JP2004269865A - Production process of biodegradable resin particle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a process for production of spherical biodegradable resin particles with homogenous particle size distribution. <P>SOLUTION: The biodegradable resin particles are produced by preparation of a dispersion of a biodegradable resin component (A) and a water soluble adjuvant component (B) followed by elution of the adjuvant component (B). The biodegradable resin component (A) may be composed of a polyester resin such as an aliphatic polyester resin, a polyether resin, a vinyl alchol resin and a cellulose derivative. The adjuvant component (B) is composed of an oligosaccharide (B<SB>1</SB>) composed of tetroses and a water soluble plastisizer component (B<SB>2</SB>) to plastisize the oligosaccharide composed of sugars or a sugar alcohol. The weight ratio of the biodegradable resin component (A) and the adjuvant component (B) may be at 55/45 to 1/99 and the weight ratio of the oligosaccharide (B<SB>1</SB>) and the plastisizer component (B<SB>2</SB>) may be at 99/1 to 50/50. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a method for producing resin particles having biodegradability and useful as raw materials or additives in the field of fine chemicals such as agricultural chemicals, pharmaceuticals, cosmetics, paints, coatings, inks, and toners.

  Resin particles having biodegradability are excellent in biodegradability, for example, in the field used in the natural environment, in the field where recovery and reuse after use is difficult, in the field utilizing the special function of the resin, etc. Various production methods have been proposed that can be used usefully.

  Japanese Patent Application Laid-Open No. 2001-288273 (Patent Document 1) proposes a method of producing a polylactic acid-based resin fine powder by using a low-temperature pulverizer to pulverize at a low temperature of −50 to −180 ° C. . However, mechanical pulverization cannot not only obtain spherical fine particles, but also makes it difficult to narrow the distribution width of the particle diameter.

  JP-A-11-35693 (Patent Document 2) discloses a method in which a biodegradable polyester is dissolved in benzene, and then m-xylene is mixed at less than 60 ° C. to precipitate a biodegradable polyester powder. I have. However, this method not only requires a large amount of organic solvent, but also may cause the organic solvent to remain in the polymer.

  JP-A-10-176065 (Patent Document 3) discloses that a resin (a) is prepared by melt-kneading at least one other thermoplastic resin (b) into a finely-pulverized thermoplastic resin (a). Forms a dispersed phase, and forms a resin composition in which the resin (b) forms a continuous phase. The resin (a) does not dissolve, and the resin composition is washed with a solvent and conditions in which the resin (b) dissolves. Thus, a method for obtaining spherical fine particles of the resin (a) is disclosed.

  However, in this method, the resin to be pulverized must be excellent in solvent resistance. Further, not only the dispersed phase and the continuous phase need to be incompatible with each other, but also an appropriate combination of the resin of the continuous phase and the solvent needs to be selected depending on the type of the resin of the dispersed phase. Therefore, not only are the combinations of resins limited, but also the combinations of resins and solvents. Furthermore, in the process of cooling the dispersion, incompatible resins tend to cause large phase separation. Therefore, if this dispersion is not carefully solidified, the dispersed phase once formed is reassembled, and fine particles having a predetermined shape cannot be obtained. Furthermore, since the resin forming the continuous phase does not contribute to the resin fine particles to be a product at all, it is eventually recovered or discarded in a dissolved state. However, collecting the resin in the solution is not only very difficult but also increases the production cost of the resin fine particles. Further, when the resin solution is directly discarded as a waste liquid, there is a concern that the resin solution may have an adverse effect on the environment.

  JP-A-60-13816 (Patent Document 4) discloses that polyethylene glycol and a thermoplastic resin are melt-stirred and then poured into water to coagulate both polymers. A method for producing thermoplastic resin particles to be removed has been proposed. JP-A-61-9433 (Patent Document 5) discloses a method for producing thermoplastic resin particles in which a thermoplastic resin and polyethylene oxide are melted and stirred, then cooled, and the polyethylene oxide is removed using water. Have been. Further, Japanese Patent Application Laid-Open No. 9-165457 (Patent Document 6) discloses a melt-molded product obtained by mixing a melt-forming water-soluble polymer such as a polyvinyl alcohol-based resin, modified starch, or polyethylene oxide with a thermoplastic resin. A method for producing fine resin particles, wherein water-soluble polymers are removed from a molded product using water after the production is disclosed. In this document, polyethylene adipate and polybutylene adipate are described as thermoplastic resins.

However, these methods require incompatibility between the resin and the water-soluble polymer, which not only limits the type of the biodegradable resin but also ensures that the uniformity of the particle size distribution of the resin particles is sufficient. is not. Furthermore, since these water-soluble polymers have low solubility in water, a large amount of water is required for dissolution, and the dissolution rate is low, so that the productivity is significantly reduced. Furthermore, since such a water-soluble polymer is often derived from a non-natural product, a waste liquid in which such a water-soluble polymer is dissolved has an adverse effect on the environment.
JP 2001-288273 A JP-A-11-35693 JP-A-10-176065 JP-A-60-13816 JP-A-61-9433 JP-A-9-165457

  Accordingly, it is an object of the present invention to provide a method for producing a biodegradable resin particle in an industrially advantageous manner by efficiently eluting a water-soluble component using water.

  Another object of the present invention is to provide a method capable of producing biodegradable resin particles without being limited to compatibility or incompatibility between a biodegradable resin component and an auxiliary component.

  Still another object of the present invention is to provide a method capable of easily producing biodegradable resin particles regardless of solvent resistance.

  Another object of the present invention is to provide a production method capable of easily forming spherical particles using a biodegradable resin.

  Still another object of the present invention is to provide a production method capable of controlling the particle size of biodegradable resin particles and narrowing the distribution width of the particle size.

  Another object of the present invention is to provide a method for producing biodegradable resin particles that can reduce the load on the environment caused by a waste liquid.

  The present inventor has conducted intensive studies to achieve the above object, and as a result, when forming a dispersion by combining at least an auxiliary component composed of an oligosaccharide with a biodegradable resin component, the auxiliary component is formed using water. The present inventors have found that it is possible to efficiently elute, reduce the burden on the environment, and easily produce spherical biodegradable resin particles, and thus completed the present invention.

That is, the method for producing biodegradable resin particles of the present invention comprises a biodegradable resin component (A) and a water-soluble auxiliary component (B) containing at least an oligosaccharide (B ₁ ). The water-soluble auxiliary component (B) is eluted from the dispersion in which the resin component (A) is dispersed in the form of particles. The biodegradable resin particles may be spherical. The biodegradable resin component (A) may be composed of a polyester resin, a polyether resin, a vinyl alcohol resin, a cellulose derivative, or the like. The biodegradable resin component (A) is a unit (a) represented by the following formula:
—OC—R ¹ —CO— (a)
(Wherein, R ¹ represents a direct bond or a divalent aliphatic hydrocarbon group which may have a substituent)
And a unit (b) represented by the following formula:
—OR ² —O— (b)
(Wherein, R ² represents a divalent aliphatic hydrocarbon group which may have a substituent)
An aliphatic polyester resin (A ₁ ) composed of
Unit (c) represented by the following formula
—OR ³ —CO— (c)
(Wherein, R ³ represents a divalent aliphatic hydrocarbon group which may have a substituent)
In configuration aliphatic polyester resin (A _2), and be configured with at least one of said units (a) and (b) and (c) a de-configured aliphatic polyester resin (A ₃₎ Good. The biodegradable resin component (A) can usually be composed of at least an aliphatic polyester resin, and may be composed of an aliphatic polyester resin and an aromatic polyester resin. The oligosaccharide (B ₁ ) may exhibit a melting point or softening point at a temperature higher than the heat deformation temperature of the resin component (A), or may decompose. For example, the melting point or softening point of the oligosaccharide (B ₁ ) may be higher than the heat deformation temperature of the resin component (A), for example, about 90 to 290 ° C. Further, the oligosaccharide (B ₁ ) may be an oligosaccharide which is thermally decomposed at a temperature higher than the thermal deformation temperature of the resin component (A) without showing a clear melting point or softening point. The heat distortion temperature of the resin may be measured, for example, as a Vicat softening point specified in JIS K 7206, and the heat distortion temperature (Vicat softening point) of the resin is, for example, 60 to 300 ° C, preferably 80 to 260 ° C. It may be about ° C. The oligosaccharide (B ₁ ) may be composed of at least a tetrasaccharide. Further, the oligosaccharide (B ₁ ) may be composed of an oligosaccharide composition such as starch sugar, galacto-oligosaccharide, coupling sugar, fructooligosaccharide, xylo-oligosaccharide, soybean oligosaccharide, chitin oligosaccharide, chitosan oligosaccharide, The content of the tetrasaccharide in such an oligosaccharide (B ₁ ) may be 60% by weight or more. The viscosity of the 50% by weight aqueous solution of the oligosaccharide (B ₁ ) may be 1 Pa · s or more (for example, about 3 to 100 Pa · s) when measured with a B-type viscometer at 25 ° C.

Further, the auxiliary component (B) may contain a water-soluble plasticizing component (B ₂ ) for plasticizing the oligosaccharide (B ₁ ). When the oligosaccharide (B ₁ ) and the plasticizing component (B ₂ ) are combined, even if the oligosaccharide (B ₁ ) is a thermally decomposable oligosaccharide, it can be effectively plasticized or softened. The melting point or softening point of the plasticizing component (B ₂ ) may be lower than the heat deformation temperature (Vicat softening point) of the resin component (A). When the melt flow rate specified by JIS K 7210 was measured at a temperature 30 ° C. higher than the heat deformation temperature of the resin component (A), the resin component (A) was composed of the oligosaccharide (B ₁ ) and the plasticizing component (B ₂ ). The melt flow rate of the auxiliary component (B) may be, for example, 1 or more (for example, about 1 to 40). The plasticizing component (B ₂ ) may be composed of a saccharide (eg, a monosaccharide, a disaccharide, etc.) or a sugar alcohol (eg, erythritol, pentaerythritol, arabitol, ribitol, xylitol, sorbitol, dulcitol, mannitol, etc.). Good. The ratio (weight ratio) of the biodegradable resin component (A) and the auxiliary component (B) is such that the resin component (A) / the auxiliary component (B) = 55/45/1/99 (preferably, 50 / 50-5 / 95). In the auxiliary component (B), the ratio (weight ratio) of the oligosaccharide (B ₁ ) to the plasticizing component (B ₂ ) is ₁ ) / Plasticizing component (B ₂ ) may be about 99/1 to 50/50 (preferably 95/5 to 60/40).

