JP2008088402A - Polylactic acid-based stretched film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To develop a polylactic acid-based stretched film being biodegradable and excellent in transparency and heat resistance. <P>SOLUTION: This polylactic acid-based stretched film comprises a polylactic acid-based composition containing poly-L-lactic acid and poly-D-lactic acid, and the peak ratio between the peak height (peak 1) of the maximum endothermic peak in the endothermic peak within a temperature range of 150-200°C and the peak height (peak 2) of the maximum endothermic peak in the endothermic peak within a temperature range of 205-240°C in a DSC measurement, namely the ratio of peak 1/ peak 2, is not more than 0.2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a stretched polylactic acid film having biodegradability and excellent transparency and heat resistance.

In order to facilitate the disposal of plastic films, biodegradable films have attracted attention and various films have been developed. The biodegradable film is subject to hydrolysis and biodegradation in soil and water, gradually breaking down and decomposing the film, and finally changing to a harmless degradation product by the action of microorganisms. As such a film, a film formed from an aromatic polyester resin, an aliphatic polyester resin such as polylactic acid or polybutylene succinate, polyvinyl alcohol, cellulose acetate, starch or the like is known.

A biaxially stretched film made of polylactic acid, which is one of such biodegradable resins, has begun to be used as a packaging film because of its excellent transparency, but it is inferior in heat resistance as it is.

On the other hand, as a method for improving the heat resistance of polylactic acid, poly-L-lactic acid (PLLA) and poly-D
-Many methods of blending lactic acid (PDLA) to form a stereo complex have been proposed (for example, Patent Document 1, Patent Document 2, Non-Patent Document 1).
However, even if a composition obtained by simply melt-kneading PLLA and PDLA is formed into a film, a stereocomplex is not easily formed, and the formed film is brittle, although the heat resistance is improved, It is difficult to use as a packaging film.
Japanese Patent Laid-Open No. 9-25400 JP 2000-17164 A Macromolecules, 20, 904 (1987)

An object of this invention is to develop the polylactic acid-type stretched film which has biodegradability, and is excellent in transparency and heat resistance.

The present invention comprises a polylactic acid-based composition containing poly-L-lactic acid and poly-D-lactic acid, and has a peak endothermic peak height (peak 1) in the range of 150 to 200 ° C. in DSC measurement. And a peak ratio (peak 1 / peak 2) between the maximum endothermic peak height (peak 2) of the endothermic peak in the range of 205 to 240 ° C. is 0.2 or less, and is a polylactic acid stretch A film is provided.

The polylactic acid-based stretched film of the present invention can be used up to 180 ° C., while the usable temperature of the conventional polylactic acid biaxially stretched film is up to 140 ° C., and the biodegradability is not impaired and is transparent. Also excellent.

<Poly-L-lactic acid> Poly-L-lactic acid which is one component of the polylactic acid-based composition according to the present invention (
PLLA) is a polymer containing L-lactic acid as a main constituent, preferably 95 mol% or more. A polymer having an L-lactic acid content of less than 95 mol% is poly-D-lactic acid (PDLA) described later.
There is a possibility that the heat resistance of the stretched film obtained by stretching the polylactic acid composition obtained by melting and kneading is inferior.

The molecular weight of PLLA is not particularly limited as long as the polylactic acid-based composition mixed with poly-D-lactic acid described later has formability as a layer such as a film. Usually, the weight average molecular weight (Mw) is 6,000 to 300. Poly-L lactic acid in the range of 10,000, preferably 6,000 to 2,000,000 is suitable. If the weight average molecular weight is less than 6,000, the strength of the resulting stretched film may be inferior. Meanwhile, 3
If it exceeds 00000, the melt viscosity is large and the film processability may be inferior.
<Poly-D-lactic acid>
Poly-D-lactic acid (PDLA) which is one component of the polylactic acid composition layer according to the present invention is D
-A polymer containing lactic acid as a main constituent, preferably 95 mol% or more. A polymer having a D-lactic acid content of less than 95 mol% may be inferior in heat resistance of a stretched film obtained by stretching a polylactic acid-based composition obtained by melt-kneading with the poly-L-lactic acid described above. is there.

The molecular weight of PDLA is not particularly limited as long as the polylactic acid composition mixed with the aforementioned PLLA has formability as a film, but the weight average molecular weight (Mw) is usually 6,000 to 300.
Poly-D lactic acid in the range of 10,000, preferably 6,000 to 2,000,000 is suitable. If the weight average molecular weight is less than 6,000, the strength of the resulting stretched film may be inferior. On the other hand, if it exceeds 3 million, the melt viscosity is large and the film processability may be poor.

In the present invention, PLLA and PDLA contain a small amount of other copolymer components such as polycarboxylic acid or ester thereof, polyhydric alcohol, hydroxycarboxylic acid, lactone, etc. within the range not impairing the object of the present invention. It may be polymerized. Specific examples of the polyvalent carboxylic acid include succinic acid, glutaric acid, adipic acid, pimelic acid, azelaic acid, suberic acid, decanedicarboxylic acid, dodecanedicarboxylic acid, sebacic acid, diglycolic acid, ketopimelic acid, Examples thereof include aliphatic dicarboxylic acids such as malonic acid and methylmalonic acid, and aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid and 2,6-naphthalenedicarboxylic acid.
Specific examples of the polyvalent carboxylic acid ester include dimethyl succinate, diethyl succinate, dimethyl glutarate, diethyl glutarate, dimethyl adipate, diethyl adipate, dimethyl pimelate, dimethyl azelate, and dimethyl suberate. , Diethyl suberate, dimethyl sebacate, diethyl sebacate, dimethyl decanedicarboxylate,
Aliphatic dicarboxylic acid diesters such as dimethyl dodecanedicarboxylate, dimethyl diglycolate, dimethyl ketopimelate, dimethyl malonate and dimethyl methylmalonate, and aromatic dicarboxylic acid diesters such as dimethyl terephthalate and dimethyl isophthalate.
Specific examples of the polyhydric alcohol include ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,3-butanediol, 2-methyl-propanediol, and 1,4-butanediol. , Neopentyl glycol, pentamethylene glycol, hexamethylene glycol, octamethylene glycol, decamethylene glycol, dodecamethylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, diethylene glycol, dipropylene glycol, triethylene glycol , Tetraethylene glycol, pentaethylene glycol, polyethylene glycol having a molecular weight of 1000 or less, and the like.
Specific examples of the hydroxycarboxylic acid include glycolic acid, 2-methyllactic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxy-n-butyric acid, 2-hydroxy-3,3-dimethylbutyric acid, Examples include 2-hydroxy-2-methylbutyric acid, 2-hydroxy-3-methylbutyric acid, hydroxypivalic acid, hydroxyisocaproic acid, and hydroxycaproic acid. Specific examples of lactones include, for example, β-propiolactone,
β-butyrolactone, γ-butyrolactone, β or γ-valerolactone, δ-valerolactone, δ-caprolactone, ε-caprolactone, 4-methylcaprolactone, 3, 5,
Various methylated caprolactones such as 5-trimethylcaprolactone and 3,3,5-trimethylcaprolactone; cyclic monomeric esters of hydroxycarboxylic acids such as β-methyl-δ-valerolactone, enanthlactone and laurolactone; glycolide, L- Examples thereof include cyclic dimer esters of the above hydroxycarboxylic acids such as lactide and D-lactide.
Further, PLLA and PDLA according to the present invention may each contain a small amount of D-lactic acid or L-lactic acid as long as it is within the above range.

