JP2011038099A - Polylactic acid-based composition and polylactic acid-based film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polylactic acid-based composition having antistatic ability, excellent adhesiveness in film formation and printability. <P>SOLUTION: The polylactic acid-based composition includes a polylactic acid-based polymer (A), and a polyetheresteramide polymer (B), which is obtained by mixing the component (A) with the component (B) in a mass ratio of 95:5-65:35. A polylactic-based film having a contexture of a single layer includes a resin layer containing the polylactic acid-based composition. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a polylactic acid composition comprising a polylactic acid polymer as a main component and a polylactic acid film using the polylactic acid composition.

  Thermoplastics manufactured from petroleum-derived raw materials have been used in various applications because of their excellent water resistance, moldability, strength, etc. On the other hand, they have serious problems in terms of disposal. It was. That is, this kind of plastic product remains in the soil semipermanently because it has high chemical stability and hardly decomposes in the natural environment even when disposed of in landfills. Even if incinerated, the amount of heat generated at the time of combustion may cause damage to the combustion furnace during the combustion process, and there is a concern about the impact on the environment such as the discharge of carbon dioxide by the combustion process. . In particular, since the conclusion of the Kyoto Protocol, the momentum for reducing carbon dioxide emissions has increased rapidly, and the transition to recyclable materials has been promoted.

  As specific measures for introducing the recycling material, for example, active recycling of plastics, so-called material recycling, chemical recycling for depolymerizing and reusing the monomer has been attempted. However, since it is necessary to design the product in the previous stage and to sort by type, there is no significant progress in plastic products other than PET bottles. On the other hand, development of plastic products made of biodegradable resins has been actively promoted in recent years.

  Among the biodegradable resins, “polylactic acid” is a technology that ferments and synthesizes from starch obtained from plants, and is a resin that uses carbon dioxide in the atmosphere as a carbon source. The amount of carbon dioxide in the atmosphere can be regarded as substantially zero, and the amount of combustion heat is less than half that of polyethylene. Moreover, the biodegradable resin is also excellent in that hydrolysis proceeds spontaneously in soil and water and becomes a harmless degradation product by microorganisms.

  Polylactic acid is excellent in transparency, so it is suitable as a material for containers such as films, sheets, and bottles. Polyolefins, polystyrenes, acrylics, aromatics conventionally used for these raw materials Expected to be an alternative to polyester, the amount used is steadily increasing.

Furthermore, a film using polylactic acid has a feature of high moisture permeability as compared with other plastic films, and is also used for applications utilizing this point.
For example, in the packaging of fruits and vegetables, when water droplets are formed on the inside of the plastic packaging material, there arises a problem that the fruits and vegetables that are the packages are damaged, so that a highly moisture permeable material is preferred. In particular, a highly moisture-permeable polylactic acid-based film is particularly suitable for such applications because citrus fruits, leaves, and mushrooms are more beneficial for packaging.
Further, taking advantage of the feature of high moisture permeability, for example, as disclosed in Patent Document 1, a protective material for electronic parts, particularly a polarizing sheet, a retardation sheet, an antireflection sheet, and other protective films for liquid crystal members, etc. For example, Patent Document 2 discloses a surface protective film for an optical film using polylactic acid. This type of optical sheet is generally used as a liquid crystal module that is laminated and fixed with a fixed frame. After the liquid crystal module is manufactured, it is incorporated into the housing of the product in the next process to become a product. However, a transparent plastic protective film is applied to prevent dust and dirt from adhering to the distribution process. In the next process, the film is peeled off once. However, if the moisture permeability of the protective film is low, the moisture taken into the display part of this liquid crystal module is low before peeling, and the moisture is largely absorbed after peeling. Therefore, the color of the display unit may change. In particular, if there is uneven pasting on the protective film, when pasted with air bubbles or wrinkles, the degree of moisture absorption varies, and the color of the liquid crystal module changes, resulting in uneven color. Originally, since the protective film is peeled off when used, it is required that the color does not change regardless of the presence or absence of the protective film, and specifically, high moisture permeability is preferred.

  Thus, polylactic acid has properties superior to those of other plastics, but at the same time, it has the following problems to be solved, and a solution means has been proposed.

  For example, an unstretched film made of polylactic acid is excellent in thermoformability as described in Patent Document 3, but it may be difficult in terms of practicality unless its molding magnification is adjusted. It has been proposed to improve impact resistance by mixing other aliphatic polyester as in Patent Document 4.

In addition, the unstretched film of polylactic acid has an elongation of only a few percent and has a problem that it is brittle. Therefore, it is not necessarily practical as it is for certain uses such as packaging and printing / recording. . Therefore, by stretching the film uniaxially or biaxially, the film is oriented to increase the elongation, and further heat treatment is performed to obtain a highly practical film that suppresses heat shrinkability ( (See Patent Document 5 and Patent Document 6).
However, since such a polylactic acid-based stretched film is crystallized by stretching, there arises a new problem that adhesiveness and printability are lowered. That is, the wetting index on the surface of the crystallized polylactic acid is generally low, and is about 360 μN / cm or less, resulting in insufficient adhesion and ink adhesion.
Therefore, in general, the film surface is oxidized to improve the wettability like corona treatment or plasma treatment, but the film surface is physically or chemically treated such as corona treatment or plasma treatment. In order to perform the processing, it is necessary to install a processing apparatus, and a space to be incorporated into the current equipment is required. In some cases, it is necessary to modify the configuration of the production line itself, which requires a large amount of cost. As another means for improving the wettability, there is a method of unwinding and processing again after film formation. However, this method also requires installation cost of equipment, and the work is troublesome twice. Most importantly, the wettability of the film when treated with these materials gradually decreases with time, and a good wetting index was exhibited at the initial stage after treatment, but after several months, several tens of μN / cm It will also drop to the extent.
From the above points, a new method for improving wettability has been desired for the polylactic acid-based stretched film.

In addition, polylactic acid films generally have poor antistatic properties, so if the film is exposed to the outside, dust will adhere to the film surface and the appearance will deteriorate, for example, ink may be repelled by static electricity during printing. In some cases, so-called “printing” occurred.
As a means for solving such a problem, for example, as disclosed in Patent Document 7, a means for applying an antistatic agent to impart antistatic properties, an antistatic performance such as Patent Document 8 or Patent Document 9, and the like. The former has a problem that the performance tends to deteriorate with time, and the printing ink does not adhere to the coated surface and falls off. It also becomes a factor that the seal strength is remarkably lowered when the bag is formed. On the other hand, for the latter, it is difficult to obtain antistatic performance, so a large amount of low molecular weight additive must be blended, which not only significantly deteriorates the transparency of the film, but also the additive blows out over time. It had a problem that deteriorated the appearance of the film.
Therefore, there has been a demand for a new means for effectively increasing the antistatic property of the polylactic acid film.

Japanese Patent Laid-Open No. 2001-209039 JP 2004-34631 A JP 7-308961 A JP-A-9-111107 JP-A-6-256480 JP-A-7-207041 JP 2002-12687 Japanese Patent Laid-Open No. 9-221587 JP-A-10-36650

  In view of the above problems, an object of the present invention is to provide a new polylactic acid composition and a new polylactic acid film.

  The present invention comprises a polylactic acid polymer (A) and a polyetheresteramide polymer (B), and the ratio of the component (A) to the component (B) is 95 by mass ratio. A polylactic acid composition characterized by the ratio of 5 to 65:35 is proposed.

  In the polylactic acid-based composition of the present invention, not only the polyether ester amide exhibits antistatic performance, but when these are mixed with the polylactic acid-based composition, surprisingly, the wettability when forming a film is improved. Moreover, it has been found that the wettability of the stretched film is increased, and further, the adhesiveness and printability of the film are improved.

