JP2005325291A - High impact resistance polylactic acid composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polylactic acid composition excellent in heat resistance and impact resistance, and to provide a molded article obtained by using the composition. <P>SOLUTION: This polylactic acid composition contains (A) polylactic acid, (B) a polylactic acid copolymer having a polylactic acid structural unit (I) and a polyester structural unit (II) derived from a diol and a dicarboxylic acid including dimer acid and (C) a filler having a mean particle size of 0.05 to 3 μm, and has a microphase-separated structure in which the polylactic acid (A) forms a domain in a matrix formed by the copolymer (B). Further, the composition satisfied the following formula: [wt% of the filler (C) present in the matrix based on 100 pts.wt. thereof]-[wt% of the copolymer (B) based on 100 pts.wt. of total of the polylactic acid (A) and copolymer (B)]=5 to 80 wt%. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a polylactic acid composition excellent in heat resistance, impact resistance and flexibility.

  Since polylactic acid can be synthesized from natural raw materials such as corn and has excellent transparency, biodegradability, and moldability, it has attracted attention as an environmentally conscious resin, particularly a molding resin. However, polylactic acid is very brittle because of poor heat resistance, impact resistance, and flexibility, and has problems in workability, so that industrial applications are limited.

  As a method for solving such a problem, for example, a method of mixing an impact resistance imparting agent made of a lactic acid-based polyester having a weight average molecular weight of 10,000 or more and a glass transition temperature of 60 ° C. or less into polylactic acid, and the like are mentioned. According to the method, it has been reported that impact resistance and flexibility can be imparted to polylactic acid (for example, see Patent Document 1).

  On the other hand, it has been reported that a lactic acid polymer composition comprising polylactic acid, a layered silicate and a lactic acid polyester is excellent in heat resistance and impact strength (see, for example, Patent Document 2).

  The industry has demanded the development of a polylactic acid composition having a superior impact resistance than ever before, and in particular, if a polylactic acid composition having an impact resistance to the extent that it can be used as an automobile exterior part can be developed, The industrial use of polylactic acid can be further expanded. However, none of the polylactic acid compositions described in Patent Documents 1 and 2 are still satisfactory in terms of impact resistance to be applied as automobile exterior parts.

JP-A-2001-335623 (Claims 1 and 7) JP 2002-363393 A (Claim 1)

  The problem to be solved by the present invention is to provide a polylactic acid composition excellent in heat resistance and impact resistance and a molded product obtained using the same.

  The present inventors have made impact resistance by mixing various fillers with a polylactic acid composition having a microphase-separated structure in which polylactic acid forms domains in a matrix formed by a polylactic acid copolymer that can impart impact resistance. We thought that it was possible to obtain a polylactic acid composition excellent in the above, and have made extensive studies.

  However, even when a filler having an average particle diameter of about 10 μm, which has been generally used, has been used, it has not been possible to obtain a polylactic acid composition having an impact resistance that can be used as an automobile exterior part.

  Therefore, by using a filler with a smaller average particle size than before, the affinity between the filler and polylactic acid was improved, and the impact resistance could be drastically improved, but it was used as an automotive exterior part. A polylactic acid composition having a sufficient impact resistance could not be obtained.

  Therefore, when the filler is not uniformly dispersed in the polylactic acid composition, but a specific amount of filler is dispersed in the matrix, it has a superior impact resistance and heat resistance that can be used as an automobile exterior part. A lactic acid composition could be obtained.

  That is, the present invention provides a polylactic acid (A), a polylactic acid copolymer (B) having a polylactic acid structural unit (I) and a polyester structural unit (II) derived from a diol and a dicarboxylic acid containing a dimer acid. And a polylactic acid composition containing 5 to 30% by weight of filler (C) having an average particle size of 0.05 to 3 μm, wherein the polylactic acid copolymer (B) forms the matrix. The polylactic acid (A) has a microphase-separated structure forming a domain, and [the weight ratio of the filler present in the matrix to 100 parts by weight of the filler (C)-the polylactic acid (A) and the The weight ratio of the polylactic acid copolymer (B) to the total 100 parts by weight of the polylactic acid copolymer (B)] is from 5 to 80% by weight. Preferably, the filler (C) is talc having an average particle size of 0.1 to 3 μm, calcium carbonate having an average particle size of 0.1 to 2 μm, or a layered silicate having an average particle size of 0.05 to 0.5 μm. It is related with the polylactic acid composition which is.

  The present invention also relates to a molded product obtained using the polylactic acid composition.

  The polylactic acid composition of the present invention is excellent in impact resistance and heat resistance, hardly causes bleed out, has excellent flexibility, and can be used as an automobile exterior part, a housing for home appliances, and the like. .

  The present invention provides a polylactic acid (A), a polylactic acid copolymer (B) having a polylactic acid structural unit (I), a polyester structural unit (II) derived from a diol and a dicarboxylic acid containing a dimer acid, and A polylactic acid composition containing 5 to 30% by weight of filler (C) having an average particle size of 0.05 to 3 μm, wherein the polylactic acid is formed in the matrix formed by the polylactic acid copolymer (B). Lactic acid (A) has a microphase-separated structure in which a domain is formed, and [weight ratio of the filler present in the matrix to 100 parts by weight of the filler (C) -the polylactic acid (A) and the poly The weight ratio of the polylactic acid copolymer (B) to the total 100 parts by weight of the lactic acid copolymer (B)] is 5 to 80% by weight.

  The polylactic acid (A) used in the present invention is a poly (L-lactic acid) whose structural unit is L-lactic acid, a poly (D-lactic acid) whose structural unit is D-lactic acid, a structural unit that is L-lactic acid, and Poly (DL-lactic acid) which is D-lactic acid or a mixture thereof. The weight average molecular weight of the polylactic acid (A) is preferably in the range of 100,000 to 400,000 in order to have molding processing characteristics and mechanical characteristics. The polylactic acid (A) may be modified with an acid anhydride such as maleic anhydride, pyromellitic anhydride or trimellitic anhydride as necessary.

  Next, the polylactic acid copolymer (B) used in the present invention will be described.

  The polylactic acid copolymer (B) used in the present invention has a polylactic acid structural unit (I), a polyester structural unit (II) derived from a diol and a dicarboxylic acid containing a dimer acid, By mixing with the polylactic acid (A), a polylactic acid composition excellent in impact resistance and heat resistance and excellent in mechanical strength such as flexibility and flexural modulus can be obtained.

  The polylactic acid structural unit (I) is obtained using lactide (I ′) or polylactic acid (I ″).

  Lactide (I ′) is a compound obtained by cyclic dimerization of two lactic acid molecules by dehydration condensation, and has a stereoisomer, L-lactide consisting of two L-lactic acid molecules, and D consisting of two D-lactic acid molecules. -Lactide, and meso-lactide composed of D-lactic acid and L-lactic acid. In particular, a copolymer containing only L-lactide or D-lactide has a high melting point, and preferable resin characteristics can be realized by combining these three types of lactide in various proportions depending on the application.

  When the constituent ratio of L-lactide and D-lactide in the polylactic acid structural unit (I) is extremely different from the constituent ratio of L-lactic acid and D-lactic acid in the polylactic acid (A), for example, a polylactic acid structure When the unit (I) is derived from D-lactide and the polylactic acid (A) is poly (L-lactic acid), a polylactic acid composition having a high melting point and excellent mechanical properties such as heat resistance and flexural modulus is obtained. be able to.

  Polylactic acid (I ″) means poly (L-lactic acid) whose structural unit is L-lactic acid, poly (D-lactic acid) whose structural unit is D-lactic acid, structural units that are L-lactic acid and D-lactic acid Poly (DL-lactic acid) or a mixture thereof. When the constituent ratio of D-lactic acid and L-lactic acid in the polylactic acid structural unit (I) is extremely different from the constituent ratio of L-lactic acid and D-lactic acid in the polylactic acid (A), for example, a polylactic acid structural unit When (I) is derived from poly (D-lactic acid) and the polylactic acid (A) is poly (L-lactic acid), since the polylactic acid composition of the present invention forms a stereocomplex, it has a high melting point and is heat resistant. It is preferable because of its excellent properties and mechanical properties.

