Laminated films and packaging bags

Abstract

To provide an aluminum-free laminated film having excellent gas barrier properties and tear strength.SOLUTION: A laminated film according to one embodiment of the present invention includes a substrate layer, and a sealant layer, which serves as one of its outermost surfaces. The substrate layer contains a liquid crystal polymer and a modified polyethylene terephthalate.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a laminated film and a packaging bag. [Background technology]

[0002] Conventionally, packaging bags made of a laminated film in which a sealant layer is laminated on the inner surface of a base layer made of film, paper, etc. have been widely used as packaging bags for containing contents such as food, medicine, etc. The laminated film used in such packaging bags generally has gas barrier properties that block the entry of gases that deteriorate the contents, such as water vapor and oxygen, in order to prevent deterioration and spoilage of the contents and to maintain their functions and properties.

[0003] For example, Patent Document 1 discloses a packaging bag made by laminating a base layer / first adhesive layer / gas barrier layer / second adhesive layer / sealant layer in that order to form a sealed portion by sealing a laminated film with the sealant layer as the inner surface. It also discloses that the gas barrier layer is a polyester film vapor-deposited with aluminum or an inorganic oxide, which provides excellent gas barrier properties and enables the quality of the fragrance to be maintained for a long time. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-5013 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in conventional laminate films, the gas barrier layer is often an aluminum-deposited polyester film or aluminum foil, and such aluminum-containing laminate films generate a large amount of CO2 during the manufacturing and disposal processes, and are difficult to separate and recover when disposed of. To address this problem, it has been considered to use a liquid crystal polymer, which has excellent gas barrier properties, as the gas barrier layer, but liquid crystal polymers have the disadvantage of lacking tear strength when processed into films.

[0006] In view of the above, one aspect of the present invention aims to provide an aluminum-free laminate film having excellent gas barrier properties and tear strength. [Means for solving the problem]

[0007] A laminated film according to one aspect of the present invention has a base layer and a sealant layer that forms one of the outermost surfaces, and the base layer contains a liquid crystal polymer and modified polyethylene terephthalate. [Effects of the Invention]

[0008] According to one aspect of the present invention, an aluminum-free laminate film having excellent gas barrier properties and tear strength can be provided. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic diagram showing a cross section of a laminated film according to one embodiment. [Figure 2] 1 is a schematic diagram of a packaging bag according to one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In this specification, unless otherwise specified, the symbol "to" indicating a numerical range means that the numerical values ​​before and after it are included as the lower and upper limits. FIG. 1 is a schematic diagram showing a cross section of a laminated film 1 according to one embodiment. The laminated film 1 of this embodiment has a base layer 2 and a sealant layer 3. The sealant layer 3 forms one outermost surface of the laminated film 1. Here, the sealant layer 3 is a layer used for heat sealing, and when the laminated film 1 is used as a packaging material, it is the layer disposed as the innermost layer that comes into contact with the contents. The base layer 2 and the sealant layer 3 may be bonded via an adhesive layer or an anchor agent layer, but are preferably bonded directly.

[0011] The base layer 2 contains a liquid crystal polymer (A) and a modified polyethylene terephthalate (B), or may consist of the liquid crystal polymer (A) and the modified polyethylene terephthalate (B).

[0012] The liquid crystal polymer (A) used in the base layer 2 of this embodiment is preferably one that does not contain inorganic substances such as glass, fillers, etc. Examples of the liquid crystal polymer (A) include VECTORA (registered trademark) and ZENITE (registered trademark) manufactured by Celanese, and UENO LCP (registered trademark) manufactured by Ueno Pharmaceutical Co., Ltd.

[0013] When the laminate film 1 is used as a packaging material, the substrate layer 2, which is located outside the sealant layer 3 that contacts the contents, contains a liquid crystal polymer (A) and a modified polyethylene terephthalate (B), and thus can block the intrusion of gas from the outside, allowing the laminate film 1 of this embodiment to exhibit excellent gas barrier properties. In this specification, gas barrier properties refer to the property of blocking gas, and include water vapor barrier properties that block water vapor and oxygen barrier properties that block oxygen. Furthermore, since the substrate layer 2 contains the liquid crystal polymer (A) and the modified polyethylene terephthalate (B), the substrate layer 2 and the laminate film 1 having the substrate layer 2 have excellent tear strength. Because the substrate layer 2 has excellent tear strength, the laminate film 1 has good processability.

