Packaging laminated film

Abstract

To provide a laminate film for packaging capable of sealing stably at a high heat seal strength while reducing an occurrence of a pinhole at transportation.SOLUTION: A gas barrier film 12 and a sealant film 13 are laminated interposing a resin 1b melted and extruded therebetween to obtain a laminate film 10 for packaging. The sealant film 13 has a multilayer structure. If a layer located at the outermost surface from among layers composing the sealant film 13 is a seal layer 133, a density of any layer located between the seal layer 133 and the gas barrier film 12 is lower than a density of the seal layer 133.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a laminated film for packaging suitable for packaging heavy objects, such as infusion bags filled with infusion liquids. [Background technology]

[0002] Infusion bags contain drugs that are easily degraded by oxygen, such as amino acid solutions and sugar / electrolyte solutions, as well as drugs that are easily degraded by light, such as vitamins.However, because these drugs are injected directly into the body, additive-free plastic containers are often used as the primary container.Since additive-free plastic containers do not have oxygen barrier or light-blocking properties, exterior packaging bags that have oxygen barrier and light-blocking properties are often used as the secondary container to store the primary container.

[0003] For example, Patent Document 1 describes a technology in which an exterior packaging bag is constructed from a laminated film formed by laminating, from the outside, a base film, a gas barrier film, and a sealant film, and an infusion bag is stored inside the exterior packaging bag. The gas barrier film is a vapor-deposited film on which aluminum is vapor-deposited. Vapor-deposited aluminum films have excellent barrier properties against various gases such as oxygen gas and water vapor, and also have excellent light-blocking properties. As a result, the medicine or medicinal solution inside the infusion bag is protected from various gases and radiation such as ultraviolet rays.

[0004] The gas barrier film and the sealant film are laminated by the so-called melt extrusion lamination method. That is, a molten resin is extruded from an extruder, and while the molten resin still has adhesive properties, a gas barrier film and a sealant film are laminated on both sides of the molten resin and pressure-bonded to form an integrated film. Low-density polyethylene is generally used as the melt-extruded resin.

[0005] However, this infusion bag is heavy, and when such heavy contents are packed in a packaging bag and transported, the vibrations caused during transportation cause the laminated film to repeatedly bend, and the laminated film may collide or rub against each other, resulting in pinholes in the laminated film.

[0006] In order to prevent the occurrence of such pinholes, Patent Document 1 proposes a packaging laminate film using a biaxially oriented ethylene copolymer film as the sealant film. The biaxially oriented ethylene copolymer film itself has heat-sealability, despite being biaxially oriented. Therefore, this biaxially oriented ethylene copolymer film has high physical strength and high impact resistance, so that even when the film contains heavy objects such as those mentioned above and is subjected to vibrations or collisions with the surroundings during transportation, pinholes are unlikely to occur.

[0007] However, although biaxially stretched ethylene copolymer films have heat-sealing properties, they are crystallized by biaxial stretching, and therefore high heat-sealing strength cannot be expected, and the film has poor stability. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 2018-30313 Summary of the Invention [Problem to be solved by the invention]

[0009] Therefore, an object of the present invention is to provide a laminated film for packaging that reduces the occurrence of pinholes during transportation and that can be stably sealed with high heat seal strength. [Means for solving the problem]

[0010] That is, the invention described in claim 1 is a packaging laminate film including a gas barrier film and a sealant film, the gas barrier film and the sealant film being laminated with a melt-extruded resin therebetween, The sealant film has a multilayer structure, This is a packaging laminate film characterized in that when the outermost layer of each layer constituting this sealant film is a sealing layer, the density of any layer located between this sealing layer and the gas barrier film is lower than the density of the sealing layer.

[0011] Next, the invention described in claim 2 is characterized in that the density of the sealing layer is 0.93 to 0.94 g / cm 3 and the density of any layer located between the sealing layer and the gas barrier film is in the range of 0.85 to 0.92 g / cm. 3 2. The packaging laminate film according to claim 1, characterized in that the film thickness is in the range of 0.1 to 1.0 μm.

[0012] Next, the invention described in claim 3 is the packaging laminate film described in claim 1 or 2, characterized in that the gas barrier film contains a stretched polyester film in its layer structure, and the density of any layer located between the gas barrier film and the film is lower than the density of this stretched polyester film.