<Polylactic acid-based stretched film>
The stretched polylactic acid film of the present invention comprises a polylactic acid-based composition containing the poly-L-lactic acid and poly-D-lactic acid, and has a maximum endothermic peak of 150 to 200 ° C. in the DSC measurement. The peak ratio (Peak 1 / Peak 2) between the peak height (Peak 1) and the peak endotherm peak height (Peak 2) in the range of 205-240 ° C. is 0.2.
Hereinafter, it is a polylactic acid-type stretched film characterized by being 0.1 or less preferably.

In addition to the above characteristics, the polylactic acid-based stretched film of the present invention has an endothermic peak endothermic amount (ΔHm) in the range of 205 to 240 ° C. of 40 J / g or more, more preferably 50 J / g or more. After measuring the endothermic peak, the calorific value (ΔHc) when the temperature falls is 40 J / g
As mentioned above, it has the characteristic of 50 J / g or more more preferably.

In addition to the above properties, the stretched polylactic acid film of the present invention has a 2θ of 1 in the wide-angle X-ray measurement.
The sum of the peak areas around 2 degrees, 21 degrees and 24 degrees (S _SC ) is 20 with respect to the total area.
%, Preferably 25% or more, and the sum (S _PL ) of peak areas in the vicinity of 2θ of 17 ° and 19 ° is 5% or less, preferably 3% or less.
In such wide-angle X-ray measurement, peaks at 2θ of around 17 degrees and 19 degrees are PLLA and P
The peak is based on DLA crystals (P _PL ), and the peaks around 12 degrees, 21 degrees and 24 degrees are peaks based on so-called stereocomplex crystals (P _SC ) in which PLLA and PDLA are co-crystallized. The diffraction peak (2θ) due to wide-angle X-rays in the present invention is an X-ray diffractometer (automatic X-ray diffractometer RINT-2200 or RINT-2500 manufactured by Rigaku Corporation).
) Is the angle (degree) of the diffraction peak measured and detected using Base line of recording paper (strength: 0
cps) and the diffraction angle (2θ) enclosed by the X-ray diffraction intensity curve is 10 to 30 degrees, and the total area (total area) is 100%, and each diffraction peak area based on the crystal is about (S _PL ) Is 1
For the diffraction peaks (2θ) near 7 ° and 19 °, and (S _SC ), the areas of the diffraction peaks (2θ) near 12 °, 21 °, and 24 ° are cut out from the recording paper and the weight is measured. Calculated. Moreover, the broad part resulting from an amorphous part was made into (amorphous part). When measuring (S _PL ) and (S _SC ), the diffraction curve associated with the amorphous portion was used as a baseline and the portion above it was measured. In addition, when there exists air scattering, it is contained in the broad part resulting from an amorphous part.

The heat melting property of the polylactic acid-based stretched film in the present invention is a DSC (Differential Scanning Calorimeter), using Q100 manufactured by TA Instruments Inc., accurately weighing about 5 mg of a sample,
According to JIS K 7121 and JIS K 7122, nitrogen gas inflow: 50 ml /
Minutes, the heating rate was raised from 0 ° C. to 250 ° C. at a rate of 10 ° C./min to obtain a DSC curve at the time of temperature rise, and from the obtained DSC curve, the melting point (Tm) of the stretched film, Endothermic amount of endothermic peak in the range of 240 ° C. (ΔHm), maximum endothermic peak height in the range of 150 to 200 ° C. (peak 1) and maximum endothermic peak in the range of 205 to 240 ° C. Obtain the peak ratio (peak 1 / peak 2) of the endothermic peak height (peak 2) and maintain it at 250 ° C. for 10 minutes, then cool down to 0 ° C. at a cooling rate of 10 ° C./minute for crystallization The DSC curve at the time of temperature reduction was obtained, and the calorific value (Hc) at the time of crystallization of the stretched film was determined from the obtained DSC curve.

In addition, the peak height was calculated | required by the height from the base line obtained by connecting the base line near 65 to 75 degreeC and the base line near 240 to 250 degreeC.

The thickness of the polylactic acid-based stretched film of the present invention is usually 5 to 500 μm, preferably 10 to 10 μm.
It is in the range of 100 μm.

The polylactic acid-based stretched film of the present invention may be subjected to primer coating, corona treatment, plasma treatment, flame treatment, or the like, as necessary, in order to improve the adhesion with other layers or printing layers.
The polylactic acid-based stretched film of the present invention may be laminated with other base materials depending on the application. Other base materials include, for example, polyolefins such as polyethylene, polypropylene, polybutene and polymethylpentene, polyesters such as polyethylene terephthalate and polycarbonate, nylon, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, and ethylene / vinyl alcohol. Polymer, polymethyl methacrylate, ethylene / vinyl acetate copolymer, polylactic acid, film made of thermoplastic resin such as biodegradable polyester such as aliphatic polyester, sheet, cup, tray, or foam thereof, or Glass, metal, aluminum foil, paper, etc. are mentioned. The film made of a thermoplastic resin may be unstretched or may be a uniaxial or biaxially stretched film. Of course, the substrate may be a single layer or two or more layers.

<Polylactic acid-based composition>
In order to obtain a polylactic acid-based stretched film having the above characteristics of the present invention, a polylactic acid-based composition having the following heat melting characteristics is used as a polylactic acid-based composition containing poly-L-lactic acid and poly-D-lactic acid. It is preferable to prepare and stretch.

In the polylactic acid composition according to the present invention, the polylactic acid composition is 250 in DSC measurement.
When the temperature is lowered after melting at 10 ° C. for 10 minutes (at the first temperature drop), the calorific value (ΔHc) is preferably 20 J / g or more.
Furthermore, the polylactic acid-based composition according to the present invention has a DSC measurement at the second temperature increase (25
The maximum endothermic peak of the endothermic peak in the range of 150 to 200 ° C. of the DSC curve obtained at 10 ° C./min after 10 minutes at 0 ° C. and then increased again at 10 ° C./min from 0 ° C.) The peak ratio (peak 10 / peak 20) between the peak height (peak 10) and the peak endotherm peak height (peak 20) of the endothermic peak in the range of 205-240 ° C. is preferably 0.5 or less, more preferably Preferably has a thermal characteristic of 0.3 or less, particularly preferably 0.2 or less. This is presumably because this composition selectively forms stereocomplex crystals.
If the peak ratio (peak 10 / peak 20) is greater than 0.5, PLLA, P after crystallization
The amount of DLA single crystals formed is large, and poly-L-lactic acid and poly-D-lactic acid may not be sufficiently kneaded. A composition having a peak ratio (Peak 10 / Peak 20) greater than 0.5 has a large amount of α-crystals (PLLA or PDLA single crystal) formed after crystallization. .
Moreover, the polylactic acid-type composition concerning this invention is 205-2 at the time of the 2nd temperature rise of DSC.
The endothermic amount (ΔHm) of the endothermic peak at 40 ° C. is preferably 35 J / g or more.
The heat melting characteristics of the polylactic acid-based composition according to the present invention are the same as the methods for determining the heat-melting characteristics of the stretched polylactic acid film, and DSC (Differential Scanning Calorimeter) is used.
Using Q100 made by Instrument Co., Ltd., weighed about 5 mg of a sample precisely, and JIS K 7121
And it calculated | required based on JISK7122. The heat melting characteristics of the polylactic acid composition are
The characteristics at the time of temperature drop and at the time of the second temperature rise were obtained.

