JP5608540B2 - Method for producing polylactic acid resin composition - Google Patents

Description

  The present invention relates to a method for producing a polylactic acid resin composition.

  When producing a resin molded product from a thermoplastic resin, for example, a pellet-shaped resin composition is generally used as a molding material. And this resin composition is normally manufactured with an extruder.

  As a method for producing a resin composition using an extruder, for example, Patent Document 1 uses a same-direction meshing twin screw extruder, and a cylinder is provided with a vent port at a position away from a feed opening by a predetermined length. The screw between them consists of a solid transport part, a solid compression part, a shear part, and a volatile separation part each having a predetermined length in order from the feed opening side. It is disclosed that the solvent is separated from the vent port by setting the melting point Tm-50) to (Tm + 90) ° C. or (the glass transition temperature Tg of the thermoplastic resin) to (Tg + 120) ° C.

  In Patent Document 2, a solid transport zone, a mixing zone, and a melting zone are used by a screw element installed between a material supply port and an outlet using a same-direction meshing twin screw extruder. Then, the kneading temperature in each zone is set in a temperature range 0 to 50 ° C. higher than the melting point Tm of the resin or in a temperature range 80 to 150 ° C. higher than the glass transition temperature Tg. It is disclosed that kneading is performed while sequentially passing through these zones.

  In addition, biodegradable resin materials have attracted attention due to the recent increase in interest in environmental problems.

  For example, in Patent Document 3, a metal hydroxide having an average particle size of 7 μm or less, which has been surface-treated with an epoxy silane coupling agent, is added to 20 to 100 parts by weight of a lactic acid resin that is a biodegradable resin material. An injection molded body containing 120 parts by weight is disclosed.

JP 2001-047496 A JP 2008-155570 A JP 2004-263180 A

  An object of the present invention is to obtain excellent flexibility and heat resistance in a polylactic acid resin composition.

The present invention provides a mixture including a polylactic acid resin and a surface-treated inorganic powder having a content of 50 to 200 parts by weight with respect to 100 parts by weight of the polylactic acid resin. A pair of screws having an outer diameter D of 30 mm or more in which screw elements are continuously provided along the length direction are barrels that are divided into a plurality of parts that can be independently set in temperature along the length direction. The length of the downstream part from the position corresponding to the center of the raw material supply port of the barrel among the screw effective parts that are inserted in parallel and the screw elements of the screw are continuously arranged along the length direction. Polylactic acid resin kneaded using the same direction meshing twin screw extruder having a ratio of L to the outer diameter D of the screw of 30 or more (L / D) satisfying the following conditions 1 to 3 It is a manufacturing method of forming compounds.
Condition 1: It is provided so as to include at least the range of 6.3D to 13Dmm from the center position of the raw material supply port of the barrel, and the set temperature of the barrel is (Tm + 50) to (Tm + 80) where the melting point of the polylactic acid resin is Tm A first temperature setting zone in which the screw is provided with a conveying element, and a range of at least 19.3 Dmm from the center position of the barrel material supply port on the downstream side of the first temperature setting zone. And a second temperature setting zone in which the set temperature of the barrel is (Tm−20) to (Tm + 40) ° C.
Condition 2: It is provided to have a start point and an end point within a range of 13D to 20.9Dmm from the center position of the raw material supply port of the barrel, the length is 1D to 4Dmm, and the kneading element is provided to the screw It has a 1st kneading part.
Condition 3: Second kneading provided with a starting point within a range of 20.9 Dmm or more from the center position of the raw material supply port of the barrel, a length of 1 D to 4 D mm, and a kneading element provided on the screw Part.

  According to the present invention, when the mixture containing the polylactic acid resin and the surface-treated inorganic powder is kneaded using the same-direction meshing twin screw extruder, the specific first and specific second temperature settings are performed. By providing the zone and the first and second kneading sections, excellent flexibility and heat resistance can be obtained in the produced polylactic acid resin composition.

The same direction meshing type twin screw extruder which concerns on embodiment is shown. It is a top view which shows the inside of a barrel. It is sectional drawing which shows a barrel inside.

  Hereinafter, embodiments will be described in detail.

(Same direction meshing twin screw extruder)
FIG. 1 shows a same-direction meshing twin-screw extruder 100 according to this embodiment.

  The same-direction meshing twin-screw extruder 100 according to the present embodiment has a pair of screws 10 and a barrel 20, and the pair of screws 10 are arranged in parallel in the horizontal direction and inserted through the barrel 20. It is provided to be rotatable in the direction. The pair of screws 10 are configured to rotate in the same direction so as to convey and knead the raw material from the upstream side to the downstream side through a gap formed between the screw 10 and the inner wall of the barrel 20.

  A raw material supply unit 30 is provided at the upstream end of the barrel 20. The raw material supply unit 30 includes a plurality of feeders 31 and a hopper 32, and each of the plurality of feeders 31 supplies each raw material into the barrel 20 from the hopper 32 through the raw material supply port 20a with a set supply amount. It is configured.

  A rotation drive unit 40 is provided on the upstream side of the barrel 20, and one end of a pair of screws 10 is coupled to the rotation drive unit 40. The rotational drive unit 40 includes a drive motor and a gear box, and the screw 10 is rotationally driven by them at a set rotational speed, and a mixture (hereinafter referred to as “resin”) containing polylactic acid resin and surface-treated inorganic powder. The mixture M ′ ”) is kneaded.

  A die 22 is provided at the downstream end of the barrel 20. The die 22 has a heater so that a melt-kneaded product (hereinafter referred to as “kneaded product M”) of the resin mixture M ′ is extruded from the discharge port into a predetermined shape such as a string or a sheet at a set temperature. It is configured.

  On the downstream side of the barrel 20, a cooling tank 50 and a pelletizing unit 60 are sequentially provided. Cooling water W is stored in the cooling tank 50, and the kneaded material M pushed out from the die 22 is immersed in the cooling water W to be cooled. In addition, the cooling means of the kneaded material M is not limited to water cooling, Air cooling may be sufficient. The pelletizing unit 60 is configured to pelletize the kneaded material M cooled in the cooling tank 50 into a pellet form or the like.

  The barrel 20 may be provided with a deaeration mechanism or a side feeder.

  2 and 3 show the inside of the barrel 20 through which the pair of screws 10 are inserted.

Each screw 10 is configured by connecting a plurality of screw elements 111 and 112 along the length direction of the rotary shaft 12. The outer diameter D of each screw 10 is 30 mm or more, and preferably 35 mm or more. In each screw 10, a portion where the screw elements 111 and 112 are continuously provided along the length direction constitutes a screw effective portion, and the length, that is, the sum of the lengths of the screw elements 111 and 112 is the screw. the effective length L _e. The ratio of the length L ₁ of the downstream portion from the position corresponding to the center to the outer diameter D of the screw 10 with respect to the center of the raw material supply port 20a of the barrel 20 outside the screw 10 in the screw effective portion (reference) L ₁ / D) is 30 or more in order to sufficiently knead the resin mixture M ′. Moreover, it is preferable that it is 60 or less from a viewpoint of preventing deterioration by heat_generation | fever etc. of resin mixture M '. The ratio (L ₂ / D) of the length L ₂ of the screw elements 111 and 112 to the outer diameter D of the screw 10 is preferably, for example, 0.1 to 3.0, and preferably 0.5 to 2.0. Is more preferable.

  The plurality of screw elements 111 and 112 include a conveying element 111 and a kneading element 112. Each of the pair of screws 10 is configured such that the conveying element 111 or the kneading element 112 can be arranged at an arbitrary position along the length direction thereof, and is conveyed to a portion where the conveying element 111 is provided. The kneading part is constituted in the part where the kneading element 112 is provided.