Therefore, the polylactic acid-based composition of the present invention can be suitably used as a raw material for films, sheets, cards, containers, and other molded articles, and can be particularly suitably used as a raw material for films.
When producing a film using the polylactic acid-based composition of the present invention, it may be a single-layered polylactic acid-based film comprising a resin layer containing the polylactic acid-based composition. It can also be set as the polylactic acid-type film which consists of a laminated structure and the outermost layer of one side or both sides consists of the resin layer containing the said polylactic acid-type composition.
And also in the polylactic acid-type film provided with either of the said structures, it can be set as the film excellent in wettability, adhesiveness, and printability. Specifically, a polylactic acid film having a wetting index of 400 to 540 μN / cm can be used, or a polylactic acid film having a logarithm LogR of the surface resistance R (Ω) of 13 or less can be used. .

  Further, using the polylactic acid composition of the present invention, a polylactic acid film comprising a laminate structure of at least three layers, and at least one of the intermediate layers is a resin layer containing the polylactic acid composition; You can also

When manufacturing a film using the polylactic acid-type composition of this invention, it can also be set as an unstretched film or a stretched film also in any said structure.
The polylactic acid film having any of the above structures can be a film having excellent moisture permeability, specifically, a polylactic acid film having a moisture permeability of 220 to 900 g / m ² · day.

  Moreover, the film manufactured using the polylactic acid-type composition of this invention is excellent in impact resistance, and especially an unstretched film becomes the thing excellent in impact resistance especially. Specifically, a polylactic acid-based unstretched film having a measured value (hydroshot value) of a dirt-type impact test of 200 to 500 N · mm can be obtained.

The upper limit value and the lower limit value of the numerical range in the present invention are included in the scope of the present invention as long as they have the same operational effects as those in the numerical range, even when slightly deviating from the numerical range specified by the present invention. It is intended to include
In addition, the term “main component” in the present specification includes the meaning of allowing other components to be contained within a range that does not interfere with the function of the main component unless otherwise specified. In particular, the content ratio of the main component is not specified, but in general, the component is a component occupying 50% by mass or more, particularly 70% by mass or more in the composition.

  A molded body (particularly a film) formed from the polylactic acid-based composition of the present invention has excellent wettability in addition to antistatic properties. Needless to say, non-stretched films, but even stretched films have excellent wettability without surface treatment, and can provide excellent adhesion and printability (particularly ink adhesion). Moreover, since the polylactic acid-based composition of the present invention contains the polyether ester amide polymer (B) in the composition, compared with the case where antistatic property and wettability are enhanced by surface treatment, The stability of the effect over time is excellent. Therefore, for example, film products that are printed on the surface of the film by various methods for the purpose of display and sales promotion effects, specifically packaging materials such as beverages, foods, chemicals, electrical appliances, miscellaneous goods, cards, etc. It can be suitably used as a plastic film used for recording materials, advertisements and displays.

  In addition, since the polylactic acid composition of the present invention and the polylactic acid film using the composition have high moisture permeability, the packaging film for fruits and vegetables, the protective material for electronic parts, particularly the polarizing sheet, It can be suitably used as a protective film for phase difference sheets, antireflection sheets and other liquid crystal members. Since protective materials for electronic parts and protective films for liquid crystal materials require antistatic properties in order to suppress damage and damage due to static electricity, this film has the antistatic properties and excellent transparency. The polylactic acid composition of the invention and the polylactic acid film using the composition are particularly excellent for use in this application.

In addition, since the unstretched film produced using the polylactic acid-based composition of the present invention is particularly excellent in impact resistance, it is used in applications requiring impact resistance, such as beverages, foods, medicines, electrical appliances, miscellaneous goods. It is particularly excellent for use in packaging or protective purposes.
Furthermore, it is suggested that the polyether ester amide has biodegradability as described in JP-T-2003-510433 and Japanese Patent No. 3425582, and the polylactic acid composition of the present invention and It can be expected that the polylactic acid film used also exhibits biodegradability.

They are sectional drawing (A) and bottom view (B) of the metal mold | die used for shaping | molding of samples 24, 25, and 26. FIG.

  First, a polylactic acid composition according to an embodiment of the present invention will be described, but the polylactic acid composition of the present invention is not limited to the following embodiment.

(Polylactic acid composition)
The polylactic acid-based composition according to the present embodiment includes a polylactic acid-based polymer (A), a polyetheresteramide polymer (B), and / or a predetermined block polymer (C) as main components. It is a polylactic acid composition. That is, it is a polylactic acid-based composition mainly comprising the components (A) and (B), a polylactic acid-based composition mainly comprising the components (A) and (C), or the A polylactic acid-based composition comprising components (A), (B) and (C) as main components.
The “main component” in this case includes the meaning of allowing the inclusion of components other than the components (A), (B), and (C). The total content of the components (A), (B), and (C) is not particularly limited as long as the functions of these components are not hindered. It is preferable to occupy 70% by mass or more, particularly 90% by mass or more.

(Polylactic acid polymer (A))
The polylactic acid polymer (A) used in the present embodiment is a polymer formed by condensation polymerization of a monomer containing lactic acid as a main component.

The polylactic acid polymer (A) used in this embodiment includes poly (L-lactic acid) whose structural unit is L-lactic acid, poly (D-lactic acid) whose structural unit is D-lactic acid, and whose structural unit is L. -Poly (DL-lactic acid) composed of both lactic acid and D-lactic acid, or a mixture composed of a combination of two or more of these.
Lactic acid has two types of optical isomers, namely L-lactic acid and D-lactic acid, and the crystallinity differs depending on the ratio of these two types of structural units. For example, a random copolymer having a ratio of L-lactic acid to D-lactic acid of about 80:20 to 20:80 has a low crystallinity, and becomes a transparent complete amorphous polymer that softens near a glass transition point of 60 ° C. On the other hand, a random copolymer having a ratio of L-lactic acid to D-lactic acid of about 100: 0 to 80:20 or about 20:80 to 0: 100 has a glass transition point of 60 as in the case of the copolymer described above. Although it is about ° C., the crystallinity is high. The degree of crystallinity is determined by the ratio of L-lactic acid and D-lactic acid described above, and after melt extrusion, if it is immediately cooled, it becomes an amorphous material with excellent transparency, and if it is slowly cooled, it becomes a crystalline material. It becomes. For example, a homopolymer consisting only of L-lactic acid or a homopolymer consisting only of D-lactic acid is a semicrystalline polymer having a melting point of 180 ° C. or higher (: crystalline or amorphous at room temperature depending on the treatment) Polymer.).

  Among these, as the polylactic acid polymer (A) as a film raw material, it is preferable to select polylactic acid that is easier to crystallize because it is preferable to improve the crystallinity by heat treatment during film production or after production. From this viewpoint, a polylactic acid-based polymer composed of a random copolymer in which the ratio of L-lactic acid to D-lactic acid is 100: 0 to 94: 6 or 6:94 to 0: 100 is preferable, particularly 99.5: It is more preferable to use a polylactic acid polymer having a ratio of 0.5 to 97: 3 or 3:97 to 0.5: 99.5.

The polylactic acid polymer (A) can also be a copolymer of lactic acid and other hydroxycarboxylic acids.
At this time, as "other hydroxycarboxylic acid units" to be copolymerized, glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxy-n-butyric acid, 2-hydroxy-3,3-dimethylbutyric acid, Examples thereof include bifunctional aliphatic hydroxycarboxylic acids such as 2-hydroxy-3-methylbutyric acid, 2-methyllactic acid, and 2-hydroxycaproic acid, and lactones such as caprolactone, butyrolactone, and valerolactone.

  The polylactic acid-based polymer (A) used in the present embodiment is a non-fatty compound such as a non-aliphatic carboxylic acid such as terephthalic acid and / or an ethylene oxide adduct of bisphenol A as a small amount copolymerization component, if necessary. Group diol, lactic acid and / or hydroxycarboxylic acid other than lactic acid may be contained.

