JP2010150384A - Polylactic acid resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polylactic acid resin composition that can improve the crystallization speed and the crystallinity of the polylactic acid, retains excellent transparency and is excellent in bleed resistance, impact resistance, heat resistance and mold processability, to provide a molded article of a polylactic acid resin using the resin composition and to provide a method for producing the molded article. <P>SOLUTION: The polylactic acid resin composition includes (A) a polylactic acid, (B) a polylactic acid block copolymer and (C) a specific trimesic acid triamide compound. The block copolymer (B) is composed of (D) a structural unit other than the polylactic acid structural unit and (E) a polylactic acid structural unit originated from a lactic acid being in optical isomeric relation to the lactic acid constituting the polylactic acid (A). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a polylactic acid resin composition that can be used in fields such as food packaging, which has excellent heat resistance, transparency, impact resistance, and moldability.

  Polylactic acid is generally attracting attention as an environmentally friendly molding resin because it can be mass-produced from plants such as corn and sugarcane as a starting material and has excellent transparency and biodegradability. Polylactic acid is expected to expand its use in many fields because it is registered in the positive list established by the Sanitation Council for Polyolefins, which is now becoming the standard in the food packaging field.

  On the other hand, polylactic acid has drawbacks in terms of performance such as impact resistance, heat resistance, and slow crystallization speed. For example, in packaging containers, deformation during transportation and storage, high temperatures such as heat sterilization and microwave oven applications. There are issues such as expansion into the field of use and molding cycleability, which is a major obstacle to the development of the polylactic acid market. Therefore, there is a strong demand from the industry to improve the above-mentioned defects without impairing the excellent rigidity inherent in polylactic acid.

  As one of the methods for improving the heat resistance of the polylactic acid, it can be improved by increasing the crystallization of the polylactic acid. That is, it can be expected that the heat resistance is improved by increasing the crystallization rate of polylactic acid to have a high crystallinity.

  Generally, when polylactic acid is crystallized, the mold temperature is set in the vicinity of the crystallization peak temperature of polylactic acid, that is, in the range of 90 ° C. or higher, particularly in the range of 100 to 140 ° C. Can be raised to a certain extent, but the molded product is softened). For example, the mold may be held for a long time or may be annealed after molding to crystallize. However, a long cooling process at the time of molding is not practical and crystallization tends to be insufficient, and post-crystallization by annealing is deformed in the process of crystallizing the molded product, so dimensional stability However, there were defects such as cracks and cracks in practical use. A further major drawback is that the transparency is remarkably deteriorated by crystallization.

Therefore, conventionally, as a method for increasing the crystallization rate of polylactic acid, a method of adding an inorganic or organic additive, that is, a crystal nucleating agent has been studied. Examples of polylactic acid using an inorganic crystal nucleating agent include those containing polylactic acid and aliphatic polyester having a melting point other than polylactic acid of 100 to 250 ° C. and a weight average molecular weight of 30,000 to 500,000 and crystals. A heat-resistant resin composition containing conductive SiO ₂ is mentioned (for example, see Patent Documents 1 and 2). However, although talc, silica, etc. are actually used as a nucleating agent for the lactic acid polymer, injection molding is attempted, but the crystallization rate is still slow, and the resulting molded product is brittle. It was hard to say.

  In addition, a lactic acid polyester composition in which an amide crystal nucleating agent is added to a polylactic acid stereocomplex is disclosed (for example, see Patent Document 3). Furthermore, as what uses the organic crystal nucleating agent for polylactic acid, the polylactic acid-type resin composition containing polylactic acid and the specific trimesic acid triamide compound is mentioned, for example (for example, refer patent document 4). .) However, this polylactic acid-based resin composition still has a slow crystallization rate in molding such as injection molding and vacuum molding, and is still insufficient for obtaining mold reproducibility and a molding cycle at a practical level. In addition, the decrease in transparency due to crystallization was not improved, and there was a problem in terms of both transparency and heat resistance.

  On the other hand, for the purpose of promoting the brittleness and crystallization speed of polylactic acid, a container for raising seedlings made of a polyester polymer containing lactic acid as a main component has been disclosed (for example, see Patent Document 5). For the purpose of solving impact resistance, polylactic acid-based polymer block copolymer or / and low glass transition temperature suitable for mixing, for example, impact resistance by using aliphatic polyester such as polycaprolactone, polyethylene adipate, etc. Although improvements are being made, the compatibility between these aliphatic polyesters and polylactic acid is insufficient, so it has not reached the level that can be applied to bleed and various molded products that can withstand practical use. I cannot expect an effect.

  On the other hand, for the purpose of improving the performance of polylactic acid, studies on copolymerizing polylactic acid with other resins and the like are also in progress. For example, a block copolymer having a polyhydroxycarboxylic acid structural unit and a polyester structural unit derived from a dicarboxylic acid and a diol, and one of the structural units of the polyhydroxycarboxylic acid structural unit and the polyester structural unit A specific molding resin having a microphase-separated structure in which the other structural unit forms a domain in the matrix formed by the resin, a polylactic acid resin composition containing the molding resin and polyhydroxycarboxylic acid, and those It is known that a molded article such as a film obtained by molding the film is excellent in flexibility, impact resistance, biodegradability, and transparency (see, for example, Patent Document 6). However, no significant effect has been observed in terms of promoting crystallization.

  Recently, it has been found that a molding resin having one glass transition temperature among the molding resins has an effect of increasing the crystallization speed while suppressing bleeding. As the molding resin, “Plamate PD-350” (hereinafter abbreviated as “PD350”) manufactured by DIC Corporation is commercially available. Here, for example, a differential scanning calorimeter (hereinafter abbreviated as “DSC”) of a blend obtained by adding Puramate PD350 to polylactic acid “Lacia H400” (hereinafter abbreviated as “PLA”) manufactured by Mitsui Chemicals, Inc. Table 1 shows the results of the isothermal crystallization time at 100 ° C. measured using. An example of a molding resin having two glass transition temperatures is “Plamate PD-150” manufactured by DIC Corporation.

  From Table 1, the molding resin having one glass transition temperature has the effect of improving the crystallization rate of polylactic acid with the addition amount, and has the effect of promoting crystallization than the molding resin having two glass transition temperatures. I understand. However, this effect is not sufficient in practical use.

  In addition, a polylactic acid resin composition in which a plasticizer is further used in combination with a system using a specific acid amide as an organic crystal nucleating agent for the polylactic acid has been studied (for example, see Patent Document 7). However, when these are actually molded by injection molding, vacuum molding, etc., the crystallization speed is certainly high, but it is still slow, which is still insufficient to obtain mold reproducibility and a practical level molding cycle. The level of transparency is also insufficient. Furthermore, bleeding of low-molecular plasticizers is also a major issue when using molded products.

  In addition, attempts have been made to use a polylactic acid stereocomplex as a nucleating agent, but although it has an effect of increasing the crystallization speed, it has not reached a practical level and is insufficient in terms of improvement of transparency (for example, (See Patent Document 8).

  Furthermore, a polylactic acid composition comprising a polylactic acid and a copolymer consisting of a polylactic acid segment that is optically isomerized with the polylactic acid and a nucleating agent and a nucleating agent has been reported, but this also promotes crystallization and ensures transparency. Is insufficient (see, for example, Patent Document 9).

Japanese Patent No. 335964 Japanese Patent No. 3599533 JP 2004-359828 A Japanese Patent No. 3671547 Japanese Patent No. 3687171 JP 2004-250663 A International Publication WO2003 / 042302 JP 2005-290257 A JP 2004-359828 A

  The problem to be solved by the present invention is to improve the crystallization speed and crystallinity of polylactic acid and maintain excellent transparency, bleed resistance, impact resistance, heat resistance, molding processing It is providing the polylactic acid resin composition excellent also in the property, the polylactic acid resin molded object using the said resin composition, and its manufacturing method.

  As a result of diligent research to solve the above-mentioned problems, the present inventors have found that polylactic acid has a polylactic acid-derived polylactic acid structural unit that has optical isomerism with lactic acid constituting the polylactic acid. It has been found that a polylactic acid resin composition to which a block copolymer is added and a specific trimesic acid triamide compound is added can solve the above-mentioned problems, and the present invention has been completed.

  That is, the present invention relates to a polylactic acid resin composition comprising polylactic acid (A), a polylactic acid block copolymer (B), and a trimesic acid triamide compound (C) represented by the following general formula (1). A polylactic acid structure derived from lactic acid, wherein the block copolymer (B) has a structural unit (D) other than a polylactic acid structural unit and lactic acid constituting the polylactic acid (A) in an optical isomerism relationship. A polylactic acid resin composition comprising the unit (E), a polylactic acid resin molded article using the resin composition, and a method for producing the same are provided.

〔一般式（１）中のＲ^１、Ｒ^２及びＲ^３は、それぞれ独立に、炭化水素基を表す。〕

[R ¹ , R ² and R ³ in the general formula (1) each independently represent a hydrocarbon group. ]

  The polylactic acid resin composition of the present invention can improve the crystallization speed and crystallinity of polylactic acid, and can maintain excellent transparency even in that case, and also has bleed resistance and impact resistance. For example, it can be applied to a wide range of fields such as transparent heat-resistant packaging containers.

  Examples of the polylactic acid (A) used in the present invention include L-polylactic acid, D-polylactic acid, D, L-polylactic acid, a mixture thereof, and a stereo stereo complex.

  The D, L-polylactic acid is a copolymer of L-lactic acid or L-lactide and D-lactic acid or D-lactide, and particularly the proportion of structural units derived from L-lactic acid or L-lactide or D -It is preferable to use what the ratio of the structural unit derived from lactic acid or D-lactide is 90 mass% or more, and it is more preferable to use what is 95 mass% or more. By using this D, L-polylactic acid, a polylactic acid resin composition excellent in heat resistance and molding processability can be obtained.

  The ratio of the L-form and D-form (optical isomer ratio) constituting the D, L-polylactic acid is determined by performing high performance liquid chromatography equipped with an optical isomer separation column on lactic acid obtained by hydrolyzing it. It can be determined by separating the L-lactic acid and D-lactic acid and then quantifying them. Examples of the hydrolysis method include a method in which D, L-polylactic acid and a sodium hydroxide / methanol mixed solution are mixed using a water bath soaker set at 65 ° C., for example. In quantification using high performance liquid chromatography, it is preferable to use one that has been previously neutralized with a diluted hydrochloric acid solution or the like.

  Moreover, as said polylactic acid (A), from a viewpoint of maintaining favorable moldability and mechanical characteristics, molecular weight is converted into standard polystyrene by gel permeation chromatography (hereinafter abbreviated as “GPC”). It is preferable to use those having a weight average molecular weight in the range of 50,000 to 400,000, and it is more preferable to use those having a weight average molecular weight in the range of 100,000 to 400,000.

  The GPC uses, for example, a gel permeation chromatography measuring device (“HLC-8220” manufactured by Tosoh Corporation), and includes two TSK gel SuperHZM-M and two TSK gel SuperHZ-2000 as columns. The measurement can be performed using TSK SuperH-H as a guard column and tetrahydrofuran as a developing solvent.

  The polylactic acid (A) can be produced by, for example, a condensation polymerization method of lactic acid or a ring-opening polymerization method of lactide which is a cyclic dimer of lactic acid. The polycondensation reaction of lactic acid is a method of esterifying a carboxyl group and a hydroxyl group of lactic acid, for example, a method of azeotropic dehydration of L-lactic acid, D-lactic acid or a mixture thereof in the presence of a high boiling point solvent under reduced pressure Is mentioned. The ring-opening polymerization method using the lactide is a method in which the ring-opened lactides are esterified with each other. For example, L-lactide or D-lactide is opened in the presence of a polymerization regulator and a polymerization catalyst. The method of letting it be mentioned. Further, D, L-lactide, which is a dimer of L-lactic acid and D-lactic acid, may be used in combination as long as the object of the present invention is achieved.