[0013] Next, the invention described in claim 4 is characterized in that the density of the stretched polyester film is 1.34 to 1.41 g / cm 3 4. The packaging laminate film according to claim 3, wherein the film thickness is in the range of 0.1 to 1.0 μm.

[0014] Next, a fifth aspect of the present invention is the packaging laminate film according to any one of the first to fourth aspects, characterized in that the gas barrier film has a vapor-deposited metal film in its layer structure.

[0015] Next, a sixth aspect of the present invention is the packaging laminate film according to any one of the first to fifth aspects, characterized in that the gas barrier film has a transmittance of 1% or less for light rays with wavelengths of 200 nm to 800 nm. [Effects of the Invention]

[0016] In the present invention, the density of any layer located between the outermost sealing layer and the gas barrier film is lower than the density of the sealing layer, so that even when a packaging bag made from this laminated packaging film is repeatedly vibrated or bent, the layer located between the sealing layer and the gas barrier film absorbs and cushions the stress caused by the vibration or bending, making it less likely to produce pinholes. Therefore, even when a packaging bag made in this way is used to store heavy items such as infusion bags and transport them, the occurrence of pinholes in the packaging bag can be reduced.

[0017] Furthermore, there is no need to use stretched films for any of the layers constituting the multilayer sealant film, and unstretched films with poor crystallinity can be used, making it possible to achieve stable sealing with high heat seal strength. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a cross-sectional view showing a specific example of the packaging laminate film of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0019] Specific examples of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a cross-sectional view showing a specific example of a packaging laminate film of the present invention. As can be seen from this figure, this packaging laminate film 10 is formed by laminating, from the outside, a base film 11, a gas barrier film 12, and a sealant film 13. The base film 11 and the gas barrier film 12 are laminated by a so-called melt-extrusion lamination method. That is, a molten resin is extruded from an extruder, and while the molten resin still has adhesive strength, the base film 11 and the gas barrier film 12 are laminated on both sides of the extruded resin and pressure-bonded to form an integrated laminate. The gas barrier film 12 and the sealant film 13 are also laminated by a so-called melt-extrusion lamination method. In FIG. 1, 1a denotes the melt-extruded resin layer between the base film 11 and the gas barrier film 12, and 1b denotes the melt-extruded resin layer between the gas barrier film 12 and the sealant film 13.

[0020] Any plastic film can be used as the base film 11 used in the laminated film 10 of the present invention, but since the infusion bag to be stored is generally heavy, it is desirable to use a film that has the strength to withstand the storage of such a heavy object and also has processability suitable for manufacturing and processing of packaging bags. Examples of such films include biaxially oriented films with a thickness of 20 to 100 μm. Examples include biaxially oriented polypropylene (OPP) film and biaxially oriented polyester (OPET) film.

[0021] A printed pattern (not shown) can be applied to this base film 11. The printed pattern is preferably applied to a surface that is not exposed on the outer surface of the laminated film 10. This is known as reverse printing. The binder for the printing ink may be any material, but for example, printing ink using a urethane resin as a binder can be used.

[0022] The gas barrier film 12 can be constructed by laminating a metal vapor-deposited film on a plastic film as a vapor-deposited substrate. The metal vapor-deposited film has excellent barrier properties against various gases such as oxygen gas and water vapor, and also has excellent light-blocking properties.

[0023] The deposition substrate may be any plastic film, but it is desirable to use a high-density, hard film to prevent pinholes from occurring when the packaging bag made of this laminated film is repeatedly vibrated or bent. For example, a film with a density of 1.34 to 1.41 g / cm 3 The thickness of the deposition substrate may be, for example, 6 to 16 μm.

[0024] Furthermore, an aluminum vapor deposition film can be preferably used as the metal vapor deposition film. As mentioned above, this metal vapor deposition film ensures light blocking properties as well as blocking properties (barrier properties) against various gases such as oxygen. For this reason, the gas barrier film 12 formed by laminating this metal vapor deposition film on a vapor deposition base desirably has a light transmittance of 1% or less in the wavelength range of 200 to 800 nm. A film with this level of light transmittance will have sufficient gas barrier properties. Note that this metal vapor deposition film can also be formed by vacuum deposition or by sputtering or other methods.

