JP2010090370A - Laterally highly stretched aliphatic polyester-based film and laminated film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aliphatic polyester-based film which is excellent in a slit forming property, appearance of an end of a roll stored at room temperature, and a water vapor barrier property. <P>SOLUTION: The aliphatic polyester-based film has Δn of -30×10<SP>-3</SP>to -5×10<SP>-3</SP>, and a shrinkage rate in the film width direction after heating for 30 min at 120°C of -30 to 30%, and includes 50 to 100 mass% of the total amount of the aliphatic polyester and a stretching aid with respect to 100 mass% of total components of the film, and includes 60-99.9 mass% aliphatic polyester and 0.1-40 mass% stretching aid with respect to 100 mass% of the total amount of the aliphatic polyester and the stretching aid, wherein Δn is: (refractive index in the longitudinal direction of the film)-(refractive index in the lateral direction of the film). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a film made of an aliphatic polyester-based resin, and more particularly to an aliphatic polyester-based film and a laminated film excellent in slit property, roll end appearance at room temperature storage, and water vapor barrier property.

  Conventionally, various plastic films such as polyolefin, aromatic polyester, polyamide, and the like represented by polyethylene, polypropylene, polyethylene terephthalate, nylon 6 and the like are used for various packaging films including food. When these films for packaging materials are discarded in the natural environment after use, they remain without being decomposed due to their stability, so that the scenery is damaged and the living environment such as fish and wild birds is contaminated. Has become a serious problem. Under these circumstances, along with the recent increase in social awareness of environmental protection, when plastic products in general are disposed of in the natural environment, they will decompose and disappear over time and will not adversely affect the natural environment. There is a growing demand for plastic products.

  Along with this movement, various biodegradable polymer materials whose polymers themselves are biodegradable have been studied. Above all, polylactic acid is easily decomposed by microorganisms when discarded in a natural environment. Various developments have also been made for film applications.

  Among various biodegradable plastics, polylactic acid film has excellent mechanical properties equivalent to transparency, biodegradability, and general-purpose film. Various improvements have been made. There are various improvement means, and one of them is a method for improving the characteristics of an aliphatic polyester film such as a polylactic acid film by controlling the birefringence Δn. Patent Document 2 proposes an improvement in the flexibility of a polylactic acid film, Patent Document 2 proposes an improvement in thermal decomposability, and Patent Document 3 proposes an improvement in flatness, printability, and film meandering prevention. In Patent Document 3 and the like, an attempt is made to improve quality / physical properties such as film thickness unevenness, mechanical properties, and secondary workability by mainly increasing the stretching ratio in the transverse direction during the film production.

JP-A-2004-189940 (Claims 1 to 6, Examples) Japanese Patent Laid-Open No. 07-205278 (Claims 1 and 2, Examples) JP-A-2001-288281 (Claims 1-4, Examples)

  However, in Patent Document 1, since the thermal shrinkage rate is not sufficiently controlled, the thermal dimensional stability in processing such as molding and printing is insufficient, and the film-forming property becomes unstable even if high-strength stretching is attempted during the production. It was inferior in productivity and inferior in industrial practicality. Further, in Patent Document 2, the regulation of Δn is only related to after longitudinal stretching, and no teaching principle is disclosed regarding control of Δn after biaxial stretching. The property became unstable, the productivity was inferior, and the industrial practicality was inferior. Further, in Patent Document 3, the prescribed ranges of the birefringence Δn and the heat shrinkage rate are different from those of the present application, and are insufficient to bring out the effects of the present invention. Since the property becomes unstable, the productivity is inferior and the industrial practicality is inferior.

  Therefore, an object of the present invention is to provide an aliphatic polyester film and a laminated film excellent in slit property, end appearance at the time of storage at normal temperature, and water vapor barrier property.

  Packaging materials used for packaging foods, pharmaceuticals, precision electronic components, etc. are used to maintain the taste and freshness by suppressing the alteration of contents, especially the oxidation and alteration of proteins and oils and fats in the food field. In the field, it is necessary to prevent the effects of water vapor that permeates the packaging material in order to prevent the corrosion and insulation failure of metal parts in the field of precision electronic components in order to suppress the deterioration of active ingredients and maintain the efficacy. Therefore, it is required to have a barrier property to block these water vapors.

  In addition, slitting properties and good roll appearance at the time of long-term storage at normal temperature are listed as important properties during film production and storage. If the slit property is insufficient, the shape of the slit end face is not uniform at the time of film production, which may cause problems such as wrinkles and poor appearance or frequent replacement of the slit blade. In addition, chips generated by the slit may cause product defects by adhering to the film surface. On the other hand, when the film is stored in a rolled state at room temperature for a long time, a phenomenon that the appearance of the end part is deformed and deteriorated in the shape of a petal may be a problem.

  An object of this invention is to provide the manufacturing method of the aliphatic polyester-type film, laminated | multilayer film, and aliphatic polyester-type film which solved these problems by control of (DELTA) n, a heat shrinkage rate, etc. More preferably, the present invention aims to provide a film having improved productivity, quality, and physical properties by stably stretching at high magnification during the production process.

In order to achieve the above object, the aliphatic polyester film of the present invention has the following constitution. That is:
1) Δn is −30 × 10 ⁻³ to −5 × 10 ⁻³ ,
The shrinkage rate in the film width direction after heating at 120 ° C. for 30 minutes is −30% to 30%,
The total amount of aliphatic polyester and stretching aid is 50% by mass or more and 100% by mass or less with respect to 100% by mass of all components of the film,
A fat comprising 60% to 99.9% by weight of an aliphatic polyester and 0.1 to 40% by weight of a stretching aid with respect to 100% by weight of the total amount of the aliphatic polyester and the stretching aid. Group polyester film.
However,
Δn: (refractive index in the film longitudinal direction) − (refractive index in the film width direction)
2) The aliphatic polyester film according to 1) above, wherein the aliphatic polyester is polylactic acid.
3) The stretching aid is at least one selected from a polylactic acid-polyether block copolymer, a polylactic acid-polyester block copolymer, and an olefin acrylate copolymer polymer. ) Or 2) the aliphatic polyester film.
4) The F-2 value in the film longitudinal direction is 30 to 100 MPa, the F-2 value in the film width direction is 80 to 150 MPa,
The aliphatic polyester film according to any one of 1) to 3) above, wherein the F-2 value in the film longitudinal direction is smaller than the F-2 value in the film width direction.
5) A laminated film having a B layer on at least one side of the A layer,
The A layer is an aliphatic polyester film, and contains 50% by mass to 100% by mass of the aliphatic polyester and the stretching aid with respect to 100% by mass of all components of the A layer. 60 mass% to 99.9 mass% of aliphatic polyester and 0.1 to 40 mass% of stretching aid are contained with respect to 100 mass% of the total amount of polyester and stretching aid,
The B layer is an aliphatic polyester film, and the heat of fusion (ΔH) of the B layer is 0 to 40 J / g.
Laminated film, characterized in that Δn is ^{-30 × 10 -3 ~-5 ×} 10 -3, shrinkage of the film width direction after 30 minutes heating at 120 ° C. is 30% or less than -30%, Laminated film.
However,
Δn: (refractive index in the film longitudinal direction) − (refractive index in the film width direction)
6) The laminated film as described in 5) above, wherein the aliphatic polyester of the A layer is polylactic acid.
7) The B layer contains polylactic acid and a stretching aid,
In 100% by mass of all components of the B layer, 70% by mass or more is polylactic acid,
The laminated film as described in 5) or 6) above, wherein 0.5 to 20% by mass of a stretching aid is contained with respect to 100% by mass of the total amount of polylactic acid and stretching aid in the B layer.
8) Longitudinal stretching step in which Δn is 5 × 10 ⁻³ to 30 × 10 ⁻³ ,
And having a width direction stretching step in which the stretching ratio is 4 to 15 times in this order,
Characterized in that Δn is ^{-30 × 10 -3 ~-5 ×} 10 -3, shrinkage of the film width direction of 30 minutes after heating at 120 ° C. is 30% or less than -30%, the aliphatic polyester A method for producing a film.

  ADVANTAGE OF THE INVENTION According to this invention, the aliphatic polyester-type film excellent in slit property, the roll external appearance at normal temperature storage, and water vapor | steam barrier property, its manufacturing method, Furthermore, a laminated film can be obtained. The film obtained in the present invention can be preferably used for various packaging materials used for foods and various industrial materials.

Aliphatic polyester film of the present invention, [Delta] n is ^{-30 × 10 -3 ~-5 ×} 10 -3, 120 film width direction shrinkage of 30 minutes after heating at ℃ -30% to 30% or less, the film The total amount of the aliphatic polyester and the stretching aid is 50% by weight to 100% by weight with respect to 100% by weight of all the components, and the aliphatic polyester and the stretching aid are 100% by weight of the aliphatic polyester. It is an aliphatic polyester film characterized by containing 60% by mass to 99.9% by mass and 0.1 to 40% by mass of a stretching aid. Here, Δn = (refractive index in the film longitudinal direction) − (refractive index in the film width direction).

