WO2012029392A1 - ポリ乳酸ブロック共重合体の製造方法 - Google Patents
ポリ乳酸ブロック共重合体の製造方法 Download PDFInfo
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- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
- C08G63/02—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds
- C08G63/06—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds derived from hydroxycarboxylic acids
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- C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
- C08G63/02—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds
- C08G63/06—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds derived from hydroxycarboxylic acids
- C08G63/08—Lactones or lactides
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- C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
- C08G63/78—Preparation processes
- C08G63/80—Solid-state polycondensation
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- C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
- C08G63/78—Preparation processes
- C08G63/82—Preparation processes characterised by the catalyst used
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- C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
- C08G63/78—Preparation processes
- C08G63/82—Preparation processes characterised by the catalyst used
- C08G63/823—Preparation processes characterised by the catalyst used for the preparation of polylactones or polylactides
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- C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
- C08G63/91—Polymers modified by chemical after-treatment
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- C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
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- C08L67/00—Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Compositions of derivatives of such polymers
- C08L67/04—Polyesters derived from hydroxycarboxylic acids, e.g. lactones
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- C08G2261/00—Macromolecular compounds obtained by reactions forming a carbon-to-carbon link in the main chain of the macromolecule
- C08G2261/10—Definition of the polymer structure
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- C08L2205/00—Polymer mixtures characterised by other features
- C08L2205/02—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group
- C08L2205/025—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure
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- C08L2205/00—Polymer mixtures characterised by other features
- C08L2205/05—Polymer mixtures characterised by other features containing polymer components which can react with one another
Definitions
- the present invention relates to a method for producing a polylactic acid block copolymer having a high molecular weight, a high melting point, and forming a polylactic acid stereocomplex having excellent heat resistance and crystallinity in a high yield.
- Polylactic acid is a polymer that can be melt-molded practically and has biodegradable characteristics, so that it is developed as a biodegradable plastic that is decomposed in the natural environment and released as carbon dioxide or water after use. Has been promoted.
- polylactic acid itself is made from renewable resources (biomass) originating from carbon dioxide and water, so carbon that does not increase or decrease in the global environment even if carbon dioxide is released after use. Neutral properties have attracted attention and are expected to be used as environmentally friendly materials.
- lactic acid which is a monomer of polylactic acid, is being produced at low cost by fermentation using microorganisms, and has been studied as an alternative material for general-purpose polymers made of petroleum-based plastics.
- polylactic acid has lower heat resistance and durability than petroleum-based plastics, and its crystallization speed is low, so it is inferior in productivity, and the range of practical use is greatly limited. .
- Polylactic acid stereocomplex is formed by mixing optically active poly-L-lactic acid (hereinafter referred to as PLLA) and poly-D-lactic acid (hereinafter referred to as PDLA). As a result, the temperature reaches 220.degree. For this reason, application as a high melting point and highly crystalline fiber, film, and resin molded product is tried.
- PLLA optically active poly-L-lactic acid
- PDLA poly-D-lactic acid
- a polylactic acid stereocomplex is formed by mixing PLLA and PDLA in a solution state or by heat-melting and mixing PLLA and PDLA.
- the solution mixing of PLLA and PDLA has a problem that the manufacturing process becomes complicated because the solvent needs to be volatilized after mixing, resulting in high cost of the polylactic acid stereocomplex.
- polylactic acid block copolymers composed of PLLA segments and PDLA segments have been disclosed as techniques for forming a stereocomplex with high molecular weight (Patent Documents 1 to 4).
- Patent Document 1 after preparing a mixture by melt-kneading PLLA and PDLA prepared by ring-opening polymerization or direct polycondensation under heating, a polylactic acid block copolymer is obtained by solid-phase polymerization of the mixture. It has gained.
- Patent Document 2 prepares a polylactic acid block copolymer by melt-mixing PLLA and PDLA obtained by melt polymerization under heating and then solid-phase polymerizing the mixture.
- a polylactic acid block copolymer is prepared by mixing PLLA and PDLA in the vicinity of a melting point and solid-phase polymerizing them in the presence of polylactic acid homocrystals.
- Patent Document 4 obtains a polylactic acid block copolymer by mixing PLLA and PDLA obtained by direct polycondensation at a melting point or higher and then solid-phase polymerizing the mixture.
- Patent Document 1 it is necessary to heat to a temperature equal to or higher than the melting point of the polylactic acid stereocomplex during melt-kneading, and the molecular weight of the mixture is lowered during melt-kneading. Further, improvement in productivity has also been desired in that a long-time reaction is required in solid phase polymerization.
- the formation of the stereo complex is controlled only by the kneading temperature, and partial melting is observed during kneading, so that the crystal characteristics of the mixture are insufficient, and there are variations. Further, the polylactic acid block copolymer obtained by solid-phase polymerization of the kneaded product has a problem that crystal characteristics are insufficient.
- An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a method for producing a polylactic acid block copolymer that forms a polylactic acid stereocomplex having a high molecular weight and a high melting point.
- the method for producing a polylactic acid block copolymer of the present invention has a weight average molecular weight of one of poly-L-lactic acid and poly-D-lactic acid as a raw material of not less than 170,000, and the other weight average molecular weight. Is preferably 20,000 or more.
- the mixture of poly-L-lactic acid and poly-D-lactic acid preferably satisfies the following formula (2).
- the obtained polylactic acid block copolymer preferably satisfies the following formula (3).
- the polylactic acid block copolymer in the DSC measurement of the obtained polylactic acid block copolymer, the polylactic acid block copolymer is heated to 250 ° C. and kept at a constant temperature for 3 minutes, and then cooled. It is preferable that the temperature-falling crystallization temperature when the temperature is lowered at a rate of 20 ° C./min is 130 ° C. or higher.
- the degree of dispersion represented by the ratio of the weight average molecular weight to the number average molecular weight of the obtained polylactic acid block copolymer is 2.7 or less.
- the method for producing a polylactic acid block copolymer of the present invention is a molded article containing the resulting polylactic acid block copolymer, wherein the molded article satisfies the following formula (4) and has a thickness of 100 ⁇ m:
- the haze value is preferably 30% or less.
- Relative crystallinity [( ⁇ Hm ⁇ Hc) / ⁇ Hm] ⁇ 100> 90 (4)
- ⁇ Hm Crystal melting enthalpy (J / g) of the molded body
- ⁇ Hc Crystallization enthalpy at elevated temperature of the molded body (J / g)
- the catalyst contained in the mixture is preferably 0.001 to 0.5 parts by weight with respect to 100 parts by weight of the mixture.
- the catalyst contained in the mixture is obtained 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. It is preferable that it is at least one kind.
- the tin compound is at least one selected from tin (II) acetate, tin (II) octylate, tin (II) chloride, and tin (IV) chloride
- the sulfonic acid compound is preferably at least one selected from methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, propanedisulfonic acid, naphthalene disulfonic acid, and 2-aminoethanesulfonic acid.
- the temperature during solid-phase polymerization is preferably raised stepwise or continuously.
- the polylactic acid block copolymer to be obtained preferably has a weight average molecular weight of 100,000 or more.
- a polylactic acid block copolymer forming a polylactic acid stereocomplex having a high molecular weight and a high melting point can be produced in a high yield. Since this polylactic acid block copolymer has a high molecular weight and a high melting point, it can be suitably used in fields requiring heat resistance, which was difficult to use with polylactic acid homopolymers.
- the polylactic acid block copolymer is a polylactic acid block copolymer in which a segment composed of L-lactic acid units and a segment composed of D-lactic acid units are covalently bonded.
- the segment composed of L-lactic acid units is a polymer containing L-lactic acid as a main component, and means a polymer containing 70 mol% or more of L-lactic acid units. It is more preferably 80 mol% or more, more preferably 90 mol% or more, particularly preferably 95 mol% or more, and most preferably 98 mol% or more.
- the segment composed of D-lactic acid units is a polymer mainly composed of D-lactic acid and means a polymer containing 70 mol% or more of D-lactic acid units.
- the content is more preferably 80 mol% or more, more preferably 90 mol% or more, particularly preferably 95 mol% or more, and most preferably 98 mol% or more.
- the segment composed of L-lactic acid or D-lactic acid unit contains other components as long as the performance of the polylactic acid block copolymer and the polylactic acid resin composition containing the polylactic acid block copolymer is not impaired. Units may be included. Examples of component units other than L-lactic acid or D-lactic acid units include polycarboxylic acids, polyhydric alcohols, hydroxycarboxylic acids, and lactones.
- succinic acid adipic acid, sebacic acid
- Polycarboxylic acids such as fumaric acid, terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 5-sodium sulfoisophthalic acid, 5-tetrabutylphosphonium sulfoisophthalic acid or their derivatives, ethylene glycol, propylene glycol, butane Ethylene oxide or propylene oxide was added to diol, pentanediol, hexanediol, octanediol, neopentyl glycol, glycerin, trimethylolpropane, pentaerythritol, trimethylolpropane or pentaerythritol
- Polyhydric alcohols aromatic polyhydric alcohols obtained by addition reaction of ethylene oxide with bisphenol, polyhydric alcohols such as diethylene glycol, triethylene glycol, polyethylene glycol
- the weight average molecular weight of the polylactic acid block copolymer obtained by the method of the present invention is not particularly limited, but is preferably 100,000 or more and less than 300,000 from the viewpoint of mechanical properties. More preferably, it is 120,000 or more and less than 280,000, more preferably 130,000 or more and less than 270,000, particularly preferably 140,000 or more and less than 260,000 from the viewpoint of moldability and mechanical properties.
- the degree of dispersion of the polylactic acid block copolymer is preferably in the range of 1.5 to 3.0 from the viewpoint of mechanical properties. The range of the degree of dispersion is more preferably 1.8 to 2.7, and 2.0 to 2.4 is particularly preferable from the viewpoint of moldability and mechanical properties.
- the weight average molecular weight and dispersity are values in terms of standard polymethyl methacrylate as measured by gel permeation chromatography (GPC) using hexafluoroisopropanol or chloroform as a solvent.
- the polylactic acid block copolymer obtained in the present invention preferably has a stereocomplex formation rate (Sc) in the range of 80 to 100% from the viewpoint of heat resistance. More preferably, it is in the range of 85 to 100%, and particularly preferably 90 to 100%.
- the stereocomplex formation rate is the ratio of the stereocomplex crystals in all the crystals in polylactic acid. Specifically, poly-L-lactic acid single crystals and poly-D-lactic acid single crystals melted when heated from 30 ° C. to 250 ° C. with a differential scanning calorimeter (DSC) at a temperature rising rate of 20 ° C./min. It is possible to calculate by the following formula (3), where ⁇ Hl is the amount of heat based on ⁇ , and ⁇ Hh is the amount of heat based on crystal melting of the stereocomplex crystal.
- the total number of segments consisting of L-lactic acid units and segments consisting of D-lactic acid units contained in one molecule of the polylactic acid block copolymer is 3 or more. It is preferable in that a polylactic acid block copolymer that easily forms can be obtained. More preferably, it is 5 or more, and it is especially preferable that it is 7 or more.
- the total weight ratio of the segment composed of L-lactic acid units and the segment composed of D-lactic acid units is preferably 90:10 to 10:90. More preferably, it is 80:20 to 20:80, and particularly preferably 75:25 to 60:40 or 40:60 to 25:75.
- the weight ratio of the segment comprising L-lactic acid units is in the above preferred range, a polylactic acid stereocomplex is easily formed, and as a result, the rise in the melting point of the polylactic acid block copolymer is sufficiently large.
- the method for producing poly-L-lactic acid comprising L-lactic acid units and poly-D-lactic acid comprising D-lactic acid units used as raw materials is not particularly limited, and production of general polylactic acid is not limited.
- the method can be used. Specifically, using L-lactic acid or D-lactic acid as a raw material, a cyclic dimer L-lactide or D-lactide is once generated, and then ring-opening polymerization is performed.
- a one-step direct polymerization method in which a raw material is directly subjected to dehydration condensation in a solvent or a non-solvent is known, and any production method may be used.
- poly-L-lactic acid is a polymer containing L-lactic acid as a main component, and means a polymer containing 70 mol% or more of L-lactic acid units.
- the content is preferably 80 mol%, more preferably 90 mol% or more, still more preferably 95 mol% or more, and particularly preferably 98 mol% or more.
- Poly-D-lactic acid is a polymer mainly composed of D-lactic acid, and means a polymer containing 70 mol% or more of D-lactic acid units.
- the content is preferably 80 mol%, more preferably 90 mol% or more, still more preferably 95 mol% or more, and particularly preferably 98 mol% or more.
- the amount of lactide and oligomer contained in poly-L-lactic acid or poly-D-lactic acid is preferably 5% or less, respectively. More preferably, it is 3% or less, and particularly preferably 1% or less.
- the amount of lactic acid contained in poly-L-lactic acid or poly-D-lactic acid is preferably 2% or less. More preferably, it is 1% or less, Most preferably, it is 0.5% or less.
- the acid value of poly-L-lactic acid or poly-D-lactic acid is preferably 100 eq / ton in either one of poly-L-lactic acid or poly-D-lactic acid. More preferably, it is 50 eq / ton or less, More preferably, it is 30 eq / ton or less, Especially preferably, it is 15 eq / ton or less.
- the other acid value of poly-L-lactic acid or poly-D-lactic acid to be mixed is preferably 600 eq / ton or less. More preferably, it is 300 eq / ton or less, More preferably, it is 150 eq / ton or less, Most preferably, it is 100 eq / ton or less.
- One of the poly-L-lactic acid and poly-D-lactic acid used in the present invention has a weight average molecular weight of 60,000 to 300,000, and the other has a weight average molecular weight of 10,000 to 50,000. It is preferable. If the weight average molecular weight is less than 10,000, the polylactic acid block copolymer has a high degree of dispersion and the weight average molecular weight does not increase. On the other hand, if the weight average molecular weight exceeds 50,000, the polylactic acid block copolymer There is a problem that the formation rate of the stereocomplex becomes low. More preferably, one weight average molecular weight is 100,000 to 270,000 and the other weight average molecular weight is 15,000 to 45,000.
- one weight average molecular weight is 150,000 to 240,000 and the other weight average molecular weight is 20,000 to 40,000.
- the combination of the weight average molecular weights of poly-L-lactic acid and poly-D-lactic acid is preferably selected as appropriate so that the weight average molecular weight after mixing is 90,000 or more.