The polylactic acid composition according to the present invention is preferably 25 to 75 parts by weight of the PLLA, more preferably 35 to 65 parts by weight, particularly preferably 45 to 55 parts by weight, and particularly preferably 47 to 53 parts by weight. Preferably PDLA is 75-25 parts by weight, more preferably 65-
It is composed of 35 parts by weight, particularly preferably 55 to 45 parts by weight, and preferably 53 to 47 parts by weight (PLLA + PDLA = 100 parts by weight).

In the polylactic acid-based composition according to the present invention, the poly-L-lactic acid and the poly-D-lactic acid each have a weight average molecular weight in the range of 6,000 to 3,000,000, and -D
-It is desirable to prepare by kneading from poly-L-lactic acid and poly-D-lactic acid having a weight average molecular weight of either lactic acid of 30,000 to 2,000,000.

In addition, the polylactic acid composition according to the present invention includes, for example, these PLLA and PDLA.
It can be obtained by melt-kneading at 30 to 260 ° C. with a twin-screw extruder, twin-screw kneader, Banbury mixer, plast mill or the like.
Even if a composition having an amount of PLLA outside the above range is kneaded by the above-described method, a film formed by stretching the obtained composition contains α-crystals and may have insufficient heat resistance.
The reason why the polylactic acid composition according to the present invention is excellent in heat resistance is that the composition forms a stereocomplex structure, and the stereocomplex structure is composed of equal amounts of PLLA and PDLA. .
In order to obtain the polylactic acid composition according to the present invention, the temperature at which PLLA and PDLA are melt-kneaded is preferably 230 to 260 ° C, more preferably 235 to 255 ° C. If the melt kneading temperature is lower than 230 ° C, the stereocomplex structure may be unmelted, and if it is higher than 260 ° C, polylactic acid may be decomposed.

Moreover, when preparing the polylactic acid-type composition concerning this invention, it is desirable to melt-knead PLLA and PDLA fully. Although the melt-kneading time depends on the melt-kneader used, it is usually 5
It only needs to be over a minute. The longer the melt kneading time of PLLA and PDLA,
For example, by setting the polylactic acid-based composition to 20 minutes or more or 30 minutes or more, the obtained polylactic acid composition has an endothermic amount (ΔHm) of an endothermic peak of 205 to 240 ° C. at the second temperature increase of DSC.
) Is 45 J / g or more, or 50 J / g or more, and the endothermic peak in the range of 150 to 200 ° C. is 3.5 J / g or less, or 0 J / g, and the stereo complex is crystallized faster. While it can be set as the polylactic acid type composition which cannot produce | generate the single crystal (alpha crystal) of PLLA or PDLA, the clarity of the polylactic acid type stretched film obtained increases.

The polylactic acid-based composition according to the present invention is considered to be difficult to produce a single crystal (α crystal) of PLLA or PDLA because the stereocomplex is rapidly crystallized and the stereocomplex crystallizable region is large.

As described above, the polylactic acid-based composition according to the present invention has a peak due to crystallization (a calorific value ΔHc) as measured by DSC at a temperature drop after 10 minutes at 250 ° C. (10 ° C./min).
When it is 20 J / g or more, crystallization of the polylactic acid-based composition occurs rapidly.

On the other hand, if the calorific value due to crystallization is less than 20 J / g, the crystallization rate is low and the kneading may be insufficient.

The weight average molecular weight of the polylactic acid composition according to the present invention is not particularly limited. However, the polylactic acid composition according to the present invention preferably has a weight average molecular weight in the range of 10,000 to 1,500,000, and more preferably in the range of 50,000 to 500,000. If the weight average molecular weight deviates from the above range to the polymer side, stereocomplexation may not be sufficient and heat resistance may not be obtained, and if it deviates to the low molecular side, the strength of the polylactic acid composition layer obtained is sufficient There is a possibility that it is not.

<Method for producing a polylactic acid-based stretched film>
The polylactic acid-based stretched film of the present invention is a film or sheet obtained by extrusion molding using the polylactic acid-based composition containing poly-L-lactic acid and poly-D-lactic acid, preferably in one direction. A stretched film having excellent heat resistance and transparency can be obtained by stretching at least twice, more preferably 2 to 12 times, and even more preferably 3 to 6 times. The upper limit of the stretching ratio is not particularly limited as long as it can be stretched. However, if it exceeds 12 times, the film may be broken or the film may not be stably stretched.

Further, the film or sheet obtained by extrusion molding is preferably at least 2 times in the vertical direction and at least 2 times in the horizontal direction, more preferably 2 to 7 times in the vertical direction and 2 to 7 times in the horizontal direction, still more preferably. Is stretched 2.5 to 5 times in the longitudinal direction and 2.5 to 5 times in the lateral direction, whereby a stretched film (biaxially stretched film) having excellent heat resistance and transparency is obtained. The upper limit of the stretching ratio is not particularly limited as long as it can be stretched. However, if it exceeds 7 times, the film may be broken and may not be stably stretched.
Moreover, in the range which can be extended | stretched favorably, it exists in the tendency for the rigidity and heat resistance of the film obtained to increase, so that it is oriented strongly, so that a draw ratio is high.
Furthermore, biaxial stretching is performed in two stages, MD → TD → MD, and in particular increases the degree of orientation in the MD direction.
The MD direction rigidity and heat resistance may be increased. Naturally, conversely, it may be stretched in two stages in the TD direction.

After stretching, the polylactic acid-based stretched film of the present invention is preferably 140 to 220 ° C, more preferably 150 to 200 ° C, preferably 1 second or more, more preferably 3 to 60 seconds, Heat resistance is improved.

EXAMPLES Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples unless it exceeds the gist.

The polylactic acid used in Examples, Comparative Examples and Reference Examples is as follows.

(A) Poly-L-lactic acid (PLLA-1):
D form amount: 1.9% Mw: 222,000 (g / mol), Tm: 163 ° C.

