JP2013147580A - Polylactic acid-based oriented film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polylactic acid-based oriented film excellent in a gas barrier property and silence.SOLUTION: A polylactic acid-based oriented film mainly consists of a polylactic acid-based resin, and is characterized in that the value of a noise level measured by a method defined by the present specification is at most 85 dB, and the water vapor permeability is at most 2.0 g/m/day.

Description

  The present invention relates to a polylactic acid oriented film having excellent gas barrier properties and quietness.

  In recent years, due to increasing awareness of environmental issues, attention has been focused on soil pollution problems caused by the disposal of plastic products and global warming problems caused by increased carbon dioxide caused by incineration. As a measure against the former, various biodegradable resins, and as a measure against the latter, a resin made of biomass (plant-derived raw material) that does not give a new carbon dioxide load to the atmosphere even if it is incinerated has been extensively researched and developed. ing.

  One example of a resin that satisfies the above-described characteristics is polylactic acid. Polylactic acid has a high melting point and is expected to be a practically excellent biodegradable polymer that can be melt-molded. For example, a polylactic acid film is said to have the highest tensile strength and elastic modulus among various biodegradable films, and is excellent in gloss and transparency.

  At present, the use of polylactic acid film is expanding, but among them, it is particularly suitable for packaging materials. When used as part of a film of packaging material, higher functionality is required as a single film in order to be able to produce a commercially effective and cost-effective packaging product. For example, it may be heat sealability required for processing into a molded body or gas barrier properties when a vapor deposition layer is provided. In particular, regarding gas barrier properties, a very high level has recently been required. In addition, among packaging materials, when used for applications where there are many opportunities to touch or bend it for snack packaging or the like, the quietness of the film has been required. However, polylactic acid film is hard and brittle compared to other packaging thermoplastic resin films represented by polyolefin, and when external stress such as stagnation and bending is applied, There is a problem of emitting a peculiar harsh sound. Therefore, a polylactic acid film having practical film properties and excellent gas barrier properties and quietness is desired.

  Various attempts have been made to solve the above requirements. For example, Patent Documents 1, 2, and 3 disclose a film obtained by adding a plasticizer to a polylactic acid-based resin in order to improve the properties of a polylactic acid film that is hard and brittle and to provide quietness. However, all of them are intended for use in OPP and soft vinyl chloride substitute applications (for example, stretch films for food packaging, wrap films for food packaging, agricultural films, industrial protective films, etc.) Even though a technical study for imparting quietness has been made, a technical idea of imparting a high level of gas barrier property is not disclosed, and there is no suggestion for a solution. On the other hand, Patent Document 4 discloses a biaxially stretched polylactic acid-based film obtained by blending an amorphous polylactic acid-based resin and a crystalline polylactic acid-based resin as a solution for gas barrier property improvement. Although this has been improved with respect to gas barrier properties, it does not describe a solution for the film quietness problem of making an unpleasant sound peculiar to polylactic acid films, and furthermore, a method for achieving both quietness and high gas barrier properties. Is not disclosed.

Japanese Patent No. 4452014 JP 2008-138102 A JP 2004-143432 A International Publication No. 2010/111501

  Then, this invention is made | formed in view of the said problem, and it aims at providing the polylactic acid-type oriented film which has the outstanding silence and also has gas barrier property.

In order to solve the above problems, the present invention has the following configuration. That is,
(1) A polylactic acid oriented film comprising a polylactic acid resin as a main component, having a noise level value of 85 dB or less and a water vapor permeability of 2.0 g / m ² / day or less.
(2) The polylactic acid according to (1), wherein a vapor deposition layer, an A1 layer mainly composed of an amorphous polylactic acid resin, and a B layer mainly composed of a polylactic acid resin are laminated in this order. System oriented film.
(3) A block copolymer having a polyether segment and a polylactic acid segment, a block copolymer having a polyester segment and a polylactic acid segment, and an aliphatic polyester in 100% by mass of all components of the B layer 4 to 40% by mass of at least one resin selected from the group consisting of an aliphatic resin (excluding polylactic acid resin) and an aliphatic aromatic polyester resin (hereinafter referred to as a flexible resin). The polylactic acid oriented film according to (2).
(4) A deposited layer, an A1 layer mainly composed of an amorphous polylactic acid resin, a B layer mainly composed of a polylactic acid resin, and an A2 layer mainly composed of an amorphous polylactic acid resin in this order. The thickness of the A1 layer is 2 μm or less, the thickness of the A2 layer is 2 μm or more, and (the total thickness of the A1 layer and the A2 layer) / (the total thickness of the B layer) ≦ 0. 5. The polylactic acid-based oriented film according to any one of (1) to (3), which is 5.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the polylactic acid-type oriented film which has the outstanding silence which was not able to be achieved by the prior art, and also has gas barrier property. The film of the present invention can be suitably used for snack packaging applications that require a very high level of gas barrier properties.

  Hereinafter, the present invention will be described in detail together with preferred embodiments.

  The film of the present invention mainly comprises a polylactic acid resin. Here, having a polylactic acid-based resin as a main component means that the polylactic acid-based resin is the largest in mass in all the components constituting the film. From the viewpoint of biodegradability and biomass properties, the content of the polylactic acid-based resin is preferably 50% by mass or more and 100% by mass or less, more preferably 55% by mass or more and 100% by mass with respect to 100% by mass of all components of the B layer. % Or less, more preferably 60% by mass or more and 100% by mass or less.

  The polylactic acid-based resin in the present invention means a polymer containing D-lactic acid and / or L-lactic acid as a main constituent component. In addition, the polylactic acid resin may contain a comonomer component other than lactic acid. Examples of the comonomer component include ethylene glycol, propylene glycol, butanediol, heptanediol, hexanediol, octanediol, nonanediol, decanediol, 1,4-cyclohexanedimethanol, neopentylglycol, glycerin, Glycol compounds such as pentaerythritol, 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, terephthalate Acid, isophthalic acid, phthalic acid, naphthalene dicarboxylic acid, bis (p-carboxyphenyl) methane, anthracene dicarboxylic acid, 4,4'-diphenyl ether di Dicarboxylic acids such as rubonic acid, 5-sodium sulfoisophthalic acid and 5-tetrabutylphosphonium isophthalic acid, glycolic acid, hydroxypropionic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxycaproic acid, hydroxybenzoic acid and other hydroxycarboxylic acids, caprolactone And lactones such as valerolactone, propiolactone, undecalactone, and 1,5-oxepan-2-one.

  The polylactic acid-based oriented film of the present invention preferably contains a flexible resin in order to improve the hard and brittle nature of the polylactic acid film and to provide quietness. The flexible resin here is a block copolymer having a polyether segment and a polylactic acid segment, a block copolymer having a polyester segment and a polylactic acid segment, an aliphatic polyester resin (polylactic acid-based resin). And at least one resin selected from the group consisting of aliphatic aromatic polyester resins. Also, from the viewpoint of suppressing bleed out, it is important to use a flexible resin of a polymer type, and this flexible resin is contained in the B layer in consideration of gas barrier properties and deposited film adhesion when a deposited layer is applied. It is preferable.

