. Among them, the cellulose ester is preferably at least one selected from the group consisting of cellulose acetate, cellulose propionate, cellulose acetate propionate, cellulose butyrate, and cellulose acetate butyrate.

[0024] The cumulative volume-based 50% particle diameter (median diameter; D 50 ) of the resin beads is preferably 50 μm or less, more preferably 30 μm or less, particularly preferably 0.1 to 30 μm, and most preferably 0.5 to 20 μm. D50 By setting it within the above range, the slipperiness required for resin beads blended in cosmetics and the like can be more effectively exhibited.

[0025] The cumulative 90% particle diameter (D 90 ) of the resin beads is preferably 40 μm or less, and more preferably 5 - 25 μm. Also, the cumulative 10% particle diameter (D 10 ) of the resin beads is preferably 0.1 μm or more, and more preferably 1.5 - 10 μm. And the CV value (coefficient of variation) of the particle diameter of the resin beads is preferably 10 - 90%. By setting D 90 , D 10 , and the CV value within the above ranges respectively, the smoothness without a foreign body feeling required for resin beads blended in cosmetics and the like can be more effectively exhibited, and a cosmetic with suppressed entry into wrinkles can be obtained. Note that the cumulative 50% particle diameter (D 50 ), cumulative 10% particle diameter (D 10 ), and cumulative 90% particle diameter (D 90 ) of the resin beads can be measured using a Coulter counter (manufactured by Beckman Coulter).

[0026] The sphericity of the resin beads is preferably 0.5 or more and 1.0 or less, more preferably 0.6 - 1.0 or less, and particularly preferably 0.7 - 1.0 or less. By setting the sphericity within the above range, the good touch and elongation to the skin required for resin beads blended in cosmetics and the like can be effectively exhibited.

[0027] The sphericity, which is an index indicating whether the resin beads are spherical or not, can be measured and calculated according to the following procedure. First, the SEM image of the resin beads taken by a scanning electron microscope (SEM) is subjected to image analysis, and the circularity C of each resin bead is calculated from the following formula (2). Then, the arithmetic mean value of the circularity C of 10 or more arbitrarily selected resin beads is taken as the sphericity. C = (4πS1) / (L 2 ) ···(2)

[0028] In the above formula (2), S1 represents the area (projection area) of the resin beads in the image, and L represents the length of the outer peripheral part of the resin beads in the image. The closer the value of the circularity C is to 1, the closer the shape of the particles is to a perfect sphere.

[0029] The surface smoothness of the resin beads is preferably 50 to 100%, more preferably 60 to 100%, and particularly preferably 70 to 100%. By setting the surface smoothness within the above range, the good touch feeling required for the resin beads blended in cosmetics and the like and the elongation to the skin can be effectively expressed.

[0030] The surface smoothness of the resin beads can be measured according to the following procedure. That is, observe the SEM image (×5,000) of the resin beads taken by a scanning electron microscope (SEM), and calculate the smoothness M of each resin bead from the following formula (3). Then, take the arithmetic mean value of the smoothness M of 10 or more arbitrarily selected resin beads as the surface smoothness. The closer the value of the smoothness M is to 1, the closer the surface of the particles is to being smooth. M = (1 - (S3) / (S2)) × 100 ···(3)

[0031] In the above formula (3), S2 represents the area (projection area) of the resin beads in the image, and S3 represents the sum of the area formed by the contour of the resin particles and the areas inside and outside the contour of the overlapping circle when the resin beads and an approximated circle are overlapped.

[0032] The solid content of the resin beads is preferably 50 to 100% by volume, more preferably 60 to 100% by volume, and particularly preferably 70 to 99% by volume. By setting the solid content within the above range, the low oil absorption amount required for the resin beads blended in cosmetics and the like can be effectively expressed. When the solid content of the resin beads is less than 50% by volume, the oil absorption amount tends to increase. For this reason, when resin beads with a low solid content are blended into products such as cosmetics, the viscosity of the cosmetics and the like may increase, and the stability of the products may be likely to decrease.

[0033] The solidity of the resin beads can be measured and calculated according to the following procedure. First, perform image analysis on the SEM image of the cross-section of the resin beads taken with a scanning electron microscope (SEM) to calculate the volumes of the resin part and the part filled with the filler for each individual resin bead. Then, take the average value of the volumes of the resin part and the part filled with the filler for 10 or more arbitrarily selected resin beads as the solidity (volume %).

[0034] The biodegradation rate of the resin beads over 5 days is preferably 20% or more, more preferably 30% or more, and particularly preferably 40% or more. By setting the biodegradation rate of the resin part within the above range, the good biodegradability required for the resin beads formulated in cosmetics and the like can be exhibited.