Furthermore, the laminated film of the present invention is a laminated film having a B layer on at least one side of the A layer, and the A layer is an aliphatic polyester film, and is 100% by mass of the total components of the A layer. The total amount of the aliphatic polyester and the stretching aid is 50% by mass to 100% by mass, and the aliphatic polyester is 60% by mass to 99.9% with respect to 100% by mass of the total amount of the aliphatic polyester and the stretching aid in the A layer. The layer B is an aliphatic polyester film, the heat of fusion (ΔH) of the layer B is 0 to 40 J / g, and is a laminated film. is, [Delta] n is ^{-30 × 10 -3 ~-5 ×} 10 -3, shrinkage of the film width direction after 30 minutes heating at 120 ° C. is a laminated film is not more than 30% or more 30%. However, Δn = (refractive index in the film longitudinal direction) − (refractive index in the film width direction).

  The ratio of the content of the aliphatic polyester and the stretching aid in the layer A of the aliphatic polyester film of the present invention and the laminated film of the present invention is more preferably 100% by mass of the total amount of the aliphatic polyester and the stretching aid. The aliphatic polyester is 70% by mass to 99.8% by mass, the stretching aid is 0.2 to 30% by mass, particularly preferably 100% by mass of the total amount of the aliphatic polyester and the stretching aid. The group polyester is 80 mass% to 99.5 mass%, and the stretching aid is 0.5 to 20 mass%.

Further, the total amount of the aliphatic polyester and stretching aid in 100% by mass of all components of the aliphatic polyester film of the present invention, and the aliphatic polyester and stretching aid in 100% by mass of all components of layer A of the laminated film of the present invention. It is important that the total amount of the polyester is 50% by mass or more and 100% by mass or less, but the total amount of the aliphatic polyester and the stretching aid in 100% by mass of the total components of the aliphatic polyester film, and the layer A of the laminated film. The total amount of aliphatic polyester and stretching aid in 100% by mass of all components is more preferably 70% by mass to 100% by mass, and still more preferably 80% by mass to 100% by mass.
(Aliphatic polyester)
Examples of the aliphatic polyester used in the aliphatic polyester film and laminated film of the present invention include polycondensates from aliphatic dicarboxylic acids and aliphatic diols, polycondensates of aliphatic hydroxycarboxylic acids, etc. There are no particular restrictions on the structure of the body or the polymerization method.

  Examples of such aliphatic polyesters include polybutylene sebacate, polybutylene succinate, polybutylene succinate / adipate, polypropylene sebacate, polypropylene succinate, polypropylene succinate / adipate, polylactic acid, polyglycolic acid Etc. can be used. Among these, it is preferable that polylactic acid is contained as the aliphatic polyester from the viewpoints of environment such as a plant-derived raw material, transparency and heat resistance. Therefore, the aliphatic polyester film of the present invention is preferably a polylactic acid film.

  The aliphatic polyester film of the present invention contains 50% by mass or more and 100% by mass or less of the aliphatic polyester and the stretching aid with respect to 100% by mass of all components of the film. 60% to 99.9% by weight of aliphatic polyester is contained with respect to 100% by weight of the total amount, more preferably aliphatic polyester with respect to 100% by weight of the total amount of aliphatic polyester and stretching aid. Is 70 mass% to 99.8 mass%, and particularly preferably is an embodiment containing 80 mass% to 99.5 mass% of aliphatic polyester with respect to 100 mass% of the total amount of aliphatic polyester and stretching aid. Similarly, the laminated film of the present invention contains 50% by mass or more and 100% by mass or less of the aliphatic polyester and the stretching aid with respect to 100% by mass of all components of the layer A, and the total amount of the aliphatic polyester and the stretching aid. 60 to 99.9% by weight of aliphatic polyester is contained with respect to 100% by weight, more preferably aliphatic polyester and 100% by weight of aliphatic polyester and stretching aid. 70 mass% to 99.8 mass%, and particularly preferred is an embodiment containing 80 mass% to 99.5 mass% of aliphatic polyester with respect to 100 mass% of the total amount of aliphatic polyester and stretching aid.

In addition, after that, in the layer A of the aliphatic polyester film and the laminated film of the present invention, 60 mass% to 99.9 mass% is contained with respect to 100 mass% of the total amount of the aliphatic polyester and the stretching aid. The aliphatic polyester is referred to as a main component aliphatic polyester.
(Polylactic acid)
In the aliphatic polyester film and laminated film of the present invention, the polylactic acid used as the main component aliphatic polyester is a polymer mainly composed of L-lactic acid and / or D-lactic acid unit. The poly-L-lactic acid referred to in the present invention is preferably such that the content of L-lactic acid units in the total lactic acid component of 100 mol% of the polylactic acid polymer is more than 50 mol% and not more than 100 mol%. The content ratio of the L-lactic acid unit in the total lactic acid component of the lactic acid polymer is more preferably from 80 mol% to 100 mol%, more preferably from 95 mol% to 100 mol%, and from 98 mol% to 100 mol%. Even more preferably. On the other hand, the poly-D-lactic acid referred to in the present invention preferably has a D-lactic acid unit content of more than 50 mol% and not more than 100 mol% in 100 mol% of the total lactic acid component of the polylactic acid polymer. The content ratio of the D-lactic acid unit in 100 mol% of the total lactic acid component of the polylactic acid polymer is more preferably 80 mol% or more and 100 mol% or less, more preferably 95 mol% or more and 100 mol% or less, and 98 mol% or more. Even more preferably, it is 100 mol% or less.

In poly L-lactic acid, the crystallinity of the resin itself varies depending on the content ratio of the D-lactic acid unit. That is, if the content ratio of the D-lactic acid unit in the poly-L-lactic acid increases, the crystallinity of the poly-L-lactic acid becomes lower and becomes closer to an amorphous state, and conversely, the content ratio of the D-lactic acid unit in the poly-L-lactic acid. As the amount decreases, the crystallinity of poly-L-lactic acid increases. Similarly, in poly D-lactic acid, the crystallinity of the resin itself changes depending on the content ratio of the L-lactic acid unit. That is, if the content ratio of the L-lactic acid unit in the poly-D-lactic acid increases, the crystallinity of the poly-D-lactic acid becomes low and approaches an amorphous state. Conversely, the content ratio of the L-lactic acid unit in the poly-D-lactic acid. As the amount decreases, the crystallinity of poly-D-lactic acid increases. In addition, when polylactic acid with low crystallinity is blended with polylactic acid with high crystallinity, it is preferable from the viewpoint of stretchability.
(Weight average molecular weight of aliphatic polyester)
The weight average molecular weight of the main component aliphatic polyester used in the aliphatic polyester film and laminated film of the present invention is 50,000 to 500,000 in order to satisfy appropriate film forming properties, stretchability and practical mechanical properties. It is preferable that it is 100,000-250,000. For the same reason, the weight average molecular weight of the polylactic acid used in the aliphatic polyester as the main component of the present invention is preferably 50,000 to 500,000, more preferably 100,000 to 250,000. In addition, a weight average molecular weight here means the molecular weight which measured with the chloroform solvent by the gel permeation chromatography (GPC), and was calculated by the polymethylmethacrylate conversion method.
(Monomer unit contained in aliphatic polyester)
The aliphatic polyester (main component) in the aliphatic polyester film of the present invention and in the layer A of the laminated film may be a copolymer containing the following monomer units in addition to the aliphatic polyester described above. . Other monomers include ethylene glycol, propylene glycol, butanediol, heptanediol, hexanediol, octanediol, nonanediol, decanediol, 1,4-cyclohexanedimethanol, neopentyl glycol, glycerin, pentane. Glycol compounds such as erythritol, bisphenol A, polyethylene glycol, polypropylene glycol and polytetramethylene glycol, oxalic acid, adipic acid, sebacic acid, azelaic acid, dodecanedioic acid, malonic acid, glutaric acid, cyclohexanedicarboxylic acid, terephthalic acid , Isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, bis (p-carboxyphenyl) methane, anthracene dicarboxylic acid, 4,4′-diphenyl ether dicarboxylic acid, -Dicarboxylic acids such as sodium sulfoisophthalic acid, 5-tetrabutylphosphonium isophthalic acid, glycolic acid, hydroxypropionic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxycaproic acid, hydroxybenzoic acid and other hydroxycarboxylic acids, caprolactone, valerolactone, Examples include lactones such as propiolactone, undecalactone, and 1,5-oxepan-2-one. When the main component aliphatic polyester is a polylactic acid resin, the copolymerization amount of the other monomer units is 0 to 30 mol% with respect to 100 mol% of the entire monomer units of the polylactic acid resin. It is more preferable, and it is more preferable that it is 0-10 mol%.
(Stretching aid)
In the aliphatic polyester film and the laminated film A of the present invention, it is important to contain a stretching aid mainly for the purpose of enhancing the stretchability of the film. The stretching aid in the present invention means a compound that generates pseudo-crosslinking points during film stretching and prevents film breakage.

