JP2009242443A - Polylactic acid block copolymer, method for producing it, and molded product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polylactic acid block copolymer having a high glass transition point and high molecular weight, in favorable embodiments, having excellent hue, and to provide a method for producing the polylactic acid block copolymer and its molded product. <P>SOLUTION: The polylactic acid block copolymer comprises a polylactic acid unit and an aromatic polyester unit, has a glass transition point of 70-130°C, and has number average molecular weight of 50,000 or more. Preferably, a diol component of the aromatic polyester unit is at least one selected from isosorbide, spiroglycol, bisphenol A, and 1,4-cyclohexanedimethanol. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a polylactic acid block copolymer having a high glass transition point and a high molecular weight, and excellent in hue, and a method for producing the same and a molded product thereof.

  In recent years, polylactic acid has attracted attention as a plant-derived carbon neutral material from the viewpoint of environmental conservation. Polylactic acid can be melt-molded, and since lactic acid, which is a monomer, has been produced at low cost by fermentation using microorganisms, it is expected as a biomass plastic that can replace general-purpose plastics derived from petroleum raw materials. It is gradually being used. However, the glass transition point of polylactic acid is about 60 ° C., which is inferior in heat resistance as compared with other general-purpose polymers. For example, in the case of a food packaging film, clothing fibers using polylactic acid cannot be ironed. Has a problem that it cannot be used in a microwave oven. Therefore, attempts to increase the heat resistance of polylactic acid have been activated in recent years, and in Patent Documents 1 and 2, different monomers such as terephthalic acid and isosorbide are copolymerized, but sufficient heat resistance is obtained because of low molecular weight. Absent.

  The main production methods of polylactic acid include a ring-opening polymerization method in which lactide which is a dimer of lactic acid is ring-opened and polymerized, and a direct polycondensation method in which dehydration polycondensation is performed using lactic acid. Compared with the ring-opening polymerization method, it is said that polylactic acid can be produced at low cost because lactic acid can be directly used as a polymerization raw material without passing through a step of synthesizing lactide.

Patent Documents 3 to 7 describe the direct polycondensation method. However, there are problems that the molecular weight is still low and mechanical properties such as strength cannot be satisfied, a problem that a solvent removal process is necessary due to the use of a solvent, a problem that a longer polymerization time and a further improvement in productivity are necessary. There was a desire to improve them.
JP 2006-213828 A (page 1-14) JP 2006-37055 A (page 1-12) JP-A-8-183840 (page 1-4) JP 2000-297145 A (pages 1-7) JP 2000-297143 A (page 1-9) JP-A-11-106499 (page 1-4) JP 2000-302852 A (page 1-4)

  An object of the present invention is to provide a polylactic acid block copolymer having a high glass transition point and a high molecular weight, and excellent in hue, and a method for producing the same and a molded product thereof.

  In order to solve the above-mentioned problems, the present invention mainly studied the types and compositions of copolymerization components, reaction conditions, and catalysts. As a result, the present invention has a high glass transition point and a high molecular weight. Have also found an excellent polylactic acid block copolymer, a production method thereof, and a molded product, and have reached the present invention.

That is, the present invention is as follows.
1. A polylactic acid block copolymer comprising a polylactic acid unit and an aromatic polyester unit, having a glass transition point in the range of 70 to 130 ° C. and having a number average molecular weight of 50,000 or more.
2. 2. The polylactic acid block copolymer according to 1, wherein the constituent ratio of the polylactic acid unit (x) and the aromatic polyester unit (y) is x / y = 99/1 to 71/29 mol%.
3. The polylactic acid block copolymer according to any one of 1 to 2, wherein the diol component of the aromatic polyester is at least one selected from isosorbide, spiroglycol, bisphenol A, and 1,4-cyclohexanedimethanol Coalescence.
4). 4. The poly according to any one of 1 to 3, wherein the acid component of the aromatic polyester is at least one selected from terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, succinic acid, and phthalic acid. Lactic acid block copolymer.
5. Aromatic polyester oligomer after (B) second step or (C) third step of solvent-free polylactic acid direct polycondensation step using lactic acid and / or its derivative as the main raw material, including the following three steps Or the polymer is mixed, The manufacturing method of the polylactic acid block copolymer in any one of Claims 1-4 characterized by the above-mentioned.
(A) A step of producing a low molecular weight product having a number average molecular weight of less than 10,000 by reacting lactic acid and / or a derivative thereof under at least three conditions selected from the following as the first step.
(A-1) Non-catalyst (a-2) Temperature of 100 to 180 ° C. (a-3) Pressure of 0.13 to 13000 Pa (a-4) Reaction time of 0.3 to 15 hours (B) Second step As a process for producing a prepolymer having a number average molecular weight of 5,000 or more and less than 50,000 by reacting the low molecular weight substance obtained in the first step in the presence of a catalyst.
(C) As a third step, a step of producing a polymer having a number average molecular weight of 50,000 or more by subjecting the prepolymer obtained in the second step to solid phase polymerization at a temperature below the melting point of the prepolymer.
6). 6. The method for producing a polylactic acid block copolymer according to 5, wherein the second step (B) is performed under the following conditions.
(B-1) Temperature of 120 to 240 ° C. (b-2) Pressure of 0.13 to 13000 Pa (C) 3rd process is performed on 120-165 degreeC temperature conditions, The manufacturing method of the polylactic acid block copolymer in any one of 5-6 characterized by the above-mentioned.
8). The polylactic acid block copolymer according to any one of 5 to 7, wherein crystallization treatment is performed at a temperature of 50 to 150 ° C. after the completion of the (B) second step and (C) before the start of the third step. A method for producing a polymer.
9. The polylactic acid block copolymer according to any one of 5 to 8, wherein a catalyst deactivator is added at any stage from the start of the first step (A) to the end of the third step (C). A method for producing a polymer.
10. The polylactic acid block copolymer according to any one of 5 to 9, wherein a device in which a reaction vessel and a reflux device are connected is used in the (A) first step and / or (B) second step. Production method.
11. 11. The production of the polylactic acid block copolymer according to 10, wherein the reaction vessel used in the (A) first step and / or (B) second step is composed of two or more reaction chambers. Method.
12 In any one or more steps selected from (A) the first step, (B) the second step, and (C) the third step, water is removed from the volatile components, and lactic acid and lactide or those The method for producing a polylactic acid block copolymer according to any one of 5 to 11, wherein the low molecular weight polymer is returned to the reaction tank of (A) the first step and / or (B) the second step.
13. As the catalyst in the second step (B), any one or more selected from tin compounds, titanium compounds, lead compounds, zinc compounds, cobalt compounds, iron compounds, lithium compounds, rare earth compounds, and sulfonic acid compounds are used. The manufacturing method of the polylactic acid block copolymer in any one of 5-12 characterized by the above-mentioned.
14 The poly (B) according to any one of claims 5 to 13, wherein (B) one or more selected from tin compounds and one or more selected from sulfonic acid compounds are used as the catalyst in the second step. A method for producing a lactic acid block copolymer.
15. 15. The polylactic acid block copolymer according to 14, wherein the tin compound is tin (II) acetate and / or tin (II) octylate, and the sulfonic acid compound is methanesulfonic acid and / or ethanesulfonic acid. A method for producing a polymer.
16. The method for producing a polylactic acid block copolymer according to any one of 5 to 15, wherein the aromatic polyester oligomer has a number average molecular weight of 500 to 20,000.
17. The method for producing a polylactic acid block copolymer according to any one of 5 to 16, wherein the number average molecular weight of the polymer of the aromatic polyester exceeds 20,000.
18. A molded article comprising the polylactic acid block copolymer according to any one of 1 to 4.

  In a preferred embodiment having a high glass transition point and a high molecular weight, a polylactic acid block copolymer excellent in hue and a molded product thereof can be obtained.

  Hereinafter, the present invention will be described in detail.

  The polylactic acid block copolymer of the present invention has a glass transition point in the range of 70 to 130 ° C, preferably 80 to 120 ° C, more preferably 90 to 110 ° C from the viewpoint of heat resistance.

  The glass transition point specified here is a value measured by a differential scanning calorimeter (DSC), and the measurement conditions are a sample of 10 mg in a nitrogen atmosphere and a heating rate of 20 ° C./min.

  The number average molecular weight of the polylactic acid block copolymer of the present invention is 50,000 or more, and is preferably 50,000 to 1,200,000, more preferably 80,000 to 300,000 in view of excellent mechanical properties and moldability. More preferred is 100,000 to 250,000. The number average molecular weight is a value of number average molecular weight in terms of standard polymethyl methacrylate as measured by gel permeation chromatography (GPC) using hexafluoroisopropanol as a solvent.

  The polylactic acid block copolymer of the present invention comprises a polylactic acid unit and an aromatic polyester unit, and the composition ratio of the polylactic acid unit (x) to the aromatic polyester unit (y) is x / y = 99/1 to 71/29. Preferably, the polylactic acid block copolymer having a high molecular weight and a high glass transition point, and having excellent thermal stability and hue can be obtained efficiently. X / y = 99 / 1 to 80/20 is more preferable, and x / y = 95/5 to 85/15 is particularly preferable.

  The polylactic acid unit is a polymer containing L-lactic acid and / or D-lactic acid as a main component. When L-lactic acid is the main component, it is called poly-L-lactic acid, and D-lactic acid is the main component. The case is called poly-D-lactic acid.

  When the polylactic acid unit is poly-L-lactic acid, it preferably contains 70 mol% or more, more preferably 90 mol% or more, more preferably 95 mol% or more. More preferably, it is more preferably 98 mol% or more.

  When the polylactic acid unit is poly-D-lactic acid, it preferably contains 70 mol% or more, more preferably 90 mol% or more, more preferably 95 mol% or more. More preferably, it is more preferably 98 mol% or more.

