JP2010150385A - 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 block copolymer and (C) a trimesic acid triamide compound having a specific structure. The block copolymer (B) is a block copolymer having (D) a polyalkylene ether structural unit and (E) a polyhydroxycarboxylic acid structural unit. <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 using corn and other plants as starting materials, 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., which are described as nucleating agents for lactic acid polymers, are actually used for injection molding, 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 have been made, the compatibility between these aliphatic polyesters and polylactic acid is insufficient, so it has not reached the level of application to various molded products that can withstand bleed and 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 resin 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.

  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.

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 No. W02003 / 042302

  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 intensive studies to solve the above problems, the present inventors have added a block copolymer having a polyalkylene ether structural unit and a polyhydroxycarboxylic acid structural unit to polylactic acid, and further added a specific trimesic acid. It has been found that a polylactic acid resin composition to which a triamide compound has been added can solve the above-mentioned problems, and the present invention has been completed.

  That is, the present invention is a polylactic acid resin composition containing polylactic acid (A), a block copolymer (B), and a trimesic acid triamide compound (C) represented by the following general formula (1). The poly (lactic acid) resin composition, wherein the block copolymer (B) is a block copolymer having a polyalkylene ether structural unit (D) and a polyhydroxycarboxylic acid structural unit (E), The present invention also provides a polylactic acid resin molded article using the resin composition and a method for producing the same.

〔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 such 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 block copolymer (B) used in the present invention is a block copolymer comprising a polyalkylene ether structural unit (D) and a polyhydroxycarboxylic acid structural unit (E). This block copolymer (B) promotes crystallization of polylactic acid (A) and imparts flexibility, impact resistance, heat resistance, and moldability.

  As the form of the block copolymer (B), for example, when the polyalkylene ether structural unit (D) is X and the polyhydroxycarboxylic acid structural unit (E) is Y, an XY type block copolymer, XYX Examples thereof include a mold block copolymer, a random block copolymer, and a mixture thereof. Moreover, as long as the characteristic of a block copolymer (B) is not impaired, these may contain polyalkylene ether, polyhydroxycarboxylic acid, etc. as a non-copolymerization thing.

  Examples of the polyalkylene ether (D ′) that is a raw material of the polyalkylene ether structural unit (D) constituting the block copolymer (B) include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polybutylene diol, Examples thereof include a ring-opening polymer of polyethylene oxide, and a copolymer or mixture of two or more of these.

  The weight average molecular weight of the polyalkylene ether (D ′) by GPC is preferably in the range of 500 to 50,000, more preferably in the range of 1,000 to 40,000, and further in the range of 2,000 to 30,000. preferable.

  Examples of the polyhydroxycarboxylic acid (E ′) that is a raw material of the polyhydroxycarboxylic acid structural unit (E) constituting the block copolymer (B) include lactic acid, glycolic acid, 2-hydroxy-n-butyric acid, Examples include 2-hydroxycaproic acid, 2-hydroxy3,3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, 2-hydroxyisocaproic acid, p-hydroxybenzoic acid, and polycondensates of these mixtures.

  Among the polyhydroxycarboxylic acids (E ′), polylactic acid is preferably used as a main component in order to exhibit the characteristics of the present invention. That is, the content of polylactic acid contained in the polyhydroxycarboxylic acid (E ′) is preferably 50% by mass or more, more preferably 60% by mass or more, and 100% by mass is used. Is more preferable.

  In addition, the polyhydroxycarboxylic acid (E ′) is an L-form, D-form, or a mixture of L-form and D-form when the repeating unit has an asymmetric carbon atom such as polylactic acid (the mixing ratio is particularly Any of racemates can be used.

  When the polyhydroxycarboxylic acid (E ′) is polylactic acid, in order to form a stereocomplex with the polylactic acid (A), when the structural unit of the polylactic acid (A) is L-lactic acid, When the hydroxycarboxylic acid (E ′) is poly (D-lactic acid) and the structural unit of the polylactic acid (A) is D-lactic acid, the polyhydroxycarboxylic acid (E ′) is poly (L-lactic acid). This is preferable because a stereocomplex is formed, crystallization of the polylactic acid resin composition of the present invention is promoted and heat resistance is imparted, and at the same time, a molded product with higher transparency can be obtained.

  The weight average molecular weight of the polyhydroxycarboxylic acid (E ′) by GPC is preferably in the range of 500 to 400,000, more preferably in the range of 5,000 to 400,000, and in the range of 10,000 to 400,000. A range is further preferred, a range of 10,000 to 300,000 is particularly preferred, and a range of 15,000 to 250,000 is most preferred.

  The block copolymer (B) includes a weight ratio of the polyalkylene ether structural unit (D) and the polyhydroxycarboxylic acid structural unit (E) constituting the block copolymer (B) [(D) / (E)] is preferably in the range of 15/85 to 85/15, more preferably in the range of 30/70 to 70/30. It is preferable for obtaining a polylactic acid resin composition having a degree of conversion and bleed resistance.

  The polyalkylene ether structural unit (D) may be crystalline or non-crystalline, but the resulting polylactic acid resin composition has impact resistance, transparency, flexibility, heat resistance, and molding. In order to improve workability, it is preferably non-crystalline.

  Meanwhile, the polyhydroxycarboxylic acid structural unit (E) may be crystalline or non-crystalline.

  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, for example, and the non-crystalline property means that the melting point is not observed by DSC measurement. Say things.

