Barrier Films and Pouches

Abstract

To provide a barrier film and a pouch that have excellent both recyclability and barrier properties.SOLUTION: A barrier film 1000 comprises a first linear low-density polyethylene layer 101, a second linear low-density polyethylene layer 102, and a barrier layer 301 between the first linear low-density polyethylene layer 101 and the second linear low-density polyethylene layer 102. The barrier layer 301 contains a water-soluble resin and inorganic particles. A content of a material other than polyethylene is 5 mass% or less based on a total mass of the barrier film 1000.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to barrier films and pouches. [Background technology]

[0002] Pouches are used as packaging materials in various fields such as food and toiletries. In general, pouches are formed into a bag shape by heat sealing a laminate of plastic films formed by laminating plastic films of multiple different materials. In addition, pouches have barrier properties against the permeation of water vapor and / or oxygen to suppress the release, moisture absorption, deterioration, or leakage of odors of the contents.

[0003] Patent Document 1 discloses a barrier film that reduces water vapor and oxygen transmission rates and can be used to package food and other commercial products for long periods of time without any deterioration.

[0004] The barrier film disclosed in Patent Document 1 is a recyclable barrier film that includes a first layer including high density polyethylene and a barrier layer including a polymer other than polyethylene. The polymer included in the barrier layer acts to reduce oxygen permeability through the barrier film compared to the oxygen permeability through the first layer. The barrier layer is present in the barrier film in an amount of less than 5 weight percent based on the total weight of the barrier film. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 2017-518205 Summary of the Invention [Problem to be solved by the invention]

[0006] In recent years, the problem of plastic waste, which is discarded plastic products such as pouches and flows into the ocean through rivers, has been attracting attention. Plastic waste may have a negative impact on the natural environment by drifting in the ocean.

[0007] One effective way to reduce such plastic waste is thought to be to recycle discarded plastic products.

[0008] However, when plastic products such as pouches that contain a plastic film of a different material in addition to the main plastic film are recycled into recycled resin pellets, the recycled resin pellets obtained by recycling contain the different materials, so that the desired recycled product cannot be manufactured from the recycled resin pellets. Therefore, plastic materials that contain a large amount of different materials tend to have low suitability for recycling.

[0009] In response to this, various attempts have been made to reduce the content of foreign materials in plastic films, but the foreign materials are used to improve the quality of the plastic film, for example, by improving the barrier property. Therefore, by reducing the content of foreign materials in a plastic film, problems such as a decrease in the barrier property of the plastic film arise. Therefore, there is a demand for plastic films that are excellent in both recyclability and barrier property. [Means for solving the problem]

[0010] According to an embodiment disclosed herein, it is possible to provide a barrier film comprising a first linear low density polyethylene layer, a second linear low density polyethylene layer, and a barrier layer between the first linear low density polyethylene layer and the second linear low density polyethylene layer, wherein the barrier layer contains a water-soluble resin and inorganic particles, and the content of materials other than polyethylene is 5 mass % or less of the total mass of the barrier film.

[0011] According to an embodiment disclosed herein, a pouch including the above-described barrier film can be provided. Effect of the Invention

[0012] According to the embodiments disclosed herein, it is possible to provide a barrier film and a pouch that are excellent in both recyclability and barrier properties. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic cross-sectional view of a barrier film according to an embodiment. [Diagram 2] FIG. 2 is a schematic plan view illustrating a method for measuring a Vicat softening point. [Diagram 3] 1 is a flowchart of a manufacturing process of an example of a method for manufacturing a barrier film according to an embodiment. [Figure 4] FIG. 2 is a schematic cross-sectional view of a barrier film manufactured by another example of the method for manufacturing a barrier film. [Diagram 5] FIG. 2 is a schematic perspective view of a pouch according to an embodiment. [Figure 6] FIG. 1 is a diagram showing the relationship between the sealing temperature and the sealing strength of the barrier film in the experimental example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment will be described. In the drawings used in the description of the embodiment, the same reference numerals denote the same or corresponding parts.

[0015] <Barrier film structure> 1 shows a schematic cross-sectional view of a barrier film 1000 of an embodiment. The barrier film 1000 includes a first linear low-density polyethylene layer (hereinafter referred to as the "first layer") 101, a second linear low-density polyethylene layer (hereinafter referred to as the "second layer") 102, and a barrier layer 301 between the first layer 101 and the second layer 102.

