JP2016164243A - Polylactic acid resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polylactic acid resin composition having excellent heat resistance, impact resistance, and dimensional stability.SOLUTION: A polylactic acid resin composition comprises a curable resin obtained by curing a modified polylactic acid with a polymerization initiator, and a nucleating agent, where the modified polylactic acid is a polylactic acid having a polymerizable unsaturated group, and the modified polylactic acid has an optical purity of 92.0% or more.SELECTED DRAWING: None

Description

  The present invention relates to a polylactic acid resin composition.

Polylactic acid has attracted attention because it is a thermoplastic resin having biodegradability and has excellent transparency, biodegradability, and moldability.
However, polylactic acid has a problem that it is inferior in heat resistance and impact resistance. Moreover, when processing polylactic acid, the outstanding dimensional stability is requested | required.

As a method for solving such a problem, there has been proposed a method in which an impact resistance imparting agent comprising a lactic acid polyester having a weight average molecular weight of 10,000 or more and a glass transition temperature of 60 ° C. or less is mixed with polylactic acid. . According to such a method, it has been reported that impact resistance and flexibility can be imparted to polylactic acid (see, for example, Patent Document 1).
On the other hand, it has been reported that a polylactic acid resin composition containing polylactic acid and layered silicate is excellent in heat resistance and impact strength (see, for example, Patent Document 2).

  The industry demands the development of a polylactic acid composition having heat resistance, impact resistance, and dimensional stability that are superior to those of the prior art. In particular, if a polylactic acid composition having heat resistance, impact resistance and dimensional stability that can be used as automobile exterior parts can be developed, the industrial use of polylactic acid can be further expanded.

  However, none of the techniques disclosed above is sufficient in terms of heat resistance, impact resistance, and dimensional stability to be applied as an automobile exterior part or the like.

  An object of this invention is to provide the polylactic acid resin composition excellent in heat resistance, impact resistance, and dimensional stability.

Means for solving the problems are as follows.
That is, the polylactic acid resin composition of the present invention is
Containing a cured resin obtained by curing modified polylactic acid using a polymerization initiator, and a nucleating agent;
The modified polylactic acid is polylactic acid having a polymerizable unsaturated group,
The optical purity of the modified polylactic acid is 92.0% or more.

  ADVANTAGE OF THE INVENTION According to this invention, the polylactic acid resin composition excellent in heat resistance, impact resistance, and dimensional stability can be provided.

FIG. 1 is a general phase diagram showing the state of a substance with respect to temperature and pressure. FIG. 2 is a phase diagram for defining the range of the compressible fluid in the present embodiment.

(Polylactic acid resin composition)
The polylactic acid resin composition of the present invention contains at least a cured resin obtained by curing modified polylactic acid using a polymerization initiator and a nucleating agent, and further contains other components as necessary. To do.

<Curing resin>
The curable resin is obtained by curing modified polylactic acid using a polymerization initiator.

<< Modified polylactic acid >>
The modified polylactic acid is polylactic acid having a polymerizable unsaturated group.
Examples of the polymerizable unsaturated group in the modified polylactic acid include a radical polymerizable unsaturated group.

  Examples of the method for obtaining the modified polylactic acid include a method of reacting a polyester having a polymerizable unsaturated group with polylactic acid using a coupling agent (for example, polyisocyanate, polyoxazoline, polyepoxide, etc.), Examples thereof include a method obtained by polymerizing at least one of lactic acid and lactide in the presence of a saturated polyester. Among these, the method obtained by polymerizing at least one of lactic acid and lactide in the presence of unsaturated polyester is preferable in the following points. In the resulting modified polylactic acid, the degree of phase mixing between the unsaturated polyester and the polylactic acid block is improved, and polymerizable unsaturated groups can be present uniformly in the modified polylactic acid. By doing so, the volume shrinkage at the time of hardening the modified polylactic acid is further suppressed, and the dimensional stability at the time of hot melt molding is further improved.

Examples of the lactic acid used for the polymerization include L-lactic acid and D-lactic acid.
Examples of the lactide used for the polymerization include L-lactide, D-lactide, and meso lactide.

  The polymerization conditions in the method obtained by polymerizing at least one of lactic acid and lactide in the presence of the unsaturated polyester are not particularly limited and may be appropriately selected depending on the intended purpose.

-Unsaturated polyester-
The unsaturated polyester is a polyester having a polymerizable unsaturated group.
The unsaturated polyester preferably contains an unsaturated carboxylic acid and an aliphatic alcohol as constituent components.
It is preferable that the unsaturated polyester has a hydroxyl group at the terminal because the modified polylactic acid is easily obtained when at least one of lactic acid and lactide is polymerized in the presence of the unsaturated polyester.
When the modified polylactic acid is obtained by polymerizing at least one of lactic acid and lactide in the presence of the unsaturated polyester, the unsaturated polyester plays a role as a polymerization initiator.
The unsaturated polyester can be synthesized, for example, by reacting an unsaturated carboxylic acid and an aliphatic alcohol by a known method.

--Unsaturated carboxylic acid--
The unsaturated carboxylic acid is not particularly limited as long as it is a carboxylic acid having a polymerizable unsaturated group and can generate the unsaturated polyester by reacting with an aliphatic alcohol. Examples thereof include unsaturated monocarboxylic acids and unsaturated polycarboxylic acids.

Examples of the unsaturated monocarboxylic acid include monounsaturated fatty acids and polyunsaturated fatty acids.
Examples of the monounsaturated fatty acid include crotonic acid, myristoleic acid, palmitoleic acid, sapienic acid, oleic acid, elaidic acid, vaccenic acid, and nervonic acid.
Examples of the polyunsaturated fatty acid include linoleic acid, eicosadienoic acid, docosadienoic acid, α-linolenic acid, γ-linolenic acid, pinolenic acid, α-eleostearic acid, β-eleostearic acid, mead acid, Examples include arachidonic acid and sardine acid.

  Examples of the unsaturated polycarboxylic acid include unsaturated dicarboxylic acid. Examples of the unsaturated dicarboxylic acid include maleic acid, fumaric acid, glutaconic acid, muconic acid, and mesaconic acid. In obtaining the unsaturated polyester, maleic acid and fumaric acid may use acid anhydrides.

  These unsaturated carboxylic acids may be used individually by 1 type, and may use 2 or more types together.

  Among these, maleic acid or its acid anhydride is preferable from the viewpoint of high density of polymerizable unsaturated groups.

--Fatty alcohol--
The aliphatic alcohol is not particularly limited as long as it can react with the unsaturated carboxylic acid to produce the unsaturated polyester, and can be appropriately selected according to the purpose. Examples thereof include aliphatic alcohols and trihydric or higher aliphatic alcohols.