  In the present invention, the polylactic acid (A) includes at least one hydroxy group selected from the group consisting of glycolic acid having strength and toughness, caprolactone having flexibility, hydroxybutyrate having a high plant content, and hydroxyvalerate. A combined use of a carboxylic acid-derived polymer and polylactic acid, or a combined polymer of each hydroxycarboxylic acid copolymer (random or block) and polylactic acid can also be preferably used. Examples of the copolymer include a polymer of glycolic acid and lactic acid, and a polymer of lactide and caprolactone. Here, the plant degree means mass% (volume% may be specified) of plant-derived raw materials in products, commodities, and plastics. For example, a plant degree of 100% means a plastic produced from plant-derived materials.

  The polylactic acid block copolymer (B) used in the present invention promotes crystallization of the polylactic acid (A) and imparts flexibility, impact resistance, heat resistance, and moldability. Furthermore, the polylactic acid structural unit (E) constituting the polylactic acid copolymer (B) is a polylactic acid structural unit derived from lactic acid having an optical isomerism relationship with the lactic acid constituting the polylactic acid (A). Therefore, it is considered that a stereocomplex interaction occurs between the polylactic acid (A) and the polylactic acid block copolymer (B) in the polylactic acid resin composition of the present invention. In addition, the polylactic acid block copolymer (B) is a trimesic acid triamide compound even when a polylactic acid block copolymer having a polylactic acid structural unit (E) that is not related to normal optical isomerism as a constituent unit is used. The action of (C) as a dispersion aid and the action of the polylactic acid block copolymer itself as a crystal nucleating agent, promoting the crystallization of polylactic acid (A) and increasing the crystal size are recognized. Yes. On the other hand, the polylactic acid block copolymer (B) used in the present invention is expected to have the above-described function higher when a stereocomplex interaction is added. Crystallization is promoted and heat resistance is imparted, and at the same time, a molded product having higher transparency is obtained.

  As the polylactic acid block copolymer (B) used in the present invention, any of various polylactic acid block copolymers can be used without limitation, but as a structural unit (D) other than the polylactic acid structural unit, Have a polyester structural unit and a polyether structural unit, and a polyester structural unit (D ′) is preferred.

  The structure of the polyester structural unit (D ′) is not particularly limited, and is a polyester structural unit obtained by reacting diol and dicarboxylic acid, a polyester structural unit obtained by reacting diol, dicarboxylic acid and hydroxycarboxylic acid, or a lactone. Polyester structural units obtained by the ring-opening polymerization can be used.

  Among these, the polyester structural unit obtained by esterifying diol (d1) and dicarboxylic acid (d2) and / or the reaction of diol (d1), dicarboxylic acid (d2) and hydroxycarboxylic acid (d3) The polyester structural unit obtained by making it preferable is preferable.

  As the polyester structural unit (D ′), those having a weight average molecular weight in the range of 5,000 to 300,000 are preferable, and in order to obtain transparency of the obtained polylactic acid composition, 10,000 to 100,000. In order to improve the molding processability of the obtained polylactic acid composition, it is more preferable to use one having a range of 15,000 to 50,000.

  Examples of the diol (d1) that can be used when the polyester structural unit (D ′) is produced include aliphatic diols and aromatic diols. Among them, aliphatic diols are preferably used.

  Examples of the aliphatic diol include ethylene glycol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6 -Hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,4- Cyclohexanedimethanol, propylene glycol, neopentyl glycol, 3,3-diethyl-1,3-propanediol, 3,3-dibutyl-1,3-propanediol, 1,2-pentanediol, 1,3-pentanediol 2,3-pentanediol, 2,4-pentanediol, 2-methyl-2,4-penta Diol, 3-methyl-1,5-pentanediol, 1,4-pentanediol, 1,2-hexanediol, 1,3-hexanediol, 1,4-hexanediol, 1,5-hexanediol, n-butoxy Ethylene glycol, cyclohexane dimethanol, hydrogenated bisphenol A, dimer diol, diethylene glycol, dipropylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, hexylene glycol and the like can be used.

  Moreover, as said aromatic diol, the ethylene oxide addition product, propylene oxide addition product, etc. of bisphenol A can be used, for example.

  As the diol (d1), use of a diol having a branched alkyl group such as propylene glycol or 2-methyl-1,3-propanediol improves the flexibility of the polylactic acid resin composition of the present invention. This is preferable.

  Further, as the diol (d1), two or more kinds of the aliphatic diols can be used in combination, and examples thereof include use of propylene glycol and polyethylene glycol, use of ethylene glycol and 1,4-butanediol, and the like.

  In addition, the diol (d1) can be used in combination with a hydroxyl group-containing compound other than the diol within the scope of achieving the object of the present invention. For example, glycerin, trimethylolpropane, polyglycerin, pentaerythritol and the like are used. be able to.

  As the dicarboxylic acid (d2) that can be used when the polyester structural unit is produced, an aliphatic dicarboxylic acid or an aromatic dicarboxylic acid can be used.

  Examples of the aliphatic dicarboxylic acid include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, cyclohexanedicarboxylic acid, dimer acid, and fumaric acid. it can. As the aromatic dicarboxylic acid, phthalic acid, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, or the like can be used. As the dicarboxylic acid, two or more kinds of those described above can be used in combination, and examples thereof include a combination of terephthalic acid and adipic acid, a combination of sebacic acid and dimer acid, and the like.

  The method for producing the polyester structural unit (D ′) is not particularly limited. For example, the diol (d1), the dicarboxylic acid (d2), and the anhydride or esterified product thereof are esterified as necessary. It can manufacture by esterifying with a various esterification reaction using a catalyst. At that time, in order to suppress coloring of the polyester structural unit, an antioxidant such as a phosphite compound is preferably added to the total amount of the diol and the dicarboxylic acid, its anhydride or its esterified product. Up to 2000 ppm may be used.

  As the esterification catalyst, a catalyst comprising at least one metal selected from the group consisting of Groups 2, 3, and 4 of the periodic table and an organometallic compound can be preferably used. Examples of the esterification catalyst include metals such as titanium, tin, zinc, aluminum, zirconium, magnesium, hafnium, germanium, titanium tetraisopropoxide, titanium tetrabutoxide, titanium oxyacetylacetonate, tin octoate, 2 -Metal compounds such as ethyl hexane tin, acetylacetonate zinc, zirconium tetrachloride, zirconium tetrachloride tetrahydrofuran complex, hafnium tetrachloride, hafnium tetrachloride, hafnium tetrachloride complex, germanium oxide, tetraethoxygermanium, and the like can be used.

  Further, the amount of the esterification catalyst used is usually an amount that can control the reaction between the diol (d1) and the dicarboxylic acid (d2) and the like and can obtain a good hue and the like. The total amount of diol (d1) and dicarboxylic acid (d2) is preferably in the range of 10 to 1000 ppm, more preferably in the range of 20 to 800 ppm, and in the range of 30 to 500 ppm. From the viewpoint of suppressing the deterioration of the hue of the polyester structural unit (D ′).

  The esterification catalyst may be added when starting raw materials such as the diol (d1) and the dicarboxylic acid (d2), or may be added at the start of pressure reduction.

  Further, the esterification catalyst can be deactivated by various methods after the production of the polyester structural unit (D ′) to suppress side reactions when producing the polylactic acid block copolymer (B). To preferred. As a method for deactivating the esterification catalyst, for example, there is a method using a chelating agent.

  As the chelating agent, various organic chelating agents or inorganic chelating agents can be used. Examples of organic chelating agents include amino acids, phenols, hydroxycarboxylic acids, diketones, amines, oximes, phenanthrolines, pyridine compounds, dithio compounds, diazo compounds, thiols, porphyrins, and N as a coordination atom. Containing phenols and carboxylic acids can be used. As the inorganic chelating agent, for example, phosphorus compounds such as phosphoric acid, phosphoric acid ester, phosphorous acid, and phosphorous acid ester can be used.

  The temperature for producing the polyester structural unit (D ′) is preferably in the range of 150 ° C. to 260 ° C., more preferably in the range of 180 ° C. to 240 ° C. The reaction time for producing the polyester (d) is preferably 2 hours or more, and more preferably in the range of 4 to 60 hours. The degree of vacuum when producing the polyester (d) is preferably 1333 Pa or less, and more preferably 267 Pa or less.

  The polyester structural unit (D ′) is a polyester structural unit obtained by increasing the molecular weight by reacting the polyester structural unit obtained by the above method with an acid anhydride, a polyvalent isocyanate, a peroxide, or the like. Can be used within the range not impairing the present invention.

  Further, the hydroxycarboxylic acid (d3) that can be used for producing the polyester structural unit (D ′) is not particularly limited as long as it is a compound having one hydroxyl group and a carboxyl group in the molecule. , Lactic acid, glycolic acid, 2-hydroxy-n-butyric acid, 2-hydroxycaproic acid, 2-hydroxy3,3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, 2-hydroxyisocaproic acid, p-hydroxybenzoic acid Acids or mixtures thereof can be used. When a hydroxycarboxylic acid having an optical isomer is used as the hydroxycarboxylic acid, any of D-form, L-form, and racemate can be used. Moreover, as said hydroxycarboxylic acid (d3), a solid or liquid thing may be used, and those aqueous solution may be used.

  As the hydroxycarboxylic acid (d3), use of lactic acid or glycolic acid is easy to obtain, the reaction control in producing the polyester structural unit is easy, a polyester dimer, This is preferable because generation of by-products such as trimers can be significantly suppressed. Further, by using the hydroxycarboxylic acid (d3), the generation of by-products can be significantly suppressed, and the molecular weight of the obtained polyester can be easily adjusted to a relatively high molecular weight.

  The polyester structural unit comprising the diol (d1), dicarboxylic acid (d2) and hydroxycarboxylic acid (d3) uses the hydroxycarboxylic acid (d3) in addition to the diol (d1) and dicarboxylic acid (d2) as a raw material. Except for the above, it can be produced by the same method as the polyester structural unit comprising the diol (d1) and the dicarboxylic acid (d2).

  The polyester structural unit (D ′) preferably has a structural unit derived from hydroxycarboxylic acid (d3) in the range of 1 to 50 mol%, based on the entire polyester structural unit, and 3 to 40 mol%. More preferably, it is the range. By using a polyester structural unit having a structural unit derived from the hydroxycarboxylic acid (d3) in the above range, it is possible to obtain a polylactic acid resin composition that hardly causes bleeding, and has excellent crystallization speed and molding processability. it can.

  In the present invention, the polylactic acid structural unit (E) is derived from polylactic acid composed of lactic acid that forms polylactic acid (A) and lactic acid that forms optical isomerism among polylactic acids similar to polylactic acid (A). A structural unit. That is, the polylactic acid structural unit (E) constituting the polylactic acid block copolymer (B) and the polylactic acid (A) have an optical isomerism relationship with each other.

  When the polyester structural unit (D ′) is Y and the polylactic acid structural unit (E) is X, the polylactic acid block copolymer (B) is, for example, an XY block copolymer or an XYX block copolymer. It has a structure represented by a polymer and a random block copolymer. In the present invention, a mixture of block copolymers having different chemical structures other than those described above can also be used.

