Laminated film for packaging materials and packaging bags
A laminated film using plant-derived low-density polyethylene resin and polyester for packaging materials addresses durability and processability issues of petroleum-based alternatives, reducing resource use and emissions while maintaining performance.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- DAI NIPPON PRINTING CO LTD
- Filing Date
- 2024-10-30
- Publication Date
- 2026-06-23
Smart Images
Figure 0007878378000001 
Figure 0007878378000002 
Figure 0007878378000003
Abstract
Description
[Technical Field]
[0001] This disclosure relates to laminated films for packaging materials and packaging bags, and more particularly to laminated films for packaging materials in which films made of a resin composition containing a plant-derived low-density polyethylene resin are laminated, and to packaging bags using the same film. [Background technology]
[0002] For example, flexible packaging (light packaging), widely used as packaging for frozen foods such as dumplings, fried shumai, fried rice, and pizza, is composed of flexible packaging materials consisting of a sealant film and a base film. However, many of the raw materials for flexible packaging materials are petroleum-derived, and there is a need to address environmental issues and conserve depleting resources such as petroleum. To reduce the amount of petroleum resources used in packaging materials, a biodegradable resin composition is known that contains predetermined amounts of ethylene-α-olefin copolymer and epoxy group polymer in a polylactic acid resin, which is a carbon-neutral material. This composition is described in a packaging bag (for example, Patent Document 1). [Prior art documents] [Patent Documents]
[0003] [Patent Document 1] Japanese Patent Publication No. 2009-155516 [Overview of the project] [Problems that the invention aims to solve]
[0004] The proportion of petroleum-derived raw materials can be reduced by incorporating biodegradable resins other than petroleum-derived raw materials into the resin composition that makes up the packaging bag. However, such packaging bags are significantly inferior to those made of petroleum-based resins in terms of tensile strength, tear strength, seal strength, stiffness, and other processability, making it difficult to improve productivity and durability.
[0005] Therefore, the object of the present invention is to provide an environmentally friendly laminated film for packaging materials that conserves petroleum resources and reduces carbon dioxide emissions, and a packaging bag using this film that has processing suitability, physical properties, and especially durability comparable to petroleum resin packaging bags. [Means for solving the problem]
[0006] To solve the above problems, the present invention provides a laminated film for packaging materials, comprising a sealant film made of a resin composition containing a plant-derived low-density polyethylene resin obtained by polymerizing plant-derived ethylene by a high-pressure method, and a base film having a printed pattern, wherein the base film is a polyester resin film, the base film having the printed pattern and the sealant film are laminated via a laminating adhesive, the laminated film for packaging materials has a biomass content of at least 25% as calculated from radiocarbon dating 14C measurements, and the sealant film is characterized in that it does not contain 0.2% by mass or more of silica, 5.0% by mass or more of titanium dioxide, ionomers, and ethylene-methacrylic acid copolymer. Furthermore, the plant-derived low-density polyethylene resin is characterized by having a biomass content of 10-100%. Furthermore, the base film is characterized by being a film made of a resin composition containing a plant-derived polyethylene terephthalate resin obtained by condensation polymerization of plant-derived ethylene glycol and petroleum-derived terephthalic acid. Furthermore, the sealant film contains 10 to 10 of the plant-derived low-density polyethylene resin. The resin composition, comprising 100% by weight of a petroleum-derived low-density polyethylene resin and 0 to 90% by weight of a petroleum-derived low-density polyethylene resin, is characterized by being composed of either (A) or (B) below. (A) Single layer structure consisting of the resin composition (B) A multilayer structure in which the middle layer is made of the resin composition, and the outer and inner layers are made of the petroleum-derived low-density polyethylene resin. Furthermore, the packaging bag of the present invention is characterized by being made using the above-mentioned laminated film for packaging materials.
Advantages of the Invention
[0007] According to the present invention, there is provided a laminated film for packaging materials, which is obtained by laminating a sealant film made of a resin composition containing a plant-derived low-density polyethylene resin obtained by polymerizing plant-derived ethylene by a high-pressure method and a base film. The laminated film for packaging materials has a biomass degree calculated from the measured value of radiocarbon dating 14 C of at least 25%. Therefore, the amount of petroleum resources, which are widely used as raw materials for the sealant film constituting the laminated film for packaging materials, can be reduced, and the carbon dioxide emissions derived from petroleum during film production and disposal can be suppressed. Furthermore, since it is not inferior in physical properties to petroleum-derived low-density polyethylene resin, it can be made the same as the manufacturing process of existing laminated films for packaging materials, and the raw materials can be switched without impairing the processing suitability of the packaging material. Furthermore, the origin of the raw material of the low-density polyethylene resin constituting the laminated film for packaging materials can be identified using this biomass degree as an index, and the origin of the raw material can be confirmed from the time of film production to the time of disposal. Therefore, it is possible to provide a laminated film for packaging materials containing a low-density polyethylene-based resin with a reduced environmental load, excellent production efficiency, and the ability to identify the origin of the raw material.
[0008] Furthermore, according to the configuration in which the plant-derived low-density polyethylene resin has a biomass degree of 10 to 100%, the usage ratio of petroleum-derived raw materials of the low-density polyethylene resin constituting the sealant film can be further reduced, the amount of petroleum resources used can be further reduced, and the carbon dioxide emissions derived from petroleum during film production and disposal can be further suppressed.
[0009] Furthermore, according to the configuration in which the base film is a film made of a resin composition containing a plant-derived polyethylene terephthalate resin obtained by condensation polymerization of plant-derived ethylene glycol and petroleum-derived terephthalic acid, even in the base film, the usage ratio of petroleum-derived raw materials can be reduced, the amount of petroleum resources used can be further reduced, and the amount of petroleum-derived carbon dioxide emissions during the production and disposal of the laminated film for packaging materials can be further suppressed. And the laminated film for packaging materials has a tensile strength, a seal strength, and a stiffness suitable for a packaging bag, for example, a flexible packaging bag, and exhibits excellent processing suitability.
[0010] Furthermore, the sealant film uses a resin composition containing 10 to 100 mol% of a plant-derived low-density polyethylene resin and 0 to 90 mol% of a petroleum-derived low-density polyethylene resin, and the following (A) and (B) (A) A single-layer structure in which the resin composition and a petroleum-derived low-density polyethylene resin are mixed (B) A multilayer structure in which the middle layer is a layer in which the resin composition and a petroleum-derived low-density polyethylene resin are mixed, and the outer layer and the inner layer are made of a petroleum-derived low-density polyethylene resin According to the configuration which is either of the above, the usage ratio of the petroleum-derived low-density polyethylene resin constituting the laminated film for packaging materials can be reduced, the amount of petroleum resources used can be reduced, and the amount of petroleum-derived carbon dioxide emissions during film production and disposal can be suppressed. In addition, by using a petroleum-derived low-density polyethylene resin for the inner and outer layers constituting the sealant film as in (B), the film can be produced with the characteristics of the existing manufacturing process. Therefore, a laminated film for packaging materials having more excellent processing suitability can be provided.