  The polylactic acid structural unit (I) preferably has a weight average molecular weight of 50,000 to 400,000, more preferably 100,000 to 250,000. If the polylactic acid structural unit (I) has a weight average molecular weight within such a range, it is excellent in practical physical properties such as mechanical properties and heat resistance, and has a suitable melt viscosity and excellent moldability. A polymer (B) can be manufactured.

  The polylactic acid structural unit (I) can use a small amount of chain extender for the purpose of increasing its molecular weight. Examples of the chain extender include diisocyanate compounds such as hexamethylene diisocyanate and toluene diisocyanate, and epoxy compounds. Etc. can be used.

  The polylactic acid structural unit (I) is maleic anhydride, pyromellitic anhydride, trimellitic anhydride for the purpose of improving the compatibility between the polylactic acid copolymer (B) and the filler (C) described later. It may be modified with an acid anhydride. The modification ratio with an acid anhydride is preferably 0.01 to 10% by weight, more preferably 0.05 to 5% by weight, based on the polylactic acid structural unit (I). Particularly preferred is ˜3 wt%. By modifying only in such a range, a carboxyl group having an affinity with the filler (C) described later can be imparted to the polylactic acid copolymer (B), whereby the filler (C) described later is added to the poly (lactic acid) copolymer. A specific amount can be dispersed in the matrix formed by the lactic acid copolymer (B). Examples of the modification method include various methods, and a reactive processing method using an extruder is usually used.

  The polyester structural unit (II) is made of polyester (II ') obtained by reacting a dicarboxylic acid essentially containing dimer acid and a diol.

  Polyester (II ') is obtained by reacting a dicarboxylic acid essentially containing dimer acid and a diol. As such diols, those having 2 to 40 carbon atoms can be used, for example, ethylene glycol, propylene glycol, 1.3-propanediol, 2-methyl 1,3-propanediol, 1,3-butanediol. 1,4-butanediol, 3-methyl 1,5-propanediol, 1,6-hexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, neopentyl glycol, diethylene glycol, triethylene glycol, Examples thereof include dimer diol, polyethylene glycol, polypropylene glycol, block copolymer of polyethylene glycol and polypropylene glycol, polytetramethylene glycol, and the like. These can be used alone or in combination of two or more.

  As the diol, 30% by weight or more of the diol to be used is preferably a diol having a side chain such as propylene glycol or neopentyl glycol, more preferably 50% by weight or more, and further preferably 70% by weight or more. By using the diol having a side chain in such a range, the polylactic acid copolymer (B) can easily form a matrix, and a polylactic acid composition having excellent impact resistance can be obtained.

  As the dicarboxylic acid, it is necessary to use dimer acid. Dimer acid can form a microphase-separated structure in which the polylactic acid copolymer (B) forms a matrix even when the amount used is small, and a polylactic acid composition having excellent impact resistance can be obtained. it can. The dimer acid is a dicarboxylic acid having 30 or more carbon atoms and has a plurality of long side chains, so that the exclusive volume is larger than that of other dicarboxylic acids, and it is easy to form a matrix. This is because it is far from lactic acid and is almost incompatible.

  The dimer acid may be used in combination with another dicarboxylic acid having 2 to 42 carbon atoms within the range of achieving the object of the present invention, such as succinic acid, adipic acid, suberic acid, sebacic acid, azelaic acid, Examples include decanedioic acid, dodecanedioic acid, terephthalic acid, and isophthalic acid, and these can be used alone or in combination of two or more.

  The amount of the dimer acid used in the dicarboxylic acid is such that the polylactic acid copolymer (B), which is one of the characteristics of the present invention, is used from the viewpoint of the glass transition temperature of the polyester (II ′). Since the matrix can be formed even if the amount is smaller than that of lactic acid (A), the amount of dimer acid used is preferably as large as possible, preferably 10% by weight or more, more preferably 30% by weight, and 50% by weight. % Is more preferable.

  In order to make the polyester structural unit (II) having a more branched chain and a high molecular weight, the polyester (II ′) is a trivalent or higher polyvalent ol or carboxylic acid such as glycerin, pentaerythritol, trimellitic acid, An acid anhydride such as pyromellitic anhydride and an isocyanate such as hexamethylene diisocyanate can be used in a small amount within the range of achieving the effects of the present invention.

  As the dicarboxylic acid, it is necessary to use dimer acid, but the glass transition temperature (hereinafter abbreviated as Tg) of the polyester (II ′) obtained thereby can be reduced to 0 ° C. or less, and it is room temperature. However, a polylactic acid composition having excellent impact resistance and flexibility can be produced. In addition, Tg said by this invention is measured with the temperature increase rate of 10 degree-C / min using the differential scanning calorimeter (DSC).

  In order for the polylactic acid composition of the present invention to exhibit impact resistance even at a low temperature, the Tg of the polyester (II ′) constituting the polyester structural unit (II) is −10 ° C. or lower. Preferably, it is −20 ° C. or lower, more preferably −30 ° C. or lower, and particularly preferably −40 ° C. or lower. The lower limit of Tg is not particularly limited, but is −70 ° C. in consideration of the current polyester.

  The polylactic acid copolymer (B) having the polyester structural unit (II) composed of the polyester (II ′) has a crystallization temperature (hereinafter abbreviated as Tc) of the polylactic acid composition of the present invention. The temperature of the mold at the time of molding can be set lower than before. Moreover, even if the temperature of the metal mold | die at the time of shaping | molding is comparable as the past (120 degreeC), the crystallization speed can be accelerated | stimulated more than before and it can crystallize in a short time.

  The weight average molecular weight of the polyester (II ′) is preferably in the range of 20000 to 250,000, more preferably in the range of 30000 to 250,000, and still more preferably in the range of 50000 to 250,000. . By adjusting the weight average molecular weight within such a range, bleeding out from the polylactic acid copolymer (B) can be suppressed, and a polylactic acid composition having excellent impact resistance can be obtained.

  When the polyester (II ′) has a σ / ρ value of 8.54 or more and less than 9.20, the lactic acid copolymer (B) can easily form a matrix, and the effect of imparting impact resistance is increased. 8.60 or more, more preferably 8.70 or more.

  The σ / ρ value referred to in the present invention is a Hoy calculation formula (D.R.Paul, Seamall Newman, “Polymer Blend”, Volume 1, Academic Press, pp. 46-47 (1978) (DR Paul and Seymour Newman, POLYMER BLENDS, vol 1, ACADEMI PRESS, p.46-47 (1978)) This is the value obtained by substituting the substituent constant obtained by Hoy as a numerical value per polymer repeating unit. This is a value calculated by dividing this by the molecular weight per repeating unit, and is represented by σ / ρ = ΣFi / M (where Fi is a substituent constant and M is the molar molecular weight per repeating unit). Examples of base constants are shown.

As an example, a specific calculation method for an aliphatic polyester obtained by polycondensation of ethylene glycol and succinic acid will be described. The aliphatic polyester is represented by — (CH ₂ —CH ₂ —COO—CH ₂ —CH _2). -COO) - represented four substituents from having a repeating unit - (CH ₂₎ - and, for that would have two substituents -COO,

ΣFi = (131.5 × 4 + 326.58 × 2) = 1179.16
It becomes. On the other hand, since the molar molecular weight (M) per repeating unit is 144.13, a value of σ / ρ = 1179.16 / 144.13 = 8.2 is obtained. Some examples are shown in the right column of Table 1.

EG: Abbreviation of ethylene glycol, SuA: Abbreviation of succinic acid, DA: Abbreviation of dimer acid, PLA: Abbreviation of polylactic acid.

  Therefore, the more the polylactic acid copolymer (B) having a σ / ρ value far away from the polylactic acid (A) that is the domain in the polylactic acid composition of the present invention, the more compatible with the polylactic acid (A). Therefore, the polylactic acid copolymer (B) can form a matrix in a smaller amount, and can improve impact resistance.