  The present invention also includes biodegradable resin particles produced by the above production method. The biodegradable resin particles may be spherical. The average particle diameter of the biodegradable resin particles may be 0.1 to 100 μm, and the coefficient of variation of the average particle diameter may be 60 or less. The number average molecular weight of the biodegradable resin particles may be 250,000 or less (for example, about 2,000 to 250,000). Further, the biodegradable resin particles do not substantially contain a water-soluble auxiliary component, and for example, contain 3% by weight or less of a water-soluble auxiliary component based on the whole particles.

  In the present invention, the biodegradable resin component may be referred to as “resin component”, and the water-soluble auxiliary component may be referred to as “auxiliary component”. The term “spherical” is not limited to a true sphere, and the ratio of the major axis to the minor axis is such that the major axis / minor axis = 1.5 / 1 to 1/1 (preferably 1.2 / 1 to 1/1, more preferably 1/1). . 1/1 to 1/1).

  In the present invention, a biodegradable resin particle can be industrially advantageously produced because a water-soluble auxiliary component having a high elution property to water is used. Further, since a water-soluble auxiliary component containing at least an oligosaccharide is used, regardless of the compatibility and incompatibility between the biodegradable resin component and the water-soluble auxiliary component, the biodegradable resin component and the water-soluble auxiliary component are used. And a biodegradable resin component having low solvent resistance can be used. Furthermore, in the production method of the present invention, not only can the spherical biodegradable resin particles be produced simply, but also the particle diameter can be controlled and the distribution width of the particle diameter can be narrowed. Furthermore, since the water-soluble auxiliary component of the present invention is a component derived from a natural product, the burden on the environment can be reduced.

  The method of the present invention comprises a step of preparing a dispersion composed of a biodegradable resin component (A) and a water-soluble auxiliary component (B), and a step of eluting the water-soluble auxiliary component from the dispersion. ing.

[Step of preparing dispersion]
(Biodegradable resin component (A))
The resin constituting the biodegradable resin component is not particularly limited as long as it is a biodegradable resin, and may be a naturally produced biodegradable resin or a chemically synthesized biodegradable resin. The biodegradable resin is preferably poorly water-soluble, particularly preferably water-insoluble.

  The heat distortion temperature of the resin component (e.g., the Vicat softening point defined by JIS K 7206) can be selected from the range of 60 to 300C, for example, 80 to 260C, preferably 100 to 240C (for example, 110 to 240C). ° C), and more preferably about 120 to 230 ° C (eg, 130 to 220 ° C).

Examples of the biodegradable resin component include polysaccharides (eg, cellulose derivatives such as cellulose and low-substituted cellulose ester, higher fatty acid esterified wood, lignin, starch, polygalactosamine, alginic acid, carrageenan, β-1,3). -Curdlan, pullulan, chitin, chitosan, xanthan, dextran, etc., composed of glucan, denatured protein [for example, denatured wheat gluten (glycerin, glycol, emulsified silicone oil, urea, etc. added to wheat gluten) Modified resins, etc.), polyester resins (aliphatic polyester resins, etc.), vinyl alcohol resins (polyvinyl alcohol, ethylene-vinyl alcohol copolymer, etc.), polyether resins (polyoxyethylene glycol, polyoxypropylene) Glycol, po Oxytetramethylene glycol), polyamide resins such as (low molecular weight nylon, aliphatic polyurethane amide), polyamino acid resin (poly (.gamma.-glutamic acid), etc.) can be exemplified. As long as the biodegradability is not suppressed, a biodegradable resin and a non-biodegradable resin (polyolefin resin, polyamide resin, polystyrene resin, (meth) acrylic resin, aromatic polyester resin, etc.) May be combined to form a biodegradable resin component. These biodegradable resin components can be used alone or in combination of two or more. Among these biodegradable resin components, cellulose derivatives, polyester-based resins, polyether-based resins, vinyl alcohol-based resins, and the like are preferable in terms of water resistance, processability, cost, mechanical properties, and the like.
(1) Cellulose Derivatives Cellulose derivatives include cellulose esters, cellulose carbamates (such as cellulose phenyl carbamate), and cellulose ethers. These cellulose derivatives can be used alone or in combination of two or more.

  Examples of the cellulose esters include organic acid esters such as cellulose acetate (cellulose acetate) such as cellulose diacetate and cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate propionate, cellulose acetate butyrate, and cellulose phthalate. (Or acyl cellulose); inorganic acid esters such as cellulose nitrate, cellulose sulfate and cellulose phosphate; mixed acid esters such as cellulose nitrate acetate;

Examples of the cellulose ethers include alkyl cellulose (for example, C _1-6 alkyl cellulose such as methyl cellulose, ethyl cellulose, isopropyl cellulose, and butyl cellulose), aralkyl cellulose (for example, benzyl cellulose), and hydroxyalkyl cellulose (for example, hydroxyethyl cellulose). , hydroxypropyl cellulose, hydroxypropyl C _2-6 alkyl celluloses such as hydroxybutyl cellulose), hydroxyalkyl alkylcelluloses (e.g., hydroxyethyl cellulose, hydroxypropyl C _2-4 alkyl C _1-6 alkyl celluloses such as hydroxypropyl methylcellulose), carboxy alkylcelluloses (e.g., carboxy C _1-6 alkyl cell row including carboxymethyl cellulose ), And cyanoethyl cellulose and the like.

  The average degree of substitution of the cellulose derivative can be selected from the range of about 0.1 to 3 (preferably 0.3 to 3, more preferably 0.5 to 3) depending on the type of cellulose. Cellulose esters may have, for example, an average degree of substitution of 1 to 3, preferably about 2 to 3, and cellulose ethers have, for example, an average degree of substitution of 0.3 to 2.5, preferably 0.5 to 2 (for example, 0.5 to 1.5). From the viewpoint of biodegradability, the degree of substitution of the cellulose derivative is preferably low.

  In addition, the viscosity average degree of polymerization of the cellulose derivative can be appropriately selected depending on the type of the resin within a range that does not impair biodegradability, and is, for example, 50 to 800, preferably 75 to 500, and more preferably 100 to 250 (for example, 100-200).

The viscosity-average degree of polymerization of the cellulose derivative can be measured by the limiting viscosity method of Uda et al. (Uda Kazuo, Saito Hideo, Journal of the Textile Society, Vol. 18, No. 1, pp. 105-120, 1962).
(2) Polyester resin The polyester resin is roughly classified into an aromatic polyester resin and an aliphatic polyester resin, and is usually composed of at least an aliphatic polyester resin from the viewpoint of biodegradability. The aliphatic polyester-based resin includes an aliphatic polyester-based resin (A ₁ ) composed of a unit (a) corresponding to an aliphatic dicarboxylic acid and a unit (b) corresponding to an aliphatic diol, oxycarboxylic acid or lactone. Aliphatic polyester resin (A ₂ ) composed of a unit (c) corresponding to the above, and aliphatic polyester resin (A ₃ ) composed of the units (a), (b) and (c) Is included. These aliphatic polyester resins can be used alone or in combination of two or more.

  The unit (a) corresponding to the aliphatic dicarboxylic acid is represented by the following formula.

—OC—R ¹ —CO— (a)
(In the formula, R ¹ represents a direct bond or a divalent aliphatic hydrocarbon group which may have a substituent.)
Examples of the divalent aliphatic hydrocarbon group represented by R ¹ include linear or branched aliphatic hydrocarbon groups [for example, methylene, ethylene, trimethylene, propylene, isopropylene, butylene, t-butylene, pentylene, hexylene, A C _1-12 alkylene group such as an octylene group (preferably a C _1-10 alkylene group, more preferably a C _1-8 alkylene group)], an alicyclic hydrocarbon group [eg, cyclopentylene, cyclohexylene, cyclo A C _3-20 cycloalkylene group (preferably a C _5-12 cycloalkylene group) such as octylene and cyclodecylene group]. The divalent aliphatic hydrocarbon group may contain a hetero atom such as oxygen, nitrogen or sulfur atom as a constituent atom of the chain. The units (a) corresponding to these aliphatic dicarboxylic acids can be used alone or in combination of two or more.

The aliphatic hydrocarbon group may have various substituents, for example, a substituent that is generally inactive in an ester reaction or a transesterification reaction. Examples of the substituent include an alkyl group [eg, a C _1-6 alkyl group such as a methyl or ethyl group (preferably a C _1-4 alkyl group, more preferably a C _1-3 alkyl group)], a cycloalkyl Groups [eg, C _3-10 cycloalkyl groups (preferably C _3-8 cycloalkyl groups, more preferably C _3-6 cycloalkyl groups) such as cyclopentyl, cyclohexyl, cyclooctyl, and cyclodecyl groups], and alkoxy groups [ For example, a C _1-6 alkoxy group such as methoxy and ethoxy (preferably a C _1-4 alkoxy group) and the like, and an oxo group.