As a polymerization method for producing the polylactic acid polymer (A), a condensation polymerization method, a ring-opening polymerization method, and other known polymerization methods can be employed. For example, in the condensation polymerization method, polylactic acid having a desired composition can be obtained by directly dehydrating condensation polymerization of L-lactic acid, D-lactic acid or a mixture thereof.
In the ring-opening polymerization method (lactide method), polylactic acid can be obtained by using a selected catalyst while using lactide, which is a cyclic dimer of lactic acid, with a polymerization regulator or the like as necessary. .

  The preferred range of the weight average molecular weight of the polylactic acid polymer (A) is 60,000 to 700,000, more preferably 80,000 to 400,000, and more preferably 100,000 to 300,000. If the weight average molecular weight is 60,000 to 700,000, the molecular weight will not be too small, and practical physical properties will not be impaired in terms of mechanical properties and heat resistance. Further, since the molecular weight is not too high, the melt viscosity is not too high and the molding processability is not inferior.

(Polyether ester amide polymer (B))
Next, the polyether ester amide polymer (B) will be described.

  The polyether ester amide polymer (B) used in the present embodiment is a block copolymer represented by the following general chemical formula (1) in which a polyamide block and a polyether block are linked by an amide bond and an ester bond. It is. Incidentally, it is possible to produce a film even with this polyether ester amide polymer (B) alone.

R ₁ and R ₂ in the general chemical formula (1) are each a C2 to C12 saturated aliphatic hydrocarbon, including the case where R1 = R2. The “polyamide structure (: polyamide block)” represented by the repeating unit of n in the formula can be obtained from ring-opening polymerization of lactam or polycondensation of derivatives thereof, and can also be obtained by condensation of diamine and dicarboxylic acid or derivatives thereof. It is a polyamide oligomer (p) that can also be obtained from polymerization, and the polyamide oligomer (p) has a number average molecular weight of 400 to 10,000.
In the formula, R ₁ and R ₂ are shown as being a single diamine and a single dicarboxylic acid, but may be cocondensation polymerization in which two or more are mixed.

R ₄ in the general chemical formula (1) is a C2 to C12 (C: carbon number) aliphatic or aromatic hydrocarbon, and is represented by a repeating unit of m in the formula “polyether structure (: polyether Is a polyether oligomer (q) having a number average molecular weight of 400 to 10,000 of C2 polyethylene glycol or C3 polypropylene glycol from the viewpoint of improving wettability and conductivity.
In the formula, it is shown as a single polyether, but it may be a polymer comprising two or more components.

R ₃ in the general chemical formula (1) is a C2 to C12 aliphatic or aromatic hydrocarbon, and has a structure in which both ends are carboxylic acids or derivatives thereof. Specific examples include succinic acid or a derivative thereof in which R ₃ is C2, adipic acid or a derivative thereof in which C4 is used, and aromatic compounds such as terephthalic acid or a derivative thereof, naphthalic acid or a derivative thereof, and bisphenol or a derivative thereof. There is. This component is obtained by condensing the polyamide oligomer (p) and the polyether oligomer (q) so as to be an amide bond and an ester bond, respectively, and increasing the molecular weight.

The polyether ester amide polymer (B) exhibits a function as an impact resistance improver by being mixed in the polylactic acid composition as a thermoplastic elastomer. The polyether ester amide polymer (B) has a high hydrogen bonding property, and has a polyamide component called “hard segment” having a strong bond within the molecule and between the molecules, and a bonding force between the molecules and between the molecules. Polyether ester amide polymer (B) having a polyether component called “soft segment” which is low and has a high ether bond removability, and has such a hard segment / soft segment structure. Acts as an impact modifier by mixing it with other polymers as a thermoplastic elastomer.
In addition, the polyether ester amide polymer (B) is also excellent in conductivity, and functions as an antistatic agent when mixed with the polylactic acid composition. In addition, an ionic substance can be introduce | transduced in a polyetheresteramide polymer, and also a conductive performance can be improved.
In addition, the polyether ester amide polymer (B) is mixed with the polylactic acid polymer (A) to exert the effect of improving the wettability at the time of film forming, and the adhesion of the film without surface treatment. Ink adhesion can be improved.

Among the polyetheresteramide polymers (B), a polyetheresteramide polymer having a refractive index of 1.40 to 1.50, more preferably 1.41 to 1.49 is selected and used. Therefore, remarkably excellent transparency can be obtained.
If the refractive index of the polyether ester amide mixed with the polylactic acid polymer (A) is in the range of 1.40 to 1.50, the haze of the film is at least a normal 10 to 100 μm thick film. It will be less than 10%, and there will be no apparent opacity. Further, if a polyether ester amide polymer having a refractive index of 1.41 to 1.49 is used, the haze of the film can be reduced to 6% or less.

  The molecular weight of the polyether ester amide polymer (B) is preferably 10,000 to 300,000, particularly 20,000 to 200,000 in terms of mass average.

(Block polymer (C))
Next, the block polymer (C) will be described.

The block polymer (C) used in the present embodiment is a block polymer having a structure in which a polyolefin block and a polymer block having a polyoxyethylene chain are alternately and repeatedly bonded.
The bond between the polyolefin block and the polymer block having a polyoxyethylene chain may be at least one bond selected from the group consisting of an ester bond, an amide bond, an ether bond and an imide bond.

Specific examples of the block polymer (C) include block polymers disclosed in paragraphs [0007] and [0021] to [0064] of JP-A No. 2004-217929, that is, blocks of polyolefin (a), and volume resistivity. Is preferably a block polymer (A2) having a structure in which a block of a polymer (b) having a polyoxyethylene chain of 1 × 10 ⁵ to 1 × 10 ¹¹ Ω · cm is repeatedly bonded alternately. The polyolefin (a) block and the polyoxyethylene chain-containing polymer (b) block are repeated via at least one bond selected from the group consisting of an ester bond, an amide bond, an ether bond and an imide bond. It has an alternating structure and has a repeating unit represented by the following general formula (2). Polymers can be preferably used that. For example, trade names: Pelestat 300, Pelestat 303 (both manufactured by Sanyo Chemical Co., Ltd.) are suitable examples.

In the formula (2), n is an integer of 2 to 50 (preferably 3 to 40, more preferably 4 to 30, particularly preferably 5 to 25); ^one of R ¹ and R ² is H and the other is H or methyl group; y is from 15 to 800 (preferably 20 to 500, more preferably 30 to 400) an integer; E ¹ is the residue minus the hydroxyl groups from diol (b01) or the dihydric phenol (bO2); a ¹ is An ethylene group, or an alkylene group having 2 to 4 carbon atoms which essentially contains an ethylene group; m and m ′ are integers of 1 to 300 (preferably 5 to 200, more preferably 8 to 150); X and X ′ are When a group selected from the following general formulas (3) and (4) and the corresponding (3 ′) and (4 ′), that is, X is a group represented by the general formula (3), X ′ is a general formula (3 It is a group represented by '), and the same relationship applies to general formulas (4) and (4') A.

In the general formulas (3) and (4) and the corresponding (3 ′) and (4 ′) formulas, R is H or an alkyl group having 1 to 4 carbon atoms (preferably 1 or 2), and R ³ is carbon number A divalent hydrocarbon group of 1 to 11 (preferably 2 to 11, more preferably 5 to 11), R ⁴ is H or a carbon number of 1 to 10 (preferably 1 to 8, more preferably 1 to 6); Alkyl group; r is an integer of 1-20 (preferably 1-15, more preferably 1-10), u is 0 or 1; Q, Q ′, T and T ′ are groups represented by the following formulae.