- the ratio of the higher weight average molecular weight to the lower weight average molecular weight of the poly-L-lactic acid and poly-D-lactic acid used in the present invention is preferably 2 or more and less than 30. If this ratio is less than 2, there is a problem that the stereocomplex formation rate of the polylactic acid block copolymer is lowered. On the other hand, if this ratio is 30 or more, the degree of dispersion of the polylactic acid block copolymer increases, There is a problem that physical properties are lowered. More preferably, it is 3 or more and less than 20, and more preferably 5 or more and less than 15.
- Examples of the polymerization catalyst for producing poly-L-lactic acid or poly-D-lactic acid by the ring-opening polymerization method include a metal catalyst and an acid catalyst.
- Examples of the metal catalyst include tin catalysts, titanium compounds, lead compounds, zinc compounds, cobalt compounds, iron compounds, lithium compounds, and rare earth compounds.
- As the kind of the compound metal alkoxide, metal halogen compound, organic carboxylate, carbonate, sulfate, oxide and the like are preferable.
- 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 acetate (II), tin acetate (IV), tin octylate (II), 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 t
- Titanium compounds lead diisopropoxy (II), lead monochloride, lead acetate, lead (II) octylate, lead (II) isooctanoate, lead (II) isononanoate, lead (II) laurate, lead oleate
- Lead compounds such as (II), lead linoleate (II), lead naphthenate, lead neodecanoate (II), 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, cobalt chloride, cobalt acetate, cobalt octylate (II), isooctane Cobalt (II), cobalt (II) isononanoate, cobalt (II) laurate, cobal
- potassium compounds such as potassium isopropoxide, potassium chloride, potassium acetate, potassium octylate, potassium naphthenate, t-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 ) And other
- the acid catalyst may be a Bronsted acid as a proton donor, a Lewis acid as an electron pair acceptor, or an organic acid or an inorganic acid.
- 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
- dicarboxylic acid compounds such as malonic acid, tricarboxylic acid compounds such as citric acid and tricarivallic acid, benzenesulfonic acid, n-butylbenzenesulfonic acid, n-octylbenzenesulfonic acid, n-dodecylbenzenesulfonic acid, pentadecylbenzenesulfonic acid 2,5-dimethylbenzenesulfonic acid, 2,5-dibutylbenzenesulfonic acid, o-aminobenzenesulf
- 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.
- 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 complexes 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.
- a metal catalyst is preferred as the polymerization catalyst, among which tin compounds, titanium compounds, antimony compounds, and rare earth compounds are more preferred, and when the melting point of the produced polylactic acid is taken into consideration More preferred are tin compounds and titanium compounds.
- tin-based organic carboxylates or tin-based halogen compounds are preferred, and in particular, tin (II) acetate, tin (II) octylate, and tin chloride (II) ) Is more preferable.
- the addition amount of the polymerization catalyst is not particularly limited, and is preferably 0.001 part by weight or more and 2 parts by weight or less with respect to 100 parts by weight of the raw material to be used (L-lactic acid, D-lactic acid, etc.). More preferred is 0.001 part by weight or more and 1 part by weight or less.
- the catalyst amount is within the above preferred range, an effect of shortening the polymerization time can be obtained, while the molecular weight of the finally obtained polylactic acid block copolymer tends to increase.
- the addition timing of the polymerization catalyst is not particularly limited, but it is preferable to add the catalyst after heating and dissolving the lactide from the viewpoint of uniformly dispersing the catalyst in the system and increasing the polymerization activity.
- a metal catalyst and an acid catalyst can be mentioned.
- Preferred metal catalysts include tin compounds, titanium compounds, lead compounds, zinc compounds, cobalt compounds, iron compounds, lithium compounds, rare earth compounds, and types of compounds include metal alkoxides, metal halogen compounds, and organic carboxylates. Carbonate, sulfate, oxide and the like are preferable.
- 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 acetate (II), tin acetate (IV), tin octylate (II), 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 t
- Titanium compounds lead diisopropoxy (II), lead monochloride, lead acetate, lead (II) octylate, lead (II) isooctanoate, lead (II) isononanoate, lead (II) laurate, lead oleate
- Lead compounds such as (II), lead linoleate (II), lead naphthenate, lead neodecanoate (II), 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, cobalt chloride, cobalt acetate, cobalt octylate (II), isooctane Cobalt (II), cobalt (II) isononanoate, cobalt (II) laurate, cobal
- potassium compounds such as potassium isopropoxide, potassium chloride, potassium acetate, potassium octylate, potassium naphthenate, t-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 ) And other
- a preferred acid catalyst may be a Bronsted acid as a proton donor, a Lewis acid as an electron pair acceptor, or an organic acid or an inorganic acid.
- 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
- dicarboxylic acid compounds such as malonic acid, tricarboxylic acid compounds such as citric acid and tricarivallic acid, benzenesulfonic acid, n-butylbenzenesulfonic acid, n-octylbenzenesulfonic acid, n-dodecylbenzenesulfonic acid, pentadecylbenzenesulfonic acid 2,5-dimethylbenzenesulfonic acid, 2,5-dibutylbenzenesulfonic acid, o-aminobenzenesulf
- 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.
- 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 complexes 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.
- tin compounds when considering the molecular weight of the produced polylactic acid, tin compounds, titanium compounds, antimony compounds, rare earth compounds, and acid catalysts are preferred, and when considering the melting point of the produced polylactic acid, tin compounds, titanium compounds are preferred. And sulfonic acid compounds are more preferred.
- a tin-based organic carboxylate or a tin-based halogen compound is preferable, particularly tin (II) acetate, tin (II) octylate
- mono and disulfonic acid compounds are preferred, methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, propanedisulfonic acid, naphthalene disulfonic acid, and 2-aminoethane Sulphonic acid is more preferred.
- one type of catalyst may be used, or two or more types may be used in combination, but it is preferable to use two or more types in combination from the viewpoint of increasing the polymerization activity. It is preferable to use one or more selected from tin compounds and / or one or more selected from sulfonic acid compounds from the viewpoint that coloring can be suppressed.
- tin acetate (II) and / or tin (II) octylate and any one of methanesulfonic acid, ethanesulfonic acid, propanedisulfonic acid, naphthalenedisulfonic acid, and 2-aminoethanesulfonic acid More preferably, it is used in combination with one or more kinds of tin (II) acetate and / or tin (II) octylate and any one of methanesulfonic acid, ethanesulfonic acid, propanedisulfonic acid and 2-aminoethanesulfonic acid. The combined use is more preferable.
- the addition amount of the polymerization catalyst is not particularly limited, and is preferably 0.001 part by weight or more and 0.5 part by weight or less with respect to 100 parts by weight of the raw material to be used (L-lactic acid, D-lactic acid, etc.) In particular, 0.001 part by weight or more and 0.3 part by weight or less are more preferable.
- the catalyst amount is within the above preferred range, an effect of shortening the polymerization time can be obtained, while the molecular weight of the finally obtained polylactic acid block copolymer tends to increase.
- tin When one or more types selected from tin compounds and / or one or more types selected from sulfonic acid compounds are used in combination, tin can be maintained because high polymerization activity can be maintained and coloring can be suppressed.
- the weight ratio of the compound to the sulfonic acid compound is preferably 1: 1 to 1:30. In view of excellent productivity, the weight ratio of the tin compound and the sulfonic acid compound is more preferably 1: 2 to 1:15.
- the addition timing of the polymerization catalyst is not particularly limited, but the acid catalyst is preferably added after dehydrating the raw material or the raw material in terms of excellent productivity, and the metal catalyst is added after dehydrating the raw material. It is preferable in view of increasing the polymerization activity.
- Polylactic acid mixing method Next, the process of mixing poly-L-lactic acid and poly-D-lactic acid will be described.
- poly-L-lactic acid and poly-D-lactic acid are mixed to form a mixture in which the stereocomplex formation rate (Sc) is in the range of more than 60% to 100% immediately before solid-phase polymerization. It is important to polymerize.
- the stereocomplex formation rate (Sc) of the mixture is preferably in the range of more than 70% to 99%, particularly preferably in the range of more than 80% to 95%.
- the stereocomplex formation rate is the ratio of the stereocomplex crystals in all the crystals in polylactic acid. Specifically, poly-L-lactic acid single crystal and poly-D-lactic acid single crystal when heated from 30 ° C. to 250 ° C.
- the crystallization treatment temperature here is higher than the glass transition temperature and is lower than the melting point of polylactic acid having a low melting point among the poly-L-lactic acid or poly-D-lactic acid mixed as described above. Although not particularly limited, it is more preferable that the temperature is within the range of the temperature rising crystallization temperature and the temperature falling crystallization temperature measured in advance by a differential scanning calorimeter (DSC).
- DSC differential scanning calorimeter
- any of reduced pressure, normal pressure, and increased pressure may be used.
- the time for crystallization is not particularly limited, but it is sufficiently crystallized within 3 hours, and within 2 hours is preferable.
- the method for mixing poly-L-lactic acid and poly-D-lactic acid is not particularly limited.
- the melting point of the higher melting point component of poly-L-lactic acid and poly-D-lactic acid is higher than the melting end temperature.
- the method include melt kneading and a method of removing the solvent after mixing in a solvent, but from the viewpoint of efficient mixing, a method of melt kneading at or above the melting end temperature is preferable.
- the melting point refers to the temperature at the top of the polylactic acid single crystal melting peak measured by (DSC) with a differential scanning calorimeter, and the melting end temperature is determined with a differential scanning calorimeter (DSC). It means the peak end temperature in the polylactic acid single crystal melting peak measured by the above.
- Examples of the method of melt kneading at a temperature higher than the melting end temperature include a method in which poly-L-lactic acid and poly-D-lactic acid are mixed by a batch method or a continuous method.
- Examples include a single screw extruder, a twin screw extruder, a plast mill, a kneader, and a stirred tank reactor equipped with a pressure reducing device. From the viewpoint of uniform and sufficient kneading, a single screw extruder or a twin screw extruder may be used. preferable.
- the method for supplying polylactic acid is not particularly limited.
- a method for supplying poly-L-lactic acid and poly-D-lactic acid in a lump from a resin supply port, and a side supply port as required. Can be used to supply poly-L-lactic acid and poly-D-lactic acid separately to the resin supply port and the side supply port, respectively.
- the supply of polylactic acid to the kneader can also be performed in a molten state directly from the polylactic acid production process.
- the screw element in the extruder is preferably provided with a kneading element in the mixing part so that poly-L-lactic acid and poly-D-lactic acid can be uniformly mixed to form a stereo complex.
- the mixing is performed at a temperature higher than the melting end temperature of the component having a higher melting point among poly-L-lactic acid and poly-D-lactic acid.
- the range is preferably 140 ° C to 250 ° C, more preferably 160 ° C to 230 ° C, and particularly preferably 180 ° C to 210 ° C.
- the mixing time condition is preferably in the range of 0.1 to 10 minutes, more preferably in the range of 0.3 to 5 minutes, and particularly preferably in the range of 0.5 to 3 minutes.
- the mixing time is in the above preferred range, poly-L-lactic acid and poly-D-lactic acid can be uniformly mixed, and thermal decomposition is hardly caused by mixing.
- the pressure condition for mixing is not particularly limited, and may be any condition under an air atmosphere or an inert gas atmosphere such as nitrogen.
- the mixing weight ratio of poly-L-lactic acid composed of L-lactic acid units and poly-D-lactic acid composed of D-lactic acid units is preferably 90:10 to 10:90. More preferably, it is 80:20 to 20:80, and particularly preferably 75:25 to 40:60 or 40:60 to 25:75.
- the weight ratio of poly-L-lactic acid composed of L-lactic acid units is within the above preferred range, the melting point of the finally obtained polylactic acid block copolymer is increased, while a polylactic acid stereocomplex is formed. It becomes easy.
- the mixing weight ratio of poly-L-lactic acid and poly-D-lactic acid is other than 50:50, it is preferable to add a larger amount of poly-L-lactic acid or poly-D-lactic acid having a larger weight average molecular weight. .
- the catalyst may be a residual amount of the catalyst in producing poly-L-lactic acid and / or poly-D-lactic acid, or one or more selected from the above catalysts may be added in the mixing step. it can.
- the content of the catalyst is not particularly limited, and is preferably 0.001 part by weight or more and 0.5 part by weight or less with respect to 100 parts by weight of the mixture of poly-L-lactic acid and poly-D-lactic acid. 0.001 part by weight or more and 0.3 part by weight or less are more preferable.
- the catalyst amount is within the above preferred range, an effect of shortening the polymerization time can be obtained, while the molecular weight of the finally obtained polylactic acid block copolymer tends to increase.
- poly-L-lactic acid (segment consisting of L-lactic acid units) composed of L-lactic acid units of the polylactic acid block copolymer finally obtained within a range not impairing the effects of the present invention
- a polyfunctional compound may be mixed.
- the polyfunctional compound used here is not particularly limited, and polyvalent carboxylic acid anhydride, polyvalent carboxylic acid halide, polyvalent carboxylic acid, polyvalent isocyanate, polyvalent amine, polyhydric alcohol and Polyepoxy compounds and the like, specifically, 1,2-cyclohexanedicarboxylic anhydride, succinic anhydride, phthalic anhydride, trimellitic anhydride, 1,8-naphthalenedicarboxylic anhydride, Polycarboxylic acid anhydrides such as pyromellitic acid anhydride, polycarboxylic acid halides such as isophthalic acid chloride, terephthalic acid chloride, 2,6-naphthalenedicarboxylic acid chloride, succinic acid, adipic acid, sebacic acid, fumaric acid , Terephthalic acid, isophthalic acid, polyvalent carboxylic acids such as 2,6-naphthalenedicarboxylic acid, hexamethyle Polyisocyanates
- polyvalent carboxylic acid anhydrides Preferred are polyvalent carboxylic acid anhydrides, polyvalent isocyanates, polyhydric alcohols and polyvalent epoxy compounds, and particularly preferred are polyvalent carboxylic acid anhydrides, polyvalent isocyanates and polyvalent epoxy compounds. These can be used alone or in combination of two or more.
- the mixing amount of the polyfunctional compound is not particularly limited, and is preferably 0.01 parts by weight or more and 20 parts by weight or less with respect to 100 parts by weight of the total of poly-L-lactic acid and poly-D-lactic acid. Further, it is more preferably 0.1 parts by weight or more and 10 parts by weight or less.
- the effect which uses a polyfunctional compound can be exhibited as the addition amount of a polyfunctional compound is the said preferable range.
- a reaction catalyst may be added in order to promote the reaction of poly-L-lactic acid and poly-D-lactic acid with the polyfunctional compound.
- the reaction catalyst include sodium hydroxide, potassium hydroxide, lithium hydroxide, cesium hydroxide, sodium hydrogen carbonate, potassium hydrogen carbonate, sodium carbonate, potassium carbonate, lithium carbonate, sodium acetate, potassium acetate, lithium acetate, stearin.