First, a block copolymer having a polyether segment and a polylactic acid segment and a block copolymer having a polyester segment and a polylactic acid segment will be described below. (Hereinafter referred to as “block copolymer plasticizer”)
The mass ratio of the polylactic acid segment contained in the block copolymer plasticizer is preferably 50% by mass or less of the entire block copolymer plasticizer, since a desired silentness can be imparted with a smaller amount of addition, preferably 5 mass. % Or more is preferable from the viewpoint of suppressing bleed-out. The number average molecular weight of the polylactic acid segment in one molecule of the block copolymer plasticizer is preferably 1,200 to 10,000. When the polylactic acid segment of the block copolymer plasticizer is 1,200 or more, sufficient affinity is produced between the block copolymer plasticizer and the polylactic acid resin, and a part of the segment Is incorporated into crystals formed from polylactic acid-based resins, and forms so-called eutectics, thereby causing the block copolymer plasticizer to bind to the polylactic acid-based resin, resulting in a bleedout of the block copolymer plasticizer. It has a great effect on suppression. The number average molecular weight of the polylactic acid segment of the block copolymer plasticizer is more preferably 1,500 to 6,000, and further preferably 2,000 to 5,000. In addition, the polylactic acid segment which the block copolymer plasticizer has is that L-lactic acid is 95 to 100% by mass or D-lactic acid is 95 to 100% by mass. Therefore, it is preferable.

  The block copolymer plasticizer has a polyether-based and / or polyester-based segment, but the block copolymer having a polyether-based segment and a polylactic acid segment has a desired quietness with a small amount of addition. It is preferable from a viewpoint which can provide. Furthermore, in the block copolymer having a polyether-based segment and a polylactic acid segment, it is more preferable to have a segment made of a polyalkylene ether as a polyether-based segment from the viewpoint of imparting a desired quietness with a smaller amount of addition. preferable. Specifically, examples of the polyether-based segment include a segment made of polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyethylene glycol / polypropylene glycol copolymer, etc., and in particular, a segment made of polyethylene glycol is a polylactic acid-based segment. Since the affinity with the resin is high, the modification efficiency is excellent. In particular, the addition of a small amount of a block copolymer plasticizer can provide desired silentness, which is preferable.

  When the block copolymer plasticizer has a polyester-based segment, polyglycolic acid, poly (3-hydroxybutyrate), poly (3-hydroxybutyrate · 3-hydroxyvalerate), polycaprolactone, or ethylene glycol, Polyesters composed of aliphatic diols such as propanediol and butanediol and aliphatic dicarboxylic acids such as succinic acid, sebacic acid and adipic acid are preferably used as the polyester segment.

  The block copolymer plasticizer may contain both components of the polyether segment and the polyester segment in one molecule, or may be either one of the components. For reasons of plasticizer productivity, cost, etc., when using any one component, it is preferable to use a polyether-based segment from the viewpoint that desired silence can be imparted by adding a smaller amount of plasticizer. That is, a preferred embodiment as a block copolymer plasticizer is a block copolymer of a polyether segment and a polylactic acid segment.

  Furthermore, the number average molecular weight of the polyether segment or the polyester segment in one molecule of the block copolymer plasticizer is preferably 7,000 to 20,000. By setting it as the above range, it is possible to provide sufficient silence.

  There is no particular limitation on the order configuration of each segment block of the polyether-based and / or polyester-based segment and the polylactic acid segment, but at least one block of the polylactic acid segment is blocked from the viewpoint of more effectively suppressing bleed out. It is preferably at the end of the copolymer plasticizer molecule.

  Next, the case where polyethylene glycol having a hydroxyl terminal at both ends (hereinafter, polyethylene glycol is referred to as PEG) is employed as the polyether segment will be specifically described.

The number average molecular weight of PEG having hydroxyl ends at both ends (hereinafter, the number average molecular weight of _PEG is referred to as _MPEG ) is usually calculated from the hydroxyl value determined by a neutralization method or the like in the case of a commercially available product. In a system in which lactide w _L parts by mass are added to w _E parts by mass of PEG having hydroxyl groups at both ends, lactide is subjected to ring-opening addition polymerization at both hydroxyl groups of PEG and sufficiently reacted, so that PLA is substantially obtained. A block copolymer of the -PEG-PLA type can be obtained (PLA here indicates polylactic acid). This reaction is performed in the presence of a catalyst such as tin octylate as necessary. The number average molecular weight of one polylactic acid segment of this block copolymer plasticizer can be substantially determined as (1/2) × (w _L / w _E ) × M _PEG . The mass percentage of the total block copolymer plasticizer of the polylactic acid segment component can be substantially determined as _{100 × w L / (w L} + w E)%. Furthermore, the mass ratio of the plasticizer component excluding the polylactic acid segment component to the entire block copolymer plasticizer can be determined to be substantially 100 × w _E / (w _L + w _E )%.

  Examples of the aliphatic polyester other than the polylactic acid resin include polyglycolic acid, poly (3-hydroxybutyrate), poly (3-hydroxybutyrate · 3-hydroxyvalerate), polycaprolactone, or ethylene glycol. An aliphatic polyester comprising an aliphatic diol such as 1,4-butanediol and an aliphatic dicarboxylic acid such as succinic acid or adipic acid is preferably used.

  Further, as the aliphatic aromatic polyester, for example, polybutylene succinate, polybutylene succinate adipate, polybutylene adipate terephthalate and the like are preferably used.

  Among the aliphatic polyesters and aliphatic aromatic polyesters, polybutylene adipate terephthalate, polybutylene succinate, and polybutylene succinate are preferred because they have excellent stretchability when added and have a large effect of improving silence. Nate adipate and at least one selected from the group consisting of poly (3-hydroxybutyrate · 3-hydroxyvalerate) are more preferably used.

  The flexible resin contained in the polylactic acid-based oriented film of the present invention is preferably 4% by mass or more and 40% by mass or less in 100% by mass of all components of the B layer, and within the range not impairing the effect of the present invention. It is also possible to use a plurality of types of the flexible resins together. If the total content of the flexible resin is less than 4% by mass, it is not preferable because it is difficult to obtain the effect of improving the film silence. If more than 40% by mass, it is preferable from the viewpoint of improving the silence of the film. In consideration of film-forming stability, film flatness, and handleability in post-processing processes such as vapor deposition, it is not preferable.

  The polylactic acid oriented film of the present invention may have an arbitrary layer configuration as long as the effects of the present invention are not impaired. Examples of the layer configuration include A1 layer / B layer, A1 layer / B layer / A2 layer, and the like. Is mentioned. The A1 layer means a layer mainly composed of an amorphous polylactic acid resin, the B layer means a layer mainly composed of a polylactic acid resin, and the A2 layer means an amorphous property. Means a layer mainly composed of a polylactic acid-based resin. The A1 layer and the A2 layer are preferably a vapor deposition receiving layer and a heat seal layer, respectively. The term “main body” as used herein means that the specific resin is 50% by mass or more and 100% by mass or less in the total component of 100% by mass of the specific layer.

The polylactic acid resin in the B layer is preferably a mixture of a crystalline polylactic acid resin and an amorphous polylactic acid resin, but the intended use / characteristics of the film of the present invention and the flexible resin to be added It is important to adjust these proportions depending on the type. For example, when the block copolymer plasticizer is contained in the B layer as the above-mentioned flexible resin, an amorphous polylactic acid-based resin is used to improve the bleed-out resistance and provide an amorphous part in which the flexible resin can be dispersed. It is preferable that many are included. When the amount of the resin in the composition constituting the B layer is 100% by mass (when the total of the crystalline polylactic acid resin and the amorphous polylactic acid resin is 100% by mass), the amorphous polylactic acid The proportion of the system resin is preferably 50% by mass or more and 80% by mass or less, more preferably 55% by mass or more and 80% by mass or less, and further preferably 60% by mass or more and 80% by mass or less.