[0016] The barrier film 1000 also includes a first anchor coat layer 201 between the first layer 101 and the barrier layer 301, and a second anchor coat layer 202 between the second layer 102 and the barrier layer 301. The barrier film 1000 also includes a third linear low density polyethylene layer (hereinafter referred to as the "third layer") 103 between the second layer 102 and the second anchor coat layer 202.

[0017] <1st layer> The first layer 101 may contain polyethylene such as high density polyethylene (HDPE), low density polyethylene (LDPE), or both, so long as it contains linear low density polyethylene (hereinafter referred to as "LLDPE") in an amount of 50% or more by mass of the entire first layer 101. From the viewpoint of increasing the transparency and strength of the barrier film 1000, the first layer 101 preferably contains LLDPE in an amount of 60% or more by mass of the entire first layer 101, more preferably contains 70% or more by mass, even more preferably contains 80% or more by mass, and particularly preferably contains 90% or more by mass. As the content of LLDPE in the first layer 101 increases, the material of the recycled resin pellets obtained by recycling the barrier film 1000 tends to be unified into LLDPE, and therefore the recyclability of the barrier film 1000 tends to be excellent. be.

[0018] The LLDPE contained in the first layer 101 may be, for example, a conventionally known LLDPE. For example, a conventionally known LLDPE may be an ethylene homopolymer or copolymer having at least one α-olefin. Here, the α-olefin may, for example, have 3 to 20 carbon atoms and a molecular weight of 0.89 g / cm 3 More than 0.94g / cm 3 The density may be less than 0.915 g / cm 3 More than 0.94g / cm 3 Preferably, it is less than 0.915 g / cm 3 More than 0.925g / cm 3More preferably, the α-olefin has, for example, 3 to 20 carbon atoms. The α-olefins may be aliphatic α-olefins, preferably containing 3 to 12 carbon atoms, more preferably 3 to 8 carbon atoms. Particularly suitable α-olefins may be, for example, ethylene, propylene, butene-1,4-methyl-1-pentene, hexene-1 or octene-1; or ethylene in combination with one or more of propylene, butene-1,4-methyl-1-pentene, hexene-1 and octene-1. Conventionally known LLDPE may also be substantially linear apart from short chain branches derived from comonomers. The thickness of the first layer 101 is not particularly limited, but is preferably 20 μm or more and 80 μm or less.

[0019] <2nd layer> The second layer 102 may also contain polyethylene such as HDPE, LDPE, or both, so long as it contains LLDPE at 50% by mass or more of the entire second layer 102. From the viewpoint of increasing the transparency and strength of the barrier film 1000 and improving recyclability, the second layer 102 preferably contains LLDPE at 60% by mass or more of the entire second layer 102, more preferably contains 70% by mass or more, further preferably contains 80% by mass or more, and particularly preferably contains 90% by mass or more. The explanation of the LLDPE contained in the second layer 102 is the same as the explanation of the LLDPE in the first layer 101, and therefore will not be repeated here. The thickness of the second layer 102 is not particularly limited, but is preferably 20 μm or more and 150 μm or less.

[0020] <Barrier layer> The barrier layer 301 contains a water-soluble resin and inorganic particles. The barrier layer 301 is a different material from the polyethylene, such as LLDPE, contained in the first layer 101 and the second layer 102. However, when the barrier layer 301 contains a water-soluble resin, it becomes possible to easily remove or reduce the barrier layer 301 from the barrier film 1000, for example, by heat treatment, water treatment, or the like. This makes it more likely that the material of the recycled resin pellets obtained by recycling the barrier film 1000 will be unified to polyethylene, and the recyclability of the barrier film 1000 tends to be excellent. Therefore, from the viewpoint of improving the recyclability of the barrier film 1000, it is preferable that the resin of the barrier layer 301 does not contain any resin other than the water-soluble resin and contains only the water-soluble resin.

[0021] A conventionally known water-soluble resin can be used as the water-soluble resin contained in the barrier layer 301. An example of a conventionally known water-soluble resin is polyvinyl alcohol (PVA). PVA is preferable because of its excellent gas barrier properties.

[0022] The barrier layer 301 contains inorganic particles. When the barrier layer 301 contains inorganic particles, the barrier film 1000 tends to have improved barrier properties against oxygen permeation (hereinafter referred to as "oxygen barrier properties") and / or barrier properties against water vapor permeation (hereinafter referred to as "water vapor barrier properties").

