JP6543920B2 - Polymer particles - Google Patents

Description

  The present invention relates to porous polymer fine particles made of an aliphatic polyester resin.

  Polymers are widely used in industrial materials and household products by being processed into films, fibers, various molded articles, etc. However, in recent years, the use as polymer fine particles in powder or granular form has spread There is.

  The polymer fine particles are mixed with a solvent, a viscous substance or a resin by utilizing the characteristics such as a large specific surface area and a solid but fluid property unlike the above-mentioned molded products etc. to modify these materials Used as an additive for toners, paints, cosmetics, toiletries, automotive and aircraft structural materials, construction materials, etc. in the printing material field, and used for viscosity control, reflection property improvement, toughness improvement or polishing performance etc. The function is given.

  Further, with the recent increase in interest in environmental problems, these polymer fine particles are also required to have materials aiming to reduce the environmental load. In particular, in consideration of the life cycle of materials, it has come to be required to obtain materials derived from non-petroleum materials. Among them, polymer microparticles added to household products such as paints, cosmetics and toiletries are released to the natural environment through wastewater, but they remain in the environment and have an adverse effect due to their stability in the environment. Are concerned. In particular, the need for scrubs and the like having the function of removing stains contained in face wash is increasing.

  Under such circumstances, these polymer fine particles are also required to have biodegradability and low environmental load characteristics, and in particular, development of polymer fine particles using aliphatic polyester as a material is required. As the conventional aliphatic polyester particles, development has been promoted mainly using polylactic acid (hereinafter sometimes referred to as PLA) as a material, but decomposition in the environment, especially activity in sewage treatment plants etc. For decomposition in sludge, the decomposition rate is not always sufficient, and particles of aliphatic polyester material having a higher decomposition rate have been required.

  As a method for producing aliphatic polyester particles including PLA, pulverization methods typified by freeze pulverization and the like (patent documents 1 and 2), they are dissolved in a solvent under high temperature and then cooled for precipitation or dissolved in a solvent A polylactic acid-based resin is obtained by mixing a polylactic acid-based resin and a resin incompatible with each other in a mixing machine such as a solvent soluble precipitation method (patent documents 3 and 4) which precipitates out by adding a solvent Melt-kneading to obtain porous aliphatic polyester resin fine particles by forming a resin composition having a resin incompatible with a polylactic acid-based resin as a continuous phase in a dispersed phase, and removing the incompatible resin. The law (patent documents 5 and 6) etc. are known.

  On the other hand, Patent Document 7 discloses a method for producing fine particles having a narrow particle size distribution applicable to a wide range of polymers, among which mention is made of micronization of polyesters, but mainly semi-aromatic compounds. The main focus is on polyesters, and a method for producing microparticles using biodegradable aliphatic polyesters is not described.

  Also, as porous aliphatic polyester particles, biodegradable porous hollow particles made of a block copolymer of an aliphatic polyester resin and a hydrophilic polymer such as polyethylene glycol are disclosed (Patent Document 8) However, this material is a special block polymer, which is not as versatile as used in industry, and development of aliphatic polyester particles using more realistic materials has been desired.

JP 2000-7789 A JP, 2001-288273, A JP 2005-2302 A JP, 2009-242728, A Unexamined-Japanese-Patent No. 2004-269865 JP 2005-200663A International Publication No. 2009/142231 WO 2010/101240

  An object of the present invention is to provide a porous aliphatic polyester fine particle which is useful as a scrub for a face wash, using a material having a reduced environmental load.

  Aliphatic polyester fine particles such as PLA particles described in Patent Documents 1 to 6 described above are spherical particles, or irregularly shaped particles due to crushing or precipitation, but sufficiently exhibit the function of removing dirt required as particles for scrub applications The porosity was not high enough to do.

  Particles for scrub applications are required to have high porosity and a material that absorbs a large amount of oil in order to remove skin stains during face washing, and the provision of such particles has been an issue.

As a result of intensive studies by the present inventors in order to achieve the above object, the following invention has been achieved.
That is, the present invention
“(1) obtained from aliphatic polyester obtained from bifunctional aliphatic hydroxycarboxylic acid having 4 or more carbon atoms, aliphatic dicarboxylic acid and / or aliphatic polyester and lactone obtained from an ester-forming derivative thereof and an aliphatic diol Polymer microparticles comprising an aliphatic polyester selected from the group consisting of aliphatic polyesters, wherein the linseed oil absorption is 120 ml / 100 g or more and 1000 ml / 100 g or less.
(2) Aliphatic polyester is represented by the formula (1): [-CHR ₁ -CH ₂ -CO-O-] (wherein, R ₁ represents an alkyl group represented by C _n H _{2n + 1} , n = 1 to 2) 15 is an integer of repeating units and _{R 2} represented by not the same), the formula _{(2):. [- CHR} 2 -CH 2 -CO-O -] ( wherein, _{R 2} is _C m H represents an alkyl group represented by _{2m + 1,} is an integer of m = 1 to 15, polymer microparticles of the R ₁ is an aliphatic polyester comprising a repeating unit represented by not identical.) (1).
(3) The polymer particle according to (1) or (2), wherein the average particle diameter of the polymer particle is 1 to 1000 μm. ".

  The fine polymer particles comprising the aliphatic polyester resin of the present invention are useful for scrubbing and the like because they have high porosity, a high oil absorption performance and a function of removing sebum dirt etc., and because they have biodegradability properties, the earth It is widely useful as an environmentally-friendly high-performance material.

FIG. 1 is a scanning electron micrograph of the porous aliphatic polyester fine particles produced in Example 1. FIG. 2 is a particle size distribution chart of the porous aliphatic polyester fine particles produced in Example 1.

  Hereinafter, the present invention will be described in detail.

  The polymer fine particles in the present invention refer to polymer fine particles having a porous shape and having a powdery form made of an aliphatic polyester.

  The feature of the polymer fine particle in the present invention is that the average particle size is small and the surface has a porous shape, and it is possible to retain a large amount of oil and water in its pores, so that it is lipophilic. Since the hydrophilicity is improved and the particle size is small, it is possible to impart smoothness which can not be achieved with conventional fine particles. Therefore, it is suitably used when coexistence of oil absorption and smoothness is required, such as in the field of cosmetics and toiletries.

  The polymer fine particles in the present invention do not include hollow porous particles in which the capsule membrane covers the hollow portion.

  The upper limit of the average particle size of the polymer fine particles in the present invention is usually 1000 μm or less, preferably 500 μm or less since finer ones can impart smoothness and good feel in applications such as cosmetics and face cleansers. More preferably, it is 300 μm or less, more preferably 100 μm or less, particularly preferably 50 μm or less, and particularly preferably 30 μm or less. The appropriate particle size range is determined according to the application.

  The lower limit of the average particle size of the polymer fine particles is 1 μm or more, preferably 1 μm or more, more preferably 2 μm or more, particularly preferably 3 μm or more, because aggregation of the particles is likely to occur when used in cosmetics etc. Preferably, 5 μm or more is the most preferable.

  The average particle size of the polymer fine particles in the present invention refers to the volume average particle size measured by a laser diffraction / scattering type particle size distribution meter.