In addition, for example, when a resin other than the block copolymer plasticizer is contained in the B layer as the flexible resin, the inclusion of the crystalline polylactic acid resin and the amorphous polylactic acid resin unless the effects of the present invention are impaired. The ratio of the amount is not particularly limited, but in the biaxial stretching process and in downstream processing processes such as laminating and bag forming, when the mechanical properties and rigidity to heat treatment, flatness and durability are important, It is preferable that a large amount of lactic acid resin is contained. More specifically, the content of the crystalline polylactic acid resin in the B layer is more specifically 100% by mass of the polylactic acid resin in the B layer (the total of the crystalline polylactic acid resin and the amorphous polylactic acid resin is The ratio of the crystalline polylactic acid resin is preferably 30% by mass or more and 80% by mass or less, more preferably 40% by mass or more and 80% by mass or less, and 50% by mass. More preferably, it is 80 mass% or less.

  In order to make the polylactic acid resin crystalline, the mass ratio of D-lactic acid and L-lactic acid in the polylactic acid resin is preferably 0: 100 to 10:90. Even if the polylactic acid resin essentially contains only L-lactic acid, it will not be a serious problem, but if the amount of the crystalline polylactic acid resin is too large, the film production process will be poor. Therefore, a more preferable mass ratio of D-lactic acid and L-lactic acid is 1:99 to 5:95, and a more preferable mass ratio is 2:98 to 4:96.

  The crystalline polylactic acid resin referred to in the present invention is measured by a differential scanning calorimeter (DSC) in a temperature range of 25 ° C. to 250 ° C. after the polylactic acid resin is sufficiently crystallized under heating. When performed, it refers to a polylactic acid resin in which the heat of crystal melting derived from the polylactic acid component is observed. On the other hand, the amorphous polylactic acid-based resin referred to in the present invention refers to a polylactic acid-based resin that does not exhibit a clear melting point when measured in the same manner.

  Preferable examples of the crystalline polylactic acid resin used for the B layer include, for example, Ingeo (trademark) 4032D (D-lactic acid = 1.4 mol%), 4042D (D-lactic acid = 4. 2 mol%). The D-L ratio can be adjusted to a predetermined level by mixing these components or by mixing with a brand having a high D component ratio such as Ingeo ™ 4060D (D-lactic acid = 12 mol%).

  In order to make the polylactic acid resin amorphous, the content ratio of D-lactic acid and L-lactic acid in the polylactic acid resin is 10:90 to 15:85, preferably 11:89 to 13:87. It is preferable that Preferable examples of the amorphous polylactic acid resin used for the B layer include, for example, Ingeo (trademark) 4060D (D-lactic acid = 12 mol%) manufactured by NatureWorks (registered trademark).

  On the other hand, in order to impart stretchability, moldability, adhesion to the vapor deposition layer when the vapor deposition layer is applied to the film, and gas barrier properties, the A layer is mainly composed of an amorphous polylactic acid resin. More specifically, the content of the amorphous polylactic acid resin in the A layer is 50% by mass to 100% by mass of the amorphous polylactic acid resin in 100% by mass of the polylactic acid resin in the A layer. It is preferable that it is below, More preferably, it is 55 to 100 mass%, More preferably, it is 60 to 100 mass%.

  Further, other thermoplastic resins may be mixed in the A layer and the B layer in a desired ratio within a range not impairing the effects of the present invention. Examples of other thermoplastic resins include ultra low density polyethylene, linear low density polyethylene, low density polyethylene, medium density polyethylene, high density polyethylene, polypropylene, ethylene / propylene rubber, ethylene / vinyl acetate copolymer, ethylene / vinyl acetate, Polyolefins such as acrylic acid ester copolymers and ionomers; Polyesters such as polyethylene terephthalate and polyethylene naphthalate; Polystyrene resins such as polystyrene, high-impact polystyrene, styrene / butylene / styrene block copolymers, and hydrogenation; Hard poly Polyvinyl chloride resins such as vinyl chloride and soft polyvinyl chloride; polycarbonate, polyamide, polyurethane, ethylene / vinyl alcohol copolymer, polyvinylidene chloride resin, acrylic resin, etc. are preferred . Among the other thermoplastic resins, an acrylic resin is preferable for imparting heat resistance, stretchability, and moldability to the film of the present invention, and in view of compatibility with the polylactic acid resin, polymethyl methacrylate is used. More preferably, it is used.

  The thickness of the polylactic acid oriented film of the present invention is not particularly limited, but is preferably 10 μm or more and 30 μm or less, more preferably 11 to 27 μm, and still more preferably from the viewpoint of handling properties when processed into a packaging material. Is 12-25 μm.

  The thickness of the vapor deposition receiving layer A1 is preferably 2.0 μm or less, more preferably 1.8 μm or less, and still more preferably 1.5 μm or less. When the thickness exceeds 2.0 μm, the planarity becomes poor due to heat applied in a post-processing process such as vapor deposition, and the water vapor barrier property, the oxygen barrier property, and the adhesion strength of the deposited film may be lowered.

  In contrast, the thickness of the heat seal layer A2 is preferably 2.0 μm or more in order to give excellent heat seal properties such as heat seal strength at a specific sealing temperature, but more than 1 μm or 1 It is also possible to use thinner layers, such as ˜1.5 μm. A suitable value of the allowable heat seal strength is 200 g / 25 mm or more at a seal temperature of 120 ° C. This can be easily obtained if the thickness of the A2 layer is 2.0 μm or more. When the thickness of the layer is too large, for example, 4 μm or more, a process failure such as the deterioration of the flatness of the film profile and the decrease of the thermal stability as described above may occur.

  It is preferable to adjust the relationship between the thicknesses of the A layer and the B layer in the present invention. When the total thickness of the A1 layer and the A2 layer is too large, or when the B layer is too thin, the flatness of the profile of the film is deteriorated and the thermal stability is lowered. Therefore, in particular, the polylactic acid oriented film of the present invention includes a vapor deposition layer, an A1 layer mainly composed of an amorphous polylactic acid resin, a B layer mainly composed of a polylactic acid resin, and an amorphous polylactic acid resin. In the case where the A2 layer mainly composed of is laminated in this order, the preferable range of (the total thickness of the A1 layer and the A2 layer / the total thickness of the B layer) is 0.5 or less. Preferably it is 0.3 or less, More preferably, it is 0.25 or less. When this ratio exceeds 0.5, the flatness of the film profile becomes poor due to heat applied in a post-processing process such as vapor deposition, and the thermal stability is lowered. In order to keep (the total thickness of the A1 layer and the A2 layer / the total thickness of the B layer) in a low range, the structure of the A1 layer and the A2 layer is made asymmetric (the thickness of the A1 layer and the A2 layer is reduced) It is also preferable to use different values.

  In order to impart preferable handling properties and functional friction coefficient properties to the film, the A layer may contain an inorganic or organic filler.

  The filler of the A layer preferably has an average particle size of 0.1 μm to 3 μm, more preferably 0.5 μm to 2 μm. Further, the content of the filler in the A layer is preferably 0.01% by mass to 0.3% by mass, more preferably 0.01% by mass to 0.1% by mass in 100% by mass of all the components of the A layer. is there. When the filler in the A layer is larger than 3 μm for the average particle size or larger than 0.3% by mass for the content, for example, when the deposited layer is formed on the A1 layer, too many large particles are used. A gas transfer property (for example, a scratch or a pinhole) may be generated on the vapor deposition layer by the protrusions, so that the gas barrier property may be impaired. The filler in the A layer is not particularly limited as long as the effects of the present invention are not impaired. However, since it exhibits good compatibility with the polylactic acid resin, aluminum silicate is used as the filler in the A layer. preferable. When aluminum silicate is used as the filler in the A layer, the compatibility between the polylactic acid resin, which is the main component of the A layer, and the aluminum silicate is excellent, so that it is difficult to form voids around the filler in the A layer. There is.