(B) Poly-L-lactic acid (manufactured by PURAC: PLLA-2):
D body amount: 0.0% Mw: 395,000 (g / mol), Tm: 184 ° C,
Inherent viscosity (chloroform, 25 ° C., 0.1 g / dl): 3.10 (dl / g)

(C) Poly-L-lactic acid (manufactured by PURAC: PLLA-3):
D body amount: 0.0% Mw: 14.3 million (g / mol), Tm: 186 ° C.,
Inherent viscosity (chloroform, 25 ° C., 0.1 g / dl): 7.11 (dl / g)

(2) Poly-D-lactic acid (manufactured by PURAC: PDLA-1):
D body amount: 100.0% Mw: 298,000 (g / mol), Tm: 176 ° C,
Inherent viscosity (chloroform, 25 ° C., 0.1 g / dl): 2.46 (dl / g)

(E) Poly-D-lactic acid (manufactured by PURAC: PDLA-2):
D body amount: 100.0% Mw: 1.35 million (g / mol), Tm: 180 ° C.,
Inherent viscosity (chloroform, 25 ° C., 0.1 g / dl): 7.04 (dl / g)

  The measuring method in the present invention is as follows.

(1-1) Weight average molecular weight (Mw)
The poly-L-lactic acid and poly-D-lactic acid of (i) to (e) were measured by the following method.
To 20 mg of the sample, 10 ml of GPC eluent was added, and the mixture was allowed to stand overnight and then gently stirred by hand.
This solution was added to an amphiphilic 0.45 μm-PTFE filter (ADVANTEC DISM).
IC-25HP045AN) to obtain a GPC sample solution.
Measuring device; Shodex GPC SYSTEM-21
Analysis device; data analysis program: SIC480 data station II
Detector: Differential refraction detector (RI)
Column; Shodex GPC K-G + K-806L + K-806L
Column temperature; 40 ° C. Eluent; Chloroform flow rate; 1.0 ml / min Injection volume; 200 μL molecular weight calibration; Monodisperse polystyrene

(1-2) Weight average molecular weight (Mw)
A polylactic acid composition obtained by melt-kneading poly-L-lactic acid and poly-D-lactic acid was measured by the following method.
A 20 mg sample was dissolved in the mobile phase (concentration 0.5%), and filtered through a 0.45 μm hydrophilic PTFE filter (Millex-LH; Nihon Millipore) to obtain a GPC sample solution.
Column: PL HFIPgel (300 × 7.5 mm) 2 (Polymer la)
(boratories)
Column temperature; 40 ° C. mobile phase; HFIP + 5 mM TFANa flow rate; 1.0 ml / min detection; RI
Injection volume: 50 μL
Measuring device: 510 high pressure pump, U6K
Water injection system, 410 differential refractometer (Japan Waters)
Molecular weight calibration; monodisperse PMMA (Easi Cal PM-1; Polymer lab
oratories)

(2) DSC measurement It measured by the method of the said description.

(3) Transparency The haze (HZ) and parallel light ray transmittance (PT) of the film were measured using a haze meter 300A manufactured by Nippon Denshoku Industries Co., Ltd.

(4) Surface roughness The center surface average roughness (SRa) of the film surface was measured using a three-dimensional surface roughness measuring instrument SE-30K manufactured by Kosaka Laboratory.

(5) Tensile test Strip-shaped test pieces (length: 50 or 15) in the MD direction and TD direction from the film, respectively.
0 mm, width: 15 mm), and using a tensile tester (Orientec Tensilon Universal Tester RTC-1225), chuck distance: 20 mm or 100 mm, crosshead speed: 300 mm / min (however, Young Rate is measured at 5 mm / min)
A tensile test was performed to determine tensile strength (MPa), elongation (%), and Young's modulus (MPa).
However, in Example 1 and Comparative Example 1, the distance between chucks was 100 mm, but in Examples 2 to 6 and Comparative Examples 2 to 6, the distance between chucks was 20 mm.

(6) Heat resistance Thermal analyzer (Thermal / application / strain measuring device TMA /
A test piece having a width of 4 mm was cut out from the film using SS120), a load of 0.25 MPa was applied to the test piece with a chuck distance of 5 mm, and the temperature was raised from 100 ° C. (starting temperature) at 5 ° C./min. The deformation (elongation or shrinkage) was measured.

(7) Wide-angle X-ray measurement Measurement of Example 1 and Comparative Example 1 Measuring device: X-ray diffractometer (Rigaku Corporation automatic X-ray diffractometer RINT-2200)
Reflective X-ray target; Cu
K-α output: 40 kV x 40 mA
Rotation angle: 4.0 degrees / minute step; 0.02 degrees Scanning range: 10-30 degrees

Measurement of Examples 2-6, Examples 10-14, and Comparative Examples 2-5 Measuring apparatus: X-ray diffractometer (automatic X-ray diffractometer RINT-2500 manufactured by Rigaku Corporation)
Transmission X-ray target: Cu
K-α output: 50 kV x 300 mA
Rotation angle: 2.0 degrees / minute Step: 0.01 degrees Scanning range: 5-30 degrees

(8) Moisture permeability (water vapor permeability)
It calculated | required based on JISZ0208. Take a film and the surface area is about 100cm
^After making a bag of ² and adding an appropriate amount of calcium chloride, it was sealed. This is 40 ° C., 90% RH (
(Relative humidity) was left in an atmosphere for 3 days, and the moisture permeability (water vapor permeability) was determined from the weight increase.

(9) Oxygen permeability Based on JIS K7126, the oxygen permeability was measured using an oxygen permeation measuring instrument (manufactured by MOCON, OXTRAN2 / 21 ML) under the conditions of 20 ° C. and 0% RH (relative humidity).
(10) Plane orientation degree of film It measured at 23 degreeC using Abbe refractometer DR-M2 type | mold made by Atago Co., Ltd.

Example 1
PLLA-1: PDLA-2 was weighed at a ratio of 50:50 (parts by weight), and melted and kneaded at a melting temperature of 250 ° C. and a kneading time of 1 minute using a twin-screw kneading extruder. After obtaining the product, a sheet made of a polylactic acid-based composition having a thickness of about 300 μm was obtained with a T-die sheet molding machine.
This twin-screw kneading extruder has a capacity of 40 kg / h, but the amount of extrusion is about several tens of seconds. Since kneading was insufficient, the kneading time was increased to 6 minutes by reducing the extrusion rate to 7 kg / h.
The heat melting characteristics of the polylactic acid composition were measured by the method described above.
Next, the sheet was stretched in a longitudinal direction by a biaxial stretching machine manufactured by Bruckner; 3 times at 65 ° C., a stretching temperature in the transverse direction; 3 times at 70 ° C., and about 180 ° C. in a tenter. Heat setting was performed for 40 seconds to obtain a polylactic acid-based stretched film. The physical properties of the obtained polylactic acid-based stretched film were measured by the method described above.
The measurement results are shown in Table 1, and the thermal melting characteristics are shown in FIGS.

Comparative Example 1
Instead of PLLA-1 and PDLA-1 used in Example 1, PLLA-1 is used alone, except that heat setting of the biaxially stretched film is performed at 150 ° C. for about 40 seconds, and performed in the same manner as in Example 1. A sheet of PLLA-1 and a biaxially stretched film were obtained.
The measurement results are shown in Table 1, and the thermal melting characteristics are shown in FIGS.