  As shown in FIG. 2, the transport element 111 has a structure in which a strip-shaped screw blade is coupled to the rotary shaft 12 side and provided in a spiral shape. The ratio (P / D) of the helical pitch P of the screw blades to the outer diameter D of the screw 10 is, for example, 0.1 to 2.0. The plurality of transport elements 111 provided in each screw 10 may have a uniform spiral pitch P, or may have different spiral pitch P. The conveying speed of the resin mixture M ′ can be controlled by the size of the helical pitch P.

  The kneading element 112 is configured to give higher shear to the resin mixture M ′ than the conveying element 111. Examples of the kneading element 112 include a forward kneading disk, a reverse kneading disk, a forward rotor, a reverse rotor, a pineapple, a neutral, a wide, and the like as disclosed in JP-A-10-272624.

  The pair of screws 10 are arranged in parallel in the horizontal direction, but when they rotate in the same direction, they do not have an interference part in a plan view, but in a front view, one rotation locus and the other The rotation trajectory has an overlapping portion, thereby forming a meshing structure. The pair of screws 10 are usually provided with the same type of screw elements 111 and 112 at the same position in the length direction, but when they are rotated in the same direction, they do not have an interference portion in plan view. Different types of screw elements 111 and 112 may be provided at the same position in the length direction.

The barrel 20 is configured by connecting a plurality of cylindrical barrel units 21, and a screw insertion hole 23 having a transverse cross-sectional outer shape that is a contour shape formed by a pair of circles intersecting each other in the length direction. It is formed to extend. The number of barrel units 21 provided is, for example, 7 to 20. The ratio (L ₃ / D) of the length L ₃ of each barrel unit 21 to the outer diameter D of the screw 10 is, for example, 3 to 5.

  Each barrel unit 21 is provided with a heater. Therefore, the barrel 20 is divided into a plurality of portions of the barrel unit 21 unit, and the temperature can be set independently of each other along the length direction in the divided unit. Each barrel unit 21 is provided with a cooling means (not shown) for temperature control.

  In the same-direction meshing twin-screw extruder 100 according to the present embodiment, the heaters of each unit, the drive motor of the rotation drive unit 40, and the like are connected to a control unit (not shown).

  Examples of commercially available same-direction meshing twin screw extruders include the TEM series manufactured by Toshiba Machine, the TEX series manufactured by Nippon Steel, the ZSK type manufactured by Warner, and the PCM series manufactured by Ikekai Tekko. It is done.

(Production method of polylactic acid resin composition)
A method for producing a polylactic acid resin composition using the same-direction meshing twin-screw extruder 100 according to this embodiment will be described.

<Raw material>
The raw material used in the method for producing the polylactic acid resin composition according to this embodiment includes a polylactic acid resin and a surface-treated inorganic powder.

-Polylactic acid resin-
As a polylactic acid resin used as a raw material, polylactic acid obtained by condensation polymerization of only a lactic acid component as a monomer, and a lactic acid component and a hydroxycarboxylic acid component other than lactic acid (hereinafter referred to as “hydroxycarboxylic acid component”) as a monomer are subjected to condensation polymerization. And polylactic acid as a copolymer. The polylactic acid resin may be configured to include any one of these, or may be configured to include both. The polylactic acid resin is preferably a biodegradable resin that is decomposed into a low molecular weight compound by microorganisms in nature. In the present specification, “biodegradable” means a property that can be decomposed into a low molecular weight compound by a microorganism in nature. Specifically, JIS K6953 (ISO 14855) “controlled aerobic composting conditions”. This means biodegradability based on the “Aerobic and Ultimate Biodegradation and Disintegration Test”.

  The lactic acid component includes optical isomers of L-lactic acid (L form) and D-lactic acid (D form). The polylactic acid resin used as a raw material may include only one of the optical isomers as the lactic acid component, or may include both. From the viewpoint of improving the flexibility, heat resistance, and moldability of the polylactic acid resin composition to be produced, a polylactic acid resin containing a lactic acid component having a high optical purity mainly composed of any optical isomer is preferred. In the present specification, the “main component” refers to a component whose content in the lactic acid component is 50 mol% or more.

  Examples of the hydroxycarboxylic acid component include hydroxycarboxylic acid compounds such as glycolic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxypentanoic acid, and hydroxycaproic acid. Of these, glycolic acid and hydroxycaproic acid are preferred from the viewpoint of enhancing the flexibility, heat resistance, and transparency of the polylactic acid resin composition to be produced. The hydroxycarboxylic acid component may be composed of a single species or a plurality of species.

  The lactic acid component and the hydroxycarboxylic acid component may contain a dimer of lactic acid or a hydroxycarboxylic acid compound. Preferable examples include D-lactide and L-lactide which increase the heat resistance and transparency of the polylactic acid resin composition to be produced. In addition, the dimer of lactic acid may be contained in any lactic acid component of polylactic acid obtained by condensation polymerization of only a lactic acid component and polylactic acid obtained by condensation polymerization of a lactic acid component and a hydroxycarboxylic acid component.

  The content of the dimer of lactic acid in the lactic acid component is preferably 80 to 100 mol% from the viewpoint of increasing the flexibility and heat resistance of the polylactic acid resin composition to be produced, and is 90 to 100 mol%. More preferably.

  The content of the dimer of the hydroxycarboxylic acid compound in the hydroxycarboxylic acid component is preferably 80 to 100 mol% from the viewpoint of enhancing the flexibility and heat resistance of the polylactic acid resin composition to be produced, 90 More preferably, it is -100 mol%.

  The method for polycondensing only the lactic acid component and the method for polycondensing the lactic acid component and the hydroxycarboxylic acid component are not particularly limited, and known methods can be applied.

  If the monomer to be polycondensed is selected, for example, polylactic acid having an L-lactic acid component or a D-lactic acid component of 85 mol% or more and less than 100 mol% and a hydroxycarboxylic acid component of more than 0 mol% and 15 mol% or less is obtained Can do. The polylactic acid resin used as a raw material is preferably polylactic acid obtained by using lactide, which is a cyclic dimer of lactic acid, glycolide, which is a cyclic dimer of glycolic acid, and caprolactone as monomers. The optical purity of polylactic acid is preferably 95% or more, more preferably 98% or more, from the viewpoint of enhancing the flexibility and heat resistance of the polylactic acid resin composition to be produced. The optical purity of polylactic acid is determined by the D-body content measurement method described in “Voluntary Standard for Food Containers and Packaging Made of Synthetic Resins such as Polyolefins, Third Edition, Revised June 2004, Part 3 Sanitation Test Method P12-13”. Can be based on.

  The polylactic acid resin is a stereocomplex polythene composed of two types of polylactic acid obtained by using lactic acid components mainly composed of different isomers from the viewpoint of enhancing the flexibility and heat resistance of the polylactic acid resin composition to be produced. It may be composed of lactic acid.

  One polylactic acid (hereinafter referred to as “polylactic acid A”) contained in the stereocomplex polylactic acid is composed of 90 to 100 mol% of the L-lactic acid component and 0 to 10 mol% of the other components including the D-lactic acid component. The other polylactic acid (hereinafter referred to as “polylactic acid B”) is composed of 90 to 100 mol% of D-lactic acid component and 0 to 10 mol% of other components including L-lactic acid component. The stereocomplex polylactic acid preferably has a weight ratio of polylactic acid A to polylactic acid B (polylactic acid A / polylactic acid B) of 10/90 to 90/10, preferably 20/80/80/20. Is more preferable, and 40/60 to 60/40 is even more preferable. In addition, as other components other than the L-lactic acid component and the D-lactic acid component, for example, dicarboxylic acid, polyhydric alcohol, hydroxycarboxylic acid, lactone, etc. having two or more functional groups capable of forming an ester bond in the molecule. And polyesters, polyethers, polycarbonates, etc. having two or more unreacted functional groups in the molecule.

  The melting point (Tm) of the polylactic acid resin increases the dispersibility of internal additives such as plasticizers and crystal nucleating agents, increases the bending strength of the polylactic acid resin composition to be produced, suppresses deterioration, and productivity. From the viewpoint of increasing the temperature, it is preferably 140 to 250 ° C, more preferably 150 to 240 ° C, and further preferably 160 to 230 ° C. In addition, melting | fusing point of polylactic acid resin can be measured from the crystal melting endothermic peak temperature by the temperature rising method of differential scanning calorimetry (DSC) based on JIS-K7121.

