Sealant film, laminated film for packaging bags, pouch packaging bag and pouch package

Abstract

To provide a sealant film and a laminated film for packaging bags that can reduce an environmental load and can obtain a pouch packaging bag with excellent drop resistance and pouch stiffness, and a pouch packaging bag and a pouch package with excellent drop resistance and pouch stiffness.SOLUTION: A sealant film of the present invention has a sealing layer made of a polyethylene resin composition containing a low-density polyethylene and a linear low-density polyethylene. The low-density polyethylene is made of a polymer of ethylene derived from a plant, and the melt flow rate of the low-density polyethylene is 7 g / 10 min or less.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a sealant film using a plant-derived synthetic resin material, a laminate film for packaging bags provided with this sealant film, and a pouch packaging bag and a pouch package using this laminate film for packaging bags. [Background technology]

[0002] For example, pouch packaging bags such as standing pouches made of a laminated film in which a sealant film is laminated on a base film are used as containers for refilling detergent, shampoo, etc. Such pouch packaging bags are required to have excellent drop resistance so that the film is not damaged by impact when dropped, and high pouch rigidity that contributes to ease of holding the pouch packaging bag, ease of pouring contents when refilling, and self-supporting ability of the pouch packaging bag. Since 75% or more of the thickness of the laminated film is accounted for by the thickness of the sealant film, the pouch rigidity of the refill pouch packaging bag is greatly affected by the rigidity of the sealant film. Furthermore, in the case of pouch packaging bags, there is a demand for thinner films in response to the demand for reducing the amount of plastic used, while at the same time there is a demand for larger capacities so that the contents can be filled with 800 g or more so that the pouch can be refilled two or more times.

[0003] In recent years, with regard to synthetic resin materials, there has been a demand for a shift from fossil fuel-derived materials to plant-derived materials in response to demands for reducing the environmental burden caused by the creation of a recycling-based society. Conventionally, sealant films that make up pouch packaging bags are known to be made of linear low-density polyethylene, low-density polyethylene, or a mixture of these from the standpoint of heat sealability, impact resistance, etc., and resin films using plant-derived materials have been proposed that use plant-derived linear low-density polyethylene or low-density polyethylene (see Patent Documents 1 and 2). However, when such a sealant film is used to form a pouch packaging bag, it has been found that it is difficult to obtain the required drop resistance or pouch rigidity when attempting to increase the capacity or reduce the thickness of the film. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6197820 [Patent Document 2] JP 2017-114495 A Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made in light of the above circumstances, and an object of the present invention is to provide a sealant film and a laminate film for packaging bags that can reduce the environmental impact and produce pouch packaging bags that are excellent in drop resistance and pouch rigidity. Another object of the present invention is to provide a pouch packaging bag and a pouch package which can reduce the environmental load and have excellent drop resistance and pouch rigidity. [Means for solving the problem]

[0006] The sealant film of the present invention is a sealant film having a seal layer made of a polyethylene resin composition containing a low-density polyethylene and a linear low-density polyethylene, The low-density polyethylene is made of a polymer of ethylene derived from plants, and has a melt flow rate of 0.6 to 3.8 g / 10 min and a density of 0.916 to 0.928 g / cm. 3 The linear low density polyethylene has a melt flow rate of 0.8 to 1.0 g / 10 min and a density of 0.910 to 0.929 g / cm 3 and The content of the low-density polyethylene in the polyethylene resin composition is 1 to 29% by mass, The polyethylene resin composition has a melt flow rate of 0.8 to 1.0 g / 10 min and a density of 0.910 to 0.929 g / cm 3 The content of the linear low-density polyethylene is 70% by mass or more, The melt flow rate is 0.8 to 1.0 g / 10 min and the density is 0.910 to 0.929 g / cm 3 The linear low-density polyethylene is composed only of a copolymer of ethylene and an α-olefin having 6 to 10 carbon atoms, The sealant film is characterized in that it has an impact value of 1.4 J or more and a stiffness value of 40 mN or more.

[0010] In the sealant film of the present invention, the sealing layer preferably has a thickness of 70 to 190 μm.

[0011] The laminated film for packaging bags of the present invention is characterized by having the above sealant film and a base film.

[0012] The laminated film for packaging bags of the present invention preferably has a thickness of 110 to 240 μm.

