Biodegradable resin particles and use thereof

Abstract

The problem addressed is to provide biodegradable resin particles having high hydrophobicity, excellent spreadability on the skin, and excellent skin compatibility, a topical preparation containing the resin particles, a coating material containing the resin particles, a resin composition containing the resin particles, and an anti-blocking agent containing the resin particles. Provided as a solution are: biodegradable resin particles containing a polyhydroxyalkanoate resin that have a volume average primary particle size of 3 μm to 50 μm, a contact angle of 70° or more, a circularity of 0.90 to 1.00, and a BET specific surface area of 0.1 m2 / g to 10 m2 / g; a topical preparation containing the resin particles; a coating material containing the resin particles; a resin composition containing the resin particles; and an anti-blocking agent containing the resin particles.

Description

Biodegradable resin particles and their uses

[0001] The present invention relates to biodegradable resin particles and uses thereof.

[0002] Resin particles, taking advantage of their large specific surface area and particle structure, are used to modify and improve various materials. Major applications include compounding agents for cosmetics such as foundations, antiperspirants, and scrubs; matting agents for paints; rheology modifiers; antiblocking agents; slip-imparting agents; light diffusing agents; and various agents for medical diagnostic testing; as additives for molded articles such as automotive materials and building materials. Examples of resin particles include urethane, acrylic, silicone, and polyethylene. Meanwhile, with growing interest in environmental issues in recent years, there is a demand for the use of non-petroleum-derived materials and biodegradable materials in all fields where resins are used to reduce environmental impact. This demand is also seen in fields where resin particles are used, such as cosmetics and paints.

[0003] Known methods for producing resin particles using biodegradable materials include a pulverization method typified by freeze-pulverization (Patent Document 1), a solvent dissolution precipitation method in which a resin is dissolved in a solvent at a high temperature and then precipitated by cooling, or dissolved in a solvent and then precipitated by adding a poor solvent (Patent Document 2), and an emulsification method in which a polyhydric alcohol fatty acid ester and a water-soluble polymer are heated and stirred in an aqueous phase containing the mixture, followed by cooling (Patent Document 3).

[0004] JP 2017-2291 A JP 2016-102152 A JP 2022-161001 A

[0005] However, when used in external preparations such as cosmetics, the resin particles of Patent Document 1 have problems such as not being spherical and not being able to reduce the particle diameter, and further improvement in terms of spreadability on the skin is required. Furthermore, the resin particles obtained in Patent Document 2 are relatively spherical, but have the problem that the particle diameter does not reduce. Furthermore, the porous surface makes the particles brittle, resulting in low stability. The resin particles of Patent Document 3 are spherical, but have hydrophilic resin particle surfaces due to their water absorption properties, resulting in insufficient makeup wear in the field of cosmetics such as powder foundations.

[0006] The problem to be solved by the present invention is to provide biodegradable resin particles that are highly hydrophobic and have excellent spreadability and compatibility with the skin, a topical agent containing the resin particles, a coating material containing the resin particles, a resin composition containing the resin particles, and an anti-blocking agent containing the resin particles.

[0007] The present inventors have conducted extensive research to solve the above problems, and have found that specific biodegradable resin particles can solve the above problems, leading to the completion of the present invention. The present invention relates to the following items [1] to [8]. [Item 1] Biodegradable resin particles containing a polyhydroxyalkanoate resin, having a volume average primary particle diameter of 3 μm to 50 μm, a contact angle of 70° or more, a circularity of 0.90 to 1.00, and a BET specific surface area of ​​0.1 m ２ / g or more 10m ２ / g or less. [Item 2] The biodegradable resin particles according to Item 1, having a melting point of 150°C or higher. [Item 3] The biodegradable resin particles according to Item 1 or 2, having a total residual amount of unsaturated fatty acids of 10 ppm by mass or less. [Item 4] The biodegradable resin particles according to any one of Items 1 to 3, wherein the polyhydroxyalkanoate resin is poly(3-hydroxybutyrate-co-3-hydroxyvalerate) resin. [Item 5] An external preparation comprising the resin particles according to any one of Items 1 to 4. [Item 6] A coating material comprising the resin particles according to any one of Items 1 to 4. [Item 7] A resin composition comprising the resin particles according to any one of Items 1 to 4. [Item 8] An antiblocking agent comprising the resin particles according to any one of Items 1 to 4.

[0008] According to the present invention, it is possible to provide biodegradable resin particles that are highly hydrophobic and have excellent spreadability and compatibility with the skin, a topical agent containing the resin particles, a coating material containing the resin particles, a resin composition containing the resin particles, and an anti-blocking agent containing the resin particles.

[0009] The biodegradable resin particles of the present invention, the topical agent containing the resin particles, the coating material containing the resin particles, the resin composition containing the resin particles, and the antiblocking agent containing the resin particles will be described in detail below. In this specification, the numerical ranges can be any combination of the upper and lower limits described.

[0010] [Biodegradable Resin Particles] The biodegradable resin particles of the present invention are biodegradable resin particles containing a polyhydroxyalkanoate resin, and have a volume average primary particle diameter of 3 μm or more and 50 μm or less, a contact angle of 70° or more, a circularity of 0.90 or more and 1.00 or less, and a BET specific surface area of ​​0.1 m ２ / g or more 10m ２ / g or less. The biodegradable resin particles of the present invention can have a melting point of 150°C or higher. The biodegradable resin particles of the present invention can have a total residual amount of unsaturated fatty acids of 10 ppm by mass or less. The biodegradable resin particles of the present invention may be composed only of a polyhydroxyalkanoate resin, or may contain components other than the polyhydroxyalkanoate resin.

[0011] <Polyhydroxyalkanoate Resin> The polyhydroxyalkanoate resin contained in the biodegradable resin particles of the present invention is a biodegradable resin containing repeating units derived from an aliphatic hydroxycarboxylic acid, and may be a homopolymer or a copolymer. Examples of the aliphatic hydroxycarboxylic acid include one or more selected from the group consisting of 3-hydroxypropionate, 3-hydroxybutyrate, 3-hydroxyvalerate, 3-hydroxyhexanoate, 3-hydroxyheptanoate, 3-hydroxyoctanoate, 3-hydroxynonanoate, 3-hydroxydecanoate, 3-hydroxyundecanoate, 3-hydroxydodecanoate, 3-hydroxytetradecanoate, 3-hydroxyhexadecanoate, 3-hydroxyoctadecanoate, lactic acid, 4-hydroxybutyrate, 4-hydroxyvalerate, 5-hydroxyvalerate, and 6-hydroxyhexanoate.

[0012] The polyhydroxyalkanoate resin is represented by the formula (1): (In formula (1), R is -C ｎ H ２ｎ＋１ and n is an integer of 1 to 15.

[0013] In the present invention, the polyhydroxyalkanoate resin is preferably one containing 3-hydroxybutyrate units as the main component (for example, 50 mol % or more, preferably 80 mol % or more). For example, the main component is preferably one or more selected from the group consisting of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) resin, which is a copolymer of 3-hydroxybutyrate units and 3-hydroxyvalerate units, poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) resin, which is a copolymer of 3-hydroxybutyrate units and 3-hydroxyhexanoate units, and poly(3-hydroxybutyrate-co-3-hydroxyoctanoate) resin, which is a copolymer of 3-hydroxybutyrate units and 3-hydroxyoctanoate units, and more preferably poly(3-hydroxybutyrate-co-3-hydroxyvalerate) resin, which is the main component.

[0014] The polyhydroxyalkanoate resin may be a resin containing 3-hydroxybutyrate units as the main component (e.g., 50 mol % or more, preferably 80 mol % or more), such as poly(3-hydroxybutyrate-co-3-hydroxyvalerate) resin, poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) resin, or poly(3-hydroxybutyrate-co-3-hydroxyoctanoate) resin, preferably poly(3-hydroxybutyrate-co-3-hydroxyvalerate) resin, which has excellent biodegradability, particularly in water, and can address the recent problem of microplastics. The biodegradable resin particles of the present invention may contain one type of polyhydroxyalkanoate resin alone, or may contain two or more types of polyhydroxyalkanoate resins.

[0015] <Volume average primary particle diameter> The biodegradable resin particles of the present invention have a volume average primary particle diameter of 3 μm or more and 50 μm or less. The lower limit of the volume average primary particle diameter of the biodegradable resin particles can be preferably 5 μm or more, more preferably 6 μm or more, and the upper limit of the volume average primary particle diameter of the biodegradable resin particles can be preferably 45 μm or less, more preferably 35 μm or less, even more preferably 30 μm or less, even more preferably 25 μm or less, and particularly preferably 20 μm or less. The volume average primary particle diameter of the biodegradable resin particles of the present invention can be preferably in the range of 5 μm or more and 45 μm or less, more preferably 6 μm or more and 35 μm or less, even more preferably 6 μm or more and 30 μm or less, even more preferably 6 μm or more and 25 μm or less, and particularly preferably 6 μm or more and 20 μm or less. If the volume average primary particle diameter of the biodegradable resin particles is less than 3 μm, the particles may not spread well on the skin, and if the volume average primary particle diameter is more than 50 μm, the particles may feel unfavorable when applied to the skin as an external preparation, etc. The volume average primary particle diameter of the biodegradable resin particles is measured by the method described in the Examples below.