  Moreover, as said block copolymer (B), the thing of the range of the weight average molecular weights 10,000-300,000 is preferable, and a weight average molecular weight 15, from a compatible viewpoint with the said polylactic acid (A). The thing of the range of 000-200,000 is more preferable, and the thing of the range of a weight average molecular weight 20,000-100,000 is especially preferable in order to acquire transparency. By using the block copolymer (B) having a weight average molecular weight within this range, a polylactic acid resin composition having excellent impact resistance, transparency, flexibility, and bleed resistance can be obtained.

  As the block copolymer (B), it is preferable to use one having a glass transition temperature (Tg) measured by DSC according to JIS K 7122 in the range of -80 to 70 ° C. In order to improve the crystallization speed and the crystallinity, 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 polyalkylene ether structural unit (D) constituting the block copolymer (B) and the polyhydroxycarboxylic acid structural unit (E) By using such a block copolymer (B), a polylactic acid resin composition having an excellent crystallization rate can be obtained. As a mechanism excellent in the crystallization rate, it is estimated as follows. The block copolymer (B) finely dispersed in the polylactic acid matrix becomes a polylactic acid crystal nucleus to increase the nucleus growth rate, or the crystal structure of the polylactic acid is the block copolymer (B). It is presumed that the crystallization speed was increased by the plasticization and disorder of the higher order structure.

  Another method for measuring the glass transition temperature (Tg) of the block copolymer (B) is obtained by processing the polylactic acid resin composition of the present invention containing the block copolymer (B). When the dynamic viscoelasticity of the film 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 block copolymer (B). In this case, depending on the processing conditions, for example, the dynamic viscoelasticity of the 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 an external force called stretching, and this peak maximum value corresponds to the glass transition temperature (Tg), and the polyalkylene ether structural unit (D ) And the corresponding polyhydroxycarboxylic acid structural unit (E) are observed.

  Next, the block copolymer (B) can be produced, for example, by the following methods 1 to 3.

  The block copolymer (B) is prepared by, for example, melt-mixing a polyalkylene ether (D ′) and a polyhydroxycarboxylic acid (E ′), and then adding an esterification catalyst and causing an esterification reaction under reduced pressure. (Method 1).

  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 reacting at a temperature in the above-mentioned range, it is possible to suppress the molecular weight decrease, the hue decrease, and the polyhydroxycarboxylic acid (E ′) depolymerization of the block copolymer (B) to be obtained.

  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.

  As said esterification catalyst, the thing similar to what was illustrated as what can be used when manufacturing the polyester mentioned later can be used. The amount of the 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 polyalkylene ether (D ′) and polyhydroxycarboxylic acid (E ′). More preferably, the range of 50 to 200 ppm is particularly preferable. By using the esterification catalyst in such a range, it is possible to obtain a block copolymer (B) having a good hue while suppressing a decrease in the molecular weight of the block copolymer (B).

  The block copolymer (B) is prepared by co-polymerizing the polyalkylene ether (D ′) and the polyhydroxycarboxylic acid (E ′) under reduced pressure conditions in the presence of a high boiling point solvent using an esterification catalyst. It can also be produced by boiling dehydration polycondensation reaction (Method 2).

  Examples of the high boiling point solvent include xylene, anisole, diphenyl ether and the like. 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 the presence of moisture causes a decrease in the molecular weight of the block copolymer (B), the polyalkylene ether (D ′) used in particular should be sufficiently dried before being subjected to the reaction. preferable.

  Further, the block copolymer (B) can be produced by reacting the polyalkylene ether (D ′) with a lactone in the presence of a ring-opening polymerization catalyst (Method 3).

  The method for producing the block copolymer (B) by reacting the polyalkylene ether (D ′) with a lactone in the presence of a ring-opening polymerization catalyst is specifically set at a predetermined temperature in an inert gas atmosphere. In the reaction vessel, the polyalkylene ether (D ′) and the lactone are dissolved or dispersed in a suitable good solvent, homogenized, and then reacted by adding a ring-opening polymerization catalyst. . The reaction temperature is preferably in the range of 150 to 220 ° C, more preferably in the range of 160 to 210 ° C, and particularly preferably in the range of 170 to 200 ° C from the viewpoint of preventing coloring and thermal decomposition of the block copolymer (B).

  Examples of the lactone include lactide, propiolactone, butyrolactone, valerolactone, caprolactone, and a mixture thereof, and lactide is particularly preferable.

  In addition, in order to prevent the ring-opening polymerization reaction between the polyalkylene ether and the lactone due to moisture present in the reaction system and the molecular weight of the resulting block copolymer (B) from being lowered, the polyalkylene ether (D It is preferable to use a material that is sufficiently dried before the reaction to remove water.

  Examples of the solvent that can be used in the method 3 include inert solvents such as toluene. The addition amount of the solvent is preferably in the range of 3 to 30 parts by mass, more preferably in the range of 5 to 30 parts by mass, and 5 to 20 parts by mass with respect to the total amount of the polyalkylene ether (D ′) and the lactone. Further preferred.

  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 polyalkylene ether (D ′) and the lactone. Particularly preferred. If the usage-amount of a ring-opening polymerization catalyst is this range, while suppressing the molecular weight fall of a block copolymer (B), the block copolymer (B) which has a favorable hue can be obtained.

  As the method for producing the block copolymer (B), among the above methods 1 to 3, methods 1 and 3 which do not usually require removal of a large amount of solvent are preferable.