  In the present invention, the aromatic polyester unit has a structure obtained by dehydration condensation of a polyvalent carboxylic acid having an aromatic structure and a polyvalent diol, or an aromatic hydroxycarboxylic acid structure. For example, polyvalent carboxylic acids include succinic acid, citric acid, adipic acid, sebacic acid, fumaric acid, terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 5-sodium sulfoisophthalic acid, 5 -Tetrabutylphosphonium sulfoisophthalic acid and the like, and as the polyvalent diol, ethylene glycol, propylene glycol, butanediol, hexanediol, octanediol, neopentyl glycol, isosorbide, spiroglycol, bisphenol A, 1,4-cyclohexanedi Methanol, glycerin, trimethylolpropane, pentaerythritol, trimethylolpropane, pentaerythritol with ethylene oxide or propylene oxide added, diethylene glycol, triethylene glycol Examples of the aromatic hydroxycarboxylic acid include p-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, 4′-hydroxyphenyl-4-benzoic acid, and the like. . Among them, a structure obtained by dehydration condensation of terephthalic acid / isosorbide or terephthalic acid / spiroglycol is preferable, and a structure of terephthalic acid / isosorbide is particularly preferable.

  As long as the performance of the polylactic acid block copolymer obtained in the present invention is not impaired, an aliphatic polyester unit other than polylactic acid may be included, and the aliphatic polyhydric carboxylic acid and the aliphatic polyhydric alcohol are dehydrated and condensed. It consists of a structure or a structure of an aliphatic hydroxycarboxylic acid. Specific examples of the aliphatic hydroxycarboxylic acid include glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 4-hydroxyvaleric acid, 6-hydroxycaproic acid, glycolide, ε-caprolactone glycolide, ε-caprolactone, β-pro Examples include piolactone, δ-butyrolactone, β- or γ-butyrolactone, pivalolactone, and δ-valerolactone.

  In the present invention, the method for producing a polylactic acid block copolymer comprises (B) second step of polylactic acid direct polycondensation step in the absence of solvent using lactic acid and / or a derivative thereof as a main raw material, comprising the following three steps: After or after (C) the third step, the oligomer or polymer of the aromatic polyester is mixed.

(A) A step of producing a low molecular weight product having a number average molecular weight of less than 10,000 by reacting lactic acid and / or a derivative thereof under at least three or more conditions selected from the following as the first step.
(A-1) Non-catalyst (a-2) Temperature of 100 to 180 ° C. (a-3) Pressure of 0.13 to 1300 Pa (a-4) Reaction time of 0.3 to 15 hours (B) Second step As a process for producing a prepolymer having a number average molecular weight of 5,000 or more and less than 50,000 by reacting the low molecular weight substance obtained in the first step in the presence of a catalyst.
(C) As a third step, a step of producing a polymer having a number average molecular weight of 50,000 or more by subjecting the prepolymer obtained in the second step to solid phase polymerization at a temperature below the melting point of the prepolymer.

  First, the manufacturing method of the aromatic polyester of this invention is demonstrated. Although the example of a polyethylene terephthalate is described as a specific example, it is not limited to this.

  Polyethylene terephthalate is usually (1) a process in which terephthalic acid and ethylene glycol are used as raw materials, a low polymer is obtained by direct esterification reaction, and then a high molecular weight polymer is obtained by subsequent polycondensation reaction, (2) dimethyl terephthalate and ethylene glycol As a raw material, a low polymer is obtained by a transesterification reaction, and a high molecular weight polymer is obtained by a subsequent polycondensation reaction. In the transesterification reaction, the reaction proceeds by using a compound such as manganese, calcium, magnesium, zinc, lithium, tin, and the catalyst used in the reaction is inactivated after the transesterification reaction is substantially completed. For this purpose, a phosphorous compound such as phosphoric acid or phosphoric acid trimethyl ester is added. In addition, the low polymer obtained in any stage of the series of reactions of (1) or (2), preferably in the first half of the series of reactions of (1) or (2), may contain phosphorus such as phosphoric acid as a stabilizer. After adding compounds such as titanium dioxide particles and silica particles as a matting agent, additives such as cobalt compounds and manganese compounds as a polymer color adjusting agent, antimony trioxide (III), titanium tetraisopropoxide as a polycondensation catalyst Then, germanium (IV) oxide or the like is added, and the polycondensation reaction proceeds under reduced pressure or high temperature to obtain high molecular weight polyethylene terephthalate. The above reaction can be applied to a batch, semi-batch, or continuous system.

  In addition, it is preferable that the number average molecular weight of the oligomer of the aromatic polyester charged into the polylactic acid direct polycondensation step is 500 or more and 20,000 or less. It is more preferably from 1,000 to 20,000 in that an excellent polylactic acid block copolymer can be obtained efficiently. The number average molecular weight of the aromatic polyester polymer is preferably more than 20,000, and more than 25,000 has a high molecular weight and a high glass transition point, and is excellent in thermal stability and hue. It is more preferable in that the copolymer can be obtained efficiently. In addition, the shape and size of the aromatic polyester is spherical or pellet-like, and the major axis is preferably 5 mm or less, more preferably 3 mm or less, and particularly preferably 1 mm or less from the viewpoint of productivity. . The addition amount of the aromatic polyester is preferably such that the composition ratio of the polylactic acid unit (x) and the aromatic polyester unit (y) corresponds to x / y = 99/1 to 71/29 mol%, and the high molecular weight and X / y = 99/1 to 80/20 is more preferable in that a polylactic acid block copolymer having a high glass transition point and excellent thermal stability and hue can be obtained efficiently. Particularly preferred is y = 95/5 to 85/15.

  The method of mixing the aromatic polyester after (B) the second step or (C) after the end of the third step is not particularly limited, and the method is a method of melt-kneading at or above the melting point of the polylactic acid-based resin or mixing in a solvent. Thereafter, a method for removing the solvent and the like can be mentioned, but a method of melt-kneading at or above the melting point of the polylactic acid-based resin is preferable in that it can be efficiently produced. The melt-kneading method may be a batch method or a continuous method. As the apparatus, a single-screw extruder, a twin-screw extruder, a multi-screw extruder, a plastmill, a kneader, a stirring reactor equipped with a decompression device, or the like is used. It is preferable to use a single screw extruder or a twin screw extruder in that it can be kneaded efficiently and uniformly.

Then, the direct polycondensation process of polylactic acid is demonstrated. Lactic acid and / or its derivatives are used as the main raw material. The derivative is
1) Acid fluoride, acid chloride, and acid bromide of lactic acid,
2) Mixed acid anhydride of lactic acid with other carboxylic acid, sulfonic acid, and phosphoric acid 3) Target acid anhydride of lactic acid 4) Oligomer that is a linear multimer obtained by polymerizing lactic acid, and 5) Cyclic dimer 1,4-dioxa-3,6-dimethylcyclohexane-2,5-dione. The proportion of 1) to 4) in the raw material is 60% by weight or more, and the proportion of 5) is less than 10% by weight. Solvent-free means that in the (A) first step and (B) second step, the liquid substance other than lactic acid is less than 5% by weight of the total reaction solution. Since water promotes the reverse reaction of the polycondensation reaction, most of the water coexisting with the raw material and the water generated by the reaction are removed from the reaction solution at the beginning of (A) the first step. Not considered.

First, the first step will be described. In the present invention, (A) the first step is a step of producing a low molecular weight product having a number average molecular weight of less than 10,000 from lactic acid and / or a derivative thereof under at least three or more conditions selected from the following: The polylactic acid block copolymer having a molecular weight and a high glass transition point, and excellent in thermal stability and hue can be efficiently obtained, and can be produced under conditions satisfying the following four conditions. preferable.
(A-1) Non-catalyst (a-2) Temperature of 100 to 180 ° C. (a-3) Pressure of 0.13 to 13000 Pa (a-4) Reaction time of 0.3 to 15 hours

  In the present invention, the (A) first step is characterized in that it is carried out without a catalyst in that a polylactic acid block copolymer having a high molecular weight and a high glass transition point can be obtained.

  In the present invention, (A) the first step is performed at 100 to 180 ° C. in that a polylactic acid block copolymer having a high molecular weight and a high glass transition point and excellent in hue can be efficiently obtained. It is preferably performed at a temperature of 120 to 170 ° C. in that it can be efficiently obtained a polylactic acid block copolymer having a high glass transition point and excellent hue. It is more preferable to carry out at a temperature of 140 to 160 ° C. In addition, the temperature of the first step (A) may be one stage or may be two or more stages, but preferably has two or more stages in terms of achieving a high glass transition point. The method of reacting at the temperature of 140-180 degreeC after reacting at the temperature of 100-140 degreeC, etc. are mentioned.

  In the present invention, (A) the first step is performed at a pressure of 0.13 to 13000 Pa in that a polylactic acid block copolymer having a high molecular weight can be efficiently obtained. It is preferable to carry out at a pressure of 1 to 10000 Pa, more preferably at a pressure of 10 to 9000 Pa, and at a pressure of 100 to 8000 Pa. More preferably, it is particularly preferably performed at a pressure of 500 to 7000 Pa. In addition, (A) the pressure in the first step may be one step or may be two or more steps, but it is preferably two or more steps in terms of high molecular weight and excellent hue. For example, after reacting at the pressure of 700-13000 Pa, the method of reacting at the pressure of 0.13-7000 Pa is mentioned.

  In the present invention, (A) the first step is 0 in that a polylactic acid block copolymer having a high molecular weight and a high glass transition point and excellent in thermal stability and hue can be efficiently obtained. The reaction time is 3 to 15 hours, and the reaction time is preferably 1 to 10 hours in that a polylactic acid block copolymer having excellent hue can be efficiently obtained. More preferably, the reaction time is 1 to 8 hours, more preferably 1 to 6 hours. Moreover, (A) When performing the temperature and pressure of a 1st process in multiple steps of two or more steps, for example, the temperature of 100-140 degreeC, the pressure of 700-13000 Pa, and reaction time of 0.3 to 10 hours Examples include a method in which the reaction is performed at a temperature of 140 to 180 ° C. and a pressure of 0.13 to 7000 Pa and a reaction time of 0.3 to 10 hours after the reaction. In addition, even if it is a case where temperature and a pressure are performed in multiple steps of two steps or more, the total of the reaction time of (A) 1st process is 0.3 to 15 hours.