  In the aliphatic polyester film of the present invention, the content of the stretching aid is such that the total amount of the aliphatic polyester and the stretching aid is 50% by mass or more and 100% by mass with respect to 100% by mass of all components of the aliphatic polyester film. It is important that the stretching aid is contained in an amount of 0.1 to 40% by weight with respect to 100% by weight of the total amount of aliphatic polyester and stretching aid, and the total amount of aliphatic polyester and stretching aid is 100. The content of the stretching aid with respect to mass% is more preferably 0.2 to 30 mass%, particularly preferably 0.5 to 20 mass%, and in the laminated film of the present invention, all components of layer A are 100 mass%. %, The total amount of the aliphatic polyester and the stretching aid is 50% by mass or more and 100% by mass or less, and the stretching aid is 0.00% with respect to the total amount of the aliphatic polyester and the stretching aid of 100% by mass. It is important to contain -40% by mass, and the content of the stretching aid relative to the total amount of aliphatic polyester and stretching aid of 100% by mass is more preferably 0.2-30% by mass, particularly preferably 0.5. ˜20 mass%. When the content of the stretching aid is 0.1% by mass or more with respect to 100% by mass of the total amount of the aliphatic polyester and the stretching aid, the effect of the stretching aid to be added is preferable. Moreover, when it is 40 mass% or less, it is preferable from the point which can maintain transparency and heat resistance of an aliphatic polyester film and a laminated film.

  Examples of the stretching aid added to the layer A of the aliphatic polyester film and laminated film of the present invention include, for example, polyacetal, polyolefin, olefin acrylate copolymer polymer, polyamide, poly (meth) acrylate, polyphenylene sulfide, and polyether. Thermosetting resins such as ether ketone, polyester resin, polysulfone, polyphenylene oxide, polyimide, polyetherimide, thermosetting resins such as phenol resin, melamine resin, polyester resin, silicone resin, epoxy resin, ethylene / glycidyl methacrylate copolymer Examples thereof include soft thermoplastic resins such as coalescence, polyester elastomer, polyamide elastomer, ethylene / propylene / butene terpolymer, and ethylene / butene-1 copolymer.However, the aliphatic polyester film of the present invention and the main component aliphatic polyester in layer A of the laminated film (containing 60 mass% or more and 99.9 wt% or less with respect to 100 mass% of the total amount of aliphatic polyester and stretching aid) The aliphatic polyester) and the stretching aid are different. Moreover, you may use extending | stretching adjuvant in combination of 2 or more types.

  As the stretching aid, among the above resins, a polyester resin and an olefin acrylate copolymer polymer different from the main component aliphatic polyester are preferable, and thereby the stretchability of the aliphatic polyester film and laminated film of the present invention is improved. It is preferable from the point which becomes favorable.

Examples of methods for including Δn to ^{-30 × 10 -3 ~-5 ×} 10 -3 is the range of the present invention, there is a method of increasing the stretching ratio in the width direction compared with the longitudinal stretch ratio. In ordinary aliphatic polyester films and laminated films, film stretching tends to occur and thickness unevenness increases when stretched in the width direction at a high magnification, but the main component aliphatic polyester is used as a stretching aid. By improving the stretchability by adding a polyester resin different from the above, it becomes possible to form a film with suppressed film breakage and thickness unevenness.

  In the case of the aliphatic polyester film of the present invention and the A layer of the laminated film, when the aliphatic polyester as the main component is polylactic acid, the stretching aid is a polylactic acid-polyether block copolymer, polylactic acid- It is preferably at least one selected from a polyester block copolymer and an olefin acrylate copolymer polymer.

  When using a polylactic acid-polyether block copolymer and / or a polylactic acid-polyester block copolymer as a stretching aid, the polylactic acid portion of these compounds is compatible with the polylactic acid of the film main component, When an olefin acrylate copolymer polymer is used as a stretching aid, the acrylic part in the compound has good compatibility with polylactic acid. When these stretching aids are used, the compatible portions of the stretching aid and the polylactic acid that is the main component of the film, the aliphatic polyester, act as pseudo-crosslinking points, resulting in good stretchability. To preferred.

  Moreover, when using an olefin acrylate copolymer polymer as extending | stretching adjuvant, it is especially preferable that an olefin part is ethylene. As an example of the olefin acrylate copolymer polymer, Biomax Strong 120 manufactured by DuPont is preferably used.

  A method for producing a polylactic acid-polyether block copolymer and / or a polylactic acid-polyester block copolymer is not particularly limited, but a method obtained by polymerizing a polyether and / or a polyester other than polylactic acid with lactide. Etc. As the polyether used in the production of the polylactic acid-polyether block copolymer, polyethylene glycol, polyethylene glycol / polypropylene glycol copolymer, polypropylene glycol and the like are preferably used. Moreover, as an example of the polylactic acid-polyester copolymer, Puramate PD-150 manufactured by Dainippon Ink & Chemicals, Inc. is preferably used.

  Polyether units in the polylactic acid-polyether block copolymer, polylactic acid units, polyester units other than polylactic acid in the polylactic acid-polyester block copolymer, and weight average molecular weights of the polylactic acid units are 1,000 to 50,000 is preferable, and 2,000 to 30,000 is more preferable. The weight average molecular weight of the polylactic acid-polyether block copolymer and the polylactic acid-polyester block copolymer is 5,000 to 110,000.

In the aliphatic polyester film of the present invention, the main component aliphatic polyester is polylactic acid, and a polylactic acid-polyether block copolymer, a polylactic acid-polyester block copolymer, and an olefin acrylate copolymer are used as stretching aids. When using at least 1 sort (s) chosen from a polymer, it is especially preferable that content of extending | stretching adjuvant is 0.5-20 mass% with respect to 100 mass% of total amounts of polylactic acid and extending | stretching adjuvant. Similarly, in the layer A of the laminated film of the present invention, the main component aliphatic polyester is polylactic acid, and a polylactic acid-polyether block copolymer, polylactic acid-polyester block copolymer, olefin acrylate is used as a stretching aid. When using at least one selected from copolymer polymers, the content of the stretching aid is particularly preferably 0.5 to 20% by mass with respect to 100% by mass of the total amount of polylactic acid and the stretching aid. . When the content of the stretching aid is less than 0.5% by mass, the effect of improving the stretchability expected as the effect of adding the stretching aid may not be obtained. The improvement effect cannot be obtained, and transparency may be lowered or extrusion castability may be deteriorated. In particular, when the polylactic acid-polyether block copolymer or the polylactic acid-polyester block copolymer is used as a stretching aid, if the amount exceeds 20% by mass, the film becomes unnecessarily large when the film of the present invention is produced. In some cases, the film-forming property may be deteriorated due to softening. Therefore, the stretching aid is more preferably 1 to 15% by weight, and most preferably 3 to 10% by weight with respect to 100% by weight of the total amount of polylactic acid and the stretching aid.
(Additive)
In the aliphatic polyester film and laminated film of the present invention, additives, for example, flame retardants, heat stabilizers, light stabilizers, antioxidants, are necessary as long as the effects of the present invention are not impaired. Anti-coloring agents, UV absorbers, antistatic agents, plasticizers, crystal nucleating agents, tackifiers, organic lubricants such as fatty acid esters and waxes, antifoaming agents such as polysiloxanes, and coloring agents such as pigments and dyes An appropriate amount can be blended. The additive can be contained in an amount of 0% by mass to 50% by mass with respect to 100% by mass of all components of the aliphatic polyester film of the present invention, and 100% by mass of all components of layer A of the laminated film of the present invention. It can be contained in an amount of 0% by mass or more and 50% by mass or less, and further can be contained in an amount of 0% by mass or more and 50% by mass or less with respect to 100% by mass of all components of the B layer of the laminated film of the present invention.
(Added particles)
If necessary, particles can be added to the aliphatic polyester film and laminated film of the present invention as long as the effects of the present invention are not impaired. The particles can be contained in an amount of 0% by mass to 10% by mass with respect to 100% by mass of all components of the aliphatic polyester film. Similarly, 0% by mass with respect to 100% by mass of all components of the layer A of the present invention % To 10% by mass, and 0% by mass to 10% by mass with respect to 100% by mass of all components of the B layer. The type of particles is appropriately selected depending on the purpose and application, and is not particularly limited as long as the effects of the present invention are not impaired. Examples thereof include inorganic particles, organic particles, crosslinked polymer particles, and internal particles generated in the polymerization system. be able to. Each particle may be used alone or in combination.

  The inorganic particles are not particularly limited, but silicon oxide such as silica, various carbonates such as calcium carbonate, magnesium carbonate and barium carbonate, various sulfates such as calcium sulfate and barium sulfate, various composite oxides such as kaolin and talc. Fine particles comprising various phosphates such as lithium phosphate, calcium phosphate, and magnesium phosphate, various oxides such as aluminum oxide, titanium oxide, and zirconium oxide, and various salts such as lithium fluoride can be used.

  As the organic particles, fine particles made of calcium oxalate, terephthalate such as calcium, barium, zinc, manganese, magnesium, or the like are used. Examples of the crosslinked polymer particles include fine particles made of a vinyl monomer such as divinylbenzene, styrene, acrylic acid or methacrylic acid, or a copolymer. In addition, organic fine particles such as polytetrafluoroethylene, benzoguanamine resin, thermosetting epoxy resin, unsaturated polyester resin, thermosetting urea resin, and thermosetting phenol resin are also preferably used.