- Alkali metal compounds such as dipotassium, dilithium hydrogen phosphate, disodium salt of bisphenol A, dipotassium salt, dilithium salt, sodium salt of phenol, potassium salt, lithium salt, cesium salt, hydroxide Calcium, hydroxide Alkaline earths such as lithium, magnesium hydroxide, strontium hydroxide, calcium bicarbonate, barium carbonate, magnesium carbonate, strontium carbonate, calcium acetate, barium acetate, magnesium acetate, strontium acetate, calcium stearate, magnesium stearate, strontium stearate Metal compounds, triethylamine, tributylamine, trihexylamine, triamylamine, triethanolamine, dimethylamino
- the addition amount of the reaction catalyst is not particularly limited, and is preferably 0.001 part by weight or more and 0.5 part by weight or less with respect to 100 parts by weight of the total of poly-L-lactic acid and poly-D-lactic acid.
- the catalyst amount is within the above preferred range, the effect of shortening the polymerization time can be obtained, while the molecular weight of the finally obtained polylactic acid block copolymer can be increased.
- the weight average molecular weight (Mw) of the mixture of poly-L-lactic acid and poly-D-lactic acid after mixing needs to be 90,000 or more from the viewpoint of improving the yield after solid-phase polymerization.
- Mw is less than 90,000, the yield after solid-phase polymerization becomes low, and there is a problem that productivity is inferior. 100,000 or more is more preferable, 110,000 or more is more preferable, and 120,000 or more is particularly preferable.
- the yield after solid-phase polymerization is the ratio of the weight of the polylactic acid block copolymer after solid-phase polymerization to the weight of the mixture before solid-phase polymerization. Specifically, when the weight of the mixture before solid phase polymerization is Wp and the weight of the polymer after solid phase polymerization is Ws, it can be calculated by the following formula (5).
- the dispersion degree of the mixture of poly-L-lactic acid and poly-D-lactic acid after mixing is preferably in the range of 1.5 to 4.0. A more preferred range is 2.0 to 3.7, and a particularly preferred range is 2.5 to 3.5.
- the degree of dispersion means the ratio of the weight average molecular weight to the number average molecular weight of the mixture.
- the standard polydispersity by gel permeation chromatography (GPC) measurement using hexafluoroisopropanol or chloroform as a solvent It is a value in terms of methyl methacrylate.
- the amount of lactide and the amount of oligomer contained in poly-L-lactic acid or poly-D-lactic acid are each preferably 5% or less. More preferably, it is 3% or less, and particularly preferably 1% or less.
- the amount of lactic acid contained in poly-L-lactic acid or poly-D-lactic acid is preferably 2% or less. More preferably, it is 1% or less, and particularly preferably 0.5% or less.
- the shape of the mixture of poly-L-lactic acid and poly-D-lactic acid is not particularly limited, and any of a lump, a film, a pellet, and a powder may be used. From the viewpoint of efficiently proceeding with solid phase polymerization, it is preferable to use pellets or powder.
- the method for forming pellets include a method in which the mixture is extruded into a strand shape and pelletized, and a method in which the mixture is extruded into water and pelletized using an underwater cutter.
- pulverizing using grinders such as a mixer, a blender, a ball mill, and a hammer mill, is mentioned.
- the method for carrying out this solid phase polymerization step is not particularly limited, and may be a batch method or a continuous method.
- the reaction vessel may be a stirred tank reactor, a mixer reactor, a tower reactor, or the like. These reactors can be used in combination of two or more.
- a mixture of poly-L-lactic acid and poly-D-lactic acid is crystallized.
- the poly-L-lactic acid and the poly-D are used during the solid phase polymerization step. -Crystallization of the mixture of lactic acid is not necessarily required, but the efficiency of solid phase polymerization can be further increased by crystallization.
- the method for crystallization is not particularly limited, and a known method can be used. Examples thereof include a method of maintaining the crystallization treatment temperature in a gas phase or a liquid phase, and a method of cooling and solidifying a molten mixture of poly-L-lactic acid and poly-D-lactic acid while performing stretching or shearing operations. From the viewpoint that the operation is simple, a method of holding at the crystallization treatment temperature in the gas phase or in the liquid phase is preferable.
- the crystallization treatment temperature here is higher than the glass transition temperature and is lower than the melting point of polylactic acid having a low melting point among the poly-L-lactic acid or poly-D-lactic acid mixed as described above. Although not particularly limited, it is more preferable that the temperature is within the range of the temperature rising crystallization temperature and the temperature falling crystallization temperature measured in advance by a differential scanning calorimeter (DSC).
- DSC differential scanning calorimeter
- any of reduced pressure, normal pressure, and increased pressure may be used.
- the time for crystallization is not particularly limited, but it is sufficiently crystallized within 3 hours, and within 2 hours is preferable.
- the temperature condition for carrying out this solid phase polymerization step is a temperature not higher than the melting point of the mixture of poly-L-lactic acid and poly-D-lactic acid, and specifically, preferably 100 ° C. or higher and 220 ° C. or lower. Further, from the viewpoint of further promoting solid phase polymerization, it is more preferably 110 ° C. or more and 210 ° C. or less, and most preferably 120 ° C. or more and 200 ° C. or less.
- the melting point of the mixture of poly-L-lactic acid and poly-D-lactic acid is measured by a differential scanning calorimeter (DSC) when the temperature is increased from 30 ° C. to 250 ° C. at a temperature increase rate of 20 ° C./min.
- DSC differential scanning calorimeter
- the temperature conditions when the temperature is raised stepwise during solid-phase polymerization are as follows: 120 to 145 ° C. for 1 to 15 hours as the first stage, 135 to 160 ° C. for 1 to 15 hours as the second stage, and 150 as the third stage. It is preferable to raise the temperature at ⁇ 175 ° C. for 10 to 30 hours. Further, as the first step, it is 130 to 145 ° C. for 2 to 12 hours, as the second step, 140 to 160 ° C. for 2 to 12 hours, as the third step. It is more preferable to raise the temperature at 155 to 175 ° C. for 10 to 25 hours.
- a temperature condition for continuously raising the temperature during solid phase polymerization it is preferable to continuously raise the temperature from an initial temperature of 130 ° C. to 150 ° C. to 150 to 175 ° C. at a rate of 1 to 5 ° C./min.
- combining stepwise temperature rise and continuous temperature rise is also preferable from the viewpoint of efficiently proceeding solid phase polymerization.
- this solid phase polymerization step when carried out, it is preferably carried out under reduced pressure or in an inert gas stream such as dry nitrogen.
- the degree of vacuum when performing solid-phase polymerization under reduced pressure is preferably 150 Pa or less, more preferably 75 Pa or less, and particularly preferably 20 Pa or less.
- the flow rate of the inert gas when solid-phase polymerization is performed under an inert gas stream is preferably in the range of 0.1 to 2,000 mL / min, and in the range of 0.5 to 1,000 mL / min with respect to 1 g of the mixture. Is more preferable, and the range of 1.0 to 500 mL / min is particularly preferable.
- the polymer yield after solid phase polymerization is preferably 90% or more. More preferably, it is 93% or more, and particularly preferably 95% or more.
- the polymer yield here is the ratio of the weight of the polylactic acid block copolymer after solid phase polymerization to the weight of the mixture before solid phase polymerization. Specifically, when the weight of the mixture before solid phase polymerization is Wp and the weight of the polymer after solid phase polymerization is Ws, it can be calculated by the following formula (6).
- the degree of dispersion of the mixture is small. Specifically, the dispersion degree of the mixture before the solid phase polymerization is in the range of 1.5 to 4.0, and the dispersion degree of the polylactic acid block copolymer is in the range of 1.5 to 2.7 after the solid phase polymerization. It is preferable. More preferably, the dispersion degree of the mixture before the solid phase polymerization is in the range of 2.0 to 3.7, and the dispersion degree of the polylactic acid block copolymer is reduced to the range of 1.8 to 2.6 after the solid phase polymerization.
- the degree of dispersion of the polylactic acid block copolymer is 2.0 to 2.5 after the solid phase polymerization from the range of the dispersion degree of the mixture before the solid phase polymerization of 2.5 to 3.5. It is to be in the range.
- the weight average molecular weight of the polylactic acid block copolymer obtained by the production method of the present invention is not particularly limited, but is preferably in the range of 100,000 or more and less than 300,000 in terms of moldability and mechanical properties. . More preferably, it is in the range of 120,000 or more and less than 280,000, and particularly preferably in the range of 140,000 or more and less than 260,000.
- the degree of dispersion of the polylactic acid block copolymer is preferably in the range of 1.5 to 3.0 from the viewpoint of mechanical properties.
- the range of the degree of dispersion is more preferably 1.8 to 2.7, and 2.0 to 2.4 is particularly preferable from the viewpoints of moldability and mechanical properties.
- the weight average molecular weight and dispersity are values in terms of standard polymethyl methacrylate as measured by gel permeation chromatography (GPC) using hexafluoroisopropanol or chloroform as a solvent.
- the average chain length of the polylactic acid block copolymer obtained by the production method of the present invention is preferably 20 or more. More preferably, it is 25 or more, and 30 or more is particularly preferable from the viewpoint of mechanical properties of the molded article.
- the average chain length of the compact was determined by 13 C-NMR measurement, and the integrated value of the peak existing in the vicinity of 170.1 to 170.3 ppm of the carbon peak attributed to carbonyl carbon was (169). When the integrated value of the peak existing in the vicinity of 8 to 170.0 ppm is (b), it can be calculated by the following formula (7).
- the polylactic acid block copolymer obtained by the production method of the present invention has a melting point based on poly-L-lactic acid single crystals and poly-D-lactic acid single crystals in the range of 150 ° C. to 190 ° C., and is a stereocomplex.
- the formation has a melting point based on stereocomplex crystals in the range of 200-230 ° C.
- a preferable range of the melting point derived from the stereocomplex crystal is 205 ° C. to 230 ° C., a temperature range of 210 ° C. to 230 ° C. is more preferable, and a temperature range of 215 ° C. to 230 ° C. is particularly preferable.
- the crystallinity can be controlled by the amount of the main L-lactic acid (or D-lactic acid) unit contained in the poly-L-lactic acid (or poly-D-lactic acid) used as a raw material.
- the melting point derived from the stereocomplex crystal is preferably increased.
- the preferred range of the main component L-lactic acid contained in poly-L-lactic acid is preferably 80 mol%, more preferably 90 mol% or more, and more preferably 95 mol% or more. More preferably, it is more preferably 98 mol% or more.
- the polylactic acid block copolymer preferably has a stereocomplex formation rate (Sc) in the range of 80 to 100% from the viewpoint of heat resistance. More preferably, it is in the range of 85 to 100%, and particularly preferably 90 to 100%.
- the stereocomplex formation rate is the ratio of the stereocomplex crystals in all the crystals in polylactic acid. Specifically, the crystal melting of poly-L-lactic acid single crystal and poly-D-lactic acid single crystal when the temperature is increased from 30 ° C. to 250 ° C. at a temperature rising rate of 20 ° C./min with a differential scanning calorimeter (DSC). It is possible to calculate by the following formula (8), where ⁇ H1 is the amount of heat based on and ⁇ Hh is the amount of heat based on crystal melting of the stereocomplex crystal.
- the polylactic acid block copolymer obtained by the production method of the present invention preferably has a temperature-falling crystallization temperature (Tc) of 130 ° C. or higher in terms of excellent moldability and heat resistance.
- Tc temperature-falling crystallization temperature
- the temperature drop crystallization temperature (Tc) of the molded body is a constant temperature state at 250 ° C. for 3 minutes after being heated from 30 ° C. to 250 ° C. by a differential scanning calorimeter (DSC) at a temperature rising rate of 20 ° C./min.
- DSC differential scanning calorimeter
- the crystallization temperature derived from polylactic acid crystals measured when the temperature was lowered at a cooling rate of 20 ° C./min.
- the crystallization temperature (Tc) is not particularly limited, but is preferably 130 ° C. or higher, more preferably 132 ° C. or higher, and particularly preferably 135 ° C. or higher from the viewpoint of heat resistance and transparency.
- the polylactic acid block copolymer has a high melting point due to the formation of a polylactic acid stereocomplex that the total number of segments consisting of L-lactic acid units and segments consisting of D-lactic acid units contained in one molecule is 3 or more. It is preferable in terms of easy.
- the polylactic acid block copolymer obtained according to the present invention after solid-phase polymerization.
- 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 used 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. Further preferred examples of specific examples include “ADEKA STAB” AX-71 (dioftademil phosphate), PEP-8 (distearyl pentaerythritol diphosphite), PEP-36 (cyclic neopentatetrayl bis) manufactured by ADEKA Corporation. (2,6-tert-butyl-4-methylphenyl) phosphite).
- hindered phenol compounds include n-octadecyl-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) -propionate, n-octadecyl-3- (3′-methyl).
- hindered phenol compounds include “ADEKA STAB” AO-20, AO-30, AO-40, AO-50, AO-60, AO-70, AO-80, manufactured by ADEKA Corporation.
- AO-330 “Irganox” 245,259,565,1010,1035,1076,1098,1222,1330,1425,1520,3114,5057, manufactured by Ciba Specialty Chemicals Co., Ltd., manufactured by Sumitomo Chemical Co., Ltd.
- thioether compound examples 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).
- thioether compounds include “ADEKA STAB” A0-23, AO-412S, AO-503A manufactured by ADEKA Corporation, “Irganox” PS802 manufactured by Ciba Specialty Chemicals Co., Ltd., Sumitomo Chemical Industries, Ltd. "Sumilyzer” TPL-R, TPM, TPS, TP-D, DSTP, DLTP, DLTOIB, DMTP manufactured by API Corporation, "Sinox” 412S, manufactured by Cypro Kasei Co., Ltd. " Cyanox "1212 etc. are mentioned.
- polyamine compounds include 3,9-bis [2- (3,5-diamino-2,4,6-triazaphenyl) ethyl] -2,4,8,10-tetraoxaspiro.
- Undecane ethylenediamine-tetraacetic acid, ethylenediamine-tetraacetic acid alkali metal salt (Li, Na, K), 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.
- hydrazine derivative compounds include decamethylene dicarboxylic acid-bis (N'-salicyloyl hydrazide), bis (2-phenoxypropionyl hydrazide) isophthalate, and N-formyl-N'-salicyloyl hydrazine.
- Examples of phosphorus compounds include phosphite compounds and phosphate compounds.
- Specific examples of such phosphite compounds include tetrakis [2-tert-butyl-4-thio (2′-methyl-4′-hydroxy-5′-tert-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-tert-butyl-4-thio (2'-methyl-4'-hydroxy-) 5'-tert-butylphenyl) -5-methylphenyl] -1
- Phosphite tetrakis (2,4-di-t-butylphenyl) 4,4'-biphenylenephosphonite, 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 (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.