[0014] The laminate film 1 of this embodiment is aluminum-free (does not contain aluminum), which reduces the amount of CO2 generated during the manufacturing and disposal processes. Furthermore, when discarded, the laminate film 1 can be disposed of as plastic waste, allowing for easy separation and recovery. Furthermore, the liquid crystal polymer (A) and modified polyethylene terephthalate (B) that constitute the base layer 2 have good affinity and can be mixed uniformly, so they can be mixed without the need for, for example, adding a reactive compatibilizer. Therefore, the laminate film 1 of this embodiment has excellent recyclability. Furthermore, because the laminate film 1 of this embodiment is aluminum-free, it can be used in production lines that use metal detectors to detect metallic foreign objects.

[0015] The content of the liquid crystal polymer (A) relative to the base layer 2 is preferably 78 parts by mass to 99 parts by mass, and more preferably 80 parts by mass to 90 parts by mass. By setting the content of the liquid crystal polymer (A) to 78 parts by mass to 99 parts by mass, the laminate film 1 of the present embodiment can exhibit better gas barrier properties and tear strength.

[0016] The modified polyethylene terephthalate (B) used in the base layer 2 of this embodiment is a linear polyester resin obtained by condensation polymerization of a dicarboxylic acid component and a diol component, and is a copolymer in which the dicarboxylic acid component is primarily composed of terephthalic acid and further contains a dicarboxylic acid other than terephthalic acid, and the diol component is primarily composed of ethylene glycol, or a copolymer in which the dicarboxylic acid component is primarily composed of terephthalic acid, the diol component is primarily composed of ethylene glycol, and further contains a diol other than ethylene glycol. In this specification, the term "main component" refers to the component with the highest content. Note that the modified polyethylene terephthalate (B) is non-liquid crystal and is not included in the liquid crystal polymer (A).

[0017] Examples of the dicarboxylic acid component include terephthalic acid, aromatic dicarboxylic acids such as isophthalic acid, naphthalene-1,4-dicarboxylic acid, and naphthalene-2,6-dicarboxylic acid, and aliphatic dicarboxylic acids such as adipic acid and sebacic acid.

[0018] Examples of the diol component include, in addition to ethylene glycol, linear diols such as 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexamethylenediol; cyclic diols such as cyclopentane dimethanol and cyclohexane dimethanol; and branched diols such as neopentyl glycol, 2,2-diethyl-1,3-propanediol, 2,2-dipropyl-1,3-propanediol, 2-propyl-2-methyl-1,3-propanediol, 2-propyl-2-ethyl-1,3-propanediol, 2-isopropyl-2-methyl-1,3-propanediol, 2-isopropyl-2-ethyl-1,3-propanediol, 2-butyl-2-methyl-1,3-propanediol, and 2-butyl-2-ethyl-1,3-propanediol. A branched diol has one or more alkyl groups as side chains branching from the main chain, whereas a linear diol has only a main chain containing two hydroxyl groups.

[0019] The modified polyethylene terephthalate (B) preferably contains at least one of isophthalic acid-modified polyethylene terephthalate modified with isophthalic acid and polyethylene terephthalate modified with a diol having two alkyl groups (hereinafter also referred to as "dialkyl-substituted diol-modified polyethylene terephthalate"). This configuration allows the laminate film 1 of the present embodiment to exhibit excellent gas barrier properties and tear strength.

[0020] Isophthalic acid-modified polyethylene terephthalate is a copolymer of a linear polyester resin obtained by condensation polymerization of a dicarboxylic acid component and a diol component, in which the dicarboxylic acid component is primarily composed of terephthalic acid and further contains isophthalic acid, and the diol component is primarily composed of ethylene glycol.