As the internal particles generated in the polymerization system, particles generated by a known method in which an alkali metal compound, an alkaline earth metal compound, or the like is added to the reaction system and a phosphorus compound is further added may be used.
(coating)
A functional layer may be provided on the surface of the aliphatic polyester film and laminated film of the present invention for the purpose of blocking prevention, antistatic property, imparting releasability, and improving scratch resistance. The functional layer can be formed by an in-line coating method performed in the film manufacturing process, an off-line coating method performed after the film is wound, or the like. Specific methods for forming such a functional layer include a wire bar coating method, a doctor blade method, a micro gravure coating method, a gravure roll coating method, a reverse roll coating method, an air knife coating method, a rod coating method, a die coating method, A kiss coating method, a reverse kiss coating method, an impregnation method, a curtain coating method, a spray coating method, an air doctor coating method, or a coating method other than these can be applied alone or in combination.

  Examples of in-line coating methods include a method of applying a coating solution to an unstretched film, a method of applying a coating solution to an unstretched sheet and biaxially stretching sequentially or simultaneously, and a method of applying a coating solution to a uniaxially stretched film. Further, there are a method of stretching in a direction perpendicular to the previous uniaxial stretching direction, a method of further stretching after coating the coating solution on a biaxially stretched film, and the like.

In addition, in order to improve the applicability | paintability to the film of a coating liquid and adhesiveness, a chemical process and an electrical discharge process can be given to the aliphatic polyester-type film and laminated | multilayer film of this invention before application | coating.
(Barrier layer)
In the aliphatic polyester film and laminated film of the present invention, a barrier layer may be formed on at least one surface for the purpose of improving water vapor barrier properties and gas barrier properties. The barrier layer can be provided by a technique such as coating, vapor deposition, or lamination. However, a vapor deposition layer made of a metal or a metal oxide is more preferable because it does not depend on humidity and can exhibit a barrier property with a thin film.

  The metal or metal oxide used for the vapor deposition layer is preferably made of any of aluminum, aluminum oxide, silicon oxide, cerium oxide, calcium oxide, diamond-like carbon film, or a mixture thereof. In particular, aluminum deposition is more preferable because it is economical and has excellent barrier performance. In addition, as a method for producing a vapor deposition thin film, a physical vapor deposition method such as a vacuum vapor deposition method, an EB vapor deposition method, a sputtering method, and an ion plating method, and various chemical vapor deposition methods such as plasma CVD can be used. From the viewpoint, the vacuum deposition method is particularly preferably used.

When providing the vapor deposition layer, it is preferable to pre-treat the surface to be vapor-deposited by a method such as corona discharge treatment in order to improve the adhesion of the vapor deposition film. Processing strength when subjected to corona treatment is preferably 5~50W · min / ^{m 2,} more preferably 10~45W · min / ^{m 2.} Furthermore, surface treatment such as gas treatment, plasma treatment, alkali treatment, electron beam radiation treatment, etc. may be performed as necessary.
The barrier layer may be formed on at least one side, but may be formed on both sides when high water vapor barrier property and high gas barrier property are required.

  Thus, when the vapor deposition layer is provided on at least one side of the aliphatic polyester film and laminated film of the present invention, the adhesion of the vapor deposition layer to the aliphatic polyester film and laminated film of the present invention is 50 g / 15 mm or more. Preferably there is. When the adhesion of the deposited layer is less than 50 g / 15 mm, during the deposition process, or when the deposited film (a deposited film means a film having a deposited layer) is further processed (for example, lamination, bag making, etc.). In addition, the gas barrier performance may be deteriorated due to peeling of the vapor deposition layer or cracks in the vapor deposition layer. The adhesion strength of the vapor deposition layer to the aliphatic polyester film and laminated film of the present invention is more preferably 70 g / 15 mm or more, further preferably 100 g / 15 mm or more, and most preferably 200 g / 15 mm or more. Also, the upper limit that can be achieved in practice is considered to be about 2000 g / 15 mm.

Moreover, when laminating a vapor deposition layer on the laminated film of the present invention as described below, the vapor deposition layer is preferably formed on the B layer.
(Thickness)
The thickness of the A layer of the aliphatic polyester film and laminated film of the present invention is preferably 5 to 500 μm. More preferably, it is 10-100 micrometers, More preferably, it is 12-30 micrometers. When the thickness of the A layer of the aliphatic polyester film and laminated film of the present invention is smaller than 5 μm, film breakage may easily occur during film formation. Moreover, when the thickness of the layer A of the aliphatic polyester film and laminated film of the present invention is larger than 500 μm, the stretchability may deteriorate.
(Laminated)
The structure of the aliphatic polyester film of the present invention may be a single layer, and the surface of the aliphatic polyester film of the present invention is easy to slip, adhesive, tacky, heat resistant, weather resistant, etc. A layered structure in which a layer for imparting a function is formed may be used. Examples of the laminated structure include two layers of A / B, three layers of B / A / B, B / A / C, and A / B / C. Furthermore, if necessary, it may have a laminated structure of more than three layers, and the lamination thickness ratio of each layer can be arbitrarily set. In the case of a laminated structure, each layer may contain a layer other than the aliphatic polyester as a main component of the film of the present invention, but at least one layer should satisfy the requirements for the aliphatic polyester film of the present invention. Is preferred. More preferably, for at least the thickest layer, it is important to meet the requirements of the aliphatic polyester film of the present invention. That is, at least for the thickest layer, the proportion of the total amount of the aliphatic polyester and the stretching aid out of 100% by mass of the total component of the film of the layer is 50% by mass or more and 100% by mass or less. It is preferable that 60% by mass to 99.9% by mass of the aliphatic polyester and 0.1 to 40% by mass of the stretching aid are contained with respect to 100% by mass of the total amount of the stretching aid. As a lamination method, for example, a known film production method such as a co-extrusion lamination method, a lamination method, a dry lamination method, or the like can be used. Among these methods, a co-extrusion lamination method that is melt-bonded at the time of film production is produced. It is preferable from the viewpoint of cost.

In particular, when the film of the present invention has a laminated structure, as described above, it is a laminated film having a B layer on at least one side of the A layer, and the A layer is an aliphatic polyester film, The total amount of aliphatic polyester and stretching aid is 50% by weight to 100% by weight with respect to 100% by weight of all components, and aliphatic with respect to 100% by weight of the total amount of aliphatic polyester and stretching aid in layer A. The polyester contains 60% by mass to 99.9% by mass and 0.1 to 40% by mass of a stretching aid, the B layer is an aliphatic polyester film, and the heat of fusion (ΔH) of the B layer is 0. The laminated film has a shrinkage rate in the film width direction after heating for 30 minutes at 120 ° C. of −30% to 30% and not more than 30%, Δn being −30 × 10 ⁻³ to −5 × 10 ⁻³ . A certain laminated film It is preferable. In addition, Δn = (refractive index in the film longitudinal direction) − (refractive index in the film width direction). More preferably, the aspect in which the aliphatic polyester of the A layer is polylactic acid, the B layer contains polylactic acid and a stretching aid, and 70% by mass or more of the total component of 100% by mass of the B layer is poly It is lactic acid, and is a laminated film in an aspect containing 0.5 to 20% by mass of a stretching aid with respect to 100% by mass of the total amount of polylactic acid and stretching aid in the B layer. Details of the laminated film of the present invention will be described below.

  In the case of forming a laminated structure in the present invention, an aliphatic polyester film (B layer) having a heat of fusion (ΔH) measured by a differential scanning calorimeter (DSC) of 0 to 40 J / g on at least one surface of the aforementioned A layer. ) Are preferably laminated films. By laminating such a specific B layer, when the laminated film of the present invention is processed to form a printed layer, a coat layer, a vapor deposition layer or the like on the B layer, the adhesion of these layers can be improved. There is a case.

  Moreover, in the laminated film of the present invention, when the aliphatic polyester as the main component of the aliphatic polyester film that is the A layer is polylactic acid, the aliphatic polyester of the B layer in the laminated film has transparency of the entire film, From the viewpoint of heat resistance and plant degree, it is preferable that 70% by mass or more and 100% by mass or less of polylactic acid is 100% by mass or less with respect to 100% by mass of all components of the B layer. More preferably, it is 80 mass% or more and 100 mass% or less, More preferably, it is 90 mass% or more and 100 mass% or less, and it is the most preferable that B layer consists of polylactic acid substantially.

  The content of the D-lactic acid unit in the total lactic acid component of the polylactic acid in the B layer is preferably 4 to 20 mol%. By setting the D-lactic acid unit content of the polylactic acid in the B layer in the range of 4 to 20 mol%, the laminated film of the present invention was processed to form a printed layer, a coat layer, a vapor deposition layer, etc. on the B layer. In some cases, the adhesion of these layers may be improved. The D-lactic acid unit content is more preferably 6 to 18 mol%, and even more preferably 8 to 15 mol%. In order to make the content of D-lactic acid units in the range of 4 to 20 mol%, a method for controlling the amount of D-lactic acid units in the polymerization step, the amount of L-lactic acid units, polylactic acid having different amounts of D-lactic acid units And the like, and the latter is preferable from the viewpoint of productivity. For example, a method of mixing 4032D (D-lactic acid amount: 1.2 mol%) with Nature Works 4060D (D-lactic acid amount: 12 mol%), which is a commercially available polylactic acid, is preferably performed from the viewpoint of productivity.