  The polylactic acid resin used as a raw material can be obtained by condensation polymerization of a monomer, and can also be obtained as a commercial product. Examples of such commercially available products include “Lacia series” such as Lacia H-100, H-280, H-400, and H-440 manufactured by Mitsui Chemicals; 3001D, 3051D, 4032D, 4042D, and 6201D manufactured by Nature Works. "Nature Works" such as 6251D, 7000D, 7032D, etc .; "Ecoplastic U'z series" such as Eco Plastic U'z S-09, S-12, S-17 manufactured by Toyota Motor Corporation, etc. Is preferable from the viewpoint of enhancing the flexibility and heat resistance of the polylactic acid resin composition to be produced.

-Inorganic powder with surface treatment-
Examples of inorganic powders include metal hydroxides, metal hydrates, and layered silicates. A single kind of inorganic powder may be blended, or a plurality of kinds may be blended.

  Examples of the metal hydroxide or metal hydrate include aluminum hydroxide, magnesium hydroxide, calcium hydroxide, calcium aluminate hydrate, tin oxide hydrate, progobite, zinc nitrate hexahydrate, Examples thereof include nickel nitrate hexahydrate. Of these, aluminum hydroxide and magnesium hydroxide are preferred from the viewpoint of reducing the cost of the polylactic acid resin composition to be produced and improving flame retardancy.

  Examples of the layered silicate include talc, smectite, kaolin, mica, montmorillonite, etc. Among these, talc and mica are preferable from the viewpoint of increasing the heat resistance of the polylactic acid resin composition to be produced.

  Examples of the surface treatment applied to the inorganic powder include a surface treatment using a silane coupling agent, a higher fatty acid, a titanate coupling agent, a sol-gel coating agent, a silicone polymer coating agent, a resin coating agent, nitrate, and the like. It is done. From the viewpoint of increasing the flexibility and heat resistance of the polylactic acid resin composition to be produced, surface treatment with a silane coupling agent is preferred among these.

  Examples of the silane coupling agent include coupling agents such as isocyanate silane, amino silane, mercapto silane, epoxy silane, vinyl silane, methacryl silane, and epoxy silane. Among these, from the viewpoint of enhancing the flexibility and heat resistance of the polylactic acid resin composition to be produced, a coupling agent of isocyanate silane, aminosilane, mercaptosilane, or epoxysilane is preferable, and isocyanate silane is more preferable.

  Examples of the isocyanate silane include 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, tris- (3-trimethoxysilylpropyl) isocyanurate, and the like.

  Examples of the aminosilane include γ-aminopropyltriethoxysilane, n-β (aminoethyl) γ-aminopropyltriethoxysilane, γ-ureidopropyltriethoxysilane, and the like.

  Examples of mercaptosilane include 3-mercaptopropyltrimethoxysilane.

  Examples of the epoxy silane include 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, and 3-glycidoxypropylmethyldiethoxysilane.

  The inorganic powder subjected to the surface treatment with the silane coupling agent is, for example, sprayed or coated on the surface of the inorganic powder with a solution obtained by dissolving the silane coupling agent in a solvent such as acetone, ethyl acetate or toluene. Then, it can obtain by the method of drying and removing a solvent.

  From the viewpoint of improving the flexibility and heat resistance of the polylactic acid resin composition to be produced, the inorganic powder subjected to the surface treatment with the silane coupling agent has a weight ratio between the silane coupling agent and the inorganic powder (silane coupling). Agent / inorganic powder) is preferably processed at a ratio of 0.1 / 99.9 to 5/95, more preferably 0.3 / 99.7 to 3/97. What was processed as a ratio of 5 / 99.5-2/98 is further more preferable.

  The surface-treated inorganic powder is preferably a granule having an average particle size of 10 μm or less, and more preferably a granule having an average particle size of 0.1 to 5 μm. This average particle diameter can be obtained from the volume-based median diameter by a diffraction / scattering method.

  The blending amount of the surface-treated inorganic powder with respect to 100 parts by weight of the polylactic acid resin is 50 to 200 parts by weight from the viewpoint of enhancing the flexibility and heat resistance of the polylactic acid resin composition to be produced, and 60 to 150 parts by weight. It is preferable that

-Plasticizer-
The raw material used in the method for producing the polylactic acid resin composition according to this embodiment may further contain a plasticizer.

  Examples of the plasticizer include polybasic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, 1,3,6-hexanetricarboxylic acid, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, triethylene glycol monomethyl ether, Esters with polyethylene glycol monoalkyl ethers such as triethylene glycol monoethyl ether and tetraethylene glycol monomethyl ether; polyhydric alcohols such as glycerin, ethylene glycol, diglycerin and 1,4-butanediol, ethylene oxide and / or propylene Oxidized acetylated products; hydroxybenzoic acid esters such as 2-ethylhexyl hydroxybenzoate; di-2-ethylhexyl phthalate, etc. Phthalic acid esters; Adipic acid esters such as adipic acid diester and dioctyl adipate; Maleic acid esters such as di-n-butyl maleate; Succinic acid esters such as methyltriglycol succinic acid diester; Citric acid such as tributyl acetylcitrate Esters; alkyl phosphate esters such as tricresyl phosphate; tricarboxylic acid esters such as trioctyl trimellitic acid; acetylated polyoxyethylene alkyl (alkyl group having 2 to 15 carbon atoms) ether such as acetylated polyoxyethylene hexyl ether Can be mentioned.

  From the viewpoint of enhancing the flexibility and heat resistance of the polylactic acid resin composition to be produced, the plasticizer is adipic acid ester such as adipic acid diester, succinic acid ester such as methyltriglycol succinic acid diester, 1,3,6- Esters of hexanetricarboxylic acid and polyethylene glycol (average addition mole number of ethylene oxide 0.5 to 5) monomethyl ether, acetic acid and glycerin or ethylene glycol ethylene oxide adduct (average addition mole number of ethylene oxide 3 to 20) The esters are preferred.

  As the plasticizer, a carboxylic acid ester can also be suitably used. The carboxylic acid ester includes (1) a monohydric alcohol having an alkyl group having 1 to 4 carbon atoms, (2) a dicarboxylic acid having an alkylene group having 2 to 4 carbon atoms, and (3) 2 carbon atoms. It is preferably obtained from a dihydric alcohol having 6 to 6 alkylene groups, having an acid value of 1 mg KOH / g or less, a hydroxyl value of 5 mg KOH / g or less, and a number average molecular weight of 300 to 700.

  Moreover, phosphate ester can also be used suitably. As such a phosphate ester, a polyether-type phosphate triester is preferable. The polyether-type phosphoric acid triester may have a target structure or may have an asymmetric structure.

  A single kind of plasticizer may be blended, or a plurality of kinds may be blended. The blending amount of the plasticizer with respect to 100 parts by weight of the polylactic acid resin is preferably 3 to 50 parts by weight and more preferably 3 to 30% by weight from the viewpoint of increasing the flexibility of the polylactic acid resin composition. 3 to 20% by weight is more preferable.

-Crystal nucleating agent-
The raw material used in the method for producing the polylactic acid resin composition according to this embodiment may further contain a crystal nucleating agent.

  Examples of the crystal nucleating agent include fatty acid monoamides, fatty acid bisamides, aromatic carboxylic acid amides, rosinic acid amides, and the like; hydroxy fatty acid esters; aromatic sulfonic acid dialkyl ester metal salts, phenylphosphonic acid metal salts, phosphorus Metal salts such as acid ester metal salts and rosin acid metal salts; carbohydrazides, N-substituted ureas, organic pigments and the like.