- phosphite compounds include “ADEKA STAB” C, PEP-4C, PEP-8, PEP-11C, PEP-24G, PEP-36, HP-10, 2112, 260 manufactured by ADEKA Corporation. 522A, 329A, 1178, 1500, C, 135A, 3010, TPP, “Irgaphos” 168 manufactured by Ciba Specialty Chemicals Co., Ltd., “Smilizer” P-16 manufactured by Sumitomo Chemical Co., Ltd., “Sand” manufactured by Clariant Examples include stub “PEPQ” and “Weston” 618, 619G, and 624 manufactured by GE.
- the phosphate compound examples 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 manufactured by Ciba Specialty Chemicals Co., Ltd., “Inhibitor” OABH manufactured by Eastman Kodak Co., Ltd., “Adeka Stub” CDA-1, manufactured by ADEKA Corporation, CDA-6, AX-71 and the like 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 adding the catalyst deactivator is not particularly limited, and any of the polylactic acid production process, the polylactic acid mixing process and the solid phase polymerization process may be used, but a high melting point, high molecular weight polylactic acid block copolymer can be obtained.
- ordinary additives such as fillers (glass fiber, carbon fiber, metal fiber, natural fiber, organic fiber are used as long as the object of the present invention is not impaired.
- fillers glass fiber, carbon fiber, metal fiber, natural fiber, organic fiber
- the polylactic acid block copolymer obtained by the production method of the present invention includes other thermoplastic resins (for example, polyethylene, polypropylene, polystyrene, acrylic resin, acrylonitrile-butadiene, Styrene copolymer, polyamide, polycarbonate, polyphenylene sulfide resin, polyether ether ketone resin, polyester, polysulfone, polyphenylene oxide, polyacetal, polyimide, polyetherimide, cellulose ester, etc.) or thermosetting resin (eg phenol resin, melamine) Resin, polyester resin, silicone resin, epoxy resin, etc.) or soft thermoplastic resin (eg, ethylene / glycidyl methacrylate copolymer, polyester elastomer, De elastomers, ethylene / propylene terpolymer, ethylene / butene-1 copolymer) can further contain at least one or more of such.
- thermoplastic resins for example, polyethylene, polypropylene,
- an acrylic resin having an alkyl (meth) acrylate unit having an alkyl group having 1 to 4 carbon atoms as a main component is preferably mentioned. Further, alkyl (meth) acrylate having an alkyl group having 1 to 4 carbon atoms may be copolymerized with another alkyl acrylate having an alkyl group having 1 to 4 carbon atoms or an aromatic vinyl compound such as styrene. Good.
- alkyl (meth) acrylates having the above alkyl groups include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, cyclohexyl acrylate and cyclohexyl methacrylate.
- acrylic resin when the acrylic resin is used in the present invention, polymethyl methacrylate composed of methyl methacrylate is particularly preferable.
- the polylactic acid block copolymer obtained by the production method of the present invention has a characteristic that it easily forms a high-melting polylactic acid stereocomplex even after it is once melted and solidified when it is processed into a molded product.
- the haze value is preferably 30% or less.
- Relative crystallinity [( ⁇ Hm ⁇ Hc) / ⁇ Hm] ⁇ 100> 90 (9)
- ⁇ Hm is the crystal melting enthalpy (J / g) of the molded body
- ⁇ Hc is the crystallization enthalpy (J / g) of the molded body at elevated temperature.
- the relative crystallinity is preferably more than 90%, more preferably 92% or more, and particularly preferably 94% or more.
- ⁇ Hc is the crystallization enthalpy of the molded body measured by a differential scanning calorimeter (DSC) at a temperature rising rate of 20 ° C./min
- ⁇ Hm is measured by DSC at a temperature rising rate of 20 ° C./min.
- DSC differential scanning calorimeter
- the haze value is a value obtained by measuring a molded product having a thickness of 100 ⁇ m according to JIS K 7105. From the viewpoint of transparency, the haze value is preferably 30% or less, more preferably 10% or less. preferable. Although a minimum is not specifically limited, If it is 0.1% or more, it can be used practically without a problem.
- a molded body containing the obtained polylactic acid block copolymer having a relative crystallinity of over 90% and a thickness of 500 ⁇ m.
- the haze value is preferably 30% or less.
- the haze value is preferably 20% or less, more preferably 15% or less, further preferably 10% or less, further preferably 7% or less, and preferably 5% or less. It is particularly preferable in terms of sex.
- the lower limit is not particularly limited and is 0% or more.
- the molded product containing the obtained polylactic acid block copolymer does not contain a crystal nucleating agent used for improving transparency.
- the haze value is 30% or less when the relative crystallinity exceeds 90% or more and the molded product has a thickness of 1 mm.
- the haze value is preferably 20% or less, more preferably 15% or less, further preferably 10% or less, further preferably 7% or less, and preferably 5% or less. It is particularly preferable in terms of sex.
- the molded product containing the obtained polylactic acid block copolymer is excellent in moldability and heat resistance, so that the polylactic acid block copolymer contained in the molded product is
- the lowering crystallization temperature (Tc) is preferably 130 ° C. or higher.
- the temperature drop crystallization temperature (Tc) of the molded body is a constant temperature state at 250 ° C. for 3 minutes after being heated from 30 ° C. to 250 ° C. by a differential scanning calorimeter (DSC) at a temperature rising rate of 20 ° C./min.
- the crystallization temperature (Tc) is not particularly limited, but is preferably 130 ° C. or higher, more preferably 132 ° C. or higher, and particularly preferably 135 ° C. or higher from the viewpoint of heat resistance and transparency.
- the stereocomplex formation rate (Sc) is preferably 80% or more, and preferably 70% or more. More preferably, it is 75 to 100%, more preferably 90 to 100%.
- the stereocomplex formation rate is the ratio of the stereocomplex crystals in all the crystals in polylactic acid. Specifically, the amount of heat based on crystal melting of poly-L-lactic acid single crystal and poly-D-lactic acid single crystal measured by a differential scanning calorimeter (DSC) is ⁇ Hl, and the amount of heat based on crystal melting of stereocomplex crystals. Can be calculated by the following equation (10).
- the polylactic acid block copolymer contained in the molded product containing the polylactic acid block copolymer obtained in the present invention includes a segment composed of L-lactic acid units and a D-lactic acid unit contained per molecule of the polylactic acid block copolymer. It is preferable that the total number of the segments consisting of 3 is 3 or more in that a polylactic acid block copolymer that easily forms a polylactic acid stereocomplex having a high melting point can be obtained.
- the molecular weight per segment is preferably 2,000 to 50,000. More preferably, it is 4,000 to 45,000, and 5,000 to 40,000 is particularly preferable from the viewpoint of mechanical properties.
- the average chain length of the polylactic acid block copolymer contained in the molded product containing the polylactic acid block copolymer obtained in the present invention is preferably 20 or more. More preferably, it is 25 or more, and 30 or more is particularly preferable from the viewpoint of mechanical properties of the molded article.
- the average chain length of the compact was determined by 13 C-NMR measurement, and the integrated value of the peak existing in the vicinity of 170.1 to 170.3 ppm of the carbon peak attributed to carbonyl carbon was (169). When the integrated value of the peak existing in the vicinity of 8 to 170.0 ppm is (b), it can be calculated by the following formula (11).
- the weight average molecular weight of the polylactic acid block copolymer contained in the molded product containing the polylactic acid block copolymer obtained is not particularly limited, In terms of mechanical properties, it is preferably 100,000 or more and less than 300,000. More preferably, it is 120,000 or more and less than 280,000, and it is particularly preferably 140,000 or more and less than 260,000 in terms of moldability and mechanical properties.
- the dispersity of the polylactic acid block copolymer contained in the molded product containing the polylactic acid block copolymer obtained in the present invention is preferably in the range of 1.5 to 3.0 from the viewpoint of mechanical properties.
- the range of the degree of dispersion is more preferably 1.8 to 2.7, and 2.0 to 2.4 is particularly preferable in terms of moldability and mechanical properties.
- the weight average molecular weight and dispersity are values in terms of standard polymethyl methacrylate as measured by gel permeation chromatography (GPC) using hexafluoroisopropanol or chloroform as a solvent.
- the polylactic acid resin composition constituting the molded article containing the polylactic acid block copolymer obtained in the present invention comprises a polylactic acid block copolymer comprising a segment comprising L-lactic acid units and a segment comprising D-lactic acid units. It is preferable that it is a polylactic acid resin composition containing 60% or more. More preferably, it is 70% or more, and particularly preferably 80% or more.
- the amount of lactide and the amount of oligomer contained in the polylactic acid resin composition contained in the molded product containing the polylactic acid block copolymer obtained are each preferably 5% or less. More preferably, it is 3% or less, and particularly preferably 1% or less.
- the amount of lactic acid contained in poly-L-lactic acid or poly-D-lactic acid is preferably 2% or less. More preferably, it is 1% or less, More preferably, it is 0.5% or less, Most preferably, it is 0.1% or less.
- a method for producing a molded product containing the obtained polylactic acid block copolymer includes sheet molding, injection molding, extrusion molding, blow molding, vacuum molding, press molding, and the like.
- Known molding methods can be mentioned, and injection molding, blow molding, vacuum molding and press molding are preferred in terms of transparency and heat resistance.
- examples thereof include a method of obtaining a sheet by sandwiching a polylactic acid resin composition containing a polylactic acid block copolymer with a predetermined mold.
- the degree of crystallinity can be increased by heat-treating the obtained sheet at a predetermined temperature for a predetermined time.
- a press sheet having a thickness of 100 ⁇ m is manufactured by heating at 240 ° C.
- a method of performing heat treatment at 80 ° C. for 5 minutes and 110 ° C. for 30 minutes can be given.
- the mold temperature is preferably a temperature range from the glass transition temperature to the melting point of the polylactic acid block copolymer and from the melting point, preferably in terms of transparency and heat resistance. Is set to a temperature range of 60 ° C. or higher and 220 ° C. or lower, more preferably, a temperature range of 70 ° C. or higher and 200 ° C. or lower, more preferably a temperature range of 80 ° C. or higher and 180 ° C. or lower, and a molding cycle of 150 seconds or shorter.
- the injection molding is preferably performed for 90 seconds or less, more preferably for 60 seconds or less, and even more preferably for 50 seconds or less.
- blow molding when blow molding is performed as the method for producing the molded body, for example, a polylactic acid block copolymer having a bottomed tube-shaped molded article having a crystallinity that can be blow-molded by injection molding according to the above method ( Parison), and then the temperature range of the glass transition point of the polylactic acid block copolymer and the glass transition point + 80 ° C. or less, preferably 60 ° C. or more and 140 ° C. or less, more preferably 70 ° C. or more, 130
- a molded body is obtained by moving to a blow molding die set in a temperature range of °C or less and supplying compressed air from an air nozzle while stretching with a stretching rod.
- the sheet or film when vacuum forming is performed as a method for producing the molded body, after obtaining a sheet or film having a crystallinity that can be formed once, the sheet or film is heated to 60 to 150 ° C. with a heater such as a hot plate or hot air.
- the mold is preferably heated at 65 to 120 ° C., more preferably at 70 to 90 ° C., and the sheet is set at a mold temperature of 30 to 150 ° C., preferably 40 to 100 ° C., more preferably 50 to 90 ° C.
- There is a method of molding by making the inside of the mold depressurized at the same time as making it closely contact.
- the polylactic acid block copolymer when press molding is performed as a method for producing the molded body, after obtaining a sheet or film having a crystallinity that can be molded once, the polylactic acid block copolymer is heated with a heater such as a hot plate or hot air. Heating is performed at ⁇ 150 ° C., preferably 65-120 ° C., more preferably 70-90 ° C., and the sheet is set at a mold temperature of 30-150 ° C., preferably 40-100 ° C., more preferably 50-90 ° C. There is a method in which the mold is made of a male mold and a female mold that are in close contact with each other and pressurized and clamped.
- the stretching treatment is performed to impart transparency.
- the shape of the formed body to be stretched is preferably a film or sheet shape.
- a temperature range of the polylactic acid stereocomplex above the glass transition point and below the melting point preferably 60 ° C. or more and 170 ° C. or less, more preferably 70 ° C. or more and 150 ° C. or less. It is preferable to stretch in the temperature range.
- the polylactic acid block copolymer obtained by the method for producing a polylactic acid block copolymer of the present invention includes, for example, a film, a sheet, a fiber / cloth, a nonwoven fabric, an injection molded product, an extrusion molded product, a vacuum / pressure molded product, and a blow molding.
- Products, and composites with other materials, etc., and these molded products are agricultural materials, horticultural materials, fishery materials, civil engineering / building materials, stationery, medical supplies, automotive parts It is useful for electrical / electronic parts, optical films, and other applications.
- mobile terminals such as relay cases, coil bobbins, optical pickup chassis, motor cases, notebook computer housings or internal parts, CRT display housings or internal parts, printer housings or internal parts, mobile phones, mobile PCs, handheld mobiles, etc.
- the weight average molecular weight and degree of dispersion are values in terms of standard polymethyl methacrylate measured by gel permeation chromatography (GPC). GPC measurement was performed using a WATERS differential refractometer WATERS410 as a detector, a WATERS MODEL510 as a pump, and a column in which Shodex GPC HFIP-806M and Shodex GPC HFIP-LG were connected in series.
- Measurement conditions were such that the flow rate was 0.5 mL / min, hexafluoroisopropanol was used as the solvent, and 0.1 mL of a solution having a sample concentration of 1 mg / mL was injected.
- (2) Melting point, melting temperature and heat of fusion The melting point, melting end temperature and heat of fusion were measured with a Perkin Elmer differential scanning calorimeter (DSC). Measurement conditions are a sample of 5 mg, a nitrogen atmosphere, and a heating rate of 20 ° C./min.
- the melting point refers to the peak top temperature in the crystal melting peak
- the melting end temperature refers to the peak end temperature in the crystal melting peak.
- the melting point of the block copolymer means that the temperature is increased from 30 ° C. to 250 ° C. at a temperature increase rate of 20 ° C./min at the first temperature increase, then cooled to 30 ° C. at a temperature decrease rate of 20 ° C./min. It is the melting point measured when the temperature is raised from 30 ° C. to 250 ° C. at a temperature rising rate of 20 ° C./min during warming.
- (3) Stereo complex formation rate (Sc) The stereocomplex formation rate (Sc) of the polylactic acid block copolymer and the polylactic acid stereocomplex (mixture of poly-L-lactic acid and poly-D-lactic acid) was calculated from the following formula (12).