  The polyester (II ′) uses, for example, the diol and dicarboxylic acid in a molar ratio of 1: 1 to 1.5: 1, and is in a range of 130 ° C. to 240 ° C. for 1 hour in a nitrogen atmosphere. The mixture is stirred while gradually raising the temperature at a rate of 5 to 20 ° C., reacted for 4 to 12 hours while distilling off the generated water, and then the transesterification catalyst and the antioxidant are added to gradually increase the degree of vacuum. However, excess diol is distilled off, and finally, the reaction is carried out at 200 to 250 ° C. for 4 to 24 hours under reduced pressure at 0.5 kPa or less, and a catalyst deactivator is added after completion of the reaction. At this time, polyester (II ′) may be produced in the presence of a filler (C) described later, whereby the filler (C) is mainly dispersed in the matrix formed by the polylactic acid copolymer (B). Can be made.

  Examples of the transesterification reaction catalyst include alkoxides such as Sn, Ti, Zr, Zn, Ge, Ni, Co, Fe, Al, Mn, and Hf, acetates, oxides, and chlorides. Specific examples include titanium tetrapropoxide, titanium tetrabutoxide, titanium bisacetylacetonate, aluminum acetylacetonate, zirconium tetrachloride, zirconium tetrachloride 2THF complex, hafnium tetrachloride, hafnium tetrachloride, 2THF complex. Further, it is desirable to remove these catalysts after completion of the reaction or to deactivate them with a catalyst deactivator.

  As the catalyst deactivator, a chelating agent and / or an acidic phosphate ester is particularly preferable. Although it does not specifically limit as a chelating agent, For example, ethylenediaminetetraacetic acid, ethylenediaminetetraacetic acid disodium, oxalic acid, phosphoric acid, pyrophosphoric acid, alizarin, acetylacetone, diethylenetriaminepentaacetic acid, triethylenetetramine hexaacetic acid, catechol, 4- t-butylcatechol, L (+)-tartaric acid, DL-tartaric acid, glycine, chromotropic acid, benzoylacetone, citric acid, gallic acid, dimercaptopropanol, triethanolamine, cyclohexanediaminetetraacetic acid, ditoluoyltartaric acid, dibenzoyltartaric acid Can be mentioned.

  The acidic phosphate ester forms a complex with the metal ion of the catalyst contained in the hydroxycarboxylic acid polyester resin, loses the catalytic activity, and exhibits a polymer chain cleavage inhibiting effect. Examples thereof include phosphoric acid esters, phosphonic acid esters, alkylphosphonic acid, and mixtures thereof, and examples thereof include 2-ethylhexane phosphate. The above-mentioned acidic phosphoric acid esters are excellent in workability because of good solubility in organic solvents, excellent in reactivity with lactic acid-based polyester resins, and exhibit excellent effects in deactivating the polymerization catalyst.

  The polylactic acid copolymer (B) is obtained, for example, by (1) a method of reacting the lactide (I ′) with the polyester (II ′) in the presence of a polymerization catalyst, or (2) direct polycondensation or lactide of lactic acid. A method of melt-mixing the polylactic acid (I ″) obtained by the ring-opening polymerization of the above and the polyester (II ′), followed by dehydration and polycondensation under reduced pressure in the presence of an esterification or transesterification catalyst, (3) Examples thereof include a method in which the polylactic acid (I ″) and the polyester (II ′) are subjected to azeotropic dehydration polycondensation, that is, direct polycondensation reaction under reduced pressure by adding a transesterification catalyst in the presence of a high-boiling solvent. At this time, polyester (II ′) may be produced in the presence of a filler (C) described later, whereby the filler (C) is mainly dispersed in the matrix formed by the polylactic acid copolymer (B). Can be made.

  (1) The method of copolymerizing lactide (I ′) and polyester (II ′) is carried out by mixing lactide (I ′) and polyester (II ′) at 100 ° C. to 220 ° C. to obtain liquid lactide (I ′ The polyester (II ′) is dissolved in the reaction catalyst, and then the polymerization catalyst (for example, tin octoate) is converted into the lactide (I ′) and the polyester (II ′) at 140 to 220 ° C. in an inert gas atmosphere such as nitrogen or argon. This is a method for producing a polylactic acid copolymer (B) by adding 50 to 1000 ppm for polymerization with respect to the total amount. At this time, 1 to 30 parts by weight of a non-reactive solvent such as toluene may be used with respect to the total weight of the lactide (I ′) and the polyester (II ′) as necessary.

  The same polymerization catalyst as that which can be used in the production of the polyester (II ′) can be used. The reaction temperature is preferably 220 ° C. or less, more preferably 200 ° C. or less, and still more preferably 190 ° C. or less from the viewpoint of preventing the coloring and decomposition of lactide (I ′). Since it is not preferable that moisture is present in the reaction system, it is preferable that the polyester (II ') is sufficiently dried.

  (2) The method of copolymerizing polylactic acid (I ") and polyester (II ') involves polycondensation of polylactic acid (I") and polyester (II'), followed by vacuum polycondensation reaction in the presence of a catalyst. This is a method for producing a polylactic acid copolymer (B). In the polyester (II ′), it is preferable to remove the catalyst used in producing the polyester (II ′) or inactivate with a catalyst deactivator before melt-mixing with the polylactic acid (I ″). As a result, the remaining active catalyst in polyester (II ') acts as a transesterification catalyst for polylactic acid, thereby excessively cleaving the polylactic acid molecular chain, greatly reducing the molecular weight of polylactic acid (I'), and polycondensation reaction The polylactic acid copolymer (B) obtained after completion can be prevented from lowering the molecular weight more than necessary, and the polymerization temperature is preferably 170 to 220 ° C., more preferably 180 to 210 ° C. The degree of vacuum is high vacuum. The more the polymerization proceeds, the more preferable, 2 kPa or less is preferable, 1 kPa or less is more preferable, 0.5 kPa or less is more preferable, and 0.1 kPa or less is particularly preferable.

  As the polymerization catalyst, the same catalysts as those described as being usable when the polyester (II ') is produced can be used. Among them, tetraisopropyl titanate, tetrabutoxy titanium, titanium oxyacetylacetonate, iron (III) acetylacetonate, aluminum acetylacetonate, zirconium tetrachloride, zirconium tetrachloride, 2THF complex, hafnium chloride, hafnium chloride, hafnium chloride-2THF complex Is preferable because aluminum acetylacetonate, zirconium tetrachloride, zirconium tetrachloride, 2THF complex, hafnium chloride, hafnium chloride, 4THF complex are less colored because the resulting polymer is less colored. The amount of the polymerization catalyst used is preferably 50 to 500 ppm of the total amount of polylactic acid (I ′) and polyester (II ′).

  (3) A method of adding an ester exchange catalyst in the coexistence of polylactic acid (I ″), polyester (II ′) and a high-boiling solvent and subjecting it to azeotropic dehydration polycondensation, that is, direct polycondensation reaction under reduced pressure will be described. Can produce a polylactic acid copolymer (B) by azeotropic dehydration using a high boiling point solvent such as xylene, anisole, diphenyl ether, etc., and the azeotropic solvent is dried with molecular sieves filled It is dehydrated and dried in the tower and returned to the reaction system again, but the other conditions can be carried out under the same conditions as in (2), but it is necessary to finally remove the solvent compared to (2). The production method is preferably (1) or (2).

  The polylactic acid copolymer (B) may be further improved in storage stability by extracting the polymerization catalyst with a solvent after the polymerization is completed, or by deactivating the polymerization catalyst with the catalyst deactivator described above. Can do.

  It is important that the polylactic acid copolymer (B) thus obtained is a block copolymer. When this is a random copolymer, there is no polylactic acid structural unit (I) derived from lactide (I ′) or polylactic acid (I ″) which is a compatible component with the polylactic acid (A). The mechanism for suppressing interfacial peeling by improving the adhesion at the interface between the lactic acid copolymer (B) and polylactic acid (A) does not work, causes bleed-out, and also negatively improves impact resistance. On the other hand, since there is no polyester block derived from the polyester (II ′), sufficient impact resistance cannot be imparted.