Examples of the compound corresponding to R ¹ include an aliphatic dicarboxylic acid or a reactive derivative thereof (an acid anhydride, a C _1-3 alkyl ester, an acid halide such as an acid chloride, and the like). As the aliphatic dicarboxylic acid, for example, a linear or branched aliphatic dicarboxylic acid [eg, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, A linear or branched aliphatic dicarboxylic acid having about 2 to 14 carbon atoms such as dodecane diacid (preferably a linear aliphatic dicarboxylic acid having 2 to 10 carbon atoms, more preferably a linear aliphatic dicarboxylic acid having 2 to 8 carbon atoms) Linear aliphatic dicarboxylic acids, particularly oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid), etc.], alicyclic dicarboxylic acids (eg, cyclohexanedicarboxylic acid, hexahydrophthalic acid, hexahydroisophthalic acid, hexahydroacid) Alicyclic dicarboxylic acids having about 8 to 14 carbon atoms, such as terephthalic acid and hymic acid), diglycolic acid, ketopimeric acid, etc. Kiso alkylene dicarboxylic acid, and alkyl (e.g. C _1-6 alkyl) substituents of these dicarboxylic acids.

  The unit (b) corresponding to the diol is represented by the following formula.

—OR ² —O— (b)
(Wherein, R ² represents a divalent aliphatic hydrocarbon group which may have a substituent)
Examples of the divalent aliphatic hydrocarbon group represented by R ² include the divalent aliphatic hydrocarbon groups which may have a substituent described above for R ¹ . The units (b) corresponding to these diols can be used alone or in combination of two or more. As the substituent, various substituents such as exemplified substituents wherein R ¹ can be mentioned.

Examples of the compound corresponding to the unit (b) include aliphatic diols such as ethylene glycol, trimethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2-methylpropanediol, and neopentyl glycol. Alkanediols having 2 to 12 carbon atoms (preferably alkanediols having 2 to 8 carbon atoms, more preferably 2 to 6 carbon atoms), such as pentamethylene glycol, hexamethylene glycol, octamethylene glycol, decamethylene glycol, dodecamethylene glycol and the like. Alkanediols, in particular, ethylene glycol, propylene glycol, 1,4-butanediol), cycloalkanediols having 5 to 12 carbon atoms such as 1,4-cyclohexanediol and 1,4-cyclohexanedimethanol Le, polyoxy C _2-4 alkanediols having oxyalkylene units [such as diethylene glycol, triethylene glycol, dipropylene glycol, polytetramethylene ether glycol, etc.] and the like.

Specifically, the polyester resin (A ₁ ) includes, for example, a polyester resin in which R ¹ of the unit (a) is a direct bond and R ^{2 of the} unit (b) is a C _1-12 alkylene group ( For example, polyester resins formed by the reaction of oxalic acid and C _2-8 alkanediol, for example, poly C _2-6 alkylene oxolates such as polyethylene oxalate, polybutylene oxalate, and _{polyneopentyl} oxalate Polyester resin in which R ¹ of the unit (a) is a C _1-12 alkylene group and R ² of the unit (b) is a C _1-12 alkylene group (for example, C _1-8 alkylene dicarboxylic acid). Polyester resins formed by the reaction of an acid with a C _2-8 alkanediol, for example, poly C _2-6 alkylene malonate such as polyethylene malonate and polybutylene malonate G; poly C _2-6 alkylene succinate such as polyethylene succinate, polybutylene succinate, polyneopentyl succinate; poly C _2-6 alkylene adipate such as polyethylene adipate, polybutylene adipate, polyneopentyl adipate, etc. ), A polyester resin in which the unit (a) is composed of a plurality of units and R ² of the unit (b) is a single or plural C _1-12 alkylene group [for example, oxalic acid and C _1-8 alkylene dicarboxylic acid Polyester resins formed by the reaction of a plurality of dicarboxylic acids selected from acids with at least one diol selected from C _2-8 alkanediols, for example, poly (ethylene-oxalate-malonate) copolymer resins, (Butylene-oxalate-malonate) copolymer resin Poly (C _2-6 alkylene - oxalate - malonate) copolymer resin, poly (ethylene - oxalate - succinate) copolymer resin, poly (butylene - oxalate - succinate) such as a copolymer resin poly (C _2-6 alkylene - oxalates Poly (ethylene-succinate-adipate) copolymer resin, poly (C _2-6 alkylene-succinate-adipate) copolymer resin such as poly (butylene-succinate-adipate) copolymer resin], A polyester resin in which R ^{1 of the} unit (a) is a direct bond and R ² of the unit (b) is a C _3-20 cycloalkylene group (for example, by the reaction of oxalic acid with a C _3-12 cycloalkanediol) Polyester resin produced, for example, polycyclopropylene oxalate, polycyclo Poly C _3-10 cycloalkylene o Giza rates such as xylene o Giza rate), R ¹ of the unit (a) is a C _1-12 alkylene group, R ² is C _3-20 cycloalkylene group unit (b) (Eg, a polyester resin formed by the reaction of a C _1-8 alkylenedicarboxylic acid with a C _5-12 cycloalkanediol, for example, a poly C _5-10 cycloalkylene succinate such as polycyclohexylene succinate) And polyester-based resins such as poly (C _5-10 cycloalkylene adipate such as polycyclohexylene adipate).

The polyester-based resin (A ₁ ) contains the unit (a) and the unit (b) as main components [for example, 50 mol% or more (for example, the units (a) and (b) are 50 to 98 mol%). , Preferably about 70 to 95 mol%, more preferably about 80 to 95 mol%], and is not limited to a homopolyester, and may be a copolyester containing a copolymer component. Examples of the copolymerization component include aromatic dicarboxylic acids [eg, terephthalic acid, isophthalic acid, phthalic acid; alkyl-substituted phthalic acids such as methyl terephthalic acid and methyl isophthalic acid; naphthalenedicarboxylic acid (2,6-naphthalenedicarboxylic acid, 2,2 7-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, etc.); diphenyldicarboxylic acid (for example, 4,4'-diphene) Diphenyl ether dicarboxylic acid (eg, diphenyl ether-4,4′-dicarboxylic acid); diphenyl alkane dicarboxylic acid (eg, diphenyl methane dicarboxylic acid, diphenyl ethane dicarboxylic acid, etc.); carbon number of diphenyl ketone dicarboxylic acid, etc. Aromatic dicarboxylic acid having about 8 to 20], long-chain aliphatic dicarboxylic acid (for example, aliphatic dicarboxylic acid having about 15 to 40 carbon atoms such as hexadecanedicarboxylic acid and dimer acid), aromatic diol (for example, resorcinol) , Hydroquinone, naphthalene diol, bisphenols such as bisphenol A, F, and AD, aromatic diols having about 6 to 20 carbon atoms such as alkylene oxide adducts of bisphenols), and long-chain aliphatic diols (for example, hexene). Examples thereof include aliphatic diols having about 13 to 40 carbon atoms, such as decanediol, and aromatic oxycarboxylic acids (for example, aromatic oxycarboxylic acids having 6 to 20 carbon atoms, such as hydroxybenzoic acid and oxynaphthoic acid). These copolymer components can be used alone or in combination of two or more.

  The unit (c) corresponding to oxycarboxylic acid or lactone is represented by the following formula.

—OR ³ —CO— (c)
(Wherein, R ³ represents a divalent aliphatic hydrocarbon group which may have a substituent)
Examples of the divalent aliphatic hydrocarbon group represented by R ³ include the divalent aliphatic hydrocarbon groups which may have a substituent described above for R ¹ . The unit (c) can be used alone or in combination of two or more. As the substituent, various substituents such as exemplified substituents wherein R ¹ can be mentioned.

Examples of the compound corresponding to the unit (c) include oxycarboxylic acid or a reactive derivative thereof (acid anhydride, C _1-3 alkyl ester, acid halide such as acid chloride), for example, oxyaliphatic carboxylic acid [eg, Oxycarboxylic acids having about 2 to 11 carbon atoms, such as glycolic acid, lactic acid, malic acid, oxypropionic acid, and oxybutyric acid (preferably, oxycarboxylic acids having 2 to 9 carbon atoms, more preferably oxycarboxylic acids having 2 to 6 carbon atoms) Carboxylic acids), oxyalicyclic carboxylic acids (eg, hydroxycyclohexanecarboxylic acids), alkyl (eg, C _1-6 alkyl) -substituted oxycarboxylic acids, etc .; lactones [eg, propiolactone, butyrolactone, δ-valerolactone, γ-valerolactone, caprolactone, 1,3-dioxolan-4-one 1,4-dioxane-3-one, 1,5-dioxepan-2-one may lactones have a number 3 to 13 degree of the oxygen atoms of carbon, such as (preferably C _4-11 lactone, and more preferably Is C _4-9 lactone, especially C _4-7 caprolactone such as ε-caprolactone); glycolide, 1,5-dioxacyclooctane-2,6-dione, dilactide (L-lactide, D-lactide) and the like Lactides having 4 to 8 carbon atoms (preferably glycolide, dilactide, etc.)] and the like. When the oxycarboxylic acid contains an optically active form or a racemic form (D form, L form, DL form), any of them may be used.

Specifically, the polyester-based resin (A ₂ ) includes, for example, a polyester-based resin in which R ³ is a C _1-12 alkylene group derived from a _{polyoxycarboxylic} acid in the unit (c) [for example, having 1 to 8 carbon atoms] oxycarboxylic acids (hydroxy C _1-8 alkanecarboxylic - carboxylic acid) than obtained polyester resin (e.g., polyglycolic acid, polylactic acid, such as polymalic acid (hydroxy C _1-8 alkanecarboxylic - carboxylic acid), etc.); A polyester-based resin (for example, a poly (glycolic acid-lactic acid) copolymer resin or the like) formed by a reaction of a plurality of hydroxy C _1-8 alkane-carboxylic acids], wherein the unit (c) is the lactone and / or the lactide polylactone resins [for example produced by ring-opening polymerization, a polyester resin obtained from C _3-12 lactones (e.g., Porikapu Lactone (manufactured by Daicel Chemical Industries, Ltd., PCLH7, PCLH4, PCLH1 etc.) poly C _3-12 lactones such as; C _3-12 polyester resins obtained from lactides (e.g., poly C _3-12 lactide such as polylactide ), A polyester-based resin (for example, a poly (lactide-glycolide) copolymer resin or the like) formed by ring-opening polymerization of a plurality of the lactones and / or a plurality of the lactides, etc., and a reaction between oxycarboxylic acid and lactone. And the like.