In the general formulas (5) and (6) and the corresponding (5 ′) and (6 ′), R ⁵ is H or 1 to 10 carbon atoms (preferably 1 to 8, more preferably 1 to 6). ), R ⁶ is H or a methyl group, t is 1 when R ⁶ is a methyl group, and 0 when H is H.

Polyether segments in {} in the repeating units of ^{{(OA 1) mO-E} 1 -O (A 1 O) m '} is represented by the general formula (2), polyether diols (b1) or polyether diamine This is a structure derived from (b2), and E ¹ , A ¹ , m and m ′ in the formula are the same as described above.

  In the general formula (2), a block polymer in which X is a group represented by the general formula (3) and X ′ is a group represented by the general formula (3 ′) includes polyolefin (a211) and / or Alternatively, polymerization reaction of (A21) obtained by polymerizing polyolefin (a212) and polyether diol (b1), and polyolefin (a211) and / or polyolefin (a212) and polyetherdiamine (b2). (A22) obtained by the above.

The polyolefin (a211) is preferably both polyolefins (a20) having a polyolefin whose both ends can be modified as a main component (content 50% by weight or more, more preferably 75% by weight or more, particularly preferably 80 to 100% by weight). A structure in which the terminal is modified with α, β-unsaturated carboxylic acid (anhydride) (α, β-unsaturated carboxylic acid, an alkyl ester having 1 to 4 carbon atoms or an anhydride thereof, the same applies hereinafter). It is polyolefin which has.
The polyolefin (a212) is a polyolefin having a structure obtained by secondary modification of the polyolefin (a211) with a lactam or an aminocarboxylic acid.

  (A21) is a combination of polyolefin (a211) and polyether diol (b1) (A211), a combination of polyolefin (a212) and polyetherdiol (b1) (A212), and (A211). ) And (A212). Similarly, (A22) is a combination of polyolefin (a211) and polyetherdiamine (b2) (A221), a combination of polyolefin (a212) and polyetherdiamine (b2) (A222), and (A221). ) And (A222).

  In the general formula (2), a block polymer in which X is a group represented by the general formula (4) and X ′ is a group represented by the general formula (4 ′) includes a polyolefin (a213) (r = 1) and / or polyolefin (a214) (when r ≧ 2) and polyether diol (b1) are polymerized (A23), polyolefin (a213) and / or polyolefin (a214) ) And polyether diamine (b2) (A24) obtained by polymerization reaction.

The polyolefin (a213) is an oxidized polyolefin (a20) having a polyolefin that can be modified at both ends, preferably a main component (content of 50% by weight or more, more preferably 75% by weight or more, particularly preferably 80 to 100% by weight). Alternatively, it is a polyolefin having a hydroformylation-modified structure.
The polyolefin (a214) is a polyolefin having a structure obtained by secondary modification of the polyolefin (a213) with lactam or aminocarboxylic acid.

  In addition, (A23) is a combination of polyolefin (a213) and polyether diol (b1) (A231), a combination of polyolefin (a214) and polyether diol (b1) (A232), and (A231). ) And (A232). Similarly, (A24) is a combination of polyolefin (a213) and polyetherdiamine (b2) (A241), a combination of polyolefin (a214) and polyetherdiamine (b2) (A242), and (A24), A mixture of A241) and (A242) is included.

  The amount of the polymer (b) having a polyoxyethylene chain constituting the block polymer (A2) is preferably from the viewpoint of antistatic properties, the block of the polyolefin (a) and the polymer (b) having a polyoxyethylene chain. It is 20 to 90% by weight, more preferably 25 to 80% by weight, and particularly preferably 30 to 70% by weight based on the total weight with the block.

  The Mn of the block polymer (A2) is preferably from 2,000 to 60,000, more preferably from 5,000 to 40,000, particularly preferably from 8,000 to 30,000, from the viewpoint of antistatic properties.

  In the structure (A2), the average number of repeating units (Nn) of the block of the polyolefin (a) and the block of the polymer (b) having a polyoxyethylene chain is preferably 2 from the viewpoint of antistatic properties. To 50, more preferably 2.3 to 30, particularly preferably 2.7 to 20, and most preferably 3 to 10.

  The terminal of (A2) is a carbonyl group derived from the polyolefin (a), an amino group and / or an unmodified polyolefin terminal (polyolefin terminal not modified at all, that is, an alkyl group or an alkenyl group), or a polyoxyethylene chain. It is either a hydroxyl group and / or an amino group derived from the polymer (b). Among these, a carbonyl group, an amino group, and a hydroxyl group are preferable as a terminal from the viewpoint of reactivity, and a carbonyl group and a hydroxyl group are more preferable.

Among the block polymers (C) described above, the refractive index is 0.05 or less, more preferably 0.04 or less, in other words, the refractive index is 1.40. By selecting and using a block polymer in the range of ˜1.50, more preferably in the range of 1.41 to 1.49, outstanding transparency can be obtained.
If the refractive index of the block polymer mixed with the polylactic acid polymer (A) is in the range of 1.40 to 1.50, the haze of the film is less than 10% in the case of at least a normal film having a thickness of 10 to 100 μm. And there will be no unclear appearance. Furthermore, if a block polymer having a refractive index of 1.41 to 1.49 is used, the haze of the film can be reduced to 6% or less.

(Combination ratio of each component)
The blending ratio of each component in the polylactic acid-based composition of the present embodiment is such that the polylactic acid-based polymer (A), the polyether ester amide polymer (B) and / or the predetermined block polymer (C) (component (B ) And the component (C), it is important that the total amount of both, the same shall apply hereinafter) is 95: 5 to 65:35 by mass ratio, and a preferred range is by mass ratio. 90:10 to 70:30.
If the blending ratio of the polyether ester amide polymer (B) and / or the block polymer (C) is 5% or more, the wetting index will be 400 μN / cm or more, and films with excellent adhesion and ink adhesion will be produced. can do. On the other hand, if it is 35% or less, it will not be impossible to stretch due to its crystallinity. Moreover, when comprising a laminated | multilayer film using the polylactic acid-type composition of this embodiment, for example, a polyetheresteramide polymer (B) and / or block polymer (C) are used for a surface layer, a back layer, or a front and back layer. When using a polylactic acid-based composition containing significantly exceeding 35%, it is possible to stretch if each layer is formed thin, but still flow unevenness occurs during extrusion take-off, resulting in a film with poor appearance. May be obtained. Moreover, since the blocking of the films tends to occur when the polarity of the film surface increases, it is important that the mixing ratio of the polyetheresteramide (B) and / or the block polymer (C) is 35% or less in this sense. is there.

Further, taking the antistatic property into consideration, the mixing ratio of the polylactic acid polymer (A) to the polyether ester amide polymer (B) and / or the block polymer (C) is 90:10 to 65 by mass ratio. : 35 is preferable, and a more preferable range is 85:15 to 70:30 in terms of mass ratio. If the polyether ester amide polymer (B) and / or block polymer (C) is 10% or more, the logarithm LogR of the surface resistance R (Ω) is 13 or less, effectively suppressing the generation of static electricity during processing. can do. On the other hand, if it exceeds 35%, blocking between films and the like occur, and therefore it is preferably 35% or less.
In this case, since it is from the viewpoint of antistatic properties, when forming a laminated film, the mixing ratio of the polylactic acid-based composition in the outermost layer on at least one side is 90:10 to 65:35 in mass ratio. This is very important.