  The polylactic acid copolymer (B) preferably has a weight average molecular weight of 20000 to 250,000, more preferably in the range of 30000 to 250,000, and still more preferably in the range of 50000 to 200000. By adjusting to such a range, excellent impact resistance can be imparted to the polylactic acid (A), and a polylactic acid copolymer (B) excellent in dispersibility in the polylactic acid (A) can be obtained.

  The average chain length of the polylactic acid structural unit (I) in the polylactic acid copolymer (B) is preferably as long as possible. However, in view of the production method thereof, the lactic acid hydroxyl group H and the carboxyl group OH are substantially. In the case where the lactic acid residue is 1 unit, it is preferably 5 to 3000 units, more preferably 10 to 2000 units, still more preferably 50 to 1000 units, and still more preferably 100 to 1000 units. It is. By producing such a range, the polylactic acid structural unit (I) becomes more compatible with the polylactic acid (A), and the interface between the polylactic acid copolymer (B) and the polylactic acid (A) It is possible to suppress interfacial delamination by improving adhesion and to further prevent bleed out, and to maintain an appropriate viscosity. Therefore, polylactic acid (A) is uniformly dispersed in lactic acid copolymer (B). be able to. In order to convert the above-mentioned unit into a number average molecular weight, the molecular weight of one unit of lactic acid residue is (72) × the number of units. For example, 10 units has a number average molecular weight of 720.

  The weight ratio of the polylactic acid structural unit (I) and the polyester structural unit (II) in the polylactic acid copolymer (B) gives the impact resistance to the polylactic acid copolymer (B). The copolymerization is preferably carried out at least in the range of polylactic acid structural unit (I): polyester structural unit (II) = 10: 90 to 90:10, preferably 25:75 to 70:30. Is more preferably 30:70 to 60:40, and particularly preferably 40:60 to 60:40. When it is desired to impart more excellent impact resistance, it is preferable to increase the proportion of the polyester structural unit (II).

  Next, the filler (C) used in the present invention will be described.

  The filler (C) is used for the purpose of improving the mechanical strength of the polylactic acid composition such as impact resistance, heat resistance, and flexural modulus, but is smaller than conventionally known fillers. It is necessary to disperse a specific amount of a material having a specific average particle diameter in the matrix formed by the polylactic acid copolymer (B).

  Polylactic acid is usually very slow to crystallize, and even if it is molded with a mold heated to 70 to 130 ° C., it takes a long time to crystallize sufficiently. When the temperature of the mold is cooled to room temperature or lower, the resulting molded product is amorphous. When filler (C) is used in the polylactic acid composition, the filler (C) acts as a crystallization nucleating agent, so that the crystallization speed is increased, and molding is performed with a mold heated at a crystallization temperature (70 to 130 ° C.). In this case, the polylactic acid composition is sufficiently crystallized, and a molded product can be produced in a short time within 2 minutes. As a result, the heat resistance, impact resistance, and flexural modulus of the molded product obtained can be improved.

  Examples of the filler (C) include silica, diatomaceous earth, alumina, titanium oxide, iron oxide, zinc oxide, magnesium oxide, antimony oxide, barium ferrite, strontium ferrite, beryllium oxide, pumice, pumice balloon, alumina fiber, aluminum hydroxide , Magnesium hydroxide, basic magnesium carbonate, calcium carbonate, magnesium carbonate, dolomite, dosonite, calcium sulfate, barium sulfate, ammonium sulfate, calcium sulfite, talc, clay, mica, asbestos, glass fiber, glass balloon, glass beads, silicic acid Calcium, layered silicate, carbon black, graphite, carbon fiber, fullerene, carbon nanotube, calcium phosphate, boron nitride, zinc borate, barium metaborate, calcium borate Um, inorganic filler may be mentioned sodium borate, it can be used by mixing two or more of these. In addition, aggregation in the polylactic acid (A) and the polylactic acid copolymer (B) is prevented, and in particular, fatty acids, aminosilanes, vinylsilanes, etc. so as to be easily dispersed mainly in the matrix composed of the polylactic acid copolymer (B). It is preferable to modify the filler surface.

  The average particle diameter of the filler (C) is preferably uniform, and in the present invention, it is necessary that both are in the range of 0.05 to 3 μm. When the average particle diameter is less than 0.05 μm, the impact resistance is not improved. When the average particle diameter exceeds 3 μm, the surface energy of the filler (C) is reduced depending on the type of filler, and the polylactic acid (A) In addition, the affinity and dispersibility with the polylactic acid copolymer (B) are lowered, and impact resistance, heat resistance, rigidity, and the like are lowered. The average particle size of the filler (C) is preferably 0.1 to 2 μm, and more preferably 0.1 to 1 μm. In addition, the average particle diameter of the filler (C) as used in the field of this invention is an average value of the particle size distribution obtained by measuring using a laser diffraction / scattering type particle size distribution measuring apparatus.

  Among the fillers (C), talc, calcium carbonate, and layered silicate are preferable because they can particularly improve mechanical strength such as impact resistance, heat resistance, and flexural modulus.

Talc is an inorganic powder obtained by finely pulverizing an ore called talc, and its chemical name is hydrous magnesium silicate [Mg ₃ Si ₄ O ₁₀ (OH) ₂ ], about 60 wt% SiO ₂ and 30 wt% MgO crystals. The main component is 4.8% by weight of water. The average particle diameter of talc is preferably 0.1 to 2 μm, and more preferably 0.1 to 1 μm. By using talc in such a range, the impact resistance, heat resistance, bending elastic modulus, and surface smoothness of the polylactic acid composition of the present invention can be further improved. The amount of talc used is preferably 3 to 30% by weight, more preferably 5 to 25% by weight, and still more preferably 10 to 25% by weight based on the polylactic acid composition.

Calcium carbonate is mainly composed of CaCO ₃ , and its average particle size is preferably 0.1 to 2 μm, more preferably 0.1 to 1 μm. By adjusting to such a range, the impact resistance, heat resistance, bending elastic modulus, and surface smoothness of the polylactic acid composition can be improved. The amount of calcium carbonate used is the same as talc.

  The layered silicate has a 2: 1 type structure in which, for example, a silicic acid tetrahedral sheet overlaps an octahedral sheet containing elements such as aluminum, magnesium, and lithium to form a single plate crystal layer. It is preferable to have an exchangeable cation having a cation exchange capacity of 0.2 to 3 meq / g between the plate-like crystal layers. The plate-like crystal layer preferably has an average particle size of 0.05 to 0.5 μm. The amount of layered silicate used is preferably 3 to 30% by weight of the polylactic acid composition. Compared with other fillers, the addition of a small amount of the same amount of heat resistance and impact resistance is achieved, and transparency is also improved. 3 to 20% by weight is more preferable, and 5 to 15% by weight is still more preferable.

  As the layered silicate, those subjected to organic cation treatment with a primary or tertiary amine and salts thereof, a quaternary ammonium salt, an organic phosphonium salt or the like in advance are preferable. In the organic cation treatment, the exchangeable cation of the layered silicate is ion-exchanged with the organic cation, thereby increasing the interlayer distance of the layered silicate, and improving the dispersibility of the layered silicate by delamination or intercalation of the polymer. Since it can be improved, heat resistance, impact resistance, flexural modulus and the like can be improved with a smaller amount, which is preferable.

  Examples of layered silicates include, for example, smectite clay minerals such as montmorillonite, beidellite, nontronite, saponite, hectorite, and soconite, various clay minerals such as vermiculite, halloysite, kanemite, kenyanite, zirconium phosphate, and titanium phosphate, Li type Examples thereof include swellable mica such as fluorine teniolite, Na-type fluorine teniolite, Na-type tetrasilicon fluorine mica, and Li-type tetrasilicon fluorine mica, and may be natural or synthesized. Among these, smectite clay minerals such as montmorillonite and hectorite, and swelling synthetic mica such as Na-type tetrasilicon fluorine mica and Li-type fluorine teniolite are preferable. Furthermore, epoxylane, aminosilane compounds, etc. may be used as a compatibilizing agent between the layered silicate and the resin.