  Examples of the divalent aliphatic alcohol include ethylene glycol, propylene glycol, butanediol, heptanediol, hexanediol, octanediol, nonanediol, decanediol, 1,4-cyclohexanedimethanol, neopentyl glycol, and the like. .

  Examples of the trihydric or higher aliphatic alcohol include glycerol, sorbitol, xylitol, ribitol, erythritol, triethanolamine, and trimethylolpropane.

  These aliphatic alcohols may be used alone or in combination of two or more.

  There is no restriction | limiting in particular as a weight average molecular weight of the said unsaturated polyester, Although it can select suitably according to the objective, 1,000-10,000 are preferable and 2,000-6,000 are more preferable.

  There is no restriction | limiting in particular as a hydroxyl value of the said unsaturated polyester, Although it can select suitably according to the objective, 5 mgKOH / g-30 mgKOH / g are preferable, and 10 mgKOH / g-25 mgKOH / g are more preferable.

--Catalyst--
When polymerizing at least one of lactic acid and lactide in the presence of the unsaturated polyester, a catalyst may be used.

  Examples of the catalyst include metal catalysts and organic catalysts.

  The metal catalyst is preferably an organic catalyst containing a metal atom. Such a metal catalyst is not particularly limited, and tin compounds such as tin octylate, tin dibutyrate and di (2-ethylhexanoate) tin; aluminum compounds such as aluminum acetylacetonate and aluminum acetate; tetra Known compounds such as titanium compounds such as isopropyl titanate and tetrabutyl titanate; zirconium compounds such as zirconium isoprooxide; and antimony compounds such as antimony trioxide are used.

  What is necessary is just to adjust the addition amount of the said metal catalyst suitably according to the metal catalyst seed | species and the kind of substituent. For example, when ring-opening polymerization of lactide, the addition amount of the metal catalyst is preferably 0.005 to 0.5 parts by mass, and 0.01 to 0.2 parts by mass with respect to 100 parts by mass of lactide. Is more preferable.

  The organic catalyst is preferably a compound that functions as a basic nucleophile, more preferably a compound containing a basic nucleophilic nitrogen atom, and even more preferably a cyclic compound having a nitrogen atom. There is no restriction | limiting in particular as said compounds, According to the objective, it can select suitably, For example, cyclic | annular monoamine, cyclic diamine (For example, cyclic diamine compound etc. which have an amidine skeleton), cyclic triamine which has a guanidine skeleton. Examples thereof include a compound, a heterocyclic aromatic organic compound containing a nitrogen atom, and N-heterocyclic carbene. The cationic organic catalyst is used in the ring-opening polymerization reaction. In this case, hydrogen is extracted from the polymer main chain (back-biting), and therefore, the molecular weight distribution is widened and it is difficult to obtain a high molecular weight product.

Examples of the cyclic amine include quinuclidine.
Examples of the cyclic diamine include 1,4-diazabicyclo- [2.2.2] octane (DABCO), 1,5-diazabicyclo (4,3,0) -5-nonene.
Examples of the cyclic diamine compound having an amidine skeleton include 1,8-diazabicyclo [5.4.0] undec-7-ene (DBU) and diazabicyclononene.
Examples of the cyclic triamine compound having a guanidine skeleton include 1,5,7-triazabicyclo [4.4.0] dec-5-ene (TBD) and diphenylguanidine (DPG).
Examples of the heterocyclic aromatic organic compound containing a nitrogen atom include N, N-dimethyl-4-aminopyridine (DMAP), 4-pyrrolidinopyridine (PPY), pyrocholine, imidazole, pyrimidine, and purine. Can be mentioned.
Examples of the N-heterocyclic carbene include 1,3-di-tert-butylimidazol-2-ylidene (ITBU).

  Among these, DABCO, DBU, DPG, TBD, DMAP, PPY, and ITBU are preferable because they are less affected by steric hindrance and have high nucleophilicity or have a boiling point that can be removed under reduced pressure.

  Among these organic catalysts, for example, DBU is liquid at room temperature and has a boiling point. When such an organic catalyst is selected, the organic catalyst can be almost quantitatively removed from the polymer by subjecting the obtained polymer to a reduced pressure treatment. In addition, the kind of organic solvent and the presence or absence of a removal process are determined according to the use purpose of a product, etc.

-Optical purity-
In the modified polylactic acid, the heat denaturation temperature (heat resistance) can be improved by crystallizing the polylactic acid moiety in the modified polylactic acid. Therefore, the modified polylactic acid preferably has crystallinity. In order to crystallize the modified polylactic acid, the optical purity of the modified polylactic acid needs to be 92.0% or more. When the optical purity is less than 92.0%, the heat denaturation temperature (heat resistance) becomes insufficient.

-Weight average molecular weight-
There is no restriction | limiting in particular as a weight average molecular weight of the said modified polylactic acid, Although it can select suitably according to the objective, 100,000 or more and 600,000 or less are preferable, and 200,000 or more and 400,000 or less are more preferable. When the weight average molecular weight is within the preferred range, it is advantageous in that both the heat resistance and moldability of the polylactic acid resin composition can be achieved.

-Melting point-
There is no restriction | limiting in particular as melting | fusing point of the said modified polylactic acid, Although it can select suitably according to the objective, 170 to 220 degreeC is preferable and 180 to 200 degreeC is more preferable. When the melting point is within a preferable range, it is advantageous in that the heat distortion temperature (heat resistance) and the molding processability (suppression of thermal decomposition during the molding process) can be achieved in an excellent region.
If the modified polylactic acid is a block copolymer or a graft copolymer, the melting point of the polylactic acid is not lowered, but it is difficult to raise the melting point by random copolymerization or alternating copolymerization. The heat distortion temperature may not be expressed.

<< Polymerization initiator >>
The polymerization initiator is not particularly limited as long as it can polymerize the polymerizable unsaturated group in the modified polylactic acid, and can be appropriately selected according to the purpose. Agents are preferred.

  The radical polymerization initiator is not particularly limited as long as it can perform polymerization of the radical polymerizable unsaturated group when the polymerizable unsaturated group is a radical polymerizable unsaturated group. It can be appropriately selected depending on the purpose, and examples thereof include organic peroxides and azo compounds.

  Examples of the organic peroxide include di-t-amyl peroxide, t-butyl peroxy octoate, benzoyl peroxide, 1,1-di-t-butyl peroxy-3,3,5, trimethylcyclohexane. , T-butyl peroxyisopropyl carbonate, t-butyl peroxybenzoate, dicumyl peroxide, di-t-butyl peroxide and the like.