  In the present invention, (A) the first step is characterized by producing a low molecular weight body having a number average molecular weight of less than 10,000, and efficiently producing a polylactic acid block copolymer having a high molecular weight and a high glass transition point. It is preferable to produce a low molecular weight body having a number average molecular weight of 1000 to 8000, more preferably a low molecular weight body having a number average molecular weight of 1200 to 6000, and a number average molecular weight of 1500 to 5000. More preferably, a low molecular weight product is produced. The number average molecular weight is a value of number average molecular weight in terms of standard polymethyl methacrylate as measured by gel permeation chromatography (GPC) using hexafluoroisopropanol as a solvent.

  In the present invention, the (A) first step may be a batch method or a continuous method, and the reaction vessel is not particularly limited. For example, a stirring vessel type reaction vessel, a mixer type reaction vessel, a tower type reaction vessel. Further, an extruder type reaction vessel or the like can be used, and these reaction vessels can be used in combination of two or more.

  In the present invention, any reactor can be used in the first step (A), but a polylactic acid block copolymer having a high molecular weight and a high glass transition point and excellent in thermal stability and hue is used. It is preferable to use a device in which a reaction tank and a reflux device are connected in that they can be obtained efficiently.

  In the present invention, the reaction vessel may have one reaction chamber or may be composed of two or more reaction chambers divided by a partition plate or the like, but a polylactic acid block copolymer having a high molecular weight is used. The thing comprised from two or more reaction chambers at the point that it can obtain efficiently is preferable.

  In the present invention, the reflux device is preferably connected to the upper part of the reaction vessel, and more preferably a vacuum pump is connected to the reflux device. In the present invention, the reflux device is for separating volatile components, and works to remove a part of the volatile components from the reaction system and a part of the volatile components to return to the reaction system. Any of those having a condensing part having a water content may be used. Specifically, water is removed from volatile components, and lactic acid and lactide or their low molecular weight polymers are converted into (A) the first step and / or ( B) Any material can be used as long as it is returned to the reaction tank in the second step. Here, as a condenser which comprises a condensation part, methods, such as a double tube type, a multi-tube type, a coil type, a plate type, a plate fin type, a spiral type, and a jacket type, can be mentioned, for example. In the present invention, in order to efficiently return lactic acid and lactide or their low molecular weight polymer to the reaction vessel, the condenser temperature may be set to be equal to or higher than the melting point of lactic acid and lactide or their low molecular weight polymer. Preferably, it is 90 degreeC or more, It is more preferable that it is 100-160 degreeC, It is especially preferable that it is 105-140 degreeC.

  In the first step (A) of the present invention, the inside of the reaction system is preferably as dry as possible, and the L-lactic acid as a raw material is dried or reacted in an inert gas atmosphere such as dry nitrogen. It is effective to increase the molecular weight of the finally obtained polylactic acid block copolymer.

  In the first step (A) of the present invention, the method of taking out the produced low molecular weight substance from the reaction tank after completion of the reaction is not particularly limited, and a method of taking out by extrusion with an inert gas such as nitrogen, a gear pump, etc. The method of taking out by an inert gas, such as nitrogen, is preferable from the point of the handleability of the low molecular weight body which is low viscosity.

  Next, the second step will be described. In the present invention, the (B) second step is a step of producing a prepolymer having a number average molecular weight of 5,000 or more and less than 50,000 by reacting the low molecular weight product obtained in the first step in the presence of a catalyst.

  Here, examples of the catalyst include at least one selected from a tin compound, a titanium compound, a lead compound, a zinc compound, a cobalt compound, an iron compound, a lithium compound, a rare earth compound, and a sulfonic acid compound. , Metal alkoxides, metal halides, organic carboxylates, carbonates, sulfates, oxides and the like are preferable. Specifically, tin powder, tin (II) chloride, tin (IV) chloride, tin (II) bromide, tin (IV) bromide, ethoxy tin (II), t-butoxy tin (IV), isopropoxy Tin (IV), tin (II) acetate, tin (IV) acetate, tin (II) octylate, tin (II) laurate, tin (II) myristate, tin (II) palmitate, tin stearate (II) ), Tin (II) oleate, tin (II) linoleate, tin (II) acetylacetone, tin (II) oxalate, tin (II) lactate, tin (II) tartrate, tin (II) pyrophosphate, p- Phenol sulfonate tin (II), bis (methane sulfonate) tin (II), tin sulfate (II), tin oxide (II), tin oxide (IV), tin sulfide (II), tin sulfide (IV), oxidation Dimethyltin (IV), methylphenyltin (IV) oxide, dibuty oxide Tin (IV), dioctyl tin (IV) oxide, diphenyl tin (IV) oxide, tributyl tin oxide, triethyl tin hydroxide (IV), triphenyl tin hydroxide (IV), tributyl tin hydride, monobutyl tin (IV) Oxide, tetramethyltin (IV), tetraethyltin (IV), tetrabutyltin (IV), dibutyldiphenyltin (IV), tetraphenyltin (IV), tributyltin (IV) acetate, triisobutyltin (IV) acetate, Triphenyltin acetate (IV), dibutyltin diacetate, dibutyltin dioctanoate, dibutyltin (IV) dilaurate, dibutyltin (IV) maleate, dibutyltin bis (acetylacetonate), tributyltin chloride (IV), Dibutyltin dichloride, monobutyltin trichloride, dioctyltin dichloride, triphenyltin (IV) chloride, sulfide Examples include tin compounds such as butyltin, tributyltin sulfate, tin (II) trifluoromethanesulfonate, ammonium hexachlorotin (IV), dibutyltin sulfide, diphenyltin sulfide, triethyltin sulfate, and phthalocyanine tin (II). Tin compounds other than tin (II) chloride are preferred. Also, titanium methoxide, titanium propoxide, titanium isopropoxide, titanium butoxide, titanium isobutoxide, titanium cyclohexyl, titanium phenoxide, titanium chloride, titanium diacetate, titanium triacetate, titanium tetraacetate, titanium (IV) oxide, etc. Titanium compounds, lead diisopropoxy (II), lead monochloride, lead acetate, lead (II) octylate, lead (II) isooctanoate, lead (II) isononanoate, lead (II) laurate, lead oleate (II), lead compounds such as lead (II) linoleate, lead naphthenate, lead (II) neodecanoate, lead oxide, lead (II) sulfate, zinc powder, methyl propoxy zinc, zinc chloride, zinc acetate, octylic acid Zinc (II), zinc naphthenate, zinc carbonate, zinc oxide, zinc sulfate and other zinc compounds, chloride Baltic, cobalt acetate, cobalt (II) octylate, cobalt (II) isooctanoate, cobalt (II) isononanoate, cobalt (II) laurate, cobalt (II) oleate, cobalt (II) linoleate, cobalt naphthenate , Cobalt compounds such as cobalt (II) neodecanoate, cobaltous carbonate, cobaltous sulfate, cobalt (II) oxide, iron (II) chloride, iron (II) acetate, iron (II) octylate, iron naphthenate Iron compounds such as iron carbonate (II), iron sulfate (II), iron oxide (II), propoxy lithium, lithium chloride, lithium acetate, lithium octylate, lithium naphthenate, lithium carbonate, dilithium sulfate, lithium oxide, etc. Lithium compounds, triisopropoxy europium (III), triisopropoxy neo (III), triisopropoxylantan, triisopropoxy samarium (III), triisopropoxy yttrium, isopropoxy yttrium, dysprosium chloride, europium chloride, lanthanum chloride, neodymium chloride, samarium chloride, yttrium chloride, dysprosium triacetate (III ), Europium triacetate (III), lanthanum acetate, neodymium triacetate, samarium acetate, yttrium triacetate, dysprosium carbonate (III), dysprosium carbonate (IV), europium carbonate (II), lanthanum carbonate, neodymium carbonate, samarium carbonate ( II), samarium carbonate (III), yttrium carbonate, dysprosium sulfate, europium (II) sulfate, lanthanum sulfate, neodymium sulfate, samarium sulfate, yttrium sulfate, yttrium dioxide Examples include rare earth compounds such as europium, lanthanum oxide, neodymium oxide, samarium (III) oxide, and yttrium oxide. Other potassium compounds such as potassium isopropoxide, potassium chloride, potassium acetate, potassium octylate, potassium naphthenate, tert-butyl potassium carbonate, potassium sulfate, potassium oxide, copper (II) diisopropoxide, copper chloride (II), copper acetate (II), copper octylate, copper naphthenate, copper sulfate (II), copper compounds such as dicopper carbonate, nickel chloride, nickel acetate, nickel octylate, nickel carbonate, nickel sulfate (II) , Nickel compounds such as nickel oxide, tetraisopropoxyzirconium (IV), zirconium trichloride, zirconium acetate, zirconium octylate, zirconium naphthenate, zirconium carbonate (II), zirconium carbonate (IV), zirconium sulfate, zirconium oxide (II ) Zirconium etc. Compounds, antimony compounds such as triisopropoxyantimony, antimony fluoride (III), antimony fluoride (V), antimony acetate, antimony (III) oxide, magnesium, magnesium diisopropoxide, magnesium chloride, magnesium acetate, lactic acid Magnesium compounds such as magnesium, magnesium carbonate, magnesium sulfate and magnesium oxide, calcium compounds such as diisopropoxy calcium, calcium chloride, calcium acetate, calcium octylate, calcium naphthenate, calcium lactate and calcium sulfate, aluminum and aluminum isopropoxide Aluminum compounds such as aluminum chloride, aluminum acetate, aluminum octylate, aluminum sulfate, aluminum oxide, germanium, tetra Germanium compounds such as sopropoxygermane, germanium oxide (IV), triisopropoxymanganese (III), manganese trichloride, manganese acetate, manganese octylate (II), manganese naphthenate (II), manganese such as manganese sulfate Examples thereof include bismuth compounds such as compounds, bismuth (III) chloride, bismuth powder, bismuth oxide (III), bismuth acetate, bismuth octylate, and bismuth neodecanoate. Also, sodium stannate, magnesium stannate, potassium stannate, calcium stannate, manganese stannate, bismuth stannate, barium stannate, strontium stannate, sodium titanate, magnesium titanate, aluminum titanate, potassium titanate, Compounds composed of two or more metal elements such as calcium titanate, cobalt titanate, zinc titanate, manganese titanate, zirconium titanate, bismuth titanate, barium titanate and strontium titanate are also preferred.