  When the amount of the layered silicate used is about 5 to 10% by weight and used when the polyester (II ′) is produced, the layered silicate is finely dispersed during the polymerization of the polyester (II ′). The resulting polylactic acid composition is less likely to lose transparency. The obtained polylactic acid composition preferably has a 200 μm-thick press film having a haze value of 35% or less, more preferably 1 to 30%, still more preferably 1 to 25%. It is particularly preferred that it is ˜20%.

  The filler (C) can impart gas barrier properties to the polylactic acid composition of the present invention. The gas barrier property referred to here is a gas barrier property such as oxygen, nitrogen, carbon dioxide, water vapor, etc., and its permeability can be reduced to about 1/2 to 1/5 when the filler (C) is not used. This is manifested by a “circular path theory” effect in which the finely dispersed layered silicate blocks a gas molecule permeation path, and the gas molecule bypasses the gas molecule and attempts to permeate it to increase the distance to permeate.

  Although the usage-amount of a filler (C) changes a little with the kind of filler, it needs to be the range of 5-30 weight%. 5-25 weight% is more preferable and 10-25 weight% is still more preferable. If it is less than 5% by weight, the impact resistance, heat resistance and mechanical strength are hardly improved. Conversely, if it exceeds 30% by weight, the impact resistance and mechanical strength are not changed or lowered.

  The filler (C) needs to be dispersed in a matrix formed by the polylactic acid copolymer (B). Usually, since the filler (C) is almost uniformly dispersed in the polylactic acid composition, the ratio of the filler present in the matrix is almost the same as the ratio of the matrix present in the polylactic acid composition. In this invention, the weight ratio of the said filler which exists in the said matrix with respect to 100 weight part of the said filler (C) is the said with respect to a total of 100 weight part of the said polylactic acid (A) and the said polylactic acid copolymer (B). It is necessary to make it 5 to 80% by weight higher than the weight ratio of the polylactic acid copolymer (B), and when it is less than 5% by weight, the impact resistance is hardly improved. On the other hand, if it exceeds 80% by weight, the amount of filler (C) dispersed in the polylactic acid (A) domain decreases, so that the heat resistance is not improved. In view of these, it is preferably 10 to 60% by weight, more preferably 10 to 50% by weight, and more preferably 10 to 40% by weight. Thereby, heat resistance and impact resistance can be further improved.

  Next, the polylactic acid composition of the present invention will be described.

  The polylactic acid composition contains the polylactic acid (A), the polylactic acid copolymer (B), and the filler (C), and the polylactic acid (A) is contained in a matrix made of the polylactic acid copolymer (B). ) Is a microphase separation structure in which domains are formed, and the filler (C) needs to be present in the matrix. When the polylactic acid copolymer (B) forms a matrix, a large impact resistance can be exhibited. Examples of the microphase-separated structure include a structure in which a spherical or rod-like domain made of polylactic acid (A) and a matrix made of polylactic acid copolymer (B) form a continuous phase in a canal shape, In some cases, lactic acid (A) may have a spherical and rod-like distribution, which is preferable because mechanical strength such as impact resistance, heat resistance, and flexural modulus is improved and the balance thereof is excellent. The average particle size of the polylactic acid (A) is preferably 0.10 to 5 μm, more preferably 0.2 to 5 μm, and the particle size of 0.3 to 2 μm is most preferable because the impact resistance is maximized. In addition, the average particle diameter said by this invention means the average value of the length of the long axis of a island phase, and a short axis.

  The weight ratio of polylactic acid (A): polylactic acid copolymer (B) is preferably 80:20 to 40:60, more preferably 75:25 to 40:60, still more preferably 70:30 to 50:50. It is. By mixing at such a weight ratio, a microphase-separated structure having a domain made of polylactic acid (A) can be formed in a matrix made of polylactic acid copolymer (B), and the polylactic acid composition has excellent impact resistance and the like Can be obtained.

  In order to efficiently disperse the filler (C) in the lactic acid copolymer (B) as a matrix, (4) a process of producing the polyester (II ′) constituting the polyester structural unit (II), (5) It is preferable to use the filler (C) when the polyester (II ′) is reacted with lactide (I ′) or polylactic acid (I ″) to produce the polylactic acid copolymer (B). It is preferable to use the filler (C) in the process of producing a fine dispersion in the matrix more efficiently than when the polylactic acid (A), the lactic acid copolymer (B) and the filler (C) are blended simultaneously. The filler (C) is used in a smaller amount than before, and the same excellent heat resistance and impact resistance can be imparted.

  The filler (C) may be used again when the polylactic acid copolymer (B) and the polylactic acid (A) are melt blended. In the case of melt blending, it is difficult to disperse the filler (C) uniformly and at a nano level in the polylactic acid composition. Therefore, it is necessary to use a screw with high kneading ability or to increase the rotation speed if it is a twin screw extruder. There is.

  In addition, a plasticizer can be used in the polylactic acid composition of the present invention, such as dioctyl adipate (DOA), acetyl tributyl acetyltributyl citrate (ATBC), dioctyl sebacate (DOS), trimellitic acid plastic Agents, esters such as adipic acid-based polyester, or polyester plasticizers.

  By using such a plasticizer in combination, the affinity of the interface between the polylactic acid (A) and the polylactic acid copolymer (B) can be improved, and the tensile elongation of the polylactic acid composition can be improved. .

  The weight average molecular weight of the plasticizer is preferably 30000 or less, more preferably 10000 or less, and particularly preferably 3000 or less, since those having a low molecular weight can improve the tensile elongation with a smaller amount. . However, if a low molecular weight plasticizer is used, bleed-out resistance or heat resistance may be significantly reduced, so the amount used is preferably 0.5 to 20% by weight based on the polylactic acid composition, It is more preferably 1 to 10% by weight, and further preferably 2 to 10% by weight.

  In the polylactic acid composition of the present invention, an organic filler such as wood powder, kenaf, bamboo fiber can be used, and heat resistance, impact resistance, and mechanical strength can be improved. The amount of the organic filler used is preferably 1 to 30% by weight based on the polylactic acid composition.

  The polylactic acid composition of the present invention includes antioxidants such as 2,6-di-t-butyl-4-methylphenol (BHT) and butyl hydroxyanisole (BHA), salicylic acid derivatives, benzophenone series, benzotriazole The thermal stability at the time of polymerization or molding can be improved by using a UV absorber such as a phosphor and a stabilizer such as phosphate ester, isocyanate, carbodiimide, carbodilite. The addition amount of the stabilizer is not particularly limited as long as it does not impair the effects of the present invention, but it is preferably used in an amount of 0.01 to 10% by weight based on the polylactic acid composition.

  The polylactic acid composition of the present invention includes metal soaps such as zinc stearate, magnesium stearate, calcium stearate, mineral oil, liquid paraffin, silicon oil, ethylene bis stearic acid amide, montanic acid wax, calcium montanic acid salt, A lubricant (or mold release agent) such as oxidized polyethylene can be used, and the mold release property from the mold during molding can be improved and the deformation of the molded product can be prevented.

  In the polylactic acid composition of the present invention, a flame retardant such as phosphorus, bromine, silicone, aluminum hydroxide, and magnesium hydroxide can be used. Can be used as In the polylactic acid composition of the present invention, a nonionic surfactant such as glycerin fatty acid ester and sucrose fatty acid ester, an ionic surfactant such as alkyl sulfonate, and a colorant such as titanium oxide and carbon black are used. be able to.

  In the polylactic acid composition of the present invention, inorganic foaming agents such as sodium bicarbonate and ammonium bicarbonate, organic foaming agents such as azodicarbonamide, azobisisobutyronitrile and sulfonyl hydrazide can be used. Alternatively, a foaming agent such as pentane, butane, or freon can be impregnated into the polymer of the present invention in advance, or a foamed product can be obtained by directly supplying it into the extruder during the extrusion process. Also, lamination with paper, aluminum foil or other degradable polymer film is possible by extrusion lamination, dry lamination or coextrusion.

  Next, the molded product of the present invention will be described.