  Examples of the azo compound include azobisisobutylnitrile, 1,1′-azobis (cyclohexanecarbonitrile), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2′-. Azobis (2,4-dimethylvaleronitrile), dimethyl-2,2′-azobis (2-methylpropineauto), 2,2′-azobis (2-methylpropionamidine) dihydrochloride, 2,2′- Bis (2-imidazolin-2-yl) [2,2′-azobispropane] dihydrochloride and the like can be mentioned.

  These polymerization initiators may be used alone or in combination of two or more.

  Among these, organic peroxides are preferable because they are highly reactive and easily form a crosslinked body.

  There is no restriction | limiting in particular as the usage-amount of the said polymerization initiator at the time of obtaining the said cured resin, Although it can select suitably according to the objective, 0.01 mass with respect to 100 mass parts of said modified polylactic acid. Part-5 mass parts is preferable, 0.05 mass part-1 mass part is more preferable, 0.1 mass part-0.5 mass part is especially preferable.

  The cured resin is preferably obtained by curing the modified polylactic acid using the polymerization initiator in the presence of the nucleating agent in terms of improving the degree of dispersion of the nucleating agent.

  There is no restriction | limiting in particular as temperature at the time of hardening | curing the said modification | denaturation polylactic acid, Although it can select suitably according to the objective, More than the thermal decomposition temperature of the said polymerization initiator is preferable.

  There is no restriction | limiting in particular as time when hardening the said modified polylactic acid, According to the objective, it can select suitably.

<Nucleating agent>
The nucleating agent is not particularly limited as long as it imparts the action of promoting crystallization of the crystalline polymer, and known ones can be used, and examples include organic nucleating agents and inorganic nucleating agents. It is done.

  Examples of the organic nucleating agent include aliphatic esters, aliphatic amides, and fatty acid metal salts.

  Examples of the inorganic nucleating agent include silicates such as talc, smectite, bentonite, dolomite, sericite, feldspar powder, kaolin, mica, and montmorillonite.

The nucleating agent preferably satisfies at least one of the following (1) to (3).
(1) A stereocomplex crystal is formed with polylactic acid which is a constituent of the modified polylactic acid.
(2) Polylactic acid comprising an optical isomer of lactic acid constituting polylactic acid which is a constituent component of the modified polylactic acid.
(3) An organic compound containing a structure of an optical isomer of lactic acid constituting polylactic acid which is a constituent component of the modified polylactic acid.
Examples of the organic compound (3) include a lactic acid polymer having a low molecular weight, a polymer containing another type of polymer, and a part of which is polylactic acid.

Furthermore, it is more preferable that the nucleating agent satisfies the following (4) to (6).
(4) A stereocomplex crystal can be formed with the modified polylactic acid.
(5) Polylactic acid having a polymerizable unsaturated group.
(6) The polylactic acid in (5) is composed of an optical isomer of lactic acid constituting the modified polylactic acid.
The polylactic acid (5) is obtained by polymerizing at least one of lactic acid and lactide in the presence of an unsaturated polyester, and the unsaturated polyester comprises an unsaturated carboxylic acid and an aliphatic alcohol as constituent components. It is particularly preferable to contain it in the following points. The unsaturated polyester has a Tg of room temperature or lower due to its composition. Therefore, the nucleating agent has rubber-like elasticity after curing. Then, the soft component which is a rubber-like crosslinked body and the hard component of polylactic acid whose crystallization is promoted are continuously arranged, and the effect of improving the impact resistance of the entire polylactic acid resin composition can be sufficiently obtained. .
Examples of the unsaturated polyester include the unsaturated polyester exemplified in the description of the modified polylactic acid.

  There is no restriction | limiting in particular as content of the said nucleating agent in the said polylactic acid resin composition, Although it can select suitably according to the objective, With respect to 100 mass parts of polylactic acid parts in the said modified polylactic acid, 0.1 mass part-15 mass parts are preferable, 1 mass part-12 mass parts are more preferable, and 3 mass parts-10 mass parts are especially preferable. When the content is within the preferred range, it is advantageous in terms of both a crystallization promoting effect and mechanical hardness.

<Other ingredients>
Examples of the other components in the polylactic acid resin composition include surfactants, antioxidants, antifogging agents, ultraviolet absorbers, pigments, colorants, inorganic particles, various fillers, thermal stabilizers, flame retardants, Antistatic agents, surface wetting improvers, incineration aids, lubricants, natural products, mold release agents, plasticizers, and the like. If necessary, a polymerization terminator (benzoic acid, hydrochloric acid, phosphoric acid, metaphosphoric acid, acetic acid, lactic acid, etc.) can be used after the polymerization reaction for obtaining the polylactic acid or the modified polylactic acid.

  The addition amount of these additives varies depending on the purpose of addition and the type of additive, but is preferably 0 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the cured resin.

<Analysis of polylactic acid resin composition>
The molecular structure of the polylactic acid resin composition can be confirmed by X-ray diffraction, GC / MS, LC / MS, IR measurement, etc. in addition to NMR measurement by solution or solid.
An example of the separation means for each component when analyzing the polylactic acid resin composition is shown in detail.
First, 1 g of the polylactic acid resin composition is put into 100 mL of THF, and a solution having a soluble component dissolved therein is obtained while stirring for 30 minutes at 25 ° C.
This is filtered through a membrane filter having an opening of 0.2 μm to obtain a THF-soluble component of the polylactic acid resin composition.
Subsequently, this is melt | dissolved in THF, it is set as the sample for GPC measurement, and it inject | pours into GPC used for the molecular weight measurement of each above-mentioned resin.
On the other hand, a fraction collector is placed at the eluate outlet of GPC, and the eluate is collected every predetermined count, and the eluate is eluted every 5% in area ratio from the elution curve elution start (curve rise). Get.
Next, for each elution, 30 mg of sample is dissolved in 1 mL of deuterated chloroform, and 0.05% by volume of tetramethylsilane (TMS) is added as a reference substance.
The solution is filled in a 5 mm diameter glass tube for NMR measurement, and a spectrum is obtained by performing integration 128 times at a temperature of 23 ° C. to 25 ° C. using a nuclear magnetic resonance apparatus (JNM-AL400 manufactured by JEOL Ltd.). .
The composition and composition ratio of modified polylactic acid (further, unsaturated polyester, polylactic acid), nucleating agent, etc. contained in the polylactic acid resin composition can be determined from the peak integration ratio of the obtained spectrum.
For example, peak assignment is performed as follows, and the component ratio of the constituent monomer is determined from each integral ratio. The attribution of the peak is, for example,
Near 8.25 ppm: derived from benzene ring of trimellitic acid (for one hydrogen)
8.07 ppm to around 8.10 ppm: derived from benzene ring of terephthalic acid (for 4 hydrogens)
7.1 ppm to 7.25 ppm vicinity: derived from benzene ring of bisphenol A (for 4 hydrogens)
Around 6.8 ppm: derived from benzene ring of bisphenol A (for 4 hydrogens) and from double bond of fumaric acid (for 2 hydrogens)
5.2 ppm to around 5.4 ppm: methine derived from bisphenol A propylene oxide adduct (one hydrogen)
4.0-4.2 ppm vicinity: Derived from methine group of lactic acid (for one hydrogen)
4.0 ppm to around 5.0 ppm: derived from methylene of aliphatic alcohol (for two hydrogens)
3.7 ppm to around 4.7 ppm: bisphenol A propylene oxide adduct derived from methylene (for 2 hydrogens) and bisphenol A ethylene oxide adduct derived from methylene (for 4 hydrogens)
2.2 ppm to around 2.6 ppm: derived from aliphatic dicarboxylic acid methylene (for two hydrogens)
Around 1.6 ppm: derived from methyl group of bisphenol A and aliphatic alcohol (for 6 hydrogens)
Near 1.2 to 1.3 ppm: It can be derived from the methyl group of lactic acid (for 3 hydrogen atoms).