  In addition, the block copolymer (B) may be obtained by, for example, producing a block copolymer (B) obtained by the above-described production method from a polyfunctional polyol, an acid anhydride, a polyvalent isocyanate, an epoxy compound, or a peroxide. It may be a polymer having a high molecular weight by reacting with a product or the like.

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

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

  When a polylactic acid structural unit is used as the polyhydroxycarboxylic acid structural unit (E) constituting the block copolymer (B), the polylactic acid structural unit having an optical isomerism relationship with the lactic acid constituting the polylactic acid (A) is used. When used, a stereocomplex is formed between the polylactic acid (A) and the polylactic acid structural unit. In this case, in addition to the improvement in heat resistance due to the formed stereocomplex, the formed stereocomplex functions as a crystal nucleating agent and is fine as a nucleating agent. Since it is miniaturized, it is effective for maintaining transparency, which is an object of the present invention. Specifically, when L polylactic acid is used as the polylactic acid (A), the polylactic acid structural unit used in the block copolymer (B) is D polylactic acid (methods 1 and 2) or D lactide (method 3). Are introduced in a similar manner.

    Further, a copolymer having a structure other than the polyalkylene ether structural unit (D) may be used as long as the object of the present invention is not impaired. As a method for introducing the structure other than the polyalkylene ether structural unit (D) into the composition, a copolymer in which a part of the polyalkylene ether structure in the copolymer is substituted with another structure may be used, or It is also possible to use a block copolymer substituted with a part of the polyalkylene ether structural unit (D) and a block copolymer not substituted with a structure other than the polyalkylene ether structural unit (D). Examples of the structural unit other than the polyalkylene ether structural unit (D) include a polyester structural unit (F).

  The method for producing a copolymer having a structure other than the polyalkylene ether structural unit (D) is a polymer having a structure other than the polyalkylene ether structural unit (D) among the above-mentioned methods for producing a copolymer. It can be obtained by synthesizing in the same manner by a method in which a part or all of ether (D ′) is replaced.

    The proportion of the structure other than the polyalkylene ether structural unit (D) in the block copolymer is not particularly limited as long as the object of the present invention is not impaired.

  Examples of the polyester into which the polyester structural unit (F) is introduced include polyesters obtained by esterifying dicarboxylic acid and diol, and polyesters (F ') obtained by ring-opening polycondensation of lactones.

  The former polyester is a polyester that can be produced by reacting a diol, a dicarboxylic acid, and a hydroxycarboxylic acid.

  The polyester (F ′) may be crystalline or non-crystalline, but in order to obtain a film or sheet excellent in transparency and moldability, non-crystalline polyester is used. Is preferred. Here, “crystalline polyester” and “non-crystalline polyester” in the present invention are defined by the presence or absence of a melting point. Specifically, “amorphous polyester” refers to a polyester having a heat of fusion of 0 kJ / kg. The melting point is about 10 mg of a polyester film piece that has been conditioned in a standard state using a differential scanning calorimeter “DSC 220C” manufactured by TA Instrumental in accordance with JIS K 7122. It can be determined by measuring from −100 ° C. to 210 ° C. at a gas flow rate of 50 ml / min and a heating rate of 10 ° C./min. A polyester having no endothermic peak within the measurement temperature range can be referred to as an amorphous polyester.

  Moreover, as said polyester (F '), what has an acid value of 10 or less is preferable, it is more preferable that it is 8 or less, and it is especially preferable that it is the range of 0.1-5. When polyester having an acid value in this range is used, a block excellent in molding processability that can suppress unreacted substances by improving the conversion rate of the reaction when producing the block copolymer (B), and is difficult to gel. A copolymer (B) can be obtained.

  When the polyester (F ′) is a so-called random copolymer in which a structural unit derived from a diol and a structural unit derived from a dicarboxylic acid are randomly arranged, a by-product is generated. This is preferable because it can be suppressed and the polyester can have a high molecular weight.

  The polyester (F ′) preferably has a weight average molecular weight in the range of 5,000 to 200,000, more preferably in the range of 5,000 to 200,000, and more preferably in the range of 5,000 to 200,000. It is particularly preferred. A block copolymer having a part of a polyester structural unit derived from a polyester having a weight average molecular weight in this range is an excessive amount of a polyalkylene ether structure without inhibiting the heat resistance and transparency retention, which are the effects of the present invention. There is an advantage that the lowering of the elastic modulus and the deterioration of the impact resistance can be improved.

  Although it does not specifically limit as diol used when manufacturing the said polyester (F '), For example, it is preferable to use aliphatic diol, aromatic diol, and alicyclic diol.

  Examples of the aliphatic diol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,2 -Pentanediol, 1,3-pentanediol, 1,4-pentanediol, 1,5-pentanediol, 2,3-pentanediol, 2,4-pentanediol, 1,2-hexanediol, 1,3- Hexanediol, 1,4-hexanediol, 1,5-hexanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decane Diol, 1,11-undecanediol, 1,12-dodecanediol, 1,4-cyclohexanedimethanol, neo Nthyl glycol, 3,3-diethyl-1,3-propanediol, 3,3-dibutyl-1,3-propanediol, 2-methyl-2,4-pentanediol, n-butoxyethylene glycol, dimer acid diol Diethylene glycol, dipropylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, xylylene glycol, phenylethylene glycol, and the like can be used.