In the case of forming an unstretched film, from the viewpoint of improving impact resistance, a mixture of a polylactic acid polymer (A) and a polyether ester amide polymer (B) and / or a block polymer (C) is used. The ratio is preferably 90:10 to 65:35 by mass ratio.
Polylactic acid-based polymers are generally inferior in impact resistance, and impact resistance is improved when oriented by biaxial stretching, but it is necessary to improve impact resistance by some method when not oriented. . Therefore, in order for the polyether ester amide polymer (B) and / or the block polymer (C) to function as an impact resistance improver, the mixing ratio of the component (B) and / or the component (C) is expressed by mass ratio. 10% or more is preferable. When component (B) and / or component (C) is less than 10%, impact resistance using a hydro-shot high-speed impact tester HTM-1 type (manufactured by Shimadzu Corporation), which is a dirt-type impact tester, is obtained. When evaluated, the fracture energy becomes less than 200 N · m, and the utility is poor. In order to provide more practical utility, impact resistance of 300 N · m or more is required, so the blending ratio of component (B) and / or component (C) is preferably 15% or more. On the other hand, if it exceeds 35%, blocking between films occurs as described above, which is not preferable.
In the case of a laminated film, the ratio averaged over all layers is preferably in the above range, and if it is in the above range through all layers, it may be blended only in any layer of the laminated structure, for example, intermediate You may mix only in the layer.

  In addition, the film which biaxially stretched and heat-treated the sheet | seat which consists only of a polylactic acid-type polymer (A), and the corona treatment is wet compared with the non-stretched non-crystalline film and the corona treatment of the same density. The index will be below. This is because the former has a higher degree of crystallinity. However, when the polyether ester amide polymer (B) and / or the block polymer (C) is blended with the polylactic acid polymer (A), the biaxially stretched film has a specific wettability index. Features appear. The reason for this is not clear, but since the stretching behavior of polylactic acid during stretching and the stretching behavior of components (B) and (C) are different, components (B) and (C) are projected on the film surface, and the components (B B) It is considered that this is because the area occupied by the surface layer of (C) increases as compared with the unstretched film.

(Other ingredients)
In addition to the components (A), (B), and (C), the polylactic acid-based composition of the present embodiment includes a heat stabilizer, a light stabilizer, a light absorber, a lubricant, a plasticizer, Inorganic fillers, colorants, pigments and the like can be added.
In addition, for the purpose of improving the slipperiness and flexibility of the film, the aliphatic polyester or aliphatic / aromatic polyester homopolymer raised as a copolymer component with the polylactic acid described above may be mixed. It doesn't matter. These polymers have a weight average molecular weight of about 20,000 to 300,000.

(Molding example)
Next, as an example of a molded product using the polylactic acid-based composition of the present embodiment, a polylactic acid-based film using the polylactic acid-based composition of the above embodiment will be described. However, the molded article using the polylactic acid-based composition of the present invention is not limited to the film described below.

(Single layer film)
Using the polylactic acid-based composition of the present embodiment, a single-layer polylactic acid-based film consisting only of a resin layer containing the polylactic acid-based composition as a main component can be produced. At this time, the thickness of the polylactic acid film having a single layer structure is preferably 5 μm to 1 mm, particularly 10 μm to 800 μm, and more preferably 15 μm to 500 μm.

(Laminated film)
Moreover, the polylactic acid-type film of a laminated structure can also be manufactured using the polylactic acid-type composition of the said embodiment. For example, it can be set as the laminated structure which consists of at least 2 layers, and can form the outermost layer of one side or both sides from the resin layer which contains the polylactic acid-type composition of the said embodiment as a main component.
Here, the resin layer containing the polylactic acid-based polymer (A) as a main component is expressed as an X layer, and the polylactic acid-based composition of the above embodiment (: component (A), component (B) and / or component) When the resin layer having (C) mixed at a predetermined ratio) as a main component is expressed as a Y layer, from the viewpoint of improving the wetting index and / or the antistatic performance, a laminated structure having the Y layer as the outermost layer is obtained. preferable. For example, a Y / X / Y three-layer structure, a Y / X / Y / X / Y five-layer structure, and other multilayer structures such as Y / X / Y / X /.../ Y Can be mentioned.
Moreover, when manufacturing by adjusting the thickness of each layer etc. so that a film may not curl, the laminated structure which uses only one side as a Y layer (functional layer) is preferable. For example, a two-layer structure composed of Y / X, a four-layer structure such as Y / X / Y / X, and another multilayer structure such as Y / X /. You can also.
In the above laminated structure, the stacking order of X and Y may be reversed.
The thickness of the Y layer constituting the outermost layer is 1 μm or more, preferably 3 μm or more, more preferably 4 μm or more, and particularly preferably 4 μm to 50 μm.

Moreover, it can also be set as the laminated structure which consists of at least 3 layers, and can also be set as the polylactic acid-type film formed from the resin layer which has the polylactic acid-type composition of the said embodiment as a main component at least one layer among intermediate | middle layers. .
Here, the resin layer containing the polylactic acid polymer (A) as a main component is expressed as an X layer, and the polylactic acid composition (component (A) and component (B) and / or component (C) of the above embodiment is used. ) In a predetermined ratio) is expressed as a Y layer. For example, X / Y / Y / X, X / A four-layer structure such as Y / X / Y or other multilayer structures such as X / Y / X / Y /.
However, the stacking order of X and Y in the stacked structure may be reversed.
The thickness of the Y layer constituting at least one of the intermediate layers is 5 μm or more, preferably 10 μm or more, more preferably 15 μm or more, and particularly preferably 20 to 800 μm.

  In the polylactic acid-based film having the above-described configuration, the “main component” includes the intention to allow components other than the polylactic acid-based composition to be included as a component of each resin layer. The content of the polylactic acid-based composition is not particularly limited as long as it does not interfere with the function of the polylactic acid-based composition, but is 50% by mass or more, particularly 70% by mass or more, particularly 90% by mass in the above resin layers. It is preferable to occupy the above.

In the polylactic acid film having the above configuration, the thickness of the laminated film is 10 to 800 μm as a whole, preferably 15 to 500 μm, and more preferably 20 to 400 μm.
In addition, a film usually may be referred to as less than 100 μm in a narrow sense, and may be referred to as a sheet above 100 μm. However, it is not clearly defined in practice. In this paper, all sheets of 100 μm or more are also films.
In addition, the thickness of the adhesive layer, the adhesive resin layer, the recycled resin layer, or the X layer and the Y layer having a thickness of 10 μm or less, preferably 5 μm or less, between the respective layers between X / Y within a range not impairing the effects of the present invention. An intermediate layer may be laminated.

(Modifier)
In each layer of the polylactic acid-based film having the above configuration, various modifications such as a heat stabilizer, a light stabilizer, a light absorber, a lubricant, a plasticizer, an inorganic filler, a colorant, and a pigment are provided for the purpose of adjusting various physical properties. An agent may be added.
Examples of the inorganic filler include silica, talc, calcium carbonate, barium sulfate, mica, kaolin, and clay. Moreover, titanium oxide is mentioned as a pigment. Titanium oxide is used for white and is often blended in order to obtain concealability. There are anatase type and rutile type as the type of titanium oxide to be used. Both can be used, but the surface of titanium oxide is a photochemically active substance. If light resistance is considered, the latter or surface treatment It is preferred to use what has been deactivated. In addition, the white sheet | seat which mix | blended titanium oxide is useful as a synthetic paper, a card | curd, and a recording material.
The inorganic filler is preferably blended in an amount of 1 to 35 parts by mass, more preferably 5 to 20 parts by mass with respect to 100 parts by mass of the polylactic acid polymer (A).

(Characteristics of film)
The shrinkage rate of the polylactic acid-based film of this embodiment, particularly the polylactic acid-based biaxially stretched film, is 10% or less, more preferably 7% or less, particularly 0.1 to 5% after 120 ° C./5 minutes of hot air. Preferably there is. This is because if it exceeds 10%, it may be a factor that seriously impairs the appearance of the film such as wrinkles and undulations.