[0021] When the modified polyethylene terephthalate (B) contains isophthalic acid-modified polyethylene terephthalate, the copolymerization ratio of the isophthalic acid component in the dicarboxylic acid component constituting the isophthalic acid-modified polyethylene terephthalate is preferably 3 mol% to 30 mol%, and more preferably 5 mol% to 25 mol%. Here, the copolymerization ratio of the isophthalic acid component in the dicarboxylic acid component refers to the proportion (mol percentage) of the isophthalic acid component in the dicarboxylic acid component. When the copolymerization ratio of the isophthalic acid component in the dicarboxylic acid component is 3 mol% or more, the laminate film 1 of this embodiment can exhibit better gas barrier properties and tear strength, and can prevent necking during film formation of the base layer 2, thereby achieving good processability. Furthermore, by having a copolymerization ratio of the isophthalic acid component in the dicarboxylic acid component of 30 mol% or less, it is possible to provide a laminated film 1 having heat resistance capable of withstanding the heat when heat-sealing laminated films 1 to each other or laminated film 1 to other films, or heat resistance capable of withstanding the heat of the contents when hot contents are filled into a packaging bag or the like formed from laminated film 1.

[0022] The intrinsic viscosity (IV) of the isophthalic acid-modified polyethylene terephthalate is preferably 0.60 dL / g to 0.85 dL / g. Here, the intrinsic viscosity is a value measured in accordance with JIS K 7367-5 in a mixed solvent of phenol / 1,1,2,2-tetrachloroethane (1 / 1 by mass ratio) at 30°C. When the intrinsic viscosity is 0.60 dL / g or more, the laminate film 1 of this embodiment can exhibit better gas barrier properties. Furthermore, when the intrinsic viscosity is 0.85 dL / g or less, the base layer 2 can be easily extruded, and the processability of the laminate film 1 can be improved.

[0023] When the modified polyethylene terephthalate (B) is isophthalic acid-modified polyethylene terephthalate, it is preferable that the content of the liquid crystal polymer (A) relative to the base layer 2 is 78 parts by mass to 99 parts by mass, and the content of the isophthalic acid-modified polyethylene terephthalate relative to the base layer 2 is 1 part by mass to 22 parts by mass. When the contents of the liquid crystal polymer (A) and the isophthalic acid-modified polyethylene terephthalate are within the above ranges, the laminate film 1 of the present embodiment can exhibit better gas barrier properties and tear strength.

[0024] Dialkyl-substituted diol-modified polyethylene terephthalate is a copolymer of a linear polyester resin obtained by condensation polymerization of a dicarboxylic acid component and a diol component, in which the dicarboxylic acid component is primarily composed of terephthalic acid, the diol component is primarily composed of ethylene glycol, and the copolymer further contains a diol having two alkyl groups.

[0025] The diol having two alkyl groups has two alkyl groups on the side chain of the branched diol. By using a diol having two alkyl groups as part of the diol component to modify polyethylene terephthalate, the crystallinity of the polyethylene terephthalate can be reduced, making it amorphous or low-crystalline. This can improve the tear strength of the laminated film 1.

[0026] Diols with two alkyl groups have the general formula HO(CH2) n In a linear diol having n carbon atoms, represented by OH, two of the total 2n hydrogen atoms are substituted with alkyl groups. The number of carbon atoms in the main chain, n, is, for example, within the range of 1 to 6. The positions a and b of the carbon atoms substituted with alkyl groups can each be independently selected within the range of 1 to n.

[0027] If the dialkyl substitution position a or b of the diol is equal to 1 or n, the hydroxyl group becomes a secondary or tertiary alcohol, which may make it difficult to proceed with the condensation reaction with the carboxylic acid component during the synthesis of the dialkyl-substituted diol-modified polyethylene terephthalate. For this reason, it is preferable that the alkyl group substitution positions a and b are greater than 1 and smaller than n.

[0028] When the positions a and b of the dialkyl substitution are equal, the general formula of a diol with two alkyl groups is HO(CH2) a-1 C(R1)(R2)(CH2) n-a It is represented by OH. R1 and R2 are each an alkyl group having, for example, 1 to 6 carbon atoms. Examples of the alkyl group include a methyl group having 1 carbon atom, an ethyl group having 2 carbon atoms, a propyl group or an isopropyl group having 3 carbon atoms, a butyl group or an isobutyl group having 4 carbon atoms, and a pentyl group or an isopentyl group having 5 carbon atoms.