Similarly, the polylactic acid resin composition can be analyzed by pyrolysis gas chromatography. An example is shown below.
A reaction pyrolysis gas chromatograph mass spectrometry (GC / MS) method using a reaction reagent is performed. The reaction reagent used in the reaction pyrolysis GC / MS method is a 10% by mass methanol solution (manufactured by Tokyo Chemical Industry Co., Ltd.) of tetramethylammonium hydroxide (TMAH). The GC-MS device uses Shimadzu QP2010 (instrument management No. 040108Z), the data analysis software uses Shimadzu GCMSsolution, and the heating device uses Frontier Labs Py2020D.
〔Analysis conditions〕
・ Reaction pyrolysis temperature: 500 ℃
Column: Ultra ALLOY-5, L = 30 m, ID = 0.25 mm,
Film = 0.25 μm
Column heating: 50 ° C. (holding 1 minute) to 10 ° C./min to 330 ° C. (holding 11 minutes)
Carrier gas pressure: 53.6 kPa constant Column flow rate: 1.0 mL / min
・ Ionization method: EI method (70 eV)
Mass range: m / z, 29-700
Injection mode: Split (1: 100)
At this time, the optical purity of the polylactic acid segment in the polylactic acid resin composition can be measured by changing the column to be used to a chiral column.

<Measurement of optical purity>
The ratio (L / D) of L-lactic acid and D-lactic acid in the polylactic acid segment in the polylactic acid resin composition is analyzed using HPLC. The modified polylactic acid or polylactic acid resin composition is added to a mixed solvent of pure water, a 1N aqueous sodium hydroxide solution and isopropyl alcohol, and is hydrolyzed by heating and stirring at 70 ° C.
Subsequently, after filtering and removing the solid content in a liquid, it neutralizes by adding a sulfuric acid, and the aqueous solution containing L-lactic acid and / or D-lactic acid is obtained. This aqueous solution was measured by a high performance liquid chromatograph (HPLC) using a chiral ligand exchange type column SUMICHILAR OA-5000 (manufactured by Sumika Chemical Analysis Co., Ltd.), and a peak area S (L) derived from L-lactic acid. L / D is obtained from the peak area S (D) derived from D-lactic acid.

<Measurement of weight average molecular weight>
A measuring device GPC-8320 (manufactured by Tosoh Corporation) is used, and three columns of TSKgel SuperH3000, TSKgel SuperH4000, and TSKgel SuperH5000 are connected and used. The measurement is performed by the following method.
Resin prepared by stabilizing the column in a heat chamber at 40 ° C., and flowing THF as a solvent at a flow rate of 0.6 mL / min through the column at this temperature to prepare a sample concentration of 0.05% to 0.6% by mass. 10 μL of a tetrahydrofuran (THF) sample solution was injected and measured. In measuring the weight average molecular weight Mw, the number average molecular weight Mn, and the peak top molecular weight Mp, the molecular weight distribution of the sample is calculated from the relationship between the logarithmic value of the calibration curve prepared by several monodisperse polystyrene standard samples and the count number. To do. As standard polystyrene samples for preparing a calibration curve, Showa Denko Showdex STANDARD series Mw of 3710000, 1410000, 674000, 255000, 111000, 46000, 19800, 6870, 2900, 1300 are used, and the detector is RI ( A refractive index detector is used.

<Evaluation of crystallinity>
The presence or absence of crystallinity of the “polylactic acid resin composition” in the present invention can be evaluated by the presence or absence of a crystallinity peak by an X-ray diffraction method. The equipment and conditions are shown below.
〔Analysis conditions〕
XRD: Rigaku Corporation RINT-TTRIII type wide angle X-ray diffractometer X-ray source; CuKα ray tube voltage-tube current; 50 kV-300 mA
Step width; 0.02 deg.
Measurement range: 2 ° -60 °
Measurement speed: 5 deg. / Min
Slit system; 0.5 deg. -0.15 mm-0.5 deg.
Diffraction line crystal monochromator

<Measurement of melting point>
The melting point and glass transition temperature (Tg) in the present invention can be measured using, for example, a DSC system (differential scanning calorimeter) (“Q-200”, manufactured by TA Instruments). Specifically, the glass transition temperature of the target sample can be measured by the following procedure. First, about 5.0 mg of a target sample is placed in an aluminum sample container, and the sample container is placed on a holder unit and set in an electric furnace. Next, the substrate is heated from 40 ° C. to 200 ° C. at a temperature increase rate of 10 ° C./min in a nitrogen atmosphere (first temperature increase). Then, it cools to -15 degreeC with the temperature-fall rate of 10 degree-C / min from 200 degreeC, Furthermore, it heats to 200 degreeC with the temperature-rise rate of 10 degree-C / min (temperature rise 2nd time), and measures a DSC curve.
From the obtained DSC curve, the DSC curve at the second temperature rise was selected using the analysis program in the Q-200 system, and the value was read by adopting the midpoint method in the thermogram. Can be requested. Similarly, a DSC curve at the time of the second temperature rise is selected, a graph of “endothermic heat generation amount” and “temperature” is drawn, and the temperature of the peak with the largest endothermic amount is obtained as the melting point.