  Furthermore, in order to enhance the stable film-forming property at the time of transverse high-magnification stretching, and further to fully exhibit the effect of being excellent in slit property, roll appearance at room temperature storage, and water vapor barrier property, the B layer is A It is preferable that a stretching aid is included as well as the layer. When layer B contains a stretching aid like layer A, stretchability (co-stretchability) with layer A during film formation may be improved, and film forming properties may be improved. In addition, because the layer B contains a stretching aid, the rigidity of the surface of the layer B after film formation is lowered, or the laminated film of the present invention is processed to form a printed layer, a coat layer, and a vapor deposition layer on the layer B. In some cases, the adhesion with these layers can be further improved. The content of the stretching aid in the B layer is 0.5 to 20 mass with respect to 100 mass% of the total amount of the polylactic acid and the stretching aid in the B layer from the viewpoints of transparency, heat resistance, film forming property, and the like. %, More preferably 1 to 15% by mass, and most preferably 3 to 10% by mass. When layer B is polylactic acid, as in layer A, at least one selected from a polylactic acid-polyether block copolymer, a polylactic acid-polyester block copolymer, and an olefin acrylate copolymer polymer as a stretching aid Is preferably used as a stretching aid.

  It is preferable that the thickness of B layer in a laminated film is 0.1-10 micrometers. If the thickness of the B layer is less than 0.1 μm, uniform lamination may be difficult, and the effect of improving the adhesion as described above may be reduced. On the other hand, when the thickness exceeds 10 μm, the influence of the B layer on the properties of the laminated film is increased, which may cause a decrease in the rigidity of the film, an increase in heat shrinkage rate, a decrease in water vapor barrier properties, and the like. The layer B is laminated on at least one side of the layer A by coextrusion lamination method, inline or offline extrusion lamination, inline or offline coating, dry lamination, etc., but the lamination method is not limited to any of these. However, the best method can be selected at any time.

Further, regarding the relationship between the thicknesses of the A layer and the B layer in the laminated film, the thickness of the A layer is preferably thicker than the thickness of the B layer. Furthermore, when the B layer is laminated on both sides of the A layer, the thickness of the A layer is preferably larger than the sum of the thicknesses of the two B layers.
(Birefringence Δn)
In the aliphatic polyester film and laminated film of the present invention, the birefringence Δn represented by Δn = (refractive index in the film longitudinal direction) − (refractive index in the film width direction) is −30 × 10 ⁻³ to −5. It is important to be × 10 ⁻³ . More preferably ^{-26 × 10 -3 ~-6 ×} 10 -3, more preferably from ^{-22 × 10 -3 ~-7 ×} 10 -3. When Δn is larger than −5 × 10 ⁻³ , the water vapor barrier property and the slit property may be deteriorated. Moreover, when Δn is less than −30 × 10 ⁻³ , the flatness of the film may be easily deteriorated.

As a method for the Δn in the range of ^{-30 × 10 -3 ~-5 ×} 10 -3, but are not particularly limited, for example, a transverse stretching ratio of the film was greater than the longitudinal stretch ratio, the film Examples thereof include a method of making the refractive index in the width direction larger than the refractive index in the vertical direction. In addition, 2-5 times are preferable for the longitudinal draw ratio here, More preferably, it is 2.5-4 times. Further, the transverse draw ratio is preferably 2.5 to 15 times, more preferably 4 to 15 times, and still more preferably 5 to 10 times.
(Stretch ratio)
The aliphatic polyester film and laminated film of the present invention are preferably stretched 6 to 15 times in at least one direction in order to increase productivity during production of the film. Thus, by stretching at a high magnification, the slit property and water vapor barrier property of the resulting film can be improved. The aliphatic polyester film and laminated film of the present invention are more preferably produced by a sequential biaxial stretching method, and more preferably stretched 6 to 15 times in the transverse direction. The transverse draw ratio is preferably 6 to 12 times, more preferably 7 to 12 times, and most preferably 8 to 10 times. Such a high transverse stretching ratio is equivalent to that at the time of producing a biaxially oriented polypropylene film (OPP), for example. Therefore, even when the production of the aliphatic polyester film of the present invention is newly started by the transverse high-magnification stretching in which the transverse stretching is performed at 6 to 15 times as shown here, no completely new equipment is introduced. However, there is also a great advantage in terms of equipment that can be used for remodeling existing OPP equipment. In addition, as described above, in order to stably perform such high magnification stretching, it is important to add a stretching aid to the A layer and the B layer of the aliphatic polyester film and the laminated film of the present invention.
(Heat shrinkage)
In the aliphatic polyester film and laminated film of the present invention, it is important that the heat shrinkage ratio after heating for 30 minutes at 120 ° C. in the film width direction is −30% or more and 30% or less. From the viewpoint of improving the dimensional stability when the film is subjected to heat processing such as molding or printing, it is preferably −5% to 10%, more preferably −3% to 7%, and still more preferably − The range is 0.5% or more and 5% or less. In addition, the minus (-) of the heat shrinkage rate indicates the elongation of the film. If the heat shrinkage rate is greater than 30%, the film may shrink significantly during film heating processing such as printing or molding, and if it is less than -30%, the film may stretch during heat processing, resulting in wrinkles and process troubles and molded products. May deteriorate the appearance. In addition, it is preferable to control the heat shrinkage rate in the width direction in order to improve the appearance of the roll during storage at room temperature.

  Although there is no particular limitation on the method for setting the heat shrinkage ratio after heating for 30 minutes at 120 ° C. in the film width direction to be in the range of −30% to 30%, for example, 10% of the film in advance in the film production process. Heat treatment (heat setting) at a relatively high temperature below the melting point of the film of about 120 to 150 ° C. while relaxing in the following range, or 120 to 150 ° C. while relaxing the film once wound in a heating oven For example, a method of performing heat treatment at a moderate temperature can be used.

Depending on the application, the heat shrinkage ratio after heating for 30 minutes at 120 ° C. is preferably greater than 5% and 30% or less in the film width direction from the viewpoint of improving the workability of the film and the water vapor barrier property. More preferably, it is larger than 5% and 20% or less, and more preferably larger than 5% and 10% or less.
(F-2 value)
The aliphatic polyester film and laminated film of the present invention have a stress at 2% elongation at room temperature (23 ° C.) of 30 to 100 MPa in the film longitudinal direction and 80 to 150 MPa in the film width direction, and room temperature (23 ° C. ), The film longitudinal direction is preferably smaller than the film width direction (hereinafter, the stress at 2% elongation at room temperature (23 ° C.) is defined as F-2 value). More preferably, the F-2 value in the film longitudinal direction is 40 to 90 MPa, the F-2 value in the film width direction is 85 to 130 MPa, and the F-2 value in the longitudinal direction is smaller than the F-2 value in the width direction. More preferably, the F-2 value in the film longitudinal direction is 50 to 80 MPa, the F-2 value in the film width direction is 90 to 110 MPa, and the F-2 value in the longitudinal direction is more than the F-2 value in the width direction. It is a small aspect.

  When the F-2 value in the longitudinal direction is smaller than 30 MPa or the F-2 value in the width direction is smaller than 80 MPa, the heat resistance of the container obtained by molding the film is lowered, and deformed when used at a high temperature. Since it may become easy to do, it is not preferable. Moreover, when the F-2 value in the longitudinal direction is larger than 100 MPa or the F-2 value in the width direction is larger than 150 MPa, the film may be inferior in formability. Moreover, when the F-2 value in the longitudinal direction is equal to or greater than the F-2 value in the width direction, the water vapor barrier property and the slit property may be deteriorated.

The F-2 value is 30 to 100 MPa in the film longitudinal direction, 80 to 150 MPa in the film width direction, and the method for making the film longitudinal direction smaller than the film width direction is not particularly limited. For example, a method in which the transverse stretching ratio of the film is made larger than the longitudinal stretching ratio and the refractive index in the film width direction is made larger than the refractive index in the longitudinal direction. In addition, 2-5 times are preferable for the longitudinal draw ratio here, More preferably, it is 2.5-4 times. Further, the transverse draw ratio is preferably 2.5 to 15 times, more preferably 4 to 15 times, and still more preferably 5 to 10 times.
(Carboxyl terminal concentration)
The aliphatic polyester film and the laminated film of the present invention have a carboxyl group terminal concentration of the aliphatic polyester in the film from the viewpoint of suppressing the strength reduction due to the decomposition of the film and the product obtained by using the film and improving the heat resistance. Is preferably 30 equivalents / 10 ³ kg or less, more preferably 20 equivalents / 10 ³ kg or less, and even more preferably 10 equivalents / 10 ³ kg or less. When the carboxyl group terminal concentration in the polylactic acid-based resin exceeds 30 equivalents / 10 ³ kg, the strength is increased by hydrolysis when the film and container are used under high temperature and high humidity conditions or contact conditions with hot water. In some cases, the molded product such as a container becomes brittle and easily breaks.

Examples of the method for setting the carboxyl group terminal concentration of the film to 30 equivalents / 10 ³ kg or less include, for example, a method of controlling by a catalyst and a heat history at the time of synthesizing a polylactic acid-based resin, a reduction or retention of the extrusion temperature at the time of film formation Examples thereof include a method of reducing thermal history such as shortening the time, a method of blocking a carboxyl group end using a reactive compound, and the like.