  The polylactic acid block copolymer (B) includes a mass ratio [D ′ / of the polyester structural unit (D ′) and the polylactic acid structural unit (E) constituting the block copolymer (B). E] is preferably in the range of 15/85 to 85/15, and in the range of 30/70 to 70/30, it is excellent in crystallization speed and crystallinity. It is preferable for obtaining a polylactic acid resin composition having bleed resistance.

  The molecular weight of the polylactic acid structural unit (E) used in the present invention is not particularly limited as long as it does not impair the effects of the present invention. However, from the viewpoint that the resulting polylactic acid block copolymer (B) can impart the characteristics of the present invention, the weight average molecular weight by the GPC method is preferably in the range of 500 to 400,000, and 5,000. The range of ˜400,000 is more preferred, the range of 10,000 to 400,000 is more preferred, the range of 10,000 to 300,000 is particularly preferred, and the range of 15,000 to 250,000 is most preferred.

  The polyester structural unit (D ′) constituting the polylactic acid block copolymer (B) may be crystalline or non-crystalline, but the impact resistance of the resulting polylactic acid resin composition In order to obtain a polylactic acid resin composition having excellent properties, transparency, flexibility, heat resistance, and moldability, it is preferably non-crystalline.

  On the other hand, the polylactic acid structural unit (E) constituting the polylactic acid block copolymer (B) is crystalline if it retains the optical isomerism relationship and has the ability to form a stereocomplex. Although it may be non-crystalline, it is preferably non-crystalline for obtaining a polylactic acid resin composition having particularly excellent impact resistance, transparency and moldability.

  The crystallinity referred to in the present invention means that the melting point is observed when DSC measurement is performed at a heating rate of 20 ° C./min, and the non-crystalline property means that the melting point is not observed by the measurement. Say.

  Amorphousness is usually obtained by selecting molecular chain constituent units that are difficult to take regular arrangement, while crystallinity is usually obtained by regularly arranging the molecular chains. For example, in the case of a polyester structure, a diol or dicarboxylic acid having a side chain, an odd number of carbon atoms, a low objectivity, or a diol or dicarboxylic acid having a different structure may be used in combination. It will be higher than if it is not. In the case of a polyhydroxycarboxylic acid structure, even when the same type of monomer is used in combination with a monomer having different optical activity, or when a monomer having a different structure is used in combination, the crystal structure collapses and the amorphous property increases.

  Moreover, as said polylactic acid-type block copolymer (B), it is preferable to use what has the range of the weight average molecular weights 10,000-300,000, and a weight average molecular weight 15, from a compatible viewpoint. Those having a range of 000 to 200,000 are more preferable, and those having a weight average molecular weight of 20,000 to 100,000 are particularly preferable in order to obtain transparency. By using a polylactic acid block copolymer having a weight average molecular weight in the above range, a polylactic acid resin composition excellent in impact resistance, transparency, flexibility and bleed resistance can be obtained.

  As the polylactic acid block copolymer (B), it is preferable to use one having a glass transition temperature (Tg) by DSC measurement in accordance with JIS K 7122 in the range of -80 to 70 ° C. In order to improve the crystallization rate and crystallinity of lactic acid, it is preferable to use one having one in the range of -20 to 60 ° C. That one glass transition temperature is observed within the temperature range means that the polyester structural unit (D ′) and the polylactic acid structural unit (E) constituting the polylactic acid block copolymer are compatible. By using such a polylactic acid block copolymer (B), a polylactic acid resin composition having an excellent crystallization speed can be obtained. As a mechanism excellent in the crystallization rate, it is estimated as follows. The polylactic acid block copolymer (B) finely dispersed in the polylactic acid matrix is a polynuclear crystal nucleus and the nucleus growth rate is increased, or the polylactic acid crystal structure is the polylactic acid block. It is presumed that the crystallization speed was increased by plasticizing with the copolymer (B) and disturbing the higher order structure.

  Moreover, as another method for measuring the glass transition temperature (Tg) of the polylactic acid block copolymer (B), the polylactic acid resin composition of the present invention containing the polylactic acid block copolymer (B) is used. When the dynamic viscoelasticity of a film obtained by processing is measured under measurement conditions of a measurement frequency of 1 Hz and a heating rate of 3 ° C./min according to, for example, JIS K 7198, a peak maximum value of loss tangent appears. Here, since the peak maximum value of the loss tangent may be defined as the glass transition temperature (Tg), it may be the glass transition temperature (Tg) of the polylactic acid-based block copolymer (B). In this case, depending on the processing conditions, for example, the dynamic viscoelasticity of a film obtained by uniaxial or biaxial stretching is measured according to, for example, JIS K 7198, with a measurement frequency of 1 Hz and a heating rate of 3 ° C./min. When measured under the measurement conditions, two peak maximum values of loss tangent appear. This means that the polylactic acid resin composition was phase-separated by the external force of stretching, and this peak maximum value corresponds to the glass transition temperature (Tg), and the polyester structural unit (D ′) And corresponding to each of the polylactic acid structural units (E).

  Next, the said polylactic acid-type block copolymer (B) can be manufactured by the following methods 1-3, for example.

  The polylactic acid block copolymer (B) is prepared by melt-mixing the polyester structural unit (D ′) and the polylactic acid structural unit (E), and then adding an esterification catalyst and performing an esterification reaction under reduced pressure. (Method 1).

  As the polylactic acid structural unit (E) used in the case of the method 1, polylactic acid composed of lactic acid units constituting the polylactic acid (A) and lactic acid which becomes optical isomerism is used. However, the polylactic acid structural unit (E) is synthesized in the same manner as the polylactic acid (A) except that it is composed of lactic acid having an optical isomerism relationship with the polylactic acid (A).

  The reaction temperature in Method 1 is preferably in the range of 170 to 220 ° C, more preferably in the range of 180 to 210 ° C. By making it react at the temperature of the said range, it is possible to suppress the molecular weight fall of the polylactic acid-type block copolymer (B) obtained, the fall of a hue, and the depolymerization of the said polylactic acid structural unit (E).

  Further, the degree of reduced pressure in the method 1 is preferably higher vacuum because the esterification reaction proceeds more rapidly. Specifically, 267 Pa or less is preferable, 133 Pa or less is more preferable, and 67 Pa or less is particularly preferable.

  Before the polyester structural unit (D ′) is melt-mixed with the polylactic acid structural unit (E), the esterification catalyst used when the polyester structural unit (D ′) is produced in advance is removed or deactivated. It is preferable to make them inactive. Thereby, the molecular weight fall of the polylactic acid-type block copolymer (B) obtained can be suppressed.

  In addition, the polylactic acid structural unit (E) used in the method 1 includes glycolic acid, 2-hydroxy-n-butyric acid, 2-hydroxycaproic acid, 2-hydroxy3, as long as the object of the present invention is not impaired. Copolymers of 3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, 2-hydroxyisocaproic acid, p-hydroxybenzoic acid, various lactones, etc., and mixtures thereof can also be used.

  As the polylactic acid structural unit (E), those having a weight average molecular weight of 10,000 to 400,000 are preferably used, and those having a weight average molecular weight of 30,000 to 400,000 are used. More preferably. By using such a polylactic acid structural unit (E), a polylactic acid block copolymer (B) having a high molecular weight can be produced.

  As said esterification catalyst, the thing similar to what was illustrated as what can be used when manufacturing the said polylactic acid structural unit (E) can be used preferably. The amount of esterification catalyst used is preferably in the range of 50 to 500 ppm, more preferably in the range of 50 to 300 ppm with respect to the total amount of the polyester structural unit (D ′) and the polylactic acid structural unit (E). Is more preferable, and the range of 50 to 200 ppm is particularly preferable. By using the esterification catalyst in such a range, a decrease in the molecular weight of the polylactic acid block copolymer (B) is suppressed, and a polylactic acid block copolymer (B) having a good hue is obtained. Can do.

  Further, the polylactic acid block copolymer (B) is prepared by reducing the polyester structural unit (D ′) and the polylactic acid structural unit (E) under reduced pressure conditions in the presence of a high-boiling solvent using an esterification catalyst. Can also be produced by carrying out an azeotropic dehydration polycondensation reaction with (Method 2).

  As the high boiling point solvent, for example, xylene, anisole, diphenyl ether and the like can be preferably used. Further, the degree of vacuum is preferably in the range of 1000 to 3000 Pa for the purpose of refluxing the high boiling point solvent in the system. In addition, when making it react under reduced pressure, it is preferable to use the apparatus in which the said high boiling point solvent recirculate | refluxs.

  In addition, since moisture causes a decrease in the molecular weight of the polylactic acid block copolymer (B) obtained in general, the polyester structural unit (D ′) and the polylactic acid structural unit (E) are particularly sufficient before the reaction. It is preferable to use a dried one.

  Furthermore, the polylactic acid block copolymer (B) can be produced by reacting the polyester structural unit (D ′) with a lactone in the presence of a ring-opening polymerization catalyst (Method 3).

  The method for producing the polylactic acid block copolymer (B) by reacting the polyester structural unit (D ′) with a lactone in the presence of a ring-opening polymerization catalyst is specifically performed under an inert gas atmosphere. The polyester structural unit (D ′) and the lactide are dissolved, dispersed or homogenized in a suitable good solvent in a reaction kettle set to a temperature, and then reacted by adding a ring-opening polymerization catalyst. Is the method. The reaction temperature is preferably in the range of 150 to 220 ° C., more preferably in the range of 160 to 210 ° C., and in the range of 170 to 200 ° C. from the viewpoint of preventing coloration and thermal decomposition of the polylactic acid block copolymer (B). Particularly preferred.

  Examples of the lactone include lactide. Examples of other lactones include propiolactone, butyrolactone, valerolactone, caprolactone, and a mixture thereof as necessary.

  As the lactide, lactide having an optical isomerism relationship with the lactic acid unit constituting the polylactic acid (A) is used.

  As the polyester structural unit (D ′), it is preferable to use those obtained by sufficiently drying before reaction to remove moisture. This is because moisture present in the system causes an inhibition of the ring-opening polymerization reaction between the polyester and the lactone, a decrease in the molecular weight of the resulting polylactic acid block copolymer (B), and the like.

  As a solvent that can be used in (Method 3), for example, an inert solvent such as toluene is used. The addition amount of the solvent is preferably 3 to 30 parts by mass, more preferably 5 to 30 parts by mass with respect to the total amount of the polyester structural unit (D ′) and the lactone. It is preferable to use 5 to 20 parts by mass.

  As the ring-opening polymerization catalyst, for example, metals such as Sn, Ti, Zr, Zn, Ge, Co, Fe, Al, Mn, and Hf or organometallic compounds can be preferably used. Among these, tin powder, tin octoate, tin 2-ethylhexylate, dibutyltin dilaurate, tetraisopropyl titanate, tetrabutoxy titanium, titanium oxyacetylacetonate, iron (III) acetylacetonate, iron (III) ethoxide, aluminum isopro Poxide and aluminum acetylacetonate are preferable because they are ring-opening polymerization catalysts having a high activity for reaction.

  The amount of the ring-opening polymerization catalyst used is preferably in the range of 50 to 500 ppm, more preferably in the range of 50 to 300 ppm, and more preferably in the range of 50 to 200 ppm with respect to the total amount of the polyester structural unit (D ′) and the lactone. Particularly preferred. As long as the amount of the ring-opening polymerization catalyst used is within such a range, a decrease in the molecular weight of the polylactic acid block copolymer (B) is suppressed and a polylactic acid block copolymer (B) having a good hue is obtained. Can do.

  As the method for producing the polylactic acid block copolymer (B), among the above (Method 1) to (Method 3), it is usually unnecessary to remove a large amount of solvent (Method 1) and (Method). 3) is preferred.