[0011] Furthermore, according to the configuration in which an intermediate layer is further provided between the sealant film and the base film, the laminated film for packaging materials can be configured to have various functions, for example, gas barrier properties.
[0012] Furthermore, since the packaging bag of the present invention is made using the laminated film for packaging materials described above, the proportion of petroleum-derived low-density polyethylene resin used in the laminated film for packaging materials constituting the packaging bag can be reduced, thereby reducing the amount of petroleum resources used and suppressing petroleum-derived carbon dioxide emissions during the manufacturing and disposal of the packaging bag. Moreover, the proportion of petroleum-derived raw materials used in packaging bags, which are widely distributed as disposable items, can be reduced. Furthermore, as described above, the processability and physical properties of the laminated film for packaging materials are comparable to those of petroleum-derived materials. Therefore, it is possible to provide a packaging bag that contains plant-derived low-density polyethylene resin, which conserves petroleum resources and reduces environmental impact, while possessing processability, physical properties, and especially durability, comparable to those of petroleum-based resins. [Brief explanation of the drawing]
[0013] [Figure 1] This flowchart illustrates the manufacturing process of low-density polyethylene film derived from sugarcane. [Figure 2] This is a schematic cross-sectional view of a sealant film containing a sugarcane-derived low-density polyethylene resin according to this embodiment. [Figure 3] This is a schematic cross-sectional view showing a film consisting of a multilayer structure in which the middle layer is made of bio-low-density polyethylene resin. [Figure 4] This is a schematic cross-sectional view showing an example of a laminated film for packaging materials according to this embodiment. [Figure 5] This flowchart illustrates the manufacturing process of plant-derived polyethylene terephthalate film. [Figure 6] This is a schematic cross-sectional view showing an example of a packaging bag made by heat-sealing a laminated film for packaging materials. [Figure 7] This is a perspective view showing a four-sided sealed bag, which is an example of a packaging bag formed using the laminated film for packaging materials according to this embodiment. [Modes for carrying out the invention]
[0014] Embodiments of the present invention will be described in detail below with reference to the drawings.
[0015] Flexible packaging, widely used for food and daily necessities, is constructed from laminated film. Some laminated films have a sealant film (heat-sealable film) laminated onto a base film, serving as a heat-sealing material for the inner surface of the flexible packaging. For example, polyester resins are used for the base film. On the other hand, low-density polyethylene (LDPE: Low Density PolyEthylene (PE-LD)) resin is used for the sealant film. Low-density polyethylene resin is inexpensive and offers excellent flexibility, transparency, extrusion coating properties, and heat adhesion.
[0016] As described above, low-density polyethylene resins and polyester resins are frequently used as materials for laminated films. These low-density polyethylene resins and polyester resins are manufactured using petroleum as a starting material. For example, low-density polyethylene is produced by addition polymerization of ethylene (ethene), obtained through crude oil refining, under high temperature and high pressure conditions such as 300°C and 2000 atmospheres.
[0017] On the other hand, awareness of environmental issues such as the depletion of resources like oil and global warming caused by increased carbon dioxide emissions is growing year by year. In this context, low-density polyethylene derived from petroleum is becoming increasingly important. The use of ethylene resins and similar materials means that large amounts of carbon dioxide, which was fixed in petroleum, are released into the atmosphere during the entire process from the manufacture to the disposal of petrochemical products, thus demonstrating a lack of consideration for the environment.
[0018] Against this backdrop, development of technologies to manufacture plastics from plants, which are carbon-neutral and renewable resources, has progressed, and a technology has been established to produce polyethylene, the most widely used plastic, using biomass-based sugarcane as a starting material (Processing Technology Research Group, Convertech 2009.9, pp. 63-67). Carbon neutrality means that the amount of carbon dioxide absorbed during plant growth is approximately the same as the amount of carbon dioxide emitted during combustion or decomposition, that is, it is neutral with respect to the amount of carbon cycling in the environment.
[0019] Next, the manufacturing process of the sealant film constituting the laminated film for packaging materials according to this embodiment will be described. Figure 1 is a flowchart illustrating the manufacturing process of a low-density polyethylene film derived from sugarcane, and Figure 2 is a schematic cross-sectional view showing a sealant film containing low-density polyethylene resin derived from sugarcane according to this embodiment. In this embodiment, sugarcane is used as the starting material for the laminated film for packaging materials and the packaging bag. However, the raw materials for the laminated film for packaging materials and the packaging bag according to this embodiment are not limited to sugarcane, but may be any plant that can be used as a raw material for the production of low-density polyethylene resin, and furthermore, any renewable, biologically derived organic resource excluding fossil resources may be used.
[0020] As shown in Figure 1, first, the sugar syrup extracted from sugarcane harvested from the field is heated and concentrated, and the mixture of crystallized raw sugar and the amorphous sugarcane molasses 1 is separated using a centrifuge. This sugarcane molasses 1, a by-product of sugar production, is used as the raw material.
[0021] Bioethanol 2 is produced by diluting sugarcane molasses 1 to an appropriate concentration with water, fermenting it with yeast, and then distilling it (Step S101).
[0022] Bioethanol 2 is heated in the presence of a catalyst, and bioethylene 3, which is derived from plants, is obtained by an intramolecular dehydration reaction (Step S102).
[0023] Bioethylene 3 (monomer) is polymerized by a high-pressure method to obtain a plant-derived bio-low-density polyethylene resin 10 (Step S103).
[0024] As described above, the bio-low-density polyethylene resin 10 used in the sealant film constituting the laminated film for packaging materials according to this embodiment is produced from ethylene derived from plants such as sugarcane as a starting material. Furthermore, it has been confirmed that plant-derived ethylene and polyethylene are of equivalent quality to petroleum-derived ethylene and polyethylene. Therefore, the bio-low-density polyethylene resin 10 can be manufactured in the same way as when low-density polyethylene resin is produced from petroleum-derived ethylene. That is, the bio-low-density polyethylene resin 10 can be produced by addition polymerization of bioethylene 3 under high temperature and high pressure conditions such as 300°C and 2000 atmospheres.
[0025] Bio-low-density polyethylene resin 10, like petroleum-derived low-density polyethylene resin, has a density d of 0.910-0.925 g / cm³. 3 , melt flow rate (MFR) is 0.5~ It can have physical properties ranging from 8.0 g / 10 min, more preferably in the range of 0.7 to 5.0 g / 10 min.