[0025] Next, the melt-extruded resin layer 1a, which is interposed between the base film 11 and the gas barrier film 12 and adhesively laminates them together, can be made of a polyethylene resin such as low-density polyethylene resin (LDPE) or linear low-density polyethylene (LLDPE). As described above, this polyethylene resin is extruded from an extruder in a molten state, and while the molten polyethylene resin still has adhesive strength, the base film 11 and the gas barrier film 12 are extruded on both sides of the molten polyethylene resin. By overlapping and pressing the base film 11 and the gas barrier film 12 together, the whole can be integrated, and the base film 11, melt-extruded resin layer 1a, and gas barrier film 12 can be laminated in this order. A molten polyethylene resin may be extruded between the base film 11 and the gas barrier film 12 and pressed together, or a melt-extruded resin layer 1a may be formed by extruding the resin onto one of the base film 11 and the gas barrier film 12, and then the other film may be pressed together. Furthermore, before pressing the base film 11 and the gas barrier film 12 together, an anchor coat layer may be provided, or a surface treatment such as corona discharge treatment or ozone treatment may be performed.

[0026] Next, when the laminated film 10 is used to manufacture an outer bag, the sealant film 13 constitutes the inner layer thereof and is sealed to each other.

[0027] The sealant film 13 must have a multi-layer structure. Although a two-layer structure is also acceptable, the packaging laminate film 10 shown in Fig. 1 has a three-layer structure.

[0028] Of the layers constituting the sealant film 13, the layer 133 located on the outermost surface is called the "sealing layer," and this sealing layer 133 is the layer located on the innermost layer of the outer packaging bag. The other layers 131 and 132 are layers located between the melt-extruded resin layer 1b and the sealing layer 133. Therefore, for ease of explanation, of these two layers 131 and 132, the layer 131 in contact with the melt-extruded resin layer 1b is called the "laminated layer," and the layer 132 located between the laminated layer 131 and the sealing layer 133 is called the "intermediate layer."

[0029] The lamination layer 131, intermediate layer 132, and seal layer 133 can all be made of a polyolefin resin. However, as described below, the density of the lamination layer 131 and the intermediate layer 132 must be lower than the density of the seal layer 133. Examples of polyolefin resins that can be used to make the layers 131, 132, and 133 include low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), ethylene-vinyl acetate copolymer (EVA), ethylene-methacrylic acid copolymer (EMAA), ethylene-ethyl acrylate copolymer (EAA), ionomer, and polypropylene. These resins can be co-extruded using an extruder to form a multilayer film. An unstretched film with poor crystallinity is preferred.

[0030] A polyolefin resin can be used as the melt-extruded resin layer 1b that is interposed between the gas barrier film 12 and the sealant film 13 and adhesively laminates them together. As will be described later, the density of this melt-extruded resin layer 1b must also be lower than the density of the seal layer 133.

[0031] The polyolefin that constitutes this melt-extruded resin layer 1b is extruded in a molten state from an extruder, and while this molten polyolefin still has adhesive strength, a gas barrier film 12 and a sealant film 13 are superimposed on both sides of it and pressed together to form an integrated whole, with the gas barrier film 12, melt-extruded resin layer 1b, and sealant film 13 laminated in that order.

[0032] The order in which the base film 11, the gas barrier film 12, and the sealant film 13 are laminated is arbitrary. That is, the base film 11 and the gas barrier film 12 may be laminated together first, and then the sealant film 13 may be laminated thereon. Alternatively, the gas barrier film 12 and the sealant film 13 may be laminated together first, and then the base film 11 may be laminated thereon.

[0033] As described above, the density of any layer located between the sealing layer 133 and the gas barrier film 12 must be lower than the density of the sealing layer 133. If the density of these layers is lower than the density of the sealing layer 133, even when a packaging bag made of this packaging laminate film 10 is repeatedly vibrated or bent, these layers located between the sealing layer 133 and the gas barrier film 12 will absorb and buffer the stress caused by the vibration or bending, thereby suppressing the occurrence of pinholes. In this example, the layers located between the sealing layer 133 and the gas barrier film 12 are the melt-extruded resin layer 1b, the lamination layer 131, and the intermediate layer 132. Therefore, the densities of the melt-extruded resin layer 1b, the lamination layer 131, and the intermediate layer 132 must all be lower than the density of the sealing layer 133. For example, when the density of the sealing layer 133 is 0.93 to 0.94 g / cm 3 In this case, the density of the melt-extruded resin layer 1b, the lamination layer 131, and the intermediate layer 132 is 0.85 to 0.92 g / cm 3 It is sufficient if it is within the range of