<Compressive fluid>
In the present invention, various steps for obtaining the polylactic acid resin composition (for example, polymerization for obtaining polylactic acid, polymerization for obtaining modified polylactic acid, reaction for obtaining a cured resin, etc.) may be performed in a compressive fluid.

The compressive fluid will be described with reference to FIGS. 1 and 2. FIG. 1 is a phase diagram showing the state of a substance with respect to temperature and pressure. FIG. 2 is a phase diagram for defining the range of the compressible fluid.
The compressible fluid means a fluid in a state existing in any of the regions (1), (2), and (3) shown in FIG. 2 in the phase diagram shown in FIG. To do.

  In such a region, it is known that the substance has a very high density and behaves differently from that at normal temperature and pressure. In addition, when a substance exists in the area | region of (1), it becomes a supercritical fluid. A supercritical fluid is a fluid that exists as a non-condensable high-density fluid in a temperature and pressure region that exceeds the limit (critical point) at which gas and liquid can coexist, and does not condense even when compressed. Further, when the substance is present in the region (2), it becomes a liquid, but in the present invention, it is obtained by compressing a substance that is in a gaseous state at normal temperature (25 ° C.) and normal pressure (1 atm). Represents liquefied gas. Further, when the substance is present in the region (3), it is in a gaseous state, but in the present invention, it represents a high-pressure gas whose pressure is 1/2 (1/2 Pc) or more of the critical pressure (Pc).

  Examples of the substance constituting the compressive fluid include carbon monoxide, carbon dioxide, dinitrogen monoxide, nitrogen, methane, ethane, propane, 2,3-dimethylbutane, and ethylene. Among these, carbon dioxide is preferable in that it has a critical pressure of about 7.4 MPa and a critical temperature of about 31 ° C., can easily create a supercritical state, and is nonflammable and easy to handle. These compressive fluids may be used alone or in combination of two or more.

  When polymerization is performed in a compressive fluid, the polymer produced is plasticized by the compressive fluid, and crystallization occurs when the polylactic acid or modified polylactic acid used in the present invention is obtained in the compressive fluid. Can be handled as a fluid at a temperature lower than the crystallization temperature of the polymer. Various reactions (modification, copolymerization, etc.) using general crystalline polylactic acid are known to be dissolved or dispersed in an organic solvent after polylactic acid polymerization, or to be carried out in a molten state. Polylactic acid dissolves only in halogen-based solvents such as chloroform and methylene chloride, and since these solvents have a boiling point that is too low, the temperature cannot be raised to the reaction temperature required for various reactions. Further, since the reaction in the molten state must be carried out at 180 ° C. or higher, polylactic acid depolymerization or main chain cleavage occurs simultaneously with various reactions, and the mechanical strength of the resulting resin may not be sufficiently developed.

(Molded body of polylactic acid resin composition)
The molded body according to the present invention is formed by molding the polylactic acid resin composition.
The molded body is excellent in impact resistance and heat resistance, and has excellent dimensional stability. For example, it is molded into particles, films, sheets, molded products, fibers, foams, etc. It is widely used in applications such as industrial materials, agricultural supplies, sanitary materials, pharmaceuticals, cosmetics, packaging materials, food containers, and medical molded products, and can also be used for automobile exterior parts and home appliance casings.

<Particle>
There is no restriction | limiting in particular as a method of shape | molding the said polylactic acid resin composition to particle | grains, According to the objective, it can select suitably, For example, a conventionally well-known grinding | pulverization method is mentioned. The particle size of the particles is not particularly limited, but is usually 1 μm or more and 50 μm or less.
Further, when the particles of the molded body are electrophotographic toners, a mixture in which a colorant and hydrophobic fine particles are mixed in a polylactic acid resin composition is prepared. The mixture may contain other additives in addition to the binder resin, the colorant, and the hydrophobic fine particles. Examples of other additives include release agents and charge control agents. The step of mixing the additives may be performed at the same time as the polymerization reaction, or may be added while melting and kneading after the polymerization reaction or after taking out the polymerization product.

<Film>
In the present embodiment, the film refers to a film obtained by molding the polylactic acid resin composition into a thin film, for example, a film having a thickness of less than 250 μm. In this embodiment, the film is produced by stretching the polylactic acid resin composition.

  In this case, the stretch molding method is not particularly limited, but a uniaxial stretch molding method applied to general-purpose plastic stretch molding, a simultaneous or sequential biaxial stretch molding method (tubular method, tenter method, etc.), etc. should be adopted. Can do.

  Film forming is usually performed in a temperature range of 150 ° C to 280 ° C. The formed film is uniaxially or biaxially stretched by a roll method, a tenter method, a tubular method or the like. The stretching temperature is usually in the range of 30 ° C to 110 ° C, preferably 50 ° C to 100 ° C. The draw ratio is usually in the range of 0.6 to 10 times in the vertical and horizontal directions, respectively. Moreover, after extending | stretching, you may perform heat processing, such as the method of spraying a hot air, the method of irradiating infrared rays, the method of irradiating a microwave, and making it contact on a heat roll.

  By such a stretch molding method, various stretched films such as a stretched sheet, a flat yarn, a stretched tape or band, a striped tape, and a split yarn can be obtained. The thickness of the stretched film is arbitrary depending on the application, but is usually 5 μm or more and less than 250 μm.

  The molded stretched film has chemical functions, electrical functions, magnetic functions, mechanical functions, friction / abrasion / lubrication functions, optical functions, thermal functions, surface functions such as biocompatibility, etc. Various purposeful secondary processing can be performed for the purpose of application. Examples of secondary processing include embossing, painting, adhesion, printing, metalizing (plating, etc.), machining, surface treatment (antistatic treatment, corona discharge treatment, plasma treatment, photochromism treatment, physical vapor deposition, chemical vapor deposition, Coating, etc.).

<Sheets and molded products>
In the present embodiment, the sheet refers to a sheet obtained by molding the polylactic acid resin composition into a thin film, for example, a sheet having a thickness of 250 μm or more. In this embodiment, a sheet | seat can be obtained by applying the manufacturing method of the conventionally well-known sheet | seat used with respect to the said polylactic acid resin composition, for example with respect to a thermoplastic resin. Such a method is not particularly limited, and examples thereof include a T-die method, an inflation method, and a calendar method. The processing conditions for processing into a sheet are appropriately determined based on the type of polylactic acid resin composition, the apparatus, and the like. For example, when the polylactic acid resin composition is processed by the T-die method, the temperature is preferably 150 ° C. or higher and 250 ° C. or lower by an extrusion molding machine having a T die attached to the outlet. Can be processed by extruding from a T die.