[0035] The biodegradation rate of the resin part of the resin beads over 5 days is measured in accordance with JIS K6950:2000 (ISO 14851:1999). More specifically, the biodegradation rate of the resin beads over 5 days is measured and calculated by conducting a test under the following conditions (BOD measurement using a closed-system oxygen consumption measuring device). Seeding source: Aerobic reaction tank sludge from a sewage treatment plant mainly treating domestic sewage Reference substance: Microcrystalline cellulose Test substance concentration: 100 mg / L Reference substance concentration: 100 mg / L Seeding source concentration: 150 mg / L Test solution volume: 300 mL Test temperature: 25 ± 1 °C Culture period: 30 days

[0036] The biodegradation rates of the test substance and the reference substance can be calculated from the following formula. Biodegradation rate (%) = (BODO - BODB) / ThOD × 100 BODO (mg): Biochemical oxygen demand of the test substance BODB (mg): Average biochemical oxygen demand of the reference substance ThOD (mg): Theoretically maximum amount of oxygen required to oxidize the test substance

[0037] The resin beads have a filler and a resin part that encapsulates the filler. That is, the resin beads encapsulate the filler. If the filler is not encapsulated in the resin part and the filler and the resin are simply mixed, the properties peculiar to the filler such as slipperiness, powderyness, and hardness will become apparent, and even if it is blended into cosmetics or the like, the touch and elongation on the skin cannot be effectively expressed. Note that the state of "encapsulating the filler" in this specification means either a state where the entire surface of each filler is covered with the resin part or a state where a part of the surface of each filler is covered with the resin part.

[0038] The average particle diameter of the filler (cumulative 50% particle diameter based on volume (median diameter; D 50 )) is preferably 2 μm or less, more preferably 1.5 μm or less, and particularly preferably 1 μm or less. Note that there is no particular limitation on the lower limit of D 50 of the filler, and substantially 0.01 μm or more is sufficient. D 50 of the filler may be adjusted within the range to be encapsulated in consideration of the particle diameter of the resin beads. If D 50 of the filler is too large with respect to the resin beads, it may be difficult to encapsulate the filler. On the other hand, if D 50 of the filler is too small with respect to the resin beads, the dispersibility is likely to decrease, and the viscosity of the raw material is likely to increase excessively during the production of the resin beads. For this reason, it may be difficult to produce resin beads having the target particle diameter. Note that the cumulative 50% particle diameter (D 50 ) of the filler based on volume can be measured using a Coulter counter (manufactured by Beckman Coulter, Inc.).

[0039] The inclusion rate of the filler in the resin beads is preferably 98% or less, more preferably 97% or less, and particularly preferably 95% or less. The lower limit of the inclusion rate of the filler is not particularly limited, and may be substantially 0.1% or more. The inclusion rate of the filler may be appropriately adjusted so that the crystallinity of cellulose and the like fall within the target range. The state in which the filler is included in the resin beads can be confirmed, for example, by observation using an optical microscope, a scanning electron microscope (SEM), or the like, and image analysis. The inclusion rate of the filler in the resin beads is the ratio (%) of the mass of the filler to the total mass of the filler and the resin part.

[0040] As the filler, glass, polymer, fiber, magnetic material, metal powder, inorganic particles, pigment, cellulose fiber, etc. can be used. Among them, the filler is preferably at least one selected from the group consisting of inorganic particles and pigments. Known inorganic particles and pigments can be used. Examples of the inorganic particles and pigments include carbon black, titanate, magnetic material, ferrite, iron powder, iron oxide, boron nitride, mica, talc, kaolin, aluminum powder, aluminum hydroxide, magnesium hydroxide, alumina, carbon black, Food Color Yellow No. 4, Red No. 202, and Blue No. 1. The inorganic particles and pigments may be surface-treated with at least one selected from the group consisting of silicone, fatty acid, fatty acid metal salt, amino acid, amino acid metal salt, oil, and lipid.

[0041] Also, the filler is preferably at least one selected from the group consisting of metal salts and metal oxides. Known metal salts and metal oxides can be used. Examples of the metal salts and metal oxides include titanium oxide, zinc oxide, red iron oxide, yellow iron oxide, black iron oxide, titanium oxide, zinc oxide, aluminum oxide, barium sulfate, and calcium carbonate. Among them, aluminum oxide, barium sulfate, calcium carbonate, titanium oxide, and zinc oxide are preferred, and barium sulfate is more preferred.

[0042] When manufacturing the resin beads of the present embodiment by the manufacturing method described below, by encapsulating a filler, the crystallinity of cellulose contained in the resin part to be formed can be reduced. Although the reason why the crystallinity of cellulose decreases by encapsulating the filler is not necessarily clear, the present inventor speculates as follows. In the manufacturing method described below, an oil phase containing a filler, a cellulose derivative, and a predetermined organic solvent is prepared. In this oil phase, after a state is formed in which the filler is adsorbed or electrically approaches the polar part of the cellulose derivative, resin particles containing the filler and the cellulose derivative are formed. Then, when the cellulose derivative is hydrolyzed to form cellulose, it is considered that the filler adsorbed or approaching the polar part of the cellulose derivative inhibits the crystallization and crystal growth of cellulose, and the crystallinity of cellulose decreases.

