JP5369673B2 - Aliphatic polyester resin composition and molded article formed by molding the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aliphatic polyester resin composition which has excellent moldability and mechanical strength, and for which deposition of oligomers originating from the aliphatic polyester resin on the surface is suppressed, and to provide a molded body thereof. <P>SOLUTION: The aliphatic polyester resin composition contains at least the aliphatic polyester resin, starch and an organic compound containing hydroxyl group. The organic composition containing the hydroxyl group of 3 mass parts to 40 mass parts is blended into the aliphatic polyester resin of 100 mass parts, and the content of cyclic dimers incorporated in the aliphatic polyester resin is within the range of 1,000-10,000 ppm. The molded body is obtained by molding the composition. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to an aliphatic polyester resin composition having good moldability, mechanical strength, and the like, and further, an aliphatic polyester resin composition in which precipitation on the surface of an oligomer derived from the aliphatic polyester resin is suppressed. The present invention relates to a product and a molded body thereof.

  Conventionally, paper, plastic film, aluminum foil, and the like have been used in a wide range of applications such as liquids and granules for various foods, medicines, miscellaneous goods, solid packaging materials, agricultural materials, and building materials. In particular, plastic films are excellent in strength, water resistance, moldability, transparency, cost, etc., and are used in many applications as bags and containers.

  For example, aliphatic polyester resins are applied to various molded products such as films, but if molded products using aliphatic polyester resins are left to stand for a while, oligomers, especially cyclic dimers, are deposited on the surface, and the surface is There was a problem of whitening. As a technique for reducing oligomers contained in aliphatic polyester resins, especially cyclic dimers, aliphatic polyesters may be aliphatic with one or more solvents selected from aliphatic ketones, cyclic aliphatic ethers, and aliphatic monoesters. A technique of washing at a temperature lower than the melting point of the polyester and lower than the boiling point of the solvent is disclosed (Patent Document 1). However, this method has a problem that the manufacturing process becomes complicated and the used organic solvent remains in the resin.

  The aliphatic polyester resin has good moldability, but has insufficient mechanical properties such as tear strength and tensile elongation at break of the film (Patent Document 2). As an attempt to improve the mechanical properties of the aliphatic polyester resin, preparation of a composition of starch and aliphatic polyester has also been carried out, but the problem of whitening of the molded product by the oligomer derived from the above aliphatic polyester resin Was still not resolved.

Further, although a resin composition composed of a thermoplastic resin and a starchy material composed mainly of an amylopectin material has been disclosed (Patent Document 3), the improvement of the mechanical properties has been insufficient.
JP 2002-003606 A JP-A-8-239461 Japanese Patent Laid-Open No. 6-041351

  The present invention has been made in view of the above-mentioned background art, and the problem is that the aliphatic polyester has good moldability and mechanical strength and suppresses precipitation of oligomers derived from the aliphatic polyester resin on the surface. It is providing the resin composition and its molded object.

  As a result of intensive studies to solve the above problems, the present inventors have melt-kneaded an aliphatic polyester resin, starch, and an organic compound containing a hydroxyl group so that the starch is plasticized by the organic compound containing a hydroxyl group. As a result, the resulting aliphatic polyester resin composition has good moldability and mechanical strength, and the oligomer derived from the aliphatic polyester resin dissolves in an organic compound containing a hydroxyl group. Then, it was found that oligomer precipitation on the surface of the molded body could be suppressed, and the present invention was completed.

  That is, the present invention is a resin composition containing at least an aliphatic polyester resin, starch and an organic compound containing a hydroxyl group, wherein the compounding amount of the organic compound containing a hydroxyl group is 100 parts by mass of the aliphatic polyester resin. On the other hand, the aliphatic polyester resin composition is characterized in that it is 3 parts by weight or more and 40 parts by weight or less, and the content of the cyclic dimer contained in the aliphatic polyester resin is in the range of 1000 to 10,000 ppm. Is.

  Moreover, this invention provides the molded object formed by shape | molding the said aliphatic polyester resin composition.

  ADVANTAGE OF THE INVENTION According to this invention, it can provide the aliphatic polyester resin composition which has favorable moldability and mechanical strength, and the precipitation to the surface of the oligomer derived from an aliphatic polyester resin was suppressed, and its molded object. .

  Hereinafter, the present invention will be described. However, the present invention is not limited to the specific embodiments described below, and includes modifications that are arbitrarily modified within the technical scope of the present invention.

<Aliphatic polyester resin>
In the present invention, the aliphatic polyester resin refers to a polyester resin having substantially no aromatic ring in the molecule. The aliphatic polyester resin in the present invention preferably contains a diol unit and a dicarboxylic acid unit, and more preferably, for example, a chain aliphatic and / or alicyclic diol unit represented by the following formula (1), and These are composed of chain aliphatic and / or alicyclic dicarboxylic acid units represented by the following formula (2).
—O—R ¹ —O— (1)
[In the formula (1), R ¹ represents a divalent chain aliphatic hydrocarbon group and / or a divalent alicyclic hydrocarbon group. When copolymerized, two or more types of R ¹ may be contained in the resin. ]
^-OC-R 2 -CO- (2)
[In the formula (2), R ² represents a divalent chain aliphatic hydrocarbon group and / or a divalent alicyclic hydrocarbon group. When copolymerized, two or more types of R ¹ may be contained in the resin. ]

  In the formulas (1) and (2), “and” in the “divalent chain aliphatic hydrocarbon group and / or divalent alicyclic hydrocarbon group” means in one molecule of the constituent component. This means that it may contain both a divalent chain aliphatic hydrocarbon group and a divalent alicyclic hydrocarbon group. Hereinafter, “chain aliphatic and / or alicyclic” may be simply abbreviated as “aliphatic”.

  Although the aliphatic diol component which gives the diol unit of Formula (1) is not particularly limited, an aliphatic diol component having 2 to 10 carbon atoms is preferable, and an aliphatic diol component having 4 to 6 carbon atoms is particularly preferable. Specifically, for example, 1,3-propanediol, 1,4-butanediol, 1,4-cyclohexanedimethanol and the like can be mentioned, among which 1,4-butanediol is particularly preferable. Two or more types of aliphatic diol components can be used.

  The aliphatic dicarboxylic acid component that gives the dicarboxylic acid unit of the formula (2) is not particularly limited, but an aliphatic dicarboxylic acid component having 2 to 10 carbon atoms is preferable, and an aliphatic dicarboxylic acid component having 4 to 8 carbon atoms is preferable. Particularly preferred. Specific examples of the aliphatic dicarboxylic acid component include succinic acid, adipic acid, suberic acid, sebacic acid, dodecanedioic acid and the like, and succinic acid or adipic acid is particularly preferable. Two or more types of aliphatic dicarboxylic acid components can be used.

  Furthermore, the aliphatic polyester resin in the present invention may contain an aliphatic oxycarboxylic acid unit. Specific examples of the aliphatic oxycarboxylic acid that gives an aliphatic oxycarboxylic acid unit include, for example, lactic acid, glycolic acid, 2-hydroxy-n-butyric acid, 2-hydroxycaproic acid, 6-hydroxycaproic acid, and 2-hydroxy3. , 3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, 2-hydroxyisocaproic acid and the like, or lower alkyl esters or intramolecular esters thereof. When optical isomers exist in these, any of D-form, L-form and racemic form may be sufficient, and a form may be a solid, a liquid, or aqueous solution. Of these, lactic acid or glycolic acid is particularly preferred. These aliphatic oxycarboxylic acids can be used alone or as a mixture of two or more.

  The amount of the aliphatic oxycarboxylic acid is, in all components constituting the aliphatic polyester resin, the lower limit is usually 0 mol% or more, preferably 0.01 mol% or more, and the upper limit is usually 30 mol% or less. Preferably it is 20 mol% or less.

  In addition, the aliphatic polyester resin in the present invention includes “a trifunctional or higher aliphatic polyhydric alcohol”, “a trifunctional or higher aliphatic polyvalent carboxylic acid or acid anhydride thereof”, or “a trifunctional or higher aliphatic polyvalent alcohol”. Copolymerization of “oxycarboxylic acid” is preferred because the melt viscosity of the resulting aliphatic polyester resin can be increased.