- ⁇ Hl indicates the amount of heat based on crystal melting of poly-L-lactic acid single crystal and poly-D-lactic acid single crystal appearing at 150 ° C. or more and less than 190 ° C.
- ⁇ Hh is a stereocomplex crystal appearing at 190 ° C. or more and less than 250 ° C. The amount of heat based on the crystal melting of is shown.
- the stereo complex formation rate in the mixture was calculated from the crystal melting peak measured at the first temperature rise of the differential scanning calorimeter (DSC), and the stereo of the polylactic acid block copolymer after solid phase polymerization was calculated.
- the complex formation rate was raised from 30 ° C. to 250 ° C. at a temperature increase rate of 20 ° C./min at the first temperature increase, then cooled to 30 ° C. at a temperature decrease rate of 20 ° C./min, and further increased at the second temperature increase. This is calculated from the crystal melting peak measured when the temperature is raised from 30 ° C. to 250 ° C. at a rate of 20 ° C./min.
- (4) Polymer Yield The yield (Y) of the polylactic acid block copolymer was calculated from the following formula (13).
- the total ⁇ Hm of the melting enthalpy and stereocomplex crystal melting enthalpy derived from the poly-L-lactic acid single crystal and the poly-D-lactic acid single crystal and the crystallization enthalpy ⁇ Hc at the time of temperature rise of the molded product were measured, respectively. ).
- Relative crystallinity [( ⁇ Hm ⁇ Hc) / ⁇ Hm] ⁇ 100 (14) (7) Haze value The haze value was measured as an index of the transparency of the molded product. Using a Nippon Denshoku haze meter NDH-300A, a haze value was measured according to JIS K 7105 for a sheet-like molded body having a thickness of 0.1 mm. (8) Storage elastic modulus The storage elastic modulus was measured as an index of the heat resistance of the molded body. A central part of a sheet-like molded body having a thickness of 0.1 mm is cut into 40 mm ⁇ 2 mm to form a strip-like sample, and the temperature rise rate is 2 ° C.
- PLA1 poly-L-lactic acid
- PLA1 had a weight average molecular weight of 18,000, a dispersity of 1.5, a melting point of 149 ° C., and a melting end temperature of 163 ° C.
- Reference Example 2 The PLA 1 obtained in Reference Example 1 was crystallized at 110 ° C. for 1 hour under a nitrogen atmosphere, and then solid-phased at a pressure of 60 Pa for 3 hours at 140 ° C., 3 hours at 150 ° C., and 5 hours at 160 ° C. Polymerization was performed to obtain poly-L-lactic acid (PLA2).
- PLA2 had a weight average molecular weight of 43,000, a dispersity of 1.8, a melting point of 159 ° C., and a melting end temperature of 176 ° C.
- Reference Example 3 The PLA 1 obtained in Reference Example 1 was crystallized at 110 ° C. for 1 hour in a nitrogen atmosphere, and then solid-phased at a pressure of 60 Pa for 3 hours at 140 ° C., 3 hours at 150 ° C., and 12 hours at 160 ° C. Polymerization was performed to obtain poly-L-lactic acid (PLA3).
- PLA3 had a weight average molecular weight of 17,000, a dispersity of 1.8, a melting point of 168 ° C., and a melting end temperature of 189 ° C.
- PLA5 poly-L-lactic acid
- PLA5 had a weight average molecular weight of 262,000, a dispersity of 2.1, a melting point of 171 ° C., and a melting end temperature of 191 ° C.
- Reference Example 6 1 kg of 90 wt% L-lactic acid aqueous solution was oligomerized by distilling water while stirring at 150 ° C. and 4,000 Pa for 6 hours.
- PLA6 had a weight average molecular weight of 154,000, a dispersity of 2.6, a melting point of 172 ° C., and a melting end temperature of 194 ° C.
- PLA7 Poly-L-lactic acid
- PLA7 was obtained by carrying out the polymerization reaction in the same manner as in Reference Example 1 except that the polymerization reaction catalyst was changed to 0.02 part of tin (II) acetate and 0.13 part of methanesulfonic acid. It was.
- PLA7 had a weight average molecular weight of 19000, a dispersity of 1.5, a melting point of 150 ° C., and a melting end temperature of 164 ° C.
- the PLA 7 obtained in Reference Example 1 was crystallized at 110 ° C.
- PLA8 had a weight average molecular weight of 14,000, a dispersity of 1.8, a melting point of 169 ° C., and a melting end temperature of 189 ° C.
- Reference Example 9 The PLA 7 obtained in Reference Example 1 was crystallized at 110 ° C. for 1 hour in a nitrogen atmosphere, and then solid-phased at a pressure of 60 Pa for 3 hours at 140 ° C., 3 hours at 150 ° C., and 12 hours at 160 ° C.
- PLA9 poly-L-lactic acid
- PLA9 had a weight average molecular weight of 221,000, a dispersity of 1.8, a melting point of 170 ° C., and a melting end temperature of 191 ° C.
- Reference Example 10 In a reaction vessel equipped with a stirrer and a reflux apparatus, 50 parts of a 90% D-lactic acid aqueous solution was placed, the temperature was raised to 150 ° C., and the mixture was reacted for 3.5 hours while gradually reducing the pressure to distill off water.
- PDA1 poly-D-lactic acid
- PDA1 had a weight average molecular weight of 15,000, a dispersity of 1.5, a melting point of 147 ° C., and a melting end temperature of 163 ° C.
- PDA2 poly-D-lactic acid
- PDA2 had a weight average molecular weight of 29,000, a dispersity of 1.6, a melting point of 150 ° C., and a melting end temperature of 168 ° C.
- Reference Example 12 The PDA 1 obtained in Reference Example 7 was crystallized at 110 ° C. for 1 hour in a nitrogen atmosphere, and then solid phase at a pressure of 60 Pa for 3 hours at 140 ° C., 3 hours at 150 ° C., and 6 hours at 160 ° C.
- PDA3 poly-D-lactic acid
- PDA3 had a weight average molecular weight of 42,000, a dispersity of 1.6, a melting point of 158 ° C., and a melting end temperature of 176 ° C.
- the PDA 1 obtained in Reference Example 7 was crystallized at 110 ° C. for 1 hour in a nitrogen atmosphere, and then solid-phased at a pressure of 60 Pa for 3 hours at 140 ° C., 3 hours at 150 ° C., and 18 hours at 160 ° C.
- Polymerization was performed to obtain poly-D-lactic acid (PDA4).
- PDA4 had a weight average molecular weight of 1,98,000, a dispersity of 2.0, a melting point of 170 ° C., and a melting end temperature of 191 ° C.
- 1 kg of 90 wt% D-lactic acid aqueous solution was oligomerized by distilling water while stirring at 150 ° C. and 4,000 Pa for 6 hours.
- 0.2 g of stannous chloride and 0.2 g of p-toluenesulfonic acid were added, and poly-L-lactic acid (PDA5) was obtained by performing melt polymerization at 180 ° C. and 1,300 Pa for 3 hours. .
- PDA5 had a weight average molecular weight of 16,000, a dispersity of 1.5, a melting point of 144 ° C., and a melting end temperature of 160 ° C.
- a polymerization reaction was carried out in the same manner as in Reference Example 10 except that the polymerization reaction catalyst was changed to 0.02 part of tin (II) acetate and 0.13 part of methanesulfonic acid to obtain poly-D-lactic acid (PDA6). It was. PDA6 had a weight average molecular weight of 16,000, a dispersity of 1.5, a melting point of 149 ° C., and a melting end temperature of 162 ° C.
- PDA8 had a weight average molecular weight of 50,000, a dispersity of 1.6, a melting point of 160 ° C., and a melting end temperature of 177 ° C.
- Reference Example 7 The PDA 6 obtained in Reference Example 7 was subjected to crystallization treatment at 110 ° C.
- PDA9 poly-D-lactic acid
- the twin-screw extruder is provided with a plasticizing part set at a temperature of 180 ° C.
- the structure can be mixed under application of shear.
- Poly-L-lactic acid and poly-D-lactic acid were mixed at a mixing temperature of 200 ° C. under application of shear.
- the combinations of poly-L-lactic acid and poly-D-lactic acid are as shown in Table 1.
- the polymer after mixing was subjected to crystallization treatment at a pressure of 13.3 Pa and 110 ° C. for 2 hours, and then measured for physical properties.
- Examples 1 to 12 and Comparative Example 5 had a high molecular weight of 100,000 or more in weight average molecular weight at the time of mixing, whereas Comparative Examples 1 to 4 had a weight average molecular weight in the case of mixing. Was less than 100,000.
- the thermal characteristics during mixing the mixture was observed to have a high melting point at all levels of Examples 1 to 7 and Comparative Examples 1 to 5.
- the stereocomplex formation rate was as high as 60% or more in Examples 1 to 12 and Comparative Examples 1 to 4, but the molecular weights of both poly-L-lactic acid and poly-D-lactic acid to be mixed were 100,000 or more. In Comparative Example 5, which was a combination, the stereo complex formation rate was low.
- Step of solid-phase polymerization of a mixture of poly-L-lactic acid and poly-D-lactic acid The mixture obtained in (1) is solid-phased in a vacuum dryer at 140 ° C. and a pressure of 13.3 Pa for 4 hours. Polymerization was carried out, and then the temperature was raised to 150 ° C. for 4 hours, and further to 160 ° C. for 10 hours to carry out solid phase polymerization.
- Examples 1 to 12 (SB1 to SB12), Comparative Examples 1 to 3 (SB13 to SB15) and 5 (SB17) using high molecular weight segments as polylactic acid to be mixed are all used.
- Comparative Example 4 which is a combination of low molecular weights of poly-L-lactic acid and poly-D-lactic acid mixed with a low molecular weight of 100,000 or less, the yield after solid-phase polymerization was high. Was 90% or more and was a low value.
- the thermal characteristics after solid-phase polymerization high melting point of the mixture was observed at all levels of Examples 1 to 12 (SB1 to 12) and Comparative Examples 1 to 5 (SB13 to SB17).
- the stereo complex formation rate was high at 80% or more in Examples 1 to 12 (SB1 to SB12) and Comparative Examples 1 to 4 (SB13 to SB16), but Stereo Complex formation was performed for Comparative Example 5 (SB17). The rate was low.
- the temperature-falling crystallization temperature is 130 ° C. or higher in Examples 1 to 12 (SB1 to SB12) and Comparative Example 4 (SB16), while Comparative Examples 1 to 3 (SB13 to SB15) and 5 (SB17) are used.
- the weight average molecular weight at the time of mixing was 84,000.
- a part of the melting point was increased due to the formation of a stereo complex.
- the polymer was only partially melted and polylactic acid single crystals remained, and as a result, the stereocomplex formation rate was as low as 26%.
- Step of solid-phase polymerization of a mixture of poly-L-lactic acid and poly-D-lactic acid The mixture obtained in (1) was heat-treated at 110 ° C. for 2 hours at a pressure of 66.6 Pa, and then at 130 ° C. Solid state polymerization was performed by heating for 5 hours at 140 ° C. for 25 hours (30 hours in total).
- the molecular weight after solid phase polymerization was 151,000, but the yield after solid phase polymerization was as low as 90% or less.
- the thermal characteristics after solid-phase polymerization a high melting point was observed due to the formation of stereocomplexes, and the stereocomplex formation rate was also high.
- the temperature-falling crystallization temperature after solid-phase polymerization was 124 ° C., which was lower than 130 ° C. or higher shown in the examples.
- Example 1 the mixture of poly-L-lactic acid and poly-D-lactic acid was filled in a glass container without gaps, sealed and heated.
- the heating temperature and time are the same as in Example 1.
- the solid phase polymerization did not proceed only by heating the mixture, and the weight average molecular weight of the sample SB19 after heating was 81,000, which was lower than that of Example 1.
- the yield of this sample SB19 was 98%, the dispersity was 2.7, and the melting point was 162 ° C / 215 ° C.
- the cooling crystallization temperature was 112 ° C under reduced pressure. It was low compared with Example 1 which performed solid-state polymerization by this.
- PLA11 had a weight average molecular weight of 122,000, a dispersity of 1.7, a melting point of 170 ° C., and a melting end temperature of 188 ° C.
- Reference Example 21 In a reaction vessel equipped with a stirrer, 100 parts of D-lactide was uniformly dissolved at 160 ° C. in a nitrogen atmosphere, 0.003 part of tin octylate was added, and a polymerization reaction was carried out for 6 hours. After completion of the polymerization reaction, the reaction product was dissolved in chloroform, precipitated in methanol (5 times the amount of chloroform) with stirring, and the monomer was completely removed to obtain poly-D-lactic acid (PDA10).
- PDA10 poly-D-lactic acid
- PDA10 had a weight average molecular weight of 1.3 million, a dispersity of 1.6, a melting point of 180 ° C., and a melting end temperature of 194 ° C.
- PDA10 had a weight average molecular weight of 1.3 million, a dispersity of 1.6, a melting point of 180 ° C., and a melting end temperature of 194 ° C.
- 100 parts of D-lactide and 0.05 part of ethylene glycol were uniformly dissolved at 150 ° C. in a nitrogen atmosphere, and then 0.003 part of tin octylate was added and polymerized for 3 hours. Reaction was performed. After completion of the polymerization, the reaction product was dissolved in chloroform, precipitated in methanol (5 times the amount of chloroform) with stirring, and the monomer was completely removed to obtain poly-D-lactic acid (PDA11).
- PDA11 had a weight average molecular weight of 1,98,000, a dispersity of 1.7, a melting point of 172 ° C., and a melting end temperature of 190 ° C.
- Reference Example 23 In a reaction vessel equipped with a stirrer, 100 parts of D-lactide and 0.1 part of ethylene glycol are uniformly dissolved in a nitrogen atmosphere at 150 ° C., and then 0.003 part of tin octylate is added and polymerized for 3 hours. Reaction was performed. Thereafter, 0.01 part of a phosphorus-based catalyst deactivator was added to the reaction system and stirred for 10 minutes to deactivate the catalyst.
- poly-D-lactic acid had a weight average molecular weight of 122,000, a dispersity of 1.7, a melting point of 169 ° C., and a melting end temperature of 188 ° C.
- Process of mixing poly-L-lactic acid and poly-D-lactic acid Mixing of poly-L-lactic acid and poly-D-lactic acid is performed using a batch type twin-screw kneader (labor plast mill) manufactured by Toyo Seiki. A polylactic acid mixture was obtained.
- test conditions are kneading temperature 245 ° C., kneading rotation speed 120 rpm, kneading time is 10 minutes for comparative examples 8 and 11, and 60 minutes for comparative examples 9 and 12.