As is clear from Table 1, the biaxially stretched film made of the polylactic acid composition obtained in Example 1 has a slight endothermic peak (endothermic amount) in the range of 150 to 200 ° C. in the heat melting characteristics. The endothermic peak in the range of 205 to 240 ° C. is large, the endothermic amount (ΔHm) is as large as 66.1 J / g, and the calorific value (ΔHc) when the temperature is lowered is 49.7 J / g.
The heat melting characteristics of the polylactic acid-based composition (sheet) used as the material for the biaxially stretched film are as follows. The calorific value (ΔHc) at the first temperature drop is 20.3 J / g, and at the second temperature rise, 150 to No endothermic peak is observed in the range of 200 ° C., and the endothermic amount (ΔHm) of the endothermic peak in the range of 205 to 240 ° C. is 51.0 J / g.
Furthermore, the biaxially stretched film comprising the polylactic acid-based composition obtained in Example 1 is transparent,
Excellent heat resistance, low moisture permeability and low oxygen permeability, barrier performance, and peak areas (S _SC ) around 12 degrees, 21 degrees and 24 degrees in wide-angle X-ray measurement are 50. 9% and 20% or more, and 2θ is 17 degrees and the peak area around 19 degrees (S _PL ) is 0.0% and 5% or less with respect to the entire area. Therefore, it can be seen that the crystallized portion has a stereo complex structure, and the ratio is large.

On the other hand, the biaxially stretched film made of PLLA-1 obtained in Comparative Example 1 is 150 to
Only the endothermic peak in the range of 200 ° C., no endothermic peak in the range of 205 to 240 ° C., and the calorific value (ΔHc) when the temperature is lowered is 0.4 J / g, which is the polylactic acid composition obtained in Example 1 Less than the biaxially stretched film made of
In addition, the thermal melting characteristics of PLLA-1 (sheet), which is a material of the biaxially stretched film, has a calorific value (ΔHc) of 0 at the first temperature drop, and a range of 205 to 240 ° C. at the second temperature rise. Shows no endothermic peak, only a peak in the range of 150 to 200 ° C., and its endothermic amount (ΔH
m) is 32.1 J / g.
Furthermore, the biaxially stretched film made of PLLA-1 obtained in Comparative Example 1 is excellent in transparency but inferior in heat resistance and barrier performance, and has a diffraction peak of 12 in wide-angle X-ray measurement.
The peak area (S _SC ) around 15 degrees, 21 degrees, and 24 degrees is 0.0% of the entire area,
And 2θ is 17 degrees and the peak area around 19 degrees (S _PL ) is 57.3% of the total area.
It is. Therefore, it can be seen that the crystallized portion does not contain a stereocomplex structure.

Example 2
<Manufacture of press sheet made of polylactic acid-based composition>
PLLA-1: PDLA-2 was weighed at a ratio of 50:50 (parts by weight) at 80 g, and 2 using a Toyo Seiki Laboplast Mill C model (biaxial kneader) at 250 ° C. and 120 rpm.
It was melt-kneaded for 0 minutes to obtain a polylactic acid composition.
Subsequently, the polylactic acid composition was press-molded to obtain a press sheet made of the polylactic acid composition having a thickness of 500 μm.
<Manufacture of biaxially stretched film>
The press sheet was preheated with 75 ° C. hot air for 60 seconds using a pantograph batch biaxial stretching apparatus (Brookner), and then stretched 3.0 times in the longitudinal and transverse directions at a speed of 2.1 m / min (simultaneous). Biaxially stretched) to obtain a biaxially stretched film having a thickness of about 50 μm.
Next, the obtained biaxially stretched film was fixed to a metal frame with a clip, heat-set (heat treated) at 200 ° C. for 15 minutes, and then sufficiently cooled at room temperature to obtain a polylactic acid-based biaxially stretched film.

The press sheet and polylactic acid biaxially stretched film which consisted of the obtained polylactic acid-type composition were measured by the method of the said description. The measurement results are shown in Table 2.

Example 3
A polylactic acid composition and a polylactic acid biaxially stretched film were obtained in the same manner as in Example 2 except that PLLA-3 was used instead of PLLA-1 used in Example 2.

The press sheet and polylactic acid biaxially stretched film which consisted of the obtained polylactic acid-type composition were measured by the method of the said description.
The measurement results are shown in Table 2.

Example 4
Instead of PLLA-1 used in Example 2, PLLA-3 was replaced with PDLA- used in Example 2.
A polylactic acid composition and a polylactic acid biaxially stretched film were obtained in the same manner as in Example 2 except that PDLA-1 was used instead of 2.

The press sheet and polylactic acid biaxially stretched film which consisted of the obtained polylactic acid-type composition were measured by the method of the said description.
The measurement results are shown in Table 2.

Example 5
A polylactic acid-based composition and a polylactic acid-based biaxially stretched film were obtained in the same manner as in Example 2 except that PLLA-2 was used instead of PLLA-1 used in Example 2.

The press sheet and polylactic acid biaxially stretched film which consisted of the obtained polylactic acid-type composition were measured by the method of the said description.
The measurement results are shown in Table 2.

Example 6
Instead of PLLA-1 used in Example 2, PLLA-2 was replaced by PDLA- used in Example 2.
A polylactic acid composition and a polylactic acid biaxially stretched film were obtained in the same manner as in Example 2 except that PDLA-1 was used instead of 2.

The press sheet and polylactic acid biaxially stretched film which consisted of the obtained polylactic acid-type composition were measured by the method of the said description. The measurement results are shown in Table 2.

Comparative Example 2
The composition and the biaxially stretched film were prepared in the same manner as in Example 2, except that the polylactic acid composition used in Example 2 was replaced by a kneaded product obtained by setting the kneading time in the lab plast mill to 3 minutes. Obtained.

The obtained press sheet and biaxially stretched film were measured by the method described above. The measurement results are shown in Table 2.

Comparative Example 3
The composition and the biaxially stretched film were prepared in the same manner as in Example 2 except that the kneaded product obtained by changing the polylactic acid-based composition used in Example 4 to 3 minutes in the lab plast mill was used. Obtained.

The obtained press sheet and biaxially stretched film were measured by the method described above.
The measurement results are shown in Table 2.

Comparative Example 4
The composition and the biaxially stretched film were prepared in the same manner as in Example 2 except that the kneaded material obtained by replacing the polylactic acid-based composition used in Example 6 with a lab plast mill for 3 minutes was used. Obtained.

The obtained press sheet and biaxially stretched film were measured by the method described above.
The measurement results are shown in Table 2.