The polyester resin (A ₂ ) contains a unit (c) corresponding to oxycarboxylic acid or lactone as a main component [for example, 50 mol% or more (for example, 50 to 98 mol%, preferably 70 to 95 mol%, More preferably, about 80 to 95 mol%], not limited to a homopolyester, but may be a copolyester containing a copolymer component. Examples of the copolymer component exemplified in the resin (A ₁ ) (eg, aromatic dicarboxylic acid, long-chain aliphatic dicarboxylic acid, aromatic diol, long-chain aliphatic diol, aromatic oxycarboxylic acid, etc.).

Further, the aliphatic polyester-based resin may be an aliphatic polyester-based resin (A ₃ ) composed of the units (a), (b) and (c). Specifically, an aliphatic polyester resin in which the unit (c) is derived from an oxycarboxylic acid, for example, a polyester formed by a reaction of oxalic acid, C _2-8 alkanediol and hydroxy C _1-8 alkane-carboxylic acid -Based resins [for example, poly (hydroxy C _1-8 alkane-carboxylic acid-C _2-4 alkylene-oxalate) such as poly (glycolic acid-butylene-oxalate) copolymer resin and poly (lactic acid-butylene-oxalate) copolymer resin ) Copolymer resins, etc.], and polyester resins [eg, poly (glycolic acid)] formed by the reaction of hydroxy C _1-8 alkane-carboxylic acid, C _2-6 alkane diol and hydroxy C _1-8 alkane-carboxylic acid. Poly (hydroxy) such as butylene-malonate copolymer resin and poly (lactic acid-butylene-malonate) copolymer resin (C _1-8 alkane-carboxylic acid-C _2-4 alkylene-malonate) copolymer resin; poly (glycolic acid-butylene-succinate) copolymer resin, poly (lactic acid-butylene-succinate) copolymer resin, etc. Hydroxy (C _1-8 alkane-carboxylic acid-C _2-4 alkylene-succinate) copolymer resin; poly (glycolic acid-butylene-adipate) copolymer resin, poly (lactic acid-butylene-adipate) copolymer resin, etc. Hydroxy C _1-8 alkane-carboxylic acid-C _2-4 alkylene-adipate) copolymer resin, and an aliphatic polyester-based resin in which the unit (c) is derived from lactone, for example, oxalic acid and C _2-8 alkanediol a C _4-10 polyester resin formed by the reaction with the lactone [e.g., poly (caprolactone - butylene - oxalates) Copolymer resin, poly (glycolide - butylene - oxalate) copolymer resin, poly (lactide - butylene - oxalate), such as a copolymer resin poly (C _4-10 lactone -C _2-4 alkylene - oxalate) copolymer resin, etc.], Polyester resin produced by the reaction of C _1-8 alkylenedicarboxylic acid, C _2-6 alkanediol and C _4-10 lactone [for example, poly (caprolactone-butylene-malonate) copolymer resin, poly (glycolide-butylene- Poly (C _4-10 lactone-C _2-4 alkylene-malonate) copolymer resin such as malonate) copolymer resin and poly (lactide-butylene-malonate) copolymer resin; poly (caprolactone-butylene-succinate) copolymer resin Poly (glycolide-butylene-succinate) copolymer resin, poly (lactide-butylene) Succinate) such as a copolymer resin poly (C _4-10 lactone -C _2-4 alkylene - succinate) copolymer resin, poly (caprolactone - butylene - adipate) copolymer resin, poly (glycolide - butylene - adipate) copolymer resin And a poly (C _4-10 lactone-C _2-4 alkylene-adipate) copolymer resin such as a poly (lactide-butylene-adipate) copolymer resin].

The polyester-based resin (A ₃ ) contains units (a) to (c) as a main component [for example, 50 mol% or more [for example, the units (a), (b), and (c) are 50 to 98%). Mol%, preferably about 70 to 95 mol%, more preferably about 80 to 95 mol%], and may be a copolyester containing a copolymer component. Among the main component, the concentration of units derived from such a hydroxycarboxylic acid or lactone (c), the polyester-based resin (A _3), 0.01 to 30 mol% (e.g., 0.02 to 30 mol%) , Preferably 0.02 to 25 mol% (for example, 0.02 to 20 mol%), more preferably 0.5 to 20 mol% (for example, 1 to 20 mol%), and particularly about 1 to 15 mol%. There may be.

Examples of the copolymer component include the copolymer components exemplified in the polyester resin (A ₁ ) (for example, aromatic dicarboxylic acid, long-chain aliphatic dicarboxylic acid, aromatic diol, long-chain aliphatic diol, aromatic oxycarboxylic acid) Etc.).

  Note that a branched structure may be introduced into the polyester resin using a small amount of a polyfunctional compound. Examples of polyfunctional compounds include, for example, polycarboxylic acids (eg, tricarboxylic acids), polyols (eg, glycerin, triols such as trimethylolpropane, tetraols, etc.), and polyfunctional hydroxy-carboxylic acids (eg, tartaric acid, Gallic acid, citric acid, etc.).

Further, the polyester-based resins (A ₁ ), (A ₂ ) and (A ₃ ) are modified with bisalkyl carbonates (for example, di C _2-4 alkyl carbonate such as dimethyl carbonate) and bisaryl carbonates (for example, , Di C _6-12 aryl carbonate such as diphenyl carbonate), C _4-10 alkylenediamine (eg, tetramethylene diamine, hexamethylene diamine, etc.), carbonyl halide (eg, carbonyl chloride, etc.), diisocyanate (eg, aromatic diisocyanate) (Eg, phenylene diisocyanate, tolylene diisocyanate, diphenylmethane-4,4′-diisocyanate), araliphatic diisocyanate (eg, xylylene diisocyanate), alicyclic diisocyanate (eg, Isophorone diisocyanate), aliphatic diisocyanate (for example, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, lysine diisocyanate methyl ester, trimethylhexamethylene diisocyanate, and the like, preferably hexamethylene diisocyanate), and the like. Good. These modifying components can be used alone or in combination of two or more.

  Specific examples of the modified polyester resin include a polyester resin containing a urethane bond (for example, “Bionole 1000”, “Bionole 3000”, “Bionole 6000”, etc., manufactured by Showa Kogaku KK). And polyester polyether copolymer resins, polyester carbonate copolymer resins, polyester amide copolymer resins, and the like.

  In addition, these polyester-based resins may be a naturally produced biodegradable resin [for example, a microorganism-produced biodegradable resin (for example, poly (3-hydroxybutyric acid), etc.)], and a chemically synthesized biodegradable resin. Resin may be used.

  The number average molecular weight of the aliphatic polyester-based resin can be appropriately selected depending on the type of the resin within a range that does not impair biodegradability. For example, the number average molecular weight by gel permeation chromatography is 2,000 to 300 in terms of polystyrene. , Preferably about 5,000 to 200,000, and more preferably about 10,000 to 150,000.

In order to improve the rigidity, the aliphatic polyester-based resins (A ₁ ) to (A ₃ ) include aromatic polyester-based resins (for example, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), etc.). _2-4 alkylene terephthalate; poly C _2-4 alkylene naphthalate corresponding to this polyalkylene terephthalate (eg, polyethylene naphthalate); homopolyester or copolyester such as 1,4-cyclohexyl dimethylene terephthalate (PCT) Etc.) may be combined. In the combination with the aromatic polyester resin, the aliphatic polyester resin includes the biodegradable resin (for example, poly C _1-4 alkylene oxalate such as polyethylene oxalate, poly C ₁ such as polyethylene succinate). _-4 alkylene succinate, polyglycolic acid, polylactic acid, etc.). Of these aliphatic polyester resins, at least polylactic acid is often used.

  The ratio (weight ratio) of the aliphatic polyester resin and the aromatic polyester resin is as follows: aliphatic polyester resin / aromatic polyester resin = 99/1 to 60/40, preferably 99/1 to 70/30, More preferably, it may be about 99/1 to 80/20. The above ratio can be applied to an aliphatic polyester resin having an aromatic component (eg, an aromatic dicarboxylic acid or an aromatic diol) as a copolymer component.

  Usually, the biodegradability of the biodegradable resin component can be improved by increasing the proportion of the aliphatic polyester resin. Biodegradability can also be promoted by reducing the molecular weight of the aliphatic polyester-based resin. The number average molecular weight (in terms of polystyrene) of the aliphatic polyester-based resin (for example, polylactic acid) is, for example, 300,000 or less (for example, about 2,000 to 250,000), preferably 200,000 or less (for example, 3 or less). 5,000 to 150,000), more preferably 150,000 or less (for example, about 5,000 to 100,000).

(3) Polyether resin As the polyether resin, polyoxyalkylene resins (for example, polyoxymethylene glycol, polyoxyethylene glycol, polyoxypropylene glycol, polyoxytetramethylene glycol, polyoxyethylene-polyoxypropylene) And polyoxy C _1-4 alkylene glycols such as block copolymers). These polyether resins can be used alone or in combination of two or more.

  The number average molecular weight of the polyether-based resin can be appropriately selected depending on the type of the resin within a range that does not impair biodegradability, and is, for example, 1,000 to 100,000, preferably 2,000 to 50,000, and furthermore Preferably, it may be about 5,000 to 20,000.