[0026] Note that density (d, unit: g / cm³) 3 ) is a material obtained by press molding at 150°C with a thickness of 1 A mm sheet was used, and measurements were taken in accordance with JIS K 6760 (1981). Furthermore, the melt flow rate (MFR, unit: g / 10 min) was measured in accordance with JIS K 7210 (1995), under conditions of a test temperature of 190°C and a test load of 21.18 N. The melt flow rate value is the amount (g) extruded in 10 minutes when a cylinder with a 2 mm diameter hole at the bottom was heated to 190°C and a load of 21.18 N was applied to the sample placed inside the cylinder. As the degree of polymerization of the polymer increases, the viscosity at melt increases, and therefore the melt flow rate tends to decrease.
[0027] A sealant film constituting a laminated film for packaging materials is manufactured using a bio-low-density polyethylene resin 10 having these physical properties. In this process, a petroleum-derived low-density polyethylene resin 11 is mixed in as needed. The petroleum-derived low-density polyethylene resin 11 is mixed in such an appropriate proportion of 10 to 100% by mass that the bio-low-density polyethylene resin 10 is contained within it.
[0028] A resin composition containing bio-low-density polyethylene resin 10 in an appropriate proportion of 10 to 100 mol% is mixed with petroleum-derived low-density polyethylene resin 11. By forming a film, a film F1 containing bio-low-density polyethylene is formed as shown in Figure 2 (Step S104).
[0029] While there are no particular limitations on the method for manufacturing the sealant film constituting the laminated film for packaging materials according to this embodiment, melt extrusion molding is preferably used, and methods such as the inflation method and the flat die method are suitably employed. Furthermore, the sealant film may be processed into a multilayer structure with multiple layers stacked on top of each other, in which case the co-extrusion method is suitably employed.
[0030] In this embodiment, a sealant film that constitutes a laminated film for packaging materials is manufactured using the bio-low density polyethylene resin 10 derived from plants obtained as described above. As a result, this embodiment reduces the usage ratio of petroleum-derived resins in the resin composition used for the laminated film for packaging materials, reduces the consumption of petroleum, which is a fossil resource (depletable resource), and contributes to preventing global warming by reducing the amount of carbon dioxide emissions.
[0031] And in this embodiment, radiocarbon dating 14 The bio-low density polyethylene resin 10 having a biomass degree of 80 to 100% by ¹⁴C is used.
[0032] Here, it is difficult to distinguish between a resin derived from plants (biomass) and a resin derived from petroleum based on physical properties such as molecular weight, mechanical properties, and thermal properties. Therefore, biomass degree is used as a general index for identifying the content ratio of the resin derived from plants in the resin composition. This biomass degree utilizes the fact that the carbon of petroleum-derived resins does not contain (remain) ¹⁴C (radiocarbon 14, half-life 5730 years), and this ¹⁴C concentration is calculated by being measured by accelerator mass spectrometry. Therefore, by measuring the biomass degree of the film, it is possible to identify whether a plant-derived raw material has been used and the content ratio of the plant-derived resin in the resin composition. 14 ¹⁴C (radiocarbon 14, half-life 5730 years) is not contained (remains), and this 14 ¹⁴C concentration is calculated by being measured by accelerator mass spectrometry. Therefore, by measuring the biomass degree of the film, it is possible to identify whether a plant-derived raw material has been used and the content ratio of the plant-derived resin in the resin composition.
[0033] In the first step of measuring this biomass degree, carbon dioxide generated by burning the measurement target sample and purified in a vacuum line is reduced with hydrogen using iron as a catalyst to generate graphite. And this graphite is mounted on a dedicated device for ¹⁴C-AMS (Accelerator Mass Spectrometry) based on a tandem accelerator ( 14 manufactured by NEC Corporation), and by this, the counting of ¹⁴C and also the concentration of ¹⁴C ( 14 ¹⁴C), and the concentration of 13 ¹⁴C ( 13 ¹⁴C / 12C), and 14 C's flux ( 14 C / 12 Measurement C) is performed. From these measurements, the sample carbon relative to standard modern carbon is 14 The percentage of C concentration is calculated. Note that in this measurement, 14 Standards for C measurement The quantitative analysis is performed using oxalic acid (HOx II), provided as a sample by the National Institute of Standards and Technology (NIST).
[0034] In this embodiment, a sealant film having such a biomass content is used. Furthermore, instead of being entirely made of petroleum-derived resin, in this embodiment, a bio-low-density polyethylene resin 10, which is comparable in physical properties to that of petroleum-derived resin, is mixed (substituted) with the petroleum-derived low-density polyethylene resin 11. As a result, in this embodiment, petroleum-derived carbon dioxide emissions during the manufacture and disposal of the sealant film can be reduced.
[0035] Furthermore, in this embodiment, the bio-low-density polyethylene resin 10 contained in the resin composition has a density d of 0.910 to 0.925 g / cm³. 3 , melt flow rate is 0.5~8.0 Low-density polyethylene derived from plants is used (g / 10 min). This makes it possible to manufacture plant-derived sealant films with physical properties comparable to those derived from petroleum, using existing film manufacturing processes. Therefore, raw materials can be switched without compromising the processability of the packaging material. Furthermore, the plant-derived sealant film according to this embodiment is also comparable to that derived from petroleum in terms of durability.
[0036] Furthermore, in this embodiment, the sealant film is used for radiocarbon dating. 14Since it has a biomass content calculated from the measured value of C, this biomass content can be used as an indicator to identify the raw material origin of the low-density polyethylene resin that makes up the sealant film, and the origin of the raw materials from the time of manufacture to disposal of the film can be confirmed.
[0037] In this embodiment, the melt flow rate (MFR) of the bio-low-density polyethylene resin 10 constituting the sealant film is preferably 0.5 to 4.0 g / 10 min. Furthermore, in order for the sealant film to exhibit a high biomass content and to obtain good tensile strength and seal strength as a packaging bag, the melt flow rate (MFR) of the bio-low-density polyethylene resin 10 is more preferably 0.7 to 3.8 g / 10 min.
[0038] Next, in this embodiment, a sealant film can also be constructed using the bio-low-density polyethylene resin 10 described above and a petroleum-derived low-density polyethylene resin 11 as follows. That is, a sealant film can be constructed in the manner of (A) and (B) below, such that the amount of bio-low-density polyethylene resin 10 blended is 10 to 100 mol% of the total film, and the amount of petroleum-derived low-density polyethylene resin 11 blended is 0 to 90 mol%.