As shown in Examples 2 to 6 in Table 2, all of the polylactic acid-based stretched films of the present invention are DS.
Maximum endothermic peak of the endothermic peak in the range of 150 to 200 ° C. in C measurement (peak 1)
The peak ratio (peak 1 / peak 2) to the maximum endothermic peak (peak 2) of the endothermic peak in the range of 205 to 240 ° C. is 0.06 to 0.18, both being 0.2 or less, 2
The endothermic amount of the endothermic peak in the range of 40 ° C. is 45.0 to 62.4 J / g, both 40 J / g.
The amount of heat generated when the temperature is lowered is 46.1 to 71.4 J / g, both of which are 40 J / g or more, indicating that the heat resistance is excellent.
Moreover, in order to obtain the polylactic acid-type stretched film which has this heat melting characteristic, the calorific value at the time of the 1st temperature fall of a polylactic acid-type composition is large, and the endotherm in the range of 150-200 degreeC at the time of the 2nd temperature rise. A polylactic acid-based composition having a peak ratio (peak 10 / peak 20) between the maximum endothermic peak (peak 10) and the endothermic peak (peak 20) in the range of 205 to 240 ° C. of 0.5 or less. It can be seen that it is preferable to use.
In Examples 2 to 6, peak areas in the vicinity of 12 degrees, 21 degrees, and 24 degrees in wide-angle X-ray measurement (
S _SC) is not less 24-32% and more than 20% relative to the total area, and 2θ is 17 °, 1
The peak area (S _PL ) around 9 degrees is 0% and 5% or less with respect to the entire area.
Therefore, it can be seen that the crystallized portion has a stereo complex structure, and the ratio is large.
On the other hand, even if poly-L-lactic acid and poly-D-lactic acid having the same mixing ratio as in Examples 2, 4, 5, and 6 were used, the stretched films of Comparative Examples 2 to 5 were 150 to 200 ° C. in DSC measurement. The peak ratio (peak 1 / peak 2) of the maximum endothermic peak (peak 1) in the endothermic range to the maximum endothermic peak (peak 2) in the range from 205 to 240 ° C. is 0.73 to 1
. It exceeds 39 and 0.2, and it turns out that it is inferior to heat resistance.
Moreover, the 2nd of the kneaded material (press sheet) used as a raw material of the stretched film of Comparative Examples 2-4.
Maximum endothermic peak of the endothermic peak in the range of 150 to 200 ° C. during peak temperature rise (peak 1
0) and the maximum endothermic peak (peak 20) of the endothermic peak in the range of 205 to 240 ° C. (peak 10 / peak 20) exceeds 1.50 to 4.00 and 0.5.
In Comparative Examples 2 to 5, peak areas in the vicinity of 12 degrees, 21 degrees, and 24 degrees in wide-angle X-ray measurement (
S _SC ) is 5 to 19% and less than 20% with respect to the entire area, and 2θ is 17 degrees, 19
The peak area (S _PL ) in the vicinity of the temperature is 18% and 5% larger than the total area, and Comparative Examples 3 to 5 are 0%. Therefore, it can be seen that the crystallized portion does not have a sufficient stereocomplex structure, or the ratio is small.

Example 7
A polylactic acid-based composition and a polylactic acid-based biaxially stretched film were obtained in the same manner as in Example 2 except that PDLA-1 was used instead of PDLA-2 used in Example 2, and the kneading time was 30 minutes. Got.
The press sheet and polylactic acid biaxially stretched film which consisted of the obtained polylactic acid-type composition were measured by the method of the said description.
Table 3 shows the measurement results.

Example 8
A polylactic acid composition and a polylactic acid biaxially stretched film were prepared in the same manner as in Example 2 except that PDLA-1 was used instead of PDLA-2 used in Example 2 and the kneading time was 40 minutes. Got.
The press sheet and polylactic acid biaxially stretched film which consisted of the obtained polylactic acid-type composition were measured by the method of the said description.
Table 3 shows the measurement results.

Example 9
A polylactic acid composition and a polylactic acid biaxially stretched film were obtained in the same manner as in Example 2 except that the kneading time was 30 minutes.
The press sheet and polylactic acid biaxially stretched film which consisted of the obtained polylactic acid-type composition were measured by the method of the said description.
Table 3 shows the measurement results.



As shown in Examples 7 to 9 of Table 3, the polylactic acid-based stretched film of the present invention has a long kneading time, and further has a maximum endothermic peak (peak) in the range of 150 to 200 ° C. in DSC measurement. The peak ratio (peak 1 / peak 2) between 1) and the maximum endothermic peak (peak 2) of the endothermic peak in the range of 205 to 240 ° C. is small, and the endothermic amount of the endothermic peak in the range of 240 ° C. It turns out that the calorific value of becomes large.
Further, in order to obtain a polylactic acid-based stretched film having such heat melting characteristics, the amount of heat generated when the polylactic acid-based composition is first lowered in temperature is large when the kneading time is long.
Maximum endothermic peak (peak 10) of endothermic peak in the range of ~ 200 ° C and 205-240 ° C
It can be seen that the peak ratio (peak 10 / peak 20) to the maximum endothermic peak (peak 20) of the endothermic peak in the range is small.
Further, when the films of Examples 7, 8, and 9 were placed side by side and located at a position 30 cm from the eyes and the lamp of a fluorescent lamp 8 m ahead was viewed, Example 7 was slightly mixed with a fluorescent lamp image of 30 minutes. In contrast to the blurred outline, in Example 8 where the kneading time is 40 minutes, the outline of the fluorescent lamp image is clearly visible.
This appearance is similar to that in Example 9 in which the kneading time is 30 minutes using PDLA2 having a high molecular weight.
From this, it is clear that the clarity of the film is improved if the kneading time is increased.
It is also clear that the clarity of the film using DPLA having a high molecular weight is improved.

Example 10
Using the sheet made of the polylactic acid composition having a thickness of about 300 μm obtained in Example 1, the pantograph batch biaxial stretching apparatus (manufactured by Bruckner) was used.
Preheating: 75 ° C x 1 minute (hot air)
Stretch ratio: 3 × 3
Method: Simultaneous biaxial stretching speed: 2.1 m / min Relaxation rate: 2.5%
Heat set: 200 ° C. × 1 minute The obtained biaxially stretched film was measured by the method described above. Table 4 shows the measurement results.

Example 11
A biaxially stretched film was obtained in the same manner as in Example 10 except that the stretching method was sequentially changed to a biaxial magnification of 3 × 3 (MD → TD).
The obtained biaxially stretched film was measured by the method described above. Table 4 shows the measurement results.

Example 12
A biaxially stretched film was obtained in the same manner as in Example 10 except that the stretching method was simultaneously biaxial magnification 4 × 4.
The obtained biaxially stretched film was measured by the method described above. Table 4 shows the measurement results.

Example 13
A biaxially stretched film was obtained in the same manner as in Example 10 except that the stretching method was successively changed to biaxial magnification 4 × 4 (MD → TD).
The obtained biaxially stretched film was measured by the method described above. Table 4 shows the measurement results.

Example 14
A biaxially stretched film was obtained in the same manner as in Example 10 except that the stretching method was changed to a two-stage sequential biaxial magnification of 3 × 4 × 1.3 (MD → TD → MD).
The obtained biaxially stretched film was measured by the method described above. Table 4 shows the measurement results.