  The polymer fine particles of the present invention are characterized in that the particle size distribution is narrow, and the particle size distribution index obtained by dividing the volume average particle size by the number average particle size is preferably 5 or less, particularly when used for cosmetics. The flow of particles as a body is improved and a smoother feeling is given. According to a preferred embodiment, the particle size distribution index is 4 or less, according to a more preferred embodiment 3 or less, more preferably 2 or less, particularly preferably 1.5 or less. Also, the lower limit value thereof is theoretically 1.

  Here, the number average particle diameter of the polymer fine particles means the number average particle diameter measured by a laser diffraction / scattering type particle size distribution analyzer.

  The polymer fine particles in the present invention are characterized by being porous, but it is difficult to standardize using the porousness as a direct index, and therefore pigments defined by Japanese Industrial Standards as indirect indices The linseed oil absorption (refined linseed oil method JIS K5101), which is the test method, is used as an index.

In particular, in applications to cosmetics, paints and the like, it is preferable that the oil absorption of linseed oil is higher, preferably 100 ml / 100 g or more, more preferably 120 ml / 100 g or more, still more preferably 150 ml / 100 g or more, particularly preferably 200 ml / 100 g The above amount is particularly preferably 250 ml / 100 g or more, and most preferably 300 ml / 100 g or more.
The upper limit is not particularly limited, but is 1000 ml / 100 g or less.

  Moreover, it is preferable that the aliphatic polyester which comprises the polymer fine particle of this invention is 5 J / g or more in melting enthalpy. The heat enthalpy is preferably 10 J / g or more, more preferably 20 J / g or more, and still more preferably 30 J / g or more, since the higher the crystallinity, the higher the heat resistance and the durability. Moreover, the upper limit is 100 J / g or less. The melting enthalpy can be calculated from the peak area indicating the heat of fusion when the temperature is raised to 200 ° C. under the conditions of a heating rate of 20 ° C. per minute by differential scanning calorimetry (DSC). The melting enthalpy of the aliphatic polyester in the present invention is a value measured by differential scanning calorimetry in the state of polymer fine particles.

  Furthermore, the sphericity of the polymer particles in the present invention is not particularly limited, but is preferably 80 or more, more preferably 85 or more, still more preferably 90 or more, particularly preferably 92 or more, and most preferably Preferably it is 95 or more. The upper limit is 100. When the sphericity is in the above range, the texture such as slipperiness is improved. The sphericity is calculated by observing particles with a scanning electron microscope, measuring the minor axis and the major axis, and calculating the average of 30 arbitrary particles according to the following formula.

  Note that n: the number of measurements is 30.

  The aliphatic polyester constituting the polymer fine particle of the present invention means an aliphatic polyester obtained from a bifunctional aliphatic hydroxycarboxylic acid having 4 or more carbon atoms, an aliphatic dicarboxylic acid and / or an ester-forming derivative thereof and an aliphatic diol It is an aliphatic polyester selected from the group consisting of aliphatic polyesters obtained and aliphatic polyesters obtained from lactones. The aliphatic polyester is preferably biodegradable.

  Among aliphatic polyesters as described above, examples of aliphatic polyesters obtained from a bifunctional aliphatic hydroxycarboxylic acid having 4 or more carbon atoms include polyglycolic acid such as poly (α-hydroxy acid), poly (3-hydroxy acid) Butanoic acid), poly (3-hydroxypentanoic acid), poly (3-hydroxyhexanoic acid), poly (3-hydroxyoctanoic acid), poly (4-hydroxybutanoic acid), poly (4-hydroxypentanoic acid), poly (4-hydroxyhexanoic acid), poly (4-hydroxyoctanoic acid) and the like. Examples of aliphatic polyesters obtained from aliphatic dicarboxylic acids and / or their ester-forming derivatives and aliphatic diols include polyethylene oxalate, polyethylene succinate, polyethylene adipate, polyethylene azelate, polybutylene oxalate, polybutylene succinate, Polybutylene adipate, polybutylene sebacate, polyhexamethylene sebacate, polyneopentyl oxalate and the like. Aliphatic polyesters obtained from lactones include poly (ω-hydroxyalkanoates) such as poly (ε-caprolactone) and poly (β-propiolactone). Also, these aliphatic polyesters may be copolymers, and as copolymers, poly (caprolactone / butylene succinate), poly (butylene succinate / carbonate), poly (butylene succinate / adipate), Examples include poly (butylene adipate / terephthalate), poly (tetramethylene adipate / terephthalate), poly (hydroxybutyrate / hydroxyhexanoate) and the like.

Among them, due to their high biodegradability, as the aliphatic polyester, a repeating unit represented by the formula (1): [-CHR ₁ -CH ₂ -CO-O-] and the formula (2): is preferably an aliphatic polyester copolymer consisting of repeating units represented by _{[-CHR 2 -CH 2 -CO-O-} ].

Here, in the formula, R ₁ and R ₂ each represent an alkyl group of a saturated aliphatic hydrocarbon represented by C _n H _{2n + 1} , and n is an integer of 1 to 15. In addition, the aliphatic polyester in the porous aliphatic polyester resin fine particles of the present invention is a copolymer in which R ₁ and R ₂ are different from each other because the biodegradability is higher than a polymer composed of a single monomer unit. .

  As such aliphatic polyester copolymers, poly [3-hydroxybutyrate-co-3-hydroxyvalerate], poly [3-hydroxybutyrate-co-3-hydroxyhexanoate], poly [3 -Hydroxybutyrate-co-3-hydroxy heptanoate], poly [3-hydroxybutyrate-co-3-hydroxyoctanoate], poly [3-hydroxybutyrate-co-3-hydroxydecanoate] , Poly [3-hydroxybutyrate-co-3-hydroxydodecanoate], poly [3-hydroxybutyrate-co-3-hydroxyoctadecanoate], poly [3-hydroxyvalerate-co-3- 3 Hydroxyhexanoate], poly [3-hydroxyvalerate-co-3-hydroxyheptanoate , Poly [3-hydroxyvalerate-co-3-hydroxyoctanoate], poly [3-hydroxyvalerate-co-3-hydroxydecanoate], poly [3-hydroxyvalerate-co-3-hydroxyl Dodecanoate], poly [3-hydroxyvalerate-co-3-hydroxyoctadecanoate], poly [3-hydroxyhexanoate-co-3-hydroxyheptanoate], poly [3-hydroxyhexano] Aate-co-3-hydroxyoctanoate], poly [3-hydroxyhexanoate-co-3-hydroxydecanoate], poly [3-hydroxyhexanoate-co-3-hydroxydodecanoate], Poly [3-hydroxyhexanoate-co-3-hydroxyoctadecanoate] etc. That. Among them, poly [3-hydroxybutyrate-co-3-hydroxyvalerate], poly [3-hydroxybutyrate-co-3-hydroxyhexano] from the viewpoint of good balance between stability upon use and biodegradability. And poly [3-hydroxyvalerate-co-3-hydroxyhexanoate] are preferred, and poly [3-hydroxybutyrate-co-3-hydroxyvalerate], poly [3-hydroxybutyrate-co- Particular preference is given to 3-hydroxyhexanoate]. (Here, -co- represents copolymerization.)