- the combinations of poly-L-lactic acid and poly-D-lactic acid are as shown in Table 2.
- the weight average molecular weight of the polylactic acid mixture was as high as 100,000 or more in Comparative Example 8 (SC14) and Comparative Example 11 (SC17), while Comparative Example 9 (SC15) and Comparative Example 12 having a long kneading time of 60 minutes. In (SC18), there was a downward trend of 100,000 or less.
- the melting point of the polylactic acid mixture was observed to be 200 ° C. or more due to stereocomplex formation, but the stereocomplex formation rate was 60% or less in both Comparative Examples 8 and 11 and was lower than that in Examples 1-8. .
- Regarding the cooling crystallization temperature of the polylactic acid mixture it was observed at 105 ° C. and 125 ° C.
- the weight average molecular weight of the polylactic acid mixture was 84,000 and 510,000 for Comparative Example 10 (SC16) and Comparative Example 13 (SC19), respectively, and was as long as Comparative Examples 9 and 12 The molecular weight tended to decrease with time kneading.
- the temperature drop crystallization temperature of the polylactic acid mixture was 103 ° C. and 120 ° C. for Comparative Example 10 (SC16) and Comparative Example 13 (SC19), respectively, and Comparative Example 9 (SC15) Almost identical to Example 12 (SC18).
- the weight average molecular weight of the polylactic acid mixture obtained by kneading is 110,000 to 120,000 in Comparative Examples 14 to 16 (SC20 to SC22), whereas the molecular weight is as low as 65,000 in Comparative Example 17 (SC23). It was a tendency to become.
- the melting point of the polylactic acid mixture was observed to be 200 ° C. or higher due to the formation of a stereocomplex, but the temperature-falling crystallization temperature of the polylactic acid mixture was observed only in Comparative Examples 14 to 16 (SC20 to SC22) combined with a crystal nucleating agent. It was.
- Example 13 to 24, Comparative Examples 18 to 24 As shown in Table 3, the polylactic acid block copolymers (SB1 to SB12, SB13 to SB18) obtained in Examples 1 to 12 and Comparative Examples 1 to 6 and the polylactic acid mixture (SB19) obtained in Comparative Example 7
- the mixture was melt-kneaded at 240 ° C. together with 0.05 part of a phosphorus-based catalyst deactivator using a twin-screw extruder to deactivate the catalyst. Subsequently, the sheet was melted by heating at 240 ° C. for 2 minutes, and then pressed at a press temperature of 80 ° C. to produce a press sheet having a thickness of 0.1 mm. Next, the press sheet was heat-treated at 110 ° C. for 30 minutes under a nitrogen atmosphere to obtain sheet-like molded bodies for various measurements.
- Table 3 shows various physical property values measured by sampling the central part of the sheet-like molded body.
- the relative crystallinity of the sheet-like molded bodies of Examples 13 to 24 and Comparative Examples 18 to 24 was 100%. Further, when the haze value was measured for a sample cut out to a size of 5 cm ⁇ 5 cm from the center of the sheet-like molded body, all of the sheet molded bodies of Examples 13 to 24 were less than 10% and excellent in transparency. It was. On the other hand, the haze values of the sheet molded articles of Comparative Examples 18 to 24 were 10% or more except that the sheet molded article of Comparative Example 21 was less than 10%.
- the sheet-like molded body was cut into 40 mm ⁇ 2 mm from the central portion to form a strip-like sample, and the storage elastic modulus at 130 ° C. by dynamic viscoelasticity was measured. All were 2 GPa or more and were excellent in heat resistance. When the tensile strength was measured about the said strip-shaped sample, all were 60 Mpa or more.
- the sheet molded bodies of Comparative Examples 18 to 24 had a storage elastic modulus at 130 ° C. of 2 GPa or more in Comparative Examples 21, 23 and 24, but the other was less than 2 GPa. Moreover, about the tensile strength of the strip-shaped sample, all the sheet compacts were less than 60 MPa, and the physical property was low compared with the Example.
- the sheet-like molded body is heated using a vacuum molding machine under the conditions of a heating temperature of 100 ° C. and a heating time of 60 seconds, and is brought into close contact with the mold at a mold temperature of 40 ° C., and at the same time, the inside of the mold is decompressed.
- a cylindrical container having an inner diameter of 6 cm and a depth of 10 cm was obtained.
- This cylindrical container was heat-treated at 110 ° C. for 30 minutes under a nitrogen atmosphere, then dropped onto the concrete from the bottom of the container at a height of 2 m, filled with water and covered with a lid, and dropped impact The number of times until the container was damaged and water leaked was measured.
- Example 25 About the polylactic acid block copolymer SB1 obtained by solid phase polymerization in Example 1, the catalyst was deactivated before producing a sheet compact. The method for deactivating the catalyst is the same as in Examples 13-24. Subsequently, the polylactic acid block copolymer subjected to catalyst deactivation was heated and melted at 240 ° C. for 2 minutes, and then pressed at a press temperature of 80 ° C. to prepare a 0.1 mm thick press sheet, It was set as the sheet-like molded object for various measurements by cooling in ice water. The method for measuring various physical properties of the sheet-like molded body is the same as in Examples 13-24.
- Example 25 the relative crystallinity of the sheet-like molded body of Example 25 was as low as 10% because the molded body was not heat-treated. Further, the haze value of the sheet-like molded body was 2% because the molded body was not heat-treated, and the transparency was high. However, the tensile strength and impact resistance of the sheet-like molded product are lower than those of Examples 13 to 24, and the storage elastic modulus at 130 ° C. is not measured because the molded product was broken during the temperature rising process. It was possible. (Comparative Example 25) About the polylactic acid mixture SC1 obtained in Example 1, the catalyst was deactivated before producing the sheet compact. The method for deactivating the catalyst is the same as in Examples 13-24. Subsequently, molded bodies for measuring various physical properties were produced using SC1 in which the catalyst was deactivated. The method for producing a molded body and the method for measuring physical properties are the same as in Examples 13-24.
- the relative crystallinity of the sheet-like molded body of Comparative Example 25 was 100%. Moreover, the haze value of the sheet-like molded body was 14% for the molded body, and the transparency was high. Although the sheet-like molded product had a high storage elastic modulus at 130 ° C. of 2.4 GPa, the tensile strength and impact resistance were inferior to those of Examples 13-24. (Comparative Examples 26, 27, 29, 30) About the polylactic acid mixture (SC19, SC20, SC22, SC23) obtained in Comparative Examples 8, 9, 11, and 12, the catalyst was deactivated before producing a sheet molded body. The method for deactivating the catalyst is the same as in Examples 13-24.
- molded articles for measuring various physical properties were prepared using the polylactic acid mixture in which the catalyst was deactivated.
- a method for preparing a molded body for measuring various physical properties and a method for measuring physical properties are the same as in Examples 13 to 24.
- the relative crystallinity of the sheet-like molded bodies of each comparative example was 100% in Comparative Examples 27, 29, and 30, respectively, but 78% in Comparative Example 26 was low. Further, the haze value of the sheet-like molded body was 22% in Comparative Example 31, but was 40% or more in Comparative Examples 26, 27, and 29, and the transparency was lower than that in Examples 13 to 24. . Furthermore, the storage elastic modulus at 130 ° C. of the sheet molded body was 2 GPa or less, which was a result of inferior high-temperature rigidity.
- Comparative Example 26 having a high molecular weight of the molded article, but Comparative Examples 28, 30, and 31 were lower than those in Examples 13-24.