[0039] First, as shown in Figure 2 above, film F1 of (A) can be a single-layer structure consisting of a resin composition in which bio-low-density polyethylene resin 10 and petroleum-derived low-density polyethylene resin 11 are mixed. Here, as described above, the resin composition constituting film F1 contains 10 to 100 mol% of bio-low-density polyethylene resin 10 and 0 to 90 mol% of petroleum-derived low-density polyethylene resin 11. Therefore, when the content of petroleum-derived low-density polyethylene resin 11 is 0 mol%, film F1 will be a single-layer structure consisting only of bio-low-density polyethylene resin 10.
[0040] Figure 3 is a schematic cross-sectional view showing a film having a multilayer structure in which the middle layer is made of bio-low-density polyethylene resin 10. As shown in Figure 3 as film F2 of (B), it is also possible to have a multilayer structure having a middle layer made of a resin composition which is a mixture of bio-low-density polyethylene resin 10 and petroleum-derived low-density polyethylene resin 11, an outer layer made of petroleum-derived low-density polyethylene resin 11 and an inner layer. Here, similar to film F1, The resin composition constituting the middle layer of film F2 contains 10 to 100 mol% of bio-low-density polyethylene resin 10 and 0 to 90 mol% of petroleum-derived low-density polyethylene resin 11. Therefore, when the content of petroleum-derived low-density polyethylene resin 11 is 0 mol%, the middle layer of film F2 consists of a single layer of bio-low-density polyethylene resin 10.
[0041] This configuration allows for a reduction in the proportion of petroleum-derived raw materials used in the resin compositions constituting films F1 and F2, thereby suppressing petroleum-derived carbon dioxide emissions during film manufacturing and disposal. In addition, by using petroleum-derived low-density polyethylene resin 11 in the inner and outer layers constituting film F2 as shown in (B), film F2 can be manufactured, used, and processed with properties similar to existing films. The multilayered film F2 can be manufactured by co-extrusion molding.
[0042] Next, in this embodiment, a laminated film for packaging materials can be constructed using the films F1 and F2 described above. Figure 4 is a schematic cross-sectional view showing an example of a laminated film for packaging materials.
[0043] First, the laminated film 12 for packaging materials has a basic structure in which the aforementioned films F1 and F2 are laminated with the base film 14 as a sealant film 13. Then, the laminated film 12 for packaging materials according to this embodiment is subjected to radiocarbon dating. 14It is preferable that the biomass content, calculated from the measured value of C, is at least 25%. With this configuration, the proportion of petroleum-derived low-density polyethylene resin 11 used in each film F1 and F2 of the sealant film 13 used for heat sealing can be reduced. Furthermore, the laminated film 12 for packaging materials according to this embodiment can conserve petroleum resources and suppress petroleum-derived carbon dioxide emissions during its manufacture and disposal.
[0044] The Japan Bioplastics Association (JBPA) defines biomass plastics as "polymer materials with a molecular weight (Mn) of 1,000 or more obtained by chemical or biological synthesis, containing substances derived from renewable organic resources as raw materials (excluding chemically unmodified non-thermoplastic natural organic polymer materials)." Furthermore, a product can be made to conform to the "Biomass Plastic Mark" by containing 25.0% by weight or more of biomass-derived components in the raw material composition of biomass plastics or biomass-derived thermosetting plastics.
[0045] The laminated film 12 for packaging materials may have an intermediate layer 15. By changing the intermediate layer 15 in various ways, the laminated film 12 for packaging materials can be given various functions, such as gas barrier properties, impact resistance, pinhole resistance, aroma retention, and chemical resistance. For example, the intermediate layer 15 can be a barrier material that suppresses the permeation of water vapor and oxygen. Examples of barrier materials include biaxially oriented polyamide (nylon (ONy)) film as a barrier resin, and biaxially oriented polyethylene terephthalate (OPET (Oriented PolyEthylene Terephthalate) A film may be used. Furthermore, the barrier material may be a vapor-deposited film in which a vapor-deposited film of silica or aluminum is formed on the surface of a barrier resin. Furthermore, the barrier material may be a metal foil such as aluminum.
[0046] The intermediate layer 15 is laminated by bonding it to the sealant film 13 with an adhesive layer 16 and to the base film 14 with an adhesive layer 17. The materials of the adhesive layers 16 and 17 are appropriately selected depending on the type of base material and the bonding method. Examples of lamination (bonding) methods include dry lamination and melt extrusion lamination.
[0047] The adhesive layers 16 and 17, which form the laminate adhesive layers in the dry lamination method, can be made of polyester-based adhesives, polyether-based adhesives, etc., from the perspective of adhesive strength. It is preferable to use a two-component curing urethane adhesive. On the other hand, the materials for the adhesive layer 16 and adhesive layer 17, which become the melt-extruded resin layer in the melt-extruded lamination method, can be polyethylene or polypropylene, and although it depends on the type of substrate, it is preferable to use low-density polyethylene from the viewpoint of substrate adhesion. Furthermore, dry lamination and melt-extruded lamination methods may be used in combination. Before each layer is bonded, the surface may be subjected to surface modification treatments such as corona discharge treatment, ozone treatment, or plasma treatment as needed to improve adhesion, and an anchor coating agent may also be applied.
[0048] A printed layer 18 may be formed on any of the layers constituting the laminated film 12 for packaging material. The printing of characters, figures, symbols, patterns, etc., is not particularly limited as long as it is visible from the outside of the packaging container, and surface printing is also acceptable. In the layer configuration illustrated in Figure 4, the printed layer 18 is formed on the inside of the base film 14. A white underlayer may be provided on the printed layer 18. The printed layer 18 is formed by printing using gravure printing ink or the like using printing methods such as gravure printing, letterpress printing, screen printing, transfer printing, and flexographic printing.
[0049] Furthermore, the laminated film 12 for packaging materials may have an outer layer (not shown) further laminated onto the base film 14.
[0050] As the base film 14, various resin films and sheets such as polyethylene resins, polypropylene resins, cyclic polyolefin resins, polystyrene resins, acrylonitrile-styrene copolymers (AS resins), acrylonitrile-butadiene-styrene copolymers (ABS resins), polyvinyl chloride resins, fluororesins, poly(meth)acrylic resins, polycarbonate resins, polyester resins such as polyethylene terephthalate and polyethylene naphthalate, polyamide resins such as various types of nylon, polyimide resins, polyamide-imide resins, polyarylphthalate resins, silicone resins, polysulfone resins, polyphenylene sulfide resins, polyethersulfone resins, polyurethane resins, acetal resins, and cellulose resins can be used.
[0051] The base film 14 is preferably made of biaxially oriented polypropylene (OPP) or biaxially oriented polyethylene terephthalate (OPET). Biaxially oriented polypropylene film has excellent moisture resistance, water resistance, and chemical resistance, is highly versatile, and is inexpensive. Biaxially oriented polyethylene terephthalate has low hygroscopicity and excellent scratch resistance, heat resistance, water resistance, and aroma retention. The laminated film 12 for packaging materials using these base films 14 has tensile strength, seal strength, and stiffness suitable for packaging bags, such as flexible packaging bags, and exhibits excellent processability.