[0034] As mentioned above, if the density of the layers located between the sealing layer 133 and the gas barrier film 12 (in this example, the melt-extruded resin layer 1b, the lamination layer 131, and the intermediate layer 132) is lower than the density of the vapor deposition substrate of the gas barrier film 12, these lower-density layers 1b, 131, and 132 will be interposed between the higher-density gas barrier film 12 and the sealing layer 133, and these layers will absorb and cushion stress caused by vibration and bending, further reliably reducing the occurrence of pinholes. [Example]

[0035] (Example) A 50 μm thick OPP film (P2161 manufactured by Toyobo Co., Ltd.) was used as the base film 11. A printed image was applied to this base film 11 using a urethane reverse printing ink (LPGT manufactured by Toyo Ink Mfg. Co., Ltd.). The ink thickness was 1 μm.

[0036] The gas barrier film 12 was a vapor-deposited film (manufactured by Oike Pack Materials Co., Ltd.: JC-V8, thickness 12 μm) in which an aluminum vapor-deposited film was laminated on an OPET film used as a vapor-deposited substrate. The density of the OPET film used as a vapor-deposited substrate was 1.40 g / cm. 3 is.

[0037] The sealant film 13 used was a three-layer film in which a lamination layer 131, an intermediate layer 132, and a sealing layer 133 were co-extruded and laminated in this order. The lamination layer 131, the intermediate layer 132, and the sealing layer 133 were all made of LLDPE, and the density of the lamination layer 131 was 0.92 g / cm. 3 , the density of the intermediate layer 132 is 0.90 g / cm 3 , the density of the sealing layer 133 is 0.94 g / cm 3 The thickness of each of the layers 131, 132, and 133 is 20 μm, and the thickness of the sealant film 13 is 60 μm. The sealant film 13 is an unstretched film.

[0038] In addition, LDPE (Sumitomo Chemical Co., Ltd.: Sumikasen 1417) was prepared as a resin for forming the melt-extruded resin layers 1a and 1b. Its density was 0.918 g / cm 3 is.

[0039] The LDPE constituting the melt-extruded resin layer 1a is then extruded in a molten state from an extruder, and while the molten LDPE still has adhesive strength, a base film 11 and a gas barrier film 12 are superimposed on both sides of the molten LDPE and pressed together to laminate them together, and the LDPE constituting the melt-extruded resin layer 1b is extruded in a molten state, and a gas barrier film 12 and a sealant film 13 are superimposed on both sides of the molten LDPE and pressed together to laminate them together.

[0040] The packaging laminate film 10 manufactured by the above steps is, as shown in FIG. 1, The substrate film 11, the melt-extruded resin layer 1a, the gas barrier film 12, the melt-extruded resin layer 1b, the lamination layer 131, the intermediate layer 132, and the seal layer 133 are laminated in this order, and the layer located between the seal layer 133 and the gas barrier film 12 is the melt-extruded resin layer 1b (density 0.918 g / cm 3 ), lamination layer 131 (density 0.92 g / cm 3 ) and intermediate layer 132 (density 0.90 g / cm 3 ), and the density of each layer is the same as that of the sealing layer 133 (density 0.94 g / cm 3 ) smaller than

[0041] The thus obtained laminated packaging film 10 was used to make a four-side sealed bag measuring 390 mm in length and 280 mm in width.

[0042] (Comparative Example) A packaging laminate film 10 was produced in the same manner as in Example, except that the following film was used instead of the sealant film 13, and four-side sealed bags were also produced.

[0043] The film used in place of the sealant film 13 used in the examples has a three-layer structure in which a lamination layer 131, an intermediate layer 132, and a sealing layer 133 are co-extruded and laminated in this order. The lamination layer 131, the intermediate layer 132, and the sealing layer 133 are all made of LLDPE, and the density of the lamination layer 131 is 0.94 g / cm 3 , the density of the intermediate layer 132 is 0.90 g / cm 3 , the density of the sealing layer 133 is 0.94 g / cm 3 The thickness of each of the layers 131, 132, and 133 is 20 μm, and the thickness of the sealant film 13 is 60 μm. The sealant film 13 is an unstretched film.