[0029] The carbon number n of the main chain of a diol having two alkyl groups is more preferably 3 to 4, and the carbon numbers of the alkyl groups R1 and R2 are more preferably 1 to 4. For example, in the case of neopentyl glycol or 2-butyl-2-ethyl-1,3-propanediol, n=3 and a=b=2. In neopentyl glycol, i.e., 2,2-dimethyl-1,3-propanediol, R1 and R2 are methyl groups. In 2-butyl-2-ethyl-1,3-propanediol, R1 and R2 are butyl and ethyl groups, respectively.

[0030] When the modified polyethylene terephthalate (B) contains a dialkyl-substituted diol-modified polyethylene terephthalate, the copolymerization ratio of the diol having two alkyl groups in the diol component constituting the dialkyl-substituted diol-modified polyethylene terephthalate is preferably 10 mol% to 40 mol%, and more preferably 15 mol% to 30 mol%. Here, the copolymerization ratio of the diol component having two alkyl groups in the diol component refers to the molar percentage of the diol component having two alkyl groups in the diol component. By having a copolymerization ratio of the diol component having two alkyl groups of 10 mol% or more, the laminate film 1 of this embodiment can exhibit better gas barrier properties and tear strength, and can prevent necking during film formation of the base layer 2, thereby achieving good processability. Furthermore, by having a copolymerization ratio of the diol component having two alkyl groups of 40 mol% or less, it is possible to provide a laminate film 1 having heat resistance that can withstand the heat generated when heat-sealing laminate films 1 to each other or between laminate film 1 and another film, or when hot contents are filled into a container formed from laminate film 1.

[0031] The dialkyl-substituted diol-modified polyethylene terephthalate is preferably neopentyl glycol-modified polyethylene terephthalate modified with neopentyl glycol. Neopentyl glycol-modified polyethylene terephthalate is a copolymer in which the dicarboxylic acid component is primarily terephthalic acid, the diol component is primarily ethylene glycol, and the copolymer further contains neopentyl glycol. Specific examples include Velpet (registered trademark). When the dialkyl-substituted diol-modified polyethylene terephthalate is neopentyl glycol-modified polyethylene terephthalate, the laminate film 1 of this embodiment can exhibit better gas barrier properties and tear strength.

[0032] The intrinsic viscosity (IV) of the neopentyl glycol-modified polyethylene terephthalate is preferably 0.70 dL / g to 0.90 dL / g. Here, the intrinsic viscosity is a value measured in accordance with JIS K 7367-5 in a mixed solvent of phenol / 1,1,2,2-tetrachloroethane (1 / 1 by mass ratio) at 30°C. When the intrinsic viscosity is 0.70 dL / g or more, the laminate film 1 of this embodiment can exhibit better gas barrier properties. Furthermore, when the intrinsic viscosity is 0.90 dL / g or less, the base layer 2 can be easily extruded, and the processability of the laminate film 1 can be improved.

[0033] When the modified polyethylene terephthalate (B) is neopentyl glycol-modified polyethylene terephthalate, it is preferable that the content of the liquid crystal polymer (A) relative to the base layer 2 is 83 to 99 parts by mass, and the content of the neopentyl glycol-modified polyethylene terephthalate relative to the base layer 2 is 1 to 17 parts by mass. When the contents of the liquid crystal polymer (A) and the neopentyl glycol-modified polyethylene terephthalate are within the above ranges, the laminate film 1 of the present embodiment can exhibit better gas barrier properties and tear strength.

[0034] The sealant layer 3 of the laminate film 1 is preferably a resin film having excellent heat resistance, mechanical properties, and printability. Specifically, the sealant layer 3 preferably contains one or more of a polyethylene resin, a polypropylene resin, a polyester resin, and a cyclic olefin resin. This allows two laminate films 1 to be placed opposite each other and the sealant layers 3 to be thermally bonded to each other.