Among these polyether resins, water-soluble polyoxyethylene glycol and polyoxyethylene-polyoxypropylene block copolymers have a high molecular weight (for example, a number average molecular weight of 2,000 or more) from the viewpoint of water resistance. (For example, about 2,000 to 100,000), preferably 4,000 or more (for example, about 4,000 to 90,000), and more preferably 6,000 or more (for example, about 6,000 to 80,000). is there. Further, in order to make the water-soluble polyether-based resin hardly water-soluble (particularly water-insoluble), these polyether-based resins are saturated aliphatic monocarboxylic acids (for example, C _1-4 such as acetic acid and butyric acid). And an alkyl carboxylic acid).

(4) Vinyl alcohol-based resin As the vinyl alcohol-based resin, derivatives of vinyl ester-based resin, for example, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polyvinyl acetal-based resin (for example, polyvinyl formal-based resin, polyvinyl butyral-based resin) Etc.). These vinyl alcohol resins can be used alone or in combination of two or more.

  In polyvinyl alcohol, in order to achieve both water resistance and biodegradability, the degree of saponification can be selected from the range of 10 to 80%, preferably 20 to 70%, more preferably about 30 to 50%. .

  The number average molecular weight of the vinyl alcohol-based resin can be appropriately selected depending on the type of the resin within a range that does not impair biodegradability, and is, for example, 1,000 to 500,000, preferably 5,000 to 300,000 (for example, , 10,000 to 200,000), and more preferably about 10,000 to 150,000 (for example, 30,000 to 100,000). The average degree of polymerization of the vinyl alcohol-based resin can be selected from the above range of molecular weight, and may be, for example, about 500 to 5,000, preferably about 1,000 to 2,500.

(Water-soluble auxiliary component)
The water-soluble auxiliary component (B) is composed of at least an oligosaccharide (B ₁ ), and is eluted after forming a dispersion in combination with a biodegradable resin component. In order to adjust the heat melting properties of the oligosaccharide, the water-soluble auxiliary preferably further comprises a plasticizing component (B ₂ ).

(1) Oligosaccharide (B ₁ )
The oligosaccharide (B ₁ ) is composed of a homooligosaccharide in which 2 to 10 molecules of a monosaccharide are dehydrated and condensed via a glycosidic bond, and at least two or more monosaccharides and / or sugar alcohols having a 2 to 10 molecular glycosidic bond. And hetero-oligosaccharides that have been dehydrated and condensed through The oligosaccharide (B ₁ ) includes, for example, disaccharide to decasaccharide, and usually disaccharide to hexasaccharide oligosaccharide is used. Oligosaccharides are usually solid at room temperature. In addition, these oligosaccharides may be anhydrous. In the oligosaccharide, a monosaccharide and a sugar alcohol may be bonded. These oligosaccharides can be used alone or in combination of two or more. The oligosaccharide may be an oligosaccharide composition composed of a plurality of sugar components. Even such an oligosaccharide composition may be simply referred to as an oligosaccharide.

  Examples of the disaccharide include trehalose (eg, α, α-trehalose, β, β-trehalose, α, β-trehalose, etc.), kojibiose, nigerose, maltose, isomaltose, sophorose, laminaribiose, cellobiose, gentiobiose and the like. And heterooligosaccharides such as lactose, sucrose, palatinose, melibiose, rutinose, primeverose, and turanose.

  Examples of the trisaccharide include homooligosaccharides such as maltotriose, isomalttriose, panose, and cellotriose; and heterooligosaccharides such as manninotriose, solatriose, melezitose, planteose, gentianose, umbelliferose, and raffinose.

  Examples of the tetrasaccharide include homo-oligosaccharides such as maltotetraose and isomalttetraose; and heterooligosaccharides such as stachyose, cellotetraose, scorodose, liquinose, and panose in which a sugar or sugar alcohol is bonded to the reducing end of panose.

  Among these tetrasaccharides, tetraose in which a monosaccharide or a sugar alcohol is bonded to the reducing end of panose is disclosed in, for example, JP-A-10-215892, and glucose, fructose, mannose, Examples include monosaccharides such as xylose and arabinose, and tetraose to which sugar alcohols such as sorbitol, xylitol and erythritol are bound.

  Examples of pentasaccharides include homooligosaccharides such as maltopentaose and isomaltopentaose; and heterooligosaccharides such as pentaose in which a disaccharide is bonded to the reducing end of panose.

  Pentaose in which a disaccharide is bound to the reducing end of panose is also disclosed in, for example, JP-A-10-215892, and pentaose in which a disaccharide such as sucrose, lactose, cellobiose, and trehalose is bound to the reducing end of panose. Can be illustrated.

  Hexasaccharides include homooligosaccharides such as maltohexaose and isomaltohexaose.

  The oligosaccharide is preferably composed of at least a tetrasaccharide from the viewpoint of melt kneading with the resin component.

  The oligosaccharide may be an oligosaccharide composition formed by the decomposition of a polysaccharide. Oligosaccharide compositions usually contain tetrasaccharides. Examples of the oligosaccharide composition include starch sugar (glycan starch), galactooligosaccharide, coupling sugar, fructooligosaccharide, xylo-oligosaccharide, soybean oligosaccharide, chitin oligosaccharide, chitosan oligosaccharide, and the like.

  For example, the starch sugar is an oligosaccharide composition obtained by allowing an acid or glucoamylase to act on starch, and may be a mixture of oligosaccharides in which a plurality of glucoses are bound. Examples of starch sugars include reduced starch saccharified products (trade name: PO-10, tetrasaccharide content of 90% by weight or more) manufactured by Towa Kasei Co., Ltd.

Galactooligosaccharide is an oligosaccharide composition obtained by reacting lactose with β-galactosidase or the like, and may be a mixture of galactosyl lactose and galactose- (glucose) _n (n is 1 to 4).

Coupling sugar is an oligosaccharide composition obtained by allowing a starch and sucrose to act on cyclodextrin synthase (CGTase), and may be a mixture of (glucose) _n -sucrose (n is 1 to 4).

Fructooligosaccharide (fructooligosaccharide) is an oligosaccharide composition obtained by allowing fructofuranosidase to act on sugar, and may be a mixture of sucrose- (fructose) _n (n is 1 to 4).

  In these oligosaccharide compositions, the content of trisaccharides and tetrasaccharides (particularly tetrasaccharides) in the oligosaccharide composition is, for example, 60% by weight or more (60% by weight) in order to prevent a sharp decrease in viscosity during melt kneading. To 100% by weight), preferably 70% by weight or more (70 to 100% by weight), more preferably 80% by weight or more (80 to 100% by weight), particularly 90% by weight or more (90 to 100% by weight).

  The oligosaccharide may be a reduced type (maltose type) or a non-reduced type (trehalose type), but a reduced type oligosaccharide is preferable because of its excellent heat resistance.

  The reduced oligosaccharide is not particularly limited as long as it has a free aldehyde group or ketone group and is a reducing sugar, and examples thereof include, for example, cozy biose, nigerose, maltose, isomaltose, sophorose, laminaribiote. Disaccharides such as sugar, cellobiose, gentiobiose, lactose, palatinose, melibiose, rutinose, primeverose, and turanose; trisaccharides such as maltotriose, isomalttriose, panose, cellotriose, manninotriose, and solatriose; Tetrasaccharides such as isomaltotetraose, cellotetraose and liquinose; pentasaccharides such as maltopentaose and isomaltopentaose; and hexasaccharides such as maltohexaose and isomaltohexaose.

  In general, since the oligosaccharide is a derivative of a polysaccharide that is a natural product or a product derived from a natural product produced by reduction thereof, the load on the environment can be reduced.

  In order to effectively disperse the resin component and the auxiliary component by kneading, it is desirable that the viscosity of the oligosaccharide is high. Specifically, when measured at a temperature of 25 ° C. using a B-type viscometer, the viscosity of the 50% by weight aqueous solution of the oligosaccharide is 1 Pa · s or more (for example, about 1 to 500 Pa · s), preferably 2 Pa · s. s or more (for example, about 2 to 250 Pa · s, particularly about 3 to 100 Pa · s), more preferably 4 Pa · s or more (for example, about 4 to 50 Pa · s), and especially 6 Pa · s or more (for example, 6 to 50 Pa · s). s), and it is desirable to use a high-viscosity oligosaccharide.

The melting point or softening point of the oligosaccharide (B ₁ ) is preferably higher than the heat distortion temperature of the resin component (A) (for example, the Vicat softening point specified in JIS K7206). In addition, depending on the kind of oligosaccharide (for example, starch sugar such as reduced starch saccharified product), the oligosaccharide does not show a melting point or a softening point and may be thermally decomposed. In such a case, the decomposition temperature may be the “melting point or softening point” of the oligosaccharide (B ₁ ).

The temperature difference between the melting point or softening point of the oligosaccharide (B ₁ ) and the heat deformation temperature of the resin component (A) is, for example, 1 ° C. or more (eg, about 1 to 80 ° C.), preferably 10 ° C. or more (eg, , About 10 to 70 ° C), more preferably 15 ° C or more (eg, about 15 to 60 ° C). The melting point or softening point of the oligosaccharide (B ₁ ) can be selected in the range of 70 to 300 ° C. depending on the type of the resin component (A), and is, for example, 90 to 290 ° C., preferably 100 to 280 ° C. (for example, , 110-270 ° C), more preferably about 120-260 ° C (eg, 130-260 ° C). In general, an anhydride of an oligosaccharide shows a high melting point or softening point. For example, in the case of trehalose, the melting point of dihydrate is 97 ° C, while the melting point of anhydride is 203 ° C. When the melting point or softening point of the oligosaccharide is higher than the heat deformation temperature of the resin component (A), not only can the sudden decrease in viscosity of the oligosaccharide during melt kneading be prevented, but also thermal degradation of the oligosaccharide can be suppressed.