  As the aromatic diol, an ethylene oxide adduct or propylene oxide adduct of bisphenol A can also be used. Examples of the alicyclic diol include cyclohexanedimethanol and hydrogenated bisphenol A.

Although said diol can also be used independently, 2 or more types can also be used together. For example, the combined use of 1,2-propanediol and polyethylene glycol, the combined use of ethylene glycol and 1,4-butanediol, and the like can be mentioned.
above

  Examples of the dicarboxylic acid used for producing the polyester (F ′) include oxalic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, and cyclohexanedicarboxylic acid. And aliphatic dicarboxylic acids such as dimer acid, unsaturated aliphatic dicarboxylic acids such as fumaric acid, succinic anhydride, adipic anhydride, phthalic acid, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid and the like. These can be used alone or in combination of two or more.

  Further, it is possible to use a hydroxycarboxylic acid as long as the effects of the present invention are not impaired when the polyester (F ′) is produced. The hydroxycarboxylic acid is not particularly limited as long as it is a compound having a hydroxyl group and a carboxyl group in one molecule. For example, lactic acid, glycolic acid, 2-hydroxy-n-butyric acid, 2-hydroxycaproic acid, Examples include 2-hydroxy-3,3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, 2-hydroxyisocaproic acid, and p-hydroxybenzoic acid. These can be used alone or in combination of two or more. When a hydroxycarboxylic acid having an optical isomer is used, any of D-form, L-form, and racemate can be used. The hydroxycarboxylic acid may be solid or liquid, and may be used as an aqueous solution.

  As the hydroxycarboxylic acid, it is easy to use lactic acid or glycolic acid, the reaction control when producing the polyester (F ′) is easy, a dimer or a 3 amount of polyester. It is preferable because generation of by-products such as body can be greatly suppressed. Moreover, it is easy to adjust the molecular weight of the obtained polyester to a relatively high molecular weight by using the hydroxycarboxylic acid.

  The manufacturing method of the said polyester (F ') is not specifically limited, For example, the esterification catalyst is used for the said diol, dicarboxylic acid, its anhydride or its esterified product, and the said hydroxycarboxylic acid as needed. Thus, it can be produced by esterification by a known and usual esterification reaction. At that time, in order to suppress the coloring of the polyester, an antioxidant such as a phosphite compound, the total amount of the diol, dicarboxylic acid, its anhydride or esterified product, and the hydroxycarboxylic acid, It is preferable to use in the range of 10 to 2000 ppm.

  The hydroxycarboxylic acid may be an esterification reaction by mixing diol, dicarboxylic acid, anhydride or esterified product thereof, and hydroxycarboxylic acid, but the diol and dicarboxylic acid, anhydride thereof or the diol may be mixed. After reacting in advance with the esterified product, hydroxycarboxylic acid may be mixed and esterified.

  The combination of the diol and the dicarboxylic acid is not particularly limited, but a combination of a diol having 3 to 8 carbon atoms and a dicarboxylic acid having 4 to 12 carbon atoms is preferable.

  As the esterification catalyst, it is preferable to use a catalyst composed of at least one metal selected from the group consisting of Groups 2, 3, and 4 of the periodic table, or a metal compound thereof. Examples of the metal include metals such as Ti, Sn, Zn, Al, Zr, Mg, Hf, and Ge. Examples of the metal compound include titanium tetraisopropoxide, titanium tetrabutoxide, titanium oxyacetylacetonate, tin octoate, 2-ethylhexanetin, acetylacetonate zinc, zirconium tetrachloride, and tetrachlorotetrahydrofuran complex. Examples include hafnium tetrachloride, hafnium tetrachloride tetrahydrofuran complex, germanium oxide, and tetraethoxygermanium.

  The amount of the esterification catalyst used is usually an amount that can control the reaction and obtain good quality, and is generally 10 to 1000 ppm based on the total amount of diol, dicarboxylic acid and hydroxycarboxylic acid. The range is preferable, the range of 20 to 800 ppm is more preferable, and the range of 30 to 500 ppm is particularly preferable from the viewpoint of reducing the coloration of the polyester (II ′).

  The esterification catalyst may be added when the raw materials such as diol and dicarboxylic acid are charged, or may be added before the reaction system is depressurized.

  In addition, the esterification catalyst may be deactivated by a publicly known method after the production of the polyester (F ′), which causes a side reaction during melt mixing with the polylactic acid or lactone described later. It is preferable because it can be suppressed. As a method for deactivating the esterification catalyst, for example, there is a method using a chelating agent.

  As the chelating agent, a known and commonly used organic chelating agent or inorganic chelating agent 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 nitrogen as a coordinating atom. Examples thereof include phenols having atoms and carboxylic acids. Examples of the inorganic chelating agent include phosphorus compounds such as phosphoric acid, phosphoric acid ester, phosphorous acid, and phosphorous acid ester.

  Further, the polyester is made to have a branched chemical structure by reacting the polyester with an acid anhydride, a polyvalent isocyanate, a peroxide, etc. before and after the addition of the deactivator for the esterification catalyst, thereby obtaining a polyester having a higher molecular weight. You can also

  The temperature for producing the polyester (F ′) is preferably in the range of 150 to 260 ° C., and more preferably in the range of 180 to 230 ° C. The polymerization time for producing the polyester 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 is preferably 133 kPa or less, and more preferably 0.26 kPa or less.