  The polylactic acid-based oriented film of the present invention can be added with an additive as long as the effects of the present invention are not impaired. Available additives include flame retardants, heat stabilizers, light stabilizers, antioxidants, hydrophobic substances, debonding agents, coupling agents, chain extenders, end group capping agents, oxygen absorbers, hygroscopic agents , Anti-coloring agents, ultraviolet absorbers, antistatic agents, plasticizers, nucleating agents, lubricants, adhesion improvers, pigments and the like.

  In order to impart gas barrier properties to the polylactic acid-based oriented film of the present invention, it is important to form a vapor deposition layer made of a metal or an inorganic oxide on the surface layer of the A1 layer. It is preferable that the polylactic acid-type film of this invention which has a vapor deposition layer is an aspect by which the vapor deposition layer, A1 layer, and B layer were laminated | stacked in this order. The metal or inorganic oxide used for the vapor deposition layer is not particularly limited, and examples thereof include aluminum, aluminum oxide, silicon oxide, silicon oxynitride, cerium oxide, calcium oxide, diamond-like carbon film, and a mixture thereof. Can be mentioned. In order to improve gas barrier properties while maintaining or improving productivity, aluminum, aluminum oxide, and silicon oxide are more preferably used. A vapor deposition layer using aluminum is preferable because it is excellent in economy and gas barrier performance, and a vapor deposition layer using aluminum oxide or silicon oxide is preferable in terms of cost and transparency.

In the vacuum process, the surface of the vapor deposition layer is preferably subjected to plasma treatment or corona treatment in order to further improve the gas barrier property. Processing strength when subjected to corona treatment is preferably 5～50W · min / ^{m 2,} more preferably a 10～45W · min / ^{m 2.} In addition, it is preferable to provide a cored metal vapor deposition layer under plasma discharge before providing a vapor deposition layer made of metal or an inorganic oxide from the viewpoint of improving the adhesion of the vapor deposition layer and, consequently, improving the gas barrier property. In this case, plasma discharge is preferably performed in an oxygen and / or nitrogen gas atmosphere, and copper is preferably used as the cored metal.

  The polylactic acid film of the present invention is a film stretched at least in a uniaxial direction from the viewpoint of imparting mechanical properties, heat resistance, and dimensional stability. The stretching direction may be either the longitudinal direction or the width direction of the film, but it is more preferable to perform biaxial stretching in both the longitudinal direction and the width direction of the film from the viewpoint of further improving the above characteristics. The stretching method is not particularly limited, and a known biaxial stretching method such as a sequential biaxial stretching method and a simultaneous biaxial stretching method, or a combination thereof can be used.

Below, the manufacturing method of the polylactic acid-type film of this invention directly laminated | stacked in this order with the 2 types 3 layer structure of A1 layer, B layer, and A2 layer is described. (A1 and A2 layers use the same resin)
Each extruder is melt-extruded with the resin composition used for layer A and layer B. After removing foreign matter with a wire mesh and optimizing the flow rate with a gear pump, it is supplied to a multi-manifold base or a feed block installed on the top of the base. To do. The multi-manifold base or the feed block needs to be provided with a desired number of channels having a desired shape in accordance with a required film layer configuration. The molten resin extruded from each extruder is merged by the multi-manifold die or the feed block as described above, and coextruded into a sheet form from the die. The sheet is brought into close contact with the casting drum by an air knife or a system such as electrostatic application, and is cooled and solidified to form an unstretched sheet.

  Here, in order to prevent surface roughness due to foreign matters such as gels and thermally deteriorated products, it is preferable to use a filter obtained by sintering and compressing stainless steel fibers having an average opening of 5 to 90 μm as a filter during film formation. Further, after the filter in which the stainless steel fiber is sintered and compressed, a filter in which a stainless steel powder having an average opening of 10 to 70 μm is sintered is continuously filtered in this order, or the two kinds of filters are put in one capsule. It is preferable to use a composite filter that is also used because gels and thermally deteriorated materials can be efficiently removed, and it is desirable because of the cost merit that the film forming edge and the core part can be reused.

  Next, in order to sequentially biaxially stretch the unstretched sheet thus obtained, the unstretched sheet is preheated by passing through a roll, and subsequently passed between rolls having a difference in peripheral speed, and stretched in the longitudinal direction. Immediately after cooling to room temperature, the longitudinally uniaxially stretched film is guided to a tenter and stretched in the transverse direction, and then it is heat-set while being relaxed in the transverse direction. In this way, the film of the present invention is produced.

  The longitudinal and lateral stretching temperatures of the film of the present invention are preferably from 60 to 100 ° C. from the viewpoint of obtaining a film having improved stretchability, flatness and mechanical properties. When the stretching temperature is less than 60 ° C., the film is broken, and when it exceeds 100 ° C., the stretchability is remarkably lowered, and it is difficult to obtain a film having good flatness. More preferably, it is 65-90 degreeC, More preferably, it is 70-85 degreeC. The stretching ratio is preferably 2.0 to 10.0 times, more preferably 2.2 to 8.0 times, and still more preferably 2.5 to 5.0 times for each of the longitudinal and lateral stretching. In addition, the stretching method is not particularly limited, and may be performed in a single stage, or may be performed in a multistage system by changing temperature, stretching ratio, stretching speed, and the like.

  In addition, after stretching, it is preferable to perform relaxation heat treatment and cool the film in order to impart desired mechanical properties and dimensional stability. The heat treatment temperature is preferably 70 to 180 ° C. or less. More preferably, it is 75-170 degreeC, More preferably, it is 80-160 degreeC. The heat treatment method is not limited, but among the polyester films, the polylactic acid film has a large heat shrinkage stress at a temperature higher than the glass transition point, and the film running direction in the tenter due to the temperature difference between the stretching temperature and the heat treatment temperature. Since the bowing phenomenon exhibiting a concave curve toward the surface is often a problem, it is preferable to perform a step heat treatment in which the temperature of the heat treatment zone is changed stepwise. (For example, when the heat treatment zone is divided into three zones, zone 1: 100 ° C., zone 2: 120 ° C., zone 3: 160 ° C.) After proper stretching, relaxation heat treatment is performed under such conditions, A small film with good flatness can be obtained.

Moreover, when the vapor deposition layer which gave the vapor deposition layer which consists of a metal or an inorganic oxide to the A1 layer of the film of this invention produced with the said method and was made into the vapor deposition processed vapor film, water vapor permeability is 2. It is preferably 0 g / m ² / day or less. When the water vapor permeability exceeds 2.0 g / m ² / day, the water vapor barrier property is inferior, and when the film is processed into a package using the film as a packaging material, the freshness retaining property of the contents may be inferior. The water vapor permeability of the vapor-deposited film is more preferably 1.0 g / m ² / day or less, more preferably 0.5 g / m ² / day or less, most preferably for applications requiring better water vapor barrier properties. Preferably it is 0.1 g / m ² / day or less. In addition, water vapor | steam barrier property is so preferable that it is preferable, and especially a minimum is not provided, but it is guessed that about 0.01 g / m < ² > / day is a minimum which can be implement | achieved. The water vapor transmission rate is the center line average surface roughness of the layer on which the vapor deposition layer is formed, the type of metal or inorganic oxide of the vapor deposition layer, the thickness of the vapor deposition layer, defects in the vapor deposition layer (pinholes, scratches, etc. ) The amount can be controlled by the adhesion of the deposited film and the deposited film.