In the method of blocking the carboxyl group terminal using a reactive compound, it is preferable that at least a part of the carboxyl group terminal in the film is blocked, and it is more preferable that the whole amount is blocked. Examples of reactive compounds include condensation reactive compounds such as aliphatic alcohols and amide compounds, and addition reactive compounds such as carbodiimide compounds, epoxy compounds, and oxazoline compounds, but extra by-products are generated during the reaction. Addition reaction type compounds are preferred because of their difficulty.
(Water vapor transmission rate)
From the viewpoint of using the aliphatic polyester film and laminated film of the present invention as a part of a packaging material or a package, the water vapor transmission rate before forming the metal vapor deposition layer is preferably 100 g / m ² / day or less, more Preferably it is 60 g / m < ² > / day or less, More preferably, it is 30 g / m < ² > / day or less. Moreover, it seems that the lower limit which can be achieved realistically is about 1 g / m ² / day.

The water vapor transmission rate after forming the metal vapor deposition layer with respect to the aliphatic polyester film or laminated film of the present invention is preferably 1.0 g / m ² / day or less, more preferably 0.8 g / m ² / day. Day or less, more preferably 0.6 g / m ² / day or less. Moreover, it seems that the lower limit which can be achieved practically is about 0.01 g / m ² / day.
(Production method)
Next, the method for producing the aliphatic polyester film and laminated film of the present invention will be specifically described by taking the case where the aliphatic polyester is polylactic acid as an example.

  The biaxially stretched polylactic acid film of the present invention is obtained by drying a resin mainly composed of polylactic acid and supplying it to an extruder to obtain a non-oriented unstretched film, which is stretched. This stretching can be performed by existing stretched film manufacturing methods such as inflation, simultaneous biaxial stretching, and sequential biaxial stretching, but it is easy to control the orientation state of the film that achieves both formability and heat resistance. In addition, the sequential biaxial stretching method is preferable because the film forming speed can be increased. Although the preferable film forming method in the case of performing tenter type | formula sequential biaxial stretching is shown below, it is not limited to this.

  A polylactic acid resin dried at 50 to 120 ° C. for 3 hours or more under a reduced pressure of 5 torr or less was discharged from a slit-shaped die having a lip interval of 1 to 3 mm by a T-die method, and the diameter was 0.5 mm on a metal cooling casting drum. A non-oriented cast film is obtained by applying a static electricity using the wire-shaped electrode and bringing it into close contact.

  The preferable range of the surface temperature of the metallic cooling roll is 0 to 30 ° C, the more preferable range is 3 to 25 ° C, and the further preferable range is 5 to 20 ° C. Good transparency can be expressed by setting the surface temperature of the metallic cooling roll within this range.

  The unstretched film thus obtained is heated to a temperature at which it is longitudinally stretched by being conveyed on a heating roll. An auxiliary heating means such as an infrared heater may be used in combination for raising the temperature. A preferable range of the stretching temperature is 55 to 85 ° C, more preferably 60 to 80 ° C, and further preferably 65 to 75 ° C. The unoriented film heated in this way is stretched in one or two or more stages in the longitudinal direction of the film using the peripheral speed difference between the heating rolls. The total draw ratio is preferably 2 to 5 times, more preferably 2.5 to 4 times.

  After the film uniaxially stretched in this way is once cooled, both ends of the film are held with clips and guided to a tenter, and stretched in the width direction. The stretching temperature is preferably 60 to 105 ° C, more preferably 65 to 100 ° C, and still more preferably 70 to 95 ° C. The draw ratio is preferably 2.5 to 15 times, more preferably 4 to 15 times, and still more preferably 5 to 10 times. Usually, the polylactic acid biaxially stretched film is often stretched at a lateral stretching ratio of 2.5 to 3.5 times, and if the lateral stretching ratio is further increased, there is a concern that the film-forming property is deteriorated. . In particular, when the draw ratio exceeds 6 times, the film-forming property often remarkably deteriorates. The aliphatic polyester film and laminated film of the present invention can improve the film-forming stability at the time of transverse high magnification stretching by using an appropriate amount of the stretching aid as exemplified above, and the aliphatic polyester film and laminated film. In some cases, uneven thickness can be improved. Moreover, it is preferable because the transverse high magnification stretching improves the slit property, the roll appearance during storage at room temperature, and the water vapor barrier property, and can make them compatible. Moreover, when the performance difference of the width direction of a film is seen, it can reduce by extending | stretching the width direction at the temperature 1-15 degreeC lower than the extending | stretching temperature of a longitudinal direction.

  Further, if necessary, re-longitudinal stretching and / or re-lateral stretching may be performed.

  Next, this stretched film is heat-set under tension or while relaxing in the width direction. A preferable heat treatment temperature is 90 to 160 ° C, more preferably 105 to 155 ° C, and further preferably 120 to 150 ° C. When it is desired to reduce the thermal shrinkage rate of the film, the heat treatment temperature is preferably increased. The heat treatment time is preferably in the range of 0.2 to 30 seconds, but is not particularly limited. The relaxation rate is preferably 3 to 15%, more preferably 5 to 10% from the viewpoint of reducing the heat shrinkage rate in the width direction. More preferably, the film is once cooled before the heat setting treatment. Further, the film is cooled and wound up to room temperature, if necessary, while relaxing in the longitudinal and width directions, if necessary, to obtain the desired biaxially stretched polylactic acid film.

  By employing the above production method, the biaxially stretched polylactic acid film of the present invention can be obtained.

Incidentally, [Delta] n is ^{-30 × 10 -3 ~-5 ×} 10 -3 of the present invention, the aliphatic polyester-based shrinkage in the film width direction of 30 minutes after heating at 120 ° C. is 30% or less than -30% Film A more preferable production method is a production method having a longitudinal direction stretching step in which Δn is 5 × 10 ⁻³ to 30 × 10 ⁻³ and a width direction stretching step in which the stretching ratio is 4 to 15 times in this order. is there.

The longitudinal stretching step in which Δn is 5 × 10 ⁻³ to 30 × 10 ⁻³ is a stretching temperature of 55 to 85 ° C., more preferably 60 to 80 ° C., and still more preferably 65 to 75 ° C. This is a step of stretching the oriented film in one or two or more stages in the longitudinal direction of the film using the difference in peripheral speed between heating rolls, and the total stretching ratio is preferably 2 to 5 times, more preferably 2. 5 to 4 times.

  In addition, the widthwise stretching step in which the stretching ratio is 4 to 15 times refers to a film after stretching in the longitudinal direction that has been heated to a stretching temperature of 60 to 105 ° C, more preferably 65 to 100 ° C, and even more preferably 70 to 95 ° C. The film is gripped at both ends with a clip and guided to a tenter, and stretched in the width direction. The stretching ratio is preferably 2.5 to 15 times, more preferably 4 to 15 times, still more preferably 5 to 10 Double is preferred.

  Here, the draw ratio is an effective draw ratio. For example, a 1 cm grid and a 10 cm × 10 cm size stamp are parallel to the film running direction at the center of the running film before stretching. It can be confirmed by pressing and measuring the average length of each square of the stamp remaining in the stretched film.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited thereto. Measurements and evaluations shown in the examples were performed under the following conditions.
[Measurement and evaluation method]
(1) Birefringence Δn
Using the sodium D line (wavelength 589 nm) as a light source, the refractive indexes (Nx and Ny) in the film longitudinal direction and width direction were measured by an Abbe refractometer, respectively, and calculated by the following equations. Note that methyl salicylate was used as the mounting solution. The measurement was in accordance with method A of JIS K 7142 (1996).

Δn = Nx−Ny
(2) Cut the heat shrinkage film in the width direction × longitudinal direction = 300 mm × 10 mm, draw a marked line at 200 mm intervals (l ₀ ) on the sample, hang a 3 g weight, and heat in a hot air oven heated to 120 ° C. Heat treatment was performed for 30 minutes. The distance (1) between the marked lines after the heat treatment was measured, and the thermal contraction rate was calculated from the change in the distance between the marked lines before and after heating by the following equation. The measurement was carried out by 5 samples and evaluated by an average value.

Thermal contraction rate = (l ₀ −l) / l × 100
(3) Stress at 2% elongation at 23 ° C. (F-2 value)
Stress-strain measurement at 23 ° C. was performed using TENSILON UCT-100 manufactured by Orientec Corp. equipped with a thermostatic bath. The sample was cut into a strip shape having a length of 200 mm and a width of 10 mm in the measurement direction, measured according to the method defined in JIS K 7127 (1999), and at the time of 2% elongation in the film longitudinal direction and the width direction at 120 ° C. The stress was determined. The distance between the initial tensile chucks was 30 mm, and the tensile speed was 300 mm / min. The sample was changed 20 times and the average value was used.
(4) Water vapor transmission rate Water vapor transmission rate measurement device (model name, “Permatran” (registered trademark) W3 / 31 manufactured by MOCON, USA) under conditions of a temperature of 40 ° C. and a humidity of 90% RH ) Was measured based on Method B (infrared sensor method) described in JIS K7129 (2000). Moreover, evaluation was performed about the raw film and the vapor deposition film. The measurement regarding the vapor deposition film was performed by applying a water vapor flow from the vapor deposition layer side and detecting on the opposite side of the vapor deposition layer. The measurement was performed twice, and was obtained from the average of two measured values.