  Moreover, an acid catalyst can also be mentioned, and it can be a Bronsted acid as a proton donor, a Lewis acid as an electron pair acceptor, or an organic acid or an inorganic acid. For example, monocarboxylic acid compounds such as formic acid, acetic acid, propionic acid, heptanoic acid, octanoic acid, octylic acid, nonanoic acid, isononanoic acid, trifluoroacetic acid and trichloroacetic acid, oxalic acid, succinic acid, maleic acid, tartaric acid and malonic acid Dicarboxylic acid compounds such as citric acid and tricarballylic acid, benzenesulfonic acid, n-butylbenzenesulfonic acid, n-octylbenzenesulfonic acid, n-dodecylbenzenesulfonic acid, pentadecylbenzenesulfonic acid, 2 , 5-dimethylbenzenesulfonic acid, 2,5-dibutylbenzenesulfonic acid, o-aminobenzenesulfonic acid, m-aminobenzenesulfonic acid, p-aminobenzenesulfonic acid, 3-amino-4-hydroxybenzenesulfonic acid, 5 -Amino-2-me Rubenzenesulfonic acid, 3,5-diamino-2,4,6-trimethylbenzenesulfonic acid, 2,4-dinitrobenzenesulfonic acid, p-chlorobenzenesulfonic acid, 2,5-dichlorobenzenesulfonic acid, cumenesulfonic acid , Xylenesulfonic acid, o-cresolsulfonic acid, m-cresolsulfonic acid, p-cresolsulfonic acid, p-toluenesulfonic acid, 2-naphthalenesulfonic acid, 1-naphthalenesulfonic acid, isopropylnaphthalenesulfonic acid, dodecylnaphthalenesulfonic acid , Dinonylnaphthalenesulfonic acid, dinonylnaphthalenedisulfonic acid, anthraquinone-2-sulfonic acid, m-benzenedisulfonic acid, 2,5-diamino-1,3-benzenedisulfonic acid, aniline-2,4-disulfonic acid, anthraquinone -1,5- Aromatic sulfonic acids such as disulfonic acid and polystyrene sulfonic acid, methanesulfonic acid, ethanesulfonic acid, 1-propanesulfonic acid, n-octylsulfonic acid, pentadecylsulfonic acid, trifluoromethanesulfonic acid, trichloromethanesulfonic acid, 1, 2-aliphatic sulfonic acids such as ethanedisulfonic acid, sulfonic acid compounds such as cyclopentanesulfonic acid, cyclohexanesulfonic acid and alicyclic sulfonic acids such as camphorsulfonic acid, acidic amino acids such as aspartic acid and glutamic acid, ascorbic acid, retinoin Phosphoric acid monoesters such as acid, phosphoric acid, metaphosphoric acid, phosphorous acid, hypophosphorous acid, polyphosphoric acid, monododecyl phosphate and monooctadecyl phosphate, diesters such as didodecyl phosphate and dioctadecyl phosphate Phosphoric acid compounds such as phosphorous acid monoesters and phosphorous acid diesters, boric acid, hydrochloric acid, also like sulfate. Further, the shape of the acid catalyst is not particularly limited, and any of a solid acid catalyst and a liquid acid catalyst may be used. For example, as the solid acid catalyst, acidic clay, kaolinite, bentonite, montmorillonite, talc, zirconium silicate and Natural minerals such as zeolite, oxides such as silica, alumina, titania and zirconia or oxide composites such as silica alumina, silica magnesia, silica boria, alumina boria, silica titania and silica zirconia, chlorinated alumina, fluorinated alumina, positive Examples thereof include ion exchange resins. In the case where polymerization is carried out using a racemic compound, which is an equal mixture of L-lactic acid and D-lactic acid, using a catalyst having stereoselective polymerizability, poly-L-lactic acid and poly-D-lactic acid are used. Can be manufactured simultaneously.

  In the present invention, a tin compound, a titanium compound, a lead compound, a zinc compound, a cobalt compound, an iron compound, a lithium compound, a rare earth element can be obtained in that a polylactic acid block copolymer having a high molecular weight and a high glass transition point can be obtained. Compounds, antimony compounds, bismuth compounds, acid catalysts are preferred, and in terms of excellent productivity, tin compounds, titanium compounds, lead compounds, zinc compounds, cobalt compounds, iron compounds, lithium compounds, rare earth compounds, sulfonic acid compounds, phosphorus Compounds are more preferable, and tin compounds, titanium compounds, rare earth compounds, sulfonic acid compounds, and phosphorus compounds are more preferable. Further, a tin-based organic carboxylate having two ligands is more preferable in that a polylactic acid block copolymer excellent in thermal stability and hue can be obtained, and tin (II) acetate, Tin (II) octylate is particularly preferred. Further, the catalyst may be used alone or in combination of two or more, but it is used in combination of two or more in that a polylactic acid block copolymer having a high molecular weight and a high glass transition point can be obtained. In view of excellent productivity, it is preferable to use one or more selected from tin compounds and one or more selected from sulfonic acid compounds. Tin (II) acetate and / or tin octylate (II ) And methanesulfonic acid and / or ethanesulfonic acid are more preferable, and it is more preferable to use tin (II) acetate and / or tin (II) octylate and ethanesulfonic acid.

  In the present invention, the amount of the catalyst used in the second step (B) is such that the polylactic acid block copolymer having a high molecular weight and a high glass transition point can be obtained efficiently (L -Lactic acid and / or D-lactic acid) is preferably 0.001 to 2 parts by weight, more preferably 0.001 to 1 part by weight with respect to 100 parts by weight, and the polylactic acid block having excellent thermal stability and hue. In terms of being able to obtain a polymer, 0.001 to 0.5 parts by weight is more preferable, and 0.01 to 0.3 parts by weight is particularly preferable.

  In the present invention, (B) the second step is characterized in that a prepolymer having a number average molecular weight of 5,000 or more and less than 50,000 is produced, and a polylactic acid block copolymer having a high molecular weight is efficiently obtained. It is preferable to produce a prepolymer having a number average molecular weight of 10,000 or more and less than 50,000, more preferably a prepolymer having a number average molecular weight of 25,000 or more and less than 50,000, and a number average molecular weight. It is more preferable to produce a prepolymer having a molecular weight of 30,000 or more and less than 50,000, and it is particularly preferable to produce a prepolymer having a number average molecular weight of 35,000 or more and less than 50,000. The number average molecular weight is a value of number average molecular weight in terms of standard polymethyl methacrylate as measured by gel permeation chromatography (GPC) using hexafluoroisopropanol as a solvent.

  In the present invention, (B) the second step is preferably performed at a temperature of 120 to 240 ° C. in that a polylactic acid block copolymer having a high molecular weight can be obtained efficiently, and a high glass transition point. It is preferable to carry out at a temperature of 130 to 210 ° C., more preferably 140 to 195 ° C., in that a polylactic acid block copolymer having an excellent color and excellent hue can be obtained efficiently. . In addition, the temperature of the (B) second step may be one step or may be two or more steps, but a polylactic acid block copolymer having a high molecular weight and a high glass transition point can be obtained efficiently. In this respect, it is preferable to have two or more stages, for example, a method in which the reaction is performed at a temperature of 120 to 160 ° C. and then the reaction is performed at a temperature of 160 to 240 ° C.

  In the present invention, (B) the second step is preferably carried out at a pressure of 0.13 to 13000 Pa in terms of efficiently obtaining a polylactic acid block copolymer having a high molecular weight. It is preferable to carry out at a pressure of 1 to 10000 Pa, more preferably at a pressure of 10 to 9000 Pa, and at a pressure of 100 to 8000 Pa in that an excellent polylactic acid block copolymer can be obtained efficiently. Is more preferable, and it is particularly preferable to carry out at a pressure of 500 to 7000 Pa. (B) The pressure in the second step may be one step or may be two or more steps, but it is preferably two or more steps in terms of high molecular weight and excellent hue. For example, after reacting at the pressure of 700-13000 Pa, the method of reacting at the pressure of 0.13-7000 Pa is mentioned.

  In the present invention, (B) the second step is carried out with a reaction time of 0.5 to 30 hours in that a polylactic acid block copolymer having a high molecular weight and a high glass transition point can be obtained efficiently. It is preferable that the reaction time is 1 to 15 hours, preferably 2 to 10 hours from the viewpoint that a polylactic acid block copolymer having excellent hue can be efficiently obtained. More preferably, the reaction time is 3 to 8 hours, more preferably 3.5 to 7 hours. Moreover, (B) When performing the temperature and pressure of a 2nd process in multiple steps of two or more steps, for example, it is the temperature of 140-160 degreeC, the pressure of 700-13000 Pa, and reaction time of 0.3 to 15 hours. Examples include a method in which the reaction is performed at a temperature of 160 to 240 ° C. and a pressure of 0.13 to 7000 Pa and a reaction time of 0.3 to 15 hours after the reaction. In addition, even if it is a case where it carries out in multiple steps | paragraphs of temperature and pressure in two steps or more, the sum total of the reaction time of (B) 2nd process is 0.5 to 30 hours.