  From the viewpoint of enhancing the flexibility and heat resistance of the polylactic acid resin composition to be produced, the crystal nucleating agent has a single compound having a hydroxyl group and an amide group in the molecule, or has a hydroxyl group and an amide group in the molecule. A combination of the compound and a metal salt of phenylphosphonic acid is preferred.

  Examples of the compound having a hydroxyl group and an amide group in the molecule include hydroxy fatty acid monoamides such as 12-hydroxystearic acid monoethanolami; methylene bis 12-hydroxystearic acid amide, ethylene bis 12-hydroxystearic acid amide, hexamethylene bis And hydroxy fatty acid bisamides such as 12-hydroxystearic acid amide. From the viewpoint of improving flexibility, heat resistance, impact resistance, bloom resistance, and moldability of the polylactic acid resin composition to be produced, methylene bis 12-hydroxy stearamide, ethylene bis 12-hydroxy stearamide, hexa Alkylene bishydroxystearic acid amides such as methylene bis 12-hydroxystearic acid amide are preferred, and ethylene bis 12-hydroxystearic acid amide is more preferred.

The phenylphosphonic acid metal salt is a metal salt of phenylphosphonic acid having a phenyl group which may have a substituent and a phosphonic group (—PO (OH) ₂ ). Examples thereof include an alkyl group having 1 to 10 alkyl groups and an alkoxycarbonyl group having 1 to 10 carbon atoms in the alkoxy group.

  Examples of the phenylphosphonic acid include unsubstituted phenylphosphonic acid, methylphenylphosphonic acid, ethylphenylphosphonic acid, propylphenylphosphonic acid, butylphenylphosphonic acid, dimethoxycarbonylphenylphosphonic acid, diethoxycarbonylphenylphosphonic acid, and the like. Of these, unsubstituted phenylphosphonic acid is preferred.

  Examples of the metal constituting the phenylphosphonic acid metal salt include lithium, sodium, magnesium, aluminum, potassium, calcium, barium, copper, zinc, iron, cobalt, nickel, and the like. Among these, zinc is preferable.

  In the case where a compound having a hydroxyl group and an amide group in the molecule and a phenylphosphonic acid metal salt are used in combination, the proportion thereof is increased in the molecule from the viewpoint of increasing the flexibility and heat resistance of the polylactic acid resin composition to be produced. The weight ratio of the compound having a hydroxyl group and an amide group to the phenylphosphonic acid metal salt (weight ratio of the compound having a hydroxyl group and an amide group in the molecule / the phenylphosphonic acid metal salt) is from 20/80 to 80/20. Is preferable, 30/70 to 70/30 is more preferable, and 40/60 to 60/40 is even more preferable.

  A single kind of crystal nucleating agent may be blended, or a plurality of kinds may be blended. The blending amount of the crystal nucleating agent with respect to 100 parts by weight of the polylactic acid resin is preferably 0.05 to 10 parts by weight from the viewpoint of enhancing the flexibility and heat resistance of the polylactic acid resin composition to be produced. More preferably, it is -8 weight part, and it is further more preferable that it is 0.05-5 weight part.

-Hydrolysis inhibitor-
The raw material used in the method for producing the polylactic acid resin composition according to this embodiment may further contain a hydrolysis inhibitor.

  The hydrolysis inhibitor is not particularly limited, and examples thereof include those described in paragraphs 0042 to 0044 of JP2009-270087A. The hydrolysis inhibitor is preferably a polycarbodiimide compound from the viewpoint of enhancing the moldability of the polylactic acid resin composition to be produced. From the viewpoint of increasing the flexibility, heat resistance, impact resistance of the polylactic acid resin composition to be produced, and the bloom resistance of the organic crystal nucleating agent, a monocarbodiimide compound is preferred. From the viewpoint of enhancing the durability of the polylactic acid resin composition to be produced, a combination of a monocarbodiimide compound and a polycarbodiimide compound is preferable.

  As the hydrolysis inhibitor, a single species may be blended or a plurality of species may be blended. The blending amount of the hydrolysis inhibitor with respect to 100 parts by weight of the polylactic acid resin is 0.05 to 10 parts by weight from the viewpoint of enhancing the flexibility, heat resistance, and durability of the polylactic acid resin composition to be produced. preferable.

-Other ingredients-
In addition, the raw materials used in the method for producing the polylactic acid resin composition according to this embodiment include hindered phenols, phosphite antioxidants, hydrocarbon waxes, and anionic surfactant lubricants. Also good. The compounding quantity with respect to 100 weight part of polylactic acid resin of antioxidant is 0.05-3 weight part, for example. The compounding quantity with respect to 100 weight part of polylactic acid resin of a lubricant is 0.1-2 weight part, for example.

  The raw material used in the method for producing the polylactic acid resin composition according to the present embodiment is a range that does not deteriorate the flexibility and heat resistance of the polylactic acid resin composition to be produced, and further includes a flame retardant, an antistatic agent, an antifogging agent, It may contain a light stabilizer, an ultraviolet absorber, a pigment, an antifungal agent, an antibacterial agent, a foaming agent, an antidrip agent and the like.

  Among the additives, the flame retardant is preferably a phosphorus-based flame retardant from the viewpoint of improving the flame retardancy, flexibility, and heat resistance of the polylactic acid resin composition to be produced. Examples of the phosphorus-based flame retardant that improves the flame retardancy of the polylactic acid resin composition include phosphate esters, condensed phosphate esters, phosphates, and condensed phosphates. A single type of phosphorus-based flame retardant may be blended, or a plurality of types may be blended.

  Examples of phosphate esters include trimethyl phosphate, triethyl phosphate, tributyl phosphate, tri (2-ethylhexyl) phosphate, tributoxyethyl phosphate, triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, tris (isopropylphenyl) phosphate. , Tris (phenylphenyl) phosphate, trinaphthyl phosphate, cresyl diphenyl phosphate, xylenyl diphenyl phosphate, diphenyl (2-ethylhexyl) phosphate, di (isopropylphenyl) phenyl phosphate, monoisodecyl phosphate, 2-acryloyloxyethyl acid Phosphate, 2-methacryloyloxyethyl acid phosphate, diphenyl 2-acryloyloxyethyl phosphate, diphenyl-2-methacryloyloxyethyl phosphate, melamine phosphate, dimelamine phosphate, melamine pyrophosphate, triphenylphosphine oxide, tricresylphosphine oxide, diphenyl methanephosphonate, diethyl phenylphosphonate, relucinol Examples thereof include bis (diphenyl phosphate), bisphenol A bis (diphenyl phosphate), phosphaphenanthrene, and among these, triphenyl phosphate, tris (isopropylphenyl) phosphate, and cresyl diphenyl phosphate are preferable.

  Examples of the condensed phosphate ester include trialkyl polyphosphate, resorcinol polyphenyl phosphate, resorcinol poly (di-2,6-xylyl) phosphate, bisphenol A polycresyl phosphate, hydroquinone poly (2,6-xylyl) phosphate, and Examples thereof include condensed phosphate esters such as these condensates. Examples of commercially available condensed phosphate esters include PX-200, PX-201, PX-202, CR-733S, CR-741, CR747 manufactured by Daihachi Chemical Co., Ltd., Adeka Stab PFR, FP-500, and FP- manufactured by ADEKA. 600, FP-700, and the like. Among these, PX-200, PX-201, and PX-202 are preferable.