Moreover, it is preferable that oxygen permeability is 2.0 cc / m < ² > / day / atm or less. When the oxygen permeability of the vapor deposition film exceeds 2.0 cc / m ² / day / atm, the oxygen barrier property is inferior, and when the vapor deposition film is processed into a package using the packaging material, the freshness of the contents is maintained. May be inferior. Oxygen permeability of the deposited film is to use a more excellent oxygen barrier properties is desired, more preferably not more than ^{1.0cc / m 2 / day / atm} , more preferably 0.5cc ^/ m 2 ^/ day ^/ It is atm or less, and most preferably 0.1 cc / m ² / day / atm or less. In addition, although oxygen barrier property is so preferable that it is favorable, especially a minimum is not provided, but about 0.01 cc / m < ² > / day / atm is guessed as a feasible minimum. The oxygen permeability of the deposited film is determined by the average surface roughness of the layer on which the deposited layer is formed, the thickness of the gas barrier resin layer, the type of metal or inorganic oxide in the deposited layer, the thickness of the deposited layer, the thickness of the deposited layer, It can be controlled by the amount of defects (pinholes, scratches, etc.).

  In addition, when the film of this invention has a vapor deposition layer, the vapor deposition layer, A1 layer, and B layer were laminated | stacked in this order, or the vapor deposition layer, A1 layer, B layer, and A2 layer were laminated | stacked in this order. It is preferable that it is an aspect.

  In the polylactic acid oriented film of the present invention, it is important that the noise level value measured by the method described later is 85 dB or less. By setting the noise level value of the polylactic acid-based oriented film to 85 dB or less, it has excellent silence, and can be suitably used for snack packaging applications.

  The polylactic acid oriented film of the present invention can be produced using the above method.

[Methods for measuring physical properties and methods for evaluating effects]
The physical property measuring method and the effect evaluating method in the present invention are as follows.

1. The thickness of each layer The sample was cut out from the center part of the TD direction of a film. Using an ultramicrotome, an ultrathin slice was taken at −100 ° C. by using an ultramicrotome by the resin embedding method using an epoxy resin so that the MD direction-thickness direction cross section of the sample piece was the observation surface. The thin film section of the film cross section was photographed with a scanning electron microscope at a magnification of 1000 times (the magnification can be adjusted as appropriate), and the thickness of each layer was measured. The observation location was changed and measurements were taken at 10 locations, and the average of the obtained values was defined as the thickness (μm) of each layer.

2. Film thickness Using a dial gauge thickness gauge (JIS B7503 (1997), UPAIGHT DIAL GAUGE made by PEACOCK (0.001 × 2 mm), No. 25, measuring element 5 mmφ flat type) at intervals of 10 cm in the MD direction and the TD direction. Ten points were measured, and the average value was defined as the film thickness (μm) of the film.

3. Water vapor permeability Under conditions of a temperature of 38 ° C. and a humidity of 90% RH, using a water vapor permeability measuring device (model name, “Permatran” (registered trademark) W3 / 31) manufactured by MOCON, USA It measured based on B method (infrared sensor method) as described in JIS K7129 (2008). The measurement was performed by applying a water vapor flow to the film and detecting on the opposite side, and the measurement was performed four times. The average value was defined as the water vapor transmission rate (g / m ² / day) of the film.

4). Oxygen permeability Under the conditions of a temperature of 23 ° C. and a humidity of 0% RH, an oxygen permeability measuring device (model name, “Oxytran” (registered trademark) (“OXTRAN” 2/20)) manufactured by MOCON, USA. It was measured based on the electrolytic sensor method described in JIS K7126-2 (2006). Further, the measurement was performed by applying an oxygen stream to the film and detecting on the opposite side, and the measurement was performed four times. The average value was defined as the oxygen permeability (cc / m ² / day / atm) of the film.

5. Heat seal strength measurement The heat seal strength of the film was measured using a heat seal machine (TP-701S HEAT SEAL TESTER, TESTER SANGYO CO, LTD) with a teflon (2.1 kgf / cm ² ) at a residence time of 1 second. It was performed with a heated flat top seal fixture coated with a registered trademark and a non-heated bottom seal fixture made of rubber and glass cloth. The film was heat-sealed on the A2 layer side within a predetermined sealing temperature range (for example, increments of 10 ° C. in the range of 90 to 160 ° C.), and the respective sealing strengths were measured with a tensile tester manufactured by Daiei Kagaku Seisakusho. . Cut the heat-sealed sample into a 25 mm wide strip, attach the two unsealed ends to the upper and lower clamps of the Instron machine, and the sealed ends against the two unsealed ends Support at an angle of 90 ° and perform a 90 ° T-peel test. The lowest temperature at which a seal strength of 100 g / 25 mm or more could be achieved was defined as the heat seal start temperature, and the heat sealability was judged according to the following criteria. ○ The above is a practically usable range.
A: Heat seal start temperature is 95 ° C. or higher and lower than 115 ° C. ○: Heat seal start temperature is 115 ° C. or higher and lower than 155 ° C. Δ: Seal strength of 100 g / 25 mm or higher cannot be achieved at any seal temperature.

6). Measurement of adhesion strength of deposited film The deposited film obtained by forming a deposited layer on the film was aligned in the longitudinal direction of the unstretched polypropylene film (CPP), and dry laminated under the following conditions.
・ CPP: “Torayfan” NO # 60 ZK93KM manufactured by Toray Film Processing Co., Ltd.
・ Adhesive: Toyo Morton Co., Ltd. AD503 / cat10
-Blending amount: AD503 / cat10 / ethyl acetate = 20/1/20% by mass
-Application | coating: The adhesive agent was apply | coated to the corona treatment surface side of CPP using the metabar # 12.
Drying: 80 ° C., 45 seconds Lamination: After drying, the coated surface on the CPP was laminated on the deposited layer of the film.
Curing: 40 ° C., 48 hours A test piece having a width of 15 mm was taken out from the obtained sample, and a peel test was performed under the following conditions. In the peeling force curve, the upper limit value and the lower limit value after the start of peeling were read and used as the deposited film adhesion strength of the film.
・ Peel tester: Tensile Seiki Seisakusho tensile tester ・ Peel angle: 180 °
・ Peeling speed: 200 mm / min ・ Chart speed: 20 mm / min ・ Peeling direction: MD direction ・ Sample width: 15 mm
Three test pieces were collected from the same sample, and the same measurement was performed three times. The average value of the obtained values was defined as the deposited film adhesive strength (g / 15 mm).

7. Tensile elongation, tensile modulus measurement Tensile elongation (%)
Stress-strain measurement at 23 ° C. was performed using TENSILON UCT-100 manufactured by Orientec Corp. equipped with a thermostatic bath, and the elongation in the MD direction and TD direction at 23 ° C. was measured.

  Specifically, a sample was cut into a strip shape having a length of 150 mm and a width of 10 mm in the MD direction and the TD direction, and the initial tensile chuck distance was 50 mm and the tensile speed was 200 mm / min in a thermostatic chamber adjusted to 23 ° C. The measurement was performed according to the method defined in JIS K-7127 (1999), and the average elongation (%) of 10 measurements was determined in the MD direction and the TD direction.

Tensile modulus (GPa)
Using the method described above, the stress-strain measurement at 23 ° C. is performed, and using the first linear portion of the stress-strain curve, the stress difference between the two points on the straight line is the same as the strain difference between the two points. The tensile modulus was calculated. The measurement was performed 10 times in total, and the average value was adopted. This was calculated for each of the MD direction and the TD direction.