  In the present invention, the second step (B) may be a batch method or a continuous method, and the reaction vessel is not particularly limited. For example, a stirring vessel type reaction vessel, a mixer type reaction vessel, a tower type reaction vessel. Further, an extruder type reaction vessel or the like can be used, and these reaction vessels can be used in combination of two or more.

  In the present invention, (B) the second step can be carried out using any reactor, but a polylactic acid block copolymer having a high molecular weight and a high glass transition point, and excellent in thermal stability and hue. It is preferable to use a device in which a reaction tank and a reflux device are connected in that they can be obtained efficiently.

  In the present invention, the reaction vessel may have one reaction chamber or may be composed of two or more reaction chambers divided by a partition plate or the like, but a polylactic acid block copolymer having a high molecular weight is used. The thing comprised from two or more reaction chambers at the point that it can obtain efficiently is preferable.

  In the present invention, the reflux device is preferably connected to the upper part of the reaction vessel, and more preferably a vacuum pump is connected to the reflux device. In the present invention, the reflux device is for separating volatile components, and works to remove a part of the volatile components from the reaction system and a part of the volatile components to return to the reaction system. Any of those having a condensing part having a water content may be used. Specifically, water is removed from volatile components, and lactic acid and lactide or their low molecular weight polymers are converted into (A) the first step and / or ( B) Any material can be used as long as it is returned to the reaction tank in the second step. Here, as a condenser which comprises a condensation part, methods, such as a double tube type, a multi-tube type, a coil type, a plate type, a plate fin type, a spiral type, and a jacket type, can be mentioned, for example. In the present invention, in order to efficiently return lactic acid and lactide or their low molecular weight polymer to the reaction vessel, the condenser temperature may be set to be equal to or higher than the melting point of lactic acid and lactide or their low molecular weight polymer. Preferably, it is 90 degreeC or more, It is more preferable that it is 100-160 degreeC, It is especially preferable that it is 105-140 degreeC.

  In the second step (B) of the present invention, the inside of the reaction system is preferably as dry as possible, and the final reaction is to carry out the reaction in an inert gas atmosphere such as dry nitrogen. This is effective for increasing the molecular weight of the copolymer.

  In the second step (B) of the present invention, the method of taking out the produced low molecular weight substance from the reaction vessel after completion of the reaction is not particularly limited, and a method of taking out by extrusion with an inert gas such as nitrogen, a gear pump, etc. The method of taking out by an inert gas, such as nitrogen, is preferable from the point of the handleability of the low molecular weight body which is low viscosity.

  Next, the third step will be described. In the present invention, (C) the third step is a step of producing a polymer having a number average molecular weight of 50,000 or more by subjecting the prepolymer obtained in the second step to solid phase polymerization at a temperature below the melting point of the prepolymer. It is.

  In the present invention, (C) the third step is characterized in that it is carried out at a temperature not higher than the melting point of the prepolymer, and a polylactic acid block copolymer having a high molecular weight and a high glass transition point and excellent in hue is efficiently produced. It is preferable to carry out at the temperature of 120-165 degreeC at the point that it can obtain automatically, It is more preferable to carry out at the temperature of 140-160 degreeC, It is further more preferable to carry out at the temperature of 145-155 degreeC. (C) The temperature of the third step may be one step or may be two or more steps, but it is easy to increase the molecular weight in a short time and is excellent in hue. It is preferable to increase the temperature step by step as the reaction proceeds. For example, a method in which the reaction is performed at a temperature of 120 to 140 ° C. and then the reaction is performed at a temperature of 140 to 165 ° C. .

  In the present invention, (C) the third step is 1 in that a polylactic acid block copolymer having a high molecular weight and a high glass transition point and excellent in thermal stability and hue can be obtained efficiently. It is preferable to carry out for a reaction time of ˜100 hours, and it is preferably carried out for a reaction time of 3 to 80 hours in that a polylactic acid block copolymer having excellent hue can be efficiently obtained, and 5 to 50 hours. It is more preferable to carry out with the reaction time of time, and it is still more preferable to carry out with the reaction time of 10 to 30 hours.

  In addition, when the temperature of the (C) third step is performed in two or more stages, for example, the temperature is 120 to 140 ° C. for 1 to 50 hours as the first step, and the temperature is 140 to 165 ° C. as the second step. 1 to 50 hours, and it is easy to increase the molecular weight in a short time and is excellent in hue, so that the first stage is at a temperature of 120 to 140 ° C. for 5 to 20 hours and the second stage is 140 to 140 hours. More preferably, it is carried out at a temperature of 150 ° C. for 5 to 20 hours, and as a third step for 10 to 30 hours at a temperature of 150 to 165 ° C. In addition, even if it is a case where temperature is performed by the multistage of 2 steps or more, the total of the reaction time of (C) 3rd process is 1 to 100 hours.

  In the present invention, in the third step (C), the pressure condition is not particularly limited, and any of a reduced pressure condition, a normal pressure condition and a pressurized condition may be used, but a polylactic acid block copolymer having a high molecular weight is used. From the viewpoint that it can be obtained efficiently, it is preferable to be under reduced pressure or normal pressure. When performed under reduced pressure conditions, it is preferably performed at a pressure of 0.13 to 1300 Pa. In addition, it is preferably performed at a pressure of 1 to 1000 Pa, more preferably at a pressure of 10 to 900 Pa, more preferably 100 to 800 Pa in that a polylactic acid block copolymer having excellent hue can be efficiently obtained. More preferably, it is performed at a pressure of 500 to 700 Pa. (C) The pressure in the third step may be one step or two or more steps, but it is preferably two or more steps in terms of high molecular weight and excellent hue. For example, after reacting at the pressure of 700-1300 Pa, the method of reacting at the pressure of 0.13-700 Pa is mentioned. When it is carried out under normal pressure conditions, it is preferably carried out under an inert gas stream such as dry nitrogen.

  In the present invention, when the (C) third step is carried out, the shape of the prepolymer is not particularly limited, and any shape such as a lump, a film, a pellet and a powder may be used. It is preferable to use pellets or powder in that it can proceed to the next step. As a method for forming pellets, a melted prepolymer is extruded into strands, pelletized with a strand cutter, dropped into droplets using a dropping nozzle, and contacted with a gas or liquid to form pellets Etc. Moreover, as a method of making into powder, the method of grind | pulverizing using a mixer, a blender, a ball mill, and a hammer grinder is mentioned. In the case of powder, the average particle diameter is preferably 0.01 to 3 mm, more preferably 0.1 to 1 mm, from the viewpoint that solid-phase polymerization can be efficiently performed.

  In the present invention, the (C) third step may be a batch process or a continuous process, and the reaction tank may be a stirred tank reaction tank, a mixer reaction tank, a tower reaction tank, or the like. Two or more reaction vessels can be used in combination.

  In the present invention, in the third step (C), the volatile component is separated, and a vaporizing portion having a function of removing a part of the volatile component outside the reaction system and a part of the volatile component being returned to the reaction system. It is preferable to use an apparatus having a condensing part. Specifically, water is removed from the volatile components, and lactic acid and lactide or their low molecular weight polymers are (A) the first step and / or (B) the first. Any device can be used as long as it is returned to the two-step reaction tank. Here, as a condenser which comprises a condensation part, methods, such as a double tube type, a multi-tube type, a coil type, a plate type, a plate fin type, a spiral type, and a jacket type, can be mentioned, for example. In the present invention, in order to efficiently return lactic acid and lactide or their low molecular weight polymer to the reaction vessel, the condenser temperature may be set to be equal to or higher than the melting point of lactic acid and lactide or their low molecular weight polymer. Preferably, it is 90 degreeC or more, It is more preferable that it is 100-160 degreeC, It is especially preferable that it is 105-140 degreeC.

  The number average molecular weight of the polylactic acid block copolymer obtained by the method of the present invention is 50,000 or more, preferably 50,000 to 1,200,000 in terms of excellent moldability and mechanical properties, and 80,000 to 30 More preferably, it is 10,000, more preferably 100,000 to 250,000. The number average molecular weight is a value of number average molecular weight in terms of standard polymethyl methacrylate as measured by gel permeation chromatography (GPC) using hexafluoroisopropanol as a solvent.

  In the present invention, when the (C) third step is performed, the prepolymer is preferably crystallized, and (B) the crystallization treatment is performed after the second step and (C) before the third step. More preferably.

  The method for crystallization is not particularly limited, and a known method can be used. For example, a method of treating at a crystallization temperature in a gas phase or a liquid phase, a method of volatilizing a solvent after dissolving the prepolymer in a solvent, a method of bringing the prepolymer into contact with the solvent, and a molten prepolymer Examples of the method include cooling and solidifying while performing stretching or shearing operations. From the viewpoint of easy operation, a method of treating at a crystallization temperature in a gas phase or a liquid phase is preferable.

  The crystallization temperature here is not particularly limited as long as it is higher than the glass transition temperature of the prepolymer that can be obtained in the second step (B) and lower than the melting point. A polylactic acid block copolymer having a high molecular weight and a high glass transition point and excellent in hue is more preferably within the range of the temperature rising crystallization temperature and the temperature falling crystallization temperature measured by a type calorimeter (DSC). It is more preferable that it is 30-170 degreeC at the point that it can obtain efficiently, It is especially preferable that it is 50-150 degreeC, It is most preferable that it is 100-140 degreeC.

  Further, the time for crystallization is not particularly limited, but it is sufficiently crystallized within 12 hours, and even within 8 hours is preferable. The pressure condition in the crystallization process may be any of reduced pressure, normal pressure and increased pressure.