[0013] The pouch packaging bag of the present invention is characterized in that it is formed from the above-mentioned laminate film for packaging bags.

[0014] The pouch package of the present invention is characterized in that the above-mentioned pouch package bag is filled with contents. Effect of the Invention

[0015] The sealant film of the present invention contains a specific low-density polyethylene obtained by polymerization of plant-derived ethylene and a linear low-density polyethylene, and therefore has high impact resistance and high rigidity. Therefore, by forming a pouch packaging bag using the sealant film of the present invention, it is possible to reduce the environmental load, and further, a pouch packaging bag and a pouch package having excellent drop resistance and pouch rigidity can be obtained. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an embodiment of the present invention will be described in detail. [Sealant film] The sealant film of the present invention has a seal layer made of a polyethylene resin composition containing a specific low-density polyethylene and a linear low-density polyethylene.

[0017] In the polyethylene resin composition constituting the seal layer, the specific low-density polyethylene is made of a polymer of plant-derived ethylene. This polymer is obtained, for example, by radical polymerization of plant-derived ethylene under high pressure using a radical polymerization initiator. The ethylene for obtaining the specific low-density polyethylene may be entirely plant-derived, or may be partially fossil fuel-derived. The specific low-density polyethylene may also be a copolymer obtained by copolymerizing ethylene with a small amount of other monomer.

[0018] The specific low-density polyethylene has a melt flow rate (MFR) of 7.0 g / 10 min or less, preferably 0.3 to 7.0 g / 10 min, more preferably 0.6 to 3.8 g / 10 min, measured in accordance with JIS K7210 (temperature 190°C, load 2.16 kg). When a low-density polyethylene having a melt flow rate (MFR) of more than 7.0 g / 10 min is used, the sealant film has low rigidity, and it is therefore difficult to obtain a pouch packaging bag having high pouch rigidity. When the melt flow rate (MFR) of the specific low-density polyethylene is less than 0.3 g / 10 min, it may be difficult to uniformly knead the specific low-density polyethylene and the linear low-density polyethylene.

[0019] The specific low density polyethylene has a density of 0.916 to 0.928 g / cm 3 It is preferable to use one in which

[0020] In the polyethylene resin composition constituting the seal layer, the content of the specific low-density polyethylene is 1 to 29% by mass, preferably 5 to 27% by mass, and more preferably 10 to 25% by mass. When the content of the specific low-density polyethylene is less than 1% by mass, the sealant film has low rigidity, and therefore it may be difficult to obtain a pouch packaging bag having high pouch rigidity. On the other hand, when the content of the specific low-density polyethylene is more than 29% by mass, the sealant film has low impact resistance, and therefore it may be difficult to obtain a pouch packaging bag having high drop resistance.

[0021] In the polyethylene resin composition constituting the sealing layer, the linear low-density polyethylene is preferably a copolymer of ethylene and an α-olefin having a carbon number of 6 to 10. As the α-olefin having a carbon number of 6 to 10, 1-hexene and 1-octene are preferred, and these can be used alone or in combination. When a linear low-density polyethylene in which the α-olefin has 5 or less carbon atoms, for example, the α-olefin is 1-butene (having 4 carbon atoms), is used, the sealant film has low impact resistance, and therefore, it may be difficult to obtain a pouch packaging bag with high drop resistance. Furthermore, the ethylene used to obtain the linear low density polyethylene may be derived from either fossil fuels or plants.

[0022] Linear low-density polyethylene has a density of 0.910 to 0.929 g / cm 3 , preferably 0.915 to 0.926 g / cm 3 The density of linear low-density polyethylene is 0.910 g / cm 3 If the density of the linear low-density polyethylene is less than 0.929 g / cm, the sealant film will have low rigidity, and it may be difficult to obtain a pouch packaging bag having high pouch rigidity. 3If it exceeds this value, the sealant film will have low impact resistance, and therefore it may be difficult to obtain a pouch packaging bag having high drop resistance.

[0023] The linear low-density polyethylene preferably has a melt flow rate (MFR) of 2.5 g / 10 min or less, more preferably 0.8 to 2.2 g / 10 min, measured in accordance with JIS K7210 (temperature 190°C, load 2.16 kg). If the melt flow rate of the linear low-density polyethylene exceeds 2.5 g / 10 min, the sealant film will have low impact resistance, and therefore it may be difficult to obtain a pouch packaging bag with high drop resistance.