As shown in Examples 10 to 14 of Table 4, all of the polylactic acid-based stretched films of the present invention have a maximum endothermic peak (peak 1) and 205 to 240 of the endothermic peak in the range of 150 to 200 ° C. in DSC measurement. The peak ratio (peak 1 / peak 2) of the endothermic peak in the range of ° C to the maximum endothermic peak (peak 2) is 0.09 to 0.12, both being 0.2 or less, and the range of 205 to 240 ° C. The endothermic amount of the endothermic peak is 57.2 to 63.2 J / g, and it can be seen that crystals having an SC structure are formed preferentially and have excellent heat resistance.
Moreover, compared with Examples 10-14, Examples 12-14, which have a higher draw ratio, have a higher degree of plane orientation, higher film rigidity and breaking strength than Examples 10-12, and TMA elongation in the MD direction. In the practical use range of 100 to 160 ° C., the rate of change was smaller than those in Examples 10 and 11. In particular, Examples 13 and 14 formed by sequential biaxial and two-stage biaxial are excellent in heat resistance with a change amount of 100 to 160 ° C. being 1% or less.

The composition of the present invention has specific thermal properties. This is presumably because the stereocomplex structure is easily and selectively formed.
For this reason, the stretched film is superior in heat resistance and toughness as compared to a molded product such as a conventional polylactic acid-based stretched film, and is further excellent in surface smoothness, transparency, and thermal stability.

This is because a stereocomplex structure is selectively formed upon crystallization from an amorphous state, and the crystallization treatment is easy with the composition of the present invention.

1 is a chart showing a DSC measurement chart of the first temperature increase of the stretched film of Example 1. FIG. 2 is a chart showing a DSC measurement chart of the first temperature drop of the stretched film of Example 1. FIG. 3 is a chart showing a DSC measurement chart of the second temperature increase of the stretched film of Example 1. FIG. 4 is a diagram showing a DSC measurement chart of the first temperature increase of the stretched film of Comparative Example 1. FIG. FIG. 5 is a diagram showing a DSC measurement chart of the first temperature drop of the stretched film of Comparative Example 1. 6 is a chart showing a DSC measurement chart of the second temperature increase of the stretched film of Comparative Example 1. FIG. 7 is a chart showing a DSC measurement chart of the first temperature drop of a sheet (unstretched) made of the polylactic acid-based composition of Example 1. FIG. FIG. 8 is a diagram showing a DSC measurement chart of the second temperature increase of a sheet (unstretched) made of the polylactic acid-based composition of Example 1. FIG. 9 is a chart showing a DSC measurement chart of the first temperature drop of a sheet (unstretched) made of the polylactic acid-based composition of Comparative Example 1. FIG. 10 is a diagram showing a DSC measurement chart of the second temperature rise of a sheet (unstretched) made of the polylactic acid-based composition of Comparative Example 1. FIG. 11 shows the results of wide-angle X-ray diffraction measurement of the stretched film of Example 1. FIG. 12 is a view showing a wide-angle X-ray diffraction measurement result of the stretched film of Comparative Example 1. FIG. 13 is a chart showing a DSC measurement chart of the first temperature rise of the stretched film of Example 2. 14 is a chart showing a DSC measurement chart of the first temperature drop of the stretched film of Example 2. FIG. FIG. 15 is a chart showing a DSC measurement chart of the second temperature increase of the stretched film of Example 2. 16 is a chart showing a DSC measurement chart of the first temperature drop of a sheet (unstretched) made of the polylactic acid-based composition of Example 2. FIG. FIG. 17 is a diagram showing a DSC measurement chart of second temperature increase of a sheet (unstretched) made of the polylactic acid composition of Example 2. 18 is a chart showing a DSC measurement chart of first temperature increase of the stretched film of Example 3. FIG. 19 is a chart showing a DSC measurement chart of the first temperature drop of the stretched film of Example 3. FIG. FIG. 20 is a diagram showing a DSC measurement chart of the second temperature increase of the stretched film of Example 3. 21 is a chart showing a DSC measurement chart of the first temperature drop of a sheet (unstretched) made of the polylactic acid-based composition of Example 3. FIG. FIG. 22 is a diagram showing a DSC measurement chart of the second temperature increase of a sheet (unstretched) made of the polylactic acid-based composition of Example 3. FIG. 23 is a diagram showing a DSC measurement chart of the first temperature increase of the stretched film of Example 4. FIG. 24 is a chart showing a DSC measurement chart of the first temperature drop of the stretched film of Example 4. 25 is a chart showing a DSC measurement chart of second temperature increase of the stretched film of Example 4. FIG. 26 is a chart showing a DSC measurement chart of the first temperature drop of a sheet (unstretched) made of the polylactic acid composition of Example 4. FIG. FIG. 27 is a chart showing a DSC measurement chart of second temperature increase of a sheet (unstretched) made of the polylactic acid-based composition of Example 4. 28 is a chart showing a DSC measurement chart of the first temperature increase of the stretched film of Example 5. FIG. FIG. 29 is a chart showing a DSC measurement chart of the first temperature drop of the stretched film of Example 5. 30 is a chart showing a DSC measurement chart of second temperature increase of the stretched film of Example 5. FIG. FIG. 31 is a chart showing a DSC measurement chart of the first temperature drop of a sheet (unstretched) made of the polylactic acid-based composition of Example 5. FIG. 32 is a diagram showing a DSC measurement chart of second temperature increase of a sheet (unstretched) made of the polylactic acid-based composition of Example 5. FIG. 33 is a diagram showing a DSC measurement chart of first temperature increase of the stretched film of Example 6. FIG. 34 is a chart showing a DSC measurement chart of the first temperature drop of the stretched film of Example 6. FIG. 35 is a diagram showing a DSC measurement chart of second temperature increase of the stretched film of Example 6. 36 is a chart showing a DSC measurement chart of the first temperature drop of a sheet (unstretched) made of the polylactic acid-based composition of Example 6. FIG. FIG. 37 is a diagram showing a DSC measurement chart of second temperature increase of a sheet (unstretched) made of the polylactic acid-based composition of Example 6. 38 is a diagram showing a DSC measurement chart of the first temperature increase of the stretched film of Comparative Example 2. FIG. FIG. 39 is a diagram showing a DSC measurement chart of the first temperature drop of the stretched film of Comparative Example 2. 40 is a diagram showing a DSC measurement chart of second temperature increase of the stretched film of Comparative Example 2. FIG. 41 is a chart showing a DSC measurement chart of the first temperature drop of a sheet (unstretched) made of the polylactic acid-based composition of Comparative Example 2. FIG. FIG. 42 is a diagram showing a DSC measurement chart of the second temperature increase of a sheet (unstretched) made of the polylactic acid-based composition of Comparative Example 2. FIG. 43 is a diagram showing a DSC measurement chart of the first temperature increase of the stretched film of Comparative Example 3. FIG. 44 is a diagram showing a DSC measurement chart of the first temperature drop of the stretched film of Comparative Example 3. 45 is a chart showing a DSC measurement chart of second temperature increase of the stretched film of Comparative Example 3. FIG. 46 is a diagram showing a DSC measurement chart of the first temperature drop of a sheet (unstretched) made of the polylactic acid-based composition of Comparative Example 3. FIG. 47 is a diagram showing a DSC measurement chart of second temperature increase of a sheet (unstretched) made of the polylactic acid-based composition of Comparative Example 3. FIG. FIG. 48 is a diagram showing a DSC measurement chart of the first temperature increase of the stretched film of Comparative Example 4. 49 is a chart showing a DSC measurement chart of the first temperature drop of the stretched film of Comparative Example 4. FIG. 50 is a diagram showing a DSC measurement chart of second temperature increase of the stretched film of Comparative Example 4. FIG. 51 is a diagram showing a DSC measurement chart of the first temperature drop of a sheet (unstretched) made of the polylactic acid-based composition of Comparative Example 4. FIG. 52 is a diagram showing a DSC measurement chart of second temperature increase of a sheet (unstretched) made of the polylactic acid-based composition of Comparative Example 4. FIG. 53 is a diagram showing a DSC measurement chart of first temperature increase of a stretched film of Comparative Example 5. FIG. FIG. 54 is a diagram showing a DSC measurement chart of the first temperature drop of the stretched film of Comparative Example 5. 55 is a chart showing a DSC measurement chart of second temperature increase of the stretched film of Comparative Example 5. FIG. FIG. 56 is a diagram showing a DSC measurement chart of the first temperature drop of a sheet (unstretched) made of the polylactic acid-based composition of Comparative Example 5. FIG. 57 is a diagram showing a DSC measurement chart of second temperature increase of a sheet (unstretched) made of the polylactic acid-based composition of Comparative Example 5. 58 is a diagram showing the results of wide-angle X-ray diffraction measurement of the stretched film of Example 2. FIG. FIG. 59 shows the results of wide-angle X-ray diffraction measurement of the stretched film of Example 3. FIG. 60 shows the results of wide-angle X-ray diffraction measurement of the stretched film of Example 4. 61 is a view showing a wide-angle X-ray diffraction measurement result of the stretched film of Example 5. FIG. FIG. 62 is a view showing a wide-angle X-ray diffraction measurement result of the stretched film of Example 6. FIG. 63 is a view showing a wide-angle X-ray diffraction measurement result of the stretched film of Comparative Example 2. FIG. 64 is a view showing a wide-angle X-ray diffraction measurement result of the stretched film of Comparative Example 3. 65 is a view showing a wide-angle X-ray diffraction measurement result of the stretched film of Comparative Example 4. FIG. 66 is a view showing a wide-angle X-ray diffraction measurement result of the stretched film of Comparative Example 5. FIG. 67 is a chart showing DSC measurement chart of first temperature increase of the stretched film of Example 10. FIG. 68 is a chart showing DSC measurement chart of first temperature drop of the stretched film of Example 10. FIG. FIG. 69 is a chart showing a DSC measurement chart of second temperature rise of the stretched film of Example 10. 70 is a chart showing DSC measurement chart of first temperature increase of the stretched film of Example 11. FIG. 71 is a chart showing DSC measurement chart of first temperature drop of the stretched film of Example 11. FIG. 72 is a chart showing DSC measurement chart of second temperature increase of the stretched film of Example 11. FIG. 73 is a chart showing DSC measurement chart of first temperature increase of the stretched film of Example 12. FIG. 74 is a chart showing DSC measurement chart of first temperature drop of the stretched film of Example 12. FIG. 75 is a chart showing DSC measurement chart of second temperature increase of the stretched film of Example 12. FIG. 76 is a chart showing DSC measurement chart of first temperature increase of a stretched film of Example 13. FIG. 77 is a chart showing DSC measurement chart of first temperature drop of the stretched film of Example 13. FIG. 78 is a chart showing DSC measurement chart of second temperature increase of the stretched film of Example 13. FIG. FIG. 79 is a chart showing DSC measurement chart of first temperature increase of the stretched film of Example 14. 80 is a chart showing DSC measurement chart of first temperature drop of the stretched film of Example 14. FIG. FIG. 81 is a chart showing DSC measurement chart of second temperature increase of the stretched film of Example 14. 82 is a view showing a wide-angle X-ray diffraction measurement result of the stretched film of Example 10. FIG. FIG. 83 is a view showing a wide-angle X-ray diffraction measurement result of the stretched film of Example 11. 84 is a view showing a wide-angle X-ray diffraction measurement result of the stretched film of Example 12. FIG. 85 is a view showing a wide-angle X-ray diffraction measurement result of the stretched film of Example 13. FIG. FIG. 86 is a view showing a wide-angle X-ray diffraction measurement result of the stretched film of Example 14.