8). Heat shrinkage rate The film of the present invention was cut into a rectangle having a length of 200 mm and a width of 10 mm in the MD direction and the TD direction as a sample. Marks were drawn on the sample at intervals of 150 mm, a 3 g weight was suspended and placed in a hot air oven heated to 120 ° C. for 15 minutes and subjected to heat treatment. The distance between the marked lines was measured after the heat treatment, the thermal shrinkage rate was calculated from the change in the distance between the marked lines before and after heating, and used as an index of dimensional stability. The same measurement was performed five times for each direction of each sample, and the average value of the obtained values was calculated and used as the thermal shrinkage rate (%) in the MD direction and TD direction of the sample.

9. Heat of fusion ΔH (J / g)
Based on JIS K7121 (1999), a differential scanning calorimeter “Robot DSC-RDC220” manufactured by Seiko Instruments Inc. was used, and a disk session “SSC / 5200” was used for data analysis. In a calorific curve obtained when 5 mg of the desired resin composition is sealed in a sample pan, set in the apparatus, and heated from 25 ° C. to 250 ° C. at a rate of 20 ° C./min in a nitrogen atmosphere, the baseline is The area of the exothermic peak accompanying the melting of the crystal was obtained as a straight line and was taken as ΔH (J / g).

10. Film silence evaluation (measurement of noise level)
The quietness of the film is a set of omnidirectional microphones (1/2 inch electric microphone (UC-53A), preamplifier (NH-22)), FFT analyzer (SA-78), and Catec Co., Ltd. Using the waveform analysis software (CAT-WAVE) and gel bot tester (specified in ASTM F-392), the measurement was carried out and evaluated by the following method.

Cut out the A4 sample so that the MD direction is the long side of the film, and attach both ends of the short side of the A4 cut sample to the sample set part of the gel bot tester with double-sided tape, and repeat the fatigue test for 30 seconds at room temperature. went. The sound emitted at that time was picked up by an omnidirectional microphone (UC-53A and NH-22) set at a position 5 cm away from the center of the film and SA-78 to obtain waveform data. The waveform data was subjected to FFT conversion by CAT-WAVE, and the noise level (dB) was collected. The same measurement was performed three times, and the average value of the obtained values was defined as the film noise level (dB), which was used as an index for evaluating the quietness. The measurement was performed in a soundproof room in order to shut down the sound from the outside, and a sound absorbing material (foamed PE) was attached to the wall surface in the gel bot tester in order to suppress the sound reflection in the gel bot tester. Carried out in a state. The SA-78 measurement conditions and the CAT-WAVE analysis conditions were as follows.
FFT analyzer (SA-78)
・ Calibration setting
Calibration mode LIN
Transfer value (Ach 1 EU = 4.31 × 10 ^-2 , Bch 1 EU = 1.11 × 10 ^-3 )
Reference value Ach 0dB EU = 2.0 × 10 ^-5
Waveform analysis software (CAT-WAVE)
・ Analysis mode → FFT & OCT
・ Trigger setting → Free ・ Analysis frequency → 20000 Hz
・ Number of analysis points → 4096
-Time window function-> Rectangle-Average method-> Frequency [Automatic] 1600 Hz increments 1600 points-Measurement range-> 14 cycles 20.2 seconds (1 cycle approx. 1.44 seconds)
-A characteristics The quietness was judged according to the following criteria. ○ The above is a practically usable range.
(Double-circle): A noise level is less than 85 dB and is very excellent in silence.
◯: The noise level is 85 dB or more and less than 90 dB, and the silence is excellent.
(Triangle | delta): A noise level is 90 dB or more and less than 95 dB, and it is inferior to silence.
X: A noise level is 95 dB or more, and it is very inferior to silence.

11. Quantitative evaluation of deposited film defects Using a differential interference microscope (Leica DMLB HC manufactured by Leica Microsystems), the deposited film defects (pinholes, scratches) of the deposited film were observed and photographed at a magnification of 50 times by the transmission method. did. In addition, in order to ensure the reliability of data, the observation location was changed and the measurement was performed at 12 locations. We also analyzed the data using the image analysis free software (ImageJ) developed by the National Institutes of Health, and quantified the defects in the deposited film. ImageJ analysis conditions were as follows.
・ Discard color information → 8-bit
-Black / white reversal->Yes-Binarization-> Threshold value: 190
These operations were applied to all 12 samples, and the average number of defects (/ mm ² ) was calculated. It is clear that there is a strong correlation between the number of defects, water vapor barrier properties, and oxygen barrier properties. The smaller the number of defects, the better the water vapor barrier properties and oxygen barrier properties. In addition, the ability as a gas barrier film was judged on the following reference | standard. The above is the range that can be practically used as a film having good gas barrier properties.
(Double-circle): The vapor deposition film defect is hardly observed, the number of defects is less than 5, and water vapor | steam barrier property is less than 1.0 g / m < ² > / day.
◯: Although some deposited film defects are observed, the number of defects is 5 or more and less than 15, and the water vapor barrier property is 1.0 or more and less than 2.0 g / m ² / day.
(Triangle | delta): Many vapor deposition film defects are observed, the number of defects is 15 or more and less than 25, and the water vapor | steam barrier property is bad in connection with it, and is 2.0 or more and less than 4.0 g / m < ² > / day.
X: The majority of the deposited film defects are observed, the number of defects is 25 or more, and the water vapor barrier property is very poor accordingly, and is 4.0 g / m ² / day or more.

The raw materials used in the production examples, examples, and comparative examples of the present invention are as follows. In the production examples, examples, and comparative examples, the following abbreviations may be used.
[CPLA]
Crystalline poly-L-lactic acid (“Ingeo” 4032D manufactured by Nature Works; D-form amount = 1.4 mol%, melting point = 168 ° C., Tg = 58 ° C.) dried at 100 ° C. for 4 hours in a rotary vacuum dryer.
[CPLA-MB1]
A cPLA-MB1 chip was prepared by blending 95% by mass of the above cPLA and 5% by mass of “Silton” JC-30 manufactured by Mizusawa Chemical Co., Ltd. and drying at 100 ° C. for 5 hours.
[APLA]
Amorphous poly-L-lactic acid (“Ingeo” 4060D manufactured by Nature Works; D body amount = 12 mol%, Tg = 58 ° C.) dried for 8 hours at 50 ° C. in a rotary vacuum dryer.
[APLA-MB2]
In the aPLA, 95% by mass of the aPLA and 5% by mass of “Silton” JC-30 manufactured by Mizusawa Chemical Co., Ltd. were blended, and the chip dried at 50 ° C. for 5 hours was designated as aPLA-MB2.
[PMMA]
Polymethylmethacrylate (VS-100 manufactured by Arkema) dried for 8 hours at 80 ° C. in a rotary vacuum dryer.
[Flexible resin 1]
62 parts by mass of polyethylene glycol having a number average molecular weight of 8,000, 38 parts by mass of L-lactide and 0.05 parts by mass of tin octylate are mixed and polymerized in a reaction vessel equipped with a stirrer at 160 ° C. for 3 hours in a nitrogen atmosphere. Thus, a PLA-PEG-PLA type block copolymer having a number average molecular weight of 2,500 polylactic acid segments at both ends of a polyethylene glycol having a number average molecular weight of 8,000 and a flexible resin 1 were obtained. In addition, drying was performed for 5 hours at 80 degreeC with the rotary vacuum dryer.
[Flexible resin 2]
Polybutylene adipate terephthalate resin (manufactured by BASF, trade name “Ecoflex” FBX7011). In addition, drying was performed for 5 hours at 65 degreeC with the rotary vacuum dryer.
[Flexible resin 3]
Aliphatic aromatic polyester resin “Matterby” (Novamont, trade name “Matterby” CF51A). In addition, drying was performed for 5 hours at 65 degreeC with the rotary vacuum dryer.
[Flexible resin 4]
Polybutylene succinate resin (trade name “GSPla” AZ91T, manufactured by Mitsubishi Chemical Corporation). In addition, drying was performed for 5 hours at 65 degreeC with the rotary vacuum dryer.
[Flexible resin 5]
Polybutylene succinate / adipate resin (made by Showa Polymer Co., Ltd., trade name “Bionore” # 3001). In addition, drying was performed for 5 hours at 65 degreeC with the rotary vacuum dryer.
[Flexible resin 6]
Poly (3-hydroxybutyrate / 3-hydroxyvalerate) (trade name “PHBV” manufactured by Kaneka Corporation). In addition, drying was performed for 5 hours at 65 degreeC with the rotary vacuum dryer.
[Flexible resin 7]
Diglycerin tetraacetate (abbreviation: DGTA) (trade name “Riquemar” PL710, manufactured by Riken Vinyl Co., Ltd.). Low molecular weight type plasticizer. In addition, drying was performed for 5 hours at 65 degreeC with the rotary vacuum dryer.