[0052] Furthermore, in this embodiment, the raw material for the biaxially oriented polyethylene terephthalate used in the base film 14 may be plant-derived.
[0053] Next, the manufacturing process of the plant-derived base film 14 that constitutes the laminated film 12 for packaging materials according to this embodiment will be described. Figure 5 is a flowchart illustrating the manufacturing process of a plant-derived polyethylene terephthalate film. Here, an example is shown in which sugarcane is used as the starting material for the plant-derived polyethylene terephthalate film, i.e., bio-PET film F3 (see Figure 1). However, the raw material for the bio-PET film F3 according to this embodiment is not limited to sugarcane, but can be any plant that is a raw material for the manufacture of polyethylene terephthalate resin, and furthermore, it can be any renewable, bio-derived organic resource that excludes fossil resources.
[0054] First, by going through steps S101 and S102 in Figure 1 described above, Bioethylene 3 is obtained.
[0055] Bioethylene oxide 4 (1,2-epoxyethane) is obtained by oxidation of bioethylene 3 (step S201). Bioethylene oxide 4 is obtained, for example, by catalytic gas-phase oxidation of bioethylene 3 with molecular oxygen or a molecular oxygen-containing gas while pressurized and heated to 1-3 MPa and 200-300°C in the presence of a silver catalyst. Bioethylene oxide 4 may also be produced by reacting bioethylene 3 with hydrogen peroxide or a peracid.
[0056] Bioethylene oxide 4 is hydrolyzed under acid catalyst to obtain plant-derived bioethylene glycol 5 (MEG: Mono Ethylene Glycol) (ethane-1,2-diol) (Step S202). The biomass content of this bio-MEG 5 can be 100%.
[0057] On the other hand, paraxylene 6, a secondary product of petroleum, is oxidized and purified to a high degree of purity to obtain purified terephthalic acid (PTA) 7 (step S203).
[0058] Bio-PET resin 19 containing plant-derived raw materials is obtained by condensation polymerization of bio-MEG5 and purified terephthalic acid (PTA) 7 (Step S204). The bio-PET resin 19 has a biomass content of 30%, as 30% of its raw materials are bio-MEG5 and 70% are purified terephthalic acid (PTA) 7.
[0059] A bio-PET film F3 is formed by the deposition of bio-PET resin 19 (step S205). The bio-PET film F3 thus obtained is then used as a base film 14 constituting the laminated film 12 for packaging materials, as needed. This embodiment further reduces the proportion of petroleum-derived resin used in the resin composition of the laminated film 12 for packaging materials, thereby reducing the consumption of petroleum, a fossil resource (a depletable resource), and contributing to the prevention of global warming by reducing carbon dioxide emissions. More specifically, the bio-PET film F3 can reduce CO2 emissions by approximately 10% compared to petroleum-derived PET film throughout its entire lifecycle, from raw material procurement to disposal.
[0060] Furthermore, the bio-PET film F3 has 2 carbon atoms derived from bio-MEG5 and 8 carbon atoms derived from purified terephthalic acid (PTA) 7, resulting in a biomass content of 20%. On the other hand, of the PET constituent units with a molecular weight of 192, the molecular weight derived from ethylene glycol is 60. Therefore, the biomass content by gravimetric method is 60 / 192 = 31.25%.
[0061] Figure 6 is a schematic cross-sectional view showing an example of a packaging bag made by heat-sealing a laminated film 12 for packaging material. The laminated film 12 for packaging material is made into a bag by heat-sealing (heat-pressing) the outer edges. In this example, the laminated film 12 for packaging material is shown as being composed of two layers: a sealant film 13 and a base film 14. The adhesive layer is not shown in this diagram.
[0062] One laminated film 12 for packaging material is folded, or two laminated films 12 for packaging material are superimposed, so that the surfaces of the sealant film 13 which forms the inner layer of the laminated film 12 for packaging material face each other, and the outer edges are heat-sealed. Methods of heat sealing that can be used include bar sealing, rotary roll sealing, belt sealing, impulse sealing, high-frequency sealing, ultrasonic sealing, etc. Figure 6 shows an example where two laminated films 12A and 12B for packaging material are superimposed.
[0063] Heating and pressurizing are applied from the side of the base film 14A and 14B, which will form the outer layer of the two laminated packaging film 12A and 12B, using a heating roller or the like (not shown). The heat melts the sealant film 13A and 13B, and the pressure causes the sealant film 13A and 13B to adhere tightly to each other. As a result, a seal portion 21 is formed at the outer edges of the two laminated packaging film 12A and 12B.
[0064] Such seal portions 21 are formed on three sides of, for example, two rectangular laminated packaging films 12A and 12B, with the remaining side serving as the filling opening for the contents. Then, by forming another seal portion 21 on the side after the contents have been filled through the filling opening, a manufactured packaging bag (four-sided sealed bag 20) is formed.
[0065] Figure 7 is a perspective view showing a four-sided sealed bag 20 as an example of a packaging bag formed using the laminated film 12 for packaging materials according to this embodiment. In this way, a flexible packaging bag can be formed using a flexible packaging material consisting of the sealant film 13 and the base film 14 according to this embodiment, for example, in which frozen foods such as fried rice can be filled and packaged.
[0066] This configuration allows for a reduction in the proportion of petroleum-derived raw materials used in the laminated film 12 for packaging materials that constitutes the packaging bag, thereby conserving petroleum resources and suppressing petroleum-derived carbon dioxide emissions during the manufacturing and disposal of the packaging bag. In particular, since flexible packaging bags tend to be disposable, the laminated film 12 for packaging materials according to this embodiment, which reduces the amount of petroleum resources used and suppresses petroleum-derived carbon dioxide emissions, can provide an environmentally friendly packaging bag. Furthermore, as described above, the processability and physical properties of the laminated film 12 for packaging materials according to this embodiment are comparable to those of petroleum-derived materials. Therefore, according to the configuration of this embodiment, it is possible to provide a packaging bag that contains bio-low-density polyethylene resin 10, which conserves petroleum resources and reduces environmental impact, and has processability and physical properties, especially durability, that are comparable to those of petroleum-based resins.
[0067] Furthermore, the packaging bag may have opening lines provided at its edges, etc., by a laser or the like. In addition, the packaging bag according to this embodiment may be optionally fitted with a one-piece or two-piece spout, a fastener for resealing, etc. Naturally, bio-low-density polyethylene resin 10 or bio-PET resin 19 may be used as the material for these.