[0043] Inorganic particles and pigments are presumed to interact more strongly with the cellulose derivative. Therefore, from the viewpoint of further reducing the crystallinity of cellulose forming the resin part, it is preferable to use at least one selected from the group consisting of inorganic particles and pigments as the filler. Among inorganic particles and pigments, it is preferable to use at least one selected from the group consisting of metal salts and metal oxides as the filler, and it is more preferable to use aluminum oxide, barium sulfate, calcium carbonate, titanium oxide, zinc oxide, etc., and it is particularly preferable to use barium sulfate.

[0044] The resin part constituting the resin beads may further contain components such as a surfactant, a dispersant, and a polymer dispersant. Further, the resin part constituting the resin beads can contain at least one of an ultraviolet absorber and an ultraviolet scattering agent according to the application. To obtain resin beads having a resin part containing an ultraviolet absorber or an ultraviolet scattering agent, for example, a suspension may be prepared using an oil phase further containing at least one of an ultraviolet absorber and an ultraviolet scattering agent. Examples of the ultraviolet absorber and the like include fine particle titanium dioxide, fine particle zinc oxide, cinnamic acid-based ultraviolet absorbers, dibenzoylmethane-based ultraviolet absorbers, and the like.

[0045] The resin beads may be surface-treated with silicone, fatty acids, fatty acid metal salts, amino acids, amino acid metal salts, oils and fats, lipids, etc. according to the intended use.

[0046] Next, a method for producing the above-described resin beads will be described. One embodiment of the method for producing the resin beads of the present invention is the method for producing the above-described resin beads, which includes a suspension preparation step, a particle formation step, and a hydrolysis step. The suspension preparation step is a step of mixing an oil phase containing a filler, a cellulose derivative, and an organic solvent having a solubility of 0.1 to 50.0 g in 100 g of water at 25°C for dissolving the cellulose derivative with an aqueous phase containing a dispersion stabilizer to prepare a suspension containing oil droplets containing the filler, the cellulose derivative, and the organic solvent. The particle formation step is a step of removing the organic solvent from the oil droplets in the suspension obtained in the suspension preparation step to form resin particles containing the filler and the cellulose derivative. And the hydrolysis step is a step of hydrolyzing (saponifying) the cellulose derivative in the resin particles formed in the particle formation step to form cellulose and produce the target resin beads.

[0047] In the suspension preparation step, an oil phase containing a filler, a cellulose derivative, and an organic solvent for dissolving the cellulose derivative is mixed with an aqueous phase containing a dispersion stabilizer. By mixing the oil phase and the aqueous phase and stirring as necessary, a suspension in which oil droplets containing a cellulose ester and an organic solvent are dispersed in water can be obtained. Since these oil droplets exist in a dispersed state in water, the organic solvent in the oil droplets gradually moves into the water. Along with the movement of the organic solvent, the oil droplets shrink, and the cellulose derivative dissolved in the organic solvent gradually precipitates while coating the filler. The precipitated cellulose derivative grows while enclosing the filler and maintaining a smooth surface. Finally, the precipitated cellulose derivative is immobilized, and resin particles serving as precursors of resin beads are formed. Whether or not the oil droplets are shrinking can be determined by analyzing an image observed using an optical microscope, an electron microscope, or the like. By shrinking the oil droplets in this way, resin beads having a desired particle diameter, high sphericity (roundness), high solidity, and a smooth surface can be obtained.

[0048] As the cellulose derivative, the aforementioned cellulose derivatives including cellulose esters can be used. By hydrolyzing at least a part of the ester bonds in the cellulose ester in the hydrolysis step described later, physical properties suitable for cosmetic applications such as touch feeling and elongation on the skin can be maintained. That is, by selecting the hydrolysis conditions, defects generated when cellulose is produced can be suppressed, and resin beads that can be suitably formulated in cosmetics and the like can be obtained.

[0049] As the cellulose ester, it is preferable to use a cellulose ester having an acyl group content of 60% by mass or less, such as an acetyl group, a propionyl group, and a butyroyl group. Among them, it is preferable to use cellulose acetate or cellulose acetate propionate having an acyl group content of 60% by mass or less. Further, it is preferable to use a cellulose ester having a viscosity of 200 mPa·s or less in a 6% by mass acetone solution. When these cellulose esters are used, defects such as particle size distribution and touch feeling of the obtained resin beads are less likely to occur, and resin beads that can be suitably blended in cosmetics and the like can be obtained more easily.

[0050] As the cellulose derivative, a commercially available cellulose derivative may be used as it is, or one obtained by hydrolyzing or esterifying according to a conventional method to adjust the acyl group content may be used. Further, a plurality of resin beads having different acyl groups may be mixed and controlled so that the acyl group of the whole resin beads is within a predetermined range.

[0051] As the organic solvent (first organic solvent) contained in the oil phase, a known organic solvent capable of dissolving the cellulose derivative can be used. Specific examples of the organic solvent include ester solvents such as methyl formate, ethyl formate, methyl acetate, ethyl acetate, and butyl acetate; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; alcohols such as ethanol and n-butanol; ether solvents such as ethyl cellosolve, butyl cellosolve, and ethylene glycol diethyl ether; glycol ether solvents such as dipropylene glycol monomethyl ether; glycol ester solvents such as propylene glycol monomethyl ether acetate; chlorine solvents such as methylene chloride, chloroform, and tetrachloroethane; nitromethane; propylene carbonate, etc. can be used. These organic solvents can be used alone or in combination of two or more.