  The trimesic acid triamide compound (C) used in the present invention is a compound 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 block copolymer (B), and serves as a crystal nucleating agent for promoting the crystallization thereof. It acts effectively, and contributes to improvement of the crystallization speed and crystallinity of the resulting polylactic acid resin composition, that is, improvement of heat resistance and molding processability. Furthermore, it is also effective in improving the transparency that usually deteriorates as crystallization progresses.

Examples of the alkyl group (R ¹ , R ² , R ³ ) of the trimesic acid triamide compound represented by the general formula (1) include a methyl group, an ethyl group, a propyl group, an isopropyl group, and an n-butyl group. , Isobutyl group, second butyl group, third butyl group, n-amyl group, third amyl group, hexyl group, heptyl group, n-octyl group, 2-ethylhexyl group, third octyl group, nonyl group, decyl group , Undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, octadecenyl group, 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. The n-pentyl group and n-hexyl group, which is a linear alkyl group having 5 or 6 carbon atoms, is most preferable.

  These trimesic acid triamide compounds can be used alone or in combination. A trimesic acid triamide compound having a hydrocarbon group other than an alkyl group can also be used in combination as long as the effects of the present invention are not impaired.

  Examples of the hydrocarbon group other than the alkyl group include an alicyclic group and an aromatic group. For example, the alicyclic group includes a 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-butylcyclohexyl Base 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 Cyclohexyl group optionally having an alkyl group having 1 to 6 carbon atoms such as 2,4,6-trimethylcyclohexyl group, 3,4,5-trimethylcyclohexyl group, etc., and other alicyclic groups As cyclopropyl group, cyclobutyl group, cyclope Tyl group, cycloheptyl group, cyclooctyl group, cyclododecyl group, cyclohexylmethyl group, methylcyclohexylmethyl group, dimethylcyclohexylmethyl group, trimethylcyclohexylmethyl group, methoxycyclohexylmethyl group, ethoxycyclohexylmethyl group, dimethoxycyclohexylmethyl group, chloro Cyclohexylmethyl group, dichlorocyclohexylmethyl group, α-cyclohexylethyl group, β-cyclohexylethyl group, methoxycyclohexylethyl group, dimethoxycyclohexylethyl group, chlorocyclohexylethyl group, dichlorocyclohexylethyl group, α-cyclohexylpropyl group, β-cyclohexyl Examples thereof include a propyl group, a γ-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, and a methyl group. Benzyl group, dimethylbenzyl group, trimethylbenzyl group, methoxybenzyl group, ethoxybenzyl group, dimethoxybenzyl group, chlorobenzyl group, dichlorobenzyl group, α-phenylethyl group, β-phenylethyl group, methoxyphenylethyl group, dimethoxyphenyl Examples include an ethyl group, a chlorophenylethyl group, a dichlorophenylethyl group, an α-phenylpropyl group, a β-phenylpropyl group, a γ-phenylpropyl group, and a methylphenylpropyl group.

  Among the above 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 regardless of whether it is linear or branched. More preferred is an n-pentyl group or n-hexyl group which is a linear alkyl group having 5 or 6 carbon atoms. A cyclohexyl group is preferable as the hydrocarbon other than the alkyl group.

  The trimesic acid triamide compound (C) amidates trimesic acid or an acid chloride thereof and a cyclohexylamine which may have a linear or branched alkyl group having 1 to 6 carbon atoms. Can be obtained.

  These trimesic acid triamide compounds can be used alone or in combination of two or more. A trimesic acid triamide compound having a hydrocarbon group other than an alkyl group can also be used in combination as long as the effects of the present invention are not impaired.

  Further, the shape of the trimesic acid triamide compound in the polylactic acid resin composition of the present invention is not particularly limited, but the solubility at the time of melt-kneading the polylactic acid (A) and the block copolymer (B) is good. As a result of improving the nucleating action and the transparency to 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 0.01 to 30 μm. It is preferably in the range of powder.

  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 polylactic acid crystals produced or controlling the proportion of crystals produced, whereas transparency usually deteriorates as crystallization progresses. The

  In the polylactic acid resin composition of the present invention, the weight ratio (A) / (B) of the polylactic acid (A) and the block copolymer (B) is in the range of 95/5 to 30/70. It is more 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.

  In the polylactic acid resin composition of the present invention, the trimesic acid triamide compound (C) is 0.05 to 5 parts by mass with respect to the total amount of the polylactic acid (A) and the block copolymer (B). In order to uniformly dissolve the trimesic acid triamide compound (C) in the polylactic acid (A) and the block copolymer (B) for more effective crystal nucleus growth, 0 is preferable. It is more preferable to contain in the range used as 10-10 mass parts.

  Here, the following consideration holds as theoretical knowledge about the addition amount of the trimesic acid triamide compound as the trimesic acid triamide compound (C). 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
(1) Polylactic acid (A), block copolymer (B) and trimesic acid triamide compound (C) are mixed with an appropriate mixer, and heated and melt-kneaded with a single-screw or multi-screw extruder having sufficient kneading ability. how to,
(2) After heat-melt-kneading polylactic acid (A) and block copolymer (B), trimesic acid triamide compound (C) and other additives as necessary are supplied, and a high-speed stirrer or low-speed stirrer After uniformly mixing using, etc., a method of heat-melting and kneading with a single-screw or multi-screw extruder having sufficient kneading ability,
(3) a so-called masterbatch in which a small amount of polylactic acid (A), an excess block copolymer (B) and an excess trimesic acid triamide compound (C) are mixed and melt-kneaded in an appropriate mixer; Polylactic acid (A) can be produced by a method such as heat 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 and then the solvent is removed.