[0016] <Coefficient of Variation of Volume Average Primary Particle Diameter> The biodegradable resin particles of the present invention may have a coefficient of variation of the volume average primary particle diameter of 20% or more and 70% or less. The lower limit of the coefficient of variation of the volume average primary particle diameter of the biodegradable resin particles is preferably 25% or more, more preferably 30% or more, and the upper limit of the coefficient of variation of the volume average primary particle diameter of the biodegradable resin particles is preferably 65% ​​or less, more preferably 60% or less, even more preferably 55% or less, even more preferably 50% or less, and particularly preferably 45% or less. If the coefficient of variation of the volume average primary particle diameter of the biodegradable resin particles is less than 20%, the biodegradable resin particles may not be compatible with the skin. If the coefficient of variation of the volume average primary particle diameter of the biodegradable resin particles is more than 70%, the biodegradable resin particles may have a poor feel when used on the skin as an external preparation, etc. The coefficient of variation of the volume average primary particle diameter of the biodegradable resin particles is measured by the method described in the Examples below.

[0017] <Contact Angle> The biodegradable resin particles of the present invention have a contact angle of 70° or more. The lower limit of the contact angle of the biodegradable resin particles is preferably 75° or more, more preferably 80° or more, and even more preferably 85° or more. The upper limit of the contact angle of the biodegradable resin particles is not particularly limited, but can be, for example, 130° or less. The range of the contact angle of the biodegradable resin particles of the present invention is preferably 75° or more and 130° or less, more preferably 80° or more and 130° or less, even more preferably 80° or more and 120° or less, even more preferably 85° or more and 120° or less, and particularly preferably 90° or more and 120° or less. By setting the contact angle of the biodegradable resin particles to 70° or more, preferably 70° or more and 130° or less, an external preparation that is compatible with the skin and has excellent cosmetic wear can be obtained. In the present invention, the contact angle of the biodegradable resin particles is the contact angle with water. The contact angle of the biodegradable resin particles is measured by the method described in the Examples below.

[0018] <Circularity> The biodegradable resin particles of the present invention have a circularity of 0.90 or more and 1.00 or less. The lower limit of the circularity of the biodegradable resin particles is preferably 0.91 or more, more preferably 0.93 or more, and the upper limit of the circularity of the biodegradable resin particles is preferably 0.99 or less. The circularity of the biodegradable resin particles of the present invention can be in the range of 0.90 or more and 0.99 or less, 0.91 or more and 1.00 or less, 0.91 or more and 0.99 or less, 0.93 or more and 1.00 or less, or 0.93 or more and 0.99 or less. By setting the circularity to 0.90 or more and 1.00 or less, when an external preparation containing the biodegradable resin particles is prepared, the feel upon application is excellent. In the present invention, circularity is a measure of the sphericity of the resin particles, and a circularity of 1.00 can be said to be a true sphere. The circularity of the biodegradable resin particles is measured by the method described in the Examples below.

[0019] <BET specific surface area> The biodegradable resin particles of the present invention have a BET specific surface area of ​​0.1 m ２ / g or more 10m ２The lower limit of the BET specific surface area of ​​the biodegradable resin particles is preferably 0.2 m ２ / g or more, and the upper limit of the BET specific surface area is preferably 3 m ２ / g or less, more preferably 1m ２ The biodegradable resin particles of the present invention can have a BET specific surface area of ​​preferably 0.1 m / g or less. ２ / g or more 5m ２ / g or less, more preferably 0.2m ２ / g or more 3m ２ / g or less, more preferably 0.2m ２ / g or more 1m ２ / g or less. ２ If the specific surface area is less than 10 m / g, the particles will have a high specific gravity and will be prone to settling, which may reduce the handling properties when preparing the topical preparation. ２ If the BET specific surface area exceeds 1 / g, a large uneven structure will be formed on the surface or the particle will have a porous shape, which may reduce the particle strength and decrease the storage stability. The BET specific surface area of ​​the biodegradable resin particles is measured by the method described in the Examples below.

[0020] <Melting Point> The biodegradable resin particles of the present invention may have a melting point of 150°C or higher. The lower limit of the melting point of the biodegradable resin particles is preferably 155°C or higher, more preferably 160°C or higher, and the upper limit of the melting point of the biodegradable resin particles is preferably 260°C or lower, more preferably 250°C. A melting point below 150°C is undesirable because particles may aggregate due to local heat applied during the production of cosmetics such as powder foundation. On the other hand, a melting point above 260°C is undesirable because no significant effect is observed. The biodegradable resin particles of the present invention have a melting point range of, for example, 150°C or higher and 260°C or lower, preferably 155°C or higher and 260°C or lower, more preferably 160°C or higher and 250°C or lower.

[0021] <Total Residual Amount of Unsaturated Fatty Acids> The biodegradable resin particles of the present invention may have a total residual amount of unsaturated fatty acids of 10 ppm by mass or less, preferably 8 ppm by mass or less, more preferably 6 ppm by mass or less, and even more preferably 5 ppm by mass or less.

[0022] Polyhydroxyalkanoate resins are partially decomposed by heat or the like to produce unsaturated fatty acids. For example, unsaturated fatty acids such as crotonic acid are produced from the 3-hydroxybutyrate units in the polyhydroxyalkanoate resin; unsaturated fatty acids such as 2-pentenoic acid, 3-pentenoic acid, and 4-pentenoic acid are produced from the 3-hydroxyvalerate units; unsaturated fatty acids such as 2-hexenoic acid are produced from the 3-hydroxyhexanoate units; and unsaturated fatty acids such as 2-octenoic acid are produced from the 3-hydroxyoctanoate units. These unsaturated fatty acids are then contained in biodegradable resin particles containing a polyhydroxyalkanoate resin. These unsaturated fatty acids emit a distinctive odor, and therefore, when biodegradable resin particles are incorporated into topical preparations or the like, they may impart an unpleasant odor to the topical preparation, causing problems.

[0023] Components other than polyhydroxyalkanoate resins Examples of components other than polyhydroxyalkanoate resins that may be contained in the biodegradable resin particles of the present invention include components produced as by-products during resin production, various components used during resin particle production, and various components added to improve the properties of resin particles. Examples include surfactants, solvents, flowability modifiers, UV absorbers, light stabilizers, pigments (e.g., extender pigments, colored pigments, metallic pigments, mica powder pigments, etc.), dyes, moisturizers, resins other than polyhydroxyalkanoate resins, fragrances, clay minerals, preservatives / disinfectants, anti-inflammatory agents, antioxidants, pH adjusters (e.g., triethanolamine), and active pharmaceutical ingredients. The content of components produced as by-products during resin production (e.g., glycopeptides, proteins, nucleic acids, lipids, polysaccharides, hydrocarbons, and other microbial impurities) can be less than 0.1% by mass, preferably less than 0.09% by mass, and more preferably less than 0.08% by mass.

[0024] <Method for Producing Polyhydroxyalkanoate-Based Resin Particles> The method for producing the polyhydroxyalkanoate-based resin particles of the present invention is not particularly limited. Examples include the following production methods (I) to (II): (I) a production method (production method I) comprising the steps of heating and emulsifying / dispersing a polyhydroxyalkanoate-based resin in an aqueous dispersion medium containing an emulsifier and the like, cooling to obtain a polyhydroxyalkanoate-based resin dispersion, and then separating and drying the polyhydroxyalkanoate-based resin particles from the dispersion; (II) a production method (production method II) comprising the steps of mixing a polyhydroxyalkanoate-based resin, a dispersion stabilizer, a good solvent for the polyhydroxyalkanoate-based resin, and a poor solvent for the polyhydroxyalkanoate-based resin to obtain a polyhydroxyalkanoate-based resin dispersion, separating the polyhydroxyalkanoate-based resin particles from the polyhydroxyalkanoate-based resin dispersion, and drying the separated polyhydroxyalkanoate-based resin particles. In the present invention, it is preferable to produce biodegradable resin particles by Production Method I.

[0025] (Emulsifier) ​​The emulsifier used in Production Method I is a compound capable of emulsifying the polyhydroxyalkanoate resin to form a suspension. Examples of the emulsifier include one or more selected from the group consisting of nonionic surfactants, anionic surfactants, sugars, amino acids, water-soluble polymers, etc. In the present invention, it is preferable to use any of the following (i) to (iii) as the emulsifier: (i) a nonionic surfactant; (ii) a nonionic surfactant and an anionic surfactant; or (iii) a nonionic surfactant, an anionic surfactant, and a water-soluble polymer.

[0026] Examples of nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, polyoxysorbitan fatty acid esters, polyoxyethylene alkylamines, glycerin fatty acid esters, and polyoxyethylene polyoxypropylene glycols, and nonionic surfactants having a polyoxyalkylene structure are preferred.

[0027] A nonionic surfactant having a polyoxyalkylene structure has a structure represented by the formula (2) in the molecule: (In formula (2), A is an alkylene group having 2 to 6 carbon atoms, and multiple As may be the same or different, and m is the number of repeating units.)

[0028] Examples of nonionic surfactants having a polyoxyalkylene structure include polyoxyethylene alkyl ethers, polyoxypropylene alkyl ethers, polyoxybutylene alkyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, polyoxyethylene polyoxypropylene copolymers, polyoxyethylene alkylphenyl ethers, polyoxypropylene alkylphenyl ethers, polyoxyethylene polyoxypropylene alkylphenyl ethers, polyoxyethylene fatty acid esters, polyoxypropylene fatty acid esters, polyoxyethylene polyoxypropylene fatty acid esters, polyoxybutylene fatty acid esters, polyoxyethylene glycerin fatty acid esters, polyoxypropylene and at least one selected from the group consisting of propylene glycerin fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxypropylene sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxypropylene sorbitan fatty acid esters, polyoxyethylene castor oil derivatives, polyoxypropylene castor oil derivatives, polyoxyethylene alkylamines, polyoxypropylene alkylamines, polyoxyethylene polyoxypropylene alkylamines, polyoxyethylene alkylene amines, polyoxypropylene alkylene amines, polyoxyethylene polyoxypropylene alkylene amines, polyoxyethylene fatty acid amides, polyoxypropylene fatty acid amides, and the like.