  Specific examples of the trifunctional aliphatic polyhydric alcohol include trimethylolpropane and glycerin, and specific examples of the tetrafunctional aliphatic polyhydric alcohol include pentaerythritol. These may be used alone or in combination of two or more.

  Specific examples of the trifunctional aliphatic polyvalent carboxylic acid or its acid anhydride include propanetricarboxylic acid or its acid anhydride, and specific examples of the tetrafunctional polyvalent carboxylic acid or its acid anhydride include: Examples include cyclopentanetetracarboxylic acid or acid anhydrides thereof. These may be used alone or in combination of two or more.

  In addition, the trifunctional aliphatic oxycarboxylic acid component includes (i) a type having two carboxyl groups and one hydroxyl group in the same molecule, and (ii) one carboxyl group and two hydroxyl groups. Any type can be used. Specifically, malic acid or the like is preferably used. In addition, the tetrafunctional aliphatic oxycarboxylic acid component includes (i) a type in which three carboxyl groups and one hydroxyl group are shared in the same molecule, and (ii) two carboxyl groups and two hydroxyl groups. It is divided into a type that shares a group in the same molecule, and (iii) a type that shares three hydroxyl groups and one carboxyl group in the same molecule, and any type can be used. Specific examples include citric acid and tartaric acid. These may be used alone or in combination of two or more.

  The amount of such a tri- or higher functional compound is generally 0 mol% or more, preferably 0.01 mol% or more, and the upper limit is usually 5 mol in all the components constituting the aliphatic polyester resin. % Or less, preferably 2.5 mol% or less.

  A preferred aliphatic polyester resin in the present invention is a polybutylene succinate resin, a polybutylene succinate adipate resin, or a mixture thereof. The meaning of “based resin” means that other constituent components may be contained in an amount of about 40 mol% or less. As the aliphatic polyester resin, polybutylene succinate, polybutylene succinate adipate, or a mixture thereof is particularly preferable.

  The content of the cyclic dimer contained in the aliphatic polyester resin contained in the aliphatic polyester resin composition of the present invention is essentially 1000 ppm to 10000 ppm by mass with respect to the entire aliphatic polyester resin, preferably It is 1500 ppm to 9000 ppm, particularly preferably 2000 ppm to 8000 ppm, and further preferably 2500 ppm to 7500 ppm. When the content of the cyclic dimer is too large, the amount of the organic compound containing a hydroxyl group necessary for suppressing the precipitation of the cyclic dimer is too large. There are cases where segregation occurs on the surface, and the fluidity of the resin becomes too high, causing problems during molding. On the other hand, if it is attempted to reduce the content of the cyclic dimer more than necessary, it is necessary to wash the resin using an appropriate solvent, as will be described later, and certainly the segregation of the cyclic dimer on the surface of the molded body. However, there are cases where the washing process with a solvent is complicated, and the solvent used for washing remains in the resin pellets. The content of the cyclic dimer in the present invention is a value determined by the method described in the examples.

  A method for adjusting the content of the cyclic dimer to 1000 ppm to 10000 ppm by mass with respect to the entire aliphatic polyester resin is not particularly limited. In the production process of the aliphatic polyester resin described later, the obtained resin is an extruder. There are a method of devolatilization while melting and extruding, and a method of washing an aliphatic polyester resin with an organic solvent after production. However, the method of washing an aliphatic polyester resin with an organic solvent after production has a problem that the production process becomes complicated and the used organic solvent remains in the resin.

  The aliphatic polyester resin used in the present invention can be produced by a known method. For example, a general method of melt polymerization in which an esterification reaction and / or a transesterification reaction between the aliphatic dicarboxylic acid component and the aliphatic diol component is performed, followed by a polycondensation reaction under reduced pressure, Although it can manufacture also by the well-known solution heating dehydration condensation method using a solvent, the method of manufacturing by melt polymerization performed without a solvent from a viewpoint of economical efficiency or the simplicity of a manufacturing process is preferable.

  The polycondensation reaction is preferably performed in the presence of a polymerization catalyst. The addition timing of the polymerization catalyst is not particularly limited as long as it is before the polycondensation reaction, and it may be added when the raw materials are charged, or may be added at the start of pressure reduction. The polymerization catalyst is generally a compound containing a group 1 to group 14 metal element excluding hydrogen and carbon in the periodic table. Specifically, at least one metal selected from the group consisting of titanium, zirconium, tin, antimony, cerium, germanium, zinc, cobalt, manganese, iron, aluminum, magnesium, calcium, strontium, sodium, and potassium. A carboxylate-containing salt, an alkoxy salt, an organic sulfonate, a compound containing an organic group such as a β-diketonate complex, an inorganic compound such as an oxide of a metal or a halide described above, or a mixture thereof.

  In these, the metal compound containing titanium, a zirconium, germanium, zinc, aluminum, magnesium, or calcium, and those mixtures are preferable, and especially a titanium compound or a germanium compound is preferable. In addition, the catalyst is preferably a compound that is liquid at the time of polymerization or that dissolves in the ester low polymer or the polyester because the polymerization rate is increased when the catalyst is melted or dissolved at the time of polymerization.

  The amount of catalyst added in the case of using a metal compound as the polymerization catalyst is such that the lower limit is usually 5 ppm or more, preferably 10 ppm or more, and the upper limit is usually 30000 ppm or less, preferably 1000 ppm, as the amount of metal relative to the produced polyester. Below, more preferably 250 ppm or less, particularly preferably 130 ppm or less. If too much catalyst is used, it is not only economically disadvantageous but also lowers the thermal stability of the polymer. Conversely, if it is too little, the polymerization activity is lowered, and as a result, the polymer decomposes during polymer production. Is more likely to be triggered.

  The lower limit of the esterification reaction and / or transesterification reaction temperature between the dicarboxylic acid component and the diol component is usually 150 ° C or higher, preferably 180 ° C or higher, and the upper limit is usually 260 ° C or lower, preferably 250 ° C or lower. The reaction atmosphere is usually an inert gas atmosphere such as nitrogen or argon. The reaction pressure is usually normal pressure to 10 kPa, but normal pressure is preferred. The reaction time is usually 1 hour or longer, and the upper limit is usually 10 hours or shorter, preferably 4 hours or shorter.

In the subsequent polycondensation reaction, the lower limit of the pressure is usually 0.001 × 10 ³ Pa or more, preferably 0.01 × 10 ³ Pa or more, and the upper limit is usually 1.4 × 10 ³ Pa or less, preferably 0. The degree of vacuum is 4 × 10 ³ Pa or less. The reaction temperature at this time has a lower limit of usually 150 ° C. or higher, preferably 180 ° C. or higher, and an upper limit of usually 260 ° C. or lower, preferably 250 ° C. or lower. The lower limit of the reaction time is usually 2 hours or more, and the upper limit is usually 15 hours or less, preferably 10 hours or less.

  In the present invention, a known vertical or horizontal stirred tank reactor can be used as a reactor for producing the aliphatic polyester resin. For example, melt polymerization is performed in two stages of esterification and / or transesterification and reduced pressure polycondensation using the same or different reactors, and a vacuum pump and a reactor are used as the reduced pressure polycondensation reactor. A method of using a stirred tank reactor equipped with a evacuation pipe for decompression to be connected can be mentioned. In addition, a condenser is connected between the vacuum exhaust pipe connecting the vacuum pump and the reactor, and the volatile components and unreacted monomers generated during the condensation polymerization reaction are recovered by the condenser. Is preferred.

  In the present invention, the molar ratio of the diol component and the dicarboxylic acid component for obtaining a polyester having a desired degree of polymerization differs in a preferred range depending on the purpose and the type of raw material, but the amount of the diol component relative to 1 mol of the acid component is The lower limit is usually 0.8 mol or more, preferably 0.9 mol or more, and the upper limit is usually 1.5 mol or less, preferably 1.3 mol or less, particularly preferably 1.2 mol or less. Moreover, a urethane bond, an amide bond, a carbonate bond, an ether bond, or the like can be introduced as long as the biodegradability is not affected.