[0068] In addition to the four-sided sealed bag 20 illustrated in Figure 7, various forms of packaging bags according to this embodiment can be manufactured by heat sealing using side-seal type, two-sided sealed type, three-sided sealed type, envelope-type sealed type, gusset-type sealed type (pillow-type), pleated-type sealed type, flat-bottom sealed type, square-bottom sealed type, and others. Furthermore, in this embodiment, by using the laminated film 12 for packaging materials described above, containers including self-standing packaging bags (standing pouches), tube containers, liquid paper containers, etc., as well as container lids, container labels, etc. Moreover, the contents of the packaging bags according to this embodiment are not limited to the illustrated food and beverages, but can also contain cosmetics, pharmaceuticals, general merchandise, etc., further reducing the proportion of petroleum-derived materials used and significantly suppressing petroleum-derived carbon dioxide emissions.
[0069] In this embodiment, it is preferable that the biomass content of the entire packaging material be 25% or more. Therefore, when a bio-PET film F3 with a biomass content of 20% is used for the base film 14, a configuration in which the sealant film 13 contains, for example, about 35% bio-low-density polyethylene resin 10 can be considered. On the other hand, when the biomass content of the base film 14 is 0%, the bio-low-density polyethylene resin 1 of the sealant film 13 is 1 The proportion of 0 is increased to, for example, 70%. In this way, in this embodiment, the biomass content of the entire packaging material is made to be at least 25% or more.
[0070] The present invention can be further provided in the following embodiments as a means for solving the above-mentioned problems. The present invention relates to a laminated film for packaging materials, comprising a sealant film made of a resin composition containing a plant-derived low-density polyethylene resin obtained by polymerizing plant-derived ethylene by a high-pressure method, and a base film, wherein the laminated film for packaging materials is radiocarbon dating 14 It is characterized by having a biomass content of at least 25%, calculated from the measured value of C. Furthermore, the plant-derived low-density polyethylene resin is characterized by having a biomass content of 10 to 100%. Furthermore, the base film is characterized by being a film made of a resin composition containing a plant-derived polyethylene terephthalate resin obtained by condensation polymerization of plant-derived ethylene glycol and petroleum-derived terephthalic acid. Furthermore, the sealant film is characterized by being composed of either (A) or (B) below, using the resin composition containing 10 to 100 mol% of the plant-derived low-density polyethylene resin and 0 to 90 mol% of the petroleum-derived low-density polyethylene resin. (A) A single layer structure obtained by mixing the resin composition and the petroleum-derived low-density polyethylene resin. (B) A multilayer structure in which the middle layer is a layer obtained by mixing the resin composition with the petroleum-derived low-density polyethylene resin, and the outer layer and inner layer are made of the petroleum-derived low-density polyethylene resin. Furthermore, the present invention is characterized by further comprising an intermediate layer between the sealant film and the base film. Furthermore, the packaging bag of the present invention is characterized by being made using the laminated film for packaging materials described above. [Examples]
[0071] The present disclosure will be described in more detail and specifically below with reference to examples. However, the present disclosure is not limited to the following examples.
[0072] [Example 1] (1) Resin composition Low-density polyethylene (LC525 manufactured by Nippon Polyethylene Co., Ltd.: density d = 0.923 g / cm³) 3 , melt flow rate (MFR) = 3.5g / 10min) 50.0 parts by weight, OMAS low-density polyethylene (SEB853, manufactured by Braschem Co., Ltd.: density d = 0.923 g / cm³) 3 (Melt flow rate (MFR) = 2.7g / 10 min) 50.0 parts by weight and sufficient A resin composition was prepared by kneading the materials together.
[0073] (2) Film Next, using the resin composition prepared in (1), a single-layer film according to this example with a thickness of 30 μm was manufactured using a single-layer top-blowing air-cooled inflation co-extrusion film manufacturing machine. That is, the single-layer film according to Example 1 is a film F1 containing bio-low-density polyethylene as shown in Figure 2. Corona discharge surface treatment (hereinafter referred to as corona treatment) was applied to one side of the manufactured single-layer film.
[0074] (3) Laminated material A 15 μm thick biaxially oriented nylon 6 film is corona-treated on one side. A desired printed pattern is formed on the corona-treated surface using a standard gravure ink composition and a gravure printing method. Then, a two-component curing polyurethane-based laminating adhesive is applied to the entire surface including the printed pattern. The agent was applied using the gravure roll coating method to a thickness of 4.0 g / m². 2 (To make it dry) A laminating adhesive layer was formed by coating, then the corona-treated surface of the single-layer film manufactured in (2) was placed opposite the laminating adhesive layer, and then the two were dry-laminated to form a laminated material.
[0075] (4)Flexible packaging products Next, two sheets of the laminated material manufactured in (3) were prepared, and the sides of the film from (2) on each sheet were placed facing each other and then heat-sealed on three sides to form a seal portion 21 and to manufacture a three-sided sealed flexible packaging bag having an opening at the top. Snack food was filled and packaged into the three-sided sealed flexible packaging bag through the opening, and then the end of the opening was heat-sealed to form a seal portion 21 to manufacture a flexible packaged product.
[0076] [Example 2] (1) Resin composition Low-density polyethylene (LC522 manufactured by Nippon Polyethylene Co., Ltd.: density d = 0.923 g / cm³) 3, melt flow rate (MFR) = 4.0 g / 10 min) 30.0 parts by weight, OMAS low-density polyethylene (SPB681, manufactured by Braschem Co., Ltd.: density d = 0.922 g / cm³) 3 Melt flow rate (MFR) = 3.8g / 10 min) 70.0 parts by weight and sufficient A resin composition was prepared by kneading the materials together.
[0077] (2) Film Next, using the resin composition prepared in (1), a single-layer film according to this example with a thickness of 50 μm was manufactured using a single-layer top-blowing air-cooled inflation co-extrusion film manufacturer. That is, the single-layer film according to Example 2 is a film F1 containing bio-low-density polyethylene as shown in Figure 2. One side of the manufactured single-layer film was subjected to corona treatment.
[0078] (3) Laminated material A biaxially oriented PET film with a thickness of 12 μm is corona-treated on one side. A desired printed pattern is formed on the corona-treated surface using a gravure printing method with a standard gravure ink composition. Then, a two-component curing polyurethane-based laminating adhesive is applied to the entire surface, including the printed pattern, using a gravure roll coating method to a thickness of 4.0 g / m². 2 (To dry state) A laminating adhesive layer was formed by applying a coating, and then the corona-treated surface of the single-layer film manufactured in (2) was placed opposite the laminating adhesive layer surface and superimposed on it. After that, the two were dry-laminated to form a laminated material.