[0029] In the present invention, the alkylene glycol is preferably one or more selected from the group consisting of polyoxyethylene alkyl ethers, polyoxypropylene alkyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, polyoxyethylene polyoxypropylene copolymers, polyoxyethylene alkyl phenyl ethers, polyoxypropylene alkyl phenyl ethers, polyoxyethylene polyoxypropylene alkyl phenyl ethers, polyoxyethylene fatty acid esters, polyoxypropylene fatty acid esters, and polyoxyethylene polyoxypropylene fatty acid esters, more preferably one or more selected from the group consisting of polyoxyethylene polyoxypropylene alkyl ethers, polyoxyethylene polyoxypropylene copolymers, polyoxyethylene polyoxypropylene alkyl phenyl ethers, and polyoxyethylene polyoxypropylene fatty acid esters, and even more preferably one or more polyoxyethylene polyoxypropylene copolymers.

[0030] The amount of the nonionic surfactant added is not particularly limited and can be, for example, 0.5 parts by mass or more, preferably 1 part by mass or more, and can be, for example, 25 parts by mass or less, preferably 20 parts by mass or less, relative to 100 parts by mass of water.

[0031] Examples of the anionic surfactant include one or more selected from the group consisting of sulfates (such as alkyl sulfates and polyoxyalkylene alkyl ether sulfates), sulfonates (such as alkylbenzenesulfonates and alkanesulfonates), and carboxylates (such as salts of fatty acids having 4 to 18 carbon atoms, alkenyl succinates, alkyl ether carboxylates, and polymeric polycarboxylates).

[0032] The amount of the anionic surfactant added is not particularly limited and can be, for example, 0.005 parts by mass or more, preferably 0.01 parts by mass or more, and can be, for example, 1.0 part by mass or less, preferably 0.5 part by mass or less, relative to 100 parts by mass of water.

[0033] Examples of the sugars include one or more selected from the group consisting of natural polymers such as starch, alginic acid, alginates, locust bean gum, guar gum, gum arabic, xanthan gum, agar, carrageenan, crystalline cellulose, and pectin; and semi-synthetic polymers such as hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, propylene glycol alginate, and cationic modified starch.

[0034] The amino acids include, for example, one or more selected from the group consisting of proteins such as glue, gelatin, casein, and albumin.

[0035] Examples of the water-soluble polymer include at least one selected from the group consisting of water-soluble polymers such as polyvinyl alcohol resins, polyethylene glycol, polyacrylamide, polyvinylpyrrolidone, polyacrylic acid, polyethyleneimine, anionic or cationic modified products thereof, hydrophobic modified products thereof, poly(meth)acrylic acid, polyvinylpyrrolidone, polyvinylamine, poly(anhydride)maleic acid, polystyrene sulfonic acid, copolymers of (meth)acrylic acid or maleic anhydride with vinyl monomers (e.g., (meth)acrylic acid esters, aromatic vinyl monomers (styrene, etc.), olefin monomers, etc.), modified polyesters (modified with succinic anhydride, maleic anhydride, polyethylene oxide, etc.), and polyoxyethylene polymers.

[0036] Examples of polyvinyl alcohol resins include partially saponified polyvinyl alcohol resins. The saponification degree of the polyvinyl alcohol resin is not particularly limited. For example, it can be 67 mol% or more, preferably 70 mol% or more, and for example, 80 mol% or less, preferably 75 mol% or less. If the saponification degree is outside the above range, the dispersion stability may decrease, resulting in an increase in aggregated particles and a decrease in circularity.

[0037] The amount of the water-soluble polymer added is not particularly limited and can be, for example, 0.05 parts by mass or more, preferably 0.1 parts by mass or more, and can be, for example, 5 parts by mass or less, preferably 3 parts by mass or less, relative to 100 parts by mass of water.

[0038] (Dispersion medium) Examples of the dispersion medium used in Production Method I include water, alcoholic solvents (methanol, ethanol, propanol, hexanol, ethylene glycol, diethylene glycol, 3-C １ ~C ５ Alkoxy-3-methyl-1-butanol and 3-C １ ~C ５ Examples of suitable solvents include alkoxy-3-methyl-1-butyl acetate, aliphatic hydrocarbon solvents (butane, pentane, hexane, cyclohexane, heptane, decane, hexadecane, etc.), aromatic hydrocarbon solvents (benzene, toluene, xylene, etc.), ester solvents (ethyl acetate, butyl acetate, etc.), ketone solvents (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.), ether solvents (ethylene glycol dimethyl ether, ethylene glycol monobutyl ether, etc.), and halogenated solvents (methyl chloride, methylene chloride, chloroform, carbon tetrachloride, etc.). In the present invention, preferred is one or more of water, alcohol, and ether solvents, and more preferred is water. Examples of water include ion-exchanged water, distilled water, pure water, tap water, industrial water, and groundwater.

[0039] (Dispersion stabilizer) In the step of obtaining a polyhydroxyalkanoate resin suspension in Production Method I, a dispersion stabilizer can be used. The dispersion stabilizer is not particularly limited as long as it functions as a dispersion stabilizer when the polyhydroxyalkanoate resin is emulsified and dispersed by heating and stirring in the presence of a dispersion medium, for example, by heating and stirring at a temperature of 110°C or higher and 180°C or lower. In the present invention, the dispersion stabilizer may, for example, be poorly water-soluble inorganic compound particles whose surfaces may be treated with a surface treatment agent such as a silane coupling agent.

[0040] The poorly water-soluble inorganic compound is a substance having a solubility in water of less than 2.0 g / L, preferably less than 1.0 g / L, more preferably less than 100 mg / L, and even more preferably less than 50 mg / L. Examples include one or more compounds selected from the group consisting of calcium carbonate, barium carbonate, magnesium carbonate, silica, alumina, titanium oxide, calcium sulfate, barium sulfate, magnesium sulfate, tricalcium phosphate (tricalcium phosphate), magnesium phosphate, aluminum phosphate, zinc phosphate, calcium pyrophosphate, magnesium pyrophosphate, aluminum pyrophosphate, zinc pyrophosphate, calcium metasilicate, etc. Among these, phosphates and / or carbonates, particularly tricalcium phosphate and / or calcium carbonate, are preferred because of their ease of removal after use.

[0041] The surface treatment agent for treating the surface of a poorly water-soluble inorganic compound is not particularly limited as long as it is a surface treatment agent that can impart hydrophobicity. Examples thereof include one or more selected from the group consisting of oils such as hydrocarbon oils, ester oils, and lanolin; silicones such as dimethylpolysiloxane, methylhydrogenpolysiloxane, and methylphenylpolysiloxane; fluorine compounds such as perfluoroalkyl group-containing esters, perfluoroalkylsilanes, perfluoropolyethers, and polymers having perfluoroalkyl groups; silane coupling agents such as 3-methacryloxypropyltrimethoxysilane and 3-glycidoxypropyltrimethoxysilane; titanium coupling agents such as isopropyl triisostearoyl titanate and isopropyl tris(dioctylpyrophosphate)titanate; metal soaps; fatty acids; amino acids such as acylglutamic acid; and lecithins such as hydrogenated egg yolk lecithin.

[0042] The amount of the dispersion medium used in the emulsification / dispersion step can be, for example, 100 parts by mass or more, and can be, for example, 2000 parts by mass or less, preferably 1500 parts by mass or less, and more preferably 1000 parts by mass or less, per 100 parts by mass of polyhydroxyalkanoate-based resin particles, from the viewpoint of sufficient stirring and mixing and productivity.

[0043] When a dispersion stabilizer is used in the method for producing polyhydroxyalkanoate-based resin particles according to Production Method I, the amount of the dispersion stabilizer used in the emulsification / dispersion step can be, for example, 5 parts by mass or more, preferably 10 parts by mass or more, per 100 parts by mass of polyhydroxyalkanoate-based resin particles, from the viewpoint of sufficient stirring and mixing and productivity, and can be, for example, 50 parts by mass or less, preferably 40 parts by mass or less, more preferably 35 parts by mass or less. In addition to the dispersion stabilizer, which is a poorly water-soluble inorganic compound, various surfactants can also be used in combination. The amount of surfactant added can be, for example, 0.01 parts by mass or more, for example, 0.5 parts by mass or less, per 100 parts by mass of water.

[0044] When the polyhydroxyalkanoate resin particles are heated and stirred, they can be stirred by means of a liquid phase stirring method using a stirring blade, a mixing method using a homogenizer, a mixing method using ultrasonic irradiation, etc. The stirring speed and time are not particularly limited as long as the polyhydroxyalkanoate resin is uniformly dispersed in the dispersion medium.