Further, in the present invention, in the water-soluble auxiliary component (B), the oligosaccharide (B ₁ ) is combined with a water-soluble plasticizing component (B ₂ ) for plasticizing the oligosaccharide (B ₁ ). In kneading with the resin component (A), the viscosity of the water-soluble auxiliary component (B) can be adjusted.

(2) Plasticizing component (B ₂ )
The plasticizing component (B ₂ ) is not particularly limited as long as it can exhibit the phenomenon that the oligosaccharide (B ₁ ) hydrates and becomes a syrup, and examples thereof include saccharides and sugar alcohols. These plasticizing components can be used alone or in combination of two or more.

(a) Saccharides Monosaccharides and / or disaccharides are usually used as saccharides in order to effectively plasticize oligosaccharides (B ₁ ). These saccharides can be used alone or in combination of two or more.

Examples of the monosaccharide include triose, tetrose, pentose, hexose, heptose, octose, nonose, and decose. These compounds may be aldose or ketose, and may be dialdose (a compound that is a sugar derivative and has both ends of the carbon chain being aldehyde groups, for example, tetraacetylgalactohexodialdose, idhexodialdose, xylopentose). Aldose), monosaccharides having a plurality of carbonyl groups (such as aldoalkoketoses such as oson and onose), monosaccharides having a methyl group (methyl sugars such as altromethylose), and acyl groups (particularly C ₂ such as acetyl groups). Monosaccharides having an _-4 acyl group (eg, the acetylated form of the aldose, for example, an acetylated form such as an aldehyde glucose pentaacetyl compound), a saccharide having a carboxyl group introduced therein (sugar acid or uronic acid), a thiosugar, an amino sugar And deoxy sugars.

  Specific examples of such monosaccharides include, for example, tetroses (erythrose, threolose, etc.), pentoses (arabinose, ribose, lyxose, deoxyribose, xylose, etc.), hexoses (allose, altrose, glucose, mannose, gulose, idose). , Galactose, fructose, sorbose, fucose, rhamnose, talose, galacturonic acid, glucuronic acid, mannuronic acid, glucosamine, etc.).

  Further, the monosaccharide may be a cyclic isomer having a cyclic structure formed by a hemiacetal bond. The monosaccharide does not need to have optical rotation, but may be any of D-form, L-form, and DL-form. These monosaccharides can be used alone or in combination of two or more.

The disaccharide is not particularly limited as long as it can plasticize the oligosaccharide (B ₁ ). For example, among the disaccharides, disaccharides having a low melting point or a low softening point (for example, gentibiose, melibiose, Trehalose (dihydrate), and disaccharides corresponding to homo- and hetero-disaccharides of the above-mentioned monosaccharides (for example, aldobiouronic acid such as glucuronoglucose in which glucuronic acid and glucose are α-1,6 glycoside-linked). Can be illustrated.

  Since saccharides are excellent in thermal stability, reducing sugars are preferable. Such saccharides include free monosaccharides and, among the disaccharides, reducing sugars having a low melting point or a low softening point (eg, gentibiose, melibiose). Etc.).

(b) Sugar alcohol The sugar alcohol may be a chain sugar alcohol such as alditol (glycitol) or a cyclic sugar alcohol such as inosit, but usually, a chain sugar alcohol is used. You. These sugar alcohols can be used alone or in combination of two or more.

  Examples of chain sugar alcohols include tetritol (threitol, erythritol, etc.), pentitol [pentaerythritol, arabitol, ribitol (adonitol), xylitol, lyxitol, etc.], hexitol [sorbitol, mannitol, iditol, glitol, thallitol, dulcitol (ga Lactitol), allozurcitol (allitol), arsuritol], heptitol, octitol, nonitol, dexitol, dodecitol, and the like.

  Of these sugar alcohols, erythritol, pentaerythritol, arabitol, ribitol, xylitol, sorbitol, dulcitol and mannitol are preferred. The sugar alcohol often includes at least one sugar alcohol selected from erythritol, pentaerythritol, and xylitol.

The plasticizing component (B ₂ ) may be liquid (syrup-like) at normal temperature (for example, about 15 to 20 ° C.), but is usually solid in many cases from the viewpoint of handleability and the like. When the auxiliary component (B) is composed of the oligosaccharide (B ₁ ) and the plasticizing component (B ₂ ), the oligosaccharide (B ₁ ) is a thermally decomposable oligosaccharide having no distinct melting point or softening point. Can also be effectively plasticized or softened.

The melting point or softening point of the plasticizing component (B ₂ ) is usually equal to or lower than the heat distortion temperature of the resin component (A) (for example, the Vicat softening point specified in JIS K7206). Note that, among the plasticizing components, there is a substance that has a high melting point (for example, 200 ° C. or higher) but melts at a temperature lower than the actual melting point when coexisting with an oligosaccharide. For example, pentaerythritol exerts a plasticizing effect on oligosaccharides at a temperature lower than the actual melting point (260 ° C.) (for example, about 160 to 180 ° C.), and itself becomes a molten state. Such a plasticizing component having a high melting point cannot be used alone because it does not melt at the heat deformation temperature of the resin component, but can be effectively used by combining it with an oligosaccharide. In the case of a plasticizing component (for example, pentaerythritol) that exerts a plasticizing effect on oligosaccharides at a temperature lower than the actual melting point, the temperature at which the plasticizing effect on oligosaccharides is determined by the plasticizing component (B ₂ ) May be used as the “melting point or softening point”.

  The melting point or softening point of the auxiliary component (B) may be higher or lower than the heat deformation temperature of the resin component (A). The resin component (A) and the auxiliary component (B) may be melted or softened at least at a kneading temperature (or a molding temperature). For example, the temperature difference between the melting point or softening point of the auxiliary component (B) and the heat deformation temperature of the resin component (A) may be selected in the range of 0 to 100 ° C, for example, 3 to 80 ° C ( For example, the temperature may be about 3 to 55 ° C), preferably about 5 to 60 ° C (for example, 5 to 45 ° C), and more preferably about 5 to 40 ° C (for example, 10 to 35 ° C). When the temperature difference between the melting point or softening point of the auxiliary component (B) and the heat deformation temperature of the resin component (A) is small (for example, when the temperature difference is about 0 to 20 ° C.), There is an advantage that the dispersion form can be fixed in a short time by a high auxiliary component (B) (for example, a sugar component).

Further, the melt flow rate of the auxiliary component (B) composed of the oligosaccharide (B ₁ ) and the plasticizing component (B ₂ ) is determined by, for example, the heat distortion temperature of the resin component (A) (for example, the Vicat softening). When the melt flow rate specified by JIS K 7210 is measured at a temperature 30 ° C. higher than (point), 1 or more (for example, about 1 to 40), preferably 5 or more (for example, about 5 to 30), more preferably It may be 10 or more (for example, about 10 to 20).

In the auxiliary component (B), the ratio (weight ratio) of the plasticizing component (B ₂ ) is such that the plasticizing component does not localize due to aggregation or the like during the melt-kneading, and the oligosaccharide (B ₁ ) is efficiently used. Plasticizable amount, for example, oligosaccharide (B ₁ ) / plasticizing component (B ₂ ) = 99/1 to 50/50, preferably 95/5 to 60/40, more preferably 90/50. It is about 10-70 / 30.

  The ratio (weight ratio) between the resin component (A) and the auxiliary component (B) can be selected according to the type and viscosity of the resin component and the auxiliary component, the compatibility between the resin component and the auxiliary component, and the like. Although not limited, usually, an amount that does not impair moldability, for example, resin component (A) / auxiliary agent component (B) = 55/45/1/99, preferably 50/50 to 5/95, and more preferably 45/45. / 55 to 10/90.

(Other additives)
The biodegradable resin component (A) and / or the water-soluble auxiliary component (B) may optionally contain various additives such as a filler, a plasticizer or a softener, and a photodegradability-imparting agent (anatase type). Contains titanium oxide, lubricant, stabilizer (heat stabilizer, antioxidant, ultraviolet absorber), thickener, coloring agent (titanium oxide, carbon black, etc.), dispersant, flame retardant, antistatic agent, etc. May be.

  In the present invention, a dispersion in which the biodegradable resin is dispersed in the form of particles is prepared using the components (the biodegradable resin component and the auxiliary component). Although the method for preparing the dispersion is not particularly limited, usually, the biodegradable resin component (A) and the water-soluble auxiliary component (B) are kneaded.

  The kneading of the biodegradable resin component (A) and the water-soluble auxiliary component (B) can be performed using a conventional kneader (for example, a single-screw or twin-screw extruder, a kneader, a calender roll, etc.). it can. Prior to kneading, the resin component and the auxiliary component may be preliminarily kneaded in a powder form by a freeze grinder or the like, or may be preliminarily kneaded by a Henschel mixer, a tumble mixer, a ball mill, or the like.

[Auxiliary component elution step]
The water-soluble auxiliary component may be eluted from the kneaded product. However, usually, after kneading, molding is performed to elute the water-soluble auxiliary component. Examples of the molding method include extrusion molding, injection molding, blow molding, and calendar molding. Extrusion molding or injection molding is usually used in terms of productivity and ease of processing. The shape of the preform (or dispersion) is not particularly limited, and may be a zero-dimensional shape (granular, pellet-like, etc.), a one-dimensional shape (strand-like, rod-like, etc.), or a two-dimensional shape (plate-like, sheet-like). Shape, film shape, etc.), and three-dimensional shape (tubular, block shape, etc.). In consideration of the dissolution property of the auxiliary component, it is preferable to process into a strand, a rod, a sheet, or a film.