  The molded product of the present invention is obtained by molding the polylactic acid composition, and is useful, for example, as a packaging material, agricultural material, fishery material, lamination product for paper, foamed resin material, and the like. More specifically, automobile parts including automobile interior parts such as bumpers, car bodies, dashboards, and instrument panels, casings, trays, cups for electronic and electrical equipment such as TVs, refrigerators, washing machines, telephones, mobile phones, and personal computers. , Dish, blister, blow molded product (shampoo bottle, cosmetic bottle, beverage bottle, oil container), injection molded product (golf tee, cotton swab core, candy stick, brush, toothbrush, helmet, syringe, dish, cup, Combs, razor handles, tape cassettes and cases, disposable spoons and forks, stationery such as ballpoint pens, etc.).

  Packaging materials include sheet materials, film materials, and more specifically shrink film, vapor deposition film, wrap film, food packaging, other general packaging, garbage bags, plastic bags, general standard bags, heavy bags, etc. Examples include bags, agricultural multi-films, germination films, curing films, seedling pots, and the like.

  Lamination products for paper, such as trays, cups, dishes, megaphones, etc., as well as binding tapes (binding bands), prepaid cards, balloons, pantyhose, hair caps, sponges, cellophane tapes, umbrellas, duvets, plastics Gloves, hair caps, ropes, tubes, foam trays, foam cushioning materials, cushioning materials, packing materials, cigarette filters and the like. Other examples include medical materials and fiber materials.

  Examples of the molding method of the molded product of the present invention include an injection molding method, a blow molding method, a vacuum molding method, a pressure forming method, and a compression molding method.

  The injection molding method is a method for producing a molded product by injecting a polylactic acid composition into a mold and heating it, and a mold such as a container can be produced using a normal injection molding machine. At that time, it is preferable that the mold can be heated to a temperature of Tg or higher.

  The blow molding method is a method for producing a molded product by expanding a polylactic acid composition molded into a tube shape in a mold, and easily molding a single layer or a multilayer bottle by using an existing molding machine. be able to.

  When molding by the molding method, impact resistance and heat resistance can be further improved by annealing.

  Annealing is, for example, a method in which the temperature of the mold is set in the range of the crystallization start temperature to the end temperature when DSC is lowered, and the polylactic acid composition of the present invention is crystallized in the mold. A molded product having excellent impact strength can be produced. Mold temperature is 70-130 degreeC, 80-120 degreeC is preferable, 80-110 degreeC is more preferable, 90-110 degreeC is more preferable. Within such a temperature range, the polylactic acid composition is easily crystallized, and after molding, when the molded product is taken out from the mold, it can be solidified to obtain a molded product with good dimensional accuracy. The crystallization time is from 1 second to 10 minutes, but when practicality such as productivity is considered, this time is preferably as short as possible. Therefore, it is preferably 1 second to 3 minutes, more preferably 1 second to 1 minute. is there.

  Among the molded products, the film can be used for packaging materials such as shrink film and wrap film, and trays, cups, and the like can be produced by further processing the film by vacuum forming or the like. In addition, although the sheet | seat and the film are conventionally used properly by thickness normally, in order to avoid confusion in this invention, it names generically and is set as a film. The thickness of the film of the present invention is not particularly limited, but generally refers to 5 μm to 2 mm.

  Examples of the film forming method include extrusion molding methods such as a T-die cast molding method and an inflation molding method.

  Although the melting temperature in the T-die casting method is not particularly limited, it is usually preferable that the melting temperature is 10 to 60 ° C. higher than the melting point of polylactic acid (A). The melt-extruded film is usually cast so as to have a predetermined thickness, and cooled if necessary. At that time, when the film thickness is thick, a uniform film can be produced by properly using a touch roll and an air knife, and when it is thin, electrostatic pinning.

  The melting temperature in the inflation molding method is the same as that in the T-die casting method, and a film can be easily produced with a molding apparatus equipped with a normal circular die and air ring. At this time, in order to avoid uneven thickness, the die, air ring or winder may be rotated.

  The extruder screw of the extruder used in the molding method usually has an L / D ratio of 20 which is the ratio of the length (L) of the kneading part of the screw and the diameter (D) of the kneading screw. A full flight type of about 50 may be used, and a vent may be provided. The appropriate extrusion temperature varies depending on the molecular weight, composition, and viscosity of the polylactic acid composition to be used, but it is preferably higher than the flow start temperature.

  The obtained film can be stretched uniaxially and biaxially by a tenter method or an inflation method at a temperature not lower than the glass transition temperature and not higher than the melting point. Further, by performing a stretching treatment, molecular orientation can be generated, and physical properties such as impact resistance, rigidity, and transparency can be improved.

  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, longitudinal stretching by a roll method and transverse stretching by a tenter can be mentioned. As the method, the first-axis stretching and the second-axis stretching may be performed sequentially or simultaneously. The draw ratio is preferably 1.3 to 6 times in the longitudinal direction and the transverse direction. If the draw ratio is lower than this, it is difficult to obtain a film having a sufficiently satisfactory strength, and if it is high, the film will be broken during stretching. In addition, when shrinkage | contraction property of a shrink film etc. is requested | required especially at the time of heating, high magnification extending | stretching of 3-6 times etc. to a uniaxial or biaxial direction is preferable.

  The stretching temperature is preferably in the range of glass transition temperature (hereinafter referred to as Tg) to (Tg + 50) ° C. of the polylactic acid composition, and particularly preferably in the range of Tg to (Tg + 30) ° C. By setting the stretching temperature within such a range, the film can be sufficiently stretched, and the strength by stretching can be improved.

  The film can be subjected to heat setting treatment (crystallization treatment) under tension immediately after stretching to promote strain removal or crystallization, and as a result, heat resistance of the film can be improved. The temperature of the heat setting treatment is preferably 70 to 130 ° C, more preferably 70 to 120 ° C, still more preferably 80 ° C to 110 ° C, and particularly preferably 90 to 110 ° C. By heat setting at a temperature in such a range, not only heat resistance but also film physical properties such as tensile elongation can be improved. The heat setting treatment time is usually 1 second to 3 minutes, preferably 1 second to 1 minute, more preferably 1 second to 30 seconds.

  The film can be secondarily processed by a vacuum forming method, a pressure forming method, a vacuum pressure forming method, or the like.

  Among the secondary processing methods for the film, in the case of a vacuum forming method or a vacuum / pressure forming method, a plug assist forming method is preferable. When the film is a stretched film, it is preferable to apply a pressure forming method. Note that heating and cooling of the mold at the time of molding can be performed arbitrarily, and in particular, the heat resistance can be improved by setting the temperature of the mold to be equal to or higher than the crystallization temperature and actively promoting crystallization.

  The film can be produced into a bag using a normal bag making machine such as a horizontal pillow bag making machine, a vertical pillow bag making machine, or a twist back bag making machine.

  Since the polylactic acid composition of the present invention is easily hydrolyzed due to its high hygroscopicity, it is dehumidified and dried beforehand with a vacuum dryer or the like in order to avoid hydrolysis during molding, and the water content in the raw material is 50 ppm or less It is preferable to keep it in the range.

  EXAMPLES Hereinafter, although this invention is demonstrated further more concretely using an Example and a comparative example, this invention is not limited to these Examples at all.

The measurements performed in the examples are as follows.
(Molecular weight measurement)
It measured by the comparison with a polystyrene standard sample with the gel permeation chromatography measuring apparatus (Hereafter, it abbreviates as GPC. HLC-8020 by Tosoh Corporation, column temperature 40 degreeC, tetrahydrofuran solvent).

(Thermal properties measurement)
Using a differential scanning calorimeter (hereinafter abbreviated as DSC; DSC220C manufactured by Seiko Denshi Kogyo Co., Ltd.), a range of −100 to 200 ° C. was measured at a temperature rising rate of 10 ° C./min.

(Vicat softening point temperature)
Using a heat starter manufactured by Toyo Seiki Co., Ltd., a test piece after molding was measured under the conditions of a load of 1 kgf and a temperature increase rate of 50 ° C./hour in accordance with ASTM-D1525.