[0045] (Dispersion Stabilizer Removal Means) When a dispersion stabilizer is used in the production method I for producing polyhydroxyalkanoate resin particles, it is preferable to remove the dispersion stabilizer (a poorly water-soluble inorganic compound) before the step of separating the polyhydroxyalkanoate resin particles from the suspension. Examples of dispersion stabilizer removal methods include adding a reagent that decomposes and dissolves the dispersion stabilizer, or filtering out the dispersion stabilizer. In the present invention, it is preferable to remove the dispersion stabilizer by adding a reagent that decomposes and dissolves the dispersion stabilizer. As the dispersion stabilizer decomposing and dissolving reagent, from the viewpoint of suppressing hydrolysis of the polyhydroxyalkanoate resin and preventing a decrease in spreadability on the skin when added to a topical preparation, it is preferable to add, for example, 1.05 to 1.50 times, more preferably 1.05 to 1.20 times the required number of moles of acid (hydrochloric acid, sulfuric acid, nitric acid, etc.), stir at 40°C or less, and filter and wash within 24 hours, more preferably within 12 hours.

[0046] (Separation Means) In the step of separating polyhydroxyalkanoate-based resin particles from a suspension, a separation means for the polyhydroxyalkanoate-based resin particles includes a dispersion medium removal process. For example, a centrifugal dehydrator or a pressure dehydrator can be used for the dispersion medium removal process. In the separation means, a dispersion medium may be added to the polyhydroxyalkanoate-based resin suspension to remove the solvent. After the solvent removal process, the dispersion medium may be added again and the solvent removal process may be performed one or more times to wash the polyhydroxyalkanoate-based resin particles. In the separation means, the amount of dispersion medium added, the number of washing / dispersion medium removal water treatment steps, the dehydration conditions, etc. are not particularly limited and can be set appropriately.

[0047] (Drying Means) The drying means used in the step of drying the separated polyhydroxyalkanoate resin particles is not particularly limited. For example, a drying means using a dryer can be used. The dryer is not particularly limited, but examples include ovens, vacuum dryers, freeze dryers, reduced-pressure dryers, stationary shelf dryers, mobile shelf dryers, fluidized-bed dryers, rotary dryers, agitator dryers, and spray dryers. Among these, freeze dryers, tray-type vacuum dryers, and vacuum dryers incorporating agitator blades are preferred, and an appropriate drying device can be selected depending on the particle size, resin type, and the like. The drying conditions in the present invention are appropriately adjusted depending on the capacity and performance of the dryer used. For example, the degree of vacuum (relative to atmospheric pressure) can be −0.001 MPa to −0.1 MPa, the drying temperature can be 40°C to 95°C, and the drying time can be 4 hours to 30 hours (hr).

[0048] The dried polyhydroxyalkanoate-based resin particles are preferably cooled and then classified as necessary. The cooling method for the dried polyhydroxyalkanoate-based resin particles is not particularly limited. For example, the particles can be slowly cooled from the heating temperature during drying to a desired cooling temperature (e.g., 40°C or less, preferably room temperature (25°C ± 5°C)) at an arbitrary cooling rate (e.g., 0.5°C / min to 5°C / min). Cooling is preferably performed while stirring. The classification method for the dried polyhydroxyalkanoate-based resin particles is not particularly limited. Examples include air classification, airflow classification, and screen classification. Classification is preferably performed in an air atmosphere with a relative humidity of 30% or less, preferably 20% or less, so that the polyhydroxyalkanoate-based resin particles do not absorb moisture from the air. The obtained polyhydroxyalkanoate-based resin particles are preferably stored as a packaged item sealed in a moisture-resistant packaging material to prevent absorption of moisture from the air.

[0049] <Uses> The biodegradable resin particles of the present invention can be used in various applications. For example, they can be used as compounding agents for external preparations including various cosmetics such as foundations, antiperspirants, and scrubs, as well as various agents such as antiblocking agents, matting agents, rheology modifiers, slipping agents, light diffusing agents, antireflection agents, additives for sintering and molding fine ceramics, medical diagnostic testing agents, compounding agents for paints, fillers for adhesives, compounding agents for resin compositions, and additives for molded products such as automotive materials and building materials. Among these, the biodegradable resin particles of the present invention are preferably used as compounding agents for external preparations.

[0050] [External Preparation] The external preparation of the present invention is an external preparation containing the biodegradable resin particles of the present invention. Examples of external preparations include cosmetics, quasi-drugs, and the like. Examples of external preparations include makeup cosmetics such as face powders, face powders (loose powders, pressed powders, etc.), foundations (powder foundations, liquid foundations, emulsion foundations, etc.), lipsticks, lip balms, blushers, eyebrow cosmetics, and nail polish; cleansing cosmetics such as soaps, body shampoos, facial cleansing creams, scrub cleansers, and toothpaste; lotions such as pre-shave lotions and body lotions, external body preparations such as body powders and baby powders, skin care cosmetics such as lotions, creams, and emulsions (makeup emulsions); sunscreen cosmetics, tanning products, antiperspirants (liquid antiperspirants, solid antiperspirants, cream antiperspirants, etc.), packs, hair wash cosmetics, hair dyes, hair styling products, fragranced cosmetics, bath additives, and shaving creams. The topical preparation of the present invention may be one or more of these. Among these, from the viewpoint of reducing the environmental load, skin care cosmetics, cleansing cosmetics, sunscreen cosmetics, etc. are preferred, and powder foundations, emulsions, liquid foundations, scrub cleansers, etc. are more preferred.

[0051] The topical preparation of the present invention can be blended with commonly used main ingredients or additives according to the purpose, as long as the effects of the present invention are not impaired. Examples of such main ingredients or additives include one or more selected from the group consisting of water, alcohols having 6 or less carbon atoms (lower alcohols), oils and waxes, hydrocarbons, higher fatty acids, alcohols having 7 or more carbon atoms (higher alcohols), sterols, fatty acid esters, metal soaps, moisturizing agents, surfactants, polymeric compounds, coloring material raw materials, fragrances, clay minerals, antiseptics / bactericides, anti-inflammatory agents, antioxidants, ultraviolet absorbers, organic-inorganic composite particles, pH adjusters (such as triethanolamine), specially formulated additives, and active pharmaceutical ingredients.

[0052] In the topical preparation of the present invention, the content of the biodegradable resin particles of the present invention can be appropriately set depending on the type of topical preparation, etc., and is not particularly limited.From the viewpoint of achieving the desired effect, it is, for example, 0.1% by mass or more, preferably 0.5% by mass or more, more preferably 1% by mass or more, and from the viewpoint of improving production cost, stability, and feel, it is, for example, 50% by mass or less, preferably 40% by mass or less, more preferably 30% by mass or less.These upper and lower limits may be any combination of ranges.

[0053] [Coating Material] The coating material of the present invention is a coating material containing the biodegradable resin particles according to the present invention. In addition to the biodegradable resin particles of the present invention, the coating material may contain one or more binder resins, polymerization initiators, solvents, etc., as necessary. A suitable binder resin can be used taking into consideration the adhesion between the coating film formed from the coating material and the substrate, the environment in which the substrate on which the coating film is formed will be used, etc.

[0054] The binder resin is not particularly limited as long as it is a non-curable resin or a curable resin and has film-forming ability. Examples of the non-curable resin among the binder resins include polylactic acid, polyglycolic acid, polybutylene succinate, polybutylene succinate adipate, polybutylene adipate terephthalate, poly(ethylene succinate terephthalate), poly(butylene succinate terephthalate), poly(butylene adipate terephthalate), poly(ε-caprolactone), poly(β-propiolactone), polyamide 4, poly(3-hydroxybutyrate), poly(3-hydroxyvalerate), poly(3 Examples of the non-curable resin include one or more biodegradable resins such as poly(3-hydroxycaproate), poly(3-hydroxyheptanoate), poly(3-hydroxyoctanoate), poly(3-hydroxybutyrate.3-hydroxyhexanoate), poly(3-hydroxybutyrate.3-hydroxyvalerate), starch-based resins, cellulose-based resins, and glucosamine-based resins, as well as acrylic resins, alkyd resins, polyester resins, polyurethane resins, polyolefin resins, chlorinated polyolefin resins, and amorphous polyolefin resins. Examples of the non-curable resin include one or more resins dissolved in an organic solvent or water, and emulsion-type resins dispersed in an organic solvent or water.

[0055] The curable resin among the binder resins is not particularly limited, as long as it is a resin that can be cured via a crosslinking reaction by heat or active energy rays (ultraviolet rays, electron beams, etc.) and has film-forming ability. Examples of resins that can be cured by heat or active energy rays include resins having a carbon-carbon unsaturated bond. Examples include one or more of polyfunctional (meth)acrylate resins such as polyhydric alcohol polyfunctional (meth)acrylate; polyfunctional urethane (meth)acrylate resins synthesized from polyisocyanate, polyol, and hydroxy group-containing (meth)acrylic acid ester; and epoxy (meth)acrylate resins. Among these, one or more of polyfunctional (meth)acrylate resins and urethane (meth)acrylate resins are preferred, and polyhydric alcohol polyfunctional (meth)acrylate resins having three or more (meth)acryloyl groups per molecule are more preferred. Specific examples of polyhydric alcohol polyfunctional (meth)acrylate resins having three or more (meth)acryloyl groups in one molecule include one or more of trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, 1,2,4-cyclohexane tetra(meth)acrylate, pentaglycerol triacrylate, pentaerythritol tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol triacrylate, dipentaerythritol pentaacrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tripentaerythritol triacrylate, and tripentaerythritol hexaacrylate.

[0056] When a curable resin is used as the binder resin, a polymerization initiator can be used in combination. The polymerization initiator is not particularly limited as long as it can generate an active species by heating or irradiation with active energy rays and initiate curing of the curable resin. Examples of the polymerization initiator include one or more of acetophenones, benzoins, benzophenones, phosphine oxides, ketals, α-hydroxyalkylphenones, α-aminoalkylphenones, anthraquinones, thioxanthones, azo compounds, peroxides, 2,3-dialkyldione compounds, disulfide compounds, fluoroamine compounds, aromatic sulfonium compounds, onium salts, borate salts, active halogen compounds, and α-acyloxime esters.