  The aliphatic polyester resin used in the present invention has a sufficiently high crystallization rate, and the half-value width of the exothermic peak based on crystallization when cooled at 10 ° C./min in the differential scanning calorimetry is usually 15 C. or lower, preferably 10 ° C. or lower, particularly preferably 8 ° C. or lower. The differential scanning calorimeter is measured by using, for example, a Perkin Elmer DSC7, 10 mg of a sample is heated and melted in a nitrogen stream at a flow rate of 50 mL / min, cooled at a rate of 10 ° C./min, and accompanied with crystallization. This is done by recording the exothermic peak.

  When the melt flow rate (MFR) of the aliphatic polyester resin used in the present invention is measured at 190 ° C. and 2.16 kg, the lower limit is usually 0.1 g / 10 min or more, and the upper limit is usually 100 g / 10 min. Hereinafter, it is preferably 50 g / 10 min or less, particularly preferably 30 g / 10 min or less.

  The aliphatic polyester resin composition of the present invention may contain an aromatic aliphatic polyester resin. The “aromatic aliphatic polyester resin” is mainly composed of an aromatic dicarboxylic acid, an aliphatic dicarboxylic acid, and an aliphatic diol. In this case, the content of the aromatic dicarboxylic acid unit is preferably 5 mol% or more and 60 mol% or less based on the total amount of the aliphatic dicarboxylic acid unit and the aromatic dicarboxylic acid unit (100 mol%). Specifically, for example, an aliphatic diol unit represented by the following formula (3), an aliphatic dicarboxylic acid unit represented by the following formula (4), and an aroma represented by the following formula (5) Group dicarboxylic acid unit as an essential component. However, it may have an oxycarboxylic acid unit.

—O—R ³ —O— (3)
[In the formula (3), R ³ represents a divalent chain aliphatic hydrocarbon group and / or a divalent alicyclic hydrocarbon group, and is not limited to one type when copolymerized. ]
—OC—R ⁴ —CO— (4)
[In the formula (4), R ⁴ represents a direct bond or a divalent chain aliphatic hydrocarbon group and / or a divalent alicyclic hydrocarbon group. It is not limited to species. ]
—OC—R ⁵ —CO— (5)
[In Formula (5), R ⁵ represents a divalent aromatic hydrocarbon group, and is not limited to one type when copolymerized. ]

  The diol component giving the diol unit of the formula (3) is usually one having 2 to 10 carbon atoms, such as ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,4-cyclohexane. Examples include dimethanol. Among these, diols having 2 to 4 carbon atoms are preferable, ethylene glycol and 1,4-butanediol are more preferable, and 1,4-butanediol is particularly preferable.

  The dicarboxylic acid component that gives the dicarboxylic acid unit of the formula (4) usually has 2 to 10 carbon atoms, and examples thereof include succinic acid, adipic acid, suberic acid, sebacic acid, and dodecanedioic acid. Among these, succinic acid or adipic acid is preferable.

  Examples of the aromatic dicarboxylic acid component that gives the aromatic dicarboxylic acid unit of the formula (5) include terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid and the like, among which terephthalic acid and isophthalic acid are preferable, and terephthalic acid is particularly preferable. preferable. Moreover, aromatic dicarboxylic acid in which a part of the aromatic ring is substituted with a sulfonate is exemplified. Two or more types of aliphatic dicarboxylic acid components, aliphatic diol components, and aromatic dicarboxylic acid components can be used.

  The aromatic aliphatic polyester resin in the present invention may contain an aliphatic oxycarboxylic acid unit. Specific examples of the aliphatic oxycarboxylic acid that gives an aliphatic oxycarboxylic acid unit include lactic acid, glycolic acid, 2-hydroxy-n-butyric acid, 2-hydroxycaproic acid, 6-hydroxycaproic acid, 2-hydroxy-3, Examples include 3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, 2-hydroxyisocaproic acid, or a mixture thereof. Furthermore, these lower alkyl esters or intramolecular esters may be used. When optical isomers exist in these, any of D-form, L-form and racemic form may be sufficient, and a form may be any of solid, liquid, or aqueous solution. Among these, lactic acid or glycolic acid is preferable. These aliphatic oxycarboxylic acids can be used alone or as a mixture of two or more.

  The amount of the aliphatic oxycarboxylic acid is such that the lower limit is usually 0 mol% or more, preferably 0.01 mol% or more, and the upper limit is usually 30 mol% or less among all the components constituting the aromatic aliphatic polyester resin. , Preferably it is 20 mol% or less.

  The aromatic aliphatic polyester resin can be produced by the same production method as that for the aliphatic polyester resin.

  When the melt flow rate (MFR) of the aromatic aliphatic polyester resin used in the present invention is measured at 190 ° C. and 2.16 kg, the lower limit is usually 0.1 g / 10 min or more, and the upper limit is usually 100 g / 10. Min. Or less, preferably 50 g / 10 min or less, particularly preferably 30 g / 10 min or less.

  The content of the aromatic aliphatic polyester resin described above is preferably 1 part by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the aliphatic polyester resin. The lower limit of the content is more preferably 5 parts by mass or more, particularly preferably 10 parts by mass or more, and most preferably 20 parts by mass or more. The upper limit of the content is more preferably 70 parts by mass or less, particularly preferably 60 parts by mass or less. If the content of the aromatic aliphatic polyester resin is too large, the stiffness of the film is insufficient, and it may be necessary to increase the thickness of the film for use as various packaging materials. On the other hand, if the content of the aromatic aliphatic polyester resin is too small, the tensile elongation rate, tear strength, etc. may be insufficient.

<Starch>
The starch in the present invention is a carbohydrate (polysaccharide) having a molecular formula (C ₆ H ₁₀ O ₅ ) _n and is a natural polymer obtained by polymerizing a number of α-glucose molecules by glycosidic bonds or a modified product thereof. Here, “denaturation” includes all modifications such as chemical, physical and biological. Chemical modification indicates that some or all of the structural units of starch are modified by chemical reactions such as esterification, etherification, oxidation, reduction, coupling, dehydration, hydrolysis, dehydrogenation, halogenation, etc. In particular, it indicates that the hydroxyl group is etherified or esterified. Physical modification means changing physical properties such as changing the crystallinity. Biological degeneration refers to changing a chemical structure or the like using a living organism.

  Specific examples of the starch in the present invention include corn starch, waxy corn starch, high amylose corn starch, wheat starch, rice starch, potato starch, sweet potato starch, tapioca starch, pea starch, α starch and the like. Corn starch or potato Starch is preferred, and corn starch is particularly preferred.

  The starch content is arbitrary as long as the effects of the present invention are not significantly impaired, but is preferably 1% by mass or more and 60% by mass or less based on the total aliphatic polyester resin composition (100% by mass). The lower limit of the starch content is more preferably 5% by mass, still more preferably 10% by mass, and most preferably 15% by mass. The upper limit of the starch content is more preferably 50% by mass, still more preferably 45% by mass, and most preferably 40% by mass. When the starch content is less than 1% by mass, the physical property improving effect by starch may not be sufficiently exhibited. When the starch content exceeds 60% by mass, water resistance, hydrolysis resistance, flexibility, etc. are impaired. There is.

  Starch is plasticized by mixing with an organic compound containing a hydroxyl group, which will be described later, and optionally applying heat. "Plasticization" means that when the crystal structure contained in starch is destroyed, it can be melted and flowed when heated, and cooled, as with ordinary thermoplastic polymers Indicates a solidifying property. If starch is not plasticized, even if it is mixed with aliphatic polyester resin by melt kneading, starch behaves in the same way as ordinary organic and inorganic fillers. In addition, the mechanical properties and the like of the molded article made from the obtained aliphatic polyester resin composition are also inferior. That is, in order to obtain a molded article having good physical properties from a composition containing starch, it is necessary to plasticize the starch in the stage of obtaining the aliphatic polyester resin composition.