Claims (11)

  It consists of a polylactic acid-based composition containing poly-L-lactic acid and poly-D-lactic acid, and the peak endothermic peak height (peak 1) and 205-240 in the range of 150 to 200 ° C. in the DSC measurement. A polylactic acid-based stretched film having a peak ratio (peak 1 / peak 2) to a peak height (peak 2) of an endothermic peak in a range of ° C. of 0.2 or less.   The polylactic acid-based stretched film according to claim 1, wherein an endothermic amount of an endothermic peak in the range of 205 to 240 ° C is 40 J / g or more.   The polylactic acid-based stretched film according to claim 1 or 2, wherein after the endothermic peak measurement in the DSC measurement, the calorific value when the temperature is lowered is 40 J / g or more. Sum of peak areas around 2 ° in the wide-angle X-ray measurement of 12 °, 21 ° and 24 ° (S
_SC) is not less than 20% relative to the whole area, and claims 1 to 3 2 [Theta] is less than 5% relative to the total _{(S PL)} is the total area of the peak area of around 17 degrees and 19 degrees The polylactic acid-type stretched film in any one of.   The stretched polylactic acid film according to any one of claims 1 to 4, which is obtained by stretching a polylactic acid composition having a calorific value of 20 J / g or more when the temperature is lowered after 250 minutes at 250 ° C in DSC measurement.   In DSC measurement, the peak height of the endothermic peak in the range of 150 to 200 ° C. at the second temperature rise (peak 10) and the peak endothermic peak of the endothermic peak in the range of 205 to 240 ° C. The stretched polylactic acid film according to any one of claims 1 to 4, which is obtained by stretching a polylactic acid composition having a peak ratio (peak 10 / peak 20) to the thickness (peak 20) of 0.5 or less.   5. The polylactic acid composition obtained by stretching a polylactic acid-based composition having an endothermic peak of 35 J / g or more in the range of 205 to 240 ° C. in the second temperature increase in DSC measurement. Polylactic acid stretched film.   The polylactic acid composition comprises 75 to 25 parts by weight of poly-L-lactic acid and 25 to 75 parts by weight of poly-D-lactic acid (100 parts by weight in total of poly-L-lactic acid and poly-D-lactic acid). Item 2. The polylactic acid-based stretched film according to Item 1.   The polylactic acid-based stretched film according to any one of claims 1 to 8, which is stretched twice in at least one direction.   The polylactic acid-based stretched film according to any one of claims 1 to 8, which is stretched twice or more in the longitudinal direction and twice or more in the transverse direction.   The polylactic acid-based stretched film according to any one of claims 1 to 10, which is heat-treated at 140 to 220 ° C for 1 second or longer.