[0057] The solvent is not particularly limited as long as it can dissolve or disperse the binder resin or curable resin. When the coating material is an oil-based coating material, examples of the solvent include one or more of hydrocarbon solvents such as toluene and xylene; ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone; ester solvents such as ethyl acetate and butyl acetate; and ether solvents such as dioxane, ethylene glycol diethyl ether and ethylene glycol monobutyl ether. When the coating material is a water-based coating material, examples of the solvent include one or more of water and water-soluble organic solvents (alcohols, etc.).

[0058] The coating material of the present invention may contain, as necessary, one or more of a coating surface conditioner, a flowability conditioner, an ultraviolet absorber, a light stabilizer, a curing catalyst, an extender pigment, a coloring pigment, a metal pigment, a mica powder pigment, a dye, and the like.

[0059] The content of each component constituting the coating material of the present invention can be appropriately determined depending on the film thickness of the coating film to be formed, the average particle size of the biodegradable resin particles, the coating method, etc. The content of the biodegradable resin particles in the coating material of the present invention can be, for example, 1% by mass to 50% by mass, preferably 3% by mass to 50% by mass, more preferably 3% by mass to 45% by mass, and even more preferably 5% by mass to 40% by mass, based on the total content of the binder resin solids and the biodegradable resin particles being 100% by mass. The content of the solvent in the coating material of the present invention can be, for example, 10% by mass to 80% by mass, preferably 20% by mass to 60% by mass, based on the total amount of the coating material being 100% by mass.

[0060] The material constituting the substrate to which the coating material of the present invention is applied is not particularly limited. Examples include one or more of metal, glass, ceramic, wood, paper, plastic, and composite materials composed of one or more of these. The coating material of the present invention can be used to coat transparent substrates such as polyester resins (e.g., polyethylene terephthalate), polycarbonate resins, and (meth)acrylic resins.

[0061] The method for forming a coating film using the coating material of the present invention is not particularly limited. Examples include one or more of a spray method, a roll method, a brush coating method, a reverse roll coating method, a gravure coating method, a die coating method, and a comma coating method. When forming a coating film using the coating material of the present invention, the coating material is applied to an arbitrary coating surface to form a coating film, and then coated to form a coating film, which is dried and then cured as necessary, thereby forming a cross-linked coating film.

[0062] [Resin Composition] The resin composition of the present invention is a resin composition containing the biodegradable resin particles according to the present invention. The resin composition may contain a base resin in addition to the biodegradable resin particles of the present invention. Examples of the base resin include biodegradable resins such as polylactic acid, polyglycolic acid, polybutylene succinate, polybutylene succinate adipate, polybutylene adipate terephthalate, poly(ethylene succinate terephthalate), poly(butylene succinate terephthalate), poly(butylene adipate terephthalate), poly(ε-caprolactone), poly(β-propiolactone), polyamide 4, poly(3-hydroxybutyrate), poly(3-hydroxyvalerate), poly(3-hydroxycaproate), poly(3-hydroxyheptanoate), poly(3-hydroxyoctanoate), poly(3-hydroxybutyrate-3-hydroxyhexanoate), poly(3-hydroxybutyrate-3-hydroxyvalerate), starch-based resins, cellulose-based resins, and glucosamine-based resins; Examples of the thermoplastic resin include one or more thermoplastic resins such as polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polyamide 6, polyamide 66, polyamide 12, ABS resin (acrylonitrile-butadiene-styrene copolymer resin), AS resin (acrylonitrile-styrene copolymer resin), polyethylene, polypropylene, polyacetal, polyamideimide, polyethersulfone, polyimide, polyphenylene oxide, polyphenylene sulfide, polystyrene, thermoplastic polyurethane elastomer, thermoplastic polyester elastomer, thermoplastic polyamide elastomer, polyvinyl chloride, polyvinylidene fluoride, ethylene tetrafluoroethylene copolymer (ETFE resin), tetrafluoroethylene perfluoroalkyl vinyl ether copolymer (PFA resin), and polyether ketone.

[0063] The resin composition of the present invention may contain one or more additives as needed, such as reinforcing fibers (glass fibers, carbon fibers, etc.), flame retardants, flowability modifiers, ultraviolet absorbers, heat stabilizers, light stabilizers, lubricants, extender pigments, coloring pigments, metallic pigments, and dyes.

[0064] The content of each component constituting the resin composition of the present invention can be appropriately determined depending on the shape of the molded article formed from the resin composition, the average particle size of the biodegradable resin particles, the molding method, etc. The content of the biodegradable resin particles in the resin composition of the present invention can be, for example, 0.1% by mass or more and 70% by mass or less, preferably 0.5% by mass or more and 50% by mass or less, and more preferably 1% by mass or more and 30% by mass or less, when the total content of the base resin and the biodegradable resin particles is 100% by mass.

[0065] The method for producing the resin composition of the present invention is not particularly limited. The resin composition can be produced by mixing a base resin and biodegradable resin particles by a mechanical grinding and mixing method, etc. Examples of the mechanical grinding and mixing method include a method in which the base resin and biodegradable resin particles are stirred and mixed using a mixing device such as a Henschel mixer, a V-type mixer, a Turbula mixer, a hybridizer, or a rocking mixer.

[0066] The resin composition of the present invention can be used as a molding material for obtaining a molded article. The molding method for the molded article is not particularly limited. For example, the resin composition of the present invention can be kneaded to obtain pellets, and then the pellets can be molded by a molding method such as extrusion molding, injection molding, or blow molding. Examples of molded articles obtained by molding the resin composition of the present invention include automotive materials, building materials, and packaging materials.

[0067] [Anti-blocking agent] The anti-blocking agent of the present invention is an anti-blocking agent containing the biodegradable resin particles of the present invention. The anti-blocking agent of the present invention is contained in a resin film and can be used to impart irregularities to the surface of a resin film in order to prevent blocking, which occurs when the resin film is wound up, causing contact between adjacent resin film surfaces to adhere to each other and prevent separation.

[0068] The antiblocking agent of the present invention may contain one or more of an antioxidant, a flowability modifier, a light stabilizer, a color pigment, etc., as needed.

[0069] The content of the biodegradable resin particles in the antiblocking agent of the present invention can be, for example, 70% by mass or more and 100% by mass or less, preferably 80% by mass or more and 100% by mass or less, and more preferably 90% by mass or more and 100% by mass or less, where the total amount of the antiblocking agent is 100% by mass.

[0070] Examples of resin films for which the antiblocking agent of the present invention can be used include polylactic acid, polyglycolic acid, polybutylene succinate, polybutylene succinate adipate, polybutylene adipate terephthalate, poly(ethylene succinate terephthalate), poly(butylene succinate terephthalate), poly(butylene adipate terephthalate), poly(ε-caprolactone), poly(β-propiolactone), polyamide 4, poly(3-hydroxybutyrate), poly(3-hydroxyvalerate), poly(3-hydroxycaproate), poly(3-hydroxyheptanoate), poly(3-hydroxyoctanoate), poly(3-hydroxybutyrate.3-hydroxyhexanoate), and poly(3-hydroxybutyrate.3-hydroxyhexanoate). Examples of suitable anti-blocking agents include biodegradable resins such as polyaniline sivalate, starch-based resins, cellulose-based resins, and glucosamine-based resins; polyester-based resins such as polyethylene terephthalate and polyethylene naphthalate; polyolefin-based resins such as polyethylene-based resins and polypropylene-based resins; (meth)acrylic resins; polystyrene-based resins; polyethersulfone-based resins; polyurethane-based resins; polycarbonate-based resins; polysulfone-based resins; polyether-based resins; polymethylpentene-based resins; polyetherketone-based resins; (meth)acrylonitrile-based resins; norbornene-based resins; amorphous polyolefin-based resins; polyamide resins; polyimide resins; triacetyl cellulose resins; resin compositions containing one or more of these resins; and laminates composed of one or more of these resins. The anti-blocking agent of the present invention can be used when kneading with these resins and forming them into a film to form a resin film.

[0071] The content of the biodegradable resin particles of the present invention in the resin film is not particularly limited. It can be appropriately determined depending on the thickness of the film to be formed, the average particle size of the biodegradable resin particles, the surface roughness of the film to be formed, the film forming method, etc. For example, the content can be, for example, 0.01% by mass or more and 10% by mass or less, preferably 0.01% by mass or more and 5% by mass or less, more preferably 0.01% by mass or more and 3% by mass or less, and even more preferably 0.01% by mass or more and 1% by mass or less, based on the total amount of the resin film being 100% by mass.

[0072] The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited thereto. Unless otherwise specified, "parts" means "parts by mass" and "%" means "% by mass".

[0073] [Measurement Methods, etc.] <Volume Average Primary Particle Diameter> The volume average primary particle diameter of biodegradable resin particles was measured using a precision particle size distribution analyzer (Beckman Coulter's "Multisizer 4e"). Measurement of the volume average primary particle diameter of biodegradable resin particles was performed using an aperture calibrated according to the user's manual, appropriately selected depending on the size of the particles to be measured. The measurement sample was a dispersion prepared by dispersing 0.1 g of biodegradable resin particles in 10 ml of a 0.1% by mass aqueous solution of a nonionic surfactant using a touch mixer (Yamato Scientific's "TOUCHMIXER MT-31") and an ultrasonic cleaner (Velvoclear's "ULTRASONIC CLEANER VS-150") The contents of the beaker were gently stirred during measurement to prevent air bubbles from being introduced, and the particle diameters of 100,000 biodegradable resin particles were measured, and the standard deviation of the particle size distribution was calculated. The volume average primary particle diameter of the resin particles is the arithmetic mean in the particle size distribution based on the volume of 100,000 particles. The coefficient of variation (CV value) of the particle diameter of the resin particles is calculated by the following formula.