[0052] As the organic solvent, ketone solvents, ester solvents, alcohols, glycols, ether solvents, alkyl halides, and nitrated alkyls are preferred. Among them, methyl ethyl ketone, ethyl acetate, butanol, propylene glycol monobutyl ether, propyl acetate, and propylene glycol monomethyl ether acetate are more preferred.

[0053] If the water solubility of the organic solvent in the oil droplets contained in the suspension is too high, the organic solvent easily moves rapidly from the oil droplets to the aqueous phase during suspension, so that the resin beads formed by shrinking the oil droplets may not easily become spherical or may not easily form a smooth surface. On the other hand, if the water solubility of the organic solvent is too low, the organic solvent may easily remain in the resin beads. Therefore, the solubility of the organic solvent in 100 g of water (water solubility) at 25°C is 0.1 to 50.0 g, preferably 0.5 to 40.0 g, and more preferably 1.0 to 30.0 g.

[0054] The liquid amount of the organic solvent contained in the oil phase (the first liquid) is preferably 2.0 times or more, more preferably 2.5 to 15.0 times, based on the mass of the cellulose derivative. If the liquid amount of the organic solvent in the oil phase is too small, the cellulose derivative is likely to precipitate rapidly when removing the organic solvent from the oil droplets in the suspension in the subsequent atomization step. For this reason, the resulting resin beads may not easily become spherical or may not easily form a smooth surface.

[0055] The aqueous phase used in the suspension preparation step is a liquid (the second liquid) in which a dispersion stabilizer is dissolved in water such as deionized water. As the dispersion stabilizer, water-soluble polymers such as water-soluble cellulose, polyvinyl alcohol, and sodium polyacrylate; inorganic salts such as hydroxyapatite, tricalcium phosphate, and calcium carbonate can be used. These dispersion stabilizers can be used alone or in combination of two or more. Among these dispersion stabilizers, it is preferable to use water-soluble polymers such as water-soluble cellulose, polyvinyl alcohol, and sodium polyacrylate.

[0056] In order to suppress the destruction or coalescence of oil droplets in the suspension during transfer, it is preferable to appropriately set the type and concentration of the dispersion stabilizer used in the aqueous phase. The content of the dispersion stabilizer in the aqueous phase is preferably 30% by mass or less, and more preferably 1 to 20% by mass.

[0057] The aqueous phase preferably further contains a second organic solvent. Depending on the type of the organic solvent (the first organic solvent) in the oil phase, it may rapidly move into the aqueous phase. Therefore, by mixing the aqueous phase containing the second organic solvent with the oil phase, it becomes possible to suppress the rapid movement of the first organic solvent in the oil phase into the aqueous phase, and resin beads with higher sphericity and a smoother surface can be produced. As the second organic solvent, the same solvents as those used in the oil phase (the first organic solvent) described above, including suitable ones, can be used. Note that the first organic solvent and the second organic solvent may be of the same type or different types.

[0058] In the suspension preparation step, an oil phase and an aqueous phase are mixed to prepare a suspension. To mix the oil phase and the aqueous phase, the oil phase may be added to the aqueous phase under stirring, or the aqueous phase may be added to the oil phase under stirring. The suspension may be in a state where oil droplets are dispersed in the aqueous phase (O / W), or after being in a state where water droplets are dispersed in the oil phase (W / O), it may be phase-inverted to a state where oil droplets are dispersed in the aqueous phase (O / W). If necessary, it is preferable to use an emulsifying device such as a disper or a homogenizer to adjust the particle size of the formed oil droplets. For example, by changing the rotation speed of the homogenizer to adjust the shear force, the particle size of the formed oil droplets can be easily adjusted. As a result, the particle size of the obtained resin beads can be appropriately adjusted to be within a desired range.

[0059] The liquid volume of the aqueous phase is preferably 3.0 times or less, more preferably 0.2 to 2.8 times, based on the mass of the liquid volume of the oil phase. By setting the liquid volume of the aqueous phase within the above range, rapid movement of the organic solvent in the oil droplets into the aqueous phase can be suppressed, and resin beads with higher sphericity and a smoother surface can be produced.

[0060] In the atomization step, the organic solvent is removed from the oil droplets in the suspension obtained in the suspension preparation step. Thereby, resin particles containing a filler and a cellulose derivative can be formed. As a method of removing the organic solvent from the oil droplets in the suspension and precipitating the cellulose derivative to form resin particles, for example, there is a method of heating the suspension to a temperature equal to or higher than the azeotropic point of the organic solvent and water to distill off the organic solvent. By further reducing the pressure, the organic solvent can be distilled off at a temperature lower than the azeotropic point. Further, it is preferable to adjust the degree of reduced pressure and distill off the organic solvent at a temperature closer to room temperature.