  The repeating unit of the aliphatic polyester constituting the polymer fine particle in the present invention has asymmetric carbon in the molecular structure, but the copolymerization ratio of the R form and the S form is not particularly determined, and any copolymerization ratio may be used. Good.

The copolymerization composition of the aliphatic polyester constituting the polymer fine particle of the present invention is not particularly limited because it is adjusted according to the purpose of using the porous aliphatic polyester resin fine particle, but the formula (1): [ If exemplified as the material ratio of the repeating unit represented by -CHR ₁ -CH ₂ -CO-O-] to the repeating unit represented by the formula (2): [-CHR ₂ -CH ₂ -CO-O-] , 1/99 to 99/1 (weight ratio), preferably 10/90 to 90/10, more preferably 20/80 to 80/20, particularly preferably 30/70 to 70 It is / 30.

Moreover, in the aliphatic polyester resin in the present invention, a repeating unit represented by: [-CHR ₁ -CH ₂ -CO-O-] and a formula (2): [-CHR ₂ -CH ₂ -CO-O-] There is no particular limitation on the arrangement mode of the repeating unit shown by and any of a block copolymer, an alternating copolymer, a random copolymer and a graft copolymer may be used. Random copolymers are preferred from the viewpoint of easy production of particles.

  The molecular weight of the aliphatic polyester constituting the polymer fine particle of the present invention is not particularly limited, but the lower limit of its weight average molecular weight (Mw) is 1,000 or more, preferably 10,000 or more, more preferably Is 20,000 or more, more preferably 50,000 or more. In addition, the upper limit of the weight average molecular weight is 1,000,000.

  The molecular weight distribution of the molecular weight of the aliphatic polyester constituting the polymer fine particle of the present invention is not particularly limited, but the upper limit is 10 or less in molecular weight distribution index (PDI) which is the ratio of weight average molecular weight and number average molecular weight Preferably it is 5 or less, More preferably, it is 4 or less, Most preferably, it is 3 or less. Also, the lower limit is theoretically 1.

  Here, the molecular weight and molecular weight distribution of the aliphatic polyester are those determined in terms of polymethyl methacrylate (PMMA) by gel permeation chromatography.

  Thus, the polymer microparticles of the present invention can be extremely useful and practically used in industrial and various applications. Specifically, skin care product additives such as facial cleanser, sunscreen agent, cleansing agent, lotion, milk, serum, cream, cold cream, after shaving lotion, shaving soap, oil dripping paper, matifant agent, etc. Cosmetics such as foundation, lotion, lotion, mascara, face powder, oran, black ink, mascara, eye line, eye shadow, eye shadow base, nose shadow, lipstick, gloss, gloss on the side, oar, nail polish, top coat, etc. Or its modifiers, shampoos, dry shampoos, conditioners, rinses, rinse-in shampoos, treatments, hair tonics, hair setting agents, additives for hair care products such as hair oils, pomades, hair coloring agents, perfumes, eau de colón, deodora Additives for amenity products such as baby powder, tooth powder, mouthwash, lip balm and soap, additives for toners, rheology modifiers such as paints, diagnostic test agents for medical use, automotive materials, molding materials etc. Products, mechanical property improvers for films, fibers, etc., materials for resin moldings such as rapid prototyping and rapid manufacturing, materials for flash molding, paste resins for plastic sol, powder blocking materials, powders Body flow improver, lubricant, rubber compounding agent, abrasive, thickener, filter agent and filter aid, gelling agent, flocculant, additive for paint, oil absorbing agent, mold release agent, plastic film Various improvements such as sheet slip improvers, antiblocking agents, gloss adjusters, matte finishers, light diffusers, surface high hardness improvers, toughness improvers, etc. Agents, spacers for liquid crystal displays, fillers for chromatography, substrates and additives for cosmetic foundations, adjuvants for microcapsules, medical materials such as drug delivery systems and diagnostic agents, retention agents for fragrances and pesticides, chemical reactions Catalysts and their supports, gas adsorbents, sintered materials for ceramic processing, standard particles for measurement and analysis, particles for the food industry field, materials for powder coatings, toners for electrophotographic development, etc. .

  In addition, porous aliphatic polyester resin particles are conventionally used because they have biodegradability and degrade in the environment with an appropriate degradation rate, and thus have characteristics as a material with low environmental impact. It is possible to replace non-biodegradable polymer microparticles. From this, as a specific application of the above-mentioned resin molded object, film, fiber, etc., for example, housing of electric equipment, housing of OA equipment, various covers, various gears, various cases, sensors, LED lamps, connectors, sockets Typical examples are resistors, relay cases, switches, various terminal boards, plugs, printed wiring boards, tuners, speakers, microphones, headphones, small motors, power modules, housings, semiconductors, liquid crystals, motor brush holders, computer parts, etc. Electrical and electronic parts, TV parts, irons, hair dryers, rice cooker parts, microwave oven parts, acoustic parts, audio equipment parts such as audio / laser disc (registered trademark) and compact discs, lenses for photographing such as cameras, finders , Household and office work electrical appliance parts represented by filters, prisms, Fresnel lenses and other imaging equipment parts, lighting parts, refrigerator parts, air conditioner parts etc. Telephone parts, copier parts, various disc substrate protective films, optical disc players Information equipment related parts such as pickup lenses, optical fibers, optical switches, optical connectors, light guide plates for liquid crystal displays, Fresnel lenses, polarizing plates, polarizing plate protective films, retardation films, light diffusion films, viewing angle widening films, reflective films, Represented by antireflective film, antiglare film, brightness enhancement film, prism sheet, light guide film for touch panel, jig for cleaning, motor parts, mechanical parts represented by lighters, typewriters, microscopes, binoculars, watches etc. Optical instruments, precision machine related Products, Fuel-related / Exhaust / Intake-related pipes, Air intake nozzles Snorkels, Intake manifolds, Fuel pumps, Connectors for fuses, Horn terminals, Electrical parts insulation plates, Lamp sockets, Lamp reflectors, Lamp housings, Engine oil filters, Ignitions The device case is cited, which is extremely effective for these various uses.

  The porous aliphatic polyester resin particles in the present invention can also be obtained by utilizing well-known techniques such as the resin particle production method mentioned in the prior art literature, for example, the solvent dissolution precipitation method and the forced melt-kneading method. As a method for easy production, the technique of Patent Document 7, that is, a solution phase containing Polymer A as a main component and a solution phase containing Polymer B as a main component by dissolving and mixing Polymer A, Polymer B and an organic solvent A method of precipitating fine particles of polymer A by contacting an poor solvent of polymer A after forming an emulsion in a system of phase separation into two phases, that is, utilizing phase separation by a mixed solution of two kinds of polymers Can be produced by applying the particle formation method described above and using an aliphatic polyester as the polymer A.