With respect to the moisture permeability of the film, the moisture permeability when evaluated by the JISZ0208B method can be in the range of 220 to 900 g / m ² · day, and is preferably in this range. If it is less than 200 g / m ² · day, it is not useful as a protective film for an electronic member, particularly a liquid crystal module or an optical film used therein, and uneven brightness and color unevenness may occur after bonding. . On the other hand, if it exceeds 900 g / m ² · day, the moisture permeability of the film is too high and the film itself absorbs a considerable amount of moisture, so that the dimensional change of the film becomes remarkable, and undulation or the like tends to occur.
In order to increase the moisture permeability of the film to the above range, whether it is a single layer film or a laminated film, the polyether polyesteramide polymer (B) and / or the block with respect to 100 parts by mass of the entire film The polymer (C) is preferably contained in an amount of 10 to 35 parts by mass, preferably 15 to 30 parts by mass. If the polyether polyesteramide polymer (B) and / or the block polymer (C) is contained in an amount of 10 to 35 parts by mass with respect to 100 parts by mass of the whole film, the moisture permeability when evaluated by the JISZ0208B method is 220 to 220. It can be in the range of 900 g / m ² · day.

The film surface wetness index is preferably 400 to 540 μN / cm, and more preferably 420 to 520 μN / cm.
In order to adjust the wetting index of the film within the range, the outermost layer on one side or both sides of the single-layer configuration or the laminated configuration contains the polylactic acid-based composition of the present embodiment as a main component. What is necessary is just to form from the resin layer to do.

Regarding the logarithm LogR of the surface resistance R (Ω) of the film surface, it is preferably 13 or less, particularly preferably 10 to 12.
As for the impact resistance of the film, the measured value (hydroshot value) of the dirt type impact test is preferably 200 to 500 N · mm, particularly 250 to 450 N · mm.

(Film production method)
Next, as an example of a method for producing a polylactic acid film according to this embodiment, a method for producing a polylactic acid biaxially stretched film will be described.
In addition, about the manufacturing method of a non-stretched film and uniaxial stretching, it can manufacture in consideration of the manufacturing method of the polylactic acid-type biaxially stretched film demonstrated below.

  As a lamination method, a currently known method can be appropriately employed. For example, a method of co-extrusion that connects a plurality of extruders to a single die in a feed block type or a multi-manifold type, another type of film is heat-pressed on the surface of the unrolled mixed film using a roll or a press plate The method etc. can be mentioned.

After a sheet or cylinder extruded from a T die, I die, round die or the like is rapidly cooled by a cooling cast roll, water, compressed air or the like and solidified in a state close to an amorphous state, a roll method, a tenter method, What is necessary is just to extend | stretch in a biaxial direction by the tubular method etc.
In the production of a biaxially stretched film, a roll method is used for longitudinal stretching and a sequential biaxial stretching method that employs a tenter method for transverse stretching, or a simultaneous biaxial stretching method in which stretching is performed by the tenter method simultaneously in the longitudinal and transverse directions. Use it.

As stretching conditions, a stretching temperature of 55 to 90 ° C., preferably 65 to 80 ° C., a longitudinal stretching ratio of 1.5 to 5 times, preferably 2 to 4 times, and a transverse stretching ratio of 1.5 to 5 times, preferably 2 ˜4 times, stretching speed of 10 to 100,000% / min, preferably 100 to 10,000% / min.
However, these suitability ranges vary depending on the composition of the polymer and the heat history of the unstretched sheet, and therefore it is preferable to appropriately determine the strength and elongation of the film.
If any of the longitudinal and lateral stretching ratios is significantly out of the range of 1.5 to 5 times, or the stretching temperature is significantly out of 55 to 95 ° C., the thickness accuracy of the resulting film will be significantly reduced. In particular, this tendency is remarkable in a film that is heat-treated after stretching. Such thickness fluctuation is a factor that reduces the appearance of products such as wrinkles and undulations in printing, or in secondary processing such as lamination with other films, metal thin films, paper, and bag making. So be careful.

  When it is desired to suppress the thermal shrinkage of the film, it is preferable to heat-treat in a state where the film is held after stretching. Usually, in the tenter method, since the film is stretched in a state where the film is held by a clip, it is immediately heat-treated. In the film secondary processing step, problems such as shrinkage of the film during processing are likely to occur.

  The polylactic acid film according to the present embodiment can be laminated, coated, etc. without any pretreatment, but may be surface treated if necessary. Examples of the surface treatment at this time include physical roughening (unevenness) treatment or oxidation treatment. Examples of the roughening treatment include sand blast treatment and hairline processing treatment. Examples of the oxidation treatment include corona treatment, plasma treatment, ozone / ultraviolet treatment, chromic acid treatment, and flame treatment. In addition, there is organic solvent treatment. There is also a method of roughening the surface of the film by eroding the film surface by adjusting the good solvent and the poor solvent by utilizing the difference in solvent resistance depending on the crystallinity of the polylactic acid polymer. Good solvents include toluene, ethyl acetate, THF, MEK, DMF, and the like, and poor solvents include methanol, ethanol, isopropyl alcohol, hexane, and the like.

(Use of film)
The polylactic acid film according to this embodiment is printed on the film surface, packaging materials such as bags and cases for beverages, foods, medicines, electrical appliances, miscellaneous goods, etc., recorded materials such as cards, sales promotion / advertisement / It can be suitably used as a display sheet. Specific examples include print sheets for display of game machines such as pachinko machines, slot machines, and game machines, print sheets for advertisements used in vending machines, display tags used at retail stores, and tags for flower arrangements. Can be used for election posters, etc.
In addition, since the polylactic acid film according to this embodiment is excellent in transparency, moisture permeability, and anti-static property, it can be preferably used as a protective film for various electronic components, particularly optical sheets and liquid crystal modules.
The unstretched film is also useful as a thermoformed sheet.

  The various samples and their physical property evaluations are shown below, but the present invention is not limited by these.

(1) Stability of take-up The film was swung out from the die and investigated for width fluctuation when taken up with a cast roll. The base used has a lip width of 550 mm and a lip gap of about 2 mm. The take-up speed was adjusted within a range of 10 to 20 m / min.
When the width of the sheet taken up fluctuated by 10 mm or more, it was poor, and when it was less than 10 mm, it was good and evaluated as “good”.

(2) Thickness Measured by contacting the film using a dial gauge.

(3) Surface resistivity measurement Measurement was performed based on JIS C 2151. Three points on the inner surface and three points on the outer surface of the wound film were measured, and the average value thereof was calculated.

(4) Wetting index It measured based on JISC6768. Measurement was arbitrarily performed three times from the inner center of the wound film, and the wetting index was determined.

(5) Ink adhesion The film was cut into A3 size, and about 0.5 cc of gravure ink shown below was dropped on the film with a spoid, and immediately developed and applied with a Mayer bar (No. 4). Next, the coated film was dried in an oven set at 40 ± 3 ° C. for about 30 seconds. The ink adhesion was obtained by attaching a serotape (Elpac LP-18, manufactured by Nichiban Co., Ltd.) to the printed surface and rubbing with a finger 5 times from the top of the serotape (registered trademark). Immediately thereafter, the serotape was peeled off at once, and the amount of the ink peeled was visually observed. The evaluation was based on a five-point evaluation, with 5 indicating no ink separation and 1 indicating complete separation.
= Ink for evaluation =
PANN color S39 indigo (manufactured by Toyo Ink Manufacturing Co., Ltd.)

(6) Blocking resistance Two films were cut into 40 mm × 50 mm, and the surfaces corresponding to the printed layers were overlapped. Further, a mirror surface plate of about 40 mm × 50 mm was superposed on the top and bottom, and placed in a constant temperature and humidity chamber. A weight of about 5 kg was placed on the mirror plate and left standing. The test temperature and humidity were set to 50 ° C./80% RH. Two days later, the peeled state of the laminated film was observed.
Films stuck to each other and difficult to peel off were evaluated as poor, and those excellent in peeling were evaluated as good.