[0061] Further, it is also preferable to add water to the suspension, remove the organic solvent from the oil droplets in the suspension, and shrink the oil droplets to form resin particles. By adding water to the suspension, the organic solvent in the oil droplets moves into the aqueous phase, and cellulose derivative particles can be precipitated. Thereby, the oil droplets in the suspension can be rapidly shrunk, and resin particles and resin beads with higher sphericity and a smoother surface can be produced. The liquid volume of the water added to the suspension is preferably 0.1 times or more, more preferably 1 to 100 times, based on the mass of the liquid volume of the suspension. To remove the organic solvent from the oil droplets in the suspension and precipitate the cellulose derivative to form resin particles, a method of adding water to the suspension to shrink the oil droplets and a method of heating the suspension under reduced pressure to distill off the organic solvent may be combined. The atomization step is preferably carried out at a temperature as close to room temperature as possible.

[0062] In the hydrolysis step, the cellulose derivative in the resin particles formed in the atomization step is hydrolyzed (saponified) to form cellulose. Thereby, the desired resin beads in which the filler is encapsulated in the resin part containing the predetermined cellulose can be obtained.

[0063] Cellulose derivatives such as cellulose esters can be hydrolyzed under acidic conditions or alkaline conditions. When hydrolyzing under alkaline conditions, the pH is preferably 13.5 or less, more preferably 9.0 to 13.0. Further, the temperature during hydrolysis is preferably 70°C or less, more preferably 60°C or less, and particularly preferably 0 to 50°C. When the temperature during hydrolysis exceeds 70°C, hydrolysis tends to proceed excessively, and the crystallinity of cellulose may increase. As a result, the formed resin part may easily aggregate firmly. On the other hand, by setting the temperature during hydrolysis to 70°C or less, resin beads having a better touch and elongation to the skin, which can be suitably blended in cosmetics and the like, can be obtained. The degree (progress) of hydrolysis can be monitored at any time by infrared spectroscopy (IR). After confirming the degree (progress) of hydrolysis, an acid or an alkali may be added for neutralization.

[0064] After hydrolysis, for example, the produced resin beads are filtered and washed to remove unnecessary components. Then, if necessary, washing is repeated a plurality of times, followed by drying and crushing treatment, whereby the target resin beads can be obtained. After the crushing treatment, a combing treatment may be performed to remove coarse particles. It is sufficient to have a yield of 95% or more with 300 mesh (aperture of about 45 μm), preferably a yield of 97% or more, and more preferably a yield of 98% or more. If necessary, the particle size may be adjusted by classification or the like. Further, if necessary, silicone, fatty acid, fatty acid metal salt, amino acid, amino acid metal salt, oil and fat, and lipid may be used, and the resin particles may be surface-treated by a conventional method.

[0065] The resin beads of the present embodiment reduce the crystallinity of cellulose contained in the resin portion, thereby suppressing the hardening of particles due to strong crystals and relaxing the aggregability. Therefore, the resin beads of the present embodiment can effectively exhibit excellent touch and elongation to the skin, which are required for resin beads blended in cosmetics and the like. And by containing the resin beads of the present embodiment, various products such as cosmetics, skin medicines, paints, molded bodies, films, coating agents, and resin compositions, which are provided with excellent touch, elongation to the skin, and product stability, can be provided without using resin particles made of petroleum-derived synthetic materials.

Example

[0066] Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited to these examples. In addition, "parts" and "%" in the examples and comparative examples are based on mass unless otherwise specified.

[0067] <Manufacture of Resin Beads> (Example 1) 168.3 parts of cellulose acetate (trade name "CA-398-3", manufactured by Eastman Chemical Company, acetyl group content: 39.8%) was dissolved in 1125.4 parts of ethyl acetate (water solubility: 8 g / 100 g) to prepare a cellulose acetate solution. Further, 58 parts of cellulose acetate (trade name "CA-398-3", manufactured by Eastman Chemical Company, acetyl group content: 39.8%) was dissolved in 852 parts of ethyl acetate, and then 390 parts of barium sulfate (manufactured by Sakai Chemical Industry Co., Ltd., average particle diameter 0.5 μm) was mixed and dispersed to prepare a dispersion. Then, 150.5 parts of the prepared dispersion was mixed with the cellulose acetate solution to prepare an oil phase. Further, 40 parts of polyvinyl alcohol was dissolved in 760 parts of ion-exchanged water to prepare an aqueous phase. The prepared aqueous phase was added to the oil phase and mixed, and stirred using a dissolver to obtain a suspension in which oil droplets were uniformly dispersed.