[0074] <Contact Angle> The contact angle of the biodegradable resin particles was measured as follows: 0.35 g of biodegradable resin particles were placed in a tablet molding machine and subjected to a pressure of 300 kgf / cm ２The tablets were prepared by molding for 1 minute and used as samples for contact angle measurement. The obtained samples were left to stand for 16 hours or more in an environment of 20 ° C. ± 2 ° C. and 65% ± 5% humidity to condition. Using the conditioned samples, distilled water was used as the dropping liquid, and the liquid volume was 1 μL, and the contact angle was measured by the sessile drop method in an environment of 20 ° C. ± 2 ° C. and 65% ± 5% humidity using a solid-liquid interface analyzer (Kyowa Interface Science Co., Ltd. "Drop Master 300"). The contact angle was measured immediately after dropping. The contact angle was calculated using the θ / 2 method using the software "FAMAS" included with the device. The number of tests was 10, and the average value was taken as the contact angle.

[0075] <Circularity> The circularity of the biodegradable resin particles was measured using a flow particle image analyzer (Sysmex Corporation, "FPIA-3000S"). 0.05 g of a surfactant (sodium alkylbenzene sulfonate) was added to 20 mL of ion-exchanged water as a dispersant to obtain a surfactant aqueous solution. 0.2 g of biodegradable resin particles was added to the obtained surfactant aqueous solution, and an ultrasonic disperser (BRANSON Corporation, "BRANSON SONIFIER 450") was used to irradiate the resin particles with ultrasonic waves at an output of 400 W and a frequency of 20 kHz for 5 minutes to disperse the resin particles in the surfactant aqueous solution, thereby obtaining a dispersion for measurement. Using the obtained dispersion for measurement, a flow particle image analyzer equipped with a standard objective lens (10x magnification) was used to measure the circularity under the following measurement conditions, using a particle sheath (Sysmex Corporation, "PSE-900A") as the sheath liquid. Measurement mode: HPF measurement mode Particle size measurement range: 1 μm to 100 μm Particle circularity measurement range: 0.5 to 1.0 Number of particles measured: 1,000 Before starting the measurement, a suspension of standard polymer particles ("5200A" manufactured by Thermo Fisher Scientific, Inc. (standard polystyrene particles diluted with ion-exchanged water)) was used, and automatic focus adjustment of the flow particle image analyzer was performed. Note that the circularity is the value obtained by dividing the perimeter calculated from the diameter of a perfect circle having the same projected area as the image of the resin particle by the perimeter of the image of the resin particle.

[0076] <BET Specific Surface Area> The BET specific surface area of ​​the biodegradable resin particles was measured by the BET method (nitrogen adsorption method) described in ISO 9277 1st Edition and JIS Z 8830: 2001. The biodegradable resin particles were measured using an automatic specific surface area / pore size distribution analyzer (Shimadzu Corporation's "Tristar II 3020"), with nitrogen as the adsorbate and an adsorbate cross-sectional area of ​​0.162 nm. ２ The BET nitrogen adsorption isotherm was measured by the constant volume method under the conditions, and the specific surface area was calculated from the nitrogen adsorption amount using the BET multipoint method. When measuring the BET specific surface area, the biodegradable resin particles were pretreated by heated gas purging. The pretreatment method involved heating a container containing the biodegradable resin particles at 65°C while purging with nitrogen for 15 minutes, allowing the container to cool to room temperature, and then vacuum degassing the container for 90 minutes while heating it at 65°C.

[0077] <Melting Point> The melting point of the resin particles was measured according to the method described in JIS K7121:1987 and JIS K7121:2012. However, the sampling method and temperature conditions were as follows. 5.5±0.5 mg of the sample was packed into an aluminum measurement container so that there were no gaps at the bottom, and then the aluminum lid was placed on top. Differential scanning calorimetry was then performed using a Hitachi High-Tech Science DSC7000X, AS-3 differential scanning calorimeter. The sample was heated and cooled in the following steps under a nitrogen gas flow rate of 20 mL / min to obtain a DSC curve: (Step 1) Heat from -40°C to 185°C (first heating), and maintained for 10 minutes. (Step 2) Cool from 185°C to -40°C (cooling), and maintained for 10 minutes. (Step 3) Heat from -40°C to 185°C (second heating). All heating and cooling was performed at a rate of 10°C / min. Alumina was used as the reference material. Using the analysis software provided with the device, the top temperature of the melting peak observed during the second heating process was read and used as the melting point.

[0078] <Residual Amount of Unsaturated Fatty Acids> Quantitative analysis of the residual amount of unsaturated fatty acids was performed as follows. (Extraction Pretreatment Method) Approximately 1 g of biodegradable resin particles was precisely weighed into a centrifuge tube, 5 mL of methanol was added, and the mixture was mixed. Ultrasonic extraction was performed for 15 minutes, and the mixture was mixed well again. The mixture was centrifuged at 3,500 rpm for 30 minutes, and the supernatant was filtered through a non-aqueous 0.2 μm Chromatographic Disk 13N (manufactured by GL Sciences) to obtain a test solution, which was then subjected to UHPLC (ultra-high performance liquid chromatography) measurement.

[0079] (Measurement Method) The conditions for UHPLC measurement of the test solution were as follows. Unsaturated fatty acids were quantified using standard peak area values ​​obtained from chromatograms using standard solutions. A calibration curve prepared on a Shimadzu LabSolutions chromatographic workstation was used for quantification. The concentration of each unsaturated fatty acid in the test solution was determined from this calibration curve, and the content of each unsaturated fatty acid (remaining amount of unsaturated fatty acid) was calculated from the obtained results. Amount of unsaturated fatty acid (mg / kg) = Measured value (μg / mL) × Amount of methanol extracted (mL) ÷ Sample mass (g)

[0080] (UHPLC measurement conditions) Apparatus: Shimadzu Corporation "NexeraX2" ultra high performance liquid chromatograph Column: Kinetex 1.7 μm C18 100A (2.1 mm I.D. × 50 mmL) Column temperature: 40° C. Pump temperature: room temperature (23° C.) Mobile phase: (A: 0.05% trifluoroacetic acid (TFA) / B: acetonitrile) Mobile phase conditions: (0 → 0.5 min = B ｃｏｎｃ． 90%, 0.5→0.51min=B ｃｏｎｃ． 90%→80%, 0.51→2min=B ｃｏｎｃ． 80%, 2→2.5min=B ｃｏｎｃ． 80%→20%, 2.5→3min=B ｃｏｎｃ． 20%, 3→3.5min=B ｃｏｎｃ． 20%→90%, 3.5→5min=B ｃｏｎｃ． 90%) Flow rate: 0.6 mL / min Measurement time: 5 min Injection volume: 1 μL Detector: PDA = 210 nm (crotonic acid, 2-pentenoic acid), 200 nm (4-pentenoic acid)

[0081] (Method of preparing standard solutions) Using the automatic dilution function of the autosampler of a Shimadzu Corporation "NexeraX2" ultra-high performance liquid chromatograph, the 1,000 mg / L standard solution was diluted 10-fold with methanol to prepare a 100 mg / L standard solution, and 20-fold with methanol to prepare a 50 mg / L standard solution. The 100 mg / L standard solution was further diluted 5-fold to prepare a 20 mg / L standard solution. The 50 mg / L standard solution was diluted 5-fold to prepare a 10 mg / L standard solution. The 20 mg / L standard solution was diluted 5-fold to prepare a 4 mg / L standard solution. The 10 mg / L standard solution was diluted 10-fold to prepare a 1 mg / L standard solution. The 1 mg / L standard solution was diluted 5-fold to prepare a 0.2 mg / L standard solution. 4-Pentenoic acid was also measured by the following method.

[0082] <Residual Amounts of Crotonic Acid, 2-Pentenoic Acid, and 4-Pentenoic Acid> Quantitative analysis of the residual amounts of crotonic acid, 2-pentenoic acid, and 4-pentenoic acid among unsaturated fatty acids was carried out as follows.

[0083] (Extraction Pretreatment Method) Approximately 1 g of biodegradable resin particles was weighed, immersed in 10 mL of acetone, and subjected to ultrasonic extraction for 30 minutes. 1 mL of the extract (supernatant) was collected in a measurement vial, and 0.5 mL of bis(trimethylsilyl)trifluoroacetamide (BSTFA) was added, gently shaken, and allowed to stand for 1 hour or more for derivatization (trimethylsilylation) to obtain a test solution, which was then measured using a gas chromatograph-mass spectrometer (GC-MS).