[0023] As the inorganic particles, for example, an inorganic layered compound can be used. may be a layered structure formed by stacking unit crystal layers. Examples of inorganic layered compounds that can be used include graphite, phosphate derivative compounds (zirconium phosphate compounds, etc.), chalcogenides, hydrotalcite compounds, lithium aluminum composite hydroxides, and clay minerals. Examples of clay minerals that can be used include kaolinite-serpentine clay minerals such as kaolinite, talc-pyrophyllite clay minerals such as talc, smectite clay minerals such as montmorillonite, vermiculite clay minerals, mica clay minerals such as tetrasilylic mica, brittle mica clay minerals such as xanthophyllite, and chlorite clay minerals such as clinochlore.

[0024] From the viewpoint of improving the oxygen barrier property and / or water vapor barrier property of the barrier film 1000, it is preferable to form the barrier layer 301 from EXCEVIER (registered trademark) manufactured by Sumitomo Chemical Co., Ltd. EXCEVIER (registered trademark) is a water-soluble resin composition containing PVA as a water-soluble resin and montmorillonite as inorganic particles. When the barrier layer 301 is formed by heating EXCEVIER (registered trademark), the inorganic particles are regularly aligned by the heating, and it is said that the oxygen barrier property and / or water vapor barrier property of the barrier layer 301 is improved. In addition, the oxygen barrier property and water vapor barrier property of the barrier layer 301 containing the cured PVA can also be improved by the heating.

[0025] Montmorillonite is an inorganic particle having a unit crystal layer with a sandwich structure in which one octahedral sheet is sandwiched between two tetrahedral sheets, the unit crystal layer comprising tetrahedral sheets in which silicon and oxygen tetrahedra are connected in sheet form and octahedral sheets in which aluminum and hydroxyl octahedra are connected in sheet form.

[0026] For example, materials other than polyethylene, such as water-soluble resins and inorganic particles, contained in the barrier layer 301 constitute 5 mass % or less of the total mass of the barrier film 1000. This allows the barrier film 1000 to have high recyclability. From the viewpoint of improving recyclability, materials other than polyethylene are preferably contained in the barrier film 1000 at 4 mass % or less, more preferably 3 mass % or less, even more preferably 2 mass % or less, and particularly preferably 1 mass % or less. Here, materials other than polyethylene refer to materials different from conventionally known polyethylenes, such as LLDPE, HDPE, and LDPE.

[0027] <3rd layer> The barrier film 1000 may include a third layer 103. The third layer 103 may also include polyethylene, such as HDPE, LDPE, or both, so long as the third layer 103 contains LLDPE in an amount of 50% by mass or more of the entire third layer 103. From the viewpoint of increasing the transparency and strength of the barrier film 1000, the third layer 103 preferably contains LLDPE in an amount of 60% by mass or more of the entire third layer 103, more preferably contains 70% by mass or more, further preferably contains 80% by mass or more, and particularly preferably contains 90% by mass or more. The explanation of the LLDPE contained in the third layer 103 is the same as the explanation of the LLDPE contained in the first layer 101 and the second layer 102, and therefore will not be repeated here.

[0028] From the viewpoint of reducing deformation of the barrier film 1000 due to heat sealing (hereinafter also referred to as "seal deformation"), the Vicat softening point of the third layer 103 is preferably not less than 85° C., more preferably not less than 90° C., even more preferably not less than 95° C., and particularly preferably not less than 100° C. There is no particular upper limit to the Vicat softening point of the third layer 103, but it is preferably a Vicat softening point suitable for the extrusion lamination method described below, for example.

[0029] In this specification, the "Vicat softening point" refers to the point at which the third layer 103 begins to soften rapidly. Hereinafter, a method for measuring the Vicat softening point will be described with reference to the schematic plan view of FIG.

[0030] First, as shown in Fig. 2, a test piece 403 of the third layer 103 to be measured is placed on a base 401. Next, as shown in Fig. 2, a test piece 403 is placed on the base 401 so that the contact area with the surface of the test piece 403 is 1 mm 2 The indenter 402 is placed on the surface of the test piece 403 so that:

[0031] Next, a load (50 N / mm) was applied to the indenter 402 placed on the surface of the test piece 403 in the direction indicated by the arrow 404 in FIG. 2 ) is applied to the test piece 40 by the indenter 402. With the load applied to the surface of 3, the temperature of the test piece 403 is increased at a heating rate of 50° C. / hour. The temperature of the test piece 403 when the indenter 402 penetrates 1 mm into the test piece 403 is defined as the Vicat softening point.

[0032] From the viewpoint of suppressing deformation of the barrier film 1000 after heat sealing, the durometer hardness HDD of the third layer 103 is preferably 50 HDD or more, and more preferably 55 HDD or more. There is no particular upper limit to the durometer hardness HDD of the third layer 103, but a durometer hardness HDD suitable for various manufacturing methods of the barrier film 1000 can be appropriately selected, for example.