  In the granulation method utilizing phase separation with a mixture of two types of polymer solutions, which is mentioned as the most preferable method for producing porous aliphatic polyester resin particles, examples of the organic solvent to be used include ethyl acetate, methyl acetate, propion Ester solvents such as methyl propionate, ethyl propionate, methyl butanoate, ethyl butanoate, methyl acetoacetate, ethyl acetoacetate, chloroform, bromoform, methylene chloride, 1,2-dichloroethane, 1,1,1-trichloroethane, chlorobenzene Halogenated hydrocarbon solvents such as 2,6-dichlorotoluene, ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone and methyl butyl ketone, acetal solutions such as dimethyl acetal, diethyl acetal, dipropyl acetal and dioxolane Dimethylether, diethylether, dipropylether, diisopropylether, dibutylether, dipentylether, dihexylether, dioctylether, diisoamylether, tert-amylmethylether, tert-butylethylether, butylmethylether, butylethylether, 1 -Methoxyethane (monoglyme), 1-ethoxyethane, diethylene glycol dimethyl ether (diglyme), ethylene glycol diethyl ether, 2-methoxyethyl ether, di (ethylene glycol) diethyl ether, di (ethylene glycol) dibutyl ether, triethylene glycol dimethyl ether, Tetrahydrofuran, 2-Methyltetrahydrofuran, 2, 5-Dimethyltetrahydrofuran Orchid, 2,2,5,5-tetramethylhydrofuran, 2,3-dihydrofuran, 2,5-dihydrofuran, tetrahydropyran, 3-methyltetrahydropyran, 1,4-dioxane, anisole, phenetole (ethyl phenol ), Ether solvents such as diphenyl ether, 3-phenoxytoluene, p-tolyl ether, 1,3-diphenoxybenzene, 1,2-diphenoxyethane, N-methyl-2-pyrrolidone, dimethyl sulfoxide, N, N- Aprotic polar solvents such as dimethylformamide, N, N-dimethylacetamide, propylene carbonate, trimethylphosphoric acid, 1,3-dimethyl-2-imidazolidinone, sulfolane, formic acid, acetic acid, propionic acid, butyric acid, lactic acid etc. A carboxylic acid solvent etc. are mentioned.

  Preferably, ester solvents such as methyl acetoacetate and ethyl acetoacetate having high solubility of aliphatic polyester resin, chloroform, bromoform, methylene chloride, 1,2-dichloroethane, 1,1,1-trichloroethane, chlorobenzene, 2 Hydrocarbon solvents such as 1,6-dichlorotoluene, ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone and methyl butyl ketone, N-methyl-2-pyrrolidone, dimethyl sulfoxide, N, N-dimethylformamide, N Aprotic polar solvents such as N, N-dimethylacetamide, propylene carbonate, trimethyl phosphoric acid, 1,3-dimethyl-2-imidazolidinone and sulfolane; carboxylic acid solvents such as formic acid, acetic acid, propionic acid, butyric acid and lactic acid Especially Or ester solvents such as methyl acetoacetate, ethyl acetoacetate, aprotic polar solvents such as N-methyl-2-pyrrolidone, dimethyl sulfoxide, N, N-dimethylformamide, N, N-dimethylacetamide, etc. And ester solvents such as methyl acetoacetate and ethyl acetoacetate.

  These organic solvents may be used as a mixture as long as the effects of the present invention are not impaired, but it is preferable to use them alone from the viewpoint of recovery and reuse of the organic solvent.

  A polymer different from the aliphatic polyester resin (B) corresponding to the polymer B in the particle formation method utilizing phase separation with two polymer mixture solutions mentioned as the most preferable method for producing porous aliphatic polyester resin particles Among polymers different from aliphatic polyester resins, thermoplastic resins and thermosetting resins are mentioned, but thermoplastic resins are preferable from the viewpoint of easy dissolution in organic solvents.

  Specifically, poly (vinyl alcohol) (which may be fully saponified or partially saponified poly (vinyl alcohol)), poly (vinyl alcohol-ethylene) copolymer (completely saponified type or a portion) It may be a saponified poly (vinyl alcohol-ethylene) copolymer), polyvinyl pyrrolidone, poly (ethylene glycol), poly (ethylene oxide), sucrose fatty acid ester, poly (oxyethylene fatty acid ester), poly (Oxyethylene laurine fatty acid ester), poly (oxyethylene glycol monofatty acid ester), poly (oxyethylene alkyl phenyl ether), poly (oxyalkyl ether), polyacrylic acid, sodium polyacrylate, polymethacrylic acid, polymethacrylic acid Sodium, polystyrene sulfonic acid Sodium polystyrene sulfonate, polyvinyl pyrrolidinium chloride, poly (styrene-maleic acid) copolymer, amino poly (acrylamide), poly (para vinyl phenol), polyallylamine, polyvinyl ether, polyvinyl formal, poly (acrylamide), poly (poly (acrylamide)) Synthetic resin such as methacrylamide), poly (oxyethylene amine), poly (vinyl pyrrolidone), poly (vinyl pyridine), polyamino sulfone, polyethylene imine, disaccharide such as maltose, cellobiose, lactose, sucrose, cellulose, chitosan, hydroxy Ethyl cellulose, hydroxypropyl cellulose, methyl cellulose, ethyl cellulose, ethyl hydroxycellulose, carboxymethyl ethyl cellulose, carboxymethyl cellulose Cellulose, sodium carboxymethylcellulose, cellulose derivatives such as cellulose ester, amylose and derivatives thereof, starch and derivatives thereof, polysaccharides such as dextrin, cyclodextrin, sodium alginate and derivatives thereof or derivatives thereof, gelatin, casein, collagen, albumin, fibroin And keratin, fibrin, carrageenan, chondroitin sulfate, gum arabic, agar, proteins, etc., and since the particle size distribution becomes narrow, poly (vinyl alcohol) (a fully saponified or partially saponified poly) is preferred. (May be vinyl alcohol), poly (vinyl alcohol-ethylene) copolymer (may be completely saponified type or partially saponified type poly (vinyl alcohol-ethylene) copolymer) Poly (ethylene glycol), poly (ethylene oxide), sucrose fatty acid ester, poly (oxyethylene alkyl phenyl ether), poly (oxyalkyl ether), poly (acrylic acid), poly (methacrylic acid), carboxymethyl cellulose, hydroxy Ethylcellulose, hydroxypropylcellulose, methylcellulose, ethylcellulose, ethylhydroxycellulose, carboxymethylethylcellulose, carboxymethylcellulose, carboxymethylcellulose sodium, cellulose derivatives such as cellulose ester, polyvinyl pyrrolidone, more preferably poly (vinyl alcohol) (completely saponified And partially saponified poly (vinyl alcohol), poly (vinyl alcohol-ethylene) co Combined (completely saponified or partially saponified poly (vinyl alcohol-ethylene) copolymer), poly (ethylene glycol), poly (ethylene oxide), carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, ethyl cellulose, Ethylhydroxycellulose, carboxymethylethylcellulose, carboxymethylcellulose, sodium carboxymethylcellulose, cellulose derivatives such as cellulose ester, polyvinyl pyrrolidone, particularly preferably poly (vinyl alcohol) (completely saponified type or partially saponified type poly (vinyl) Alcohol), poly (ethylene glycol), poly (ethylene oxide), hydroxypropyl cellulose.

  The molecular weight of the polymer different from the aliphatic polyester resin (B) is preferably 1,000 to 100,000,000, more preferably 1,000 to 10,000,000, and still more preferably weight average molecular weight. , 5,000 to 1,000,000, particularly preferably 10,000 to 500,000, and the most preferable range is 10,000 to 100,000.