[0084] (Measurement Method) The conditions for GC-MS measurement of the test solution were as shown below. Each acid was quantified using the standard peak area value obtained from a chromatogram using a standard solution. A calibration curve prepared using the standard solution was used for the quantification. The concentration of each acid in the test solution was determined from this calibration curve, and the content of each acid (amount of crotonic acid remaining, amount of 2-pentenoic acid remaining, or amount of 4-pentenoic acid remaining) was calculated from the obtained results. Amount of each acid remaining (μg / g) = concentration of each acid in the test solution (μg / mL) × amount extracted (mL) ÷ mass of sample (g)

[0085] (GC-MS measurement conditions) Apparatus: Agilent Technologies 7890A GC / 5975C MSD system Column: Agilent J&W DB-5ms, 30 m x 0.25 mm i.d. Film thickness: 0.25 μm Injection port temperature: 250°C Carrier gas: Helium 1 ml / min Split ratio: 10:1 Oven temperature: 50°C (1 min) - 10°C / min - 300°C (5 min) Injection volume: 1 μL Ionization method: Electron impact ionization (EI method: 70 eV) Measurement mode: Selected ion monitoring (SIM) mode Monitor ion: Quantitative ion m / z 157 (4-pentenoic acid TMS derivative)

[0086] (Method for preparing standard solutions) 0.1 g of 4-pentenoic acid was placed in a 10 mL volumetric flask and adjusted to volume with acetone to prepare a 1000 μg / mL standard stock solution. This was diluted with acetone to prepare standard solutions of 500, 100, 50, 10, 5, 1, and 0.5 μg / mL. Derivatization was performed in the same manner as for the sample extract. Standard solutions of crotonic acid and 2-pentenoic acid were also prepared in the same manner as for 4-pentenoic acid.

[0087] [Production of Resin Pellets] <Production Example 1> Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) resin raw material powder ("ENMAT Y1000" manufactured by Tenan Biotechnology Co., Ltd.) was continuously fed at 15 kg / h into a 26 mm twin-screw extruder ("TEM-26" manufactured by Toshiba Machine Co., Ltd.), extruded through a φ5 × 5-hole strand die attached to the tip of the extruder, and the strand was cooled and pelletized in a pelletizer to obtain poly(3-hydroxybutyrate-co-3-hydroxyvalerate) resin raw material pellets. The resin temperature at the die outlet was 188°C.

[0088] [Examples and Comparative Examples] <<Preparation of Biodegradable Resin Particles>> <Example 1> 750 parts by mass of ion-exchanged water and 50 parts by mass of a nonionic surfactant (polyethylene oxide-polypropylene oxide copolymer; molecular weight approximately 10,000) were placed in a 2-L autoclave equipped with a stirring blade and a thermometer, and the mixture was stirred at 200 rpm for 2 hours to prepare an aqueous phase. 200 parts by mass of the poly(3-hydroxybutyrate-co-3-hydroxyvalerate) resin raw material pellets obtained in Production Example 1 were added thereto, and the mixture was heated to an internal temperature of 170°C while stirring at 300 rpm. After reaching 170°C, the mixture was emulsified for 30 minutes. The mixture was then cooled to 40°C while maintaining the rotation speed at 300 rpm to obtain a suspension. The resulting suspension was then filtered, washed, dried, and classified to obtain poly(3-hydroxybutyrate-co-3-hydroxyvalerate) resin particles. The resulting resin particles had a volume average primary particle diameter of 15.6 μm, a CV value of 61.2%, a contact angle of 100°, a circularity of 0.98, and a BET specific surface area of ​​0.66 m ２ / g, melting point 170°C, no residual crotonic acid, residual 2-pentenoic acid, or residual 4-pentenoic acid was detected, and it was confirmed that the total amount of residual unsaturated fatty acids was 10 ppm by mass or less.

[0089] Example 2 620 parts by mass of ion-exchanged water, 60 parts by mass of a nonionic surfactant (polyethylene oxide-polypropylene oxide copolymer; molecular weight approximately 10,000), and 5 parts by mass of polyvinyl alcohol (saponification degree: 72.9 mol %, viscosity of a 4 wt % aqueous solution at 20°C: 7.3 mPa s) were placed in a 2-L autoclave equipped with a stirring blade and a thermometer, and the mixture was stirred at 200 rpm for 2 hours. Thereafter, 0.56 parts by mass of dipotassium alkenylsuccinate, 240 parts by mass of a 10% aqueous solution of calcium phosphate tribasic (manufactured by Taihei Chemical Industry Co., Ltd., "TCP-10U"), and 100 parts by mass of the poly(3-hydroxybutyrate-co-3-hydroxyvalerate) resin raw material pellets obtained in Production Example 1 were added, and the mixture was heated to an internal temperature of 165°C while stirring at 500 rpm. After the temperature reached 165°C, the mixture was emulsified for 90 minutes. Thereafter, the mixture was cooled to 40°C while maintaining the rotation speed at 500 rpm, yielding a suspension. Next, 100 parts by mass of 20% hydrochloric acid was added to the resulting suspension to decompose the tribasic calcium phosphate, followed by filtration, washing, drying, and classification to yield poly(3-hydroxybutyrate-co-3-hydroxyvalerate) resin particles. The resulting resin particles had a volume-average primary particle diameter of 5.1 μm, a CV value of 34.5%, a contact angle of 91°, a circularity of 0.98, and a BET specific surface area of ​​0.90 m. ２ / g, melting point 170°C, no residual crotonic acid, residual 2-pentenoic acid, or residual 4-pentenoic acid was detected, and it was confirmed that the total amount of residual unsaturated fatty acids was 10 ppm by mass or less.

[0090] Example 3 Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) resin particles were obtained in the same manner as in Example 2, except that polyvinyl alcohol having a saponification degree of 87.3 mol % and a viscosity of a 4 wt % aqueous solution at 20°C of 5.3 mPa s was used. The obtained resin particles had a volume average primary particle diameter of 4.8 μm, a CV value of 46.2%, a contact angle of 78°, a circularity of 0.94, and a BET specific surface area of ​​0.93 m. ２ / g, melting point 170°C, no residual crotonic acid, residual 2-pentenoic acid, or residual 4-pentenoic acid was detected, and it was confirmed that the total amount of residual unsaturated fatty acids was 10 ppm by mass or less.

[0091] Example 4 A 2-liter autoclave equipped with a stirring blade and a thermometer was charged with 600 parts by mass of ion-exchanged water, 60 parts by mass of a nonionic surfactant (polyethylene oxide polypropylene oxide copolymer; molecular weight approximately 10,000), 20 parts by mass of polyethylene glycol (NOF Corporation's "PEG-20000"), and 5 parts by mass of polyvinyl alcohol (saponification degree: 72.9 mol%, viscosity of a 4% by weight aqueous solution at 20°C: 7.3 mPa s), and the autoclave was refluxed. After stirring at 200 rpm for 2 hours, 0.56 parts of dipotassium alkenyl succinate, 240 parts by mass of a 10% aqueous solution of tricalcium phosphate ("TCP-10U" manufactured by Taihei Chemical Industry Co., Ltd.), and 100 parts by mass of the poly(3-hydroxybutyrate-co-3-hydroxyvalerate) resin raw material pellets obtained in Production Example 1 were added, and the mixture was heated to an internal temperature of 165°C while stirring at 500 rpm. After reaching 165°C, the mixture was emulsified for 90 minutes. Subsequently, the mixture was cooled to 40°C while maintaining the rotation speed at 500 rpm to obtain a suspension. Next, 100 parts by mass of 20% hydrochloric acid was added to the resulting suspension to decompose the tricalcium phosphate, followed by filtration, washing, drying, and classification to obtain poly(3-hydroxybutyrate-co-3-hydroxyvalerate) resin particles. The resulting resin particles had a volume average primary particle diameter of 6.5 μm, a CV value of 37.6%, a contact angle of 85°, a circularity of 0.98, and a BET specific surface area of ​​0.83 m ２ / g, melting point 170°C, no residual crotonic acid, residual 2-pentenoic acid, or residual 4-pentenoic acid was detected, and it was confirmed that the total amount of residual unsaturated fatty acids was 10 ppm by mass or less.

[0092] Example 5 A 2-L autoclave equipped with a stirring blade and a thermometer was charged with 624 parts by mass of ion-exchanged water and 60 parts by mass of a nonionic surfactant (polyethylene oxide-polypropylene oxide copolymer; molecular weight approximately 8,000). The mixture was stirred at 200 rpm for 2 hours, after which 0.56 parts by mass of dipotassium alkenyl succinate, 240 parts by mass of a 10% aqueous solution of calcium phosphate tribasic ("TCP-10U" manufactured by Taihei Chemical Industry Co., Ltd.), and 100 parts by mass of the poly(3-hydroxybutyrate-co-3-hydroxyvalerate) resin raw material pellets obtained in Production Example 1 were added, and the mixture was heated to an internal temperature of 175°C while stirring at 300 rpm. After reaching 175°C, the mixture was emulsified for 30 minutes. The mixture was then cooled to 40°C while maintaining the rotation speed at 300 rpm to obtain a suspension. Next, 100 parts by mass of 20% hydrochloric acid was added to the resulting suspension to decompose the tricalcium phosphate, followed by filtration, washing, drying, and classification to obtain poly(3-hydroxybutyrate-co-3-hydroxyvalerate) resin particles. The resulting biodegradable resin particles had a volume-average primary particle diameter of 5.4 μm, a CV value of 36.6%, a contact angle of 97°, a circularity of 0.98, and a BET specific surface area of ​​0.89 m. ２ / g, melting point 170°C, no residual crotonic acid, residual 2-pentenoic acid, or residual 4-pentenoic acid was detected, and it was confirmed that the total amount of residual unsaturated fatty acids was 10 ppm by mass or less.