[0033] The durometer hardness HDD of the third layer 103 is measured in accordance with JIS K 7215-1986.

[0034] <First anchor coat layer> For example, a conventionally known anchor coat layer can be used as the first anchor coat layer 201. As the first anchor coat layer 201, it is preferable to use a material that enhances the bonding strength between the first layer 101 and the barrier layer 301.

[0035] <Second anchor coat layer> For example, a conventionally known anchor coat layer can be used as the second anchor coat layer 202. As the second anchor coat layer 202, it is preferable to use a material that enhances the bonding strength between the third layer 103 and the barrier layer 301.

[0036] <Barrier film manufacturing method> 3 shows a flowchart of manufacturing steps of an example of a method for manufacturing the barrier film 1000. As shown in FIG. 3, the example of a method for manufacturing the barrier film 1000 includes a step S10 of forming a barrier layer 301 on the first layer 101, and a step S20 of forming a second layer 102 on the barrier layer 301.

[0037] Hereinafter, a first manufacturing method (extrusion lamination method) which is one example of the manufacturing method of the barrier film 1000, and a second manufacturing method (dry lamination method) which is another example of the manufacturing method of the barrier film 1000 will be described.

[0038] <First manufacturing method (extrusion lamination method)> (1-1) First, a first anchor coat layer 201 is formed on a first layer 101. The method for forming the first anchor coat layer 201 is not particularly limited, and a conventionally known coating method such as gravure coating can be used.

[0039] (1-2) Next, a water-soluble resin composition (hereinafter, referred to as a "barrier layer precursor") that is a precursor of the barrier layer 301 is applied onto the first anchor coat layer 201. The method for forming the barrier layer precursor is not particularly limited, and may be a conventionally known coating method such as gravure coating. A tagging method can be used.

[0040] (1-3) Next, the barrier layer precursor as the heated object is heated to form the barrier layer 301 on the first anchor coat layer 201. The method of heating the barrier layer precursor is not particularly limited as long as it can form the barrier layer 301, but from the viewpoint of improving the barrier properties of the barrier layer 301 while suppressing thermal damage to other layers, it is preferable to heat the barrier layer precursor at a temperature of 40° C. or more and 80° C. or less. A drying process using a drying furnace can be performed to volatilize the solvent contained in the barrier layer precursor to form a coating, and the drying process may be a step of heating the barrier layer precursor.

[0041] Through the above steps (1-1) to (1-3), step S10 of forming barrier layer 301 on first layer 101 is completed.

[0042] (1-4) Next, the second anchor coat layer 202 is formed on the barrier layer 301. The method for forming the second anchor coat layer 202 is also not particularly limited, and any conventionally known coating method such as gravure coating can be used.

[0043] (1-5) Next, using an extrusion device, the resin constituting the third layer 103 is extruded from a T-die between the laminate of the first layer 101, the first anchor coat layer 201, the barrier layer 301, and the second anchor coat layer 202, and the second layer 102. As a result, the resin constituting the third layer 103 is sandwiched between the second anchor coat layer 202 and the second layer 102 of the laminate, and the second layer 102 is bonded onto the second anchor coat layer 202.

[0044] The above steps (1-4) and (1-5) complete step S20 of forming the second layer 102 on the barrier layer 301. In this manner, the barrier film 1000 shown in FIG.

[0045] In the above, the case where the barrier layer precursor is heated in the step (1-3) to form the barrier layer 301 has been described, but apart from or in addition to the step (1-3), the barrier layer precursor may be heated in steps (1-4) and / or (1-5) to form the barrier layer 301. By heating the barrier layer 301 multiple times at a temperature of 80° C. or less, the barrier properties of the barrier layer 301 can be further improved.

[0046] <Second manufacturing method (dry lamination method)> (2-1) First, a first anchor coat layer 201 is formed on a first layer 101 in the same manner as in the first manufacturing method.

[0047] (2-2) Next, a barrier layer precursor is applied onto the first anchor coat layer 201 in the same manner as in the first manufacturing method.

[0048] (2-3) Next, similarly to the first manufacturing method, a barrier layer precursor as an object to be heated is heated to form a barrier layer 301 on the first anchor coat layer 201. The method of heating the barrier layer precursor is not particularly limited as long as it can form the barrier layer 301, but from the viewpoint of improving the barrier properties of the barrier layer 301 while suppressing thermal damage to other layers, it is preferable to heat the barrier layer precursor at a temperature of 40°C or higher and 80°C or lower.