  As a more specific production method of the polylactic acid resin composition of the present invention, in addition to the above-mentioned three production methods, the trimesic acid triamide compound (C) is added to the polylactic acid (A) and the block copolymer (B). Examples thereof include a method of melt-kneading until the trimesic acid triamide compound (C) is uniformly dispersed at a temperature equal to or higher than a melting temperature (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.

  Since the trimesic acid triamide compound represented by the general formula (1) used as the trimesic acid triamide compound (C) in the present invention generally has a melting point in the range of 180 to 400 ° C., the polylactic acid (A) and the block When the copolymer (B) and the trimesic acid triamide compound are melt-kneaded, the polylactic acid (A) and the block copolymer (B) are first melted, and then the trimesic acid triamide compound is blocked with the polylactic acid (A). Dissolves in copolymer (B). Here, the melting temperature is preferably in the range of 190 to 260 ° C., more preferably in the range of 200 to 255 ° C., which suppresses thermal decomposition of the polylactic acid (A) and the block copolymer (B), and the trimesic acid triamide compound is In order to disperse more uniformly, it is particularly preferable to dissolve in the range of 210 to 250 ° C.

  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 block copolymer (B) is not 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 pt-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′-diphenylterephthal Amide, N, N′-diphenylsuccinamide, N, N′-diphenylsuberamide, sodium salt of bis (3,5-di-t-butyl-2-phosphophenyl) methane, di-t-butylaluminum In the case of benzoate and aliphatic carboxylic acid, palmitic acid amide and stearic acid , 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 carboxylic acid as aliphatic carboxylate Examples of the 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.

  The film referred to in the present invention is not limited in terms of its shape, size, thickness, design, and the like. 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 1.00 to 3.00 times in the longitudinal and transverse directions.

  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 treatment in a state in which the film is stretched within a range that does not impair the 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 body.

  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 weight attached to the clip is attached to one end of the test piece (the gripping part of the clip is 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, the weight of the polyhydroxycarboxylic acid structural unit and the polyester structural unit constituting the block copolymer is analyzed by analyzing a chloroform-d (CDCl ₃ ) solution of the block copolymer using the same apparatus as described above. The composition ratio (% by mass) was calculated.

Production Example 1 [Production of polyester (1)]
A reactor was charged with 1000 g of sebacic acid (hereinafter abbreviated as “SeA”) and 414 g of propylene glycol (hereinafter abbreviated as “PG”), and the temperature was increased from 150 ° C. to 20 ° C. per hour under a nitrogen stream. Then, the esterification reaction was carried out by heating and stirring to 230 ° C. while distilling off the generated water. 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 is added to the obtained polyester as a deactivator for the polymerization catalyst, whereby the polyester having a number average molecular weight of 43,000 and a weight average molecular weight of 60,000 (1) Got. The acid value of the polyester (1) 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%). there were.

Production Example 2 [Production of polyester (2)]
A reactor was charged with 1000 g of succinic acid (hereinafter abbreviated as “SuA”) and 696 g of PG, and the temperature was raised from 150 ° C. to 20 ° C. per hour under a nitrogen stream to 220 ° C. while distilling off the generated water. The esterification reaction was carried out with heating and stirring. 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 as a deactivator for the polymerization catalyst is added to the obtained polyester to obtain a polyester having a number average molecular weight of 15,000 and a weight average molecular weight of 24,000 (2) Got. The acid value of the polyester (2) 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%). there were.

Production Example 3 [Production of Block Copolymer (B-1)]
The reactor was charged with 50 g of polyethylene glycol (“PEG-20000” manufactured by Sanyo Chemical Industries, Ltd., number average molecular weight: 20,000, hydroxyl value: 5.6 mg KOH / g; hereinafter abbreviated as “PEG”). Heating was performed at a jacket temperature of 200 ° C. in a nitrogen atmosphere. Thereafter, 55 g of L-polylactic acid (“Lacia H-400” manufactured by Mitsui Chemicals, Inc .: number average molecular weight 92,000, weight average molecular weight 170,000; hereinafter abbreviated as “L-PLA”) was added. And melt mixed. After visually confirming that PEG and L-PLA were uniformly melt-mixed, the mixture was further melt-mixed for 2 hours. Subsequently, 200 ppm of titanium tetrabutoxide was added as an esterification catalyst with respect to the total amount of the molten mixture, and reacted at a reduced pressure of 80 Pa for 4 hours. After completion of the reaction, as a deactivator for the esterification catalyst, 2-ethylhexanoic acid phosphate is added at 500 ppm with respect to the total amount of the reaction product, and a block copolymer having a number average molecular weight of 44,000 and a weight average molecular weight of 56,000. The union (B-1) was obtained. The glass transition temperature was 4 ° C.

Production Example 4 [Production of Block Copolymer (B-2)]
The reactor was charged with 50 g of the polyester (1) obtained in Production Example 1, and heated at a jacket temperature of 200 ° C. in a nitrogen atmosphere. Thereafter, 55 g of L-PLA was added and melt mixed. After visually confirming that the polyester (1) and L-PLA were uniformly melt-mixed, they were further melt-mixed for 2 hours. Subsequently, 200 ppm of titanium tetrabutoxide was added as an esterification catalyst with respect to the total amount of the molten mixture, and reacted at a reduced pressure of 80 Pa for 4 hours. After completion of the reaction, as a deactivator for the esterification catalyst, 2-ethylhexanoic acid phosphate is added at 500 ppm with respect to the total amount of the reaction product, and the block copolymer weight having a number average molecular weight of 66,000 and a weight average molecular weight of 111,000. A union (B-2) (glass transition temperature: −47.5 ° C., 55.5 ° C.) was obtained.