[0035] The polyester-based resin is preferably isophthalic acid-modified polyethylene terephthalate modified with isophthalic acid. The isophthalic acid-modified polyethylene terephthalate contained in the sealant layer 3 may be the same as the isophthalic acid-modified polyethylene terephthalate contained in the base layer 2 described above. When the polyester-based resin is isophthalic acid-modified polyethylene terephthalate, the laminate film 1 of this embodiment can exhibit even better gas barrier properties. Furthermore, when the sealant layer 3 contains isophthalic acid-modified polyethylene terephthalate, the adhesion between the sealant layer 3 and the base layer 2 containing the modified polyethylene terephthalate (B) can be improved.

[0036] The sealant layer 3 may contain additives as components other than the resin. The additives are not particularly limited, but examples thereof include antioxidants, lubricants, antiblocking agents, stabilizers, ultraviolet absorbers, flame retardants, antistatic agents, and colorants.

[0037] The laminated film 1 may have another layer provided on the opposite side of the base layer 2 from the sealant layer 3, and the other layer preferably contains a resin other than a liquid crystal polymer. The other layer may include, for example, an intermediate layer, an adhesive layer, an anchoring agent layer, etc. As the intermediate layer, one or more layers can be appropriately selected from a reinforcing layer, a gas barrier layer, a light-shielding layer, a printing layer, etc.

[0038] The substrate layer 2, the sealant layer 3, and other layers are preferably formed into a film. The method for forming the film constituting the substrate layer 2, the sealant layer 3, and other layers is not particularly limited, but extrusion is preferred. Examples of extrusion include T-die molding and inflation molding, with T-die molding being particularly preferred. It is more preferred to heat-treat the film with a cooling roll after T-die molding. Alternatively, the film may be melt-extruded simultaneously with adjacent layers by co-extrusion to form a film. When continuously forming a long film, it is preferable to wind up the long film after molding, as this provides excellent productivity. Furthermore, the strength and heat distortion resistance of the film can be improved by uniaxially or biaxially stretching the formed film before lamination.

[0039] The method for producing the laminated film 1 is not particularly limited, and the layers constituting the laminated film 1 can be appropriately laminated by extrusion lamination, dry lamination, co-extrusion, or a combination of these. The thickness of the base layer 2 of the laminated film 1 depends on the intended use of the packaging material and is not particularly limited, but is usually about 10 μm to 200 μm, and preferably 15 μm to 120 μm. The thickness of the sealant layer 3 may be, for example, 10 μm to 50 μm.

[0040] Fig. 2 is a schematic diagram of a packaging bag 10 according to one embodiment. The packaging bag 10 is formed using the laminate film 1 of this embodiment. As shown in Fig. 2, the packaging bag 10 has a bag-shaped body 11 formed from the laminate film 1 and a mouth 12 joined to at least one location on the periphery of the body 11. The shape of the body 11 is not particularly limited, and examples include a three-sided bag, a four-sided bag, a seamed bag, a gusset bag, and a stand-up pouch. The body 11 may also be a large packaging bag, such as an inner bag for a bag-in-box.

[0041] The material for the mouth portion 12 can be suitably used as long as it can be bonded to the sealant layer 3 of the laminate film 1 that constitutes the packaging bag 10 to ensure airtightness, but it is preferably a resin that can be heat-sealed to the sealant layer 3 of the laminate film 1. This allows the mouth portion 12 and the laminate film 1 to be bonded by heat sealing. For this reason, the material for the mouth portion 12 is preferably a polyethylene terephthalate resin, and more preferably an isophthalic acid-modified polyethylene terephthalate resin. This allows the mouth portion 12 to be easily heat-sealed to the sealant layer 3 of the laminate film 1 and also improves the gas barrier properties of the packaging bag 10.