- Comparative Examples 28 and 31 About the polylactic acid mixture (SC21, SC24) obtained in Comparative Examples 10 and 13, the catalyst was deactivated before producing the sheet compact. The method for deactivating the catalyst is the same as in Examples 13-24. Subsequently, molded articles for measuring various physical properties were prepared using the polylactic acid mixture in which the catalyst was deactivated. The method for producing a molded article for measuring various physical properties and the method for measuring physical properties are the same as in Examples 13-24.
- the relative crystallinity of the sheet-like molded bodies of the respective comparative examples was 100%.
- the haze values of the molded products were as low as 50% or more in Comparative Examples 32 and 33, and the transparency was low in Comparative Examples 34 to 36 due to the combined use of the crystal nucleating agent.
- the mechanical properties of the molded articles were all lower than those of Examples 13 to 24.
- Comparative Example 36 having a low molecular weight tended to have lower physical properties in both tensile strength and impact resistance.
- the polylactic acid block copolymer obtained by the production method of the present invention was excellent in heat resistance, crystallinity and transparency even in a molded body.
- the production method of the present invention provides a polylactic acid block copolymer having a high molecular weight and a high melting point, it can be suitably used in fields requiring heat resistance, which was difficult to use with polylactic acid homopolymers.
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Abstract
Description
Sc=ΔHh/(ΔHl+ΔHh)×100>60 (1)
ここで、ΔHh:ステレオコンプレックス結晶に基づく熱量(J/g)、ΔHl:ポリ-L-乳酸単独結晶およびポリ-D-乳酸単独結晶の結晶融解に基づく熱量(J/g)、
または、[2]ポリ-L-乳酸とポリ-D-乳酸のうち、重量平均分子量の高い方と重量平均分子量の低い方の比が2以上30未満であるポリ-L-乳酸とポリ-D-乳酸を混合し、重量平均分子量が9万以上、かつステレオコンプレックス形成率(Sc)が下記式(1)を満たす混合物を得る工程、次いで、混合物を混合物の融点より低い温度で固相重合する工程からなるポリ乳酸ブロック共重合体の製造方法、である。
ここで、ΔHh:ステレオコンプレックス結晶に基づく熱量(J/g)、ΔHl:ポリ-L-乳酸単独結晶およびポリ-D-乳酸単独結晶の結晶融解に基づく熱量(J/g)
本発明のポリ乳酸ブロック共重合体の製造方法は、原料となるポリ-L-乳酸とポリ-D-乳酸のいずれか一方の重量平均分子量が17万以上であり、かつもう一方の重量平均分子量が2万以上であることが好ましい。
本発明のポリ乳酸ブロック共重合体の製造方法は、得られるポリ乳酸ブロック共重合体が下記式(3)を満たすことが好ましい。
本発明のポリ乳酸ブロック共重合体の製造方法は、得られるポリ乳酸ブロック共重合体のDSC測定において、ポリ乳酸ブロック共重合体を250度まで昇温して3分間恒温状態にした後、冷却速度20℃/minで降温した際の降温結晶化温度が130℃以上であることが好ましい。
ここで、ΔHm:成形体の結晶融解エンタルピー(J/g)、ΔHc:成形体の昇温時結晶化エンタルピー(J/g)
本発明のポリ乳酸ブロック共重合体の製造方法は、混合物に含まれる触媒が、混合物100重量部に対して0.001~0.5重量部であることが好ましい。
本発明においては、ポリ乳酸ブロック共重合体一分子あたりに含まれるL-乳酸単位からなるセグメントおよびD-乳酸単位からなるセグメントの合計数が3以上であることが、高融点のポリ乳酸ステレオコンプレックスを形成しやすいポリ乳酸ブロック共重合体が得られる点で好ましい。さらに好ましくは5以上であり、7以上であることが特に好ましい。
(原料として用いるポリ乳酸の製造方法)
本発明において、原料として用いるL―乳酸単位からなるポリ-L-乳酸およびD-乳酸単位からなるポリ-D-乳酸の製造方法については、特に限定されるものではなく、一般のポリ乳酸の製造方法を利用することができる。具体的には、L-乳酸またはD-乳酸を原料として、一旦、環状2量体であるL-ラクチドまたはD-ラクチドを生成せしめ、その後、開環重合を行う2段階のラクチド法と、当該原料を溶媒中または非溶媒中で直接脱水縮合を行う1段階の直接重合法などが知られており、いずれの製法を利用してもよい。
(ポリ乳酸の混合方法)
次にポリ-L-乳酸とポリ-D-乳酸を混合する工程について説明する。
また、混合に用いるポリ-L-乳酸とポリ-D-乳酸の結晶化の有無については特に限定されず、結晶化したポリ-L-乳酸とポリ-D-乳酸を混合してもよいし、溶融状態のポリ-L-乳酸とポリ-D-乳酸を混合することもできる。混合に用いるポリ-L-乳酸とポリ-D-乳酸の結晶化を行う場合、具体的な方法として気相中または液相中において結晶化処理温度で保持する方法およびポリ-L-乳酸とポリ-D-乳酸の溶融混合物を延伸または剪断の操作を行いながら冷却固化させる方法などが挙げられ、操作が簡便であるという観点においては、気相中または液相中において結晶化処理温度で保持する方法が好ましい。
また、混合後におけるポリ-L-乳酸とポリ-D-乳酸の混合物の分散度は1.5~4.0の範囲が好ましい。さらに好ましくは2.0~3.7の範囲であり、特に好ましくは2.5~3.5の範囲である。ここで、分散度とは、混合物の数平均分子量に対する重量平均分子量の割合のことをいい、具体的には溶媒としてヘキサフルオロイソプロパノールまたはクロロホルムを用いたゲルパーミエーションクロマトグラフィー(GPC)測定による標準ポリメチルメタクリレート換算の値である。
(固相重合)
次に、ポリ-L-乳酸とポリ-D-乳酸の混合物を固相重合する工程について説明する。この固相重合工程では、ポリ-L-乳酸とポリ-D-乳酸が、主に直接重合することによりポリ乳酸ブロック共重合体が得られる。
固相重合工程においては、混合物の分散度が小さくなることが好ましい。具体的には固相重合前の混合物の分散度が1.5~4.0の範囲から固相重合後にはポリ乳酸ブロック共重合体の分散度が1.5~2.7の範囲になることが好ましい。さらに好ましくは固相重合前の混合物の分散度が2.0~3.7の範囲が固相重合後にはポリ乳酸ブロック共重合体の分散度が1.8~2.6の範囲に小さくなることであり、特に好ましくは、固相重合前の混合物の分散度が2.5~3.5の範囲から固相重合後にはポリ乳酸ブロック共重合体の分散度が2.0~2.5の範囲になることである。
(ポリ乳酸ブロック共重合体)
本発明の製造方法により得られるポリ乳酸ブロック共重合体の重量平均分子量は、特に限定されるものではないが、10万以上30万未満の範囲であることが成形性および機械物性の点で好ましい。さらに好ましくは12万以上28万未満の範囲であり、14万以上26万未満の範囲であることが特に好ましい。また、ポリ乳酸ブロック共重合体の分散度は、1.5~3.0の範囲が機械物性の点で好ましい。分散度の範囲は1.8~2.7であることがさらに好ましく、2.0~2.4であることが成形性および機械物性の点で特に好ましい。なお、重量平均分子量および分散度は、溶媒としてヘキサフルオロイソプロパノールまたはクロロホルムを用いたゲルパーミエーションクロマトグラフィー(GPC)測定による標準ポリメチルメタクリレート換算の値である。
本発明の製造方法により得られるポリ乳酸ブロック共重合体は、150℃~190℃の範囲でポリ-L-乳酸単独結晶およびポリ-D-乳酸単独結晶に基づく融点を有し、また、ステレオコンプレックス形成によりステレオコンプレックス結晶に基づく融点を200~230℃の範囲で有する。ステレオコンプレックス結晶由来の融点の好ましい範囲は205℃~230℃であり、210℃~230℃の温度範囲がさらに好ましく、215℃~230℃の温度範囲が特に好ましい。原料として用いるポリ-L-乳酸(もしくはポリ-D-乳酸)に含まれる主成分のL-乳酸(もしくはD-乳酸)単位の量により結晶性を制御することが可能で、結晶性が高いほどステレオコンプレックス結晶由来の融点は上昇し、好ましい。例えば、ポリ-L-乳酸中に含まれる主成分のL-乳酸の好ましい範囲は前記のとおり、好ましくは80mol%であり、90mol%以上含有していることがより好ましく、95mol%以上含有していることがさらに好ましく、98mol%以上含有していることが特に好ましい。
本発明の製造方法により得られるポリ乳酸ブロック共重合体は、成形性および耐熱性に優れるという点で降温結晶化温度(Tc)が130℃以上であることが好ましい。ここで、成型体の降温結晶化温度(Tc)とは、示差走査熱量計(DSC)により昇温速度20℃/minで30℃から250℃まで昇温した後、250℃で3分間恒温状態に維持を行い、冷却速度20℃/minで降温した際に測定したポリ乳酸結晶由来の結晶化温度である。結晶化温度(Tc)は、特に限定されるものではないが、耐熱性および透明性の観点から、130℃以上が好ましく、132℃以上がより好ましく、135℃以上が特に好ましい。
ここで、ΔHm:成形体の結晶融解エンタルピー(J/g)、ΔHc:成形体の昇温時結晶化エンタルピー(J/g)である。
本発明において得られるポリ乳酸ブロック共重合体を含む成形体に含まれるポリ乳酸ブロック共重合体は、ポリ乳酸ブロック共重合体一分子あたりに含まれるL-乳酸単位からなるセグメントおよびD-乳酸単位からなるセグメントの合計数が3以上であることが、高融点のポリ乳酸ステレオコンプレックスを形成しやすいポリ乳酸ブロック共重合体が得られる点で好ましい。また、1セグメントあたりの分子量は2千~5万であることが好ましい。さらに好ましくは、4千~4.5万であり、5千~4万であることが機械物性の点で特に好ましい。
本発明のポリ乳酸ブロック共重合体の製造方法において、得られるポリ乳酸ブロック共重合体を含む成形体に含まれるポリ乳酸ブロック共重合体の重量平均分子量は、特に限定されるものではないが、機械物性の点で10万以上30万未満であることが好ましい。12万以上28万未満であることがさらに好ましく、14万以上26万未満であることが成形性および機械物性の点で特に好ましい。また、本発明において得られるポリ乳酸ブロック共重合体を含む成形体に含まれるポリ乳酸ブロック共重合体の分散度は、1.5~3.0の範囲が機械物性の点で好ましい。分散度の範囲が1.8~2.7であることがさらに好ましく、2.0~2.4であることが成形性および機械物性の点で特に好ましい。なお、重量平均分子量および分散度とは、溶媒としてヘキサフルオロイソプロパノールまたはクロロホルムを用いたゲルパーミエーションクロマトグラフィー(GPC)測定による標準ポリメチルメタクリレート換算の値である。
(1)分子量および分散度
重量平均分子量および分散度は、ゲルパーミエーションクロマトグラフィー(GPC)により測定した標準ポリメチルメタクリレート換算の値である。GPCの測定は、検出器にWATERS社示差屈折計WATERS410を用い、ポンプにWATERS社MODEL510を用い、カラムにShodex GPC HFIP-806MとShodex GPC HFIP-LGを直列に接続したものを用いて行った。測定条件は、流速0.5mL/minとし、溶媒にヘキサフルオロイソプロパノールを用い、試料濃度1mg/mLの溶液を0.1mL注入した。
(2)融点、融解温度および融解熱量
融点、融解終了温度および融解熱量は、パーキンエルマー社示差走査型熱量計(DSC)により測定した。測定条件は、試料5mg、窒素雰囲気下、昇温速度が20℃/minである。
(3)ステレオコンプレックス形成率(Sc)
ポリ乳酸ブロック共重合体およびポリ乳酸ステレオコンプレックス(ポリ-L-乳酸とポリ-D-乳酸の混合物)のステレオコンプレックス形成率(Sc)は、下記式(12)から算出した。
ここで、ΔHlは150℃以上190℃未満に現れるポリ-L-乳酸単独結晶およびポリ-D-乳酸単独結晶の結晶融解に基づく熱量を示し、ΔHhは190℃以上250℃未満に現れるステレオコンプレックス結晶の結晶融解に基づく熱量を示す。
(4)ポリマーの収率
ポリ乳酸ブロック共重合体の収率(Y)は、下記式(13)から算出した。
但し、固相重合前の混合物重量をWp、固相重合後のポリ乳酸ブロック共重合体の重量をWsとする。
(5)ポリマーの降温結晶化温度
ポリ乳酸ブロック共重合体およびポリ-L-乳酸とポリ-D-乳酸の混合物の降温結晶化温度は、パーキンエルマー社示差走査型熱量計(DSC)により測定した。具体的には、試料5mgを示差走査熱量計(DSC)により窒素雰囲気下で昇温速度20℃/minで30℃から250℃まで昇温した後、250℃で3分間恒温状態に維持を行い、冷却速度20℃/minで降温した際に測定される結晶化ピークトップの温度を降温結晶化温度とした。
(6)相対結晶化度
ポリ乳酸ブロック共重合体およびポリ-L-乳酸とポリ-D-乳酸の混合物の相対結晶化度は、パーキンエルマー社示差走査型熱量計(DSC)により成形体中のポリ-L-乳酸単独結晶およびポリ-D-乳酸単独結晶由来の融解エンタルピーとステレオコンプレックス結晶融解エンタルピーの合計ΔHmと、成形体の昇温時の結晶化エンタルピーΔHcをそれぞれ測定し、下記式(14)から算出した。
(7)ヘイズ値
成形体の透明性の指標としてヘイズ値の測定を行った。厚さ0.1mmのシート状成形体につき日本電色工業製ヘイズメーターNDH-300Aを用いて、JIS K 7105に従ってヘイズ値測定を行った。
(8)貯蔵弾性率
成形体の耐熱性の指標として貯蔵弾性率を測定した。厚さ0.1mmのシート状成形体の中心部を40mm×2mmに切り出して短冊状のサンプルとし、動的粘弾性測定装置(セイコーインストルメンツ製DMS6100)にて窒素雰囲気下で昇温速度2℃/min、周波数3.5Hzにて動的粘弾性測定を行い、130℃における貯蔵弾性率を測定した。弾性率が高いほど耐熱性が高いといえる。
(9)引張強度
厚さ0.1mmのシート状成形体の中心部を40mm×2mmに切り出して短冊状のサンプルとし、ASTM D882に従い、引張強度を測定した。
(10)耐衝撃性
厚さ0.1mmのシート状成形体を真空成形して得られた容器に水を入れ、フタをした状態で2mの高さより容器底部からコンクリート上に落下させ、落下衝撃により容器が破損して水が漏れるまでの回数を測定し、下記の方法で評価を行った。
B:容器が破損して水が漏れるまでの落下回数が2~4回
F:容器が破損して水が漏れるまでの落下回数が1回。
[参考例1]
撹拌装置と還流装置を備えた反応容器中に、90%L-乳酸水溶液を50部入れ、温度を150℃にした後、徐々に減圧して水を留去しながら3.5時間反応した。その後、窒素雰囲気下で常圧にし、酢酸錫(II)0.02部を添加した後、170℃にて13Paになるまで徐々に減圧しながら7時間重合反応を行い、ポリ-L-乳酸(PLA1)を得た。PLA1の重量平均分子量は1.8万、分散度は1.5、融点は149℃、融解終了温度は163℃であった。
[参考例2]
参考例1で得られたPLA1を、窒素雰囲気下110℃で1時間結晶化処理を行った後、60Paの圧力下、140℃で3時間、150℃で3時間、160℃で5時間固相重合を行い、ポリ-L-乳酸(PLA2)を得た。PLA2の重量平均分子量は4.3万、分散度は1.8、融点は159℃、融解終了温度は176℃であった。
[参考例3]
参考例1で得られたPLA1を、窒素雰囲気下110℃で1時間結晶化処理を行った後、60Paの圧力下、140℃で3時間、150℃で3時間、160℃で12時間固相重合を行い、ポリ-L-乳酸(PLA3)を得た。PLA3の重量平均分子量は13.7万、分散度は1.8、融点は168℃、融解終了温度は189℃であった。
[参考例4]
参考例1で得られたPLA1を、窒素雰囲気下110℃で1時間結晶化処理を行った後、60Paの圧力下、140℃で3時間、150℃で3時間、160℃で18時間固相重合を行い、ポリ-L-乳酸(PLA4)を得た。PLA4の重量平均分子量は20.3万、分散度は1.9、融点は170℃、融解終了温度は189℃であった。
[参考例5]
撹拌装置を備えた反応容器中に、L-ラクチドを50部入れ、窒素雰囲気下、120℃で均一に溶解させた後、温度を150℃にし、オクチル酸錫(II)0.003部を添加して2時間反応させることにより、ポリ-L-乳酸(PLA5)を得た。PLA5の重量平均分子量は26.2万、分散度は2.1、融点は171℃、融解終了温度は191℃であった。
[参考例6]
90wt%のL-乳酸水溶液1kgを150℃、4,000Paで6時間撹拌しながら水を留出させてオリゴマー化した。このオリゴマーに塩化第一錫0.2gとp-トルエンスルホン酸0.2gとを添加し、180℃、1,300Paで6時間溶融重合を行うことによりポリ-L-乳酸プレポリマーを得た。このプレポリマーの固体を粉砕し、140℃で30時間固相重合することによりポリ-L-乳酸(PLA6)を得た。PLA6の重量平均分子量は15.4万、分散度は2.6、融点は172℃、融解終了温度は194℃であった。