  In the present embodiment, the molded product refers to a product processed using a mold. The concept of the molded product includes not only a molded product as a single unit but also a product including a molded product such as a tray handle or a molded product such as a tray to which a handle is attached.

  Although the processing method is not particularly limited, it can be processed by a conventionally known thermoplastic resin method, and examples thereof include injection molding, vacuum molding, pressure molding, vacuum pressure molding, press molding, and the like. In this case, the polylactic acid resin composition can be melted and injection molded to obtain a molded product. Moreover, a molded article can also be obtained by press-molding the sheet obtained by the above production method using a molding die and imparting a shape (giving a shape). The processing conditions for shaping are appropriately determined based on the type of polylactic acid resin composition, the apparatus, and the like. For example, when the sheet of the polylactic acid resin composition of the present embodiment is molded by press molding using a molding die, the mold temperature can be set to 100 ° C. or higher and 150 ° C. or lower. When molding by injection molding, the polylactic acid resin composition heated to 150 ° C. or more and 250 ° C. or less is injected into a mold, the mold temperature is set to about 20 ° C. or more and 80 ° C. or less, and injection is performed. Processing by molding is possible.

<Fiber>
The polylactic acid resin composition can also be applied to fibers such as monofilaments and multifilaments. In this embodiment, the concept of fibers includes not only single fibers such as monofilaments, but also intermediate products composed of fibers such as woven fabrics and nonwoven fabrics, and woven fabrics and nonwoven fabrics such as masks. Product included.

In this embodiment, in the case of a monofilament, the fiber is produced by fiberizing the polylactic acid resin composition by melt spinning, cooling and stretching by a conventionally known method. Depending on the application, a coating layer may be formed on the monofilament by a conventionally known method, and the coating layer may contain an antibacterial agent, a colorant and the like. In the case of a non-woven fabric, a method of melt spinning, cooling, stretching, opening, deposition, and heat treatment by a conventionally known method can be used. The polylactic acid resin composition may contain additives such as antioxidants, flame retardants, ultraviolet absorbers, antistatic agents, antibacterial agents, and binder resins. The step of mixing the additive may be performed at the time of the polymerization reaction, or may be added while melting and kneading after the post-polymerization reaction or after taking out the polymerization product.
If the fiber obtained by this embodiment is a monofilament, it will be widely used as a fishing line, a fish net, a surgical suture, a medical material, an electrical equipment material, an automobile material, an industrial material, and the like. Moreover, if the fiber of this embodiment is a nonwoven fabric, it will be widely applied for uses such as fishery / agricultural materials, construction / civil engineering materials, interiors, automobile members, packaging materials, daily goods, and sanitary materials.

<Foam>
The foam according to this embodiment is obtained by foaming the polylactic acid resin composition. The concept of the foam includes not only a foam as a simple substance such as a foam resin but also a part having a foam such as a heat insulating material and a soundproofing agent, and a product having a foam such as a building material.
As an efficient foam production method, the polylactic acid resin composition is melted or plasticized when the polylactic acid resin composition dissolved or plasticized in a compressible fluid is reduced in temperature and depressurized. And a method of obtaining a foam by utilizing vaporization of a compressible fluid. It is believed that the pressure-reduced fluid diffuses at a rate of 10 ⁻⁵ to 10 ⁻⁶ / sec when released to the atmosphere. When the pressure is released, since the enthalpy is constant, a temperature drop may occur, and it may be difficult to control the cooling rate. Even in this case, when the elasticity of the polymer when released to the atmosphere is large, bubbles are maintained and a foam is formed.
In the case of obtaining a foam molded product, a predetermined amount of the polylactic acid resin composition dissolved or plasticized in a compressive fluid is directly injected into a molding die, decompressed, and then foamed by heat molding. Mold body molded products. Examples of the heating means include steam, conduction heat, radiant heat, and microwaves. In this case, it is preferable to perform foam molding by heating to about 100 to 140 ° C. with these heating means, and preferably heating to 110 to 125 ° C. with steam.
Moreover, the foam can also be manufactured by applying the manufacturing method of a general foamable plastic to the said polylactic acid resin composition. In this case, the strand which extruded the resin composition which mix | blended desired additives, such as a modifier and a nucleating agent, with the said polylactic acid resin composition using a general melt extruder is obtained. Next, pellets or particles are obtained from the obtained strands using a pelletizer (particle formation step). These particles or pellets are put into an autoclave and put into a gas phase or a liquid phase such as water or pure water, and any conventional use such as a dispersant, anti-fusing agent, anti-tacking agent, etc. Using this additive, a resin particle dispersion is prepared. Furthermore, foamed particles are obtained by foaming the resin particle dispersion using a volatile foaming agent (foaming step). The particles are exposed to the atmosphere, air is permeated into the particle bubbles, and moisture attached to the particles is removed as necessary (aging process). Then, the foamed particles are filled in a closed mold having small holes and slits, and heated and foamed to form a molded body in which the individual particles are fused and integrated.

Hereinafter, the present embodiment will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples.
In addition, each physical property of the polymer used by an Example and a comparative example was calculated | required as follows.

<Measurement of weight average molecular weight (Mw)>
A measuring apparatus GPC-8320 (manufactured by Tosoh Corporation) was used, and three columns of TSKgel SuperH3000, TSKgel SuperH4000, and TSKgel SuperH5000 were connected and used. The measurement was performed by the following method.
Resin prepared by stabilizing the column in a heat chamber at 40 ° C., and flowing THF as a solvent at a flow rate of 0.6 mL / min through the column at this temperature to prepare a sample concentration of 0.05% to 0.6% by mass. 10 μL of a tetrahydrofuran (THF) sample solution was injected and measured. In measuring the weight average molecular weight Mw, the number average molecular weight Mn, and the peak top molecular weight Mp, the molecular weight distribution of the sample is calculated from the relationship between the logarithmic value of the calibration curve prepared by several monodisperse polystyrene standard samples and the count number. did. As standard polystyrene samples for preparing a calibration curve, Showa Denko Showdex STANDARD series Mw of 3710000, 1410000, 674000, 255000, 111000, 46000, 19800, 6870, 2900, 1300 are used, and the detector is RI ( A refractive index detector was used.