  Examples of phosphates and condensed phosphates include phosphates and polyphosphates composed of salts of phosphoric acid, polyphosphoric acid and metals in groups 1 to 14 of the periodic table, ammonia, aliphatic amines, and aromatic amines. Etc. Representative salts of polyphosphates include, for example, lithium salts that are metal salts, sodium salts, calcium salts, barium salts, iron (II) salts, iron (III) salts, aluminum salts, etc .; aliphatic amine salts Certain methylamine salts, ethylamine salts, diethylamine salts, triethylamine salts, ethylenediamine salts, piperazine salts and the like; pyridine salts, triazine salts, melamine salts, ammonium salts and the like which are aromatic amine salts. Examples of commercially available phosphates and polyphosphates include Taiyen N, Taien L, Taien E, Taien S, Taien H, Clariant Clariant AP475, Clariant AP475, Clariant AP750, Clariant 1312, Clariant 1250, and ADEKA. FP-2100, FP-2100J, FP-2200, Suzuhiro Chemical Co., Ltd. FC730, Budenheimu BUDIT 3167, Nippon Chemical Industry Co., Ltd. N-6ME, Nissan Chemical Co., Ltd. PHOSMEL-200, etc. Among these, ADEKA FP-2100, FP-2100J, and FP-2200 manufactured by Nissan Chemical Industries, and PHOSMEL-200 manufactured by Nissan Chemical Co., Ltd. are preferable.

  Furthermore, examples of the anti-drip agent include thermosetting resins such as fluorine resins and phenol resins. Examples of the fluororesin include, for example, a homopolymer or copolymer of a fluorine-containing monomer such as tetrafluoroethylene, chlorotrifluoroethylene, vinylidene fluoride, hexafluoropropylene, perfluoroalkyl vinyl ether; the fluorine-containing monomer, ethylene, propylene, Examples thereof include a copolymer with a copolymerizable monomer such as (meth) acrylate. A single type of anti-drip agent may be blended, or a plurality of types may be blended.

<Kneading>
In the method for producing a polylactic acid resin composition according to the present embodiment, raw materials are charged into the same-direction meshing twin screw extruder 100 and kneaded under the following conditions 1 to 3. According to the method for producing a polylactic acid resin composition according to the present embodiment, when a mixture containing a polylactic acid resin and a surface-treated inorganic powder is kneaded using a co-directional meshing twin screw extruder, Obtaining excellent flexibility and heat resistance in the manufactured polylactic acid resin composition by providing the specific first and specific second temperature setting zones and the first and second kneading parts as follows. Can do.

-Condition 1-
As condition 1, a first temperature setting zone is provided in the barrel 20 so as to include a range of at least 6.3D to 13Dmm from the center position of the raw material supply port 20a of the barrel 20. Hereinafter, the position display (D display) in the barrel 20 using D means the distance from the center position of the raw material supply port 20a of the barrel 20.

  In the first temperature setting zone, the set temperature of the barrel unit 21 is set to (Tm + 50) to (Tm + 80) ° C., where the melting point of the polylactic acid resin is Tm. The set temperature of the barrel unit 21 is preferably 210 to 240 ° C, and more preferably 210 to 230 ° C, from the viewpoint of enhancing the flexibility and heat resistance of the polylactic acid resin composition to be produced. In the first temperature setting zone, an internal additive containing inorganic powder subjected to surface treatment is kneaded with polylactic acid resin in a molten state in a barrel 20 set at (Tm + 50) to (Tm + 80) ° C. To form a resin mixture M ′.

  The starting point of the first temperature setting zone is not particularly limited as long as the first temperature setting zone includes at least the range of 6.3D to 13Dmm.

  In the first temperature setting zone, the conveying element 111 of the screw elements 111 and 112 is provided in a corresponding portion of the screw 10, and therefore the resin mixture M ′ is conveyed and kneaded by the conveying element 111.

  In addition, as condition 1, a second temperature setting zone is provided in the barrel 20 so as to include at least a range after 19.3 Dmm from the center position of the raw material supply port 20a of the barrel 20 on the downstream side of the first temperature setting zone. .

  In the second temperature setting zone, the set temperature of the barrel unit 21 is set to (Tm−20) to (Tm + 40) ° C., preferably (Tm) to (Tm + 30) ° C. The set temperature of the barrel unit 21 is preferably 140 to 200 ° C, and more preferably 160 to 190 ° C, from the viewpoint of enhancing the flexibility and heat resistance of the polylactic acid resin composition to be produced.

  The starting point of the second temperature setting zone is downstream from the first temperature setting zone, and is not particularly limited as long as the second temperature setting zone includes a range of at least 19.3 Dmm.

  In the second temperature setting zone, the conveying element 111 of the screw elements 111 and 112 may be provided in a corresponding part of the screw 10, and the conveying and mixing of the resin mixture M ′ may be performed by the conveying element 111. And the resin mixture M ′ may be kneaded by the kneading element 112. Note that, as described below, the second kneading part under the condition 3 is included in the second temperature setting zone.

-Condition 2-
As condition 2, a first kneading section having a length of 1D to 4Dmm is provided so as to have a start point and an end point within a range of 13D to 20.9Dmm from the center position of the raw material supply port 20a of the barrel 20.

  The starting point of the first kneading part is not particularly limited as long as the first kneading part has a starting point and an ending point in the range of 13D to 20.9 Dmm, but the flexibility of the polylactic acid resin composition to be manufactured and From the viewpoint of enhancing the heat resistance, it is preferable to position it within 7 Dmm from the end point of the first temperature setting zone, and it is more preferable to position it so as to coincide with the end point of the first temperature setting zone.

  In the first kneading section, the kneading element 112 of the screw elements 111 and 112 is provided in a corresponding portion of the screw 10, and accordingly, the resin mixture M ′ is kneaded by the kneading element 112.

  The set temperature of the barrel unit 21 in the first kneading part is not particularly limited, but from the viewpoint of improving the flexibility and heat resistance of the polylactic acid resin composition to be produced, (Tm-20) to (Tm + 80) Preferably, the temperature is set to (Tm-10) to (Tm + 70) ° C, more preferably 140 to 240 ° C, and even more preferably 150 to 230 ° C.

-Condition 3-
As condition 3, a second kneading section having a length of 1D to 4Dmm is provided so as to have a starting point in a range after 20.9 DDmm from the center position of the raw material supply port 20a of the barrel 20.

  The starting point of the second kneading part is not particularly limited as long as it is within the range of 20.9 Dmm or more, but from the viewpoint of increasing the flexibility and heat resistance of the polylactic acid resin composition to be produced, the first temperature It is preferably positioned within 15 Dmm from the end point of the set zone, more preferably within 10 Dmm, and even more preferably within 3 Dmm. Further, the start point of the second kneading unit may be positioned so as to coincide with the end point of the first kneading unit, and the first and second kneading units may be configured to be continuous.

  In the second kneading section, the kneading element 112 of the screw elements 111 and 112 is provided in a corresponding portion of the screw 10, and accordingly, the resin mixture M ′ is kneaded by the kneading element 112.

  Since the second kneading part is included in the second temperature setting zone as described above, the set temperature of the barrel unit 21 is (Tm−20) to (Tm + 40) ° C., but the polylactic acid resin composition to be manufactured is acceptable. From the viewpoint of improving flexibility and heat resistance, the set temperature of the barrel unit 21 in the second kneading part is preferably (Tm) to (Tm + 0) ° C, preferably 140 to 200 ° C, and 160 to 190. More preferably, the temperature is set to ° C.

-Other conditions-
A conveyance unit in which the conveyance element 111 is mounted on the screw 10 may be provided on the upstream side of the first temperature setting zone in the barrel 20. The conveying unit has a length of, for example, 3.0D to 4.2Dmm, and a set temperature of the barrel unit 21 is, for example, (Tm−150) to (Tm + 80) ° C. It is preferable that this conveyance part contains the range of 0-5.0Dmm.

  As described above, the first temperature setting zone and the first kneading unit may be provided continuously, or a conveyance unit in which the conveyance element 111 is mounted on the screw 10 may be provided therebetween.

Further, as the kneading conditions, the discharge amount Q per hour (kg / hour), that is, the raw material supply amount is appropriately set according to the scale of the same-direction meshing twin screw extruder 100,
Q is preferably in the range of 0.005D ^{2.5 to} 0.03D ^2.5 . The rotation speed N of the screw 10 is appropriately set according to the scale of the same-direction meshing twin-screw extruder 100, and is, for example, 10 to 1500 rpm. The ratio Q / N between the discharge amount Q (kg / hour) and the screw rotation speed N (rpm) is such that the dispersibility of the internal additive including the inorganic powder subjected to the surface treatment is good, and the polylactic acid to be produced From the viewpoint of increasing the flexibility and heat resistance of the resin composition, it is preferable to have a relationship of 0.2 ≦ Q / N ≦ 1.5, and a relationship of 0.2 ≦ Q / N ≦ 1.0. Is more preferable.