The present invention will be described based on examples. In addition, in order to obtain a desired thickness configuration, the polymer extrusion amount of each extruder was adjusted to a predetermined value unless otherwise specified.
Example 1
As shown in Table 1-1, a blend raw material in which 97% by mass of aPLA and 3% by mass of aPLA-MB2 are mixed in advance as a resin composition of the A layer is supplied to a single screw extruder (A) at 220 ° C. The polymer was filtered through a filter obtained by sintering and compressing stainless steel fibers having an average opening of 65 μm and supplied to a multi-manifold die of a two-kind / three-layer laminated type. In addition, as a resin composition for the B layer, a mixture of 60% by mass of aPLA, 20% by mass of cPLA, and 20% by mass of flexible resin 1 was subjected to a twin screw extruder with a vacuum vent with a cylinder diameter of 220 ° C. and a screw diameter of 44 mm. Then, the mixture was melted and kneaded while degassing the vacuum vent part, homogenized, and pelletized. This B-layer resin composition was supplied to a single screw extruder (B), extruded at 220 ° C., and stainless steel fibers having an average opening of 65 μm were sintered and compressed in a flow path different from that of the extruder (A). After the polymer is filtered through a filter, the polymer is supplied to the multi-manifold die and joined in the multi-manifold die so as to be laminated in the order of extruder (A) / extruder (B) / extruder (A). Co-extruded into a sheet form from the die. At this time, the extruded sheet was cast on a mirror metal drum having a temperature of 30 ° C. and cooled and solidified into a sheet.

  The obtained unstretched sheet was stretched 3 times in the longitudinal direction at 75 ° C. with a roll stretching machine, and immediately cooled to room temperature. Next, the obtained uniaxially stretched film was introduced into a tenter and stretched 3 times in the transverse direction at 75 ° C. while holding both edges with clips. Next, the heat treatment zone was divided into two sections, and the first section was heat-treated at 120 ° C., and the second section was subsequently heat-treated at 160 ° C. while giving 5% relaxation in the lateral direction, cooled and wound up.

The obtained biaxially stretched film was 20 μm, and the thickness constitution was A1 layer / B layer / A2 layer = 1.5 / 16 / 2.5. In addition, after aging the biaxially stretched film for 24 hours, the surface of the A1 layer was subjected to corona treatment in a nitrogen atmosphere at a treatment strength of 30 W · min / m ² , and then in a vacuum deposition apparatus equipped with a film running device. Set. After making it the high pressure reduction state of 1.00 * 10 ^<-2 > Pa, it was made to drive | work on the 0 degreeC cooling metal drum. At this time, the aluminum metal was heated and evaporated to form a vapor deposition layer on the A1 layer, and aged for 48 hours to obtain a vapor deposition layer on the A1 layer. The said film was made into the film of this invention. The optical density was confirmed online during vapor deposition, and the vapor deposition thickness was controlled to be 2.5.
The

The characteristic values of the obtained film are as shown in Table 2-1. It has sufficient mechanical properties necessary for use as a film for packaging materials, etc., and it is excellent for various physical properties such as heat sealability, quietness, water vapor barrier property, oxygen barrier property, and deposited film adhesion strength. It was.
(Example 2)
As shown in Table 1-1, a film produced in the same manner as in Example 1 except that the resin used for the B layer was changed to 70% by mass of aPLA, 23% by mass of cPLA, and 7% by mass of the flexible resin 1 Example 2 was adopted. The characteristic values of the obtained film are as shown in Table 2-1, and although the quietness is slightly inferior to the film of Example 1 because of the low content of the flexible resin, It was a sufficiently usable level. Moreover, all were excellent about various physical properties, such as heat seal property, water vapor | steam barrier property, oxygen barrier property, and vapor deposition film adhesive strength (Example 3).
As shown in Table 1-1, a film manufactured in the same manner as in Example 1 except that the resin used for the B layer was changed to 49% by mass of aPLA, 16% by mass of cPLA, and 35% by mass of the flexible resin 1 Example 3 was adopted. The characteristic values of the obtained film are as shown in Table 2-1, and all were excellent in terms of various physical properties such as heat sealability, silence, water vapor barrier property, oxygen barrier property, and deposited film adhesion strength.

Example 4
As shown in Table 1-1, a film manufactured in the same manner as in Example 1 except that the resin used for the B layer was changed to 41% by mass of aPLA, 14% by mass of cPLA, and 45% by mass of the flexible resin 1 Example 4 was adopted. The characteristic values of the obtained film are as shown in Table 2-1, and the mechanical properties were slightly inferior because of the large content of the flexible resin, but the heat sealability, silence, water vapor barrier property And various physical properties such as oxygen barrier properties and deposited film adhesion strength were all excellent (Examples 5 to 9).
As shown in Table 1-1, except that the resin used for the B layer was changed to 20% by mass of aPLA, 60% by mass of cPLA, and 20% by mass of the flexible resin 2 (or 3, 4, 5, 6). Films produced in the same manner as Example 1 were designated as Examples 5-9. The characteristic values of the obtained film are as shown in Table 2-1, and although the quietness was slightly inferior to that of the film of Example 1, it was at a level that could be sufficiently used as a silenced film. All of the various physical properties such as heat sealability, water vapor barrier property, oxygen barrier property, and adhesion strength of the deposited film were excellent.

(Example 10)
As shown in Table 1-2, Example 1 was used except that the resin used for the B layer was changed to 60% by mass of aPLA, 20% by mass of cPLA, 10% by mass of flexible resin 1, and 10% by mass of flexible resin 3. A film produced in the same manner as in Example 10 was designated as Example 10. The characteristic values of the obtained film are as shown in Table 2-2, and all were excellent with respect to various physical properties such as heat sealability, silence, water vapor barrier property, oxygen barrier property, and deposited film adhesion strength.

(Example 11)
As shown in Table 1-2, the resin used for the A layer is changed to a blend raw material in which 57% by mass of aPLA, 3% by mass of aPLA-MB2 and 40% by mass of PMMA are mixed in advance, and the transverse stretching temperature is set to 90 ° C. A film produced in the same manner as in Example 1 except that the change was made was designated as Example 11. The characteristic values of the obtained film are as shown in Table 2-2, and all were excellent with respect to various physical properties such as heat sealability, silence, water vapor barrier property, oxygen barrier property, and deposited film adhesion strength.