<Organic compound containing hydroxyl group>
The organic compound containing a hydroxyl group in the present invention is not particularly limited as long as it has a hydroxyl group. Can be mentioned. Among these, sorbitol, pentaerythritol, trimethylolpropane, trimethylolethane, ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-heptanediol, 1, 6-hexanediol, 1,8-octanediol, 1,9-nanonediol, 1,10-decanediol, 1,12-dodecanediol, diethylene glycol, triethylene glycol, polyethylene glycol, dipropylene glycol, tripropylene glycol , Polypropylene glycol, glycerol, glycerol monoalkyl ester, glycerol dialkyl ester, glycerol monoalkyl ether, glycerol dialkyl ether, diglycerol, diglycerol alkyl Ester etc., more preferably ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, glycerin, glycerin monoester, sorbitol or pentaerythritol, particularly preferably glycerin, sorbitol, pentaerythritol, propylene glycol or ethylene glycol . One or more organic compounds containing a hydroxyl group are used.

  The molecular weight of the organic compound containing a hydroxyl group is preferably 3000 or less, more preferably 2500 or less, and particularly preferably 2000 or less.

  The content of the organic compound containing a hydroxyl group is essentially 3% by mass to 40% by mass based on the entire aliphatic polyester resin (100% by mass). The upper limit with preferable content of the organic compound containing a hydroxyl group is 35 mass%, Most preferably, it is 30 mass%. On the other hand, the minimum with preferable content is 5 mass%, More preferably, it is 7 mass%, Most preferably, it is 10 mass%. When the content of the organic compound containing a hydroxyl group is too small, oligomers derived from the aliphatic polyester resin are precipitated on the surface, or the starch added to the aliphatic polyester is not sufficiently plasticized. In some cases, the mechanical properties may be degraded due to the fact that the film becomes unsatisfactory. On the other hand, when there is too much content of the organic compound containing a hydroxyl group, the organic compound containing a hydroxyl group may segregate on the surface of a molded object, and properties, such as surface appearance, may be impaired.

  Moreover, by containing the organic compound containing starch and a hydroxyl group with respect to the aliphatic polyester resin, and setting the content of the organic compound containing the hydroxyl group within the above range based on the entire aliphatic polyester resin. Even if the content of the cyclic dimer in the aliphatic polyester resin is 1000 ppm or more, precipitation of the cyclic dimer on the surface can be suppressed.

<Other ingredients>
In the present invention, a compatibilizer, an inorganic filler, an organic filler, a crystal nucleating agent, an antioxidant, an antiblocking agent, an ultraviolet absorber, a light-resistant agent, an antioxidant, a heat stabilizer, a colorant, a flame retardant, Release agents, antistatic agents, antifogging agents, surface wetting improvers, incineration aids, pigments, lubricants, dispersion aids, surfactants, slip agents, hydrolysis inhibitors, end-capping agents, etc. Ingredients "may be used. These can be arbitrarily used as long as the effects of the present invention are not impaired.

<Compatibilizer>
The aliphatic polyester resin composition of the present invention may contain a compatibilizing agent. The compatibilizing agent is an additive that improves the compatibility when the incompatible dissimilar resin or the starch and the resin are mixed. By adding a solubilizer, the compatibility can be improved.

  The compatibilizer is preferably added in an amount of 0.01% by mass or more and 10% by mass or less based on the total aliphatic polyester resin composition (100% by mass). The lower limit of the addition amount is more preferably 0.1% by mass or more, and further preferably 1% by mass or more. The upper limit of the addition amount is more preferably 5% by mass or less, further preferably 3% by mass or less, and particularly preferably 2% by mass or less.

  Examples of the compatibilizer include a polymer compatibilizer, a low molecular organic compound, an inorganic compound, an organic-inorganic composite, etc., but the polymer compatibilizer and the low molecular organic compound are molded products. From the viewpoint of physical properties, a polymer type compatibilizer is more preferable from the viewpoint of the molding process. The compatibilizer is preferably one having an acid anhydride group, glycidyl group or ether group structure, and a polymer type compatibilizer having any one of these structures is more preferred. By using a compatibilizing agent having these structures, the effect of improving the compatibility is increased.

  Polymeric compatibilizers include polyester, polyolefin, polyamide, polyether, polycarbonate, acrylic, styrene, urethane, polyacetal, olefin elastomer, unsaturated aliphatic elastomer, hydrogenated Examples thereof include resins such as unsaturated aliphatic elastomers, and two or more kinds of these blocks, grafts, or random copolymers. A polar group may be introduced into the molecule by further adding an unsaturated fatty acid anhydride to these copolymers. Maleic anhydride is preferably used as the unsaturated fatty acid anhydride to be added.

  Among these, polyester-based, polyolefin-based, polyamide-based, polyether-based, acrylic-based, styrene-based, olefin-based elastomers, unsaturated aliphatic elastomers, hydrogenated unsaturated aliphatic elastomers, and co-polymerization of two or more of these More preferred are coalesced and the like, and polyolefin-based, polyamide-based, polyether-based, acrylic-based, styrene-based, hydrogenated unsaturated aliphatic elastomers, and copolymers of two or more of these are more preferable.

  As a polyester-based compatibilizing agent, a polyester block or a random or graft containing a structure such as an aromatic polyester such as polyethylene terephthalate or polybutylene terephthalate, a polylactic acid, polycaprolactone, poly-3-hydroxybutyrate or the like as a part of the molecular structure Examples include copolymers

  Examples of the polyamide-based compatibilizer include 6 nylon, 6, 6 nylon, and 12 nylon. Examples of the polyether-based compatibilizer include polyethylene glycol, polypropylene glycol, and polytetramethylene glycol.

  Examples of the styrene type include polystyrene, poly p-methyl styrene, poly α-methyl styrene and the like. Examples of the olefin elastomer include ethylene propylene random copolymer and poly 1-butene. Examples of the unsaturated aliphatic elastomer include polybutadiene, polyisoprene, SBS, and SIS. Examples of the hydrogenated unsaturated aliphatic elastomer include SEBS and SEPS. Among polyolefin-based, polyamide-based, polyether-based, acrylic-based, styrene-based, hydrogenated unsaturated aliphatic elastomers and two or more types of these copolymers, polyolefin / glycidyl acrylate copolymers, Examples include polyolefin / glycidyl methacrylate copolymer, polyolefin / polyether copolymer, polyether ester amide, SEBS, maleic anhydride-modified SEBS, and the like.

<Inorganic filler>
You may mix | blend an inorganic filler with the aliphatic polyester resin composition of this invention. Examples of such inorganic fillers include silica, mica, talc, titanium oxide, calcium carbonate, diatomaceous earth, allophane, bentonite, potassium titanate, zeolite, sepiolite, smectite, kaolin, kaolinite, glass, limestone, carbon, wollastonite. , Calcined perlite, "silicates such as calcium silicate and sodium silicate", hydroxides such as aluminum oxide, magnesium carbonate, calcium hydroxide, ferric carbonate, zinc oxide, iron oxide, aluminum phosphate, barium sulfate, etc. Can be mentioned. These may be used alone or in combination of two or more.

  The amount of the inorganic filler contained in the aliphatic polyester resin composition of the present invention is not particularly limited, but the inorganic filler is 1 part by mass or more and 30 parts by mass with respect to 100 parts by mass of the aliphatic polyester resin composition. Or less, more preferably 3 parts by mass or more and 20 parts by mass or less, and particularly preferably 5 parts by mass or more and 15 parts by mass or less. If the amount of the inorganic filler is too small, the effect of improving the mechanical properties may be reduced. On the other hand, if the amount is too large, the moldability and impact resistance may be deteriorated.

<Organic filler>
Examples of the organic filler include pulp, chitin / chitosan, coconut shell powder, bamboo powder, bark powder, and powders such as kenaf and straw. These may be used alone or in combination of two or more. The content of the organic filler in the aliphatic polyester resin composition is preferably 60 parts by mass or less with respect to 100 parts by mass of the aliphatic polyester resin composition.

<Various additives>
The aliphatic polyester resin composition in the present invention can further contain various conventionally known additives. Examples of additives include crystal nucleating agents, antioxidants, anti-blocking agents, ultraviolet absorbers, light-resistant agents, plasticizers, heat stabilizers, colorants, flame retardants, mold release agents, antistatic agents, and antifogging agents. , Surface wettability improvers, incineration aids, pigments, lubricants, dispersion aids, various surfactants, slip agents, hydrolysis inhibitors and the like. These may be used alone or in combination of two or more. Among these, it is particularly preferable to add a slip agent and an antiblocking agent.