[参考例7]
重合反応触媒を酢酸錫(II)0.02部およびメタンスルホン酸0.13部に変更する以外は参考例1と同様の方法にて重合反応を行い、ポリ-L-乳酸(PLA7)を得た。PLA7の重量平均分子量は1.9万、分散度は1.5、融点は150℃、融解終了温度は164℃であった。
[参考例8]
参考例1で得られたPLA7を、窒素雰囲気下110℃で1時間結晶化処理を行った後、60Paの圧力下、140℃で3時間、150℃で3時間、160℃で12時間固相重合を行い、ポリ-L-乳酸(PLA8)を得た。PLA8の重量平均分子量は14.0万、分散度は1.8、融点は169℃、融解終了温度は189℃であった。
[参考例9]
参考例1で得られたPLA7を、窒素雰囲気下110℃で1時間結晶化処理を行った後、60Paの圧力下、140℃で3時間、150℃で3時間、160℃で12時間固相重合を行い、ポリ-L-乳酸(PLA9)を得た。PLA9の重量平均分子量は22.1万、分散度は1.8、融点は170℃、融解終了温度は191℃であった。
[参考例10]
撹拌装置と還流装置を備えた反応容器中に、90%D-乳酸水溶液を50部入れ、温度を150℃にした後、徐々に減圧して水を留去しながら3.5時間反応した。その後、窒素雰囲気下で常圧にし、酢酸錫(II)0.02部を添加した後、170℃にて13Paになるまで徐々に減圧しながら7時間重合反応を行い、ポリ-D-乳酸(PDA1)を得た。PDA1の重量平均分子量は1.5万、分散度は1.5、融点は147℃、融解終了温度は163℃であった。
[参考例11]
参考例7で得られたPDA1を、窒素雰囲気下110℃で1時間結晶化処理を行った後、60Paの圧力下、140℃で3時間、150℃で3時間、160℃で3時間固相重合を行い、ポリ-D-乳酸(PDA2)を得た。PDA2の重量平均分子量は2.9万、分散度は1.6、融点は150℃、融解終了温度は168℃であった。
[参考例12]
参考例7で得られたPDA1を、窒素雰囲気下110℃で1時間結晶化処理を行った後、60Paの圧力下、140℃で3時間、150℃で3時間、160℃で6時間固相重合を行い、ポリ-D-乳酸(PDA3)を得た。PDA3の重量平均分子量は4.2万、分散度は1.6、融点は158℃、融解終了温度は176℃であった。
[参考例13]
参考例7で得られたPDA1を、窒素雰囲気下110℃で1時間結晶化処理を行った後、60Paの圧力下、140℃で3時間、150℃で3時間、160℃で18時間固相重合を行い、ポリ-D-乳酸(PDA4)を得た。PDA4の重量平均分子量は19.8万、分散度は2.0、融点は170℃、融解終了温度は191℃であった。
[参考例14]
90wt%のD-乳酸水溶液1kgを150℃、4,000Paで6時間撹拌しながら水を留出させてオリゴマー化した。このオリゴマーに塩化第一錫0.2gとp-トルエンスルホン酸0.2gとを添加し、180℃、1,300Paで3時間溶融重合を行うことによりポリ-L-乳酸(PDA5)を得た。PDA5の重量平均分子量は1.6万、分散度は1.5、融点は144℃、融解終了温度は160℃であった。
[参考例15]
重合反応触媒を酢酸錫(II)0.02部およびメタンスルホン酸0.13部に変更する以外は参考例10と同様の方法にて重合反応を行い、ポリ-D-乳酸(PDA6)を得た。PDA6の重量平均分子量は1.6万、分散度は1.5、融点は149℃、融解終了温度は162℃であった。
[参考例16]
参考例15で得られたPDA6を、窒素雰囲気下110℃で1時間結晶化処理を行った後、60Paの圧力下、140℃で3時間、150℃で3時間、160℃で3時間固相重合を行い、ポリ-D-乳酸(PDA7)を得た。PDA7の重量平均分子量は3.1万、分散度は1.6、融点は152℃、融解終了温度は170℃であった。
[参考例17]
参考例15で得られたPDA6を、窒素雰囲気下110℃で1時間結晶化処理を行った後、60Paの圧力下、140℃で3時間、150℃で3時間、160℃で6時間固相重合を行い、ポリ-D-乳酸(PDA8)を得た。PDA8の重量平均分子量は5.0万、分散度は1.6、融点は160℃、融解終了温度は177℃であった。
[参考例18]
参考例7で得られたPDA6を、窒素雰囲気下110℃で1時間結晶化処理を行った後、60Paの圧力下、140℃で3時間、150℃で3時間、160℃で18時間固相重合を行い、ポリ-D-乳酸(PDA9)を得た。PDA9の重量平均分子量は20.4万、分散度は2.0、融点は172℃、融解終了温度は193℃であった。
(実施例1~12、比較例1~5)
(1)ポリ-L-乳酸とポリ-D-乳酸を混合する工程
ポリ-L-乳酸とポリ-D-乳酸の混合は日本製鋼所社製TEX30型二軸押出機(L/D=45.5)を用いて行った。
(1)により得られた混合物を、真空乾燥機中、140℃にて圧力13.3Paで4時間固相重合を行い、次いで150℃に昇温して4時間、さらに160℃に昇温して10時間固相重合を行った。
(比較例6)
(1)ポリ-L-乳酸とポリ-D-乳酸を混合する工程
30gのPLA6と30gのPDA5を、200ccフラスコ中でブレンドしながら常圧で加熱し、室温から190℃まで10分間で昇温させた。昇温過程において160℃で一部の融解が確認された。その後、降温させ混合物を得た。
(1)で得られた混合物を圧力66.6Pa、110℃で2時間熱処理を行った後、130℃で5時間、140℃で25時間(合計30時間)加熱し固相重合を行った。
(比較例7)
(1)ポリ-L-乳酸とポリ-D-乳酸を混合する工程
ポリ-L-乳酸とポリ-D-乳酸の混合方法は実施例1と同様である。
L-ラクチド100部、エチレングリコール0.05部を撹拌装置のついた反応容器中で、窒素雰囲気下、150℃で均一に溶解させた後、オクチル酸錫0.003部を加え、3時間重合反応を行った。重合反応終了後、反応物をクロロホルムに溶解させ、メタノール(クロロホルムの5倍量)中で撹拌しながら沈殿させ、モノマーを完全に除去することでポリ-L-乳酸(PLA10)を得た。PLA10の重量平均分子量は20.1万、分散度は1.7、融点は173℃、融解終了温度は190℃であった。
[参考例20]
L-ラクチド100部、エチレングリコール0.1部を撹拌装置のついた反応容器中で、窒素雰囲気下、150℃で均一に溶解させた後、オクチル酸錫0.003重量部を加え、3時間重合反応を行った。その後、反応系内にリン系の触媒失活剤を0.01部添加して10分間撹拌を行い、触媒失活を行った。得られた反応物はクロロホルムに溶解させ、メタノール(クロロホルムの5倍量)中で撹拌しながら沈殿させ、モノマーを完全に除去することでポリ-L-乳酸(PLA11)を得た。PLA11の重量平均分子量は12.2万、分散度は1.7、融点は170℃、融解終了温度188℃であった。
[参考例21]
D-ラクチド100部を撹拌装置のついた反応容器中で、窒素雰囲気下、160℃で均一に溶解させた後、オクチル酸錫0.003部を加え、6時間重合反応を行った。重合反応終了後、反応物をクロロホルムに溶解させ、メタノール(クロロホルムの5倍量)中で撹拌しながら沈殿させ、モノマーを完全に除去することでポリ-D-乳酸(PDA10)を得た。PDA10の重量平均分子量は130万、分散度は1.6、融点は180℃、融解終了温度194℃であった。
[参考例22]
D-ラクチド100部,エチレングリコール0.05部を撹拌装置のついた反応容器中で、窒素雰囲気下、150℃で均一に溶解させた後、オクチル酸錫0.003部を加え、3時間重合反応を行った。重合終了後、反応物をクロロホルムに溶解させ、メタノール(クロロホルムの5倍量)中で撹拌しながら沈殿させ、モノマーを完全に除去することでポリ-D-乳酸(PDA11)を得た。PDA11の重量平均分子量は19.8万、分散度は1.7、融点は172℃、融解終了温度190℃であった。
[参考例23]
D-ラクチド100部,エチレングリコール0.1部を撹拌装置のついた反応容器中で、窒素雰囲気下、150℃で均一に溶解させた後、オクチル酸錫0.003部を加え、3時間重合反応を行った。その後、反応系内にリン系の触媒失活剤を0.01部添加して10分間撹拌を行い、触媒失活を行った。得られた反応物をクロロホルムに溶解させ、メタノール(クロロホルムの5倍量)中で撹拌しながら沈殿させ、モノマーを完全に除去することでポリ-D-乳酸(PDA12)を得た。PDA12の重量平均分子量は12.0万、分散度は1.7、融点は169℃、融解終了温度188℃であった。
(比較例8、9、11、12)
(1)ポリ-L-乳酸とポリ-D-乳酸を混合する工程
ポリ-L-乳酸とポリ-D-乳酸の混合は東洋精機製バッチ式二軸混練機(ラボプラストミル)を用いて行い、ポリ乳酸混合物を得た。試験条件は、混練温度245℃、混練回転数120rpm、混練時間は比較例8、11が10分、比較例9、12が60分である。ポリ-L-乳酸とポリ-D-乳酸の組み合わせは表2に示すとおりである。
(比較例10、13)
(1)ポリ-L-乳酸とポリ-D-乳酸を混合する工程
ポリ乳酸混合物は、比較例9、12と同様条件でバッチ式二軸混練機を用いてポリ-L-乳酸とポリ-D-乳酸を60分間混練し、混練後可塑剤を10重量部添加してさらに5分間混練することで作製した。ポリ-L-乳酸、ポリ-D-乳酸、可塑剤の組み合わせは表2に示すとおりである。
(比較例14~17)
(1)ポリ-L-乳酸とポリ-D-乳酸を混合する工程
ポリ-L-乳酸とポリ-D-乳酸の混合は、実施例1~12と同様二軸押出機を用いて混練により作製した。二軸押出機に対するポリ-L-乳酸、ポリ-D-乳酸および結晶核剤の供給に関しては、いずれも樹脂供給口から行い、混練温度は240℃に設定し、混練を行った。ポリ-L-乳酸、ポリ-D-乳酸および結晶核剤の組み合わせは表2に示すとおりである。
表3に示すとおり、実施例1~12と比較例1~6で得られたポリ乳酸ブロック共重合体(SB1~SB12、SB13~SB18)および比較例7で得られたポリ乳酸混合物(SB19)を、二軸押出機を用いてリン系触媒失活剤0.05部とともに240℃での溶融混練を行い、触媒失活を行った。続いて、240℃で2分間加熱して溶融し、その後プレス温度80℃でプレスすることで厚さ0.1mmのプレスシートを作製した。次いで、プレスシートを窒素雰囲気下、110℃で30分間の熱処理条件にて熱処理を行うことで各種測定用のシート状成形体とした。
(実施例25)
実施例1で固相重合により得られたポリ乳酸ブロック共重合体SB1について、シート成形体を作製する前に触媒失活を行った。触媒失活の方法は実施例13~24と同様である。続いて、触媒失活を行ったポリ乳酸ブロック共重合体は、240℃で2分間加熱して溶融し、その後プレス温度80℃でプレスすることで厚さ0.1mmのプレスシート作製した後、氷水中に冷却することで各種測定用のシート状成形体とした。シート状成形体の各種物性測定方法は実施例13~24と同様である。
(比較例25)
実施例1で得られたポリ乳酸混合物SC1について、シート成形体を作製する前に触媒失活を行った。触媒失活の方法は実施例13~24と同様である。続いて触媒失活したSC1を用いて各種物性測定用の成形体を作製した。成形体製造方法および物性測定方法は実施例13~24と同様である。
(比較例26、27、29、30)
比較例8、9、11、12で得られたポリ乳酸混合物(SC19、SC20、SC22、SC23)について、シート成形体を作製する前に触媒失活を行った。触媒失活の方法は実施例13~24と同様である。続いて触媒失活したポリ乳酸混合物を用いて各種物性測定用の成形体を作製した。各種物性測定用の成形体作製方法、物性測定方法は実施例13~24と同様である。
(比較例28、31)
比較例10、13で得られたポリ乳酸混合物(SC21、SC24)について、シート成形体を作製する前に触媒失活を行った。触媒失活の方法は実施例13~24と同様である。続いて触媒失活したポリ乳酸混合物を用いて各種物性測定用の成形体を作製した。各種物性測定用の成形体の製造方法および物性測定方法は実施例13~24と同様である。表3に示すとおり、各比較例のシート状成形体の相対結晶化度はいずれも100%であった。成形体のヘイズ値は、可塑剤を添加することで比較例23、25に比較して低くなり、その結果透明性が向上したが、成形体の引張強度については可塑剤添加により低下する傾向であった。
(比較例32~36)
参考例20で得られたポリ乳酸(PLA11)および比較例14~17で得られたポリ乳酸混合物(SC25~SC28)について、シート成形体を作製する前に触媒失活を行った。触媒失活の方法は実施例13~24と同様である。続いて触媒失活したポリ乳酸混合物を用いて各種物性測定用の成形体を作製した。
Claims (13)
- ポリ-L-乳酸またはポリ-D-乳酸のいずれか一方の重量平均分子量が6万~30万であり、もう一方の重量平均分子量が1万~5万であるポリ-L-乳酸とポリ-D-乳酸を混合し、重量平均分子量が9万以上、かつステレオコンプレックス形成率(Sc)が下記式(1)を満たす混合物を得る工程、次いで、混合物を混合物の融点より低い温度で固相重合する工程からなるL-乳酸単位からなるセグメントとD-乳酸単位からなるセグメントにより構成されるポリ乳酸ブロック共重合体の製造方法。
Sc=ΔHh/(ΔHl+ΔHh)×100>60 (1)
ここで、ΔHh:ステレオコンプレックス結晶に基づく熱量(J/g)、ΔHl:ポリ-L-乳酸単独結晶およびポリ-D-乳酸単独結晶の結晶融解に基づく熱量(J/g) - ポリ-L-乳酸とポリ-D-乳酸のうち、重量平均分子量の高い方と重量平均分子量の低い方の比が2以上30未満であるポリ-L-乳酸とポリ-D-乳酸を混合し、重量平均分子量が9万以上、かつステレオコンプレックス形成率(Sc)が下記式(1)を満たす混合物を得る工程、次いで、混合物を混合物の融点より低い温度で固相重合する工程からなるポリ乳酸ブロック共重合体の製造方法。
Sc=ΔHh/(ΔHl+ΔHh)×100>60 (1)
ここで、ΔHh:ステレオコンプレックス結晶に基づく熱量(J/g)、ΔHl:ポリ-L-乳酸単独結晶およびポリ-D-乳酸単独結晶の結晶融解に基づく熱量(J/g) - 原料となるポリ-L-乳酸とポリ-D-乳酸のいずれか一方の重量平均/分子量が17万以上であり、かつもう一方の重量平均分子量が2万以上である請求項1または2記載のポリ乳酸ブロック共重合体の製造方法。
- ポリ-L-乳酸とポリ-D-乳酸の混合物が下記式(2)を満たす請求項1~3いずれかに記載のポリ乳酸ブロック共重合体の製造方法。
Sc=ΔHh/(ΔHl+ΔHh)×100>70 (2) - 得られるポリ乳酸ブロック共重合体が下記式(3)を満たす請求項1~4いずれかに記載のポリ乳酸ブロック共重合体の製造方法。
Sc=ΔHh/(ΔHl+ΔHh)×100>80 (3) - 得られるポリ乳酸ブロック共重合体のDSC測定において、ポリ乳酸ブロック共重合体を250度まで昇温して3分間恒温状態にした後、冷却速度20℃/minで降温した際の降温結晶化温度が130℃以上である請求項1~5いずれかに記載のポリ乳酸ブロック共重合体の製造方法。
- 得られるポリ乳酸ブロック共重合体の重量平均分子量と数平均分子量の比で示される分散度が2.7以下である請求項1~6いずれかに記載のポリ乳酸ブロック共重合体の製造方法。
- 得られるポリ乳酸ブロック共重合体を含む成形体であって、該成形体が下記式(4)を満たし、かつ厚さ100μmの成形体としたときのヘイズ値が30%以下である請求項1~7いずれかに記載のポリ乳酸ブロック共重合体の製造方法。
相対結晶化度=[(ΔHm-ΔHc)/ΔHm]×100>90 (4)
ここで、ΔHm:成形体の結晶融解エンタルピー(J/g)、ΔHc:成形体の昇温時結晶化エンタルピー(J/g) - 混合物に含まれる触媒が、混合物100重量部に対して0.001~0.5重量部である請求項1~8いずれかに記載のポリ乳酸ブロック共重合体の製造方法。
- 混合物に含まれる触媒が錫化合物、チタン化合物、鉛化合物、亜鉛化合物、コバルト化合物、鉄化合物、リチウム化合物、希土類化合物、およびスルホン酸化合物から得られる少なくとも一種である請求項9に記載のポリ乳酸ブロック共重合体の製造方法。
- 錫化合物が、酢酸錫(II)、オクチル酸錫(II)、塩化錫(II)、塩化錫(IV)から選ばれる少なくとも一種であり、スルホン酸化合物がメタンスルホン酸、エタンスルホン酸、プロパンスルホン酸、プロパンジスルホン酸、ナフタレンジスルホン酸、および2-アミノエタンスルホン酸から選ばれる少なくとも一種である請求項10記載のポリ乳酸ブロック共重合体の製造方法。
- 固相重合時の温度を段階的または連続的に昇温する請求項1~11いずれかに記載のポリ乳酸ブロック共重合体の製造方法。
- 得られるポリ乳酸ブロック共重合体の重量平均分子量が10万以上である請求項1~12いずれかに記載のポリ乳酸ブロック共重合体の製造方法。
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US13/819,199 US9150690B2 (en) | 2010-08-31 | 2011-06-27 | Method for producing polylactic acid block copolymer |
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KR1020127032740A KR20130113332A (ko) | 2010-08-31 | 2011-06-27 | 폴리락트산 블록 공중합체의 제조 방법 |
CN201180042032.2A CN103068880B (zh) | 2010-08-31 | 2011-06-27 | 聚乳酸嵌段共聚物的制造方法 |
JP2011535342A JP5630439B2 (ja) | 2010-08-31 | 2011-06-27 | ポリ乳酸ブロック共重合体の製造方法 |
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US9150690B2 (en) | 2015-10-06 |
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JP5957885B2 (ja) | 2016-07-27 |
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US20130158209A1 (en) | 2013-06-20 |
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TW201213390A (en) | 2012-04-01 |
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