[0093] Example 6 Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) resin particles were obtained in the same manner as in Example 5, except that the emulsification temperature was changed to 165° C. The obtained resin particles had a volume average primary particle diameter of 25.0 μm, a CV value of 43.1%, a contact angle of 103°, a circularity of 0.97, and a BET specific surface area of ​​0.56 m ２ / g, melting point 170°C, no residual crotonic acid, residual 2-pentenoic acid, or residual 4-pentenoic acid was detected, and it was confirmed that the total amount of residual unsaturated fatty acids was 10 ppm by mass or less.

[0094] Example 7 599 parts by mass of ion-exchanged water, 80 parts by mass of a nonionic surfactant (polyethylene oxide-polypropylene oxide copolymer; molecular weight: approximately 8,000), and 5 parts by mass of polyvinyl alcohol (saponification degree: 72.9 mol %, viscosity of a 4 wt % aqueous solution at 20°C: 7.3 mPa s) were placed in a 2-L autoclave equipped with a stirring blade and a thermometer, and the mixture was stirred at 200 rpm for 2 hours. Thereafter, 0.56 parts by mass of dipotassium alkenylsuccinate, 240 parts by mass of a 10% aqueous solution of calcium phosphate tribasic ("TCP-10U" manufactured by Taihei Chemical Industry Co., Ltd.), and 100 parts by mass of the poly(3-hydroxybutyrate-co-3-hydroxyvalerate) resin raw material pellets obtained in Production Example 1 were added, and the mixture was heated to an internal temperature of 170°C while stirring at 500 rpm. After the temperature reached 170°C, the mixture was emulsified for 30 minutes. Thereafter, the mixture was cooled to 40°C while maintaining the rotation speed at 500 rpm, yielding a suspension. Next, 100 parts by mass of 20% hydrochloric acid was added to the resulting suspension to decompose the tricalcium phosphate, followed by filtration, washing, drying, and classification to yield poly(3-hydroxybutyrate-co-3-hydroxyvalerate) resin particles. The resulting resin particles had a volume-average primary particle diameter of 10.1 μm, a CV value of 37.1%, a contact angle of 93°, a circularity of 0.98, and a BET specific surface area of ​​0.77 m. ２ / g, melting point 170°C, no residual crotonic acid, residual 2-pentenoic acid, or residual 4-pentenoic acid was detected, and it was confirmed that the total amount of residual unsaturated fatty acids was 10 ppm by mass or less.

[0095] Example 8 A 2-L autoclave equipped with a stirring blade and a thermometer was charged with 604 parts by mass of ion-exchanged water, 60 parts by mass of a nonionic surfactant (polyethylene oxide-polypropylene oxide copolymer; molecular weight approximately 8,000), and 20 g of polyethylene glycol (NOF Corporation's "PEG-20000") and stirred at 200 rpm for 2 hours. After stirring at 200 rpm for 2 hours, 0.56 parts by mass of dipotassium alkenyl succinate, 240 parts by mass of a 10% aqueous solution of calcium phosphate tribasic (Taihei Chemical Industry Co., Ltd.'s "TCP-10U"), and 100 parts by mass of the poly(3-hydroxybutyrate-co-3-hydroxyvalerate) resin raw material pellets obtained in Production Example 1 were added, and the autoclave was heated to an internal temperature of 165°C while stirring at 500 rpm. After reaching 165°C, the autoclave was emulsified for 90 minutes. The autoclave was then cooled to 40°C while maintaining the rotation speed at 500 rpm to obtain a suspension. Next, 100 parts by mass of 20% hydrochloric acid was added to the resulting suspension to decompose the tricalcium phosphate, followed by filtration, washing, drying, and classification to obtain poly(3-hydroxybutyrate-co-3-hydroxyvalerate) resin particles. The resulting resin particles had a volume-average primary particle diameter of 8.5 μm, a CV value of 38.0%, a contact angle of 91°, a circularity of 0.98, and a BET specific surface area of ​​0.81 m. ２ / g, melting point 170°C, no residual crotonic acid, residual 2-pentenoic acid, or residual 4-pentenoic acid was detected, and it was confirmed that the total amount of residual unsaturated fatty acids was 10 ppm by mass or less.

[0096] Comparative Example 1 750 parts by mass of ion-exchanged water, 250 parts by mass of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) resin (melting point 137°C), 7.5 parts by mass of a nonionic surfactant (sorbitan monolaurate), and 50 parts by mass of polyvinyl alcohol (viscosity of a 4 wt% aqueous solution at 20°C: 25 mPa s) were mixed in a 2 L autoclave equipped with a stirring blade and a thermometer, and the mixture was heated to an internal temperature of 160°C, stirred at 400 rpm for 10 hours, and then cooled to 50°C to obtain a suspension. An oxidizing agent was added to the suspension, and the mixture was filtered, washed, dried, and classified to obtain poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) resin particles. The resulting resin particles had a volume average primary particle diameter of 10.5 μm, a CV value of 68.1%, a contact angle of 62°, a circularity of 0.92, and a BET specific surface area of ​​0.76 m ２ / g and the melting point was 137°C.

[0097] <<Evaluation of Biodegradable Resin Particles>> <Powder Property Test Evaluation> A powder property test evaluation was performed by having 10 panelists evaluate the feel (spreadability, skin compatibility) when applied to the skin for the resin particles of Examples 1 to 8 and Comparative Example 1. The evaluation was based on the number of panelists who answered that the feel when applied to the skin was good, with 9 to 10 panelists earning an A (pass), 7 to 8 panelists earning a B (pass), 4 to 6 panelists earning a C (fail), and 3 or less panelists earning a D (fail). The results of the powder property test evaluation were that the resin particles of Examples 1, 3, and 6 were rated B, the resin particles of Examples 2, 4, 5, 7, and 8 were rated A, and the resin particles of Comparative Example 1 were rated D.

[0098] <<Preparation of Topical Preparations>> <Examples 9 to 16> A mixture was prepared by mixing 15 parts by mass of the biodegradable resin particles obtained in Example 1, 21 parts by mass of sericite, 51 parts by mass of muscovite, 0.6 parts by mass of red iron oxide, 1 part by mass of yellow iron oxide, and 0.1 parts by mass of black iron oxide using a Henschel mixer. Furthermore, 10 parts by mass of cetyl 2-ethylhexanoate was mixed with 1 part by mass of sorbitan sesquioleate and 0.2 parts by mass of a preservative to prepare a solution. This mixture and the solution were mixed, and then 0.1 parts by mass of a fragrance was added, followed by pulverization and sieving to prepare a foundation material. This foundation material was compression-molded into a metal dish to prepare a powder foundation as a topical preparation according to Example 9. Powder foundations as topical preparations according to Examples 10 to 16 were prepared in the same manner as in Example 9, except that the biodegradable resin particles obtained in Examples 2 to 8 were used instead of the biodegradable resin particles obtained in Example 1.

[0099] <Comparative Example 2> A powder foundation as an external preparation according to Comparative Example 2 was prepared in the same manner as in Example 9, except that the biodegradable resin particles obtained in Comparative Example 1 were used instead of the biodegradable resin particles obtained in Example 1.

[0100] <<Evaluation of Topical Preparations>> <Topical Preparation Property Test Evaluation> The topical preparations (powder foundations) of Examples 9 to 16 and Comparative Example 2 were evaluated for each item of usability (spreadability on the skin, skin compatibility, and cosmetic longevity) by 10 panelists, to conduct a topical preparation property test evaluation. For each item of spreadability on the skin, skin compatibility, and cosmetic longevity, each panelist assigned a score of 5 points (very good), 4 points (good), 3 points (slightly good), 2 points (not very good), or 1 point (poor), and the average score was used as the topical preparation property test evaluation. Any item scored less than 3.0 points was deemed a failure. The results of the topical preparation property test evaluation were as shown in Table 1.

[0101]

[0102] As shown in Table 1, the powder foundation as an external preparation containing the biodegradable resin particles of the present invention had excellent spreadability and compatibility with the skin, and excellent makeup staying power.

[0103] <<Preparation of Coating Material>> <Example 17> A coating material was obtained by mixing 2 parts by mass of the poly(3-hydroxybutyrate-co-3-hydroxyvalerate) resin particles of Example 7 and 20 parts by mass of a commercially available acrylic water-based gloss paint ("Super Hit" manufactured by Campe Papio) for 3 minutes using a stirring and degassing device and degassing for 1 minute. The resulting coating material was applied to an ABS resin (acrylonitrile-butadiene-styrene resin) plate using a coating device equipped with a blade with a clearance of 50 μm, and then dried to obtain a coating film. The gloss (60°) of the resulting coating film was measured using a gloss checker (gloss meter) ("IG-330" manufactured by HORIBA). The gloss (60°) was 1.

Claims

1. Biodegradable resin particles containing polyhydroxyalkanoate resin, having a volume average primary particle diameter of 3 μm to 50 μm, a contact angle of 70° or more, a circularity of 0.90 to 1.00, and a BET specific surface area of 0.1 m ２ / g or more 10m ２ / g or less.

2. Biodegradable resin particles according to claim 1, having a melting point of 150°C or higher.

3. Biodegradable resin particles according to claim 1 or 2, wherein the total residual amount of unsaturated fatty acids is 10 mass ppm or less.

4. Biodegradable resin particles according to claim 1 or 2, wherein the polyhydroxyalkanoate resin is poly(3-hydroxybutyrate-co-3-hydroxyvalerate) resin.

5. An external preparation containing the resin particles according to claim 1 or 2.

6. A coating material comprising the resin particles according to claim 1 or 2.

7. A resin composition comprising the resin particles according to claim 1 or 2.

8. An anti-blocking agent comprising the resin particles according to claim 1 or 2.

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