[0068] While stirring the suspension obtained using a dissolver, 22,500 parts of ion-exchanged water were injected over 30 minutes to obtain a resin particle dispersion (resin bead dispersion). After filtering and washing the resin particles, they were peptized in ion-exchanged water and stirred. The resin particles obtained by filtering and washing were dispersed in ion-exchanged water. After heating to 40°C, caustic soda was added to adjust the pH to 13.5 or less, and a hydrolysis reaction was carried out. After the hydrolysis reaction was completed, it was neutralized with hydrochloric acid, and the product was filtered, washed, and then peptized in ion-exchanged water. After filtering, washing, and drying, it was crushed to obtain resin beads. The obtained resin beads were observed and image-analyzed using a scanning electron microscope (SEM), and it was confirmed that the filler (barium sulfate) was encapsulated in the resin part. Hereinafter, in the same manner, it was confirmed that the filler was encapsulated in the resin part. The peak intensity of the diffraction peak at a diffraction angle 2θ = 21.8° of the obtained resin beads (resin part) measured using an X-ray diffractometer (trade name "Miniflex600" (manufactured by Rigaku Corporation), X-ray source: Cu-Kα ray (40 kV, 15 mA)) was 9,901 cps. Also, the peak intensity of the diffraction peak at a diffraction angle 2θ = 15.0° was 7,684 cps, and the crystallinity of the resin beads (resin part) calculated by Equation (1) was 22.4%. Hereinafter, in the same manner, the crystallinity of the resin beads (resin part) was calculated.

[0069] (Example 2) 113.8 parts of cellulose acetate (trade name "CA-398-3", manufactured by Eastman Chemical Company, acetyl group content: 39.8%) was dissolved in 796.4 parts of ethyl acetate to prepare a cellulose acetate solution. Also, 58 parts of cellulose acetate (trade name "CA-398-3", manufactured by Eastman Chemical Company, acetyl group content: 39.8%) was dissolved in 852 parts of ethyl acetate, and then 390 parts of barium sulfate (manufactured by Sakai Chemical Industry Co., Ltd., average particle diameter 0.8 μm) was mixed and dispersed to prepare a dispersion. Then, 250.7 parts of the prepared dispersion was mixed with the cellulose acetate solution to prepare an oil phase. Also, 36 parts of polyvinyl alcohol was dissolved in 564 parts of ion-exchanged water to prepare an aqueous phase. The prepared oil phase was added to the aqueous phase and mixed, and stirred using a dissolver to obtain a suspension in which oil droplets were uniformly dispersed.

[0070] While stirring the suspension obtained using a dissolver, 20,000 parts of ion-exchanged water was injected over 30 minutes to obtain a resin particle dispersion (resin bead dispersion). After filtering and washing the resin particles, they were peptized in ion-exchanged water and stirred. The resin particles obtained by filtering and washing were dispersed in ion-exchanged water. After heating to 40°C, caustic soda was added to adjust the pH to 13.5 or less, and a hydrolysis reaction was carried out. After completion of the hydrolysis reaction, it was neutralized with hydrochloric acid, and the product was filtered, washed, and then peptized in ion-exchanged water. After filtering, washing, and drying, it was crushed to obtain resin beads. The crystallinity of the obtained resin beads (resin part) is shown in Table 1.

[0071] (Example 3) 25.4 parts of cellulose acetate (trade name "CA-398-3", manufactured by Eastman Chemical Company, acetyl group content: 39.8%) was dissolved in 206.5 parts of ethyl acetate to prepare a cellulose acetate solution. Also, 58 parts of cellulose acetate (trade name "CA-398-3", manufactured by Eastman Chemical Company, acetyl group content: 39.8%) was dissolved in 852 parts of ethyl acetate, and then 390 parts of barium sulfate (manufactured by Takehara Chemical Industry Co., Ltd., average particle diameter 1.0 μm) was mixed and dispersed to prepare a dispersion. Then, 351.3 parts of the prepared dispersion was mixed with the cellulose acetate solution to prepare an oil phase. Also, 18 parts of polyvinyl alcohol was dissolved in 282 parts of ion-exchanged water to prepare an aqueous phase. The prepared aqueous phase was added to and mixed with the oil phase, and stirred using a dissolver to obtain a suspension in which oil droplets were uniformly dispersed.

[0072] While stirring the suspension obtained using a dissolver, 9,000 parts of ion-exchanged water was injected over 30 minutes to obtain a resin particle dispersion (resin bead dispersion). After filtering and washing the resin particles, they were peptized in ion-exchanged water and stirred. The resin particles obtained by filtering and washing were dispersed in ion-exchanged water. After heating to 30°C, caustic soda was added to make the pH 13.5 or less, and a hydrolysis reaction was carried out. After the hydrolysis reaction was completed, it was neutralized with hydrochloric acid, the product was filtered and washed, and then peptized in ion-exchanged water. After filtering, washing, and drying, it was crushed to obtain resin beads. The crystallinity of the obtained resin beads (resin part) is shown in Table 1.