  In addition, the polylactic acid block copolymer (B) is obtained by, for example, producing a polylactic acid block copolymer (B) obtained by the production method as described above, and further adding a polyfunctional polyol, an acid anhydride, or a polyvalent isocyanate. Alternatively, it may be a polymer having a high molecular weight by reaction with an epoxy compound or a peroxide.

  The ring-opening polymerization catalyst and esterification catalyst used in the production of the polylactic acid block copolymer (B) may be extracted and removed by using an appropriate solvent as necessary. The esterification catalyst or the like may be deactivated using.

  Moreover, you may use an adjuvant suitably for the purpose of improving the storage stability of the said polylactic acid-type block copolymer (B). As such an auxiliary agent, for example, carbodiimide can be used.

  Next, the trimesic acid triamide compound (C) used in the present invention will be described. The trimesic acid triamide compound (C) used in the present invention is represented by the following general formula (1).

〔一般式（１）中のＲ^１、Ｒ^２及びＲ^３は、それぞれ独立に、炭化水素基を表す。］

[R ¹ , R ² and R ³ in the general formula (1) each independently represent a hydrocarbon group. ]

  The trimesic acid triamide compound (C) represented by the general formula (1) forms a crystal nucleus of the polylactic acid (A) or the polylactic acid block copolymer (B), and promotes crystallization thereof. It acts effectively as a nucleating agent, and contributes to an improvement in the crystallization speed and crystallinity of the resulting polylactic acid resin composition, that is, an improvement in heat resistance and molding processability. Furthermore, it is also effective in improving the transparency that usually deteriorates as crystallization progresses.

Examples of the hydrocarbon group (R ¹ , R ² and R ³ ) in the general formula (1) include an alkyl group, an alicyclic group, and an aromatic group.

  Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a second butyl group, a third butyl group, an n-amyl group, a third amyl group, and a hexyl group. , Heptyl group, n-octyl group, 2-ethylhexyl group, tertiary octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, octadecenyl Groups and the like.

  Among these alkyl groups, an alkyl group having 3 to 14 carbon atoms is preferable regardless of whether it is linear or branched, and an alkyl group having 4 to 8 carbon atoms is preferable whether it is linear or branched. More preferably, n-pentyl group and n-hexyl group which are linear alkyl groups having 5 or 6 carbon atoms are more preferable.

  Examples of the alicyclic group include unsubstituted or cyclohexyl groups having an alkyl group having 1 to 6 carbon atoms. Examples of such alicyclic groups include cyclohexyl group, 2-methylcyclohexyl group, 3-methylcyclohexyl group, 4-methylcyclohexyl group, 2-ethylcyclohexyl group, 3-ethylcyclohexyl group, 4-ethylcyclohexyl group. 2-n-propylcyclohexyl group, 3-n-propylcyclohexyl group, 4-n-propylcyclohexyl group, 2-iso-propylcyclohexyl group, 3-iso-propylcyclohexyl group, 4-iso-propylcyclohexyl group, 2 -N-butylcyclohexyl group, 3-n-butylcyclohexyl group, 4-n-butylcyclohexyl group, 2-iso-butylcyclohexyl group, 3-iso-butylcyclohexyl group, 4-iso-butylcyclohexyl group, 2-sec -Butylcyclo Xyl group, 3-sec-butylcyclohexyl group, 4-sec-butylcyclohexyl group, 2-tert-butylcyclohexyl group, 3-tert-butylcyclohexyl group, 4-tert-butylcyclohexyl group, 2,3-dimethylcyclohexyl group 2,4-dimethylcyclohexyl group, 2,5-dimethylcyclohexyl group, 2,6-dimethylcyclohexyl group, 2,3,4-trimethylcyclohexyl group, 2,3,5-trimethylcyclohexyl group, 2,3,6 -Trimethylcyclohexyl group, 2,4,6-trimethylcyclohexyl group, 3,4,5-trimethylcyclohexyl group and the like can be mentioned.

  Examples of alicyclic groups other than the above include, for example, cyclopropyl group, cyclobutyl group, cyclopentyl group, cycloheptyl group, cyclooctyl group, cyclododecyl group, cyclohexylmethyl group, methylcyclohexylmethyl group, dimethylcyclohexylmethyl group, trimethylcyclohexyl. Methyl group, methoxycyclohexylmethyl group, ethoxycyclohexylmethyl group, dimethoxycyclohexylmethyl group, chlorocyclohexylmethyl group, dichlorocyclohexylmethyl group, α-cyclohexylethyl group, β-cyclohexylethyl group, methoxycyclohexylethyl group, dimethoxycyclohexylethyl group, Chlorocyclohexylethyl group, dichlorocyclohexylethyl group, α-cyclohexylpropyl group, β-cyclohexylpropyl group, γ- Examples thereof include a cyclohexylpropyl group and a methylcyclohexylpropyl group.

  Examples of the aromatic group include a phenyl group, an alkyl-substituted phenyl group, a 1-naphthyl group, a 2-naphthyl group, a 1-aminoanthracene group, a 2-aminoanthracene group, an ethylphenyl group, a propylphenyl group, a benzyl group, Methylbenzyl group, dimethylbenzyl group, trimethylbenzyl group, methoxybenzyl group, ethoxybenzyl group, dimethoxybenzyl group, chlorobenzyl group, dichlorobenzyl group, α-phenylethyl group, β-phenylethyl group, methoxyphenylethyl group, dimethoxy Examples include phenylethyl group, chlorophenylethyl group, dichlorophenylethyl group, α-phenylpropyl group, β-phenylpropyl group, γ-phenylpropyl group, methylphenylpropyl group and the like.

  Of the above hydrocarbon groups, a cyclohexyl group is most preferred.

  The trimesic acid triamide compound (C) can be obtained by amidating trimesic acid or an acid chloride thereof with an amine substituted with a corresponding hydrocarbon.

  These trimesic acid triamide compounds (C) can be used alone or in combination of two or more.

  The shape of the trimesic acid triamide compound (C) in the polylactic acid resin composition of the present invention is not particularly limited, but at the time of melt-kneading the polylactic acid (A) and the polylactic acid block copolymer (B) As a result of improving the nucleating action and transparency of the polylactic acid resin composition, the crystallinity of the resulting molded body is increased and the heat resistance is improved, so that the average particle size is The powder is preferably in the range of 0.01 to 30 μm.

  Next, the polylactic acid resin composition of the present invention will be described. In the polylactic acid resin composition of the present invention, the crystallization speed and crystallinity of polylactic acid are increased, and since it has bleed resistance, it is excellent in heat resistance, flexibility, impact resistance, molding processability, and Transparency is maintained by the effect that seems to be caused by reducing the size of the crystals of polylactic acid produced or controlling the proportion of crystals produced, while transparency usually deteriorates as crystallization progresses. The

  In the polylactic acid resin composition of the present invention, the mass ratio (A) / (B) of the polylactic acid (A) and the polylactic acid block copolymer (B) is in the range of 95/5 to 30/70. It is preferable that the range is 90/10 to 40/60 because the effect of further promoting crystallization is high and the heat resistance, rigidity, bleed resistance and molding processability are excellent.

  More specifically, the polylactic acid resin composition of the present invention has a mass ratio (A) / (B) of 95/5 between the polylactic acid (A) and the polylactic acid block copolymer (B). The range of -30/70 is preferable, and the range of 90 / 10-40 / 60 is more preferable. The polylactic acid resin composition preferably has a mass ratio (A) / (B) of 95/5 to 30/70 of the polylactic acid (A) and the polylactic acid block copolymer (B), The range of 85/15 to 40/60 is more preferable.

  In the polylactic acid resin composition of the present invention, 0.05 to 5 mass of the trimesic acid triamide compound (C) is added to the total amount of the polylactic acid (A) and the polylactic acid block copolymer (B). The trimesic acid triamide compound (C) is preferably uniformly dissolved in the polylactic acid (A) and the polylactic acid-based block copolymer (B), thereby more effective crystal nucleus growth. In order to make it contain, it is more preferable to contain in the range used as 0.10-1 mass part.

  Here, the following considerations hold as theoretical knowledge about the amount of the trimesic acid triamide compound (C) added. That is, when the trimesic acid triamide compound in the polylactic acid resin composition works completely as a crystal nucleating agent, one nucleus exists at the center of all spherulites. Therefore, if the nucleating agent particles are increased in the polylactic acid resin composition, the spherulite size should be reduced. Specifically, for example, if there is a spherulite having a diameter of 100 nm around a nucleating agent particle having a diameter of 10 nm, the mixing (volume) ratio of the crystal nucleating agent is 1/1000 = 0.1%. If the diameter of the spherulite is 50 nm, the volume ratio is 1/125 = 0.8%.

  On the other hand, using the polylactic acid resin composition of the present invention, for example, in order to make the obtained sheet transparent, considering that the crystal nucleating agent does not work completely or its specific gravity, the spherulite is made transparent. The spherulite size may be smaller than the Rayleigh scattering. Specifically, the size of the spherulite at this time is about 100 nm in diameter, and the mixing (volume) of the crystal nucleating agent The ratio may be appropriately adjusted within a range of 0.05 to 0.2%.

  The polylactic acid resin composition of the present invention is prepared by mixing (1) polylactic acid (A), polylactic acid block copolymer (B), and trimesic acid triamide compound (C) with an appropriate mixer, and sufficient kneading ability (2) After the polylactic acid (A) and the polylactic acid block copolymer (B) are heat-melted and kneaded, the trimesic acid triamide compound (C) And, if necessary, supplying other additives, uniformly mixing using a high-speed stirrer or low-speed stirrer, and then heat-melt-kneading with a single-screw or multi-screw extruder having sufficient kneading ability, (3 ) A so-called master bag in which a small amount of polylactic acid (A), an excess of polylactic acid block copolymer (B) and an excess of trimesic acid triamide compound (C) were previously mixed and melt-kneaded. When the polylactic acid (A), can be prepared by methods such as heating and melting and kneading using an extruder. Moreover, it is preferable that the shape of the said masterbatch is a pellet, powder, etc.

  By kneading the components, the polylactic acid resin composition of the present invention can be obtained. However, the kneading method of the components is not particularly limited, and can be mixed by various methods. For example, a dry blend method in which each component is charged and kneaded in a tumbler, V-type blender, ribbon blender, Hellshell mixer, tumbler mixer, etc., and the dry blend is melt-kneaded with a single or twin screw extruder, kneader, roll, etc. And then cooling and pelletizing, or a solution blending method in which each resin is dissolved in a solvent and mixed to remove the solvent.

  As a more specific method for producing the polylactic acid resin composition of the present invention, a tritrimesic acid triamide compound (in addition to the above-mentioned three production methods, polylactic acid (A) and a polylactic acid block copolymer (B) ( Examples thereof include a method of melt-kneading until the tritrimesic acid triamide compound (C) is uniformly dispersed at a temperature equal to or higher than a temperature at which C) dissolves (hereinafter, dissolution temperature). Thereby, since it has an excellent crystallization speed, a high degree of crystallinity can be imparted to the molded body in a short time, and a molded body having excellent heat resistance, impact resistance, and molding processability can be obtained.

  The trimesic acid triamide compound represented by the general formula (1) used as the tritrimesic acid triamide compound (C) in the present invention generally has a melting point in the range of 180 to 400 ° C. When the lactic acid block copolymer (B) and the trimesic acid triamide compound are melt-kneaded, the polylactic acid (A) and the polylactic acid block copolymer (B) are first melted, and then the trimesic acid triamide compound is converted into poly Dissolves in lactic acid (A) and polylactic acid block copolymer (B). Here, the dissolution temperature is preferably in the range of 190 to 260 ° C., more preferably in the range of 200 to 255 ° C., suppressing thermal decomposition of the polylactic acid (A) and the polylactic acid block copolymer (B), and trimesic acid It is particularly preferable to dissolve the triamide compound in the range of 210 to 250 ° C. because the triamide compound is more uniformly dispersed.