[0024] As the linear low-density polyethylene, a copolymer polymerized with a single-site catalyst such as a metallocene catalyst or a multi-site catalyst such as a Ziegler catalyst can be used. However, it is preferable to use a copolymer polymerized with a single-site catalyst because it has a narrow molecular weight distribution and a small amount of low molecular weight components.

[0025] In the polyethylene resin composition constituting the seal layer, the content of linear low-density polyethylene is preferably 70% by mass or more, more preferably 75% by mass or more. If the content of linear low-density polyethylene is less than 70% by mass, the sealant film tends to have low impact resistance, and therefore it may be difficult to obtain a pouch packaging bag having high drop resistance.

[0026] The polyethylene resin composition constituting the sealing layer may contain resins other than the specific low density polyethylene and linear low density polyethylene, provided that the object of the present invention is not impaired. The polyethylene resin composition constituting the sealing layer may contain various additives such as a lubricant, an antioxidant, and an antiblocking agent.

[0027] In the sealant film of the present invention, the thickness of the seal layer is preferably 70 to 190 μm, more preferably 100 to 170 μm, and particularly preferably 110 to 150 μm. If the thickness of the seal layer is less than 70 μm, it is difficult to impart pouch rigidity when forming a standing pouch (a pouch made by laminating a 15 μm biaxially oriented nylon film and a sealant film) that is currently widely available on the market. On the other hand, if the thickness of the seal layer exceeds 190 μm, it is satisfactory in terms of performance such as drop resistance and pouch rigidity, but is not preferable in terms of the environment such as efficient resource utilization and the economy such as cost-effectiveness.

[0028] The sealant film of the present invention may be a single-layer structure consisting of the above-mentioned seal layer alone, or may be a laminate structure consisting of the above-mentioned seal layer and another resin layer. Examples of materials constituting the other resin layer include linear low-density polyethylene, low-density polyethylene, medium-density polyethylene, high-density polyethylene, and mixtures thereof.

[0029] [Laminated film for packaging bags] The laminated film for packaging bags of the present invention comprises the above sealant film and a base film. The base film is not particularly limited, and may be any film that is normally used for pouch packaging bags. Specific examples of the substrate film include polyolefins such as crystalline polypropylene, crystalline propylene-ethylene copolymer, crystalline polybutene-1, crystalline poly4-methylpentene-1, low-density polyethylene, medium-density polyethylene, high-density polyethylene, ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate copolymer (EEA), and ionically crosslinked olefin copolymers (ionomers); aromatic vinyl copolymers such as polystyrene and styrene-butadiene copolymer; halogenated vinyl polymers such as polyvinyl chloride and vinylidene chloride resin; nitrile polymers such as acrylonitrile-styrene copolymer and acrylonitrile-styrene-butadiene copolymer; polyamides such as nylon 6, nylon 66, and para- or meta-xylylene adipamide; polyesters such as polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), and polybutylene terephthalate (PBT); various polycarbonates; and polyacetals such as polyoxymethylene. Furthermore, when the contents to be filled are sensitive to oxygen, the base film may be a film in which a metal oxide or the like is vapor-deposited onto the above-mentioned resin film, or a film coated with an organic compound, or a film provided with a layer made of an ethylene-vinyl alcohol copolymer (EVOH) resin. Films made of these materials may be used in an unstretched, uniaxially stretched, or biaxially stretched state.

[0030] As the base film, the above-mentioned resin films can be used as a single layer or a laminate of two or more types. Also, a laminate of one or more types of these resin films with a metal foil such as aluminum, paper, cellophane, etc. can be used. Preferred examples of the substrate film include a single-layer film made of a stretched nylon film or a stretched polyester film, a two-layer film made by laminating a polyolefin film such as low-density polyethylene or polypropylene with PET, and a three-layer film made by laminating PET / nylon / polyethylene. More preferably, an environmentally friendly material is used as the material constituting the base film. The environmentally friendly material is, for example, a resin (e.g., PET, nylon 6) that uses a monomer obtained from a raw material derived from plant and thus has the same functionality as a resin derived from fossil fuels while being environmentally friendly by being carbon neutral, a resin using a monomer obtained from a raw material derived from plant (e.g., polylactic acid, polybutylene succinate (PBS), polyethylene furanoate (PEF)), or a resin obtained by recycling a resin using a monomer derived from fossil fuels. The resin obtained by recycling may include a resin using a monomer obtained from a raw material derived from plant. In producing the laminated film, an adhesive or an anchoring agent may be interposed between the layers as required. The base film may also be provided with an ink layer that expresses a design.