  In the present invention, the shape of the prepolymer at the time of crystallization treatment is not particularly limited, and any of a lump, a film, a pellet, and a powder may be used, but the pellet or the powder can be efficiently crystallized. Is preferably used. As a method for forming pellets, a melted prepolymer is extruded into strands, pelletized with a strand cutter, dropped into droplets using a dropping nozzle, and contacted with a gas or liquid to form pellets Etc. Moreover, as a method of making into powder, the method of grind | pulverizing using a mixer, a blender, a ball mill, and a hammer grinder is mentioned. In the case of powder, the average particle diameter is preferably 0.01 to 3 mm, more preferably 0.1 to 1 mm, in that it can be efficiently crystallized.

  In the present invention, it is preferable to add a catalyst deactivator at any stage from the start of the first step (A) to the end of the third step (C) in terms of excellent thermal stability. When the polymerization catalyst remains, the polylactic acid block copolymer may be thermally decomposed during melt kneading and melt molding by the remaining catalyst, and thermal decomposition can be suppressed by adding a catalyst deactivator. , Thermal stability can be improved.

  Examples of the catalyst deactivator in the present invention include hindered phenol compounds, thioether compounds, vitamin compounds, triazole compounds, polyvalent amine compounds, hydrazine derivative compounds, phosphorus compounds, and the like. You may use together. Among them, it is preferable to include at least one phosphorus compound, and it is more preferable to use a phosphate compound or a phosphite compound. As further preferred examples of specific examples, “ADEKA STAB” AX-71 (dioctadecyl phosphate), PEP-8 (distearyl pentaerythritol diphosphite), PEP-36 (cyclic neopentatetrayl bis (2,6) manufactured by ADEKA) -T-butyl-4-methylphenyl) phosphite).

  Specific examples of the hindered phenol compound include n-octadecyl-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) -propionate, n-octadecyl-3- (3′-methyl). -5'-t-butyl-4'-hydroxyphenyl) -propionate, n-tetradecyl-3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) -propionate, 1,6-hexane Diol-bis- [3- (3,5-di-t-butyl-4-hydroxyphenyl) -propionate], 1,4-butanediol-bis- [3- (3,5-di-t-butyl- 4-hydroxyphenyl) -propionate], 2,2′-methylenebis- (4-methyl-t-butylphenol), triethylene glycol-bis- [3- (3-t-butyl) 5-methyl-4-hydroxyphenyl) -propionate], tetrakis [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane, 3,9-bis [2- {3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy} -1,1-dimethylethyl] 2,4,8,10-tetraoxaspiro (5,5) undecane, N, N′-bis-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionylhexamethylenediamine, N, N′-tetramethylene-bis-3- (3′-methyl-5) '-T-butyl-4'-hydroxyphenol) propionyldiamine, N, N'-bis- [3- (3,5-di-t-butyl-4-hydroxyphenol) propionyl] Dorazine, N-salicyloyl-N′-salicylidenehydrazine, 3- (N-salicyloyl) amino-1,2,4-triazole, N, N′-bis [2- {3- (3,5-di- t-butyl-4-hydroxyphenyl) propionyloxy} ethyl] oxyamide, pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], N, N′-hexamethylene Bis- (3,5-di-t-butyl-4-hydroxy-hydrocinnamide) and the like. Preferably, triethylene glycol-bis- [3- (3-t-butyl-5-methyl- 4-hydroxyphenyl) -propionate], tetrakis [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate Acid] methane, 1,6-hexanediol-bis- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) -propionate], pentaerythrityl-tetrakis [3- (3,5- Di-t-butyl-4-hydroxyphenyl) propionate], N, N′-hexamethylenebis- (3,5-di-t-butyl-4-hydroxy-hydrocinnamide). Specific product names of the hindered phenol compounds include “ADEKA STAB” AO-20, AO-30, AO-40, AO-50, AO-60, AO-70, AO-80, AO-330 manufactured by ADEKA. “Irganox” 245, 259, 565, 1010, 1035, 1076, 1098, 1222, 1330, 1425, 1520, 3114, 5057, manufactured by Ciba Specialty Chemicals, “Sumilyzer” BHT-R, MDP-S, manufactured by Sumitomo Chemical Co., Ltd. Examples include BBM-S, WX-R, NW, BP-76, BP-101, GA-80, GM, GS, “Sianox” CY-1790 manufactured by Cyanamid.

  Specific examples of the thioether compound include dilauryl thiodipropionate, ditridecyl thiodipropionate, dimyristyl thiodipropionate, distearyl thiodipropionate, pentaerythritol tetrakis (3-lauryl thiopropionate) Pentaerythritol-tetrakis (3-dodecylthiopropionate), pentaerythritol-tetrakis (3-octadecylthiopropionate), pentaerythritol-tetrakis (3-myristylthiopropionate), pentaerythritol-tetrakis (3- Stearylthiopropionate). Specific trade names of thioether compounds include “ADEKA STAB” AO-23, AO-412S, AO-503A from ADEKA, “Irganox” PS802 from Ciba Specialty Chemicals, “Sumilyzer” TPL-R from Sumitomo Chemical, Examples thereof include TPM, TPS, TP-D, DSTP manufactured by API Corporation, DLTP, DLTOIB, DMTP, “Sinox” 412S manufactured by Cypro Kasei, and “Sianox” 1212 manufactured by Cyamide.

  Specific examples of the vitamin compound include d-α-tocopherol acetate, d-α-tocopherol succinate, d-α-tocopherol, d-β-tocopherol, d-γ-tocopherol, d-δ-tocopherol, d- Natural products such as α-tocotrienol, d-β-tocofetrienol, d-γ-tocofetrienol, d-δ-tocofetrienol, dl-α-tocopherol, dl-α-tocopherol acetate, succinic acid Synthetic products such as dl-α-tocopherol calcium and dl-α-tocopherol nicotinate can be mentioned. Specific product names of vitamin compounds include “Tocopherol” manufactured by Eisai, “Irganox” E201 manufactured by Ciba Specialty Chemicals, and the like.

  Specific examples of the triazole compound include benzotriazole, 3- (N-salicyloyl) amino-1,2,4-triazole, and the like.

  Specific examples of the polyvalent amine compound include 3,9-bis [2- (3,5-diamino-2,4,6-triazaphenyl) ethyl] -2,4,8,10-tetraoxaspiro. [5.5] Undecane, ethylenediamine-tetraacetic acid, alkali metal salt (Li, Na, K) of ethylenediamine-tetraacetic acid, N, N′-disalicylidene-ethylenediamine, N, N′-disalicylidene-1 , 2-propylenediamine, N, N ″ -disalicylidene-N′-methyl-dipropylenetriamine, 3-salicyloylamino-1,2,4-triazole and the like.

  Specific examples of the hydrazine derivative-based compound include decamethylene dicarboxyl acid-bis (N′-salicyloyl hydrazide), bis (2-phenoxypropionyl hydrazide) isophthalate, N-formyl-N′-salicyloyl hydrazine. 2,2-oxamide bis- [ethyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], oxalyl-bis-benzylidene-hydrazide, nickel-bis (1-phenyl-3- Methyl-4-decanoyl-5-pyrazolate), 2-ethoxy-2′-ethyloxanilide, 5-t-butyl-2-ethoxy-2′-ethyloxanilide, N, N-diethyl-N ′, N'-diphenyloxamide, N, N'-diethyl-N, N'-diphenyloxamide, oxalic Cyd-bis (benzylidenehydrazide), thiodipropionic acid-bis (benzylidenehydrazide), bis (salicyloylhydrazine), N-salicylidene-N′-salicyloylhydrazone, N, N′-bis [3- ( 3,5-di-tert-butyl-4-hydroxyphenyl) propionyl] hydrazine, N, N′-bis [2- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy] Ethyl] oxamide and the like.

  Examples of phosphorus compounds include phosphite compounds and phosphate compounds. Specific examples of such phosphite compounds include tetrakis [2-t-butyl-4-thio (2′-methyl-4′-hydroxy-5′-t-butylphenyl) -5-methylphenyl] -1, 6-hexamethylene-bis (N-hydroxyethyl-N-methylsemicarbazide) -diphosphite, tetrakis [2-t-butyl-4-thio (2'-methyl-4'-hydroxy-5'-t-butylphenyl) -5-methylphenyl] -1,10-decamethylene-di-carboxylic acid-di-hydroxyethylcarbonylhydrazide-diphosphite, tetrakis [2-t-butyl-4-thio (2'-methyl-4'-hydroxy-) 5'-t-butylphenyl) -5-methylphenyl] -1,10-decamethylene-di-carboxylic acid- -Salicyloylhydrazide-diphosphite, tetrakis [2-tert-butyl-4-thio (2'-methyl-4'-hydroxy-5'-tert-butylphenyl) -5-methylphenyl] -di (hydroxyethylcarbonyl) ) Hydrazide-diphosphite, tetrakis [2-tert-butyl-4-thio (2′-methyl-4′-hydroxy-5′-tert-butylphenyl) -5-methylphenyl] -N, N′-bis (hydroxy) Ethyl) oxamide-diphosphite and the like, and at least one P—O bond is more preferably bonded to an aromatic group, and specific examples include tris (2,4-di-t-butylphenyl). Phosphite, tetrakis (2,4-di-t-butylphenyl) 4,4'-biphenylene phosphonite, bis (2,4-di-t- Tilphenyl) pentaerythritol-di-phosphite, bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol-di-phosphite, 2,2-methylenebis (4,6-di-t-butyl) Phenyl) octyl phosphite, 4,4′-butylidene-bis (3-methyl-6-tert-butylphenyl-di-tridecyl) phosphite, 1,1,3-tris (2-methyl-4-ditridecylphos) Phyto-5-t-butyl-phenyl) butane, tris (mixed mono and di-nonylphenyl) phosphite, tris (nonylphenyl) phosphite, 4,4′-isopropylidenebis (phenyl-dialkyl phosphite), etc. Tris (2,4-di-t-butylphenyl) phosphite, 2,2-methylenebis (4,6-di-t-butylphenyl) octyl phosphite, bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol di-phosphite, tetrakis (2,4-di-t -Butylphenyl) -4,4'-biphenylenephosphonite can be preferably used. Specific product names of phosphite compounds include “ADEKA STAB” C, PEP-4C, PEP-8, PEP-11C, PEP-24G, PEP-36, HP-10, 2112, 260, 522A, manufactured by ADEKA, 329A, 1178, 1500, C, 135A, 3010, TPP, “Irgaphos” 168, manufactured by Ciba Specialty Chemicals, “Sumilyzer” P-16, manufactured by Sumitomo Chemical, “Sand Stub” manufactured by Clariant, P-EPQ, “Weston” manufactured by GE 618, 619G, 624 and the like.