[0042] When heat-sealing the laminate film 1 and the mouth portion 12, the laminate film 1 may be overlapped with the sealant layer 3 on the inside, and the mouth portion 12 may be inserted between the overlapping sealant layers 3 and heat-sealed. Alternatively, a flange or a boat-shaped fusion base may be provided at one end of the mouth portion 12, and this flange or fusion base may be heat-sealed to the periphery of a hole provided in the laminate film 1 or to the inner surface of the opening of a packaging bag. [Example]

[0043] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[0044] The raw materials were blended in the proportions shown in Table 1, melt-kneaded, and then extrusion-molded using a T-die extruder to obtain a film with a thickness of 100 μm. Details of the raw materials shown in Table 1 are as follows.

[0045] (A) Liquid crystal polymer A-1: Low-melting-point liquid crystal polymer (product name "UENO LCP (registered trademark) A-8100", manufactured by Ueno Pharmaceutical Co., Ltd., density ρ = 1.40 g / cm 3 , melting point Tm=220℃)

[0046] (B) Modified polyethylene terephthalate (modified PET) B-1: Isophthalic acid modified polyethylene terephthalate (copolymerization ratio of isophthalic acid component in dicarboxylic acid component: 12 mol%, density ρ = 1.34 g / cm 3 , melting point Tm = 224 ° C, intrinsic viscosity IV = 0.80 dl / g) B-2: Isophthalic acid modified polyethylene terephthalate (copolymerization ratio of isophthalic acid component in dicarboxylic acid component: 23 mol%, density ρ = 1.34 g / cm 3 , intrinsic viscosity IV=0.68dl / g) B-3: Neopentyl glycol-modified polyethylene terephthalate (trade name "Bellpet (registered trademark) E-03", manufactured by Bell Polyester Products, Inc., density ρ = 1.29 g / cm 3 , intrinsic viscosity IV=0.83dl / g)

[0047] (C) Polyethylene terephthalate (PET) Unmodified polyethylene terephthalate (density ρ = 1.34 g / cm 3 , melting point Tm = 260 ° C, intrinsic viscosity IV = 0.75 dl / g)

[0048] (D) Polyethylene (PE) High density polyethylene (density ρ = 0.949 g / cm 3 , Melting point Tm = 130°C, Melt flow rate MFR = 1.1g / 10min (190°C, 2.16kgf)

[0049] The melt flow rate (MFR) is the value (g / 10 min) at a test temperature of 190°C and a nominal load of 2.16 kg. The intrinsic viscosity is the value (dl / g) measured at 30°C in a mixed solvent of phenol and 1,1,2,2-tetrachloroethane in a mass ratio of 1:1.

[0050] [Table 1]

[0051] Next, the obtained films were evaluated as follows.

[0052] (oxygen gas permeability, water vapor permeability) The oxygen gas permeability and water vapor permeability of the prepared film were measured in accordance with JIS K 7126-1 and JIS K 7129.

[0053] (tensile modulus) The tensile modulus of the film in the machine direction and width direction was measured with a sample width of 15 mm, a gripping distance of 50 mm, and a pulling speed of 300 mm / min.

[0054] (tear strength) A 75 mm long slit was made in the center of a sample cut to a length of 150 mm and a width of 50 mm, and the tear strength in the machine direction was measured by the trouser method with a gripping distance of 50 mm and a pulling speed of 200 mm / min.

[0055] (processability) The film-forming properties of the raw material for the film were confirmed when it was extruded using a T-die extruder, and the winding operability of the obtained film was confirmed. The overall evaluation of film-forming properties and winding operability was made based on the following evaluation criteria: A: good, B: somewhat poor, C: poor.

[0056] The evaluation results are shown in Table 2.

[0057] [Table 2]

[0058] As shown in Table 2, the films of Examples 1 to 7 had an oxygen permeability of 0.4 cc / m 2 ·day·atm or less, water vapor permeability is 0.1 (g / m 2 ·days), and it was confirmed that the films of Examples 1 to 7 had excellent gas barrier properties almost equivalent to those of the film of Comparative Example 1 made of a liquid crystal polymer alone. It was also confirmed that the films of Examples 1 to 7 had excellent tear strength, as well as excellent tensile modulus in the machine direction and tensile modulus in the width direction. Furthermore, the films of Examples 1 to 7 also had good processability (film-forming ability and winding operability).