  The antifogging agent may be previously kneaded into the resin, or may be applied to the surface of the molded article after molding. Specifically, the antifogging agent used is preferably an ester surfactant of a saturated or unsaturated aliphatic carboxylic acid having 4 to 20 carbon atoms and a polyhydric alcohol. Examples of the slip agent include unsaturated fatty acid amides and unsaturated fatty acid bisamides composed of unsaturated fatty acids having 6 to 30 carbon atoms, most preferably erucic acid amide.

  Examples of the anti-blocking agent include saturated fatty acid amides having 6 to 30 carbon atoms, saturated fatty acid bisamides, methylol amides, ethanol amides, natural silicas, synthetic silicas, synthetic celite, talc and the like.

  Specific examples of the light stabilizer include bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, Bis (1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, 2- (3,5-di-t-butyl-4-hydroxyphenyl) -2-n-butyl-bis (2,2,6,6-tetramethyl-4-piperidyl) malonate, 2- (3,5-di-tert-butyl-4-hydroxyphenyl) -2-n-butyl-bis (1,2,2 , 6,6-pentamethyl-4-piperidyl) malonate, 2- (3,5-di-t-butyl-4-hydroxybenzyl) -2-n-butyl-bis (2,2,6,6-tetramethyl) -4-piperidyl) malonate, 2- 3,5-di-t-butyl-4-hydroxybenzyl) -2-n-butyl-bis (1,2,2,6,6-pentamethyl-4-piperidyl) malonate, tetrakis (2,2,6, 6-tetramethyl-4-piperidyl) -1,2,3,4-butanetetracarboxylate, tetrakis (1,2,2,6,6-pentamethyl-4-piperidyl) -1,2,3,4 Butanetetracarboxylate, mixed (2,2,6,6-tetramethyl-4-piperidyl / tridecyl) -1,2,3,4-butanetetracarboxylate, mixed (1,2,2,6, 6-pentamethyl-4-piperidyl / tridecyl) -1,2,3,4-butanetetracarboxylate, mixed {2,2,6,6-tetramethyl-4-piperidyl / β, β, β ′, β '− Tetramethyl-3,9- [2,4,8,10-tetraoxaspiro [5.5] undecane] diethyl} -1,2,3,4-butanetetracarboxylate, mixed {1,2,2 , 6,6-pentamethyl-4-piperidyl / β, β, β ′, β′-tetramethyl-3,9- [2,4,8,10-tetraoxaspiro [5.5] undecane] diethyl}- 1,2,3,4-butanetetracarboxylate, 1,2-bis (3-oxo-2,2,6,6-tetramethyl-4-piperidyl) ethane, 1- (3,5-di-t -Butyl-4-hydroxyphenyl) -1,1-bis (2,2,6,6-tetramethyl-4-piperidyloxycarbonyl) pentane, poly [1-oxyethylene (2,2,6,6-tetra Methyl-1,4-piperidyl) oxys Sinyl], poly [2- (1,1,4-trimethylbutylimino) -4,6-triazinediyl- (2,2,6,6-tetra and -4-piperidyl) iminohexamethylene- (2,2 , 6,6-tetramethyl-4-piperidyl) imino], N, N′-bis (3-aminopropyl) ethylenediamine-2,4-bis [N-butyl-N- (2,2,6,6- Tetramethyl-4-piperidyl) amino] -6-chloro-1,3,5-triazine condensate and its N-methyl compound, succinic acid and 1- (2-hydroxyethyl) -4-hydroxy-2,2, Examples include polycondensates with 6,6-tetramethylpiperidine.

  Among these, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, 2- (3,5-di-t-butyl-4-hydroxybenzyl) -2-n-butyl- Bis (1,2,2,6,6-pentamethyl-4-piperidyl) malonate is particularly preferred.

  Examples of the UV absorber that may be added to the aliphatic polyester resin composition of the present invention include benzotriazole UV absorbers among UV absorbers such as benzophenone, benzotriazole, salicylic acid, and cyanoacrylate. Specifically, specifically, 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, 2- (4,6-diphenyl-1,3,5- And triazin-2-yl) -5-hexyloxy-phenol.

  Antioxidants that may be added to the aliphatic polyester resin composition of the present invention include BHT, 2,2′-methylenebis (4-methyl-6-tert-butylphenol), pentaerythritol tetrakis [3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate], 3,3 ′, 3 ″, 5,5 ′, 5 ″ -hexatert-butyl-α, α ′, α ″-(mesitylene-2, 4,6-triyl) tri-p-cresol, octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 1,3,5-tris [(4-tert-butyl-3 -Hydroxy-2,6-xylyl) methyl] -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, 1,3,5-tris (3,5-di-ter -Butyl-4-hydroxybenzyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, calcium diethylbis [{3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl} methyl] phosphonate, bis (2,2′-dihydroxy-3,3′-di-tert-butyl-5,5′-dimethylphenyl) ethane, N, N′-hexane-1,6 Hindered phenolic antioxidants such as diylbis [3- (3,5-di-tert-butyl) -4-hydroxyphenyl] propionamide, tridecyl phosphite, diphenyldecyl phosphite, tetrakis (2,4- Di-tert-butylphenyl) [1,1-biphenyl] -4,4′-diylbisphosphonite, bis [2,4-bis (1,1-dimethyl) (Ruethyl) -6-methylphenyl] ethyl ester phosphorous acid, phosphorous antioxidants such as bis (2,4-di-tert-butylphenyl) pentaerythritol diphosphite, 3-hydroxy-5,7-di- lactone-based antioxidants such as tert-butyl-furan-2-one and xylene reactive organisms, sulfur-based antioxidants such as dilauryl thiodipropionate, distearyl thiodipropionate, and two or more of these A mixture etc. can be illustrated.A hindered phenolic antioxidant is used suitably among these.

  Preferred hindered phenolic antioxidants include Irganox 3790, Irganox 1330, Irganox 1010, Irganox 1076, Irganox 3114, Irganox 1425WL, Irganox 1098, Irganox HP2225FL, Irganox HP2341, Irgaphos XP-30. (Above, manufactured by Ciba Specialty Chemicals Co., Ltd.) and Sumilyzer BBM-S (manufactured by Sumitomo Chemical Co., Ltd.) are used. The most preferred antioxidant is Irganox 3790 (1,3,5-tris [(4-tert-butyl-3-hydroxy-2,6-xylyl) methyl] -1,3,5-triazine-2,4, 6 (1H, 3H, 5H) -trione), Irganox 1330 (3,3 ′, 3 ″, 5,5 ′, 5 ″ -hexa-tert-butyl-α, α ′, α ″-(mesitylene-2) , 4,6-triyl) tri-p-cresol).

  The addition amount of these additives is usually 0.001% by mass or more and 10% by mass or less based on the total aliphatic polyester resin composition (100% by mass). The lower limit of the addition amount is preferably 0.01% by mass or more, more preferably 0.1% by mass or more. The upper limit of the addition amount is preferably 5% by mass or less, more preferably 3% by mass or less. The aliphatic polyester resin composition of the present invention can also contain a freshness-keeping agent, an antibacterial agent and the like as a functional additive.

  Examples of the terminal blocking agent include carbodiimide compounds, epoxy compounds, oxazoline compounds, etc. Among them, carbodiimide compounds are preferably used.

<Carbodiimide compound>
In the present invention, a carbodiimide compound can be suitably used mainly for the purpose of suppressing hydrolysis due to moisture in the atmosphere. The carbodiimide compound used is a compound (including a polycarbodiimide compound) having one or more carbodiimide groups in the molecule, and such a carbodiimide compound uses, for example, an organophosphorus compound or an organometallic compound as a catalyst, It can be synthesized by subjecting an isocyanate compound to a decarboxylation condensation reaction in a solvent-free or inert solvent at a temperature of 70 ° C. or higher.