[0049] Through the above steps (2-1) to (2-3), step S10 of forming barrier layer 301 on first layer 101 is completed.

[0050] (2-4) Next, an adhesive layer precursor, which is a precursor of the adhesive layer, is formed on the barrier layer 301. The method for forming the adhesive layer precursor is not particularly limited, and for example, a conventionally known coating method such as gravure coating can be used. The adhesive layer precursor is not particularly limited as long as it can form an adhesive layer, and a conventionally known adhesive layer precursor can be used. However, from the viewpoint of improving the recyclability of the barrier film 1000 by reducing foreign materials, it is preferable to use an adhesive layer precursor capable of forming an olefin-based adhesive layer.

[0051] (2-5) Next, an adhesive layer is formed by removing unnecessary solvent from the adhesive layer precursor. The adhesive layer can be formed, for example, by passing the laminate after the formation of the adhesive layer precursor through a drying oven to dry the adhesive layer precursor. In the second manufacturing method, an adhesive layer is formed in place of the second anchor coat layer 202 and the third layer 103 in the first manufacturing method.

[0052] (2-6) Next, the second layer 102 is pressed onto the adhesive layer, thereby bonding the second layer 102 onto the adhesive layer.

[0053] The above steps (2-4) to (2-6) complete the step S20 of forming the second layer 102 on the barrier layer 301. In this manner, the barrier film 1000 shown in FIG.

[0054] 4 shows a schematic cross-sectional view of a barrier film 1000 produced by the second manufacturing method. As shown in FIG. 4, in the barrier film 1000 produced by the second manufacturing method, the second layer 102 is bonded to the barrier layer 301 via the adhesive layer 203.

[0055] In the above, the barrier layer precursor is heated to form the barrier layer 301 and then the adhesive layer precursor is applied, but it is also possible to form an adhesive layer on the barrier layer 301 by applying the adhesive layer precursor onto the barrier layer precursor before the barrier layer 301 is formed and heating the barrier layer precursor and the adhesive layer precursor.

[0056] Comparing the above first and second manufacturing methods, the first manufacturing method is considered to tend to reduce the thermal damage suffered by the first layer 101 compared to the second manufacturing method because the first manufacturing method can shorten the length of the drying oven through which the first layer 101 passes.

[0057] <Properties of Barrier Film> From the viewpoint of reducing the occurrence of pitch deviation during printing and bag making of a pouch using the barrier film 1000, the tensile modulus of the barrier film 1000 is 300 N / mm 2 It is preferable that the resistance is 400N / mm or more. 2 More preferably, it is 500N / mm 2 More preferably, it is 600N / mm 2 More preferably, it is equal to or greater than this.

[0058] The tensile modulus of the barrier film 1000 is measured in accordance with JIS K 7161-1:2014 (ISO 527-1:2012).

[0059] Furthermore, from the viewpoint of obtaining a wide stable range of seal strength, the temperature difference between the seal start temperature of the first layer 101 and the seal start temperature of the second layer 102 is preferably 30°C or more, more preferably 40°C or more, and even more preferably 50°C or more.

[0060] In the case where the barrier film 1000 has a wide stable region of seal strength, for example, when the barrier film 1000 is used to manufacture a pouch (sealing the barrier film 1000 to each other), When applying heat to the sealing bar, it is possible to prevent the resin from sticking to the heated seal bar (sealing mold) by arranging a layer with a high seal rise temperature on the seal surface. If it is possible to prevent the resin from sticking to the seal bar, it is possible to prevent problems such as a decrease in sealing performance and deformation from the expected pouch shape.

[0061] In this specification, the term "seal rise temperature" refers to the temperature at which seal strength is first developed by heating.

[0062] In the barrier film 1000, the first layer 101 may be used as a seal surface layer and the second layer 102 may be used as a sealant layer, or the second layer 102 may be used as a seal surface layer and the first layer 101 may be used as a sealant layer. The seal surface layer has a higher seal start temperature than the sealant layer.

[0063] In this specification, the term "seal surface layer" refers to a layer that comes into contact with a seal bar for heating the barrier film 1000 when the barrier film 1000 is heat-sealed. In addition, in this specification, the term "sealant layer" refers to a layer that is thermally fused by heat sealing the barrier film 1000. Specifically, the pouch is formed by thermally fusion bonding the sealant layers together by heat sealing.