(7) Impact resistance Impact resistance was evaluated using a Hydroshot R high-speed impact tester HTM-1 type (manufactured by Shimadzu Corporation) which is a dirt type impact tester. The film was cut out to approximately 100 mm × 100 mm, the test piece was fixed to the clamp of the tester, a weight was dropped on the center of the film to give an impact, and the energy when the test piece was broken was read. The measurement temperature is 23 ° C, and the falling speed of the falling weight is 3 m / sec. The lower the energy at the time of film destruction, the lower the impact resistance.

(8) Moisture permeability The film was measured based on the JISZ0208B method.

(9) Evaluation of brightness unevenness An adhesive processed polarizing plate (NWF SEG1425WVARC150K, manufactured by Nitto Denko) is attached to a glass plate, and a surface protective film is placed on the area of about half the polarizing plate. Was attached and fixed twice with an OPP tape (Mitsubishi Resin Diahalo Tape) so as to prevent moisture from entering from the outer periphery, thereby preparing an evaluation sample. This evaluation sample was put into a constant temperature and humidity machine of 35 ° C. and 80% RH, stored for 10 hours, taken out, and brought to room temperature.

The fixing tape and the surface protective film were peeled off. Next, a light was turned on from the bottom of the glass plate, and a straight Nicole state was obtained with another polarizing plate (NPFHEG1425DU manufactured by Nitto Denko).
Observed visually from above and from various angles, and the case where there is no difference in brightness between the portion where the surface protective film was not bonded and the portion where the surface protective film was bonded is good (Mura) ) Was evaluated as x.

(Sample 1)
As a resin component, a random copolymer having a structural unit of L-lactic acid: D-lactic acid = 98.5: 1.5, a polylactic acid polymer having a glass transition point (Tg) of 58 ° C. (trade name: NatureWorks 4032D, manufactured by Cargill Dow, USA, molecular weight of about 200,000, refractive index of 1.45) 80% by mass, and polyether ester amide (trade name: Pelestat NC7530, manufactured by Sanyo Chemical Co., Ltd., refractive index of 1.53) 20 mass % And mixed with 100 parts by mass of polylactic acid in a total of 0.05 parts by mass of dried granular silica having an average particle size of 1.4 μm (trade name: Siricia 100, manufactured by Fuji Silysia Chemical Co., Ltd.). It extrude | squeezed from the nozzle | cap | die at 210 degreeC with the 75 mm diameter same direction twin screw extruder at 210 degreeC.
And this extrusion sheet | seat was quenched with the casting roll of about 35 degreeC, and the unstretched film was obtained.
Subsequently, using a biaxial stretching apparatus, the film is stretched 2.8 times while being heated to 75 ° C. with a roll and an infrared heater in the longitudinal direction, then set to a preheating zone temperature of 72 ° C. with a tenter in the width direction, and the temperature of the stretching zone is 76 The film was stretched 3.2 times at a setting of ° C. The temperature of the heat treatment zone in the tenter was 140 ° C., and a heat-treated biaxially stretched film was produced. The amount of molten resin discharged from the extruder and the line speed were adjusted so that the film thickness was approximately 40 μm on average.
The evaluation results of the film are shown in Table 1.

(Sample 2)
A biaxially stretched film having a thickness of 40 μm was produced in the same manner as Sample 1, except that the polyether ester amide was changed to the trade name Perestat NC6321 (manufactured by Sanyo Chemical Co., Ltd., refractive index 1.51).
The evaluation results of the film are shown in Table 1.

(Sample 3)
In the same manner as Sample 2, an unstretched sheet having a thickness of 300 μm was produced by extrusion.
The evaluation results of this film are shown in Table 1.

(Sample 4)
Instead of polyetheresteramide, a block polymer having a structure in which a polyolefin block and a polymer block having a polyoxyethylene chain are alternately bonded repeatedly (referred to as “polyolefin / polyoxyethylene block polymer”). A biaxially stretched film having a thickness of 40 μm was produced in the same manner as Sample 1, except that the trade name Perestat 303 (manufactured by Sanyo Chemical Co., Ltd., refractive index 1.49) was used.
The evaluation results of the film are shown in Table 1.

(Samples 5 and 6)
As a resin component, a polylactic acid-based polymer (trade name: NatureWorks 4032D, manufactured by Cargill Dow, USA), and a trade name, Perestat 300, which is a polyolefin / polyoxyethylene block polymer (manufactured by Sanyo Chemical Co., Ltd., refractive index 1.49) Are mixed in a mass ratio of 95: 5 and a total of 100 parts by mass of polylactic acid is dried into a granular silica having an average particle size of 1.4 μm (trade name: Siricia 100, manufactured by Fuji Silysia Chemical Co., Ltd.) 0.05 part by mass was mixed and extruded as a front and back layer from a multi-manifold die at 210 ° C. while degassing with a 58 mmφ co-directional twin screw extruder.
Further, the polylactic acid polymer having a structural unit of L-lactic acid: D-lactic acid = 98.5: 1.5 was extruded as an intermediate layer from the die at 210 ° C. with a 75 mmφ co-directional twin screw extruder. .
Adjust the amount of molten resin discharged from the extruder and the casting speed, and adjust the amount of molten resin discharged so that the thickness ratio of the surface layer, intermediate layer and back layer is 1: 5: 1. Quenched with a roll, an unstretched coextruded film of 300 μm or 40 μm was obtained.

(Samples 7, 8, 9, 11, 18)
As resin components, polylactic acid (trade name: NatureWorks 4032D, manufactured by Cargill Dow, USA) and polyolefin / polyoxyethylene block polymer (trade name: Pelestat 300, manufactured by Sanyo Chemical Co., Ltd.) as shown in Table 2 Multi-manifold type die at 210 ° C while mixing with a ratio of 95: 5, 90:10, 80:20, 70:30, 60:40 and degassing with 58mmφ co-directional twin screw extruder More extruded as front and back layers.
Further, the polylactic acid polymer having a structural unit of L-lactic acid: D-lactic acid = 98.5: 1.5 was extruded as an intermediate layer from the die at 210 ° C. with a 75 mmφ co-directional twin screw extruder. .
Next, the amount of molten resin discharged from the extruder and the casting speed were adjusted, and the amount of molten resin discharged was adjusted so that the thickness ratio of the surface layer, intermediate layer, and back layer was 1: 8: 1. The film was rapidly cooled with a casting roll at 0 ° C. to obtain an unstretched film.
This unstretched film was stretched 2.6 times while being heated to 74 ° C. with a roll and an infrared heater in the longitudinal direction using a biaxial stretching device, and then set to a preheating zone temperature of 72 ° C. with a tenter in the width direction. The zone was stretched 3.3 times at a temperature of 77 ° C. The temperature of the heat treatment zone in the tenter was set to 135 ° C. to produce a heat-treated biaxially stretched film.
The amount of molten resin discharged from the extruder and the line speed were adjusted so that the film thickness was approximately 40 μm to 50 μm on average.
The evaluation results of the film are shown in Table 2. In Comparative Example 6, the film surface was uneven and the appearance was remarkably inferior.

(Sample 10)
As a resin component, 80% by mass of polylactic acid (trade name: NatureWorks 4032D, manufactured by Cargill Dow, USA) and 20% by mass of polyolefin / polyoxyethylene block polymer (trade name: Pelestat 300, manufactured by Sanyo Chemical Co., Ltd.) are mixed. In addition, a total of 100 parts by mass of polylactic acid is mixed with 0.05 parts by mass of dried granular silica having an average particle diameter of 1.4 μm (trade name: Silicia 100, manufactured by Fuji Silysia Chemical Co., Ltd.). The sheet was extruded into a sheet form from the die at 210 ° C. while degassing with a directional twin screw extruder. A biaxially stretched film was produced from this extruded sheet in the same manner as Sample 7.
The amount of molten resin discharged from the extruder and the line speed were adjusted so that the film thickness was approximately 50 μm on average.
Table 3 shows the evaluation results of the film.