  In the polylactic acid resin composition of the present invention, after melting at the melting temperature, the trimesic acid triamide compound dissolved once is precipitated by cooling and solidifying immediately, and the precipitated trimesic acid triamide compound forms fine nuclei. Increase the property, crystallization speed and crystallinity.

  As a method for easily measuring the dissolution temperature in advance, for example, using an optical microscope attached with a temperature controller such as a heating plate, while heating the polylactic acid resin composition, The temperature until the solid derived from the trimesic acid triamide compound present in the polylactic acid block copolymer (B) is no longer observed is observed. Further, the melt kneading until the trimesic acid triamide compound is actually not observed can be carried out by adjusting the residence time of the polylactic acid resin composition at the time of heating and melting, the rotational speed of the screw, and the like. Next, the polylactic acid resin composition is cooled and crystallized by being subjected to a molding process while maintaining this molten state. The temperature during cooling (for example, the mold temperature in injection molding) is preferably in the range of the glass transition temperature of the polylactic acid resin composition to 140 ° C, particularly in the range of 80 to 120 ° C. By using such a molding method, it is possible to obtain a molded body having a high crystallization speed, a high crystallinity and bleed resistance, and excellent heat resistance, impact resistance, flexibility and molding processability. .

  As the polylactic acid resin composition of the present invention, for example, using a differential scanning calorimeter “DSC 220C” manufactured by Seiko Denshi Kogyo Co., Ltd., 10 mg of the polylactic acid resin composition is put in a measurement container, and a nitrogen gas flow rate of 50 mL is used. The crystallization peak temperature observed when the temperature is raised from 20 ° C. to 210 ° C. at a heating rate of 10 ° C./min is observed in the range of 110 ° C. to the melting point of the polylactic acid resin composition. From the viewpoint of excellent heat resistance, it is more preferable that the crystallization peak temperature is observed in the range of 115 to 160 ° C. because of excellent heat resistance.

In addition, the polylactic acid resin composition of the present invention uses DSC to put 10 mg of the polylactic acid resin composition into a measurement container, and from 20 ° C. to 210 ° C. at a nitrogen gas flow rate of 50 mL / min and a heating rate of 10 ° C./min. The temperature is raised and then held at 210 ° C. for 3 minutes, then the temperature is lowered to −100 ° C. at a cooling rate of 20 ° C./min, and the second temperature rise is again carried out to 200 ° C. At this time, using the melting calorie peak area (ΔHm) of the DSC curve drawn at the time of secondary heating and the crystallization calorie peak area (ΔHc) of the DSC curve drawn at the time of primary heating, it is calculated from the following formula: The crystallinity α is preferably in the range of 20 to 100%, more preferably in the range of 30 to 100% in order to have an excellent crystallization rate, and 40 in order to have remarkable moldability. It is particularly preferred to have a range of ~ 100%.
Crystallinity α = [(ΔHm−ΔHc) / ΔHm] × 100 (%)

  The polylactic acid resin composition of the present invention can be used in combination with other resins as required. For example, a general-purpose resin represented by polyethylene, polypropylene, polyethylene, polystyrene, polycaprolactone, polybutylene succinate, Biodegradable resins typified by cellulose acetate, polyethylene oxide, methacrylbutylene styrene resin (MBS resin), acrylonitrile butylene styrene resin (ABS resin), etc. can be used, especially from the viewpoint of reducing environmental impact It is preferable to use a thermoplastic resin.

  The polylactic acid resin composition according to the present invention includes a pigment, a lubricant, an antioxidant, a heat stabilizer, an ultraviolet absorber, a hindered amine light stabilizer, and an antistatic agent within the range that does not impair the present invention. Agents, flame retardants, tackifiers, plasticizers, fillers, internal mold release agents, antibacterial and antifungal agents, and other fillers can be added.

  The pigment is roughly classified into an organic pigment and an inorganic pigment, and as an inorganic pigment, as an extender, precipitated barium sulfate, precipitated calcium carbonate, white carbon (silica), calcined clay, kaolin clay, talc, etc. Titanium oxide, zinc white, titanium black, yellow iron oxide, dial, black iron, chromium oxide, viridian etc. as metal oxide, cobalt blue, cobalt green, titanium yellow etc. as complex metal oxide, yellow as chromate Lead, chromium vermilion, etc., sulfides such as lithopone, cadmium yellow, cadmium red, etc., phosphates such as cobalt violet deep, metal complexes such as bitumen, ultramarine blue, carbon as carbon black, etc. as metal powder Aluminum powder, zinc powder, etc., cobalt violet nova There are exemplified, respectively. Organic pigments can be broadly classified into azo pigments and condensed polycyclic pigments, but azo pigments are insoluble azo pigments (noazo yellow, disazo yellow, β-naphthol, naphthol AS, pyrazolone, benzimidazolone) ), Condensed azo pigments (yellow, red), azo lake pigments (yellow, β-naphthol type, BON acid type, naphthol AS type), etc., as condensed polycyclic pigments, phthalocyanine type pigments (blue, green), quinacridone type Pigments, anthraquinone pigments (indanthrone blue, anthraquinone), perylene pigments, perylene pigments, indigo pigments, dioxazine pigments, quinophthalone pigments, isoindolinone pigments, diketopyrrolopyrrole pigments, etc. It is done. The amount of these pigments can be used within a range of 0.05 to 1 part by mass with respect to 100 parts by mass of the resin content.

  Antioxidants include 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, distearyl 3,3′-thiodipropio Nate, dilauryl 3,3′-thiodipropionate, etc., heat stabilizers such as triphenyl phosphite, trilauryl phosphite, trisnonyl phenyl phosphite, etc., and UV absorbers such as p-t-butyl Phenyl salicylate, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-2'-carboxybenzophenone, 2,4,5-trihydroxybutyrophenone and the like are N, N-bis ( Hydroxyethyl) alkylamine, alkylamine, alkylallylsulfonate, a Such as Kill sulfonate, and the like. The amount of these additives can be used within a range of 0.01 to 5 parts by mass with respect to 100 parts by mass of the resin.

  Various flame retardants can be used as the flame retardant, for example, halogen-based flame retardants such as bromine and chlorine, antimony flame retardants such as antimony trioxide and antimony pentoxide, aluminum hydroxide and hydroxide. Inorganic flame retardants such as magnesium and silicone compounds, phosphorus flame retardants such as red phosphorus, phosphate esters, ammonium polyphosphate and phosphazene, melamine, eye ram, melem, melon, melamine cyanurate, melamine phosphate, pyroline Melamine acid melamine, melamine polyphosphate, melam, melem double salt, melamine alkylphosphonate, melamine phosphonate, melamine sulfate, melamine methanesulfonate, and fluororesin such as PTFE. The amount of these flame retardants can be used within a range of 0.05 to 100 parts by mass with respect to 100 parts by mass of the resin content.

  Various lubricants can be used as the lubricant, such as N, N′-dicyclohexyl-2.6-naphthalenedicarboxyamide, N, N, N ′, N′-tetracyclohexyl-1,4-butane. Tetraamide, N, N ′, N ″ -tricyclohexyltrimesic amide, N, N′-diphenyl-3-sulfonyldibenzamide, N, N ′, N ″ -tributyltrimesic amide, N, N′— Diphenylterephthalamide, N, N′-diphenylsuccinamide, N, N′-diphenylsubericamide, sodium salt of bis (3,5-di-t-butyl-2-phosphophenyl) methane, di-t- Butyl aluminum benzoate, aliphatic carboxylic acid, aliphatic carboxylic acid amide, palmitic acid amide, stearic acid Amide, erucic acid amide, behenic acid amide, ricinoleic acid amide, hydroxy stearic acid amide, N-oleyl palmitic acid amide, N-stearyl erucic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, ethylene biserucic acid amide , Ethylene bisoleic acid amide, m-xylylene bis stearic acid amide, m-xylylene bis-12-hydroxystearic acid amide, sodium stearate, potassium stearate, zinc stearate, calcium montanate, aliphatic as aliphatic carboxylate Examples of the carboxylic acid ester include ethylene glycol distearate, and examples of the aliphatic alcohol include stearyl alcohol. The amount of these lubricants can be used within a range of 0.05 to 100 parts by mass with respect to 100 parts by mass of the resin content.

  As the filler, various inorganic fillers can be used. For example, talc, silica, mica, kaolin, clay, calcium carbonate, magnesium sulfate, titanium oxide, glass beads, glass flakes, glass fiber, carbon fiber, silicon dioxide Boron nitride, tin oxide, molybdenum oxide, magnesium oxide, iron oxide, aluminum oxide, germanium oxide, calcium carbonate, barium sulfate and the like. The amount of these inorganic fillers can be used within a range of 0.05 to 50 parts by mass with respect to 100 parts by mass of the resin content.

  Other fillers include kenaf fiber. The kenaf fiber applied to the present invention preferably has an average fiber length of 100 μm to 20 mm and includes a kenaf fiber having a fiber length of at least 300 μm to 20 mm. When the polylactic acid resin composition of the present invention contains kenaf fibers having such a range, the reinforcing effect of the molded body is further enhanced. More preferably, the average fiber length of the kenaf fiber is 1 to 10 mm, and the reinforcing effect of the polylactic acid resin composition can be further improved. Here, the average fiber length means the number average fiber length of the fibers excluding the crushed pieces, and the crushed pieces are defined as those having a length in the longitudinal direction of less than 50 μm.

  When the contained kenaf fiber has an average fiber length of more than 20 mm or contains kenaf fiber having a fiber length of more than 20 mm, the resin is produced in a production apparatus such as a kneader when producing a kenaf fiber-reinforced resin composition. Dispersion of fibers in the inside tends to be uneven. If fibers that are too long with respect to the thickness of the molded product are included, the appearance and feel of the molded product are impaired, so the maximum fiber length is preferably 10 times or less, more preferably 5 times the thickness of the molded product. Is less than double. Further, at the time of injection molding, the resin composition becomes clogged in the molding apparatus. In particular, kenaf fibers having a fiber length exceeding 50 mm are desirably removed before being introduced into the kneader. On the other hand, when a kenaf fiber reinforced resin composition containing only kenaf fibers having a fiber length of less than 300 μm is used, the reinforcing effect of the kenaf fibers is not sufficient.

  When the polylactic acid resin composition of the present invention contains a kenaf fiber having an average fiber length of 100 μm to 20 mm and including a kenaf fiber having a fiber length of at least 300 μm to 20 mm, not only the strength is improved but also thermal deformation. The effect of improving heat resistance with temperature as an index can also be expected.

  Examples of the internal release agent used in the present invention include release agents such as ordinary higher fatty acids and salts thereof, ester oils, silicone oil, polyvinyl alcohol, polyalkyl glycol, low molecular weight polyolefin, etc. Is preferred. Specific examples of silicone oils include, for example, straight silicone oils such as dimethyl silicone oil, methyl hydrogen silicone oil, methylphenyl silicone oil, and cyclic dimethyl silicone oil, polyether-modified silicone oil, methylstyryl-modified silicone oil, and alkyl-modified silicone. Examples include oils, higher fatty acid ester-modified silicone oils, hydrophilic specially modified silicone oils, and modified silicone oils such as higher fatty acid-containing silicone oils. In terms of safety, dimethyl silicone oil, methylphenyl silicone oil, cyclic dimethyl silicone Oil is preferred. The amount of these internal mold release agents can be used within a range of 0.05 to 10 parts by mass with respect to 100 parts by mass of the resin content.