  The weight average molecular weight as used herein refers to a weight average molecular weight measured by gel permeation chromatography (GPC) using water as a solvent and converted to polyethylene glycol.

  If it can not be measured with water, dimethylformamide is used, if it can not be measured, tetrahydrofuran is used, and if it can not be measured, hexafluoroisopropanol is used.

  Specifically, as a particle formation method using phase separation with two polymer mixed solutions recommended in the present invention, “(A) aliphatic polyester resin and (B) different polymer from aliphatic polyester resin and (C ) Using a system in which an organic solvent is dissolved and mixed, and a solution phase composed mainly of an aliphatic polyester resin and a solution phase composed mainly of a polymer different from the aliphatic polyester resin are separated into two phases, Specifically, when (A) aliphatic polyester resin and (B) different polymers from aliphatic polyester resin (hereinafter sometimes referred to as polymer B) and (C) organic solvent are mixed, aliphatic polyester resin It refers to a system that divides into two phases, a solution phase mainly comprising a solution phase and an aliphatic polyester resin a solution phase mainly comprising a different polymer.

  By using such a phase separation system, it is possible to mix and emulsify to form an emulsion under phase separation conditions.

  In the above, as to whether or not the polymer is dissolved, the temperature at which the present invention is carried out, that is, (A) aliphatic polyester resin and (B) different polymer from aliphatic polyester resin are dissolved and mixed to separate two phases. At the temperature at the time of (C), it discriminate | determines whether it dissolves more than 1 mass% with respect to the organic solvent.

  In this emulsion, the aliphatic polyester resin solution phase becomes the dispersed phase, the polymer B solution phase becomes the continuous phase, and the aliphatic polyester in the emulsion is brought into contact with the emulsion with the poor solvent of the aliphatic polyester resin. Porous aliphatic polyester resin microparticles are precipitated from the resin solution phase, and polymer microparticles composed of (A) aliphatic polyester resin can be obtained.

  The poor solvent of the aliphatic polyester resin in the most preferred method of producing the polymer fine particle of the present invention refers to a solvent which does not dissolve the (A) aliphatic polyester resin. The solubility in a poor solvent of (A) aliphatic polyester resin is 1% by mass or less, more preferably 0.5% by mass or less, and still more preferably 0.1% by mass. % Or less.

  In the most preferred method of producing the polymer fine particle of the present invention, the poor solvent of the aliphatic polyester resin is used, and such poor solvent is (A) a poor solvent of aliphatic polyester resin and (B) aliphatic polyester resin It is preferable that it is a solvent which dissolves a different polymer. Thereby, the porous aliphatic polyester resin fine particle comprised with (A) aliphatic polyester resin can be deposited efficiently. In addition, it is preferable that the solvent for dissolving the polymer different from (A) aliphatic polyester resin and (B) aliphatic polyester resin and the poor solvent of the aliphatic polyester resin be uniformly mixed.

  As the poor solvent in the most preferable method of producing the polymer fine particle of the present invention, the kind of (A) aliphatic polyester resin to be used, desirably (A) aliphatic polyester resin and (B) different polymers from aliphatic polyester resin Although it changes with both types, if it illustrates concretely, aliphatic hydrocarbon solvents, such as pentane, hexane, heptane, octane, nonane, n-decane, n-dodecane, n-tridecane, cyclohexane, cyclopentane, etc. Aromatic hydrocarbon solvents such as benzene, toluene and xylene; alcohol solvents such as methanol, ethanol, 1-propanol and 2-propanol; and solvents selected from at least one of water.

  (A) Aromatic hydrocarbon solvents, aliphatic hydrocarbon solvents, alcohol solvents, and water are preferable from the viewpoint of efficiently forming aliphatic polyester resin into particles, and alcohol solvents are more preferable. Water, most preferably water.

  In the most preferred method of producing the polymer fine particles of the present invention, (A) aliphatic polyester resin, (B) polymer different from aliphatic polyester resin, (C) organic solvent capable of dissolving them, and poor solvent for aliphatic polyester resin By appropriately selecting and combining, it is possible to precipitate the aliphatic polyester resin efficiently and obtain polymer fine particles.

  (A) Aliphatic polyester resin, (B) Polymer different from aliphatic polyester resin, and a solution obtained by mixing and dissolving (C) organic solvent which dissolves these, a solution phase containing aliphatic polyester resin as a main component, It is necessary to separate into two phases of a solution phase that is based on a polymer different from an aliphatic polyester resin. Under the present circumstances, (C) organic solvent of the solution phase which has an aliphatic polyester resin as a main component, and (C) organic solvent which has a different polymer from the (B) aliphatic polyester resin as a main component are the same. Although they may be different, substantially the same solvent is preferable.

  The conditions for producing a two-phase separated state are: (A) aliphatic polyester resin or (B) type of polymer different from aliphatic polyester resin, (A) aliphatic polyester resin or (B) aliphatic polyester resin It depends on the molecular weight of different polymers, (C) type of organic solvent, (A) concentration of polymers different from aliphatic polyester resin or (B) aliphatic polyester resin, temperature and pressure at which the invention is to be carried out.

  In order to obtain conditions that are likely to be in a phase separated state, the difference in solubility parameter (hereinafter sometimes referred to as SP value) of polymers different from (A) aliphatic polyester resin and (B) aliphatic polyester resin is different. It is preferable to have

At this time, the difference in SP value is 1 (J / cm ³ ) ^1/2 or more, more preferably 2 (J / cm ³ ) ^1/2 or more, still more preferably 3 (J / cm ³ ) ^1/2 or more Particularly preferably, it is 5 (J / cm ³ ) ^1/2 or more, and most preferably 8 (J / cm ³ ) ^1/2 or more. If the SP value is in this range, phase separation easily occurs and phase separation is easily performed, so that it is possible to obtain porous aliphatic polyester resin fine particles having a higher content of aliphatic polyester resin component. . There is no particular limitation as long as both (A) aliphatic polyester resin and (B) polymer different from aliphatic polyester resin are soluble in (C) organic solvent, but preferably 20 (the upper limit of the difference in SP value) J / cm ³ ) ^1/2 or less, more preferably 15 (J / cm ³ ) ^1/2 or less, and still more preferably 10 (J / cm ³ ) ^1/2 or less. In addition, SP value here is calculated based on the Fedor's estimation method, and is calculated based on cohesive energy density and molar molecular volume (hereinafter, it may be referred to as calculation method). (“SP Value Basics / Applications and Calculation Methods” by Hideki Yamamoto, Inc., Information Technology Co., Ltd., published on March 31, 2005). In the case where calculation is not possible by this method, the SP value is calculated by an experimental method (hereinafter sometimes referred to as experimental method) by determination of whether or not the solubility parameter dissolves in a known solvent (hereinafter sometimes referred to as experimental method). Substitute ("Polymer Handbook Fourth Edition" by J. Brand, published by Wiley 1998).

  In order to select the conditions for phase separation, the ratio of the three components of (A) aliphatic polyester resin, (B) polymer different from aliphatic polyester resin, and (C) organic solvent that dissolves these is changed. A three-component phase diagram can be identified, which can be created by a simple preliminary experiment based on observation of different states.