[0064] From the viewpoint of increasing the oxygen barrier property of the barrier film 1000, the oxygen permeability of the barrier film 1000 is set to 3.0 cc / (m 2 24h) or less is preferable, and 2.0cc / (m 2 24h) or less, and 1.0cc / (m 2 24h) or less, and 0.5cc / (m 2 It is especially preferable that the time is within 24 hours. stomach.

[0065] The oxygen permeability of the barrier film 1000 is measured at a temperature of 23°C and a humidity of 65% RT in accordance with JIS K 7126-2:2006 (ISO 15105-2:2003) (Plastics - Films and sheets - Gas permeability test methods - Part 2: isobaric method, Appendix A: Test method for oxygen gas permeability using an electrolytic sensor).

[0066] From the viewpoint of increasing the water vapor barrier property of the barrier film 1000, the water vapor permeability of the barrier film 1000 is set to 3.0 g / (m 2 24h) or less is preferable, and 2.0g / (m 2 24h) or less, and 1.0g / (m 2 24h) or less, and 0.5g / (m 2 It is particularly preferable that the time is 24 hours or less.

[0067] The water vapor permeability of the barrier film 1000 is measured in accordance with JIS Z 0208-1976 under conditions of a temperature of 40° C. and a humidity of 90% RT.

[0068] In the barrier film 1000, materials different from polyethylene account for at least 5 mass % of the total mass of the barrier film 1000. Therefore, since 95 mass % or more of the barrier film 1000 of the embodiment is composed of polyethylene, the barrier film 1000 can be easily recycled. Here, polyethylene includes conventionally known polyethylenes such as LLDPE, HDPE, and LDPE.

[0069] Furthermore, since the resin of the barrier layer 301 made of polyethylene and a different material contains a water-soluble resin, it is possible to realize a barrier film 1000 with excellent recyclability.

[0070] In addition, by not performing high temperature treatment (for example, temperatures exceeding 80° C.) in the manufacturing process of the barrier film 1000, yellowing (heat damage) of the PVA can be suppressed. As a result, the transparency of the barrier film 1000 can be maintained at a high level.

[0071] FIG. 5 shows a schematic perspective view of a pouch 2000 of an embodiment manufactured using the barrier film 1000. Since the pouch 2000 of the embodiment is manufactured using the barrier film 1000, it has excellent oxygen barrier properties and water vapor barrier properties, and is also excellent in recyclability. The pouch 2000 of the embodiment may have a stopper 3000 as shown in FIG. 5, or may have a zipper. When the pouch 2000 of the embodiment has the stopper 3000 or a zipper, it is preferable that the stopper 3000 or the zipper is also made of polyethylene. In addition, for example, when the seal rise temperature of the first layer 101 is higher than the seal rise temperature of the second layer 102, the first layer 101 is disposed on the outside of the pouch 2000, and the second layer 102 is disposed on the inside of the pouch 2000. EXAMPLES

[0072] <Experimental Example 1> First, an anchor coat agent (trade name "Olivine (registered trademark) EL-510-1 / CAT-RT87" manufactured by Toyo-Morton Co., Ltd.) was gravure-coated on a first LLDPE film (trade name "L6100" manufactured by Toyobo Co., Ltd., thickness 70 μm) so that the coating amount after drying was 0.25 g / m 2 Then, heat and dry in a drying oven at about 80℃. As a result, the anchor coating agent was solidified on the first LLDPE film to form a first anchor coating layer.

[0073] Next, a barrier layer precursor ("EXCEVIER (registered trademark)" manufactured by Sumitomo Chemical Co., Ltd.) was gravure coated on the first anchor coat layer so that the coating amount after drying was 1.25 g / m 2 The coating was applied so that the coating was uniform, and the coating was dried by heating in a drying oven at about 80°C. The barrier layer precursor was solidified to form a barrier layer having a thickness of 2 μm on the anchor coat layer of 1. The traveling speed of the first LLDPE film in the drying furnace was about 100 m / min.

[0074] Next, an anchor coat agent (product name "Olivine (registered trademark) EL-510-1 / CAT-RT87" manufactured by Toyo-Morton Co., Ltd.) was applied onto the barrier layer, and heated and dried in a drying oven at about 80° C. As a result, the anchor coat agent solidified on the barrier layer, forming a second anchor coat layer.

[0075] Next, an LLDPE resin (trade name "Yumerit (registered trademark) 021GT" manufactured by Ube Maruzen Polyethylene Co., Ltd.) was extruded from the extruder of the extrusion lamination device through a T-die onto the barrier layer to a thickness of 20 μm, and a second LLDPE film (trade name "L3105" manufactured by Toyobo Co., Ltd., thickness 40 μm) unwound from another unwinding roll was laminated via the extruded LLDPE resin. The Vicat softening point of the extruded LLDPE resin was 95°C, the durometer hardness was 55HDD, and the melting point was 104°C to 116°C.