(5) The film was slit to a width of 1000 mm with a slitting leather cutter type slitter, and the whiskers generated at that time were evaluated by the following methods. The slitter speed was 80 m / min.
The end face of the beard evaluation film was observed with a scanning electron microscope, and the occurrence of beard was evaluated according to the following criteria. In addition, the beard here means the film piece which peeled in the fiber form.
○ (good): There is almost no generation of beards △ (possible): little generation of beards x (not possible): many occurrences of beards (6) Optical density (OD)
Using an optical densitometer (TR927 manufactured by Gretag Macbeth Co., Ltd.), it was calculated from the following formula.

OD = log (I ₀ / I)
However, the incident light intensity of the sample is I ₀ and the transmitted light intensity is I.

(7) Heat of fusion (ΔH)
Based on JIS K 7122 (1987), a differential scanning calorimeter “Robot DSC-RDC-220” manufactured by Seiko Denshi Kogyo Co., Ltd. was used, and a disk session “SSC / 5200” was used for data analysis. Obtained when 5 mg of the resin composition scraped from layer B of the laminated film is sealed in an aluminum pan, set in the apparatus, and heated from 25 ° C. to 220 ° C. at a rate of 20 ° C./min in a nitrogen atmosphere. In the calorimetric curve, the area of the exothermic peak accompanying the melting of the crystal was obtained with the baseline as a straight line, and was taken as ΔH (J / g).

(8) Adhesion strength of the deposited layer (g / 15mm)
The vapor deposition film obtained by forming the vapor deposition layer on the film of the present invention and the unstretched polypropylene film (CPP) were aligned in the longitudinal direction, and dry laminated under the following conditions.
・ CPP: Toray Film Processing Co., Ltd. # 60 ZK93KM
・ Adhesive: Toyo Morton Co., Ltd. AD503 / cat10
-Blending amount: AD503 / cat10 / ethyl acetate = 20/1/20 parts by weight-Application: Use Metabar # 12, apply an adhesive on the corona-treated surface side of CPP, laminate to vapor-deposited film, and dry: 80 ° C , 45 seconds / curing: 40 ° C., 48 hours The sample obtained was subjected to a peel test under the following conditions, and the average of the lower limit values was read to measure the adhesion of the deposited layer.
・ Peel tester: Tensile Seiki Seisakusho tensile tester ・ Peel angle: 90 °
・ Peeling speed: 200 mm / min ・ Chart speed: 20 mm / min ・ Peeling direction: Longitudinal direction ・ Sample width: 15 mm
The same measurement was repeated three times, and the average value of the obtained values was defined as the adhesion (g / 15 mm) of the deposited layer.
[Polylactic acid resin]
It shows about the polylactic acid-type resin used in the Example.

P-1: Poly L-lactic acid resin having a D-lactic acid unit content ratio of 1 mol% and a PMMA equivalent weight average molecular weight of 190,000 P-2: Polylactic acid 4060D made by Nature Works having a D-lactic acid unit content ratio of 12 mol% Using.
[Stretching aid]
It shows about the extending | stretching adjuvant used in the Example.

Q-1: Polylactic acid-polyether block copolymer Production conditions for Q-1 are described below. 0.05 parts by mass of tin octylate is mixed with 70 parts by mass of polypropylene glycol having a weight average molecular weight of 10,000 and 30 parts by mass of L-lactide, and the mixture is stirred at 150 ° C. for 2 hours in a nitrogen atmosphere in a reaction vessel equipped with a stirrer. Polymerized. Polypropylene glycol and polylactic acid triblock copolymer Q-1 having a polylactic acid segment having a weight average molecular weight of 2,000 was obtained. The obtained block copolymer had a weight average molecular weight (Mw) in terms of PMMA measured by GPC of 14,000 and a glass transition temperature of 55 ° C.

  The glass transition temperature was measured by weighing approximately 5 mg of the dried film, filling it into a predetermined sample pan, and using a differential scanning calorimeter (DSC) RDC220 manufactured by Seiko Denshi Kogyo JIS K 7121. (1999), the glass transition temperature of the thermogram film when the temperature was raised at a rate of temperature rise of 20 ° C./min was determined.

Q-2: As a polylactic acid-polyester block copolymer Q-2, Plamate PD-150 manufactured by Dainippon Ink & Chemicals, Inc. was used.

Q-3: Biomax Strong 120 manufactured by DuPont was used as the olefin-acrylate copolymer polymer Q-3.

Table 1 shows the film forming conditions.
Example 1
Q-1 was added to P-1 using a known twin-screw extruder, and kneaded at 200 ° C. to obtain pellets.

  The obtained pellets were dried under reduced pressure at 120 ° C. for 5 hours under a vacuum of 5 torr, then supplied to an extruder, extruded into a film at a T die die temperature of 200 ° C., and cast onto a drum cooled to 10 ° C. Thus, an unstretched film was produced.

  This unstretched film was stretched 3.0 times in the longitudinal direction at a temperature of 70 ° C. by a roll-type stretching machine. After this uniaxially stretched film was once cooled on a cooling roll, both ends were held with clips and guided into a tenter, and stretched 8.0 times at a temperature of 90 ° C. in the width direction. Subsequently, after heat treatment at a temperature of 120 ° C. for 10 seconds under a constant length, a relaxation treatment of 10% in the width direction was performed at the same temperature to obtain a biaxially stretched polylactic acid film having a thickness of 20 μm.

In addition, about the film which measures the water-vapor-permeation rate after metal vapor deposition, 30 W * min / m, keeping a film temperature at 60 degreeC in the mixed gas (carbon dioxide gas concentration ratio 15 volume%) atmosphere of nitrogen and a carbon dioxide gas. ² was subjected to corona discharge treatment on one side and wound up. A film roll is set in a vacuum deposition apparatus equipped with a film traveling device, and after being brought to a high vacuum state of 1.00 × 10 ⁻² Pa, it is caused to travel through a cooling metal drum at 20 ° C. to heat and evaporate aluminum metal. A vapor-deposited thin film layer was formed and controlled to have an optical density of 2.5.

After vapor deposition, the inside of the vacuum vapor deposition apparatus was returned to normal pressure, and the wound film was rolled back and aged at a temperature of 40 ° C. for 2 days to obtain a vapor deposited film. The obtained film was a film excellent in water vapor barrier property and slit property.
(Example 2)
A biaxially stretched polylactic acid film was obtained in the same manner as in Example 1 except that the addition amount of the stretching aid and the lateral stretching ratio were changed.

The obtained film was a film excellent in water vapor barrier property and slit property.
(Example 3)
A biaxially stretched polylactic acid film was obtained in the same manner as in Example 2 except that the stretching aid was changed to Q-2.

The obtained film was a film excellent in water vapor barrier property and slit property.
Example 4
A biaxially stretched polylactic acid film was obtained in the same manner as in Example 2 except that the stretching aid was changed to Q-3.

The obtained film was a film excellent in water vapor barrier property and slit property.
(Example 5)
A biaxially stretched polylactic acid film was obtained in the same manner as in Example 2 except that the heat set temperature was changed.

The obtained film was a film excellent in water vapor barrier property and slit property.
(Example 6)
A biaxially stretched polylactic acid film was obtained in the same manner as in Example 1 except that the transverse stretch ratio, heat set temperature, and relaxation were changed.

The obtained film was a film excellent in water vapor barrier property and slit property.
(Example 7)
A biaxially stretched polylactic acid film was obtained in the same manner as in Example 2 except that the transverse stretch ratio and the heat set temperature were changed.

The obtained film was a film excellent in water vapor barrier property and slit property.
(Example 8)
A biaxially stretched polylactic acid film was obtained in the same manner as in Example 4 except that the raw material composition of the polylactic acid / stretching aid, the transverse stretch ratio, and the heat set temperature were changed.

The obtained film was a film excellent in water vapor barrier property and slit property.
(Comparative Example 1)
A biaxially stretched polylactic acid film was obtained in the same manner as in Example 1 except that the film composition and the transverse stretch ratio / temperature were changed.

The obtained film was inferior in water vapor barrier property and slit property as compared with Example 1.
(Comparative Example 2)
A biaxially stretched polylactic acid film was produced in the same manner as in Comparative Example 1 except for the transverse stretch ratio and temperature. However, since the transverse high-magnification stretching was performed without adding a stretching aid under these conditions, the film was broken during the transverse stretching. Frequent occurrence and film formation was impossible.
(Comparative Example 3)
A biaxially stretched polylactic acid film was obtained in the same manner as in Example 1 except that heat setting and relaxation treatment were not added.

The obtained film was inferior in water vapor barrier property and slit property as compared with Example 1. This is considered to be due to the fact that the thermal shrinkage rate deviated from the present application and the thermal shrinkage after the deposition became large.
(Comparative Example 4)
0.06 parts by weight of aggregated silica particles having an average particle diameter of 2.5 μm was added to 100 parts by weight of P-1 using a known twin-screw extruder, and kneaded at 200 ° C. to obtain pellets.