  The phase diagram is prepared by mixing and dissolving (A) aliphatic polyester resin, (B) polymer different from aliphatic polyester resin, and (C) organic solvent in an arbitrary ratio and leaving it to stand. The phase separation is carried out by performing determination of whether or not to occur at at least three points, preferably at least five points, more preferably at least ten points, and separating an area separating into two phases and an area becoming one phase. You will be able to identify the conditions that will be in the state.

  Under the present circumstances, in order to determine whether it is in a phase-separated state, (A) aliphatic polyester resin, (B) polymers different from aliphatic polyester resin, temperature and pressure at which the present invention is to be practiced (A) Aliphatic polyester resin, (B) Polymer different from aliphatic polyester resin, and (C) Organic solvent after adjusting to an arbitrary ratio, (A) Aliphatic polyester resin, (B) Aliphatic polyester resin After completely dissolving and dissolving a different polymer, thoroughly stir, and leave for 3 days to check whether or not phase separation occurs macroscopically. However, in the case of a sufficiently stable emulsion, macroscopic phase separation may not occur even after standing for 3 days. In that case, phase separation is determined based on whether microscopic phase separation is performed using an optical microscope, phase contrast microscope, or the like.

  Phase separation is formed by separating into (C) an aliphatic polyester resin solution phase mainly composed of an aliphatic polyester resin and a polymer B solution phase mainly composed of a polymer different from the aliphatic polyester resin in an organic solvent Be done. At this time, the aliphatic polyester resin solution phase is a phase in which (A) aliphatic polyester resin is mainly distributed, and the polymer B solution phase is a phase in which a polymer different from (B) aliphatic polyester resin is mainly distributed. is there. At this time, the aliphatic polyester resin solution phase and the polymer B solution phase seem to have a volume ratio according to the type and amount of polymer different from (A) aliphatic polyester resin and (B) aliphatic polyester resin. .

  The concentration of polymers different from (A) aliphatic polyester resin and (B) aliphatic polyester resin with respect to (C) organic solvent is (C), as the state of phase separation is obtained, and concentration which can be industrially practiced. It is premised that it is within the possible range of solubility in an organic solvent, but the lower limit is preferably more than 1% by mass, more preferably 2% by mass with respect to the total mass, and more preferably Is 3% by mass, more preferably 5% by mass. The upper limit of each is preferably 50% by mass, more preferably 30% by mass, and still more preferably 20% by mass.

  The interfacial tension between the two phases of the aliphatic polyester resin solution phase and the polymer B solution phase in the most preferred method of producing the polymer fine particles of the present invention is small because both phases are organic solvents, and their properties As a result, the produced emulsion can be stably maintained, so that the particle size distribution seems to be small.

The interfacial tension between the two phases in the most preferred method of producing the polymer microparticles of the present invention can be measured directly by the hanging drop method or the like in which different types of solutions are added to the commonly used solution. Although it can not be done, the interfacial tension can be estimated by estimating it from the surface tension of each phase with air. When the surface tension of each phase with air is r ₁ and r ₂ , the interfacial tension r _1/2 can be estimated by the absolute value of r _1/2 = r ₁ −r ₂ .

In this case, the upper limit of the preferable range of r _1/2 is 10 mN / m, more preferably 5 mN / m, still more preferably 3 mN / m, and particularly preferably 2 mN / m. . Moreover, the lower limit is more than 0 mN / m.

  The viscosity between the two phases in the most preferred method of producing the polymer fine particles of the present invention affects the average particle size and the particle size distribution, and the smaller the viscosity ratio, the smaller the particle size distribution tends to be.

  As a preferable range of the viscosity ratio between two phases in the most preferable method of producing the polymer fine particle of the present invention, the lower limit thereof is preferably 0.1 or more, more preferably 0.2 or more, and still more preferably 0.3. Or more, more preferably 0.5 or more, and particularly preferably 0.8 or more. The upper limit thereof is preferably 10 or less, more preferably 5 or less, still more preferably 3 or less, particularly preferably 1.5 or less, and particularly preferably 1.2 or less. However, the viscosity ratio between the two phases mentioned here is the temperature condition under which the most preferable method for producing porous aliphatic polyester resin particles is to be carried out, (A) aliphatic polyester resin solution phase / (B) fat It is defined that the polymer solution phase is different from the group polyester resin.

  Using the phase-separated system thus obtained, the phase-separated liquid phases are mixed, emulsified, and then polymer fine particles are produced.

  In order to carry out micronization, an emulsion formation and micronization process is carried out in a conventional reaction tank.

  The most preferable method for producing the polymer fine particle of the present invention is, from the industrial feasibility, the temperature at which the emulsion formation and micronization step is carried out is 0 ° C. or higher, and the upper limit is (A) aliphatic polyester resin, (B) A temperature at which a polymer different from the aliphatic polyester resin dissolves and phase separates, and is not particularly limited as long as the desired fine particles are obtained, but the lower limit is usually 0 ° C. or higher, preferably 10 C. or higher, more preferably 20.degree. C. or higher. The upper limit thereof is preferably 300 ° C. or less, more preferably 200 ° C. or less, more preferably 160 ° C. or less, particularly preferably 140 ° C. or less, and particularly preferably 100. It is less than ° C.

  The pressure suitable for carrying out the most preferred method of producing the polymer microparticles of the present invention ranges from normal pressure to 10 atm, from the industrial feasibility point of view. The preferred lower limit is 1 atm. The upper limit is preferably 5 atm, more preferably 3 atm, and more preferably 2 atm.

  Moreover, it is preferable to use an inert gas for the reaction tank. Specifically, nitrogen, helium, argon and carbon dioxide are preferable, and nitrogen and argon are preferable.

  Under such conditions, the phase separation system is mixed to form an emulsion. That is, an emulsion is formed by applying a shearing force to the phase separation solution obtained above.

  When forming an emulsion, the emulsion is formed so that (A) aliphatic polyester resin solution phase is in the form of particulate droplets, but generally, when phase separation is performed, (B) polymer solution different from aliphatic polyester resin When the volume of the phase is larger than the volume of the (A) aliphatic polyester resin solution phase, such a form of emulsion tends to be easily formed, and in particular, the volume ratio of the (A) aliphatic polyester resin solution phase is both phases. It is preferable that it is less than 0.5 with respect to the sum total volume 1 of, and it is preferable that it is between 0.4 and 0.1.

  When creating the above phase diagram, it is possible to set an appropriate range by simultaneously measuring the volume ratio in the concentration of each component.

  The fine particles obtained by the present production method become fine particles having a small particle size distribution, because a very uniform emulsion can be obtained at the stage of emulsion formation. This tendency is remarkable when using a single solvent which dissolves both (A) aliphatic polyester resin and (B) a polymer different from aliphatic polyester resin. For this reason, in order to obtain a shear force sufficient to form an emulsion, it is sufficient to use stirring according to a previously known method, and liquid phase stirring by a stirring blade, stirring by a continuous twin-screw mixer, by a homogenizer It can be mixed by a commonly known method such as mixing method, ultrasonic irradiation and the like.

  In particular, in the case of stirring by a stirring blade, although depending on the shape of the stirring blade, the stirring speed is preferably 50 rpm to 1,200 rpm, more preferably 100 rpm to 1,000 rpm, still more preferably 200 rpm to 800 rpm, particularly preferably Is 300 to 600 rpm.