Production Example 5 [Production of Block Copolymer (B-3)]
A reactor was charged with 25 g of PEG and 25 g of the polyester (2) obtained in Production Example 2 was charged and heated at a jacket temperature of 200 ° C. in a nitrogen atmosphere. Thereafter, 55 g of L-PLA was added and melt mixed. After visually confirming that PEG, polyester (2) and L-PLA were uniformly melt-mixed, they were melt-mixed for another 2 hours. Subsequently, 200 ppm of titanium tetrabutoxide was added as an esterification catalyst with respect to the total amount of the molten mixture, and reacted at a reduced pressure of 80 Pa for 4 hours. After completion of the reaction, as a deactivator of the esterification catalyst, 2-ethylhexanoic acid phosphate is added at 500 ppm with respect to the total amount of the reaction product, and a block copolymer having a number average molecular weight of 48,000 and a weight average molecular weight of 58,000. A union (B-3) (glass transition temperature: 7.5 ° C.) was obtained.

Production Example 6 [Production of Block Copolymer (B-4)]
The reactor was charged with 50 g of PEG and heated at a jacket temperature of 200 ° C. in a nitrogen atmosphere. Thereafter, 55 g of D-polylactic acid (number average molecular weight 90,000, weight average molecular weight 164,000) was added and melt mixed. After visually confirming that PEG and D-polylactic acid were uniformly melt-mixed, the mixture was further melt-mixed for 2 hours. Subsequently, 200 ppm of titanium tetrabutoxide was added as an esterification catalyst with respect to the total amount of the molten mixture, and reacted at a reduced pressure of 80 Pa for 4 hours. After completion of the reaction, as a deactivator for the esterification catalyst, 2-ethylhexanoic acid phosphate is added at 500 ppm with respect to the total amount of the reaction product, and a block copolymer having a number average molecular weight of 41,000 and a weight average molecular weight of 63,000. A coalescence (B-4, glass transition temperature 4 ° C.) was obtained.

Example 1 [Preparation of polylactic acid resin composition (P-1)]
2400 g of L-PLA, 600 g of the block copolymer (B-1) obtained in Production Example 3, trimesic acid tricyclohexylamide (“TF-1” manufactured by Shin Nippon Rika Co., Ltd., average particle diameter: 3 μm; TF-1 "is omitted.) After 7.5 g of dry blending, a twin-screw kneading extruder (manufactured by Toyo Seiki Seisakusho Co., Ltd.) in which the cylinder temperature is set to a temperature in the range of 240 to 250 ° C is used. Were melt-mixed to obtain a polylactic acid resin composition (P-1) in the form of pellets.

Example 2 [Preparation of polylactic acid resin composition (P-2)]
After dry blending 2400 g of L-PLA, 600 g of the block copolymer (B-3) obtained in Production Example 5 and 7.5 g of TF-1, the cylinder temperature was in the range of 240 to 250 ° C. A polylactic acid resin composition (P-2) in the form of pellets was obtained by melt-mixing using a biaxial kneading extruder set to 1.

Example 3 [Preparation of polylactic acid resin composition (P-3)]
After dry blending 2400 g of L-PLA, 600 g of the block copolymer (B-4) obtained in Production Example 6 and 7.5 g of TF-1, the cylinder temperature was in the range of 240 to 250 ° C. A polylactic acid resin composition (P-3) in the form of pellets was obtained by melt-mixing using a biaxial kneading extruder set to 1.

Example 4 [Preparation of polylactic acid resin composition (P-4)]
2400 g of L-PLA, 600 g of the block copolymer (B-1) obtained in Production Example 3, and 30 g of trimesic acid tri-n-pentylamide (average particle size of 3 μm; hereinafter abbreviated as “TP”). After dry blending, they were melt-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-4) in the form of pellets. It was.

Example 5 [Preparation of polylactic acid resin composition (P-5)]
6. L-PLA 2400 g, block copolymer (B-1) 600 g obtained in Production Example 3, trimesic acid tri-n-hexylamide (average particle size 3 μm; hereinafter abbreviated as “TH”) After dry blending with 5 g, they were melt-mixed using a twin-screw kneading extruder set at a cylinder temperature in the range of 240 to 250 ° C., and pelletized polylactic acid resin composition (P-5) Got.

Comparative Example 1 [Preparation of polylactic acid resin composition (P-6)]
L-PLA was melted and mixed using a twin-screw kneading extruder in which the cylinder temperature was set to a range of 240 to 250 ° C. to obtain a polylactic acid resin composition (P-6) in the form of pellets.

Comparative Example 2 [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 3 [Preparation of polylactic acid resin composition (P-8)]
After dry blending 2400 g of L-PLA and 600 g of the block copolymer (B-1) obtained in Production Example 3, a twin-screw kneading extruder in which the cylinder temperature was set to a temperature in the range of 240 to 250 ° C. The resulting mixture was melt-mixed to obtain a pellet-shaped polylactic acid resin composition (P-8).