  The polylactic acid resin composition of the present invention can be molded to obtain a polylactic acid resin molded article.

  Since the polylactic acid resin composition of the present invention is excellent in molding processability, various molded products can be obtained. The production method of various molded products is not particularly limited, and various methods such as extrusion molding, injection molding, calender molding, vacuum molding, pressure molding, match molding, new generation forming, etc., similar to general plastics. Depending on the molding method, it can be easily molded into molded products of various shapes, and the resulting molded product can have high strength and excellent thermal stability. It can also be formed into a fiber by melt spinning.

  As a molded product that can be produced using the polylactic acid resin composition of the present invention, it can be used for molded products such as films, fibers, various containers, various parts, etc., and is particularly suitable for the production of films and sheets. Material. Specific methods for forming a film or sheet include an extrusion method, a co-extrusion method, a calendar method, a hot press method, a solvent casting method, an inflation method, a balloon method, a tenter method, etc., but there are no limitations on the method. Absent.

  In addition, the film said by this invention is not restrict | limited at all in terms of the shape, a magnitude | size, thickness, a design, etc. In the present invention, in order to avoid confusion, the expression of the film and the sheet is unified to “film”. The film of the present invention preferably has a thickness in the range of 5 μm to 2 mm.

  When the film is formed by the extrusion method, for example, a die such as a T die, an inflation die (circular die), a flat die, or a single manifold die can be used. According to the co-extrusion method, a multilayer film can be produced using a plurality of the polymers and / or other kinds of polymers having different properties.

  A film made of the polylactic acid resin composition of the present invention is formed by the above-described various forming methods, and a film in a heat-melted state is usually cast so as to have a predetermined thickness, and is cooled and solidified as necessary. In that case, a uniform film can be produced by properly using a touch roll, an air knife, and, if thin, electrostatic pinning.

  The film can be uniaxially and biaxially stretched at a temperature not lower than the glass transition temperature (Tg) of the polylactic acid resin composition and not higher than the melting point by a known and common method such as a tenter method or an inflation method. The stretching temperature is preferably in the range of Tg to (Tg + 50) ° C. of the polylactic acid resin composition, and particularly preferably in the range of Tg to (Tg + 30) ° C.

  In the case of uniaxial stretching, it is preferable to stretch 1.3 to 10 times in the longitudinal direction or the transverse direction by longitudinal stretching by a roll method or transverse stretching by a tenter. In the case of biaxial stretching, it is preferably performed by longitudinal stretching by a roll method and transverse stretching by a tenter. The stretching may be performed sequentially or simultaneously with the first and second axes. The draw ratio is preferably 1 to 3 times in the longitudinal direction and the transverse direction.

  By molding the obtained stretched film, a molded body having particularly excellent transparency, heat resistance, impact resistance, and molding processability can be obtained. The expression of the performance described above is obtained because the film is oriented and crystallized by stretching. In particular, in the case of the film, the performance is achieved by the synergistic effect of the crystal nucleating agent of the trimesic acid triamide compound and the oriented crystal of the polylactic acid resin composition. The level can be dramatically improved.

  In addition, the film may be subjected to a heat setting process in a state in which the film is stretched within a range that does not impair a haze value described later immediately after stretching, thereby removing distortion of the film (suppression of shrinkage) or promoting crystallization. it can. The heat setting treatment temperature can be in the range of the glass transition temperature (Tg) of the polylactic acid resin composition to the melting point of the polylactic acid resin composition, but is preferably in the range of 50% to 160 ° C, more preferably 60% to 140. When carried out in the range of ° C., not only the heat resistance but also other film physical properties such as tensile elongation and tensile strength can be improved. However, if the film is completely crystallized by heat treatment after stretching, it becomes difficult to perform heat processing and it becomes difficult to obtain a good molded product.

  The heat setting treatment time is usually in the range of 0.1 second to 30 minutes, but when practicality such as productivity is considered, this time is preferably as short as possible, and is preferably in the range of 0.1 second to 3 minutes. More preferably, it is the range of 0.1 second-1 minute.

  The film preferably has a haze value in the range of 0.1 to 50%. If finer crystal nuclei can be realized, the haze value is in the range of 0.1 to 40%. In particular, when transparency is applied to a field where transparency is required, the haze value of the film is preferably in the range of 0.1 to 10%.

  As a method for measuring the haze value, the polylactic acid resin composition was vacuum-dried at 80 ° C. for 3 hours, and then heated and melted at 200 ° C. using a heating press, so that the length was 15 cm, width 15 cm, and thickness 200 μm. A film was prepared. This film was cut into a 5 cm × 5 cm square, and the haze value on the film surface was measured according to JIS K 7105 using a turbidimeter (“ND-1001DP” manufactured by Nippon Denshoku Industries Co., Ltd.).

  The film obtained by the above method can be further subjected to secondary processing by a method such as blow processing, vacuum forming, and pressure forming. Specifically, by secondary processing of the film, for example, a take-out bag for a supermarket, a bag for preventing water condensed on a low temperature food pack such as frozen food or meat, a compost bag, etc. Bags and bags can be manufactured. In the secondary processing, it is particularly preferable to perform a heat treatment in the range of a glass transition temperature to 150 ° C. in order to improve the heat resistance of the film before and after forming.

  The film of the present invention is a shrink film, vapor deposition film, wrap film, food packaging, other general packaging, garbage bags, plastic bags, general standard bags, heavy bags, hygiene materials such as paper diapers and sanitary products, wounds, etc. Medical materials such as covering materials, agricultural materials such as germination films, agricultural multi-films, curing films and seedling pots, surface lamination materials for paper products such as trays, cups, dishes and megaphones, and other binding tapes (binding) Band), prepaid cards, balloons, cellophane adhesive tape, umbrellas, goose, gloves, cigarette filters, etc.

  The polylactic acid resin composition of the present invention is, for example, a film having a length of 15 cm, a width of 15 cm, and a thickness of 200 μm, which is vacuum-dried at 80 ° C. for 3 hours, and then heated and melted at 190 ° C. using a heating press and cooled and solidified. Can be produced. When the MIT bending strength test is performed using the film according to JIS-P-8115, it is preferably 3,000 times or more, more preferably 5,000 times or more, and particularly preferably 10,000 times. By having the above-mentioned number of times, it becomes a judgment material for impact resistance such as cracking and brittleness of a molded product. Here, in PET (A-PET) which is one of general-purpose resins, it is 3,000 times or more in the MIT bending strength test. Therefore, it is practically preferable that it is 3,000 times or more according to the MIT bending strength test.

The film obtained from the polylactic acid resin composition of the present invention has excellent heat resistance by heat treatment. As a method for measuring the heat resistance of the film, for example, a test piece having a width of 20 mm, a length of 120 mm, and a thickness of 250 μm is formed using a flange portion of a molded body obtained by vacuum forming the film (both ends in the longitudinal direction of the test piece). And a jig with a container containing a weight of about 160 g in total weight attached to the clip is attached to one end of the test piece (clip holding part 10 mm), The other end is fixed with an appropriate jig so that the film and the weight hang down. This was left still in a thermostatic gear oven set to 100 ° C. (for example, GPHH-101 manufactured by Espec Corp.) so that the test piece was positioned at the center of the thermostat and heated for 1 minute. After taking out and cooling the test piece from the thermostat, the length (A: unit mm) of the sample piece is measured, and heating and load loading treatment (in a 100 ° C. environment, a 0.4 MPa load for 1 minute) The length change rate D (unit%) with respect to the length before processing after load) was calculated by the following equation. For example, if D is 0%, it can be determined that the sample piece has a heat resistance of 100 ° C. substantially.
Length change rate D = [(A-100) / 100] × 100 (%)

  The length change rate D at 100 ° C. in the heat resistance test method is preferably in the range of 0 to 30%, more preferably 0 to 10%, and particularly preferably 0 to 5% in order to have excellent heat resistance. .

  The film or container obtained by molding the polylactic acid resin composition of the present invention has excellent bleed resistance. For example, when a film having a thickness of 100 to 600 μm obtained by molding the polylactic acid resin composition of the present invention is cut into a 10 cm × 10 cm square and left in a constant temperature and humidity chamber with a humidity of 90% at 40 ° C., Generation of bleeding from the film surface is not observed for at least 200 days.

  The present invention will be specifically described below with reference to examples and comparative examples.

[Method for measuring number average molecular weight (Mn) and weight average molecular weight (Mw)]
Using a gel permeation chromatography measuring device (“HLC-8220” manufactured by Tosoh Corporation), two TSK gel SuperHZM-M, two TSK gel SuperHZ-2000, and TSK SuperH as guard columns are used as columns. -H was used, tetrahydrofuran was used as a developing solvent, and the molecular weights of polylactic acid and polylactic acid block copolymer were measured by comparison with standard polystyrene.

[Measurement method of glass transition temperature (Tg)]
Using a differential scanning calorimeter (“DSC 220C” manufactured by Seiko Denshi Kogyo Co., Ltd.) and a nitrogen gas flow rate of 50 mL / min and a heating rate of 10 ° C./min, 10 mg of a polylactic acid block copolymer is put in a measurement container. The temperature was raised from 20 ° C. to 210 ° C., held at 210 ° C. for 3 minutes, then cooled down to −100 ° C. at a cooling rate of 50 ° C./min, and again the secondary temperature rise to 200 ° C. The glass transition temperature and melting point were determined from the DSC curve.

[Mole composition ratio of the diol structural unit constituting the polyester, the dicarboxylic acid structural unit and the hydroxycarboxylic acid structural unit, and the weight composition ratio of the polyhydroxycarboxylic acid structural unit and the polyester structural unit constituting the polylactic acid block copolymer] Measuring method〕
^{By using a 1} H-NMR apparatus (“JNM-LA300” manufactured by JEOL Ltd.) and analyzing a chloroform-d (CDCl ₃ ) solution of the polyester, a diol structural unit in the polyester, dicarboxylic acid The molar composition ratio (mol%) of the structural unit and the hydroxycarboxylic acid structural unit was measured.

Further, by analyzing a chloroform-d (CDCl ₃ ) solution of the polylactic acid block copolymer using the same apparatus as described above, the polyhydroxycarboxylic acid structural unit and the polyester structural unit constituting the block copolymer are analyzed. The weight composition ratio (mass%) was calculated.

Production Example 1 [Production of polyester (D′-1)]
A reactor was charged with 1000 g of succinic acid (hereinafter abbreviated as “SuA”) and 696 g of propylene glycol (hereinafter abbreviated as “PG”), and the temperature was raised from 150 ° C. to 20 ° C. per hour in a nitrogen stream. Then, the esterification reaction was performed by heating and stirring to 220 ° C. while distilling off the generated water. One hour after reaching 220 ° C., 70 ppm of titanium tetrabutoxide as a polymerization catalyst was added to the total charged amount of SuA and PG, and the pressure was reduced to 3,500 Pa, followed by stirring with heating. Further, after 1 hour under reduced pressure, the pressure was reduced to 100 Pa and reacted for 7 hours. After completion of the reaction, 80 ppm of 2-ethylhexanoic acid phosphate was added to the obtained polyester as a deactivator for the polymerization catalyst, whereby a polyester having a number average molecular weight of 15,000 and a weight average molecular weight of 24,000 (D ′ -1) was obtained. The acid value of the polyester (D′-1) is 0.5, the glass transition temperature is −4 ° C., and the composition ratio of the structural unit derived from PG and the structural unit derived from SuA is 50.4 / 49.6 (mol). %)Met.