[0044] That is, the sealant film 13 used in the example and the film used in this comparative example differ in the density of the lamination layer 131. Other points are the same.

[0045] For this reason, among the layers positioned between the sealing layer 133 and the gas barrier film 12, the lamination layer 131 (density 0.94 g / cm 3 ) is the density of the sealing layer 133 (density 0.94 g / cm 3 ) is the same as

[0046] (evaluation) Resistance to vibration and bending was evaluated for the packaging laminate films 10 of Examples 1 to 3 and Comparative Example 1. This evaluation was carried out by the following method.

[0047] That is, first, 1000 ml of water was filled into a four-side sealed bag made with these packaging laminate films 10 and sealed to form a package. These packages were then packed into a cardboard box. The packages were arranged in two rows of 10 bags, and the arranged packages were stacked in multiple layers and placed inside the cardboard box.

[0048] The cardboard box containing the packaged items was then vibrated under the following vibration conditions: acceleration 5G, frequency 11Hz, amplitude 20mm, for one hour.

[0049] After this vibration test, the packages were removed from the cardboard boxes, opened, and the water was drained out. Turpentine oil was then added instead. After storing the packages in this state for 24 hours, the number of pinholes was visually checked. Additionally, the number of packages in which turpentine oil had seeped out onto the outside surface, even though no pinholes were found, was visually checked. The results are shown in Table 1.

[0050] [Table 1]

[0051] From this result, when the density of any layer located between the outermost sealing layer 133 and the gas barrier film 12 is lower than the density of the sealing layer 133, even if the sealant film 13 is an unstretched film, It can be seen that this reduces damage to the packaging laminate film 10 caused by vibration and also reduces the number of pinholes. [Explanation of symbols]

[0052] 10: Laminated packaging film 11: Base film 12: Gas barrier film 13: Sealant film 131: Lamination layer 132: Intermediate layer 133: Sealing layer 1a: Melt-extruded resin layer 1b: Melt-extruded resin layer

Claims

1. A packaging laminate film comprising a gas barrier film and a sealant film, the gas barrier film and the sealant film being laminated together with a melt-extruded resin interposed therebetween, The sealant film has a multilayer structure, When the outermost layer of the sealant film is a sealing layer, the density of any layer located between the sealing layer and the gas barrier film is lower than the density of the sealing layer, a base film is laminated via a resin on a surface of the gas barrier film opposite to the sealant film side; the base film is a biaxially oriented polyester film, The sealant film includes, in order from the gas barrier film side, a lamination layer, an intermediate layer, and the seal layer, A packaging laminated film, characterized in that the density of the intermediate layer is lower than the density of the lamination layer.

2. The density of the sealing layer is 0.93 to 0.94 g / cm ３ and the density of any layer located between the sealing layer and the gas barrier film is in the range of 0.85 to 0.92 g / cm ３ 2. The packaging laminate film according to claim 1, wherein the thickness of the film is in the range of 100 μm to 150 μm.

3. 3. The packaging laminate film according to claim 1, wherein the gas barrier film contains a stretched polyester film in its layer structure.

4. The density of the stretched polyester film is 1.34 to 1.41 g / cm ３ 4. The packaging laminate film according to claim 3, wherein the thickness of the film is in the range of 100 μm to 150 μm.

5. 5. The packaging laminate film according to claim 1, wherein the gas barrier film has a vapor-deposited metal film in its layer structure.

6. 6. The packaging laminate film according to claim 1, wherein the gas barrier film has a light transmittance of 1% or less in the wavelength range of 200 to 800 nm.

7. 7. The packaging laminate film according to claim 1, wherein the sealing layer does not contain a light-shielding material.

8. 8. The packaging laminate film according to claim 1, wherein the sealing layer is made of polyethylene alone.

9. A packaging laminate film described in any one of claims 1 to 8, characterized in that the lamination layer, the intermediate layer, and the sealing layer are each formed of ethylene-vinyl acetate copolymer, ethylene-methacrylic acid copolymer, ethylene-ethyl acrylate copolymer, or ionomer.

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