[0076] This caused the LLDPE resin to solidify, and the second LLDPE film was bonded onto the barrier layer. Thus, the barrier film of the experimental example was produced. The content of materials other than polyethylene in the barrier film of the experimental example was 1.5% of the total mass of the barrier film of the experimental example.

[0077] Next, two sheets of the barrier film of the experimental example prepared as described above were prepared and overlapped so that the surfaces of the second LLDPE film, which was to be the sealant layer, faced each other. After that, a heated seal bar was brought into contact with the first LLDPE film, which was to be the seal surface layer, and heated to apply pressure to the second LLDPE film of the two barrier films. were joined by heat sealing.

[0078] Next, a sample with a width of 15 mm was cut out from the two barrier films joined by heat sealing as described above, and the seal strength (N / 15 mm) was measured in accordance with JIS Z 1707:2019.

[0079] The above operation was repeated while changing the heating temperature of the above-mentioned seal surface layer (hereinafter referred to as "sealing temperature") to measure the seal strength. The sealing pressure was fixed at 0.3 MPa, and the sealing time was fixed at 1 second. The results are shown in Figure 6. In Figure 6, the seal strength of the sealant layer indicated by the solid line indicates the seal strength measured above.

[0080] As shown in Figure 6, the seal rise temperature of the second LLDPE film, which became the sealant layer, was about 80°C. In addition, when the sealing temperature was in the range of about 80°C to about 100°C, the seal strength increased rapidly to about 25 (N / 15mm), and when the sealing temperature was in the range of about 100°C to about 120°C, the seal strength increased gradually from about 25 (N / 15mm). When the sealing temperature exceeded about 120°C, the seal strength decreased to about 25 (N / 15mm), and when the sealing temperature exceeded about 130°C, the seal strength became almost constant at around 25 (N / 15mm).

[0081] As shown in Fig. 6, the seal rise temperature of the seal surface layer was about 130°C. Therefore, the temperature difference between the seal rise temperature of the seal surface layer of the barrier film in the experimental example and the seal rise temperature of the sealant layer was about 50°C. However, when the seal temperature exceeded about 130°C, the seal surface layer stuck to the seal bar and seal shrinkage was observed.

[0082] From the above results, it is believed that the stable region of the seal strength of the barrier film of the experimental example is in the range of about 100°C to about 130°C. The barrier film of the experimental example has such a wide stable region of seal strength, and in this stable region, it exhibits a high seal strength of about 25 (N / 15mm) or more. Therefore, it is believed that the barrier film of the experimental example is a barrier film with excellent heat sealability. Furthermore, taking into consideration the range of the stable region of seal strength, it is estimated that the target seal temperature for the barrier film of the experimental example is in the range of about 110°C to about 120°C.

[0083] <Experimental Example 2> The oxygen permeability of the barrier film of the experimental example was measured together with the oxygen permeability of the laminate (first LLDPE film / first anchor coat layer / barrier layer) before extrusion lamination of the barrier film of the experimental example. The oxygen permeability of the barrier film of the experimental example and the oxygen permeability of the laminate before extrusion lamination of the barrier film of the experimental example were measured under conditions of temperature 23°C and humidity 65%RT in accordance with JIS K 7126-2:2006 (ISO 15105-2:2003) (Plastics-Films and sheets-Test methods for gas permeability-Part 2: Isobaric method, Appendix A: Test method for oxygen gas permeability by electrolytic sensor method). In addition, the water vapor permeability of the laminate before extrusion lamination of the barrier film of the experimental example was measured under conditions of temperature 40°C and humidity 90%RT in accordance with JIS Z 0208-1976. The results are shown in Table 1.

[0084] [Table 1]

[0085] As shown in Table 1, the oxygen permeability of the barrier film in the experimental example was 1.2cc / (m 2 ·twenty four The oxygen permeability of the laminate was 3.0 cc / (m 2 24 hours) Water vapor permeability is 3.0g / (m 2 This is because the barrier layer was heated multiple times. This indicates that the barrier properties are enhanced by heating the barrier layer precursor to dryness and form a barrier layer (first heating). Even at this stage, the laminate has sufficiently high barrier properties (oxygen permeability: 3.0 cc / (m 2 24h) Furthermore, when forming a second anchor coat layer on this barrier layer, the barrier layer is heated in a drying oven at about 80°C (second heating). The barrier film of the experimental example, which was produced by bonding a second LLDPE film to the second anchor coat layer thus formed with LLDPE resin, had a viscosity of 1.2 cc / (m 2It has an oxygen permeability of 100% (24h). Considering that the oxygen permeability of the barrier film in the example depends greatly on the barrier properties of the barrier layer, this is thought to mean that the barrier properties are increased by heating the barrier layer multiple times.