  The particle shape and particle size are determined by the compatibility between the resin component and the auxiliary component, the melt viscosity of the resin component and the auxiliary component, kneading conditions (for example, kneading time, kneading temperature, etc.), molding processing temperature, and cooling conditions (for example, , Cooling time, cooling temperature, etc.).

  The compatibility between the resin component (A) and the auxiliary component (B) is not particularly limited, and may be incompatible or compatible. When the resin component and the auxiliary component are compatible, even if the resin component and the auxiliary component form a uniform single phase at the kneading temperature, the standing time after kneading, the surface tension of both during the cooling process, Due to a difference in solidification rate such as crystallization, the resin component and the auxiliary component can be phase-separated, and a dispersion system can be formed between the resin component and the auxiliary component. Even in a system in which the resin component and the auxiliary component are compatible, the reason that the resin component and the auxiliary component can be phase-separated is that the auxiliary component has a low surface tension and at a kneading temperature with the resin component. Has a unique physical property that it can maintain a relatively high viscosity and has a low molecular weight, so that the solidification rate during cooling is faster than that of the resin component.

  The kneading time can be selected, for example, from the range of 10 seconds to 1 hour, and is usually about 30 seconds to 45 minutes, preferably about 1 to 30 minutes (for example, about 1 to 10 minutes). The kneading temperature and the molding temperature can be appropriately set according to the raw materials used (for example, a resin component and an auxiliary component), and are, for example, 90 to 300 ° C, preferably 110 to 260 ° C, and more preferably. Is about 140 to 240 ° C (for example, 170 to 240 ° C), particularly about 170 to 230 ° C (for example, 180 to 220 ° C). In order to avoid the thermal decomposition of the auxiliary components (oligosaccharide and plasticizing component), the kneading temperature and the molding temperature may be set to 230 ° C. or lower.

  The dispersion system (a form in which the biodegradable resin component and the auxiliary component are dispersed) is formed by kneading and / or molding and then cooling the melt (for example, a kneaded product or a preform) as appropriate. Is also good. For example, the cooling temperature may be a temperature that is at least about 10 ° C. lower than the heat deformation temperature of the resin component or the melting point or softening point of the auxiliary component. (Melting point or softening point of the component) about 10 to 100 ° C., preferably about 15 to 80 ° C. below the above temperature, more preferably about 20 to 60 ° C. below the above temperature. Specifically, for example, the cooling temperature can be selected from the range of 5 to 150 ° C. depending on the type of the resin component or the auxiliary component, and is, for example, 10 to 120 ° C. (eg, 10 to 60 ° C.), preferably 15 to 150 ° C. -100 ° C (for example, 15-50 ° C), and more preferably about 20-80 ° C (for example, 20-40 ° C). The cooling time can be appropriately set according to the type of the resin component and the auxiliary component, the cooling temperature, and the like, and may be selected from a wide range of 30 seconds to 20 hours, for example, 45 seconds to 10 hours, preferably It may be 1 minute to 5 hours (for example, 1 minute to 1 hour), more preferably about 1.5 to 30 minutes. By cooling, even if the resin component and the auxiliary component are compatible, in the cooling step, a dispersion system can be formed due to a difference in solidification rate such as surface tension and crystallization, and a dispersion can be obtained.

  In the dispersion obtained as described above, since the auxiliary component (B) forms a continuous phase in the sea-island structure (a phase-separated structure in which the resin phase is independent), the auxiliary component can be rapidly eluted. .

The auxiliary component is eluted or washed by dispersing in a solvent [water, a water-soluble solvent (eg, alcohols (methanol, ethanol, propanol, isopropanol, butanol, etc.), ethers (cellosolve, butyl cellosolve, etc.), etc.)). The resin particles can be obtained by dissolving the auxiliary component from the dispersion. As the solvent, water is preferable because the load on the environment is small and the industrial cost can be reduced. The auxiliary component can be eluted using a conventional method, for example, under normal pressure (for example, about 10 × 10 ⁴ Pa), under reduced pressure, or under increased pressure. The dissolution temperature of the auxiliary component can be appropriately set according to the resin component and the auxiliary component. For example, a temperature lower than the melting point or softening point of the resin component, for example, 10 to 100 ° C, preferably 25 to 90 ° C, More preferably, it is about 30 to 80 ° C (for example, 40 to 80 ° C). Since the water-soluble auxiliary component is easily soluble in water, it does not require a large amount of water.

  The resin particles can be recovered using a recovery method such as filtration or centrifugation. In the obtained resin particles, it is desirable that the auxiliary component does not remain. For example, even if the auxiliary component remains in the resin particles in a small amount, the auxiliary Since the component is a compound derived from a natural product, there is little adverse effect on the resin particles.

  The auxiliary component extracted with the solvent can be easily recovered by using a conventional separation means (for example, distillation, concentration, recrystallization, etc.).

[Biodegradable resin particles]
The shape of the biodegradable resin particles obtained by the above method is not particularly limited as long as it is in the form of particles, for example, spherical, elliptical, polygonal, prismatic, cylindrical, rod-like, indefinite and the like. There may be. According to the production method of the present invention, spherical, especially spherical biodegradable resin particles can be easily produced. The spherical shape is not limited to a true sphere, and includes, for example, a shape in which the ratio of the major axis to the minor axis is about major axis / minor axis = 1.5 / 1 to 1/1, and preferably 1.3 / 1. To 1/1, more preferably about 1.1 / 1 to 1/1.

  The average particle size of the biodegradable resin particles is not particularly limited, and can be selected from a range of about 0.1 μm to 1 mm depending on the use. For example, 0.1 to 800 μm (for example, 0.1 to 500 μm), or preferably It is about 0.1 to 100 μm (for example, 0.5 to 80 μm), and more preferably about 0.5 to 50 μm (for example, 1 to 40 μm). The coefficient of variation of the particle diameter ([standard deviation of particle diameter / average particle diameter] × 100) is 60 or less (for example, about 5 to 60), and more preferably 50 or less (for example, about 10 to 50).

  The number average molecular weight (in terms of polystyrene) of the biodegradable resin constituting the biodegradable resin particles can be selected, for example, in the range of 250,000 or less (for example, about 2,000 to 250,000), and preferably 5, It is about 000 to 200,000, more preferably about 10,000 to 150,000. For a biodegradable resin, such as a cellulose derivative, whose molecular weight is difficult to measure by gel permeation chromatography, a viscosity average degree of polymerization corresponding to the number average molecular weight can be employed. The number average molecular weight can be adjusted by the kneading time and kneading temperature of the biodegradable resin component (A).

  In the method for producing biodegradable resin particles of the present invention, the content of the water-soluble auxiliary component in the prepared biodegradable resin particles is included because the water-soluble auxiliary component having high elution property is used. Even a very small amount (for example, 3% by weight or less, preferably 1% by weight or less, more preferably 0.5% by weight or less based on the whole particles). In particular, the biodegradable resin particles do not substantially contain a water-soluble auxiliary component, and the content of the water-soluble auxiliary component is, for example, 0.1% by weight or less based on the whole particles, preferably Is 0.05% by weight or less, more preferably 0.01% by weight or less, and is often a concentration below the detection limit. Furthermore, since most of the water-soluble auxiliary components are foods or food additives, even if they are contained in the biodegradable resin particles, the safety is high.

  Since the biodegradable resin particles of the present invention are excellent in biodegradability, they are used for agricultural chemicals, pharmaceuticals, cosmetics, paints (eg, powder paints, ship bottom paints, etc.), coating agents, adhesives, inks, toners, and antiblocking agents. It is useful as a raw material or an additive in the field of fine chemicals such as a spacer and a spacer. Additives for agriculture, forestry and fisheries, civil engineering and construction films and sheets, sanitary goods such as disposable diapers, medical materials requiring biodegradability and absorbability, and sustained release requiring sustained release It is also useful as a conductive material.

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

Examples 1 to 5 and Comparative Examples 1 and 2
A resin composition composed of a biodegradable resin component having a composition shown in Table 1 and a water-soluble auxiliary component was melted at a set temperature of 200 ° C. for 5 minutes by Brabender (Labo Plastmill, manufactured by Toyo Seiki Co., Ltd.). After kneading, the mixture was allowed to stand at 30 ° C. for 10 minutes, and then a plate-like dispersion having a thickness of 1 mm was prepared using a press machine at 200 ° C. and 200 kg / cm ² (about 20 MPa) for 3 minutes. The obtained dispersion was immediately cooled at 30 ° C. for 3 minutes, and then immersed in hot water at 60 ° C. to obtain a suspension of resin particles. Using a membrane membrane made of polyvinylidene fluoride having a pore size of 0.45 μm, resin particles were recovered by separating insoluble components from this suspension solution. In addition, each component used, the compatibility, and the evaluation method of the obtained fine particles are as follows. Table 1 shows the results.

(Resin component)
Resin-1: Cellulose acetate butyrate resin (manufactured by Eastman Co., Ltd., CAB171-15S)
Resin-2: polylactic acid (Laicia H-100PL, manufactured by Mitsui Chemicals, Inc.)
Resin-3: polycaprolactone-polybutylene succinate copolymer resin (manufactured by Daicel Chemical Industries, Ltd., caprolactone content 10 mol%, MFR (190 ° C./2160 g) 1 g / 10 min)
Resin-4: ethylene-vinyl alcohol copolymer resin (Kuraray Co., Ltd., EP-L101B, ethylene content 19.8% by weight)
Resin-5: polystyrene resin (Toyo Styrene Co., Ltd., GPPS HRM63C)
Resin-6: Nylon 12 resin (Daicel L1600, manufactured by Daicel Degussa Co., Ltd.)
(Auxiliary component)
Auxiliary component-1 (oligosaccharide): starch sugar (manufactured by Towa Kasei Co., Ltd., reduced starch saccharified product PO-10, viscosity of a 50% by weight aqueous solution measured at 25 ° C. with a B-type viscometer: 6.5 Pa · s) )
Auxiliary component-2 (a) (plasticizing component): sugar alcohol (pentaerythritol, manufactured by Wako Pure Chemical Industries, Ltd.)
Auxiliary component-2 (b) (plasticizing component): sugar alcohol (D (-) sorbitol, manufactured by Wako Pure Chemical Industries, Ltd.).