(Samples 12, 13)
As a resin component, polylactic acid (trade name: NatureWorks 4032D, manufactured by Cargill Dow, USA) and polyolefin / polyoxyethylene block polymer (trade name: Pelestat 300, manufactured by Sanyo Chemical Co., Ltd.) in a mass ratio of 70:30. Otherwise, the mixture was mixed so as to be 100: 0, and otherwise, in the same manner as Sample 3, an unstretched film having a thickness of 300 μm or 40 μm was obtained as shown in Table 3.
Table 3 shows the evaluation results of the film.

(Samples 14 and 15)
As a resin component, polylactic acid (trade name: NatureWorks 4032D, manufactured by Cargill Dow, USA) and polyolefin / polyoxyethylene block polymer (trade name: Pelestat 300, manufactured by Sanyo Chemical Co., Ltd.) in a mass ratio of 100: 0. Or it mixed so that it might be set to 97: 3, and others extruded similarly to the sample 1, and biaxially stretched and obtained the film of thickness 40 micrometers as Table 3.
Table 3 shows the evaluation results of the film.

(Samples 16 and 17)
As a resin component, polylactic acid (trade name: NatureWorks 4032D, manufactured by Cargill Dow, USA) and polyolefin / polyoxyethylene block polymer (trade name: Pelestat 300, manufactured by Sanyo Chemical Co., Ltd.) are used in a mass ratio of 60:40. Or it mixed so that it might be set to 50:50, and others were extruded like the sample 1, and it was going to biaxially stretch.
However, in the case of Sample 16, after the longitudinal stretching, a longitudinally stretched film was guided to the tenter and attempted to be stretched in the width direction, but breakage occurred midway. Although the temperature settings of the preheating zone and the stretching zone were each changed to 65 to 90 ° C., the fracture was not eliminated.
In the case of Sample 17, the extruded molten resin was rapidly cooled with a cast roll and taken up. However, the surface of the film was uneven, and the width of the sheet was severe, so-called draw resonance phenomenon occurred, and the appearance However, it was not possible to obtain an unstretched film having good thickness accuracy.

(Sample 19)
As the resin component, polylactic acid (trade name: NatureWorks 4032D, manufactured by Cargill Dow, USA) having a structural unit of L-lactic acid: D-lactic acid = 98.5: 1.5 and L-lactic acid: D-lactic acid = 94 .5: A polylactic acid having a structural unit of 5.5 (trade name: NatureWorks 4060D, manufactured by Cargill Dow, USA) and a polyolefin / polyoxyethylene block polymer (trade name: Pelestat 300, manufactured by Sanyo Chemical Co., Ltd.) , 20:50:30 in a mass ratio, and further 10 parts by mass of anatase-type titanium dioxide (trade name: TA-300, manufactured by Fuji Titanium Industry Co., Ltd.) with respect to 100 parts by mass of this resin component. The product was extruded as a front and back layer from a multi-manifold die at 210 ° C. while being deaerated with a 58 mmφ co-directional twin-screw extruder.
Further, a composition obtained by mixing 10 parts by mass of the same kind of titanium dioxide with 100 parts by mass of the polylactic acid polymer having a structural unit of L-lactic acid: D-lactic acid = 98.5: 1.5 is 75 mmφ. Was extruded as an intermediate layer at 210 ° C. from the above die.
Adjusting the amount of molten resin discharged from the extruder and the casting speed, adjusting the amount of molten resin discharged so that the thickness ratio of the surface layer, intermediate layer and back layer is 1: 10: 1, and casting at about 35 ° C. The film was quenched with a roll to obtain an unstretched film.

This unstretched film was stretched 2.5 times while being heated to 77 ° C with a roll and an infrared heater in the longitudinal direction using a biaxial stretching device, and then set to a preheating zone temperature of 70 ° C with a tenter in the width direction. The zone was stretched 3.0 times at a temperature of 74 ° C. The temperature of the heat treatment zone in the tenter was 142 ° C., and a heat-treated biaxially stretched film was produced.
The amount of molten resin discharged from the extruder and the line speed were adjusted so that the film thickness was approximately 250 μm on average.

  Next, the obtained film was cut into A2 size to form a sheet, and then printing was performed using ultraviolet curable ink FDO Indigo G (manufactured by Toyo Ink Manufacturing Co., Ltd.). The printing machine used SpeedmasterCD74 (made by HEIDELBERG). For each ink adhesion, serotape (Elpac LP-18 manufactured by Nichiban Co., Ltd.) was applied to the printed surface, and rubbed with a finger five times from above the serotape (registered trademark). Immediately thereafter, the serotape was peeled off at once, and the amount of the ink peeled was visually observed. The ink did not peel at all. The printed sheet was punched into a width of 86 mm and a length of 54 mm to obtain a card. When the card | curd which consists of this polylactic acid composition evaluated JIS, all were in the specification and it turned out that it is useful as a card | curd.

(Samples 20, 21, 22, and 23)
Cut the film obtained in Samples 3, 4, 10 and 11 to A3 size, and dilute the stock solution of the trade name REGITEXA5005 (manufactured by Regex Corp.) about 2 times with water on one side. This was applied with Mayer bar # 4. Next, the film was sandwiched between two metal frames of approximately A4 size and firmly fixed with metal clips. The film fixed with this frame was placed in a hot air circulation oven at about 70 ° C. and dried for 2 minutes.
The obtained film could be used as a protective film having adhesiveness.

(Samples 24, 25 and 26)
The film obtained in Samples 3, 5 and 12 above was clamped to a thermoforming machine (PLAVAC-FE36PH type manufactured by Sanwa Kogyo Co., Ltd.), preheated with an infrared heater so that the sheet temperature became 70 ° C., and then plugged Pre-molding was performed by pushing into the mold. The temperature at the time of preheating is obtained by sticking a thermocouple to the film in advance and examining the relationship between the capacity of the heater and the heating time.
Next, the mold shown in FIG. 1 was used, and the mold was evacuated to form a cup.

  With the above operation, a useful molded product could be obtained by thermoforming. Usually, in the vicinity where the film is clamped, improvement in impact resistance due to the effect of stretching by thermoforming cannot be expected, but in this case, a molded article having high impact resistance could be obtained.

Claims (9)

  A polylactic acid polymer (A) and a polyether ester amide polymer (B) are contained, and the ratio of the component (A) to the component (B) is 95: 5 to 65 by mass ratio. A polylactic acid composition characterized by being: 35.   A polylactic acid film having a single layer structure, comprising a resin layer containing the polylactic acid composition according to claim 1.   A polylactic acid film comprising a laminate structure of at least two layers, wherein the outermost layer on one side or both sides is a resin layer containing the polylactic acid composition according to claim 1.   A polylactic acid film comprising a laminate structure of at least three layers, wherein at least one of the intermediate layers is a resin layer containing the polylactic acid composition according to claim 1.   The polylactic acid film according to claim 2, which is stretched in at least one direction.   The polylactic acid film according to claim 2, 3 or 5, wherein the wetting index is 400 to 540 µN / cm.   The polylactic acid-based film according to claim 2, 3 or 5, wherein the logarithm LogR of the surface resistance R (Ω) is 13 or less. The polylactic acid film according to any one of claims 2 to 7, wherein the moisture permeability is 220 to 900 g / m ² · day. The measured value (hydroshot value) of a dirt type impact test is 200 to 500 N · mm, and the polylactic acid-based unstretched film according to any one of claims 2 to 4.