[0086] <Experimental Example 3> Five samples (Samples 1 to 5) were prepared from the barrier film of the experimental example. The tensile strength (N / 15 mm), elongation (%), and tensile modulus (N / mm) in the MD (machine direction) and TD (transverse direction) directions of Samples 1 to 5 were measured. 2 ) and MD of samples 1 to 5 The haze (%) in each direction was measured, and the results are shown in Table 2.

[0087] The tensile strength, elongation and tensile modulus shown in Table 2 are values ​​measured in accordance with JIS K 7161-1:2014 (ISO 527-1:2012). The elongation in Table 2 corresponds to the tensile strain in IS K 7161-1:2014 (ISO 527-1:2012). The haze shown in Table 2 is a value measured in accordance with JIS K 7136:2000 (ISO 14782:1999).

[0088] [Table 2]

[0089] As shown in Table 2, the average tensile strength in the MD direction of samples 1 to 5 was 48.33 (N / 15 mm), the elongation was 900 (%), and the tensile modulus was 335.6 (N / mm 2 ) and haze was 24.69(%).

[0090] The average tensile strength in the TD direction of samples 1 to 5 was 40.26 (N / 15 mm), the elongation was 900 (%), and the tensile modulus was 389.8 (N / mm2 ) was.

[0091] Although the embodiments and experimental examples have been described above, it is also planned from the beginning that the configurations of the above-described embodiments and experimental examples may be appropriately combined.

[0092] The embodiments and experimental examples disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0093] 101 first layer, 102 second layer, 103 third layer, 201 first anchor coat layer, 202 second anchor coat layer, 203 adhesive layer, 301 barrier layer, 401 base, 402 indenter, 403 test piece, 404 arrow, 501 unwinding roll, 502 coating roll, 503 drying oven, 504 extruder, 505 T-die, 506 cooling roll, 507 take-up roll, 601 unwinding roll, 602 coating roll, 603 drying oven, 606 heating roll, 607 unwinding roll, 1000 barrier film, 2000 pouch, 3000 stopper.

Claims

1. a first linear low density polyethylene layer; a second linear low density polyethylene layer; and a barrier layer between the first linear low density polyethylene layer and the second linear low density polyethylene layer, applying a barrier layer precursor onto the first linear low density polyethylene layer; forming the barrier layer by heating the barrier layer precursor; The barrier layer precursor or the barrier layer and the second linear low density polyethylene layer forming a third linear low density polyethylene layer between the first and second linear low density polyethylene layers, The first linear low density polyethylene layer is preferably a second linear low density polyethylene layer. Linear low-density polyethylene is used, which has a higher seal start temperature than A water-soluble resin composition containing a water-soluble resin and inorganic particles is used as the barrier layer precursor. A method for producing a heat-sealable barrier film.

2. a first linear low density polyethylene layer; a second linear low density polyethylene layer; and The first linear low density polyethylene layer and the second linear low density polyethylene layer and a barrier layer between the heat-sealable barrier film, applying a barrier layer precursor onto the first linear low density polyethylene layer; forming the barrier layer by heating the barrier layer precursor; Applying the barrier layer precursor or the adhesive layer precursor onto the barrier layer and then heating forming an adhesion layer on the barrier layer by The adhesive layer is then pressed onto the second linear low density polyethylene layer. forming the second linear low density polyethylene layer bonded to the adhesive layer; the first linear low density polyethylene layer is made of a linear low density polyethylene having a higher seal rise temperature than the second linear low density polyethylene layer; A water-soluble resin composition containing a water-soluble resin and inorganic particles is used as the barrier layer precursor. A method for producing a heat-sealable barrier film.

3. The heat sheet according to claim 2, wherein the adhesive layer is an olefin-based adhesive layer. A method for producing a water-resistant barrier film.

4. The method for producing the heat-sealable barrier film according to any one of claims 1 to 3. producing the heat-sealable barrier film by a method; The second linear low density polyethylene layer of the heat sealable barrier film is sealed. and heat sealing the adhesive layer to form a pouch.

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