[0073] (Example 4) 168.3 parts of cellulose acetate (trade name "CA-398-3", manufactured by Eastman Chemical Company, acetyl group content: 39.8%) was dissolved in 1125.4 parts of ethyl acetate to prepare a cellulose acetate solution. Also, 58 parts of cellulose acetate (trade name "CA-398-3", manufactured by Eastman Chemical Company, acetyl group content: 39.8%) was dissolved in 852 parts of ethyl acetate, and then 390 parts of alumina (manufactured by Nikkoyo Metal Co., Ltd., average particle diameter 1.7 μm) was mixed and dispersed to prepare a dispersion. Then, 150.5 parts of the prepared dispersion was mixed with the cellulose acetate solution to prepare an oil phase. Also, 40 parts of polyvinyl alcohol was dissolved in 760 parts of ion-exchanged water to prepare an aqueous phase. The prepared aqueous phase was added to the oil phase and mixed, and stirred using a dissolver to obtain a suspension in which oil droplets were uniformly dispersed.

[0074] While stirring the suspension obtained using a dissolver, it was heated to 50°C, and while maintaining the temperature, the pressure was reduced to distill off ethyl acetate to obtain a resin particle dispersion (resin bead dispersion). After filtering and washing the resin particles, they were peptized in ion-exchanged water and stirred. The resin particles obtained by filtering and washing were dispersed in ion-exchanged water. After heating to 50°C, caustic soda was added to make the pH 13.5 or less, and a hydrolysis reaction was carried out. After the hydrolysis reaction was completed, it was neutralized with hydrochloric acid, the product was filtered and washed, and then peptized in ion-exchanged water. After filtering, washing, and drying, it was crushed to obtain resin beads. The crystallinity of the obtained resin beads (resin part) is shown in Table 1.

[0075] (Comparative Example 1) Commercially available cellulose fine particles (trade name "CELLULOBEADS D-10", manufactured by Daito Kasei Co., Ltd.) were used as the resin beads in Comparative Example 1. The crystallinity of the resin beads is shown in Table 1.

[0076] (Comparative Example 2) 250 parts of cellulose acetate (trade name "CA-398-3", manufactured by Eastman Chemical Company, acetyl group content: 39.8%) was dissolved in 2,250 parts of ethyl acetate to prepare an oil phase. Also, 50 parts of polyvinyl alcohol was dissolved in 1,200 parts of ion-exchanged water to prepare an aqueous phase. The prepared oil phase was added to the aqueous phase and mixed, and stirred using a dissolver to obtain a suspension in which oil droplets were uniformly dispersed.

[0077] While stirring the suspension obtained using the dissolver, 45,000 parts of ion-exchanged water was injected over 30 minutes to obtain a resin particle dispersion (resin bead dispersion). After filtering and washing the resin particles, peptization was carried out in ion-exchanged water and stirred. The resin particles obtained by filtering and washing were dispersed in ion-exchanged water. After heating to 50°C, caustic soda was added to make the pH 13.5 or less, and a hydrolysis reaction was carried out. After completion of the hydrolysis reaction, it was neutralized with hydrochloric acid, and the product was filtered and washed, and then peptized in ion-exchanged water. After filtering, washing, and drying, it was crushed to obtain resin beads. The crystallinity of the obtained resin beads is shown in Table 1.

[0078] (Evaluation of Resin Beads) (Average Particle Diameter) Using a Coulter counter (manufactured by Beckman Coulter), the average particle diameter of the resin beads (cumulative 50% particle diameter (median diameter; D 50 )) was measured. The results are shown in Table 1.

[0079] (Entrapment Rate) The filler inclusion rate was calculated according to the method shown below in accordance with JIS K 5101-15-2:2004. The sample was placed in a dryer maintained at a temperature of 105 ± 2 °C and dried for 2 hours, and then allowed to cool to room temperature in a desiccator. Approximately 2 g of the cooled sample was placed in a porcelain crucible that had been pre-weighed to a constant weight, and the mass was measured to the nearest 0.1 mg. Using a gas burner or an electric furnace, the sample was gradually heated so that it did not scatter. After nothing remained that would burn, it was strongly heated at 600 °C for about 1 hour. After the strongly heated porcelain crucible was placed in a desiccator and allowed to cool to room temperature, the mass was measured to the nearest 0.1 mg. The filler inclusion rate was calculated by dividing the mass measured after strong heating by the mass of the sample before heating. The results are shown in Table 1.

[0080] TIFF2025112837000001.tif63170

[0081] (Touch feeling) Regarding the touch feeling of the resin beads, a sensory evaluation was conducted by 10 panel tests. The resin beads were touched, and a comprehensive judgment was made on "smoothness" and "good elongation to the skin", and scored on a 5-point scale according to the evaluation criteria shown below, and the average score of 10 people was calculated. The results are shown in Table 2. 5: Good 4: Slightly good 3: Normal 2: Slightly bad 1: Bad

[0082] TIFF2025112837000002.tif55170

[0083] (Manufacture of cosmetics) (Cosmetics - 1) Cosmetic-1 was produced by mixing various components conventionally used as raw materials for cosmetics. Specifically, first, each silicone-treated powder (mica, talc, and fine particle titanium oxide) and each resin bead were blended in the blending amounts shown in Table 3 and mixed until uniform to obtain a powder mixture. Next, a mixture (other components) obtained by mixing petrolatum, squalane, and glyceryl trioctanoate was added to the powder mixture and mixed until uniform, and then filled into a container and press-molded as necessary to obtain Cosmetic-1.