  The obtained pellets were dried under reduced pressure at 100 ° C. for 5 hours under a vacuum of 5 torr, then supplied to an extruder heated to 210 ° C., extruded into a sheet at a T die die temperature of 210 ° C., and a surface temperature of 20 ° C. An unstretched film having a thickness of 380 μm was obtained by casting on a drum.

  This unstretched film was preheated to a film temperature of 70 ° C. by a plurality of ceramic rolls, and stretched three times in the machine direction so that the stretching speed was 30000% / min between two rolls having different peripheral speed differences. Next, after this uniaxially stretched film was once cooled on a cooling roll, both ends were held with clips and guided into a tenter, preheated to 68 ° C., and then stretched 6.5 times in the width direction at 80 ° C. Subsequently, after heat treatment at 155 ° C. for 15 seconds under a constant length, 3% relaxation treatment was performed in the width direction at 120 ° C., and an attempt was made to produce a 20 μm-thick biaxially stretched polylactic acid film (implementation disclosed in Reference 3) Example 1 supplementary test).

  However, film tearing frequently occurred in the transverse stretching process, and the film formation was extremely unstable. For this reason, a satisfactory sample was not obtained.

  Next, the case where B layer is laminated | stacked on one side of the aliphatic polyester-type polylactic acid film of this invention as an easily bonding layer is shown.

Example 9
45 parts by weight of P-1, 45 parts by weight of P-2 and 10 parts by weight of Q-1 were mixed and kneaded at 200 ° C. using a known twin screw extruder to obtain pellets. The obtained pellets were dried under reduced pressure at 100 ° C. for 5 hours under a vacuum of 5 torr to obtain a raw material used for the B layer.

  The resin composition used in Example 1 was supplied to an extruder A heated to 200 ° C., and the polymer was filtered with a filter obtained by sintering and compressing stainless steel fibers having an average opening of 12 μm. Separately, the above raw materials were supplied to an extruder B heated to 200 ° C., and the polymer was filtered with a sintered filter having an average opening of 25 μm. The polymer from both extruders is laminated with a multilayer die so that the A / B layer thickness structure after biaxial stretching is 3/17 μm, and cast on a drum cooled to 25 ° C. to produce an unstretched film did.

  The obtained unstretched film was continuously stretched 3 times in a longitudinal direction at a temperature of 70 ° C. by a roll type stretching machine. After this uniaxially stretched film was once cooled on a cooling roll, both ends were held with clips and guided into a tenter, and stretched 10 times at a temperature of 90 ° C. in the sailing direction. Subsequently, after a heat treatment at a temperature of 130 ° C. for 10 seconds under a constant length, a relaxation treatment of 10% in the width direction was performed at the same temperature to obtain a biaxially stretched polylactic acid film having a thickness of 20 μm.

  A vapor-deposited film was obtained by forming a vapor-deposited layer on the B layer in the same manner as in Example 1 for the obtained biaxially stretched polylactic acid film.

  The obtained film was a film excellent in water vapor barrier property and slit property. Moreover, the vapor deposition film vapor-deposited on B layer showed high adhesive force.

(Example 10)
28.5 parts by weight of P-1, 66.5 parts by weight of P-2, and 5 parts by weight of Q-3 were mixed and kneaded at 200 ° C. using a known twin screw extruder to form pellets, 50 ° C. , 12 hours, vacuum dried at 5 torr as a raw material to be used for the B layer, supplied to the extruder B, the same as in Example 9 except that the raw material composition of the A layer was changed as shown in the table Thus, a biaxially stretched polylactic acid film and a vapor-deposited film thereof were obtained.

The obtained film was a film excellent in water vapor barrier property and slit property. Moreover, the vapor deposition film vapor-deposited on B layer showed high adhesive force.
(Example 11)
95 parts by weight of P-2 and 5 parts by weight of Q-1 were mixed and kneaded at 200 ° C. using a known twin screw extruder to form pellets, which were dried under reduced pressure at 50 ° C. for 12 hours under a vacuum of 5 torr. A biaxially stretched polylactic acid film and its vapor-deposited film were obtained in the same manner as in Example 9 except that the raw material used for the B layer was supplied to the extruder B.

The obtained film was a film excellent in water vapor barrier property and slit property. Moreover, the vapor deposition film vapor-deposited on B layer showed high adhesive force.
Example 12
A biaxially stretched polylactic acid film and its vapor-deposited film were obtained in the same manner as in Example 10 except that Q-3 was not used as the raw material for the B layer and the transverse stretch ratio and the heat set temperature were changed.

The obtained film was a film excellent in water vapor barrier property and slit property. Moreover, the vapor deposition film vapor-deposited on B layer showed high adhesive force.
(Example 13)
As a raw material for the B layer, biaxially stretched polylactic acid was used in the same manner as in Example 9 except that P-2 was dried under reduced pressure at 50 ° C. for 12 hours under a vacuum of 5 torr, and the transverse stretch ratio and the heat set temperature were changed. A film and its deposited film were obtained.

The obtained film was a film excellent in water vapor barrier property and slit property. Moreover, the vapor deposition film vapor-deposited on B layer showed high adhesive force.
(Example 14)
63 parts by weight of P-1, 27 parts by weight of P-2, and 10 parts by weight of Q-2 were mixed and kneaded at 200 ° C. using a known twin screw extruder to form pellets, 100 ° C. for 5 hours, A biaxially stretched polylactic acid film and its vapor-deposited film were obtained in the same manner as in Example 9 except that the material used for layer B was dried under reduced pressure under a vacuum of 5 torr, and the material composition of layer A and the transverse stretch ratio were changed. It was.

The obtained film was a film excellent in water vapor barrier property and slit property. Moreover, the vapor deposition film vapor-deposited on B layer showed high adhesive force.
(Example 15)
The film of Example 2 was directly used as the biaxially stretched polylactic acid film of Example 15.

The obtained film was a film excellent in water vapor barrier property and slit property although the adhesion of the deposited layer was low.
(Comparative Example 5)
The film of Comparative Example 1 was used as the biaxially stretched polylactic acid film of Comparative Example 6 as it was.

  The obtained film was inferior in water vapor | steam barrier property and slit property, and inferior in the adhesive force of the vapor deposition layer.

  The aliphatic polyester film and laminated film of the present invention are excellent in production stability even when stretched at a high horizontal magnification, so that they are excellent in productivity, slit property, edge appearance at room temperature storage, and water vapor barrier properties. It can be preferably used for various packaging materials used for foods and the like, and various industrial materials.

Claims (8)

Δn is −30 × 10 ⁻³ to −5 × 10 ⁻³ ,
The shrinkage rate in the film width direction after heating at 120 ° C. for 30 minutes is −30% to 30%,
The total amount of aliphatic polyester and stretching aid is 50% by mass or more and 100% by mass or less with respect to 100% by mass of all components of the film,
A fat comprising 60% to 99.9% by weight of an aliphatic polyester and 0.1 to 40% by weight of a stretching aid with respect to 100% by weight of the total amount of the aliphatic polyester and the stretching aid. Group polyester film.
However,
Δn: (refractive index in the film longitudinal direction) − (refractive index in the film width direction)   The aliphatic polyester film according to claim 1, wherein the aliphatic polyester is polylactic acid.   The stretching aid is at least one selected from a polylactic acid-polyether block copolymer, a polylactic acid-polyester block copolymer, and an olefin acrylate copolymer polymer. 2. The aliphatic polyester film according to 2. F-2 value in the film longitudinal direction is 30 to 100 MPa, F-2 value in the film width direction is 80 to 150 MPa,
The aliphatic polyester film according to any one of claims 1 to 3, wherein the F-2 value in the film longitudinal direction is smaller than the F-2 value in the film width direction. A laminated film having a B layer on at least one side of the A layer,
The A layer is an aliphatic polyester film, and contains 50% by mass to 100% by mass of the aliphatic polyester and the stretching aid with respect to 100% by mass of all components of the A layer. 60 mass% to 99.9 mass% of aliphatic polyester and 0.1 to 40 mass% of stretching aid are contained with respect to 100 mass% of the total amount of polyester and stretching aid,
The B layer is an aliphatic polyester film, and the heat of fusion (ΔH) of the B layer is 0 to 40 J / g.
Laminated film, characterized in that Δn is ^{-30 × 10 -3 ~-5 ×} 10 -3, shrinkage of the film width direction after 30 minutes heating at 120 ° C. is 30% or less than -30%, Laminated film.
However,
Δn: (refractive index in the film longitudinal direction) − (refractive index in the film width direction)   The laminated film according to claim 5, wherein the aliphatic polyester of the A layer is polylactic acid. The B layer contains polylactic acid and a stretching aid,
In 100% by mass of all components of the B layer, 70% by mass or more is polylactic acid,
The laminated film according to claim 5 or 6, comprising 0.5 to 20 mass% of a stretching aid with respect to 100 mass% of the total amount of polylactic acid and stretching aid of the B layer. A longitudinal stretching step in which Δn is 5 × 10 ⁻³ to 30 × 10 ⁻³ ,
And having a width direction stretching step in which the stretching ratio is 4 to 15 times in this order,
Characterized in that Δn is ^{-30 × 10 -3 ~-5 ×} 10 -3, shrinkage of the film width direction of 30 minutes after heating at 120 ° C. is 30% or less than -30%, the aliphatic polyester A method for producing a film.