<Cooling>
In the method for producing the polylactic acid resin composition according to the present embodiment, the kneaded product M of the polylactic acid resin composition extruded from the barrel 20 through the die 22 is continuously connected to the cooling water W stored in the cooling tank 50. Immerse and solidify by cooling. The temperature of the cooling water W shall be 10-40 degreeC, for example.

<Pelletize>
In the method for producing a polylactic acid resin composition according to the present embodiment, the kneaded product M of the polylactic acid resin composition pulled up from the cooling bath 50 is put into the pelletizing unit 60 and pelletized into pellets or chips. The particle size of the pellet-shaped or chip-shaped polylactic acid resin composition is, for example, 2 to 5 mm.

  From the viewpoints of pelletizing property to pellets in the pelletizing part 60, drying of the pellets, and prevention of blocking between pellets at the time of inventory, the polylactic acid resin of the kneaded product M is preferably crystallized in the pelletizing part 60, From the viewpoint of promoting crystallization, the surface temperature of the kneaded material M from the cooling bath 50 to the pelletizing portion 60 is preferably maintained at 70 to 120 ° C. From the viewpoint of keeping the surface temperature of the kneaded material M within the above range, the cooling tank 50 may be composed of at least one tank or two or more tanks, and the water temperature is preferably in the range of 10 to 90 ° C. You may use it at a different temperature when comprising with a tank.

  The pellet-like or chip-like polylactic acid resin composition produced as described above is used for a molding material such as injection molding.

(Production of polylactic acid resin composition)
The following polylactic acid resin compositions of Examples 1 to 25 and Comparative Examples 1 to 7 were produced. Each content is also shown in Tables 1-5.

<Example 1>
A pellet-like polylactic acid resin composition was produced using the same-direction meshing twin-screw extruder (TEM-41SS manufactured by Toshiba Machine Co., Ltd.) having the same configuration as that of the above-described embodiment.

Each screw has an outer diameter D of 41mm and a screw effective length L _e (total length = barrel length of the effective screw portion screw elements are provided) was used as the 45.65Dmm. Each screw has a kneading element from the upstream side to the kneading element in the order of a length of 82 mm (2 Dmm) starting from a position of 611 mm (14.9 Dmm) from the position corresponding to the center of the barrel material supply port Then, neutral and reverse kneading were attached in order (first kneading part). In addition, the kneading element from the upstream side, which is a kneading element, is also kneaded, neutral, in a portion starting at a position of 857 mm (20.9 Dmm) from the position corresponding to the center of the raw material supply port of the barrel. Were attached in order (second kneading section). In addition, the conveyance element was provided in the other part of each screw.

The barrel was constituted by connecting 11 barrel units (L ₃ /D=4.15) continuously. The barrel had a raw material supply port in the first unit, and the central position of the raw material supply port was 2.07 Dmm from the upstream end of the first unit. With reference to the center position of this raw material supply port, the position of each unit in the barrel length direction is 0 to 2.08 Dmm for the first unit, 2.08 D to 6.23 Dmm for the second unit, 6.23D-10.38Dmm, 4th unit 10.38D-14.53Dmm, 5th unit 14.53D-18.68Dmm, 6th unit 18.68D-22.83Dmm, 7th unit 22. 83D ~ 26.98Dmm, 8th unit is 26.98D ~ 31.13Dmm, 9th unit is 31.13D ~ 35.28Dmm, 10th unit is 35.28D ~ 39.43D, and 11th unit is 39.43D ˜43.58 Dmm. Further, the ratio (L ₁ / D) of the length L ₁ of the downstream portion from the position corresponding to the center of the barrel raw material supply port in the effective screw portion to the outer diameter D of the screw is 43.58.

  The set temperature of the barrel unit is, in order from the upstream side, the first to second units (A temperature zone: 0 to 6.23 Dmm (zone length: 6.23 Dmm)) at 50 ° C., the third to fourth units (B Temperature zone: 6.23D-14.53Dmm (zone length: 8.30Dmm)) 220 ° C., and 5th unit (C temperature zone: 14.53D-18.68Dmm (zone length: 4.15Dmm)) The sixth to eleventh units (D temperature zone: 18.68D to 43.58 Dmm (zone length: 24.90 Dmm)) were set to 180 ° C.

  The raw material is an isocyanate-based silane cup based on 99% by weight of polylactic acid resin (manufactured by Nature Works, product number: 4032D, melting point (Tm): 160 ° C.) and aluminum hydroxide (trade name: B703, manufactured by Nippon Light Metal Co., Ltd.). Aluminum hydroxide 1 having a surface treatment of 1% by weight of a ring agent (3-isocyanatopropyltriethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBE-9007) was used. The formulation was 100 parts by weight of aluminum hydroxide 1 with respect to 100 parts by weight of the polylactic acid resin. In addition, melting | fusing point (Tm) was measured from the crystal melting endothermic peak temperature by the temperature rising method of differential scanning calorimetry (DSC) based on JISK7121.

  The kneading conditions were a discharge amount Q of 120 kg / hour and a screw rotation speed N of 265 rpm. Therefore, Q / N is 0.453.

  Here, in the manufacture of Example 1, since the raw material was constituted by blending the polylactic acid resin and the surface-treated aluminum hydroxide 1 with the latter 100 parts by weight with respect to the former 100 parts by weight, the raw material structure of the present invention Meet the condition.

  The B temperature zone includes the range of 6.23D to 14.53Dmm from 6.3D to 13Dmm, the set temperature of 220 ° C is included in (Tm + 50) to (Tm + 80) ° C, and the screw has a conveying element. Provided. In the D temperature zone, 18.68D to 43.58Dmm included a range after 19.3Dmm, and a set temperature of 180 ° C was included in (Tm-20) to (Tm + 40) ° C. Therefore, the B temperature zone corresponds to the first temperature setting zone and the D temperature zone corresponds to the second temperature setting zone, and the condition 1 is satisfied.

  The first kneading part has a start point of 14.9 Dmm and an end point of 16.9 Dmm within a range of 13D to 20.9 Dmm, a length of 2Dmm is 1D to 4Dmm, and a kneading element is provided on the screw. Condition 2 is satisfied.

  The second kneading part has a starting point of 20.9 Dmm within a range of 20.9 Dmm and beyond, a length of 2 Dmm is 1 D to 4 D mm, and a kneading element is provided on the screw.

  In addition, about the following Examples 2-25, the raw material structure conditions and conditions 1-3 of this invention are satisfy | filled similarly.

<Example 2>
A polylactic acid resin composition was produced in the same manner as in Example 1 except that the blending amount of aluminum hydroxide 1 was 50 parts by weight with respect to 100 parts by weight of the polylactic acid resin.

<Example 3>
A polylactic acid resin composition was produced in the same manner as in Example 1 except that the blending amount of aluminum hydroxide 1 was 200 parts by weight with respect to 100 parts by weight of the polylactic acid resin.

<Example 4>
Instead of the surface-treated aluminum hydroxide 1, 99% by weight of talc (trade name: Microace P6, manufactured by Nippon Talc Co., Ltd.) is used as an isocyanate-based silane coupling agent (3-isocyanatepropyltriethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.). Name: KBE-9007) A polylactic acid resin composition was produced in the same manner as in Example 1 except that 100 parts by weight of talc 1 having been surface-treated with 100% by weight of polylactic acid resin was blended. This was taken as Example 4.