(Example 12)
As shown in Table 1-2, the resin used for the A layer is 77.6% by mass of aPLA, 2.4% by mass of aPLA-MB2, 19.4% by mass of cPLA, and 0.6% by mass of cPLA-MB1. A film produced in the same manner as in Example 1 except that the blend raw material was mixed in advance was used as Example 12. The characteristic values of the obtained film are as shown in Table 2-2, and all were excellent with respect to various physical properties such as heat sealability, silence, water vapor barrier property, oxygen barrier property, and deposited film adhesion strength.

(Example 13)
As shown in Table 1-2, the resin used for the A layer is 53.4% by mass of aPLA, 1.6% by mass of aPLA-MB2, 43.7% by mass of cPLA, and 1.3% by mass of cPLA-MB1. A film produced in the same manner as in Example 1 except that the blend raw material was mixed in advance was used as Example 13. The characteristic values of the obtained film are as shown in Table 2-2. Although the quietness is good, the content of cPLA in the surface layer is increased, so that the heat sealability and water vapor barrier are higher than those in Example 1. Properties, oxygen barrier properties, and deposited film adhesion strength were slightly inferior.

(Example 14)
As shown in Table 1-2, a film manufactured in the same manner as in Example 1 except that the thickness configuration was changed to A1 layer / B layer / A2 layer = 3/12/5 was used as Example 14. The characteristic values of the obtained film are as shown in Table 2-2, and although the silence was good, the film had poor flatness. Moreover, compared with Example 1, it became inferior also regarding water vapor | steam barrier property, oxygen barrier property, and vapor deposition film adhesive strength.

(Comparative Example 1)
As shown in Table 1-2, the resin used for the A layer is 43.7% by mass of aPLA, 1.3% by mass of aPLA-MB2, 53.4% by mass of cPLA, and 1.6% by mass of cPLA-MB1. A film produced in the same manner as in Example 1 except that the blend raw material was mixed in advance was used as Comparative Example 1. The characteristic values of the obtained film are as shown in Table 2-2, and although the quietness is good, since the content of cPLA in the surface layer is increased, the heat sealability is inferior compared to Example 1. It was. In addition, when defects in the deposited film were observed with a differential interference microscope, defects (pinholes, scratches) were confirmed, and the water vapor barrier property, oxygen barrier property, and deposited film adhesion strength were poor, and the practicality was poor. It was.
(Comparative Example 2)
As shown in Table 1-2, a film produced in the same manner as in Example 1 except that the resin used for the A layer was changed to a blend raw material in which 97% by mass of cPLA and 3% by mass of cPLA-MB1 were mixed in advance. It was set as Comparative Example 2. The characteristic values of the obtained film are as shown in Table 2-2. As in Comparative Example 1, the heat sealability is inferior, and many defects (pinholes, scratches) were confirmed in the deposited film. The water vapor barrier property, the oxygen barrier property, and the adhesion strength of the deposited film were poor and the practicality was poor.
(Comparative Example 3)
As shown in Table 1-2, a film manufactured in the same manner as in Example 1 except that the resin used for the B layer was changed to a blend raw material in which 20% by mass of aPLA and 80% by mass of cPLA were mixed in advance was a comparative example. It was set to 3. The characteristic values of the obtained film are as shown in Table 2-2. Since the content of cPLA in the surface layer was increased, the heat sealing property, water vapor barrier property, oxygen barrier property, vapor deposition film as compared with Example 1 were obtained. Although properties such as adhesive strength are excellent, an unpleasant sound peculiar to a polylactic acid film is increased when touched or folded, and the quietness is greatly inferior.

(Comparative Example 4)
As shown in Table 1-2, the resin used for the A layer and the B layer is 57.75% by mass of aPLA, 2.25% by mass of aPLA-MB2, 19.25% by mass of cPLA, and 0.75 of cPLA-MB1. A film manufactured in the same manner as in Example 1 was used as Comparative Example 4 except that the film was changed to 20% by mass and the resin 1 was changed to 20% by mass to form a single film. The characteristic values of the obtained film are as shown in Table 2-2, and although it was excellent in silence, it was inferior in heat sealability. Also, the reason why the layer A, which is the vapor deposition receiving layer, contained a flexible resin, or when the vapor deposition film defects of the vapor deposition film were observed with a differential interference microscope, a large number of defects (pinholes, scratches) were confirmed, and the water vapor barrier property Further, the oxygen barrier property and the adhesion strength of the deposited film were deteriorated and the practicality was inferior.

(Comparative Example 5)
As shown in Table 1-2, the resin used for the A layer and the B layer was changed to 77% by mass of cPLA, 3% by mass of cPLA-MB1, and 20% by mass of the flexible resin 7 to obtain a film having a single film configuration. The film produced in the same manner as in Example 1 was referred to as Comparative Example 5. The characteristic values of the obtained film are as shown in Table 2-2, and although it was excellent in silence, it was inferior in heat sealability. In addition, the low-molecular-weight type plasticizer contained in layer A, which is the vapor-depositing receiving layer, bleeded out, and when the film defects in the vapor-deposited film were observed with a differential interference microscope, many defects (pinholes, scratches) The water vapor barrier property, the oxygen barrier property, and the adhesion strength of the deposited film deteriorated, and the practicality was inferior.

(Comparative Example 6)
As shown in Table 1-2, a film produced in the same manner as in Example 1 was used as Comparative Example 6 except that the resin used for the B layer was changed to 80% by mass of cPLA and 20% by mass of the flexible resin 7. The characteristic values of the obtained film are as shown in Table 2-2. Although the plasticizer was contained in the B layer, it was a low molecular weight type plasticizer, so that bleed out was confirmed. In addition, when the defects of the deposited film were observed with a differential interference microscope, a large number of defects (pinholes, scratches) were confirmed, and the water vapor barrier property, oxygen barrier property, and deposited film adhesion strength deteriorated, making it practical. It was inferior.

  TECHNICAL FIELD The present invention relates to a polylactic acid oriented film having excellent silence and gas barrier properties that could not be achieved by the prior art, and snack packaging requiring a very high level of gas barrier properties. It can be preferably used for applications.

Claims (4)

Mainly made of polylactic acid resin,
The noise level is 85 dB or less,
A polylactic acid oriented film having a water vapor permeability of 2.0 g / m ² / day or less.   The polylactic acid oriented film according to claim 1, wherein a vapor deposition layer, an A1 layer mainly composed of amorphous polylactic acid resin, and a B layer mainly composed of polylactic acid resin are laminated in this order. .   A block copolymer having a polyether-based segment and a polylactic acid-based segment, a block copolymer having a polyester-based segment and a polylactic acid-based segment, and an aliphatic polyester-based resin (100% by mass of all the components of layer B) 3. The composition contains 4 to 40% by mass of at least one resin selected from the group consisting of aliphatic aromatic polyester resins (hereinafter, excluding polylactic acid resins) and aliphatic aromatic polyester resins. The polylactic acid-based oriented film described in 1. A vapor deposition layer, an A1 layer mainly composed of an amorphous polylactic acid resin, a B layer mainly composed of a polylactic acid resin, and an A2 layer mainly composed of an amorphous polylactic acid resin are laminated in this order. And
The thickness of the A1 layer is 2 μm or less, the thickness of the A2 layer is 2 μm or more,
The polylactic acid oriented film according to any one of claims 1 to 3, wherein (total thickness of A1 layer and A2 layer) / (total thickness of B layer) ≤ 0.5.