Comparative Example 4 [Preparation of polylactic acid resin composition (P-9)]
After dry blending 2400 g of L-PLA and 600 g of the block copolymer (B-4) obtained in Production Example 6, a twin-screw kneading extruder in which the cylinder temperature was set to a temperature in the range of 240 to 250 ° C. The resulting mixture was melt-mixed to obtain a pellet-shaped polylactic acid resin composition (P-9).

Comparative Example 5 [Preparation of polylactic acid resin composition (P-10)]
After dry blending 2400 g of L-PLA, 600 g of the block copolymer (B-2) obtained in Production Example 4 and 7.5 g of TF-1, 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 6 [Preparation of polylactic acid resin composition (P-11)]
2400 g of L-PLA, 600 g of the block copolymer (B-1) obtained in Production Example 3, zinc phenylphosphonate (“PPA-Zn” manufactured by Nissan Chemical Industries, Ltd., average particle size: 3.0 μm; (It is abbreviated as “PPA-Zn.”) After 9 g of dry blending, they were 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-11) was obtained.

Comparative Example 7 [Preparation of polylactic acid resin composition (P-12)]
2700 g of L-PLA, 300 g of benzoic acid plasticizer (“LA-100” manufactured by Nippon Nippon Chemical Co., Ltd., dibenzoate ester of polyethylene glycol having a molecular weight of 200; hereinafter abbreviated as “LA-100”), and TF -1 After 7.5 g of dry blending, they were melt-mixed using a twin-screw kneading extruder set at a cylinder temperature in the range of 240 to 250 ° C. to obtain a polyester composition (P- 12) was obtained.

Comparative Example 8 [Preparation of polylactic acid resin composition (P-13)]
After dry blending 2700 g of L-PLA, 300 g of adipic acid-based plasticizer (“SN0213” manufactured by Daihachi Chemical Co., Ltd .; hereinafter abbreviated as “SN0213”) and 7.5 g of TF-1, they were added to a cylinder. The mixture was melt-mixed using a twin-screw kneading extruder set at a temperature in the range of 240 to 250 ° C. to obtain a polyester composition (P-13) in the form of pellets.

  For the polylactic acid resin compositions (P-1) to (P-13) obtained in Examples 1 to 5 and Comparative Examples 1 to 8, 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 1 to 3.

(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-6) was almost 100%. The crystallinity of the polylactic acid resin composition (P-6) was 10%.

  From the above Tables 1 to 3, the molded products made of the polylactic acid resin compositions of Examples 1 to 5 were crystallized compared to the molded products made of the polylactic acid resin compositions of Comparative Examples 1 to 8. 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 6-10 and Comparative Examples 9-18
[Production of molded body]
The polylactic acid resin compositions (P-1) to (P-13) obtained in Examples 1 to 5 and Comparative Examples 1 to 8 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-13) 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-13) 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. (2) The mold holding time is as in Example 1. -5, selected with reference to the crystallization time shown in Comparative Examples 1-8, and holding the molded body in the mold, (3) Cooling time refers to the cooling time for releasing, uniformly 10 seconds did.

  Tables 4 to 6 show the state observation results of the molded bodies made of the polylactic acid resin compositions obtained in Examples 6 to 10 and Comparative Examples 9 to 16.

  From the evaluation results shown in Tables 4 to 6, the polylactic acid resin compositions (P-1) to (P-5) obtained in Examples 1 to 5 were obtained in Comparative Examples 1 to 8. As compared with the polylactic acid resin compositions (P-6) to (P-13), 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. Therefore, it can be applied to various fields including food packaging materials.

Claims (13)

A polylactic acid resin composition containing polylactic acid (A), a block copolymer (B), and a trimesic acid triamide compound (C) represented by the following general formula (1), wherein the block copolymer The polylactic acid resin composition, wherein the polymer (B) is a block copolymer having a polyalkylene ether structural unit (D) and a polyhydroxycarboxylic acid structural unit (E).

[R ¹ , R ² and R ³ in the general formula (1) each independently represent a hydrocarbon group. ]   The polylactic acid resin composition according to claim 1, wherein the block copolymer (B) has one glass point transfer (Tg). The polylactic acid resin composition according to claim 1 or 2, 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 as a substituent. The polylactic acid resin composition according to claim 1 or 2. ^3. 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 n-hexyl group or an n-pentyl group.   The polyhydroxycarboxylic acid structural unit (E) constituting the block copolymer (B) is selected from the group consisting of a structural unit derived from glycolic acid, a structural unit derived from lactic acid, and a structural unit derived from hydroxycaproic acid It is the above structural unit, The polylactic acid resin composition of any one of Claims 1-5.   The polyhydroxycarboxylic acid structural unit (E) constituting the block copolymer (B) is a polylactic acid structural unit derived from lactic acid having an optical isomerism relationship with lactic acid constituting the polylactic acid (A). The polylactic acid resin composition according to any one of 1 to 5.   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 trimesic acid triamide compound (C) is contained in an amount of 0.05 to 5 parts by mass with respect to a total of 100 parts by mass of the polylactic acid (A) and the polylactic acid block copolymer (B). 2. The polylactic acid resin composition according to 2.   A polylactic acid resin molded article comprising the polylactic acid resin composition according to any one of claims 1 to 9.   Polylactic acid resin molding obtained by injection-molding the polylactic acid resin composition according to any one of claims 1 to 9 into a mold having a temperature of not less than the glass transition temperature of the polylactic acid resin composition and not higher than 140 ° C. body.   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.