[0079] (4)Flexible packaging products Next, two sheets of the laminated material manufactured in (3) were prepared, and the sides of the film from (2) on each sheet were placed facing each other and then heat-sealed on three sides to form a seal portion 21 and to manufacture a three-sided sealed flexible packaging bag having an opening at the top. Snack food was filled and packaged into the three-sided sealed flexible packaging bag through the opening, and then the end of the opening was heat-sealed to form a seal portion 21 to manufacture a flexible packaged product.
[0080] [Example 3] (1) Resin composition First, the following resin compositions (a), (b), and (c) were prepared. (i) Resin composition constituting the first layer Low-density polyethylene (LC522 manufactured by Nippon Polyethylene Co., Ltd.: density d = 0.923 g / cm³) 3 Melt flow rate (MFR) = 4.0 g / 10 min) 100.0 parts by weight, A resin composition was prepared by thoroughly kneading 0.5 parts by weight of silica and 0.05 parts by weight of erucic acid amide. (b) Resin composition constituting the second layer Biomass low-density polyethylene (SPB681 manufactured by Braschem Co., Ltd.: density d = 0.922 g / cm³) 3 Melt flow rate (MFR) = 3.8 g / 10 min) 100.0 parts by weight We prepared it. (h) Resin composition constituting the third layer Low-density polyethylene (LC522 manufactured by Nippon Polyethylene Co., Ltd.: density d = 0.923 g / cm³) 3 Melt flow rate (MFR) = 4.0 g / 10 min) 100.0 parts by weight, A resin composition was prepared by thoroughly kneading 0.5 parts by weight of silica and 0.05 parts by weight of erucic acid amide.
[0081] (2) Film Next, using each of the resin compositions prepared in (1), these were co-extruded using a three-layer, three-type top-blowing air-cooled inflation co-extrusion film press to form a film with layers of resin composition (a) to 10 μm, layers of resin composition (b) to 30 μm, and layers of resin composition (c) to 10 μm, thereby producing a multilayer laminated film according to this embodiment, consisting of a co-extruded inflation film with a total thickness of 50 μm across the three layers. That is, the multilayer laminated film according to Example 3 is a film F2 having a multilayer structure in which the middle layer is made of bio-low-density polyethylene resin 10, as shown in Figure 3. The first layer (a) of the manufactured multilayer laminated film was subjected to corona treatment.
[0082] (3) Laminated material A biaxially oriented PET film with a thickness of 12 μm is corona-treated on one side. A desired printed pattern is formed on the corona-treated surface using a gravure printing method with a standard gravure ink composition. Then, a two-component curing polyurethane-based laminating adhesive is applied to the entire surface, including the printed pattern, using a gravure roll coating method to a thickness of 4.0 g / m². 2 (To dry state) A laminating adhesive layer was formed by applying a coating, and then the corona-treated surface of the layer made of the resin composition of the first layer (a) of the multilayer laminated resin film manufactured in (2) was placed opposite the surface of the laminating adhesive layer, and thereafter, the two were dry-laminated to produce a laminated material.
[0083] (4)Flexible packaging products Next, two sheets of the laminated material manufactured in (3) were prepared, and the faces of the third layer (c) of each were placed facing each other. Then, the edges around the outer circumference were heat-sealed on three sides to form a seal portion 21, and a three-sided sealed flexible packaging bag with an opening at the top was manufactured. Snack food was filled and packaged into the three-sided sealed flexible packaging bag through the opening, and then the edges of the opening were heat-sealed to form a seal portion 21 to manufacture a flexible packaged product.
[0084] [Example 4] (1) Resin composition Low-density polyethylene (LC520 manufactured by Nippon Polyethylene Co., Ltd.: density d = 0.923 g / cm³) 3 , melt flow rate (MFR) = 3.6 g / 10 min) 30.0 parts by weight, OMAS low-density polyethylene (SEB853, manufactured by Braschem Co., Ltd.: density d = 0.923 g / cm³) 3 The melt flow rate (MFR) is 2.7 g / 10 mins, and 70.0 parts by weight are used in sufficient quantities. A resin composition was prepared by kneading the materials together.
[0085] (2) Film Next, using the resin composition prepared in (1), a single-layer film according to this example with a thickness of 50 μm was manufactured using a single-layer top-blowing air-cooled inflation co-extrusion film manufacturer. That is, the single-layer film according to Example 4 is a film F1 containing bio-low-density polyethylene as shown in Figure 2. One side of the manufactured single-layer film was subjected to corona treatment.
[0086] (3) Laminated material One side of a 12 μm thick biaxially oriented PET film is corona-treated, and a two-component polyurethane-based laminating adhesive is applied to the corona-treated side at a thickness of 3.0 g / m². 2 (dry form Apply the adhesive in the specified state to form an adhesive layer, then lay a 12 μm thick biaxially oriented PET film, which has been corona-treated on both sides, onto the surface of the adhesive layer, and then, similarly to the above, apply a two-component curing polyurethane-based laminating adhesive at a thickness of 3.0 g / m² to the surface of the biaxially oriented PET film that has been corona-treated on both sides and laminated as described above. 2 Apply until dry. An adhesive layer was formed to obtain a base film 14. The adhesive layer surface of the base film 14 and the corona-treated surface of the single-layer film produced in (2) were placed opposite each other and superimposed to obtain a multilayer laminated film of the base film 14 of this embodiment.
[0087] (4)Flexible packaging products Next, two sheets of the laminated material manufactured in (3) were prepared, and the sides of the film from (2) on each sheet were placed facing each other and then heat-sealed on three sides to form a seal portion 21 and to manufacture a three-sided sealed flexible packaging bag having an opening at the top. Snack food was filled and packaged into the three-sided sealed flexible packaging bag through the opening, and then the end of the opening was heat-sealed to form a seal portion 21 to manufacture a flexible packaged product.
[0088] [Example 5] (1) Resin composition First, the following resin compositions (a), (b), and (c) were prepared. (i) Resin composition constituting the first layer Low-density polyethylene (LC522 manufactured by Nippon Polyethylene Co., Ltd.: density d = 0.923 g / cm³) 3 Melt flow rate (MFR) = 4.0 g / 10 min) 100.0 parts by weight, A resin composition was prepared by thoroughly kneading 0.5 parts by weight of silica and 0.05 parts by weight of erucic acid amide. (b) Resin composition constituting the second layer Biomass low-density polyethylene (SPB681 manufactured by Braschem Co., Ltd.: density d = 0.922 g / cm³) 3 Melt flow rate (MFR) = 3.8 g / 10 min) 100.0 parts by weight We prepared it. (h) Resin composition constituting the third layer Low-density polyethylene (LC522 manufactured by Nippon Polyethylene Co., Ltd.: density d = 0.923 g / cm³) 3 Melt flow rate (MFR) = 4.0 g / 10 min) 100.0 parts by weight, A resin composition was prepared by thoroughly kneading 0.5 parts by weight of silica and 0.05 parts by weight of erucic acid amide.