[0084] TIFF2025112837000003.tif71170

[0085] (Cosmetic-2) Cosmetic-2, which is a sun cut emulsion, was produced by mixing various components conventionally used as raw materials for cosmetics. Specifically, first, silicone oil, an ultraviolet ray protector, an emulsifier, a dispersant, isotridecyl isononanoate, and each resin bead were blended in the blending amounts shown in Table 4 and mixed to prepare an oil phase component. Also, purified water, dipropylene glycol, sodium chloride, and sodium citrate were blended in the blending amounts shown in Table 4 and mixed to prepare an aqueous phase component. Next, the prepared aqueous phase component was added to the oil phase component with stirring for emulsification to obtain Cosmetic-2.

[0086] TIFF2025112837000004.tif90170

[0087] <Evaluation of Cosmetic-1> (Touch feeling, stretch on the skin) Regarding the touch feeling and stretch on the skin of Cosmetic-1, a sensory evaluation was conducted by a panel test of 10 people. The "goodness of touch feeling" and "stretch on the skin" were judged, scored on a scale of 5 points according to the evaluation criteria shown below, and the average score of 10 people was calculated. The results are shown in Table 5. 5: Good 4: Slightly good 3: Normal 2: Slightly bad 1: Bad

[0088] TIFF2025112837000005.tif57170

[0089] <Evaluation of Cosmetic - 2> (Touch feeling, elongation on the skin) For the touch feeling and elongation on the skin of Cosmetic - 2, a sensory evaluation was conducted by 10 panel tests. The "goodness of touch feeling" and "elongation on the skin" were judged, scored on a scale of 5 points according to the evaluation criteria shown below, and the average score of 10 people was calculated. The results are shown in Table 6. 5: Good 4: Slightly good 3: Normal 2: Slightly bad 1: Bad

[0090] TIFF2025112837000006.tif55170

[0091] As shown in Tables 5 and 6, it can be seen that by using the resin beads of the examples, a cosmetic excellent in touch feeling and elongation on the skin could be produced. Also, by using the resin beads of the examples, it was confirmed that excellent properties such as touch feeling and elongation can be imparted not only to cosmetics but also to various products such as external skin medicines, paints, molded articles, films, coating agents, and resin compositions.

Industrial Applicability

[0092] The resin beads of the present invention have properties equal to or better than those of resin beads formed of petroleum - derived synthetic materials. Therefore, by using the resin beads of the present invention, products such as cosmetics with a good touch feeling and good elongation on the skin can be provided without using resin beads formed of petroleum - derived synthetic materials. Accordingly, the resin beads of the present invention are useful as constituent materials for various products such as, for example, cosmetics, external skin agents, paints, molded articles, films, coating agents, and resin compositions.

Claims

1. A filler and a resin part encapsulating the filler, wherein the resin part is resin beads containing cellulose having a crystallinity of 50% or less calculated by the following formula (1). Crystallinity (%) = {(A - B) / A} × 100... (1) A: Peak intensity of the diffraction peak at diffraction angle 2θ = 21.8° ± 0.3° measured by X-ray diffraction using Cu-Kα line as the X-ray source B: Peak intensity of the diffraction peak at diffraction angle 2θ = 15.0° ± 0.3° measured by X-ray diffraction using Cu-Kα line as the X-ray source

2. The resin beads according to claim 1, wherein the cellulose is a hydrolyzate of a cellulose derivative.

3. The resin beads according to claim 2, wherein the cellulose derivative is a cellulose ester.

4. The resin beads according to claim 1, wherein the average particle diameter of the filler is 2 μm or less.

5. The resin beads according to claim 1, wherein the filler is at least one selected from the group consisting of inorganic particles and pigments.

6. The resin beads according to claim 1, wherein the filler is at least one selected from the group consisting of metal salts and metal oxides.

7. wherein the metal salt is at least one selected from the group consisting of barium sulfate and calcium carbonate, and the metal oxide is at least one selected from the group consisting of titanium oxide, zinc oxide, and aluminum oxide. The resin beads according to claim 6.

8. A method for producing the resin beads according to any one of claims 1 to 7, comprising mixing an oil phase containing a filler, a cellulose derivative, and an organic solvent having a solubility of 0.1 to 50.0 g in 100 g of water at 25°C for dissolving the cellulose derivative, and an aqueous phase containing a dispersion stabilizer to prepare a suspension containing oil droplets containing the filler, the cellulose derivative, and the organic solvent; removing the organic solvent from the oil droplets in the suspension to form resin particles containing the filler and the cellulose derivative; and hydrolyzing the cellulose derivative in the resin particles to form cellulose. A method for producing resin beads having the above steps.

9. The method for producing resin beads according to claim 8, wherein water is added to the suspension, the organic solvent is removed from the oil droplets in the suspension, and the oil droplets are shrunk to form the resin particles.

10. A product selected from the group consisting of cosmetics, skin drugs, paints, molded articles, films, coating agents, and resin compositions, containing the resin beads, wherein the resin beads are the resin beads according to any one of claims 1 to 7.

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