<Measurement of optical purity>
The ratio (L / D) of L-lactic acid to D-lactic acid in the polylactic acid segment in the polylactic acid resin composition was analyzed using HPLC. The modified polylactic acid or polylactic acid resin composition was added to a mixed solvent of pure water, a 1N aqueous sodium hydroxide solution and isopropyl alcohol, and hydrolyzed by stirring at 70 ° C.
Subsequently, after filtering and removing the solid content in a liquid, the sulfuric acid was added and neutralized and the aqueous solution containing L-lactic acid and / or D-lactic acid was obtained. This aqueous solution was measured by a high performance liquid chromatograph (HPLC) using a chiral ligand exchange type column SUMICHILAR OA-5000 (manufactured by Sumika Chemical Analysis Co., Ltd.), and a peak area S (L) derived from L-lactic acid. L / D was obtained from the peak area S (D) derived from D-lactic acid.

<Melting point>
The melting point and glass transition temperature (Tg) in the present invention were measured using a DSC system (differential scanning calorimeter) (“Q-200”, manufactured by TA Instruments). Specifically, the glass transition temperature of the target sample was measured by the following procedure. First, about 5.0 mg of the target sample was placed in an aluminum sample container, and the sample container was placed on a holder unit and set in an electric furnace. Next, the sample was heated from 40 ° C. to 200 ° C. at a temperature increase rate of 10 ° C./min in a nitrogen atmosphere (first temperature increase). Thereafter, the temperature was decreased from 200 ° C. to −15 ° C. at a temperature decrease rate of 10 ° C./min, and further heated to 200 ° C. at a temperature increase rate of 10 ° C./min (second temperature increase) to measure a DSC curve.
From the obtained DSC curve, the DSC curve at the second temperature rise was selected using the analysis program in the Q-200 system, and the value was read by adopting the midpoint method in the thermogram. Asked.
Similarly, a DSC curve at the time of the second temperature increase was selected, a graph of “endothermic amount” and “temperature” was drawn, and the temperature of the peak with the largest endothermic amount was obtained as the melting point.

(Synthesis Example 1)
<Synthesis of unsaturated polyester>
In a 1 L four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple, 55 parts by mass of maleic anhydride, 45 parts by mass of 1,4-butanediol, and di (2-ethylhexanoic acid) 0.02 part by mass of tin was added and reacted at 180 ° C. for 2 hours, then the pressure was reduced to 10 torr at 175 ° C. to distill off the generated water, and unsaturated dicarboxylic acid and aliphatic alcohol used for polylactic acid modification To obtain an unsaturated polyester. The unsaturated polyester obtained had an acid value of 0.02 KOH mg / g, a hydroxyl value of 18.4 KOH mg / g, Mw of 4,800, and a chain end having a hydroxyl group.

(Synthesis Example 2)
<Synthesis of aliphatic polyester>
In a 1 L four-necked flask equipped with a nitrogen inlet tube, dehydration tube, stirrer and thermocouple, 52 parts by mass of succinic acid, 48 parts by mass of 1,4-butanediol, and di (2-ethylhexanoic acid) tin 0.02 parts by mass were added and reacted at 180 ° C. for 2 hours, then reduced to 10 torr at 175 ° C. to distill off the generated water, and produced from saturated dicarboxylic acid and aliphatic alcohol used for polylactic acid modification. Obtained aliphatic polyester. The obtained aliphatic polyester had an acid value of 0.02 KOH mg / g, a hydroxyl value of 19.1 KOH mg / g, Mw of 4,650, and the chain end was a hydroxyl group.

(Synthesis Example 3)
<Synthesis of Modified Polylactic Acid A1>
In a 1 L four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple, 1.5 parts by mass of unsaturated polyester (polymerization initiator) synthesized in Synthesis Example 1 and L-lactide 98.5 After adding part by mass and 0.02 part by mass of di (2-ethylhexanoic acid) tin and reacting at 180 ° C. for 2 hours, the pressure was reduced to 10 torr at 175 ° C. and the remaining monomer was distilled off to obtain modified polylactic acid A1. It was. The obtained modified polylactic acid A1 had a weight average molecular weight (Mw) of 302,000, a melting point of 185.4 ° C., and an optical purity of 99.5%.

(Synthesis Examples 4 to 9)
<Synthesis of Modified Polylactic Acids A2 to A7>
Modified polylactic acids A2 to 7 were synthesized in the same manner as in Synthesis Example 3 except that the blending ratio of the materials was changed as shown in Table 1 below. The results are shown in Table 1.

(Synthesis Example 10)
<Synthesis of polylactic acid>
In a 1 L four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple, 100 parts by mass of L-lactide, 0.2 parts by mass of di (2-ethylhexanoic acid) tin, and ethylene glycol 0 After adding 2 parts by mass and reacting at 180 ° C. for 2 hours, the pressure was reduced to 10 torr at 175 ° C. and the remaining monomer was distilled off to obtain unmodified polylactic acid. The obtained polylactic acid had a weight average molecular weight of 189,000, a melting point of 167.4 ° C., and an optical purity of 99.6%.

(Synthesis Example 11)
<Synthesis of Nucleator B1>
In a 1 L four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple, 100 parts by mass of D-lactide, 0.2 parts by mass of di (2-ethylhexanoic acid) tin, and ethylene glycol 1 After adding 0.0 part by mass and reacting at 180 ° C. for 2 hours, the pressure was reduced to 10 torr at 175 ° C. and the remaining monomer was distilled off to obtain a nucleating agent B1 comprising a homopolymer of poly-D-lactic acid.

(Synthesis Example B2)
<Synthesis of nucleating agent B2>
In a 1 L four-necked flask equipped with a nitrogen introducing tube, a dehydrating tube, a stirrer, and a thermocouple, 4 parts by mass of unsaturated polyester (polymerization initiator) synthesized in Synthesis Example 1, 96 parts by mass of D-lactide, and After adding 0.02 part by mass of di (2-ethylhexanoic acid) tin and reacting at 180 ° C. for 2 hours, the pressure was reduced to 10 torr at 175 ° C., and the remaining monomer was distilled off to obtain a nucleating agent B2.

Example 1
Laboplast mill (Toyo Seiki) 100 parts by mass of modified polylactic acid A1, 5 parts by mass of talc as a nucleating agent, and 0.2 parts by mass of Luperox DTA (di-t-amyl peroxide, manufactured by Arkema Yoshitsugu) as a polymerization initiator The product was mixed and reacted at 200 ° C. for 5 minutes to obtain a polylactic acid resin composition C1.

  A test piece was prepared by an injection molding machine using the obtained polylactic acid resin composition C1, and the heat distortion temperature was measured according to JISK7191-2. Furthermore, Izod impact strength was measured in accordance with JISK7110. Furthermore, the molding shrinkage was measured according to JISK7152-4. The results are shown in Table 2.