  Specific examples of the stirring blade include propeller type, paddle type, flat paddle type, turbine type, double cone type, single cone type, single ribbon type, double ribbon type, screw type, helical ribbon type, etc. The materials are not particularly limited as long as the system can be sufficiently sheared. Moreover, in order to perform efficient stirring, you may install a baffle etc. in a tank.

  In addition, in order to generate an emulsion, not only a stirrer but also a widely known device such as an emulsifying machine or a dispersing machine may be used. Specifically, batch-type emulsification machines such as homogenizer (manufactured by IKA), Polytron (manufactured by Kinematica), TK autohomomixer (manufactured by Tokushu Kika Kogyo), Ebara Milder (manufactured by Kuwahara Seisakusho) , TK film mix, TK pipeline homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.), colloid mill (manufactured by Shinko Pantec Co., Ltd.), slasher, Trigonal wet pulverizer (manufactured by Mitsui Miike Kakoki Co., Ltd.), ultrasonic homogenizer, static A mixer etc. are mentioned.

  The emulsion thus obtained is subsequently subjected to the step of precipitating fine particles.

  (A) In order to obtain fine particles of aliphatic polyester resin, (A) A poor solvent for the aliphatic polyester resin is brought into contact with the emulsion produced in the above step to precipitate the fine particles with a diameter corresponding to the emulsion diameter. .

  The method of contacting the poor solvent with the emulsion may be a method of putting the emulsion in the poor solvent, or a method of putting the poor solvent in the emulsion, but a method of putting the poor solvent in the emulsion is preferable.

  At this time, the poor solvent is not particularly limited as long as the polymer fine particles produced in the present invention can be obtained, and any of continuous dropping method, divided addition method, and batch addition method may be used. In order to prevent aggregation, fusion, and coalescence, and increase in particle size distribution and formation of lumps larger than 1000 μm, it is preferable to use a continuous dropping method or a divided dropping method, which is industrially efficient. The most preferred is the continuous dropping method to carry out.

  In the most preferable method for producing the polymer fine particle of the present invention, the temperature at the time of contacting the poor solvent is not particularly limited as long as the polymer fine particle is deposited, and the lower limit is 0 ° C. or more and the upper limit is 300 It is the range below ° C. If the temperature is too low, the poor solvent solidifies and can not be used, so 10 ° C. or higher is preferable, and 20 ° C. or higher is more preferable. If the temperature is too high, thermal degradation of (A) aliphatic polyester resin and polymer different from (B) aliphatic polyester resin tends to progress, so 200 ° C. or less is preferable, more preferably 100 ° C. or less, More preferably, it is 90 ° C. or less.

  In the most preferred method of producing the polymer fine particle of the present invention, in order to advantageously obtain the polymer fine particle of the present invention, a crystalline (A) aliphatic polyester resin having a melting enthalpy of 5 J / g or more is used as a raw material Is preferred.

  When an amorphous aliphatic polyester resin having a melting enthalpy of less than 5 J / g is used as a raw material, volumetric shrinkage does not occur with crystallization, and the particles tend to be spherical nonporous, so the porous polymer of the present invention It is disadvantageous to obtain fine particles.

  As a contact temperature of the poor solvent in the most preferable method of producing the polymer fine particle of the present invention, (A) It is more advantageous to make it below the crystallization temperature of aliphatic polyester resin. The reason for this is not clear, but by setting the crystalline (A) aliphatic polyester resin below the crystallization temperature, crystallization of the aliphatic polyester resin dissolved in the emulsion droplets is promoted. It is thought that it is likely to become porous.

  The contact temperature of the poor solvent may be equal to or lower than the crystallization temperature, preferably 5 ° C. or less, more preferably 10 ° C. or less, still more preferably 15 ° C. or less, particularly preferably 20 ° C. It is below.

  The crystallization temperature of the (A) aliphatic polyester resin in the present invention indicates the temperature which appears at the time of crystallization again in the process of cooling the (A) aliphatic polyester resin once melted. The measurement method is a differential scanning calorimetry (DSC) measurement of the temperature at the peak apex showing the endothermic capacity when the temperature is raised to 200 ° C. at a speed of 20 ° C./min and the temperature is lowered at a speed of 1 ° C./min. It is. Moreover, when a peak does not appear at the time of temperature fall, it can be measured at the temperature of the peak apex which shows the endothermic capacity at the time of temperature rising to 200 ° C. under the conditions of speed 0.5 ° C./min.

  Moreover, as time to add a poor solvent, it is 10 minutes or more and 50 hours or less, More preferably, it is 15 minutes or more and 10 hours or less, More preferably, it is 30 minutes or more and 5 hours or less.

  If it is carried out in a time shorter than this range, the particle size distribution may become large or lumps may be formed as the emulsion is coagulated, fused and united. Also, if it is carried out for a longer time, it will be unrealistic when considering industrial practice.

  By carrying out within the range of this time, when converting from an emulsion to polymer particles, aggregation between particles can be suppressed, and polymer particles with a small particle size distribution can be obtained.

  Although the amount of the poor solvent to be added depends on the state of the emulsion, it is preferably 0.1 to 10 parts by mass, more preferably 0.1 to 5 parts by mass with respect to 1 part by mass of the total emulsion weight. Part, more preferably 0.2 to 3 parts by mass, particularly preferably 0.2 to 2 parts by mass, and most preferably 0.2 to 1.0 parts by mass is there.

  The contact time between the poor solvent and the emulsion may be any time sufficient for the fine particles to precipitate, but in order to cause sufficient precipitation and obtain efficient productivity, 5 minutes to 50 minutes after the end of the poor solvent addition. The time is preferably 5 minutes to 10 hours, more preferably 10 minutes to 5 hours, particularly preferably 20 minutes to 4 hours, and most preferably 30 minutes to 3 hours. It is within time.

  The fine polymer particle dispersion prepared in this manner is subjected to solid-liquid separation by a generally known method such as filtration, vacuum filtration, pressure filtration, centrifugal separation, centrifugal filtration, spray drying, etc. to recover fine particle powder. I can do it.

  The polymer fine particles subjected to solid-liquid separation are, if necessary, washed with a solvent or the like to remove adhered or contained impurities and the like for purification.

  In the method of the present invention, recycling is carried out by utilizing again a polymer different from the (C) organic solvent and (B) aliphatic polyester resin separated in the solid-liquid separation step carried out when obtaining the fine particle powder. It is possible.

  The solvent obtained by solid-liquid separation is a mixture of (B) a polymer different from the aliphatic polyester resin, (C) an organic solvent and an antisolvent. By removing the poor solvent from this solvent, it can be reused as a solvent for forming an emulsion. The method for removing the poor solvent is usually carried out by a known method, and specific examples include simple distillation, reduced pressure distillation, precision distillation, thin film distillation, extraction, membrane separation, etc., preferably simple distillation, reduced pressure It is a method by distillation and precision distillation.