(Evaluation of compatibility between resin component and auxiliary component)
A thermal analysis method by differential scanning calorimetry (DSC) was used to determine whether the resin component and the auxiliary component were in a compatible state at the kneading temperature. The method is described in detail below.

  As a measuring apparatus, a differential scanning calorimeter (DSC: DSC600E, manufactured by Shimadzu Corporation) was used. The resin component and the auxiliary component having the compounding ratio shown in Table 1 were previously kneaded for 5 minutes at a kneading temperature (200 ° C.) using a Brabender (Labo Plastmill, manufactured by Toyo Seiki Co., Ltd.) to obtain a sample. . This sample is supplied to a measuring apparatus, and once heated to 200 ° C. and left for 5 minutes. Then, according to JIS K7121, at a temperature decreasing rate of 10 ° C./min, the exothermic peak accompanying the crystallization of the resin component is taken from the peak top position. The crystallization temperature was measured by reading the temperature. The crystallization temperature of the resin component alone was measured by performing the same operation on the resin component.

  For the crystalline resin component, the crystallization temperature of the resin component alone is compared with the crystallization temperature of the resin component measured using a mixture of the resin component and the auxiliary component. When it was within, it was determined that there was compatibility between the resin component and the auxiliary component.

  Since the crystallization temperature of an amorphous resin cannot be measured, the crystallization temperature of the oligosaccharide measured in the above procedure for the auxiliary component and the crystal of the oligosaccharide measured for the mixture of the resin component and the auxiliary component are used. When the temperature difference between the two was within 1 ° C., it was determined that there was compatibility between the resin component and the auxiliary component.

(Average particle size of resin particles)
After drying the collected resin fine particles, the shape of the fine particles was observed using a scanning electron microscope. A suspension is prepared by dispersing an appropriate amount of the dried resin fine particles again in pure water, and the number average particle size is measured using a laser diffraction type particle size distribution meter (SALD-2000J, manufactured by Shimadzu Corporation). The diameter was measured. Further, a coefficient of variation was calculated for 100 randomly extracted resin fine particles.

(Environmental)
The impact on the environment was evaluated according to the following criteria.

実施例１〜５では、樹脂成分と助剤成分とが、相溶系又は非相溶系のいずれにおいても、真球状の球状樹脂微粒子を得ることができた。参考のため、実施例１で得られたセルロースアセテートブチレート樹脂の球状微粒子の電子顕微鏡写真を図１に示す。 A: The auxiliary component is composed of only a natural product-derived compound. B: The auxiliary component is composed of a natural product-derived compound and a low molecular weight industrial product.

In Examples 1 to 5, true spherical spherical resin fine particles could be obtained regardless of whether the resin component and the auxiliary component were compatible or incompatible. For reference, an electron micrograph of the spherical fine particles of the cellulose acetate butyrate resin obtained in Example 1 is shown in FIG.

  Further, in Comparative Example 1 in which pentaerythritol, which is a sugar alcohol that is not completely plasticized at the heat deformation temperature of the resin component, was used as the auxiliary component, the dispersion obtained by melt-kneading was immersed in water to form the auxiliary component. Even after the removal, the resin component did not become fine particles, and a sponge-like lump having pores having a pore diameter of more than 100 μm was obtained.

  Further, in Comparative Example 2 in which sorbitol, which is a sugar alcohol having a melting point lower than the heat distortion temperature of the resin component, was used as the auxiliary component, kneading with the resin component was performed because the viscosity of the auxiliary component was too low during melt kneading. I couldn't do that.

FIG. 1 is a scanning electron micrograph of the particles obtained in Example 1.

Claims (23)

A biodegradable resin component (A) and a water-soluble auxiliary component (B) containing at least an oligosaccharide (B ₁ ), and a dispersion in which the biodegradable resin component (A) is dispersed in the form of particles, A method for producing biodegradable resin particles by eluting a water-soluble auxiliary component (B).   The method according to claim 1, wherein spherical biodegradable resin particles are produced.   The method according to claim 1, wherein the biodegradable resin component (A) is composed of at least one selected from a polyester resin, a polyether resin, a vinyl alcohol resin, and a cellulose derivative.   The method according to claim 1, wherein the biodegradable resin component (A) comprises at least an aliphatic polyester resin. A unit (a) in which the biodegradable resin component (A) is represented by the following formula:
—OC—R ¹ —CO— (a)
(Wherein, R ¹ represents a direct bond or a divalent aliphatic hydrocarbon group which may have a substituent)
And a unit (b) represented by the following formula:
—OR ² —O— (b)
(Wherein, R ² represents a divalent aliphatic hydrocarbon group which may have a substituent)
An aliphatic polyester resin (A ₁ ) composed of
Unit (c) represented by the following formula
—OR ³ —CO— (c)
(Wherein, R ³ represents a divalent aliphatic hydrocarbon group which may have a substituent)
Configuration in configuration aliphatic polyester resin (A _2), and at least one member selected from the unit (a) and (b) and (c) a de-configured aliphatic polyester resin (A ₃₎ The method of claim 1, wherein the method is performed.   The method according to claim 1, wherein the biodegradable resin component (A) comprises an aliphatic polyester resin and an aromatic polyester resin. The method according to claim 1, wherein the oligosaccharide (B ₁ ) exhibits a melting point or softening point or decomposes at a temperature higher than the heat deformation temperature of the resin component (A). The method according to claim 1, wherein the oligosaccharide (B ₁ ) comprises at least a tetrasaccharide. The method of claim 1, wherein the oligosaccharide (B ₁₎ is contained in an amount of more than 60 wt% tetrasaccharides. The method according to claim 1, wherein the viscosity of the 50% by weight aqueous solution of the oligosaccharide (B ₁ ) is 1 Pa · s or more when measured with a B-type viscometer at a temperature of 25 ° C. Auxiliary component (B) is The method of claim 1, further oligosaccharides (B ₁₎ containing a water-soluble plasticizing component (B ₂₎ to plasticize. Melting or softening point of the plasticizing component (B ₂₎ The method of claim 11, wherein the heat distortion temperature or less of the resin component (A). Plasticizing component (B ₂₎ is, sugars and method according to claim 11, characterized in that composed of at least one selected from sugar alcohols.   14. The method according to claim 13, wherein the sugar alcohol comprises at least one selected from erythritol, pentaerythritol, arabitol, ribitol, xylitol, sorbitol, dulcitol, and mannitol. The biodegradable resin component (A) has a Vicat softening point of 60 to 300 ° C. as defined by JIS K 7206 and, when measured with a B-type viscometer at a temperature of 25 ° C., 50 weight of the oligosaccharide (B ₁ ) % Aqueous solution has a viscosity of 3 to 100 Pa · s, and when the melt flow rate specified by JIS K 7210 is measured at a temperature 30 ° C. higher than the Vicat softening point, the oligosaccharide (B ₁ ) and the plasticizing component (B 12. The method according to claim 11, wherein the melt flow rate of the auxiliary component (B) composed of ₂ ) and 1) is 1 or more.   The ratio (weight ratio) of the biodegradable resin component (A) and the auxiliary component (B) is 55/45/1/99 as the ratio of the resin component (A) / the auxiliary component (B). the method of. The ratio (weight ratio) of the oligosaccharide (B ₁ ) and the plasticizing component (B ₂ ) is oligosaccharide (B ₁ ) / plasticizing component (B ₂ ) = 99/1 to 50/50. The described method. A biodegradable resin component (A) and a water-soluble auxiliary component (B) containing an oligosaccharide (B ₁ ) and a water-soluble plasticizing component (B ₂ ) for plasticizing the oligosaccharide (B ₁ ). A method for producing spherical biodegradable resin particles by eluting a water-soluble auxiliary component (B) from a dispersion composition, wherein the biodegradable resin component (A) is a cellulose derivative or an aliphatic polyester. (B ₁ ), which is composed of at least one selected from the group consisting of a series resin and a vinyl alcohol-based resin, and constitutes the auxiliary component (B), comprises starch sugar, galactooligosaccharide, coupling sugar, fructooligosaccharide, xylo-oligosaccharide , soybean oligosaccharides, composed of at least one member selected from chitin oligosaccharide and chitosan oligosaccharide, the plasticizing component (B ₂₎ is, erythritol, pentaerythritol, xylitol, and Seo It is composed of at least one selected from bitol, and the ratio (weight ratio) between the resin component (A) and the auxiliary component (B) is 50 / 50-5 (resin component (A) / auxiliary component (B)). / 95, the proportion of oligosaccharide and (B ₁₎ and the plasticizing component (B ₂₎ (weight ratio), oligosaccharide (B ₁₎ / plasticizing component _{(B 2) = 95 / 5~60} / 40 A method for producing biodegradable resin particles.   Biodegradable resin particles obtained by the production method according to claim 1.   The biodegradable resin particles according to claim 19, wherein the biodegradable resin particles are spherical particles having an average particle diameter of 0.1 to 100 µm and a coefficient of variation of the average particle diameter of 60 or less.   The biodegradable resin particles according to claim 19, wherein the ratio of the major axis to the minor axis of the biodegradable resin particles is major axis / minor axis = 1.1 / 1 to 1/1.   The biodegradable resin particles according to claim 19, wherein the number average molecular weight of the biodegradable resin particles is 250,000 or less.   20. The biodegradable resin particle according to claim 19, comprising 3% by weight or less of a water-soluble auxiliary component (B) based on the whole particle.

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