<Example 5>
Using a screw outer diameter D is 37mm and the screw effective length L _e is 45.65Dmm (= barrel length), also in the screw, the position of 551mm from the position corresponding to the center of the raw material supply port of the barrel (14.9Dmm ) To 74 mm (2 Dmm) in length (first kneading section) and 74 mm (2 Dmm) in length (second kneading section) from 773 mm position (20.9 Dmm) A polylactic acid resin composition was produced in the same manner as in Example 1 except that the discharge amount Q was 95 kg / hour and the screw rotation speed N was 280 rpm. At this time, Q / N is 0.339.

<Example 6>
Using a screw outer diameter D is 58mm and the screw effective length L _e is 45.65Dmm (= barrel length), also in the screw, the position of 864mm from the position corresponding to the center of the raw material supply port of the barrel (14.9Dmm ) To 116 mm (2 Dmm) length part (first kneading part), and a 1212 mm position (20.9 Dmm) to 116 mm (2 Dmm) length part (second kneading part). A polylactic acid resin composition was produced in the same manner as in Example 1 except that the discharge amount Q was 290 kg / hour and the screw rotation speed N was 220 rpm. At this time, Q / N is 1.32.

<Example 7>
Screw (screw effective length of a length corresponding thereto as well as the number of barrels unit eight L _e: 33.20Dmm, length of the portion of the downstream side from the position corresponding to the center of the raw material supply port of the barrel of the effective screw portion it was prepared analogously to the polylactic acid resin composition as in example 1 except for using the ratio (L ₁ /D):31.13) to the outer diameter D of the of L ₁ screw, it example 7 did. The sixth to eighth units of the barrel correspond to the D temperature zone (18.68D to 31.13 Dmm (zone length: 12.45 Dmm)).

<Example 8>
Screw (screw effective length of a length corresponding to the same time the number of barrels units and 15 L _e: 62.25Dmm, length of the portion of the downstream side from the position corresponding to the center of the raw material supply port of the barrel of the effective screw portion it was prepared analogously to the polylactic acid resin composition as in example 1 except for using the ratio (L ₁ /D):60.18) to the outer diameter D of the of L ₁ screw, it example 8 did. The position of each unit in the barrel length direction is 43.58D to 47.73Dmm for the 12th unit, 47.73D to 51.88Dmm for the 13th unit, 51.88D to 56.03Dmm for the 14th unit, And the 15th unit is 56.03D-60.18Dmm. The 6th to 15th units of the barrel correspond to the D temperature zone (18.68D to 60.18 Dmm (zone length: 41.50 Dmm)).

<Example 9>
A polylactic acid resin composition was produced in the same manner as in Example 1 except that the set temperature of the A temperature zone was 20 ° C., and this was designated as Example 9.

<Example 10>
A polylactic acid resin composition was produced in the same manner as in Example 1 except that the set temperature of the A temperature zone was 240 ° C., and this was designated as Example 10.

<Example 11>
A polylactic acid resin composition was produced in the same manner as in Example 1 except that the set temperature of the B temperature zone was 210 ° C., and this was designated as Example 11.

<Example 12>
A polylactic acid resin composition was produced in the same manner as in Example 1 except that the set temperature of the B temperature zone was 240 ° C., and this was designated as Example 12.

<Example 13>
A polylactic acid resin composition was produced in the same manner as in Example 1 except that the set temperature of the C temperature zone was 140 ° C., and this was designated as Example 13.

<Example 14>
A polylactic acid resin composition was produced in the same manner as in Example 1 except that the temperature set in the C temperature zone was 240 ° C., and this was designated as Example 14.

<Example 15>
A polylactic acid resin composition was produced in the same manner as in Example 1 except that the set temperature of the D temperature zone was 140 ° C., and this was designated as Example 15.

<Example 16>
A polylactic acid resin composition was produced in the same manner as in Example 1 except that the set temperature of the D temperature zone was 200 ° C., and this was designated as Example 16.

<Example 17>
A polylactic acid resin composition was prepared in the same manner as in Example 1 except that the first kneading part was provided in a portion having a length of 549 mm from the center position of the raw material supply port (13.4 Dmm) to 82 mm (2 Dmm). This was produced as Example 17.

<Example 18>
A polylactic acid resin composition was prepared in the same manner as in Example 1 except that the first kneading part was provided in a portion having a length of 771 mm (18.8 Dmm) to 82 mm (2 Dmm) from the center position of the raw material supply port. This was produced as Example 18. In the production of the polylactic acid resin composition of Example 18, the first and second kneading sections were continuously provided.

<Example 19>
A polylactic acid resin composition was prepared in the same manner as in Example 1 except that the first kneading part was provided in a portion having a length of 611 mm from the center position of the raw material supply port (14.9 Dmm) to 164 mm (4 Dmm). This was produced as Example 19.

<Example 20>
A polylactic acid resin composition was prepared in the same manner as in Example 1 except that the second kneading part was provided in a portion having a length of 1349 mm from the center position of the raw material supply port (32.9 Dmm) to 82 mm (2 Dmm). This was produced as Example 20.

<Example 21>
A polylactic acid resin composition was prepared in the same manner as in Example 1 except that the second kneading part was provided in a portion having a length of 857 mm from the center position of the raw material supply port (20.9 Dmm) to 164 mm (4 Dmm). This was produced as Example 21.

<Example 22>
Instead of aluminum hydroxide 1, 99% by weight of aluminum hydroxide (Nippon Light Metal Co., Ltd., trade name: B703), amino-based silane coupling agent (N-phenyl-3-aminopropyltrimethoxysilane, Shin-Etsu Chemical Co., Ltd.) A polylactic acid resin composition was prepared in the same manner as in Example 1 except that 100 parts by weight of aluminum hydroxide 2 having a surface treatment of 1% by weight manufactured by KBM-573) was blended with 100 parts by weight of the polylactic acid resin. This was produced as Example 22.

<Example 23>
Mercapto silane coupling agent (3-mercaptopropyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd., KBM-) with respect to 99% by weight of aluminum hydroxide (manufactured by Nippon Light Metal Co., Ltd., trade name: B703) instead of aluminum hydroxide 1 A polylactic acid resin composition was produced in the same manner as in Example 1 except that 100 parts by weight of aluminum hydroxide 3 having a surface treatment of 1% by weight of 803) was blended with respect to 100 parts by weight of the polylactic acid resin. To Example 23.

<Example 24>
10 parts by weight of plasticizer 1 (methyltriglycol succinic acid diester), 100 parts by weight of polylactic acid resin, crystal nucleating agent 1 (product name: SLIPAX H, manufactured by Nippon Kasei Co., Ltd.), having a hydroxyl group and an amide group in the molecule Bisamide) 0.5 parts by weight, crystal nucleating agent 2 (manufactured by Nissan Chemical Co., Ltd., trade name: PPA-Zn, zinc phenylphosphonate) 0.5 parts by weight, and hydrolysis inhibitor (manufactured by Rhein Chemie, trade name: Stavaxol I- LF) A polylactic acid resin composition was produced in the same manner as in Example 1 except that 1 part by weight was further blended.

  In addition, the plasticizer 1 was produced as follows.

  A 3 L flask equipped with a stirrer, thermometer, and dehydration tube was charged with 500 g of succinic anhydride, 2463 g of triethylene glycol monomethyl ether, and 9.5 g of paratoluenesulfonic acid-hydrate, and nitrogen (500 mL / min) was added to the space. While blowing, the reaction was carried out at 110 ° C. for 15 hours under reduced pressure (4 to 10.7 kPa). The acid value of the reaction solution was 1.6 (KOH mg / g).

  After adding 27 g of adsorbent KYOWARD 500SH (manufactured by Kyowa Chemical Industry Co., Ltd.) to the reaction solution and stirring and filtering at 80 ° C. and 2.7 kPa for 45 minutes, triethylene at a liquid temperature of 115 to 200 ° C. and a pressure of 0.03 kPa. After distilling off glycol monomethyl ether and cooling to 80 ° C., the residual liquid was filtered under reduced pressure to obtain a diester of succinic acid and triethylene glycol monomethyl ether as a filtrate. The obtained diester had an acid value of 0.2 (KOHmg / g), a saponification value of 276 (KOHmg / g), a hydroxyl value of 1 or less (KOHmg / g), and a hue of APHA200.