The heat distortion temperature showing heat resistance is preferably high, and when it is lower than 70 ° C., it was determined as x because it easily deformed in a high temperature environment such as in a car in summer.
-Evaluation criteria for heat distortion temperature-
◎: 100 ° C. or higher ○: 80 ° C. or higher and lower than 100 ° C. Δ: 70 ° C. or higher and lower than 80 ° C.

Since the impact test shows the impact resistance and durability of the molded product, it is preferable that the impact strength is high. If the impact strength is lower than 5 kJ / cm ² , a problem is likely to occur.
-Impact strength evaluation criteria-
◎: 15kJ / cm ² or more ○: 10kJ / cm ² or more 15kJ / cm less than ² △: 5kJ / cm ² or more 10kJ / cm ² less than ×: 5kJ / cm less than ²

The molding shrinkage rate is preferably low. If 1.5% or more, sink marks or warpage may occur, it was determined as x.
-Evaluation criteria for molding shrinkage-
◎: Less than 0.5% ○: 0.5% or more and less than 1.0% △: 1.0% or more and less than 1.5% ×: 1.5% or more

(Examples 2 to 7)
Polylactic acid resin compositions C2 to C7 were prepared in the same manner as in Example 1 except that the blending ratio of the materials was changed as shown in Table 2 below.
About the obtained polylactic acid resin composition, evaluation similar to Example 1 was performed. The results are shown in Table 2.

(Comparative Examples 1-8)
Polylactic acid resin compositions C8 to C15 were prepared in the same manner as in Example 1 except that the blending ratio of the materials was changed as shown in Table 2 below.
About the obtained polylactic acid resin composition, evaluation similar to Example 1 was performed. The results are shown in Table 2.

  Talc: First grade reagent manufactured by Wako Pure Chemical Industries, Ltd.

Aspects of the present invention are as follows, for example.
<1> A cured resin obtained by curing modified polylactic acid using a polymerization initiator, and a nucleating agent,
The modified polylactic acid is polylactic acid having a polymerizable unsaturated group,
The polylactic acid resin composition is characterized in that the optical purity of the modified polylactic acid is 92.0% or more.
<2> The polylactic acid resin composition according to <1>, wherein the nucleating agent satisfies at least one of the following (1) to (3).
(1) A stereocomplex crystal is formed with polylactic acid which is a constituent of the modified polylactic acid.
(2) Polylactic acid comprising an optical isomer of lactic acid constituting polylactic acid which is a constituent component of the modified polylactic acid.
(3) An organic compound containing a structure of an optical isomer of lactic acid constituting polylactic acid which is a constituent component of the modified polylactic acid.
<3> The polylactic acid resin composition according to any one of <1> to <2>, wherein the nucleating agent satisfies the following (4) to (6).
(4) A stereocomplex crystal can be formed with the modified polylactic acid.
(5) Polylactic acid having a polymerizable unsaturated group.
(6) The polylactic acid in (5) is composed of an optical isomer of lactic acid constituting the modified polylactic acid.
However, the polylactic acid (5) is obtained by polymerizing at least one of lactic acid and lactide in the presence of an unsaturated polyester, and the unsaturated polyester constitutes an unsaturated carboxylic acid and an aliphatic alcohol. Contains as a component.
<4> The polymerization initiator is a radical polymerization initiator,
The polylactic acid resin composition according to any one of <1> to <3>, wherein the polymerizable unsaturated group in the modified polylactic acid is a radically polymerizable unsaturated group.
<5> The polylactic acid resin composition according to any one of <1> to <4>, wherein the modified polylactic acid is obtained by polymerizing at least one of lactic acid and lactide in the presence of an unsaturated polyester. .
<6> The polylactic acid resin composition according to <5>, wherein the unsaturated polyester contains an unsaturated carboxylic acid and an aliphatic alcohol as constituent components.
<7> The poly according to any one of <1> to <6>, wherein the cured resin is obtained by curing the modified polylactic acid using the polymerization initiator in the presence of the nucleating agent. It is a lactic acid resin composition.
<8> The polylactic acid resin composition according to any one of <1> to <7>, wherein the modified polylactic acid has a melting point of 170 ° C. or higher and 220 ° C. or higher.
<9> The polylactic acid resin composition according to any one of <1> to <8>, wherein the modified polylactic acid has a weight average molecular weight of 100,000 to 600,000.

JP 2001-335623 A JP 2002-363393 A

Claims (9)

Containing a cured resin obtained by curing modified polylactic acid using a polymerization initiator, and a nucleating agent;
The modified polylactic acid is polylactic acid having a polymerizable unsaturated group,
The polylactic acid resin composition, wherein the optical purity of the modified polylactic acid is 92.0% or more. The polylactic acid resin composition according to claim 1, wherein the nucleating agent satisfies at least one of the following (1) to (3).
(1) A stereocomplex crystal is formed with polylactic acid which is a constituent of the modified polylactic acid.
(2) Polylactic acid comprising an optical isomer of lactic acid constituting polylactic acid which is a constituent component of the modified polylactic acid.
(3) An organic compound containing a structure of an optical isomer of lactic acid constituting polylactic acid which is a constituent component of the modified polylactic acid. The polylactic acid resin composition according to claim 1, wherein the nucleating agent satisfies the following (4) to (6).
(4) A stereocomplex crystal can be formed with the modified polylactic acid.
(5) Polylactic acid having a polymerizable unsaturated group.
(6) The polylactic acid in (5) is composed of an optical isomer of lactic acid constituting the modified polylactic acid.
However, the polylactic acid (5) is obtained by polymerizing at least one of lactic acid and lactide in the presence of an unsaturated polyester, and the unsaturated polyester constitutes an unsaturated carboxylic acid and an aliphatic alcohol. Contains as a component. The polymerization initiator is a radical polymerization initiator;
The polylactic acid resin composition according to any one of claims 1 to 3, wherein the polymerizable unsaturated group in the modified polylactic acid is a radically polymerizable unsaturated group.   The polylactic acid resin composition according to any one of claims 1 to 4, wherein the modified polylactic acid is obtained by polymerizing at least one of lactic acid and lactide in the presence of an unsaturated polyester.   The polylactic acid resin composition according to claim 5, wherein the unsaturated polyester contains an unsaturated carboxylic acid and an aliphatic alcohol as constituent components.   The polylactic acid resin composition according to any one of claims 1 to 6, wherein the cured resin is obtained by curing the modified polylactic acid using the polymerization initiator in the presence of the nucleating agent.   The polylactic acid resin composition according to any one of claims 1 to 7, wherein a melting point of the modified polylactic acid is 170 ° C or higher and 220 ° C or higher.   The polylactic acid resin composition according to any one of claims 1 to 8, wherein the modified polylactic acid has a weight average molecular weight of 100,000 to 600,000.