[0089] (2) Film Next, using each of the resin compositions prepared in (1), these were co-extruded using a three-layer, three-type top-blowing air-cooled inflation co-extrusion film press to form a film with layers of resin composition (a) to 10 μm, layers of resin composition (b) to 30 μm, and layers of resin composition (c) to 10 μm, thereby producing a multilayer laminated film according to this embodiment, consisting of a co-extruded inflation film with a total thickness of 50 μm across the three layers. That is, the multilayer laminated film according to Example 5 is a film F2 having a multilayer structure in which the middle layer is made of bio-low-density polyethylene resin 10, as shown in Figure 3. The first layer (a) of the manufactured multilayer laminated film was subjected to corona treatment.
[0090] (3) Laminated material One side of a 12 μm thick biaxially oriented PET film is corona-treated, and a two-component polyurethane-based laminating adhesive is applied to the corona-treated side at a thickness of 3.0 g / m².2 (dry form Apply the adhesive in the specified state to form an adhesive layer, then lay a 15 μm thick biaxially oriented nylon 6 film, which has been corona-treated on both sides, onto the surface of the adhesive layer, and then, similarly to the above, apply a two-component curing polyurethane-based laminating adhesive at a thickness of 3.0 g / m² to the surface of the biaxially oriented nylon 6 film that has been corona-treated on both sides and laminated as described above. 2 (To become dry) The adhesive layer was applied to form an adhesive layer, and a base film 14 was obtained. The adhesive layer surface of the base film 14 and the corona-treated surface of the co-extruded multilayer laminated film of (2) were placed facing each other and superimposed to obtain a multilayer laminated film of the base film 14 of this embodiment.
[0091] (4)Flexible packaging products Next, two sheets of the laminated material manufactured in (3) were prepared, and the faces of the third layer (c) of each were placed facing each other. Then, the edges around the outer circumference were heat-sealed on three sides to form a seal portion 21, and a three-sided sealed flexible packaging bag with an opening at the top was manufactured. The rapidly frozen fried rice was filled and packaged inside the three-sided sealed flexible packaging bag through the opening, and then the edges of the opening were heat-sealed to form a seal portion 21 to manufacture a flexible packaging product.
[0092] [Example 6] (1) Resin composition Low-density polyethylene (LC525 manufactured by Nippon Polyethylene Co., Ltd.: density d = 0.923 g / cm³) 3 , melt flow rate (MFR) = 3.5g / 10min) 20.0 parts by weight, OMAS low-density polyethylene (SEB853, manufactured by Braschem Co., Ltd.: density d = 0.923 g / cm³) 3 (Melt flow rate (MFR) = 2.7g / 10 min) 80.0 parts by weight and sufficient A resin composition was prepared by kneading the materials together.
[0093] (2) Film Next, using each resin composition prepared in (1), a single-layer film according to this example with a thickness of 30 μm was manufactured using a single-layer top-blowing air-cooled inflation co-extrusion film manufacturer. That is, the single-layer film according to Example 6 is a film F1 containing bio-low-density polyethylene as shown in Figure 2. One side of the manufactured single-layer film was subjected to corona treatment.
[0094] (3) Laminated material One side of a 12 μm thick biaxially oriented biomass PET film (BioPET Film F3) is corona-treated. A desired print pattern is formed on the corona-treated surface using a gravure printing method with a standard gravure ink composition. Then, a two-component curing polyurethane-based laminating adhesive is applied to the entire surface, including the print pattern, using a gravure roll coating method to a thickness of 4.0 g / m². 2 Coat it so that it becomes dry to form a laminating adhesive layer, then Next, the corona-treated surface of the single-layer film manufactured in (2) was placed opposite the adhesive layer surface for lamination, and then the two were dry-laminated to form a laminated material.
[0095] (4)Flexible packaging products Next, two sheets of the laminated material manufactured in (3) were prepared, and the sides of the film from (2) on each sheet were placed opposite each other and then heat-sealed on three sides to form a seal portion 21 and to manufacture a three-sided sealed flexible packaging bag having an opening at the top. The rapidly frozen fried rice was filled and packaged inside the three-sided sealed flexible packaging bag through the opening, and then the end of the opening was heat-sealed to form a seal portion 21 to manufacture a flexible packaging product.
[0096] As detailed above, the films F1 and F2 of the low-density polyethylene resin of this disclosure consist of a resin composition containing a bio-low-density polyethylene resin 10 obtained by a high-pressure polymerization method. These films F1 and F2 then combine with the sealant film 13. The packaging material is made of a laminated film 12 which is laminated with a base film 14, and the packaging bag is made of this laminated film 12. [Industrial applicability]
[0097] This disclosure can be applied to films made of polyethylene resin, and to all products using polyethylene resin, such as packaging bags and containers made from this film. [Explanation of Symbols]
[0098] 10 Bio-low-density polyethylene resin 11. Petroleum-derived low-density polyethylene resin 12 Laminated film for packaging materials 13. Sealant film 14. Base film 19 Bio-PET resin 20 square-sided sealed bags (packaging bags) F1, F2 film (sealant film) F3 Bio PET Film
Claims
1. A laminated film for packaging materials, A sealant film made from a resin composition containing a plant-derived low-density polyethylene resin obtained by polymerizing plant-derived ethylene under high pressure, An intermediate layer to provide gas barrier properties, It has a base film having a printed pattern, The aforementioned base film is a polypropylene resin or a polyester resin. The substrate film having the printed pattern, the intermediate layer for providing the gas barrier properties, and the sealant film are laminated together via a laminating adhesive. The aforementioned laminated film for packaging material is subjected to radiocarbon dating. 14 The biomass content calculated from the measurement value of C is at least 25%, The aforementioned plant-derived low-density polyethylene resin has a biomass content of 10 to 100%, The sealant film does not contain 0.2% by mass or more silica, 5.0% by mass or more titanium dioxide, ionomer, or ethylene-methacrylic acid copolymer. The sealant film is a laminated film for packaging materials characterized in that the resin comprising the sealant film is composed of either (A) or (B) below, using the resin composition which consists only of 10 to 100% by weight of the plant-derived low-density polyethylene resin and 0 to 90% by weight of the petroleum-derived low-density polyethylene resin. (A) Single layer structure consisting of the resin composition (B) A multilayer structure in which the middle layer is made of the resin composition, and the outer and inner layers are made of the petroleum-derived low-density polyethylene resin.
2. The laminated film for packaging materials according to claim 1, characterized in that the base film is a film made of a resin composition containing a plant-derived polyethylene terephthalate resin obtained by condensation polymerization of plant-derived ethylene glycol and petroleum-derived terephthalic acid.
3. A packaging bag characterized by being made using the laminated film for packaging materials described in claim 1 or 2.