  Among the above carbodiimide compounds, the monocarbodiimide compounds include dicyclohexylcarbodiimide, diisopropylcarbodiimide, dimethylcarbodiimide, diisobutylcarbodiimide, dioctylcarbodiimide, t-butylisopropylcarbodiimide, diphenylcarbodiimide, di-t-butylcarbodiimide, and di-β-naphthylcarbodiimide. Etc. can be illustrated. Of these, dicyclohexylcarbodiimide and diisopropylcarbodiimide are preferred because they are easily available industrially. Examples of the polycarbodiimide compound include U.S. Pat. No. 2,941,956, Japanese Patent Publication No. 47-33279, J. Pat. Org. Chem. 28, p2069-2075 (1963), and Chemical Review 1981, 81, No. 4, p. 619-p. What was manufactured by the method described in 621 grade | etc., Can be used.

  In the present invention, a polycarbodiimide compound may be used. The lower limit of the degree of polymerization is 2 or more, preferably 4 or more, and the upper limit is usually 40 or less, preferably 20 or less. If the degree of polymerization is too large, dispersibility in the composition becomes insufficient, which may cause poor appearance in, for example, an inflation film.

  The carbodiimide compound may be added during the preparation of the aliphatic polyester resin composition described later, or is kneaded and molded into one or two kinds of polyesters among aliphatic polyester resins and aromatic aliphatic polyester resins. Sometimes, it may be molded by mixing with all components of the aliphatic polyester resin composition by dry blending with other components. Alternatively, a master batch of a high concentration carbodiimide compound is prepared with an aliphatic polyester resin and / or an aromatic aliphatic polyester resin, and the aliphatic polyester resin and / or so that the carbodiimide compound has a predetermined concentration at the time of molding. An aromatic aliphatic polyester resin and starch may be dry blended and diluted.

<Other ingredients>
The aliphatic polyester resin composition of the present invention includes biodegradable resins and natural products within a range not inhibiting the effects of the present invention, such as polylactic acid, polycaprolactone, polyamide, polyvinyl alcohol, cellulose ester, cellulose, paper, Fine powders of animal / plant substances such as wood powder, chitin / chitosan, coconut shell powder, walnut shell powder, or a mixture thereof can be blended.

<Kneading and molding method>
[Kneading method]
In the present invention, all conventionally known mixing / kneading techniques can be applied. As the mixer, a horizontal cylindrical type, V-shaped, double-cone type mixer, a blender such as a ribbon blender or a super mixer, various continuous mixers, or the like can be used. Moreover, as a kneading machine, a batch type kneading machine such as a roll or an internal mixer, a one-stage type, a two-stage type continuous kneading machine, a twin screw extruder, a single screw extruder, or the like can be used.

  The method for preparing the aliphatic polyester resin composition of the present invention is not particularly limited, and examples thereof include a method in which the blended raw materials are melt-mixed in the same extruder, a method in which the raw materials are melted in separate extruders, and the like. . Moreover, it is also possible to obtain the molded article at the same time as preparing the aliphatic polyester resin composition by supplying each raw material directly to the molding machine. A method of adding and blending various additives, inorganic fillers, organic fillers, the above-mentioned “other components”, other polyesters, etc. when the components are mixed and heated and melted. At this time, blending oil or the like can also be used for the purpose of uniformly dispersing the various additives.

  When melt-mixing with an extruder, the temperature of the aliphatic polyester resin composition in the extruder is preferably 50 ° C. or higher and 150 ° C. or lower, depending on the type of aliphatic polyester resin and starch used. More preferably, it is 70 degreeC or more and 140 degrees C or less. When the temperature of the aliphatic polyester resin composition is higher than 150 ° C., the starch in the composition may be deteriorated, the composition is colored, the load on the extruder is increased, and the inside of the extruder is increased. Problems such as blockage of the composition may occur. In addition, when the temperature of the aliphatic polyester resin composition is lower than 50 ° C., the starch plasticization by the “organic compound containing a hydroxyl group” may not sufficiently proceed. May become insufficient, and the appearance and the like of a molded product produced from the resulting aliphatic polyester resin composition may be deteriorated.

  In the present invention, from the content of the cyclic dimer actually present in the entire aliphatic polyester resin composition obtained by analyzing the aliphatic polyester resin composition, considering the blending mass ratio of each raw material, The “content of cyclic dimer contained per aliphatic polyester resin”, which was converted as if all cyclic dimers were contained in the aliphatic polyester resin, was obtained by analyzing the aliphatic polyester resin itself as a raw material. This is almost the same as “the content of the cyclic dimer contained in the aliphatic polyester resin”. In other words, the content of the cyclic dimer present in the aliphatic polyester resin composition takes into consideration the blending mass ratio of each raw material from the content of the cyclic dimer contained in the aliphatic polyester resin as the raw material. It is almost the same as the content of the cyclic dimer when calculated as follows. That is, in the preparation of an aliphatic polyester resin composition composed of an aliphatic polyester resin, starch and a hydroxyl group-containing organic compound as described later, the cyclic dimer contained in the aliphatic polyester resin is obtained without volatilization or the like. It is contained as it is in the obtained aliphatic polyester resin composition. In the present invention, the content of the cyclic dimer in the aliphatic polyester resin and the content of the cyclic dimer in the aliphatic polyester resin composition are values determined by the method described in the examples.

[Molding method]
The aliphatic polyester resin composition in the present invention can be subjected to molding by various molding methods applied to general-purpose plastics. The molding methods include, for example, compression molding (compression molding, laminate molding, stampable molding), injection molding, extrusion molding and coextrusion molding (film molding by inflation method or T-die method, laminate molding, pipe molding, electric wire / cable molding. , Profile molding), hollow molding (various blow molding), calendar molding, foam molding (melt foam molding, solid phase foam molding), solid molding (uniaxial stretching molding, biaxial stretching molding, roll rolling molding, stretch oriented nonwoven fabric Examples thereof include molding, thermoforming (vacuum forming, pressure forming), plastic working), powder forming (rotary forming), various non-woven fabric forming (dry method, adhesion method, entanglement method, spunbond method, etc.). Among these, extrusion molding, injection molding, foam molding, and hollow molding are preferably applied. As a specific shape, application to a film, a container and a fiber is preferable. Since the aliphatic polyester resin composition of the present invention has good melting characteristics and mechanical properties, it is preferably used for products produced from a film formed by inflation molding, and further from a film formed by inflation molding.

  In the present invention, the content of the cyclic dimer present in the molded body is almost the same as the content of the cyclic dimer contained in the aliphatic polyester resin composition before molding. That is, at the time of molding, the cyclic dimer contained in the aliphatic polyester resin composition is contained in the obtained molded body without volatilization or the like. However, if it is deposited on the surface of the molded body, the mass of the deposited cyclic dimer is also added to the above comparison. In the present invention, the content of the cyclic dimer in the molded body is a value determined by the method described in the examples.

<Physical properties of molded body>
When the molded body is a film having a thickness of 30 μm, the tensile elastic modulus in the direction parallel to the flow of the resin is not particularly limited, but is preferably 10 to 700 MPa, more preferably 30 to 600 MPa. 50 to 500 MPa is particularly preferable, and 80 to 400 MPa is more preferable. If the tensile modulus is too low, it may not be able to withstand the weight of the contents depending on the thickness of the film when used as a packaging material for garbage bags, shopping bags, shopping bags, compost bags and the like. Moreover, when too large, the flexibility of a film may be impaired and usability may worsen.

  The Elmendorf tear strength in the direction parallel to the flow of the resin when formed into a film having a thickness of 30 μm is not particularly limited, but is preferably 1 N / mm or more, more preferably 2 N / mm or more. Particularly preferably, it is 3 N / mm or more, and most preferably 5 N / mm. If the Elmendorf tear strength is less than 1 N / mm, there may be practical problems as packaging materials for garbage bags, shopping bags, shopping bags, compost bags, and the like.

  The film made of the starch-containing composition produced by the production method of the present invention preferably has a weight loss of 5% or more in horticultural soil in an environment of 50 ° C. over 8 days. A more preferable weight loss rate is 8% or more, and most preferably 10% or more. If the weight loss rate is less than 5% in 8 days, the film may remain in the soil for a long time when discarded, whereas the film with a low initial weight loss rate may not be completely biodegraded. .