[0031] The thickness of the base film can be appropriately set depending on the material of the base film and the shape and dimensions of the pouch packaging bag to be formed, but is usually selected from the range of 3 to 50 μm, preferably 5 to 40 μm.

[0032] The method for laminating the base film to the sealant film is not particularly limited, and examples thereof include a method in which the base film is directly laminated to the sealant film by extrusion lamination, etc., and a method in which the base film is laminated to the sealant film via an adhesive by dry lamination, etc. Examples of the adhesive that can be used in dry lamination include urethane-based adhesives, acid-modified polyolefin-based adhesives, polyester-based adhesives, polyether-based adhesives, polyamide-based adhesives, etc.

[0033] The overall thickness of the packaging bag laminate film is preferably 110 to 240 μm, more preferably 120 to 210 μm, and particularly preferably 130 to 190 μm.

[0034] [Pouch packaging bag] The pouch packaging bag of the present invention is constituted by the above-mentioned laminated film for packaging bags. The specific form of the pouch packaging bag is not particularly limited, but it is suitable as a pouch packaging bag that requires high pouch rigidity, such as a standing pouch. The standing pouch referred to here is a known standing pouch, which is made by heat-sealing two body materials, a front and a back, made of laminated film, and a base material folded into an inverted V shape with side seals and bottom seals.

[0035] [Pouch packaging] The pouch package of the present invention is obtained by filling the above-mentioned pouch packaging bag with a content. The content filled in the pouch packaging bag is not particularly limited, and may be, for example, a liquid or gel content containing a surfactant. Specific examples of the content containing a surfactant include shampoo, body shampoo, hair rinse, hair treatment, liquid laundry detergent, liquid bleach, fabric softener, liquid kitchen detergent, etc.

[0036] The surfactant contained in the contents is one or more selected from anionic surfactants, nonionic surfactants, cationic surfactants, and amphoteric surfactants. Examples of such surfactants include fatty acid salts, alphasulfo fatty acid ester salts, alkylbenzene sulfonates, alkyl sulfates, alkyl ether sulfates, and polyoxyalkylene surfactants.

[0037] According to the present invention, since the sealant film contains a specific low-density polyethylene obtained by polymerization of plant-derived ethylene and a linear low-density polyethylene, high impact resistance and high rigidity are obtained. Therefore, when a pouch packaging bag is formed, it is possible to reduce the environmental load, and a pouch packaging bag and a pouch package having excellent drop resistance and pouch rigidity can be obtained. EXAMPLES

[0038] The present invention will be described below with reference to specific examples, but the present invention is not limited to these examples. In addition, the specific low density polyethylenes (LDPE (1) and LDPE (2)), other low density polyethylenes (LDPE (3) and LDPE (4)), and linear low density polyethylenes (LLDPE (5) and LLDPE (6)) used in the following examples and comparative examples have the properties shown in Table 1 below.

[0039] [Table 1]

[0040] Example 1 25% by mass of LDPE (1) and 75% by mass of LLDPE (5) were mixed, and the resulting mixture was fed to a single-screw extruder, melt-kneaded, and extruded from a T-die film molding device connected to the single-screw extruder. The extruded molten resin was then cast onto a cooling roll and cooled to produce a sealant film consisting of only a sealing layer having a thickness of 110 μm. In the above, the temperature of the cylinder of the single screw extruder is 200°C, the temperature of the T-die head is 210°C, and the temperature of the cooling roll is 60°C. The resin temperature was measured at the joint between the single screw extruder and the T-die and was found to be 204 to 210°C.

[0041] Example 2 25% by mass of LDPE (2) and 75% by mass of LLDPE (5) were mixed, and the resulting mixture was extrusion-molded in the same manner as in Example 1 to produce a sealant film consisting only of a sealing layer with a thickness of 110 μm.

[0042] Example 3 25% by mass of LDPE (3) and 75% by mass of LLDPE (5) were mixed, and the resulting mixture was extrusion-molded in the same manner as in Example 1 to produce a sealant film consisting only of a sealing layer with a thickness of 110 μm.