Production Example 2 [Production of Polyester (D′-2)]
The reactor was charged with 1024 g of SuA, 586 g of PG and 600 g of 90% by weight lactic acid aqueous solution, heated from 150 ° C. to 20 ° C. per hour in a nitrogen stream, and heated and stirred to 220 ° C. while distilling off the generated water, thereby esterifying. Reaction was performed. One hour after reaching 220 ° C., titanium tetrabutoxide as a polymerization catalyst was added in an amount of 70 ppm with respect to the total amount of charged SuA, PG and lactic acid (solid content), and the pressure was reduced to 3,000 Pa, followed by stirring with heating. Further, after 1 hour under reduced pressure, the pressure was reduced to 100 Pa and reacted for 5 hours. After completion of the reaction, 80 ppm of 2-ethylhexanoic acid phosphate was added to the obtained polyester as a deactivator for the polymerization catalyst, whereby a polyester having a number average molecular weight of 17,000 and a weight average molecular weight of 25,000 (D ′ -2) was obtained. The acid value of the polyester (D′-2) is 0.8, the glass transition temperature is 5 ° C., and the composition ratio of the structural unit derived from PG, the structural unit derived from SuA, and the structural unit derived from LA is 31.2 / It was 36.3 / 32.5 (mol%).

Production Example 3 [Production of Polyester (D′-3)]
A reactor was charged with 1000 g of sebacic acid (hereinafter abbreviated as “SeA”) and 414 g of PG, and the temperature was increased from 150 ° C. to 20 ° C. per hour under a nitrogen stream, and the generated water was distilled off to 230 ° C. The esterification reaction was carried out with heating and stirring. One hour after reaching 230 ° C., 70 ppm of titanium tetrabutoxide was added as a polymerization catalyst to the total amount of SeA and PG charged, and the pressure was reduced to 3,500 Pa, followed by stirring with heating. Further, after 2 hours under reduced pressure, the pressure was reduced to 100 Pa and reacted for 7 hours. After completion of the reaction, 80 ppm of 2-ethylhexanoic acid phosphate was added to the obtained polyester as a deactivator for the polymerization catalyst, whereby a polyester having a number average molecular weight of 43,000 and a weight average molecular weight of 60,000 (D ′ -3) was obtained. The acid value of the polyester (D′-3) is 0.2, the glass transition temperature is −48 ° C., and the composition ratio of the structural unit derived from PG and the structural unit derived from SeA is 50.8 / 49.2 (mol). %)Met.

Production Example 4 [Production of Polylactic Acid Block Copolymer (B-1)]
In a reaction vessel equipped with a stirrer, 110 g of D-lactide (manufactured by Pulac) and 100 g of polyester (D′-1) of Production Example 1 were uniformly dissolved at 180 ° C. in a nitrogen atmosphere, and then octylic acid. After 42 mg of tin was added, the polymerization reaction was carried out for 3 hours. After completion of the polymerization reaction, 350 ppm of 2-ethylhexanoic acid phosphate, which is a deactivator for the polymerization catalyst, was added to the obtained reaction product, and the number average molecular weight was 26,000, the weight average molecular weight was 37,000, and the glass transition. A block copolymer (B-1) of polylactic acid and polyester having a temperature of 17.3 ° C. was obtained.

Production Example 5 [Production of polylactic acid block copolymer (B-2)]
After 110 g of D-lactide (manufactured by Pulac) and 100 g of the polyester (D′-2) obtained in Production Example 2 are uniformly dissolved at 180 ° C. under a nitrogen atmosphere in a reaction vessel equipped with a stirrer. Then, 42 mg of tin octylate was added, followed by polymerization reaction for 3 hours. After completion of the polymerization reaction, 350 ppm of 2-ethylhexanoic acid phosphate, which is a deactivator for the polymerization catalyst, was added to the obtained reaction product, the number average molecular weight was 27,000, the weight average molecular weight was 38,000, and the glass transition A block copolymer (B-2) of polylactic acid and polyester having a temperature of 24.6 ° C. was obtained.

Production Example 6 [Production of polylactic acid block copolymer (B-3)]
A reactor heated to 210 ° C. was charged with 500 g of the polyester (D′-1) obtained in Production Example 1, and sufficiently heated and melted. Subsequently, 550 g of D-polylactic acid (number average molecular weight: 90,000, weight average molecular weight: 164,000) was added and uniformly heated and melt mixed, and titanium tetrabutoxide as a polymerization catalyst was added to the molten mixture. 150 ppm was added, and the reaction was carried out for 4.5 hours under the conditions of a temperature of 200 ° C. and a reduced pressure of 150 Pa. After completion of the reaction, 500 ppm is added to the reaction product obtained by obtaining 2-ethylhexanoic acid phosphate, which is a deactivator of the polymerization catalyst, the number average molecular weight is 28,000, the weight average molecular weight is 41,000, the glass transition temperature. A polylactic acid block copolymer (B-3) at 13.0 ° C. was obtained.

Production Example 7 [Production of polylactic acid block copolymer (B-4)]
A reactor heated to 210 ° C. was charged with 500 g of the polyester (D′-2) obtained in Production Example 2, and sufficiently heated and melted. Subsequently, 550 g of D-polylactic acid (number average molecular weight: 90,000, weight average molecular weight: 164,000) was added and uniformly heated and melt mixed, and titanium tetrabutoxide as a polymerization catalyst was added to the molten mixture. 150 ppm was added, and the reaction was carried out for 4.5 hours under the conditions of a temperature of 200 ° C. and a reduced pressure of 150 Pa. After completion of the reaction, 500 ppm is added to the reaction product obtained 2-ethylhexanoic acid phosphate, which is a deactivator for the polymerization catalyst, the number average molecular weight is 28,500, the weight average molecular weight is 42,000, the glass transition temperature. A polylactic acid block copolymer (B-4) at 23.8 ° C. was obtained.

Production Example 8 [Production of polylactic acid block copolymer (B-5)]
A reactor heated to 210 ° C. was charged with 500 g of the polyester (D′-1) obtained in Production Example 1, and sufficiently heated and melted. Next, L-polylactic acid (“Lacia H-400” manufactured by Mitsui Chemicals, Inc .: number average molecular weight 92,000, weight average molecular weight 170,000, L isomer: D isomer = 98.5: 1.5 (mol) Ratio); hereinafter abbreviated as “L-PLA”), and 150 ppm of titanium tetrabutoxide as a polymerization catalyst is added to the molten mixture, and the mixture is uniformly heated and melt-mixed. The reaction was carried out for 4.5 hours under the condition of 150 Pa in vacuum. After completion of the reaction, 500 ppm is added to the reaction product obtained by obtaining 2-ethylhexanoic acid phosphate, which is a deactivator of the polymerization catalyst, the number average molecular weight is 28,000, the weight average molecular weight is 41,000, the glass transition temperature. A polylactic acid block copolymer (B-5) at 12.7 ° C. was obtained.

Production Example 9 [Production of polylactic acid block copolymer (B-6)]
A reactor heated to 210 ° C. was charged with 500 g of the polyester (D′-3) obtained in Production Example 3, and sufficiently heated and melted. Subsequently, 550 g of L-PLA was added and uniformly heated and melted and mixed, and titanium tetrabutoxide as a polymerization catalyst was added at 150 ppm to the molten mixture, and the temperature was 200 ° C. and the degree of vacuum was 150 Pa. Reacted for hours. After completion of the reaction, a polyester block having a number average molecular weight of 66,000 and a weight average molecular weight of 111,000 is added to the reaction product obtained by obtaining 2-ethylhexanoic acid phosphate, which is a deactivator for the polymerization catalyst. Copolymer (B-6) (glass transition temperatures: −47.5 ° C. and 55.5 ° C., melting point: 164.5 ° C.) was obtained.

Example 1 [Preparation of polylactic acid resin composition (P-1)]
2400 g of L-PLA, 600 g of the polylactic acid-based block copolymer (B-1) obtained in Production Example 4, trimesic acid tricyclohexylamide (“TF-1” manufactured by Shin Nippon Rika Co., Ltd., average particle size: 3 μm; Hereinafter, it is abbreviated as “TF-1”.) After dry blending 7.5 g, a twin-screw kneading extruder (made by Toyo Seiki Seisakusyo Co., Ltd.) in which the cylinder temperature is set to a temperature in the range of 240 to 250 ° C. ) To obtain a pellet-shaped polylactic acid resin composition (P-1).

Example 2 [Preparation of polylactic acid resin composition (P-2)]
After dry blending 2400 g of L-PLA, 600 g of the polylactic acid block copolymer (B-2) obtained in Production Example 5 and 7.5 g of TF-1, the cylinder temperature was 240 to 250 ° C. Using a twin-screw kneading extruder (manufactured by Toyo Seiki Seisakusho Co., Ltd.) set to a temperature in the range, melt mixing was performed to obtain a polylactic acid resin composition (P-2) in a pellet form.

Example 3 [Preparation of polylactic acid resin composition (P-3)]
After dry blending 2400 g of L-PLA, 600 g of the polylactic acid block copolymer (B-3) obtained in Production Example 6 and 7.5 g of TF-1, the cylinder temperature was 240 to 250 ° C. The mixture was melt-mixed using a twin-screw kneading extruder (manufactured by Toyo Seiki Seisakusho Co., Ltd.) set at a temperature in the range to obtain a polylactic acid resin composition (P-3) in a pellet form.

Example 4 [Preparation of polylactic acid resin composition (P-4)]
After dry blending 2400 g of L-PLA, 600 g of the polylactic acid block copolymer (B-4) obtained in Production Example 7 and 7.5 g of TF-1, the cylinder temperature was 240 to 250 ° C. Using a twin-screw kneading extruder (manufactured by Toyo Seiki Seisakusho Co., Ltd.) set to a temperature in the range, melt mixing was performed to obtain a polylactic acid resin composition (P-4) in the form of pellets.

Comparative Example 1 [Preparation of polylactic acid resin composition (P-5)]
L-PLA was melted and mixed using a twin-screw kneading extruder set at a cylinder temperature in the range of 240 to 250 ° C. to obtain a polylactic acid resin composition (P-5) in the form of pellets.

Comparative Example 2 [Preparation of polylactic acid resin composition (P-6)]
After dry blending 3000 g of L-PLA and 9 g of zinc phenylphosphonate (“PPA-Zn” manufactured by Nissan Chemical Industries, Ltd., average particle size: 3.0 μm; hereinafter abbreviated as “PPA-Zn”) Was melt-mixed using a twin-screw kneading extruder set to a temperature in the range of 240 to 250 ° C. to obtain a polylactic acid resin composition (P-6) in the form of pellets.

Comparative Example 3 [Preparation of polylactic acid resin composition (P-7)]
After dry blending 3000 g of L-PLA and 7.5 g of TF-1, they are melt-mixed using a twin-screw kneading extruder set at a cylinder temperature in the range of 240 to 250 ° C. to form a pellet. A polylactic acid resin composition (P-7) was obtained.

Comparative Example 4 [Preparation of polylactic acid resin composition (P-8)]
After bi-blending 2400 g of L-PLA and 600 g of the polylactic acid block copolymer (B-3) obtained in Production Example 6, the cylinder temperature was set to a temperature in the range of 240 to 250 ° C. It melt-mixed using the kneading extruder, and obtained the polylactic acid resin composition (P-8) which is a pellet form.