  Specific examples of the phosphate compound include monostearyl acid phosphate, distearyl acid phosphate, methyl acid phosphate, isopropyl acid phosphate, butyl acid phosphate, octyl acid phosphate, isodecyl acid phosphate, etc., among them monostearyl acid phosphate Distearyl acid phosphate is preferred. Specific product names of phosphate compounds include “Irganox” MD1024 from Ciba Specialty Chemicals, “Inhibitor” OABH from Eastman Kodak, “Adekastab” CDA-1, CDA-6, AX-71 from ADEKA, etc. Can be mentioned.

  The addition amount of the catalyst deactivator is not particularly limited, but is preferably 0.001 to 2 parts by weight with respect to 100 parts by weight of the polylactic acid block copolymer in terms of excellent thermal stability. The amount is more preferably 0.01 to 1 part by weight, still more preferably 0.05 to 0.5 part by weight, and most preferably 0.08 to 0.3 part by weight. The timing of addition of the catalyst deactivator is not particularly limited, and may be any before or after the start of each of the first step, the second step, and the third step, but it has a high glass transition point and a high molecular weight polylactic acid block. In terms of being able to obtain a copolymer, it is preferably added in the stage of the first step or the second step, and in terms of excellent productivity, immediately before the end of the first step or in the second step. It is more preferable to add at the start of the step, and it is even more preferable to add them immediately before the end of the first step and at the start of the second step. In addition, when adding at the start of a 2nd process, it is preferable to add the catalyst for solid-phase polymerization after adding a catalyst deactivator. When adding in each step of the first step or the second step, it is preferable to add 0.001 to 1 part by weight with respect to 100 parts by weight of the polylactic acid block copolymer, which is excellent in productivity. In this respect, 0.01 to 0.5 parts by weight is more preferably added, and 0.01 to 0.1 parts by weight is more preferably added. Moreover, it is also preferable to add a catalyst deactivator after completion of the third step in that a polylactic acid block copolymer having excellent thermal stability can be obtained.

  In the present invention, the method of adding the catalyst deactivator is not particularly limited, and includes a method of melt kneading at a melting point or higher of the polylactic acid block copolymer, a method of removing the solvent after mixing in a solvent, and the like. Although it can mention, the method of melt-kneading above the melting point of a polylactic acid block copolymer is preferable at the point which can manufacture efficiently. The melt-kneading method may be a batch method or a continuous method. As the apparatus, a single-screw extruder, a twin-screw extruder, a multi-screw extruder, a plastmill, a kneader, a stirring reactor equipped with a decompression device, or the like is used. It is preferable to use a single screw extruder or a twin screw extruder in that it can be kneaded efficiently and uniformly.

  In the present invention, the temperature at which the catalyst deactivator is added is preferably from 180 to 300 ° C., and more preferably from 190 to 250 ° C. in terms of excellent mechanical properties.

  In the present invention, the pressure at which the catalyst deactivator is added may be any of reduced pressure, normal pressure, and increased pressure, and is preferably reduced in that the generated gas can be removed during melt-kneading.

  In the present invention, the atmospheric conditions at the time of melt kneading may be either an air atmosphere or an inert gas atmosphere such as nitrogen, but in an inert gas atmosphere in that the amount of gas generated at the time of melt kneading can be reduced. It is preferable to carry out with.

  When mixing in a solvent, a solvent in which the polymer and the monomer are dissolved is used. As the solvent, for example, chloroform, methylene chloride, acetonitrile and the like can be used. The method for removing the solvent when it is necessary to remove the solvent after mixing is not particularly limited. For example, the solvent is volatilized at room temperature and the solvent is volatilized at a temperature equal to or higher than the boiling point of the solvent under reduced pressure. Or the like can be used.

  In the polylactic acid block copolymer obtained by the production method of the present invention, ordinary additives such as fillers (glass fiber, carbon fiber, metal fiber, natural fiber, organic fiber, and organic fiber) are used as long as the object of the present invention is not impaired. Fibers, glass flakes, glass beads, ceramic fibers, ceramic beads, asbestos, wollastonite, talc, clay, mica, sericite, zeolite, bentonite, montmorillonite, synthetic mica, dolomite, kaolinite, fine silica, feldspar powder, Potassium titanate, Shirasu balloon, Calcium carbonate, Magnesium carbonate, Barium sulfate, Calcium oxide, Aluminum oxide, Titanium oxide, Aluminum silicate, Silicon oxide, Gypsum, Novacurite, Dawsonite or clay, UV absorber (resorcinol, salicylate) , Benzotriazole, benzophenone, etc.), heat stabilizer (hindered phenol, hydroquinone, phosphites and their substitutes, etc.), lubricant, mold release agent (montanic acid and its salt, its ester, its half ester, stearyl alcohol) , Stearamide and polyethylene waxes), colorants including dyes (such as nigrosine) and pigments (such as cadmium sulfide, phthalocyanine), anti-coloring agents (such as phosphites, hypophosphites), flame retardants (red phosphorus, Phosphate ester, brominated polystyrene, brominated polyphenylene ether, brominated polycarbonate, magnesium hydroxide, melamine and cyanuric acid or salts thereof, conductive agent or colorant (carbon black, etc.), slidability improver (graphite, fluorine Resin) Nucleating agents (inorganic nucleating agents such as talc, organic amide compounds such as ethylenebislauric acid amide, ethylenebis-12-dihydroxystearic acid amide and trimesic acid tricyclohexylamide, pigment nuclei such as copper phthalocyanine and pigment yellow 110 1 type, or 2 or more types, such as an agent, organic carboxylic acid metal salt, zinc phenylphosphonate, etc.) and an antistatic agent can be added.

  In addition, the polylactic acid block copolymer obtained by the production method of the present invention includes other thermoplastic resins (for example, polyethylene, polypropylene, acrylic resin, polyamide, polyphenylene sulfide resin, as long as the object of the present invention is not impaired). Polyether ether ketone resin, polyester, polysulfone, polyphenylene oxide, polyacetal, polyimide, polyetherimide, etc.) or thermosetting resin (eg phenol resin, melamine resin, polyester resin, silicone resin, epoxy resin, etc.) or soft thermoplastic Less resin (eg, ethylene / glycidyl methacrylate copolymer, polyester elastomer, polyamide elastomer, ethylene / propylene terpolymer, ethylene / butene-1 copolymer, etc.) It may also further contain one or more.

  The polylactic acid block copolymer obtained by the production method of the present invention has a high molecular weight after it is once melted and solidified when it is processed into a molded article, and in a preferred embodiment, it has a high glass transition point. It is easy to form a polylactic acid block copolymer having excellent thermal stability and hue.

  The polylactic acid block copolymer obtained by the production method of the present invention can be widely used as a molded product. Examples of molded products include films, sheets, fibers / clothes, non-woven fabrics, injection molded products, extrusion molded products, vacuum / pressure molded products, blow molded products, and composites with other materials. The article is useful for agricultural materials, horticultural materials, fishery materials, civil engineering / architectural materials, stationery, medical supplies, automotive parts, electrical / electronic components or other uses.

Hereinafter, the present invention will be described specifically by way of examples.
The measurement method and determination method used in the present invention are shown below.

(1) Number average molecular weight (Mn)
It is the value of the number average molecular weight in terms of standard polymethyl methacrylate measured by gel permeation chromatography (GPC). GPC measurement is performed using a WATERS differential refractometer WATERS410 as a detector, a MODEL510 high-performance liquid chromatography as a pump, and a column with Shodex GPC HFIP-806M and Shodex GPC HFIP-LG connected in series. It was. The measurement conditions were a flow rate of 0.5 mL / min, hexafluoroisopropanol was used as a solvent, and 0.1 mL of a solution having a sample concentration of 1 mg / mL was injected.

(2) Glass transition point (Tg)
It is a value measured by a differential scanning calorimeter (DSC), and DSC7 manufactured by Perkin Elmer was used, and the measurement conditions were 10 mg of sample in a nitrogen atmosphere at a heating rate of 10 ° C./min.

(3) Hue Judging from visual judgment, the following criteria were used.
5: No coloring 4: Intermediate between 3: 3 and 5: Slight yellow coloring 2: Intermediate between 1: 1 and 3: High coloring

[Example 1]
Synthesis of Aromatic Polyester In a 5 liter reaction vessel (flask) equipped with stirring and heating device, 1000 g of dimethyl terephthalate (manufactured by Mitsubishi Chemical Corporation), 1506 g of isosorbide (manufactured by Rocket Corporation), tin acetate 0 .4 g (manufactured by Kanto Chemical Co., Inc.), pentaerythritol-tetrakis (3- (3,5-di-t-butyl-4-hydroxyphenol) propionate) (manufactured by Ciba Specialty Chemicals Co., Ltd., Irganox 1010) Then, 3.6 g of a liquid dispersed at a concentration of 20% by weight was charged, and the temperature was raised to 260 ° C. over 3 hours, and 325 g of methanol was distilled off to obtain 2160 g of a low polymer. Subsequently, 240 g of a low polymer melted at 245 ° C., 1.23 g of a 2.2 wt% ethylene glycol solution of 85 wt% phosphoric acid aqueous solution (manufactured by Wako Pure Chemical Industries, Ltd.), germanium (IV) oxide 0.43 g of a 10 wt% ethylene glycol solution (manufactured by Sumitomo Metal Co., Ltd.) was added with stirring at intervals of 5 minutes. Thereafter, while the low polymer was stirred at 30 rpm, the reaction system was gradually heated to 285 ° C. and the pressure was reduced to 500 Pa to proceed the polycondensation reaction. The time to reach the final temperature was 120 minutes, and the time to reach the final pressure was 60 minutes. When 3 hours had elapsed from the start of the temperature rise, the reaction system was purged with nitrogen and returned to normal pressure, the polycondensation reaction was stopped, discharged into cold water in a strand form, and immediately cut to obtain 121 g of polymer pellets. Table 1 shows the number average molecular weight of the obtained aromatic polyester.