  Also, these molded products are provided with chemical functions, electrical functions, magnetic functions, mechanical functions, friction / wear / lubricating functions, optical functions, thermal functions, surface functions such as biocompatibility, etc. For this purpose, it is also possible to perform various purposeful secondary processing. Examples of secondary processing include embossing, painting, adhesion, printing, metalizing (plating, etc.), machining, surface treatment (antistatic treatment, corona discharge treatment, plasma treatment, photochromism treatment, physical vapor deposition, chemical vapor deposition, Coating) and the like.

<Application>
Since the aliphatic polyester resin composition of the present invention has good moldability and mechanical strength and the precipitation of oligomers derived from the aliphatic polyester resin on the surface is suppressed, the aliphatic polyester resin composition of the present invention Molded articles formed by molding products are suitably used in a wide range of applications such as various foods, drugs, miscellaneous liquids and powders, solid packaging materials, agricultural materials, and building materials. Specific applications include injection molded products (for example, fresh food trays, fast food containers, outdoor leisure products, etc.), extruded products (films, such as fishing lines, fishing nets, vegetation nets, water retaining sheets, etc.), hollow molding. Products (bottles, etc.), other agricultural films, coating materials, fertilizer coating materials, laminate films, plates, stretched sheets, monofilaments, non-woven fabrics, flat yarns, staples, crimped fibers, striped tape, Split yarn, composite fiber, blow bottle, foam, shopping bag, garbage bag, compost bag, cosmetic container, detergent container, bleach container, rope, binding material, sanitary cover stock material, cold box, cushion material film, multi Filament, synthetic paper, surgical thread, suture, artificial bone, artificial skin for medical use, Microcapsules etc. DDS of wound dressing and the like.

  The aliphatic polyester resin composition of the present invention is produced from a film formed by inflation molding because it has good moldability and mechanical strength, and the precipitation on the surface of the oligomer derived from the aliphatic polyester resin is suppressed. It is preferable to be applied to shopping bags or garbage bags.

  In addition, information electronic materials such as toner binders and thermal transfer ink binders, automotive interior parts such as electrical product casings, instrument panels, sheets and pillars, and automotive exterior structural materials such as bumpers, front grills and wheel covers. Can be used. More preferably, packaging materials such as packaging films, bags, trays, bottles, cushioning foams, fish boxes, etc., and agricultural materials such as mulching films, tunnel films, house films, sun coverings, grass protections. Sheets, cocoon sheets, germination sheets, vegetation mats, nursery beds, flower pots and the like can be mentioned.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples unless it exceeds the gist.

<1. Physical property evaluation>
[1.1. Evaluation of content of cyclic dimer]
Liquid chromatography “LC-10A” manufactured by Shimadzu Corporation was used, the mobile phase was acetonitrile / water (volume ratio 4/6), and the column was “SHISEIDOCAPELL PAK C-18 TYPE MG” manufactured by Shiseido Co., Ltd. The content (ppm by mass) of the cyclic dimer contained in the resin and the aliphatic polyester resin composition was quantified.

[1.2. Evaluation of oligomer precipitation]
The film made of the obtained aliphatic polyester resin composition was stored for 1 month under the conditions of 23 ° C. and 50% RH, and the subsequent film appearance was visually observed and evaluated according to the following criteria.
Good (O): No white precipitate due to the cyclic dimer is visually confirmed on the surface of the film.
Defect (x): The white deposit resulting from a cyclic dimer can be visually confirmed on the surface of a film.

[1.3. Evaluation of surface properties]
The film made of the obtained aliphatic polyester resin composition was evaluated visually and by hand, and evaluated according to the following criteria.
Good (O): No bleed-out to the surface of starch agglomerates or organic compounds containing hydroxyl groups.
Poor (x): Bleed-out to the surface of starch agglomerates and organic compounds containing hydroxyl groups is observed.

[1.4. Evaluation of film formability]
The ease of molding when performing inflation molding was evaluated according to the following criteria.
Good (O): It is possible to mold to a predetermined thickness (30 μm) at a predetermined temperature (160 ° C.).
Defect (x): It is impossible to mold to a predetermined thickness (30 μm) at a predetermined temperature (160 ° C.).

<2. Production of resin composition>
[2.1. Aliphatic polyester resin]
The aliphatic polyester resins (A-1), (A-2) and (A-3) described below were used as the aliphatic polyester resins.

[Aliphatic polyester resin (A-1)]
As the aliphatic polyester resin (A-1), polybutylene succinate resin GS Pla (grade name: AZ91TN) manufactured by Mitsubishi Chemical Corporation was used. The content of the cyclic dimer contained in the resin was 7900 ppm.

[Production Example 1 (Production Method of Aliphatic Polyester Resin (A-2))]
With respect to 100 parts by mass of the aliphatic polyester (A-1), 200 parts by mass of acetone was charged in a reaction vessel, and the temperature was raised to 50 ° C. and left for 5 hours. After completion of the washing, the washing liquid was filtered under the atmosphere to separate and collect the wet pellet and the washing filtrate. The wet pellet was vacuum dried at 80 ° C. for 15 hours to obtain an aliphatic polyester resin (A-2). The content of the cyclic dimer measured by the method described above was 4500 ppm.

[Production Example 2 (Production Method of Aliphatic Polyester Resin (A-3))]
In Production Example 1, an aliphatic polyester resin (A-3) was obtained in the same manner as in Production Example 2, except that the standing time at the time of acetone washing was 12 hours. The measured cyclic dimer content was 580 ppm.

[2-2. starch]
As starch, corn starch (manufactured by Nippon Corn Starch; Y-3P) was used.

[2-3. Organic compound containing hydroxyl group]
Glycerin was used as an organic compound containing a hydroxyl group.

[2-4. Others]
As the other resin, an aromatic aliphatic polyester resin (Ecoflex: polybutylene terephthalate adipate manufactured by BASF) was used.

Example 1
Supply cornstarch (Japan Cornstarch Y-3P; moisture content 12%) 100 parts by mass and glycerin 50 parts by mass to a screw type twin screw extruder (Nippon Steel Works TEX30; 22 cylinders, L / D = 77). Then, after passing through the step of mixing so that the maximum temperature becomes 150 ° C. or less, the same step of supplying 225 parts by mass of aliphatic polyester resin (A-1) and mixing corn starch, glycerin and resin is the same. A white resin composition was obtained by sequentially performing in an extruder. Thereafter, pellets of the resin composition were dried at 70 ° C. in a nitrogen atmosphere for 8 hours. The content of the cyclic dimer measured by the above-described method was 4520 ppm with respect to the entire resin composition. When converted per aliphatic polyester resin (A-1) in the resin composition, it was 7540 ppm, and the amount of the cyclic dimer did not change significantly in the extrusion step.

  The obtained aliphatic polyester resin composition was subjected to inflation molding at a molding temperature of 160 ° C. using an inflation molding machine to form a film having a thickness of 30 μm. The resulting film was translucent white with no foreign matter such as aggregates, and no oligomer precipitation was observed even at 1 month under conditions of 23 ° C. and 50% RH. The results are shown in Table 1.

Example 2
In Example 1, 169 parts by mass of the aliphatic polyester resin (A-1) and 56 parts by mass of the aromatic aliphatic polyester resin (manufactured by BASF; Ecoflex) were melt kneaded in the same manner as in Example 1. Thus, a resin composition was obtained. The content of the cyclic dimer measured by the above-described method was 3480 ppm with respect to the entire resin composition. When converted to the aliphatic polyester resin (A-1) in the resin composition, it was 7740 ppm, and the amount of the cyclic dimer did not change greatly in the extrusion process.

  Film formation was carried out in the same manner as in Example 1. The resulting film was translucent white with no foreign matter such as aggregates, and no oligomer precipitation was observed even at 1 month under conditions of 23 ° C. and 50% RH. The results are shown in Table 1.

Example 3
In Example 1, except that the aliphatic polyester resin was 225 parts by mass of the aliphatic polyester resin (A-2) obtained in Production Example 1, the resin composition was melt-kneaded in the same manner as in Example 1. Got. The content of the cyclic dimer measured by the method described above was 2630 ppm with respect to the entire resin composition. It was 4390 ppm when converted per aliphatic polyester resin (A-2) in the resin composition, and the amount of the cyclic dimer did not change significantly in the extrusion step.