[0043] Comparative Example 1 LLDPE (5) was extruded in the same manner as in Example 1 to produce a sealant film consisting only of a sealing layer having a thickness of 110 μm.

[0044] Comparative Example 2 LLDPE (6) was extruded in the same manner as in Example 1 to produce a sealant film consisting only of a sealing layer having a thickness of 110 μm.

[0045] Comparative Example 3 25% by mass of LDPE (4) and 75% by mass of LLDPE (5) were mixed, and the resulting mixture was extrusion-molded in the same manner as in Example 1 to produce a sealant film consisting only of a sealing layer with a thickness of 110 μm.

[0046] [Evaluation of sealant film] The impact value and stiffness value of the sealant films obtained in Examples 1 to 3 and Comparative Examples 1 to 3 were measured by the following method, and the drop resistance and pouch stiffness of the pouch packaging bag made using each sealant film were evaluated according to the following criteria. The results are shown in Table 2 below.

[0047] Impact Value: Each sealant film was cut into a size of 100 mm x 100 mm to prepare a test specimen. The test specimen was left to stand in a constant temperature room at 5°C for one day before measurement. The energy required to break the test specimen was then measured using a film impact tester (manufactured by Toyo Seiki) installed in a constant temperature room at 5°C. The impact head sphere and capacity of the film impact tester were 1 / 2 inch x 30 kg cm. Stiffness value: For each sealant film, the stiffness value was measured using a loop stiffness tester (manufactured by Toyo Seiki Seisakusho) under the following measurement conditions. (Measurement conditions) Sample dimensions: Loop length = 100 mm, width = 30 mm Push-in distance: 0mm

[0048] Drop resistance rating criteria: The sealant films with an impact value of 1.4 J or more were rated as ◯, and the sealant films with an impact value of less than 1.4 J were rated as ×. Pouch stiffness evaluation criteria: The sealant films having a stiffness value of 40 mN or more were rated as ◯, and the sealant films having a stiffness value of less than 40 mN were rated as ×.

[0049] [Table 2]

[0050] As is clear from the results in Table 2, the sealant films of Examples 1 to 3 show high values ​​for both impact value and stiffness value, which indicates that it is possible to construct a pouch packaging bag having excellent drop resistance and pouch rigidity. In contrast, the sealant films according to Comparative Examples 1 and 2 use only linear low-density polyethylene and do not use any specific low-density polyethylene, and either the impact value or the stiffness value shows a low value, making it difficult to configure a pouch packaging bag having both excellent drop resistance and pouch stiffness. Also, the sealant film according to Comparative Example 3 uses low-density polyethylene with a high MFR and shows a low stiffness value, making it difficult to configure a pouch packaging bag having high pouch stiffness.

Claims

1. A sealant film having a seal layer made of a polyethylene resin composition containing a low-density polyethylene and a linear low-density polyethylene, The low-density polyethylene is made of a polymer of ethylene derived from plants, and has a melt flow rate of 0.6 to 3.8 g / 10 min and a density of 0.916 to 0.928 g / cm. ３ The linear low density polyethylene has a melt flow rate of 0.8 to 1.0 g / 10 min and a density of 0.910 to 0.929 g / cm ３ and The content of the low-density polyethylene in the polyethylene resin composition is 1 to 29 mass%; the content of the linear low-density polyethylene having a melt flow rate of 0.8 to 1.0 g / 10 min and a density of 0.910 to 0.929 g / cm 3 in the polyethylene resin composition is 70 mass % or more; the linear low-density polyethylene having a melt flow rate of 0.8 to 1.0 g / 10 min and a density of 0.910 to 0.929 g / cm 3 is composed only of a copolymer of ethylene and an α-olefin having 6 to 10 carbon atoms; A sealant film, characterized in that the sealant film has an impact value of 1.4 J or more and a stiffness value of 40 mN or more.

2. A sealant film as described in claim 1, characterized in that the thickness of the sealing layer is 70 to 190 μm.

3. A laminated film for packaging bags, characterized in having a sealant film as described in claim 1 or claim 2 and a base film.

4. A laminated film for packaging bags as described in claim 3, characterized in that the thickness is 110 to 240 μm.

5. A pouch packaging bag characterized by being made of a laminated film for packaging bags as described in claim 3 or claim 4.

6. A pouch packaging body, characterized in that the contents are filled into the pouch packaging bag described in claim 5.

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