[0059] The film of Comparative Example 1 had excellent gas barrier properties (oxygen permeability and water vapor permeability), but poor tear strength. Furthermore, the film of Comparative Example 1 intermittently tore in the machine direction during the film winding operation, making stable processing impossible and resulting in poor processability. The film of Comparative Example 2 had good tensile modulus in the width direction, tear strength, and processability, but was inferior in gas barrier properties and tensile modulus in the machine direction compared to the films of Examples 1 to 7. The film of Comparative Example 3 had a water vapor permeability of 0.1 (g / m 2 ·day). The film of Comparative Example 4 was significantly inferior in gas barrier properties compared to the films of Examples 1 to 7, and also had a large neck-in when the raw material for the film was extruded using a T-die extruder, narrowing the width of the film from which samples could be taken, and exhibiting poor film formability. The film of Comparative Example 5 was significantly inferior in gas barrier properties compared to the films of Examples 1 to 7, and in particular, had almost no oxygen barrier properties.

[0060] Furthermore, using the films of Examples 1 to 7 as the base layer and modified PET (B-2) as the sealant layer, a co-extruded two-layer film was produced, and then a three-pack sealed bag was produced at a heat sealing temperature of 170°C, a sealing pressure of 0.2 MPa, and a sealing time of 1 second, and it was confirmed that the packaging bag could be produced without any problems. [Explanation of symbols]

[0061] 1. Laminated film 2 Base material layer 3 Sealant Layer 10 packaging bags 11 Torso 12 Mouth

Claims

1. A substrate layer and a sealant layer that forms one of the outermost surfaces, the base layer contains a liquid crystal polymer and a modified polyethylene terephthalate, The modified polyethylene terephthalate is a laminated film containing at least one of isophthalic acid-modified polyethylene terephthalate modified with isophthalic acid and polyethylene terephthalate modified with a diol having two alkyl groups.

2. A substrate layer and a sealant layer that forms one of the outermost surfaces, the base layer contains a liquid crystal polymer and a modified polyethylene terephthalate, The sealant layer is a laminated film containing isophthalic acid-modified polyethylene terephthalate modified with isophthalic acid.

3. The laminate film according to claim 2, wherein the modified polyethylene terephthalate comprises at least one of isophthalic acid-modified polyethylene terephthalate modified with isophthalic acid and polyethylene terephthalate modified with a diol having two alkyl groups.

4. 4. The laminated film according to claim 1, wherein the polyethylene terephthalate modified with a diol having two alkyl groups is neopentyl glycol-modified polyethylene terephthalate modified with neopentyl glycol.

5. the modified polyethylene terephthalate is the isophthalic acid-modified polyethylene terephthalate, 5. The laminated film according to claim 1, wherein the copolymerization ratio of the isophthalic acid component in the dicarboxylic acid component constituting the isophthalic acid-modified polyethylene terephthalate is 3 mol % to 30 mol %.

6. The content of the liquid crystal polymer relative to the base layer is 78 parts by mass to 99 parts by mass, and the content of the isophthalic acid-modified polyethylene terephthalate relative to the base layer is 1 part by mass to 22 parts by mass. The laminate film according to claim 5.

7. the modified polyethylene terephthalate is the neopentyl glycol-modified polyethylene terephthalate, The laminate film according to claim 4, wherein the content of the liquid crystal polymer relative to the base layer is 83 parts by mass to 99 parts by mass, and the content of the neopentyl glycol-modified polyethylene terephthalate relative to the base layer is 1 part by mass to 17 parts by mass.

8. The laminated film according to claim 1 , wherein the sealant layer contains at least one of a polyethylene resin, a polypropylene resin, a polyester resin, and a cyclic olefin resin.

9. 9. The laminated film according to claim 8, wherein the polyester resin is an isophthalic acid-modified polyethylene terephthalate modified with isophthalic acid.

10. a layer provided on the opposite side of the base layer from the sealant layer; The laminated film according to claim 1 , wherein the other layer contains a resin other than a liquid crystal polymer.

11. The laminated film according to any one of claims 1 to 10, wherein the substrate layer is formed into a film by extrusion molding.

12. A packaging bag formed using the laminated film according to any one of claims 1 to 11.

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