  When performing distillation operations such as simple distillation and vacuum distillation, heat is applied to the system as in the case of polymer fine particle production, and (B) promotes thermal decomposition of a polymer different from aliphatic polyester resin and (C) an organic solvent From the viewpoint of the possibility, it is preferable to carry out in the absence of oxygen as much as possible, more preferably under an inert atmosphere. Specifically, it is preferable to carry out under nitrogen, helium, argon and carbon dioxide conditions. Moreover, you may re-add a phenolic compound as antioxidant.

  When recycling, it is preferable to remove the poor solvent as much as possible. Specifically, the remaining amount of the poor solvent is the total amount of (C) organic solvent to be recycled and (B) a different polymer from aliphatic polyester resin. In contrast, the content is 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less, particularly preferably 1% by mass or less. If it exceeds this range, the particle size distribution of the fine particles becomes large or the particles aggregate, which is not preferable.

  The amount of the poor solvent in the solvent used for recycling can be measured by a commonly known method, and can be measured by a gas chromatography method, Karl Fischer method or the like.

  In the operation of removing the poor solvent, practically, (C) the organic solvent, (B) the polymer different from the aliphatic polyester resin, etc. may be lost, so the composition ratio may be appropriately adjusted to the initial composition ratio. Is preferred.

  Hereinafter, the present invention will be described in detail based on examples, but the present invention is not limited thereto.

(1) Measurement of melting point and melting enthalpy (method of measuring melting point)
The melting point of the aliphatic polyester resin and the aliphatic polyester resin fine particle in the present invention is 200 ° C. at a temperature rising rate of 20 ° C./min according to differential scanning calorimetry (differential scanning calorimeter Q20 manufactured by TA Instruments Co., Ltd.). The temperature is raised to 20 ° C. at a temperature drop rate of 20 ° C./min, and the temperature is raised again to 200 ° C. under the conditions of a temperature rise rate of 20 ° C./min, and the peak temperature of the peak showing melting heat capacity It measured by computing.

(2) Weight Average Molecular Weight (i) Molecular Weight Measurement of Aliphatic Polyester Resin and Aliphatic Polyester Resin Fine Particles The weight average molecular weight is compared with a calibration curve of polymethyl methacrylate (PMMA) using gel permeation chromatography. Molecular weight was calculated.
Device: Waters LC system Column: Showa Denko HFIP-806M × 2 Mobile phase: sodium trifluoroacetate 10 mmol / L hexafluoroisopropanol solution Flow rate: 1.0 ml / min
Detection: Differential Refractometer Column temperature: 30 ° C.

(Ii) Molecular Weight Measurement of Polymer Different from Aliphatic Polyester The weight average molecular weight was calculated using gel permeation chromatography, and was compared with a calibration curve with polyethylene glycol to calculate the molecular weight.
Device: Shimadzu Corporation LC-10A series
Column: Showa Denko GF-7 MHQ × 2 Mobile phase: 10 mmol / L Lithium bromide aqueous solution Flow rate: 1.0 ml / min
Detection: Differential Refractometer Column temperature: 40 ° C.

(3) Measurement method of interfacial tension Kyowa Interface Science Co., Ltd. Automatic contact angle meter DM-501 as an apparatus, on an hot plate, aliphatic polyester solution phase, polymer B solution phase, surface tension between each phase and air The surface tension of each phase was determined as r ₁ and r _2, and the interfacial tension was calculated from the absolute value of (r ₁ −r ₂ ) which is the difference.

(4) Method of measuring average particle diameter and particle diameter distribution Measure volume average particle diameter and number average particle diameter using a laser diffraction scattering particle size distribution analyzer (Microtrac MT 3300 EX II) manufactured by Nikkiso Co., Ltd. The particle size was taken as the average particle size. In addition, the ratio of the volume average particle diameter to the number average particle diameter obtained above was obtained to obtain a particle diameter distribution index showing a particle diameter distribution.

  Dn: number average particle diameter, Dv: volume average particle diameter, PDI: particle diameter distribution index.

(5) Measurement of oil absorption of linseed oil In order to evaluate the oil absorption of porous aliphatic polyester resin particles, Japanese Industrial Standard (JIS Standard) JIS K5101-13-1 2004 "Pigment test method Refined oil method" is used. It was. About 100 mg of porous aliphatic polyester resin fine particles was precisely weighed on a watch glass, purified linseed oil (manufactured by Kanto Chemical Co., Ltd.) was gradually added drop by drop with a burette, and was kneaded with a pallet knife. The dripping-kneading was repeated until a sample lump was formed, and the point where the paste became smooth hardness was taken as the end point. The oil absorption (ml / 100 g) was calculated from the amount of refined linseed oil used for dropwise addition.

Example 1
A poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH, Aonirex X131A made by Kaneka Co., Ltd.) Melted in a 1000 ml jacketed separable flask equipped with a cooling tube and a 3-one motor stirrer. Temperature: 112.2 ° C., 137.1 ° C., enthalpy of melting = 2.8 J / g, 23.9 J / g, SP value 21.3 (J / cm ³ ) ^1/2 ) 28 g, hydroxypropyl cellulose as polymer B Add 20 g of (Tokyo Chemical Industry Co., Ltd., weight average molecular weight 118,000, SP value 29.0 (J / cm ³ ) ^1/2 ), 352.0 g of ethyl acetoacetate as an organic solvent, and heat to 120 ° C. Stirring was performed until the polymer was completely dissolved. After the temperature of the system was returned to 70 ° C., 400 g of a 50% by mass aqueous ethanol solution as a poor solvent was added dropwise over 2 hours using a pump while stirring. After all the poor solvent had been added, the mixture was further stirred for 30 minutes. The obtained suspension was filtered and then washed with 200 g of ion exchanged water, and the filtered off was vacuum dried at 80 ° C. for 10 hours to obtain 26.7 g of a powdery white solid. When the obtained powder is observed by a scanning electron microscope, it has a porous fine particle shape, a volume average particle diameter of 40.6 μm, a number average particle diameter of 12.6 μm, and a particle diameter distribution index 3.2 The linseed oil absorption was 439 ml / 100 g of aliphatic polyester fine particles. The scanning electron micrograph of the obtained fine particles is shown in FIG. 1, and the particle size distribution is shown in FIG.

Claims (3)

Aliphatic polyester obtained from a bifunctional aliphatic hydroxycarboxylic acid having 4 or more carbon atoms, Aliphatic polyester obtained from an aliphatic dicarboxylic acid and / or an ester forming derivative thereof and an aliphatic diol and an aliphatic diol obtained from an aliphatic diol Polymer microparticles comprising an aliphatic polyester selected from the group consisting of: linseed oil absorption of at least 120 ml / 100 g and not more than 1000 ml / 100 g. Aliphatic polyester is represented by the formula (1): [-CHR ₁ -CH ₂ -CO-O-] (wherein R ₁ represents an alkyl group represented by C _n H _{2n + 1} , and n is an integer of 1 to 15) And R ₂ is not the same as R ₂ ), and a compound represented by the formula (2): [—CHR ₂ —CH ₂ —CO—O—] (wherein R ₂ is C _m H _{2m + 1} The polymer fine particle according to claim 1, which is an aliphatic polyester containing a repeating unit represented by the following formula: m is an integer of 1 to 15 and is not identical to R ₁ . The polymer particle according to claim 1 or 2, wherein an average particle size of the polymer particle is 1 to 1000 μm.