Comparative Example 5 [Preparation of polylactic acid resin composition (P-9)]
After bi-blending 2400 g of L-PLA and 600 g of the polylactic acid block copolymer (B-5) obtained in Production Example 8, the cylinder temperature was set to a temperature in the range of 240 to 250 ° C. It melt-mixed using the kneading extruder, and obtained the polylactic acid resin composition (P-9) which is a pellet form.
The numbers in the table are different. Please change from 100 to 80.

Comparative Example 6 [Preparation of polylactic acid resin composition (P-10)]
After dry blending 2400 g of L-PLA, 600 g of the polylactic acid block copolymer (B-5) obtained in Production Example 8, and 9 g of PPA-Zn, the cylinder temperature was in the range of 240 to 250 ° C. The mixture was melt-mixed using a twin-screw kneading extruder set to 1 to obtain a polylactic acid resin composition (P-10) in the form of pellets.

Comparative Example 7 [Preparation of polylactic acid resin composition (P-11)]
2400 g of L-PLA, 600 g of the polylactic acid block copolymer (B-6) obtained in Production Example 9 and 7.5 g of TF-1 were dry blended, and then the cylinder temperature was in the range of 240 to 250 ° C. Was melt-mixed using a twin-screw kneading extruder (manufactured by Toyo Seiki Seisakusho Co., Ltd.) set at a temperature of 1 to obtain a polylactic acid resin composition (P-11) in the form of pellets

  For the polylactic acid resin compositions (P-1) to (P-11) obtained in Examples 1 to 4 and Comparative Examples 1 to 7, crystallization time, cooling time, MIT bending strength, The haze value and bleed resistance were measured, evaluated or calculated. The results and the composition of each polylactic acid resin composition are shown in Tables 2-4.

(Measurement of crystallization time)
The polylactic acid resin composition was vacuum-dried at 80 ° C. for 3 hours, and then heated and melted at 200 ° C. using a heating press to produce a film having a length of 15 cm, a width of 15 cm, and a thickness of 200 μm. A room temperature film cut into a 5 cm × 5 cm square was placed in a dryer at 100 ° C., and the degree of crystallinity was measured over time, and the time required for the degree of crystallinity to be 90% or more was measured. The degree of crystallinity was measured by the DSC method after a film heated for a certain period of time was sandwiched between room temperature presses and rapidly cooled.

[Evaluation of cooling time]
After the polylactic acid resin composition was vacuum-dried at 80 ° C. for 3 hours, the cylinder temperature was 155 ° C. to 185 ° C., the mold temperature using a 1 oz vertical injection molding machine (“SAV30” manufactured by Yamashiro Seiki Co., Ltd.) Bar test piece 13 mm × 130 mm × 6 mm, 15 mm × 130 mm × 3 mm) under the conditions of 110 ° C. and injection time 15 seconds.

  At this time, the cooling time was changed, and the optimum cooling time was determined by checking the state of the molded product that was deformed by protrusion, the state of crystallization by visual observation, and the molded product away from the mold. For example, the cooling time for L-PLA having a number average molecular weight of 94,000 and a weight average molecular weight of 172,000 under the above molding conditions required 30 minutes or more.

[Evaluation of MIT bending strength]
After the polylactic acid resin composition was vacuum-dried at 80 ° C. for 3 hours, a film having a length of 15 cm, a width of 15 cm, and a thickness of 200 μm was produced by heating and melting at 190 ° C. using a heating press and cooling and solidifying. . Using the film, an MIT bending strength test was performed in accordance with JIS P 8115. For example, in PET (A-PET) which is one of general-purpose resins, it is 3,000 times or more in the MIT bending strength test. Therefore, it is practically preferable that it is 3,000 times or more according to the MIT bending strength test.

[Measurement of haze value]
The polylactic acid resin composition was vacuum dried at 80 ° C. for 3 hours, and then heated and melted at 200 ° C. using a heating press to produce a film having a length of 15 cm, a width of 15 cm, and a thickness of 200 μm. The film is cut into a 5 cm × 5 cm square (200 μm thickness), and the haze value on the film surface is measured using a turbidimeter (“ND-1001DP” manufactured by Nippon Denshoku Industries Co., Ltd.) according to JIS K 7105. did. This haze value is referred to as “haze before heating”.

  Furthermore, after putting this film in a 100 degreeC dryer and heating for 5 minutes, the haze value was measured. This haze value is referred to as “haze after heating”.

  In addition, it is practically preferable that the haze value after heating is approximately 50% or less, and it is more preferable that it is practically 10% or less.

[Evaluation of bleed resistance]
Each film (thickness: 200 μm) made of the polylactic acid resin composition prepared by the above method was cut into a 15 cm × 15 cm square, and this film was maintained at 40 ° C. and 90% humidity (manufactured by Espec). , Model PR-2F). Whether or not bleeding occurred on the film surface was visually observed, and the bleeding resistance test was evaluated according to the following criteria.
○: Bleed did not occur even after 120 days.
X: Bleeding occurred within 120 days.

[Calculation of film crystallinity after heating]
10 mg of the film heated by the measurement of haze value (sample for which haze was measured after heating) was put in a measurement container, and increased from 20 ° C. to 210 ° C. at a nitrogen gas flow rate of 50 mL / min and a heating rate of 10 ° C./min using DSC. After heating and holding at 210 ° C. for 3 minutes, the temperature was lowered to −100 ° C. at a cooling rate of 20 ° C./min, and the secondary temperature was raised to 200 ° C. again. Calculate the degree of crystallinity α by the following formula from the peak area of heat of fusion (ΔHm) of the DSC curve drawn at the time of secondary temperature rise and the peak area of heat of crystallization (ΔHc) of the DSC curve drawn at the time of primary temperature rise. did.
Crystallinity α = [(ΔHm−ΔHc) / ΔHm] × 100 (%)

  It was confirmed that the degree of crystallinity of the film other than the polylactic acid resin composition (P-5) was almost 100%. The crystallinity of the polylactic acid resin composition (P-5) was 10%.

  From the above-mentioned Tables 2 to 4, the molded products made of the polylactic acid resin compositions of Examples 1 to 4 were crystallized in comparison with the molded products made of the polylactic acid resin compositions of Comparative Examples 1 to 7. The balance of time, cooling time, MIT folding resistance, haze value before and after heating, and bleed resistance was balanced, and the molding processability and transparency were excellent.

Examples 5-8 and Comparative Examples 7-12
[Production of molded body]
The polylactic acid resin compositions (P-1) to (P-11) obtained in Examples 1 to 4 and Comparative Examples 1 to 7 were dried for 2 hours using a vacuum dryer set at 90 ° C. Thereafter, a film having a thickness of 250 μm was produced using a single-screw extruder provided with a T die (manufactured by Tanabe Plastics Machine Co., Ltd., 50 mmφ, L / D = 36). A film obtained using a vacuum molding machine (FE type manufactured by Hermis Co., Ltd.) can be fitted into a molded body (container with flange) (M-1) having a bottom diameter of 60 mm and a height of 35 mm at a mold temperature of 100 ° C. (M-11) was produced.

[Calculation of crystallinity of molded body]
The crystallinity α was calculated by the same method as the calculation of the crystallinity of the film after heating, except that 10 mg of the molded product produced above was used as a sample.

[Evaluation of molded body condition]
The containers (M-1) to (M-11) made of the polylactic acid composition prepared above were evaluated for molding processability in two stages by state observation. That is, after the mold is cooled for a predetermined time, the mold shape is accurately traced, and when no cracks or cracks are observed, the mold shape is difficult to trace after cooling the mold for a predetermined time or in a container. The case where cracks, cracks, surface roughness, mold release from the mold was difficult, and bleed was observed was rated as x.

  Here, as for vacuum forming, (1) the preheating time may be selected as long as the produced film is softened, and in the present invention, it is appropriately selected within the range of about 2 to 6 seconds. ~ 7, selected with reference to the crystallization time shown in Comparative Examples 1 to 8 and holding the compact in the mold, (3) Cooling time refers to the cooling time for releasing, uniformly 10 seconds did.

  Tables 5 to 8 show the state observation results of the molded bodies made of the polylactic acid resin compositions obtained in Examples 5 to 8 and Comparative Examples 8 to 14.

  From the evaluation results shown in Tables 5 to 7, the polylactic acid resin compositions (P-1) to (P-4) obtained in Examples 1 to 4 were obtained in Comparative Examples 1 to 7. As compared with the polylactic acid resin compositions (P-5) to (P-11), it was found that they were remarkably superior in terms of molding processability and molded quality.

  From the above evaluation results, the molded product obtained by molding using the polylactic acid resin composition of the present invention has excellent crystallinity and moldability, and requires heat resistance and moldability. It is applicable to various fields including food packaging materials.

Claims (13)

A polylactic acid resin composition comprising a polylactic acid (A), a polylactic acid block copolymer (B), and a trimesic acid triamide compound (C) represented by the following general formula (1): The block copolymer (B) is composed of a structural unit (D) other than the polylactic acid structural unit and a polylactic acid structural unit (E) derived from lactic acid having an optical isomerism relationship with the lactic acid constituting the polylactic acid (A). A polylactic acid resin composition characterized by being made.

[R ¹ , R ² and R ³ in the general formula (1) each independently represent a hydrocarbon group. ]   The structural unit (D) is a polyester structural unit obtained by reacting a diol (d1) with a dicarboxylic acid (d2), and / or a diol (d1), a dicarboxylic acid (d2), and a hydroxycarboxylic acid (d3). The polylactic acid resin composition according to claim 1, wherein the polylactic acid resin composition is composed of a polyester structural unit obtained by reacting with.   The polylactic acid resin composition according to claim 2, wherein the polyester structural unit constituting the block copolymer (B) is a structural unit comprising an amorphous polymer.   The polylactic acid resin composition according to any one of claims 1 to 3, wherein the block copolymer (B) has one glass transition temperature (Tg). 5. The polylactic acid resin composition according to claim ¹ , wherein R ¹ , R ² and R ^{3 in the} general formula (1) are each independently an alkyl group having 3 to 14 carbon atoms. . R ¹ , R ² and R ^{3 in the} general formula (1) are each independently an unsubstituted cyclohexyl group or a cyclohexyl group having an alkyl group having 1 to 6 carbon atoms. The polylactic acid resin composition according to claim 1. The R ¹ , R ² and R ^{3 in the} general formula (1) are each independently selected from the group consisting of an n-hexyl group, an n-pentyl group and a cyclohexyl group. The polylactic acid resin composition according to claim 1.   The mass ratio (A / B) between the polylactic acid (A) and the block copolymer (B) is in the range of 90/10 to 30/70. Polylactic acid resin composition.   The said trimesic acid triamide compound (C) contains 0.05-5 mass parts with respect to a total of 100 mass parts of the said polylactic acid (A) and the said polylactic acid-type block copolymer (B). 9. The polylactic acid resin composition according to any one of 8 above.   A polylactic acid resin molded article comprising the polylactic acid resin composition according to any one of claims 1 to 9.   The polylactic acid resin composition according to any one of claims 1 to 9, wherein the polylactic acid resin composition is obtained by injection molding into a mold having a temperature of not less than a glass transition temperature of the polylactic acid resin composition and not higher than 140 ° C. The polylactic acid resin molding as described.   A method for producing a polylactic acid resin molded article, comprising melt-kneading the polylactic acid resin composition according to any one of claims 1 to 9 and then molding under a quenching condition.   After the polylactic acid resin composition according to any one of claims 1 to 9 is melt-extruded into a film, the draw ratio is 1 to 3 in the longitudinal direction (MD direction) and the width direction (TD direction), respectively. A method for producing a polylactic acid resin molded article, which is stretched and then shaped.