(Storage elastic modulus (E ′); hereinafter abbreviated as DMA)
Using a Rheometrics RSAII, a film having a thickness of 200 μm × width of 5 mm × length of 35 mm was measured by FILM TEXTURE geometry under conditions of 22.4 mm between chucks, 6.28 rad, −50 to 120 ° C.

(Transparency measurement; hereinafter abbreviated as “haze”)
A 10 cm long × 10 cm wide film was cut into 5 cm long × 5 cm wide and measured with a turbidimeter (ND-1001DP manufactured by Nippon Denshoku Industries Co., Ltd.).

(Izod impact test; hereinafter abbreviated as IZOD)
It was measured by an Izod impact test method (notched) according to JIS K 7110.

(DuPont impact strength test)
Using the DuPont impact strength measurement method of JIS K 5400, the weight of the weight having a constant weight was changed and dropped, and the 50% fracture energy of the obtained film was determined depending on the presence or absence of breakage. The striking portion with the film is made of steel, and is a smooth hemisphere (manufactured by Uesima Seisakusho) with a radius of 6.3 mm.

(Film impact test)
It measured by the method based on ASTMD-3420.

(Tensile test)
It measured according to JIS-K7127 using Shimadzu Tensilon. The test piece was made with a JIS No. 2 dumbbell and a tensile speed of 5 mm / min.

Reference Example 1 (Polyester (PG-DA) synthesis: A-1)
In a 50 L reaction kettle equipped with a full zone blade, a rectifier, and a gas introduction tube, 3.20 kg of propylene glycol (hereinafter abbreviated as PG) and dimer acid (Empol 1061, manufactured by Cognis, abbreviated as DA) are 20. The mixture was charged with 00 kg and stirred with heating while increasing the temperature from 150 ° C. to 15 ° C. per hour under a nitrogen stream. The temperature was raised to 230 ° C. while distilling off the water produced, and after 1 hour, 60 ppm of transesterification catalyst titanium tetrabutoxide was added, and the mixture was stirred for 8 hours after reducing the pressure to 0.1 KPa, and then 2-ethyl as a catalyst deactivator. Hexanoic acid phosphate (AP-8 manufactured by Daihachi Chemical Co., Ltd., hereinafter abbreviated as AP-8) was added at 50 ppm, and weight average molecular weight (Mw) = 45,000 and number average molecular weight (Mn) = 24,000 polyester ( 21.10 kg of A-1) was obtained.

Reference Example 2 (Polyester (16HD-DA / SeA) Synthesis: A-2)
8.15 kg of 1,6-hexanediol (hereinafter abbreviated as 16HD) and 2.15 kg of layered silicate (SAN manufactured by Coop Chemical Co., average particle diameter of 50 nm, hereinafter abbreviated as layer silicate) were charged for 24 hours. After standing, DA was charged at 10.00 kg and sebacic acid (hereinafter abbreviated as SeA) 8.45 kg, and polymerized under the same conditions as in Reference Example 1 to obtain a polyester having a Mw = 36,000 and Mn = 19000 (A -2) was obtained 21.5 kg.

Reference Example 3 (Synthesis of polyester (NPG-DA / AA): A-3)
10.70 kg of neopentyl glycol (hereinafter abbreviated as NPG), 15.00 kg of DA and 9.10 kg of acrylic acid (hereinafter abbreviated as AA) were charged and polymerized under the same conditions as in Reference Example 1, and Mw = 29.00 kg of polyester (A-3) having 74,000 and Mn = 37,000 was obtained.

(Reference Example 4) (Synthesis of polyester (PG-AA): A-4)
A 50 L reactor was charged with 10.80 kg of PG and 18.20 kg of AA, and heated and stirred while increasing the temperature from 150 ° C. to 15 ° C. per hour under a nitrogen stream. While distilling off the generated water, the temperature was raised to 230 ° C., and after 1 hour, 60 ppm of transesterification catalyst titanium tetrabutoxide was added, and the pressure was reduced to 0.1 KPa, followed by stirring for 1 hour, and then catalyst deactivator AP-8 was added. 50 ppm was added, and 25.00 kg of polyester (A-5) having a weight average molecular weight (Mw) = 15,000 and a number average molecular weight (Mn) = 9,000 was obtained.

(Production Example 1) (Synthesis of polylactic acid copolymer B-1)
6.00 kg of polyester (A-1) and 6.00 kg of L-lactide (manufactured by Purac, hereinafter abbreviated as L-LD) were charged in a 25 L reaction kettle, stirred and melted at 200 ° C., and 150 ppm of tin octoate as a catalyst. Was added and polymerized for 3 hours. Thereafter, 120 ppm of ethylenediaminetetraacetic acid (hereinafter abbreviated as EDTA) was added as a catalyst deactivator, and the residual lactide was devolatilized under a reduced pressure of 0.1 kPa for 1 hour to complete the polymerization. Mw = 68,000, Mn = 37, 000, residual lactide = n. d. The polylactic acid copolymer (B-1) was obtained.

(Production Example 2) (Synthesis of polylactic acid copolymer B-2)
4.80 kg of polyester (A-1), 4.80 kg of L-LD, and 2.40 kg of talc (SG-2000 manufactured by Nippon Talc Co., Ltd., average particle diameter of 1 μm, hereinafter abbreviated as talc S) are charged. Polymerization was carried out under the same conditions as in Production Example 1, Mw = 62,000, Mn = 33,000, residual lactide = n. d. Of polylactic acid copolymer (B-2) was obtained.

(Production Example 3) (Synthesis of polylactic acid copolymer B-3)
6.00 kg of polyester (A-1) and 6.00 kg of polylactic acid (Lacia H-400 manufactured by Mitsui Chemicals, hereinafter abbreviated as PLA) were charged, and 150 ppm of titanium tetrabutoxide was used as a catalyst in a nitrogen atmosphere. After the addition, after polymerization for 5 hours at 200 ° C. under reduced pressure of 0.1 kPa, AP-8 was added at 120 ppm, and the residual lactide was devolatilized under reduced pressure of 0.1 kPa for 1 hour to obtain Mw = 11,000, Mn = 59,000. , Residual lactide = n. d. Of polylactic acid copolymer (B-3) was obtained.

(Production Example 4) (Synthesis of polylactic acid copolymer B-4)
8.40 kg of polyester (A-2), 3.24 kg of PLA, 1.32 kg of layered silicate and 0.07 kg of epoxy run were charged and polymerized under the same conditions as in Production Example 3, and Mw = 78,000, Mn = 36,000, residual lactide = n. d. Of polylactic acid copolymer (B-4) was obtained.

(Production Example 5) (Synthesis of polylactic acid copolymer B-5)
7.00 kg of polyester (A-3), 3.00 kg of L-LD, 4 calcium carbonate (Calcium P, manufactured by Kamishima Chemical Industry Co., Ltd., average particle size 0.15 μm, hereinafter abbreviated as charcoal). 50 kg, polymerized under the same conditions as in Production Example 3, Mw = 75,000, Mn = 38,000, residual lactide = n. d. Of the polylactic acid copolymer (B-5) was obtained.

(Comparative Production Example 1) (Synthesis of polylactic acid copolymer HB-1)
4.80 kg of polyester (A-1), 4.80 kg of L-LD, 2.40 kg of talc L (MS manufactured by Nippon Talc Co., Ltd., average particle diameter: 13 μm, hereinafter abbreviated as talc L), Polymerization was carried out under the same conditions as in Production Example 1, Mw = 60,000, Mn = 32,000, residual lactide = n. d. Polylactic acid copolymer (HB-1) was obtained.

(Example 1) (Preparation of polylactic acid composition P-1)
After dry blending 3.00 kg of polylactic acid copolymer (B-1) and 1.80 kg of talc S, it was melt-kneaded at a cylinder temperature of 200 ° C. with a twin screw extruder to obtain master batch pellets in advance. Then, a pellet (P-1) obtained by blending 3.84 kg of this master batch pellet and 5.60 kg of PLA at a cylinder temperature of 200 ° C. using a twin screw extruder was obtained.