Direct polycondensation of polylactic acid (A) First step 100 g of 90 wt% L-lactic acid aqueous solution (manufactured by Wako Pure Chemical Industries, Ltd.) is placed in a 300 ml reaction vessel (flask) equipped with a stirrer. The pressure was reduced to 3300 Pa and the temperature was raised to 150 ° C., and the reaction was carried out for 2 hours while removing water to obtain a low molecular weight product (A-1) of Mn2000.

(B) Second Step In a 300 ml reaction vessel (flask) equipped with a stirrer, 100 g of the low molecular weight substance (A-1) was put, and at 173 ° C. under atmospheric pressure and nitrogen atmosphere, tin acetate ( II, manufactured by Kanto Chemical Co., Ltd.) 0.05 g, and methanesulfonic acid (manufactured by Wako Pure Chemical Industries, Ltd.) 0.36 g were added at 5 minute intervals, and gradually reduced in pressure to 500 Pa for 7 hours polycondensation reaction. Then, the pressure was returned to normal pressure with a temporary nitrogen purge, 50 g of aromatic polyester was added, the pressure was reduced and the temperature was increased again, and the mixture was stirred at 700 Pa and 230 ° C. for 0.5 hour to obtain prepolymer (B-1).

(C) Third step After the prepolymer is crystallized at 100 ° C. for 1 hour and pulverized to have an average particle size of 1 mm or less, 100 g of the prepolymer is put into a vacuum dryer under the conditions of 145 ° C. and 50 Pa. For 40 hours to obtain a polylactic acid block copolymer (C-1).

  The results are shown in Table 1 for the polylactic acid block copolymer obtained above.

[Example 2]
(B) In the second step, the same procedure as in Example 1 was performed except that the addition amount of the aromatic polyester was changed to 25 g. The results are shown in Table 1.

[Example 3]
The same procedure as in Example 1 was performed except that the aromatic polyester (C) was mixed after the third step. The results are shown in Table 1.

[Example 4]
The same procedure as in Example 1 was performed except that spiroglycol was used instead of isosorbide. The results are shown in Table 1.

[Example 5]
The same procedure as in Example 1 was performed except that the amount of isosorbide added in the aromatic polyester production process was reduced to 900 g and that an oligomer was added to the polylactic acid polycondensation process instead of the polymer of the aromatic polyester. The results are shown in Table 1.

[Example 6]
It was carried out in the same manner as in Example 5 except that the oligomer was mixed for 30 minutes at 220 ° C. and 20 Torr in a reaction vessel equipped with a stirrer after (C) the third step instead of (B) the second step. The results are shown in Table 1.

[Comparative Example 1]
Into a 5 liter reaction vessel (flask) equipped with a stirrer and a temperature riser was charged 1000 g of dimethyl terephthalate, 1506 g of isosorbide, and 0.57 g of tetrabutyl titanate (manufactured by Kanto Chemical Co., Inc.) at 235 ° C. over 3 hours. The methanol was distilled off to obtain a low polymer. About 10 g of this low polymer, dissolution in 100 g of hexafluoroisopropanol and precipitation (precipitation) by dropping this solution into 1000 g of water were repeated three times and dried under reduced pressure at room temperature. 50 g of this washed and dried low polymer and 50 g of dried L-lactide (Pureac) were polymerized at 140 ° C. for 1 hour in the presence of 0.1 g of tin octylate. The obtained polymer was dissolved in 500 g of chloroform, and precipitation (precipitation) by dropping 100 g of this solution into 1000 g of methanol was repeated three times and dried under reduced pressure at room temperature. However, Tg of the obtained polymer was not observed, and Mn was as low as 25,000. The evaluation results of the obtained polymer are shown in Table 1.

[Comparative Example 2]
In a 300 ml reaction vessel (flask) equipped with a stirrer and a temperature riser, tin octylate diluted with dehydrated toluene to 48 g of dry L-lactide and 17 g of isosorbide in an atmosphere of nitrogen at 150 ° C. and atmospheric pressure was added. 88 g was added and polycondensation was performed for 2 hours to obtain 54 g of a light yellow oligomer. To 20 g of the obtained oligomer, 49 g of dehydrated o-dichlorobenzene and 8.7 g of pyridine (manufactured by Wako Reagent Industry Co., Ltd.) were added, and the temperature was raised to 80 ° C. under normal pressure and a nitrogen stream. After reaching 80 ° C., 18.5 g of isophthalic acid chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) diluted with dehydrated o-dichlorobenzene was added dropwise. After cooling, the reaction solution was charged with chloroform to dissolve the polymer, Furthermore, 1N-hydrochloric acid was charged and stirred at room temperature for 30 minutes. After separation, the polymer was precipitated with n-hexane. After repeating washing with n-hexane, the polymer recovered by filtration was dried at 50 ° C. in a nitrogen atmosphere. Mn of the obtained polymer was 32,000, and Tg was 65 degreeC.

Claims (18)

A polylactic acid block copolymer comprising a polylactic acid unit and an aromatic polyester unit, having a glass transition point in the range of 70 to 130 ° C. and having a number average molecular weight of 50,000 or more. 2. The polylactic acid block copolymer according to claim 1, wherein the composition ratio of the polylactic acid unit (x) to the aromatic polyester unit (y) is x / y = 99/1 to 71/29 mol%. . 3. The polylactic acid block according to claim 1, wherein the diol component of the aromatic polyester is at least one selected from isosorbide, spiroglycol, bisphenol A, and 1,4-cyclohexanedimethanol. Copolymer. The acid component of the aromatic polyester is at least one selected from terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, succinic acid, and phthalic acid. Polylactic acid block copolymer. Aromatic polyester oligomer after (B) 2nd step or (C) 3rd step of polylactic acid direct polycondensation step in the absence of solvent using lactic acid and / or its derivative as main raw material, including the following 3 steps Or the polymer is mixed, The manufacturing method of the polylactic acid block copolymer in any one of Claims 1-4 characterized by the above-mentioned.
(A) A step of producing a low molecular weight product having a number average molecular weight of less than 10,000 by reacting lactic acid and / or a derivative thereof under at least three conditions selected from the following as the first step.
(A-1) Non-catalyst (a-2) Temperature of 100 to 180 ° C. (a-3) Pressure of 0.13 to 13000 Pa (a-4) Reaction time of 0.3 to 15 hours (B) Second step As a process for producing a prepolymer having a number average molecular weight of 5,000 or more and less than 50,000 by reacting the low molecular weight substance obtained in the first step in the presence of a catalyst.
(C) As a third step, a step of producing a polymer having a number average molecular weight of 50,000 or more by subjecting the prepolymer obtained in the second step to solid phase polymerization at a temperature below the melting point of the prepolymer. The method for producing a polylactic acid block copolymer according to claim 5, wherein the second step (B) is performed under the following conditions.
(B-1) Temperature of 120 to 240 ° C. (b-2) Pressure of 0.13 to 13000 Pa The method for producing a polylactic acid block copolymer according to any one of claims 5 to 6, wherein the third step (C) is performed under a temperature condition of 120 to 165 ° C. The polylactic acid according to any one of claims 5 to 7, wherein the crystallization treatment is performed at a temperature of 50 to 150 ° C after the completion of the (B) second step and (C) before the start of the third step. A method for producing a block copolymer. The polylactic acid according to any one of claims 5 to 8, wherein a catalyst deactivator is added at any stage from the start of the first step (A) to the end of the third step (C). A method for producing a block copolymer. The polylactic acid block co-polymerization according to any one of claims 5 to 9, wherein a device in which a reaction vessel and a reflux device are connected is used in the (A) first step and / or (B) second step. Manufacturing method of coalescence. 11. The polylactic acid block copolymer according to claim 10, wherein the reaction tank used in the (A) first step and / or (B) the second step is composed of two or more reaction chambers. Manufacturing method. In any one or more steps selected from (A) the first step, (B) the second step, and (C) the third step, water is removed from the volatile components, and lactic acid and lactide or those The polylactic acid block copolymer according to any one of claims 5 to 11, wherein the low molecular weight polymer is returned to the reaction vessel of (A) the first step and / or (B) the second step. Method. As the catalyst in the second step (B), one or more selected from tin compounds, titanium compounds, lead compounds, zinc compounds, cobalt compounds, iron compounds, lithium compounds, rare earth compounds, and sulfonic acid compounds are used. The method for producing a polylactic acid block copolymer according to any one of claims 5 to 12. The poly (B) according to any one of claims 5 to 13, wherein (B) one or more selected from tin compounds and one or more selected from sulfonic acid compounds are used as the catalyst in the second step. A method for producing a lactic acid block copolymer. 15. The polylactic acid according to claim 14, wherein the tin compound is tin (II) acetate and / or tin (II) octylate, and the sulfonic acid compound is methanesulfonic acid and / or ethanesulfonic acid. A method for producing a block copolymer. The method for producing a polylactic acid block copolymer according to any one of claims 5 to 15, wherein the number average molecular weight of the oligomer of the aromatic polyester is 500 or more and 20,000 or less. The method for producing a polylactic acid block copolymer according to any one of claims 5 to 16, wherein the number average molecular weight of the polymer of the aromatic polyester exceeds 20,000. A molded article comprising the polylactic acid block copolymer according to any one of claims 1 to 4.