<Example 25>
For 100 parts by weight of polylactic acid resin, 10 parts by weight of plasticizer 2 (manufactured by Daihachi Chemical Co., Ltd .: DAIFATTY-101, adipic acid diester), crystal nucleating agent 1 (manufactured by Nippon Kasei Co., Ltd., trade name: SLIPAX H, molecule 0.5 parts by weight of bisamide having a hydroxyl group and an amide group), crystal nucleating agent 2 (trade name: PPA-Zn, zinc phenylphosphonate) manufactured by Nissan Chemical Co., Ltd., and hydrolysis inhibitor ( A polylactic acid resin composition was produced in the same manner as in Example 1 except that 1 part by weight of a product manufactured by Rhein Chemie Co., Ltd. (trade name: stavaxol I-LF, carbodiimide compound) was further blended.

<Comparative Example 1>
In place of the surface-treated aluminum hydroxide 1, 100 parts by weight of aluminum hydroxide 4 (product name: B703, manufactured by Nippon Metals Co., Ltd.) that has not been surface-treated is added to 100 parts by weight of the polylactic acid resin, and the B temperature A polylactic acid resin composition was produced in the same manner as in Example 1 except that the set temperature of the zone was 180 ° C., and this was designated as Comparative Example 1.

  In Comparative Example 1, the set temperature of the B temperature zone is 180 ° C., which is 20 ° C. higher than the melting point (Tm = 160 ° C.) of the polylactic acid resin, so that the condition 1 is not satisfied and the surface treatment is not performed Since aluminum 4 is used, the raw material constituent conditions of the present invention are not satisfied.

<Comparative example 2>
A polylactic acid resin composition was prepared in the same manner as in Example 1 except that 100 parts by weight of aluminum hydroxide 4 not subjected to surface treatment was mixed with 100 parts by weight of polylactic acid resin instead of surface-treated aluminum hydroxide 1. This was manufactured as Comparative Example 2.

  In Comparative Example 2, since aluminum hydroxide 4 that has not been subjected to surface treatment is used, the raw material constituent conditions of the present invention are not satisfied.

<Comparative Example 3>
A polylactic acid resin composition was produced in the same manner as in Example 1 except that the set temperature of the B temperature zone was 180 ° C., and this was designated as Comparative Example 3.

  In Comparative Example 3, since the set temperature of the B temperature zone is 180 ° C., Condition 1 is not satisfied.

<Comparative example 4>
A polylactic acid resin composition was produced in the same manner as in Example 1 except that the set temperature of the B temperature zone was 250 ° C., and this was designated as Comparative Example 4.

  In Comparative Example 4, the temperature set in the B temperature zone is 250 ° C., which is 90 ° C. higher than the melting point of the polylactic acid resin (Tm = 160 ° C.), so Condition 1 is not satisfied.

<Comparative Example 5>
A polylactic acid resin composition was produced in the same manner as in Example 1 except that the set temperature of the D temperature zone was 220 ° C., and this was designated as Comparative Example 5.

  In Comparative Example 5, since the set temperature of the D temperature zone is 220 ° C., Condition 1 is not satisfied.

<Comparative Example 6>
A polylactic acid resin composition was prepared in the same manner as in Example 1 except that the first kneading part was provided in a portion having a length of 488 mm from the center position of the raw material supply port (11.9 Dmm) to 82 mm (2 Dmm). This was manufactured as Comparative Example 6.

  In Comparative Example 6, the start point of the first kneading part is 11.9 Dmm upstream from 13 Dmm and the end point is 13.9 Dmm, so Condition 2 is not satisfied.

<Comparative Example 7>
The first kneading section is provided in a portion having a length of 940 mm from the center position of the raw material supply port (22.9 Dmm) to 82 mm (2 Dmm), and the second kneading section is positioned at a position of 1022 mm (24.9 Dmm). A polylactic acid resin composition was produced in the same manner as in Example 1 except that it was provided in a portion having a length of 82 mm (2 Dmm).

  In Comparative Example 7, since the start point of the first kneading part is 22.9 Dmm downstream from 20.9 Dmm and the end point is 24.9 Dmm, Condition 2 is not satisfied.

(Test method)
<Flexibility test; bending fracture strain>
For each of Examples 1 to 25 and Comparative Examples 1 to 7, prismatic test pieces (80 mm × 10 mm × 4 mm) were formed and subjected to a bending test based on JIS K7171, and bending fracture strain was measured. The bending test was performed using Tensilon (Tensilon Universal Testing Machine Model No .: RTC-1210A manufactured by Orientec Co., Ltd.), and the crosshead speed was 2 mm / min. It shows that it is excellent in flexibility, so that the value of bending fracture strain is large. The results are shown in Tables 1-5.

<Heat resistance test; load deflection temperature>
For each of Examples 1 to 25 and Comparative Examples 1 to 7, a prismatic test piece (80 mm × 10 mm × 4 mm) was formed and produced according to JIS K7191, with a load of 1.81 MPa being applied. The load deflection temperature when a deflection of .34 mm occurs was measured. The test was performed using a thermal deformation temperature measuring machine (model number: B-32 manufactured by Toyo Seiki Seisakusho Co., Ltd.). It shows that it is excellent in heat resistance, so that a load deflection temperature value is large. The results are shown in Tables 1-5.

  The present invention is useful for a method for producing a polylactic acid resin composition.

100 In-direction meshing twin screw extruder 10 Screw 111 Conveying element 112 Kneading element 12 Rotating shaft 20 Barrel 20a Raw material supply port 21 Barrel unit 22 Die 23 Screw insertion hole 30 Raw material supply unit 31 Feeder 32 Hopper 40 Rotation drive unit 50 Cooling Tank 60 Pelletizing part M Kneaded material M 'Resin mixture

Claims (3)

A mixture comprising a polylactic acid resin and an inorganic powder subjected to a surface treatment with a content of 50 to 200 parts by weight based on 100 parts by weight of the polylactic acid resin,
A plurality of screws each having an outer diameter D of 30 mm or more in which screw elements including a conveying element and a kneading element are continuously provided along the length direction can be set independently of each other along the length direction. A position corresponding to the center of the raw material supply port of the barrel among the effective screw portion configured to be inserted in parallel with the barrel divided into the portions and the screw elements of the screw to be continuously provided along the length direction. Kneading using the same direction meshing type twin screw extruder in which the ratio (L / D) of the length L of the downstream portion to the outer diameter D of the screw is 30 or more, satisfying the following conditions 1 to 3 A method for producing a polylactic acid resin composition.
Condition 1: It is provided so as to include at least the range of 6.3D to 13Dmm from the center position of the raw material supply port of the barrel, and the set temperature of the barrel is (Tm + 50) to (Tm + 80) where the melting point of the polylactic acid resin is Tm A first temperature setting zone in which the screw is provided with a conveying element, and a range of at least 19.3 Dmm from the center position of the barrel material supply port on the downstream side of the first temperature setting zone. And a second temperature setting zone in which the set temperature of the barrel is (Tm−20) to (Tm + 40) ° C.
Condition 2: It is provided to have a start point and an end point within a range of 13D to 20.9Dmm from the center position of the raw material supply port of the barrel, the length is 1D to 4Dmm, and the kneading element is provided to the screw It has a 1st kneading part.
Condition 3: Second kneading provided with a starting point within a range of 20.9 Dmm or more from the center position of the raw material supply port of the barrel, a length of 1 D to 4 D mm, and a kneading element provided on the screw Part.   The method for producing a polylactic acid resin composition according to claim 1, wherein the inorganic powder contains a metal hydroxide and / or a layered silicate.   The method for producing a polylactic acid resin composition according to claim 1, wherein the mixture further includes a plasticizer and a crystal nucleating agent.

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