(Example 2) (Preparation of polylactic acid composition P-2)
After dry blending 3.00 kg of polylactic acid copolymer (B-2) and 0.84 kg of talc S, it was melt-kneaded at a cylinder temperature of 200 ° C. with a twin screw extruder to obtain master batch pellets in advance. Then, a pellet (P-2) obtained by blending 2.88 kg of this master batch pellet and 4.20 kg of PLA under the same conditions as in Example 1 was obtained.

(Example 3) (Preparation of polylactic acid composition P-3)
After dry blending 3.00 kg of polylactic acid copolymer (B-2) and 0.84 kg of talc S, it was melt-kneaded at a cylinder temperature of 200 ° C. with a twin screw extruder to obtain master batch pellets in advance. In addition, 2.88 kg of this master batch pellet, 4.20 kg of PLA, and 0.3 kg of dioctyl sebacate (hereinafter abbreviated as DOS) were blended under the same conditions as in Example 1 (P- 3) was obtained.

(Example 4) (Preparation of polylactic acid composition P-4)
After dry blending 3.00 kg of polylactic acid copolymer (B-3) and 1.80 kg of talc S, it was melt-kneaded at a cylinder temperature of 200 ° C. with a twin screw extruder to obtain master batch pellets in advance. In addition, 3.84 kg of this master batch pellet, 5.60 kg of PLA, and 0.40 kg of polyester (A-4) were blended at a cylinder temperature of 200 ° C. using a twin-screw extruder (P-4 )

(Example 5) (Preparation of polylactic acid composition P-5)
A pellet (P-5) obtained by blending 8.4 kg of PLA, 4.32 kg of polylactic acid copolymer (B-4), and 0.51 kg of layered silicate under the same conditions as in Example 1 was obtained. It was. FIG. 1 shows a TEM photograph of the pellet (P-5).

(Example 6) (Preparation of polylactic acid composition P-6)
A pellet (P-6) obtained by blending 6.00 kg of PLA, 5.80 kg of polylactic acid copolymer (B-5), and 0.80 kg of charcoal cal under the same conditions as in Example 1 was obtained. It was.

(Comparative Example 1) (Preparation of polylactic acid composition HP-1)
After dry blending 8.40 kg of PLA and 2.16 kg of talc S, the mixture was melt kneaded at a cylinder temperature of 200 ° C. with a twin screw extruder to obtain a master batch pellet in advance, and 5.28 kg of this master batch pellet was obtained. A pellet (HP-1) obtained by blending 1.80 kg of the polylactic acid copolymer (B-1) under the same conditions as in Example 1 was obtained.

(Comparative Example 2) (Preparation of polylactic acid composition HP-2)
After dry blending 3.00 kg of polylactic acid copolymer (HB-1) and 0.84 kg of talc L, it was melt kneaded at a cylinder temperature of 200 ° C. with a twin screw extruder to obtain master batch pellets in advance. Then, 2.88 kg of this master batch pellet and 4.20 kg of PLA were blended under the same conditions as in Example 1 to obtain a pellet (HP-2).

(Comparative Example 3) (Preparation of polylactic acid composition HP-3)
A pellet (HP-3) obtained by blending 7.0 kg of PLA and 3.00 kg of the polylactic acid copolymer (B-1) under the same conditions as in Example 1 was obtained.

(Filler amount evaluation method for polylactic acid composition)
50.0 g of each polylactic acid composition pellet (about 3 mmφ × 4 mm cylinder) obtained in Examples 1 to 6 and Comparative Examples 1 to 3 was placed in 500 ml of acetone, allowed to stand for 24 hours, and then filtered to dissolve the matrix. The domain residue was put in methanol and centrifuged to separate the polylactic acid and the filler. The filler floating material was collected and dried, and its weight was measured. This amount was taken as the content of the filler contained in the matrix, and the results are shown in Tables 5-6. The amount of polylactic acid contained in this amount was 5% by weight or less.

(Polylactic acid composition injection molding method and evaluation method)
Each polylactic acid composition obtained in Examples 1 to 6 and Comparative Examples 1 to 3 was dried under reduced pressure at 100 ° C. for 6 hours, injection-molded with a 1 ounce injection molding machine, and then temperature-controlled at 100 ° C. For 30 seconds to obtain an IZOD test piece. These Vicat softening point temperatures and IZOD impact strength (notched) were measured, and the results are shown in Tables 5-6.

(Deposition method and evaluation method of 200 μm film)
Each polylactic acid composition obtained in Examples 1 to 6 and Comparative Examples 1 to 3 was dried under reduced pressure at 100 ° C. for 6 hours, L / D = 36 50 mm single screw extruder (manufactured by Tanabe Plastics), cylinder temperature. It was melt-kneaded at 220 ° C. and extruded from a die into a sheet having a width of 30 cm and a thickness of 200 μm. For the cooling of the sheet thermally melted at the die outlet, a touch roll was used for Examples 4 to 7, and an air knife was used otherwise. The film was crystallized by heat setting at 100 ° C. for 1 minute. The obtained 200 μm film was measured for DuPont impact value, haze, tensile modulus, tensile elongation and 20 ° C. storage modulus at DMA, and the results are shown in Tables 5-6.

(Method for forming and evaluating biaxially stretched heat set film)
Each of the polylactic acid compositions obtained in Examples 1 to 6 and Comparative Examples 1 to 3 was melt-kneaded at a cylinder temperature of 220 ° C. with a L / D = 36 50 mm single-screw extruder (manufactured by Tanabe Plastics Co.). Extruded into a sheet having a width of 30 cm and a thickness of 100 μm. An air knife was used to cool the sheet melted at the die outlet. Furthermore, after stretching to twice the longitudinal and lateral same ratio by successive stretching at a stretching temperature condition of 70 ° C. and a stretching speed of 10 mm / second, heat setting was performed at 140 ° C. for 50 seconds, and a biaxial stretching heat of 25 μm in thickness. A set film was obtained. About this, the film impact, haze, the tensile elasticity modulus, and the tensile elongation were measured, and the result was shown to Tables 5-6.

(Film bleed-out evaluation method)
Further, the film was left in a constant temperature and humidity chamber PR-2F manufactured by Tabai Espec Co., Ltd. maintained at 35 ° C. and a humidity of 80%. The state of the film was observed every month, and the number of days that bleed-out started was evaluated, but no bleed-out occurred during the evaluation.

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The TEM photograph of P-5 is shown. The black part shows the polylactic acid copolymer (B-4), the white part shows the polylactic acid, the polylactic acid copolymer (B-4) is a canal-like continuous phase matrix, and the polylactic acid (A) is a domain morphology. It has become.

Claims (7)

Polylactic acid (A), polylactic acid structural unit (I), polylactic acid copolymer (B) having polyester structural unit (II) derived from dicarboxylic acid containing dimer acid and diol, and average particles A polylactic acid composition comprising 5 to 30% by weight of a filler (C) having a diameter of 0.05 to 3 μm, wherein the polylactic acid (A) is contained in a matrix formed by the polylactic acid copolymer (B). ) Have a microphase-separated structure forming a domain, and [weight ratio of the filler present in the matrix to 100 parts by weight of the filler (C) -copolymerization of the polylactic acid (A) and the polylactic acid The weight ratio of the polylactic acid copolymer (B) to the total 100 parts by weight of the combined body (B)] is 5 to 80% by weight. [The weight ratio of the filler present in the matrix to 100 parts by weight of the filler (C) -the polylactic acid copolymer with respect to a total of 100 parts by weight of the polylactic acid (A) and the polylactic acid copolymer (B)] 2. The polylactic acid composition according to claim 1, wherein the weight ratio of the polymer (B) is 10 to 60% by weight. The polylactic acid composition according to claim 1 or 2, wherein the filler (C) is talc having an average particle size of 0.1 to 3 µm. The polylactic acid composition according to claim 1 or 2, wherein the filler (C) is calcium carbonate having an average particle size of 0.1 to 2 µm. The polylactic acid composition according to claim 1 or 2, wherein the filler (C) is a layered silicate having an average particle size of 0.05 to 0.5 µm. The polylactic acid composition according to any one of claims 1 to 5, comprising 2 to 10% by weight of a polyester plasticizer. A molded article obtained by using the polylactic acid composition according to any one of claims 1 to 6.

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