  Film formation was carried out in the same manner as in Example 1. The resulting film was translucent white with no foreign matter such as aggregates, and no oligomer precipitation was observed even at 1 month under conditions of 23 ° C. and 50% RH. The results are shown in Table 1.

Example 4
In Example 1, except that the corn starch was 100 parts by mass, the glycerin was 30 parts by mass, and the aliphatic polyester resin (A-2) was 195 parts by mass, the resin composition was melt kneaded in the same manner as in Example 1. Obtained. The content of the cyclic dimer measured by the method described above was 2650 ppm with respect to the entire resin composition. When converted per aliphatic polyester resin (A-2) in the resin composition, it was 4420 ppm, and the amount of the cyclic dimer did not change significantly in the extrusion process.

  Film formation was carried out in the same manner as in Example 1. The resulting film was translucent white with no foreign matter such as aggregates, and no oligomer precipitation was observed even at 1 month under conditions of 23 ° C. and 50% RH. The results are shown in Table 1.

Example 5
In Example 1, except that the corn starch was 100 parts by mass, the glycerin was 33 parts by mass, and the aliphatic polyester resin (A-2) was 533 parts by mass, the resin composition was melt kneaded in the same manner as in Example 1. Obtained. The content of the cyclic dimer measured by the above-described method was 3310 ppm with respect to the entire resin composition. When converted to the aliphatic polyester resin (A-2) in the resin composition, it was 4140 ppm, and the amount of the cyclic dimer was not significantly changed in the extrusion process.

  Film formation was carried out in the same manner as in Example 1. The resulting film was translucent white with no foreign matter such as aggregates, and no oligomer precipitation was observed even at 1 month under conditions of 23 ° C. and 50% RH. The results are shown in Table 1.

Comparative Example 1
Inflation molding was performed on 100 parts by mass of the aliphatic polyester resin (A-1) under the same conditions as in Example 1 to obtain a film having a thickness of 30 μm. The resulting film was translucent with no foreign matter such as aggregates, but a large amount of oligomers was observed when placed under 23 ° C. and 50% RH for 1 month. The results are shown in Table 1.

Comparative Example 2
100 parts by mass of the aliphatic polyester resin (A-2) obtained in Production Example 1 was subjected to inflation molding under the same conditions as in Example 1 to obtain a film having a thickness of 30 μm. The resulting film was translucent with no foreign matter such as aggregates, but a large amount of oligomers was observed when placed under 23 ° C. and 50% RH for 1 month. The results are shown in Table 1.

Comparative Example 3
100 parts by mass of the aliphatic polyester resin (A-3) obtained in Production Example 2 was subjected to inflation molding under the same molding conditions as in Example 1 to obtain a film having a thickness of 30 μm. The obtained film was translucent without foreign matter such as aggregates. When placed under conditions of 23 ° C. and 50% RH for 1 month, the surface condition was good without oligomer precipitation. However, since 12 hours of acetone cleaning was performed in the manufacturing process of the aliphatic polyester resin (A-3), the productivity of the resin composition was lowered, the cleaning cost was increased, and there was an obstacle that there was an acetone odor. was there. The results are shown in Table 1.

Comparative Example 4
A resin composition was obtained by melt-kneading in the same manner as in Example 1 except that 1125 parts by weight of the aliphatic polyester resin (A-1), 100 parts by weight of corn starch, and 25 parts by weight of glycerin were used in Example 1. . The content of the cyclic dimer measured by the above-described method was 6840 ppm with respect to the entire resin composition. It was 7600 ppm when converted per aliphatic polyester resin (A-1) in the resin composition, and the amount of the cyclic dimer did not change greatly in the extrusion process.

  Film formation was carried out in the same manner as in Example 1. The obtained film had many agglomerates derived from starch, and was a sample with poor appearance that could not be blow-molded at a thickness of 30 μm (sampled at a thickness of 60 μm). When placed under a condition of 23 ° C. and 50% RH for 1 month, a large amount of oligomers was precipitated. The results are shown in Table 1.

Comparative Example 5
A resin composition was obtained by melt-kneading in the same manner as in Comparative Example 4, except that 100 parts by weight of the aliphatic polyester resin (A-1), 100 parts by weight of corn starch, and 50 parts by weight of glycerin were used in Comparative Example 4. . The content of the cyclic dimer measured by the method described above was 3100 ppm with respect to the entire resin composition. When converted to the aliphatic polyester resin (A-1) in the resin composition, it was 7750 ppm, and the amount of the cyclic dimer did not change greatly in the extrusion process.

  Since the fluidity of the resin composition was increased by adding a large amount of glycerin, inflation molding was impossible at a thickness of 30 μm (sampling at a thickness of 60 μm). The film surface was sticky due to glycerin bleedout. When placed under conditions of 23 ° C. and 50% RH for 1 month, no oligomer precipitation was observed. The results are shown in Table 1.

Comparative Example 6
In Example 1, instead of using 225 parts by mass of the aliphatic polyester resin (A-1), Example 1 except that 225 parts by mass of the aliphatic polyester resin (A-3) obtained in Production Example 2 was used. The resin composition was obtained by melt-kneading under the same conditions. The content of the cyclic dimer measured by the method described above was 310 ppm with respect to the entire resin composition. When converted to the aliphatic polyester resin (A-3) in the resin composition, it was 520 ppm, and the amount of the cyclic dimer did not change greatly in the extrusion process.

  Inflation molding was performed in the same manner as in Example 1 to obtain a film having a thickness of 30 μm. The obtained film was translucent without foreign matter such as aggregates. When placed under conditions of 23 ° C. and 50% RH for 1 month, the surface condition was good without oligomer precipitation. However, in the production process of the aliphatic polyester resin (A-3), acetone washing for 12 hours was carried out, so that there was an obstacle that there was an acetone odor. In addition, the productivity of the resin composition is lowered, and there are also obstacles in that the cleaning cost is increased. The results are shown in Table 1.

表１中、脂肪族ポリエステル樹脂の下の括弧内の数字は、脂肪族ポリエステル樹脂を分析した際の脂肪族ポリエステル樹脂全体に対する環状２量体の含量（質量ｐｐｍ）を示す。また、表１中の数字は質量部を示す。

In Table 1, the numbers in parentheses under the aliphatic polyester resin indicate the content (mass ppm) of the cyclic dimer with respect to the entire aliphatic polyester resin when the aliphatic polyester resin is analyzed. Moreover, the number in Table 1 shows a mass part.

  Since the aliphatic polyester resin composition of the present invention and the molded product thereof are excellent in mechanical properties, moldability, and mechanical strength, it is used for packaging liquids, powders, and solids for various foods, medicines, miscellaneous goods, etc. It is widely used for materials, agricultural materials, building materials, etc.

Claims (6)

An aliphatic polyester resin containing a diol unit and a dicarboxylic acid unit, a film formed from an aliphatic polyester resin composition containing at least an organic compound containing starch and a hydroxyl group, wherein the starch content is the fat With respect to the whole group polyester resin composition (100% by mass), it is 5% by mass or more and 40% by mass or less, and the compounding amount of the organic compound containing the hydroxyl group is based on 100 parts by mass of the aliphatic polyester resin. 3 or less parts by mass or more 40 parts by weight, the content of cyclic dimer contained in the aliphatic polyester resin is characterized by a range of 1000~10000ppm film. The film according to claim 1, wherein the organic compound containing a hydroxyl group has a molecular weight of 3000 or less. The film according to claim 1 or 2 , wherein the aliphatic polyester resin is a polybutylene succinate resin, a polybutylene succinate adipate resin, or a mixture thereof. The film according to any one of claims 1 to 3 , wherein the organic compound containing a hydroxyl group is at least one selected from the group consisting of glycerin, sorbitol, pentaerythritol, propylene glycol, and ethylene glycol. . A film according to any one of claims 1 to claim 4 is made by inflation molding the aliphatic polyester resin composition. A garbage bag or a shopping bag manufactured from the film according to claim 5 .