Laminated film for packaging materials, and packaging bag

Abstract

To provide a laminated film for packaging material which saves an oil resource, and is friendly to the environment due to reduction of the amount of carbon dioxide to be emitted, and to provide a packaging bag using the same which has processing suitability and physical properties, in particular, durability not inferior to a packaging bag of a petroleum-based resin.SOLUTION: There is provided a laminated film 12 for packaging material in which a sealant film 13 formed from a resin composition containing a plant-derived low-density polyethylene resin obtained by polymerization plant-derived ethylene with a high pressure method and a base material film 14 are laminated, where the laminated film 12 for packaging material has at least 25% of a biomass degree calculated from a measurement value of radioactive carbon dating 14C.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a laminated film for packaging materials and a packaging bag, and more particularly, to a laminated film for packaging materials in which a film made of a resin composition containing a plant-derived low-density polyethylene resin is laminated, and a packaging bag using the film.

Background Art

[0002] For example, flexible packaging (light packaging), which is widely used as a packaging form for frozen foods such as dumplings, baked shumai, fried rice, and pizza, is composed of a flexible packaging material made of a sealant film and a base film. However, most of the raw materials of flexible packaging materials are derived from petroleum, and it is required to address environmental problems and conserve depleting resources such as petroleum. And, a packaging bag (for example, Patent Document 1) containing a biodegradable resin composition containing a predetermined amount of an ethylene-α-olefin copolymer and a polymer having an epoxy group in a polylactic acid-based resin as a carbon-neutral material for the purpose of reducing the amount of petroleum resources used for packaging materials is known.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By including a biodegradable resin other than petroleum-derived raw materials in the resin composition constituting the packaging bag, the ratio of petroleum-derived raw materials can be lowered. However, such a packaging bag is significantly inferior in terms of tensile strength, tear strength, seal strength, and processing suitability such as stiffness compared to those made of petroleum-based resins, making it difficult to improve productivity and also difficult to improve durability.

[0005] Therefore, an object of the present invention is to provide a laminated film for packaging materials that saves petroleum resources and reduces carbon dioxide emissions, is environmentally friendly, and a packaging bag using the film, which has processing suitability and physical properties, particularly durability, comparable to those of a packaging bag made of a petroleum-based resin.

Means for Solving the Problems

[0006] In order to solve the above problems, the present invention provides a laminated film for packaging materials, which is formed 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 of at least 25% calculated from the measured value of radiocarbon dating 14 C.

[0007] Furthermore, the plant-derived low-density polyethylene resin is characterized by having a biomass degree of 10 to 100%.

[0008] Furthermore, 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.

[0009] Furthermore, the sealant film is composed of any one of the following (A) and (B) 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 in which the resin composition and the 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 the petroleum-derived low-density polyethylene resin are mixed, and the outer layer and the inner layer are made of the petroleum-derived low-density polyethylene resin (B) A multilayer structure in which the middle layer is a layer in which the resin composition and the petroleum-derived low-density polyethylene resin are mixed, and the outer layer and the inner layer are made of the petroleum-derived low-density polyethylene resin

[0010] Furthermore, it is characterized in that an intermediate layer is further provided between the sealant film and the base film.

[0011] Furthermore, the packaging bag of the present invention is characterized in that it is made using the above-described laminated film for packaging materials.

Advantages of the Invention

[0012] According to the present invention, there is provided a laminated film for packaging materials, in which 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 are laminated. The laminated film for packaging materials has a biomass degree of at least 25% calculated from the measured value of radiocarbon dating 14 C. Therefore, it is possible to reduce the amount of petroleum resources frequently used as raw materials for the sealant film constituting the laminated film for packaging materials, and to suppress the carbon dioxide emissions derived from petroleum during film production and disposal. Furthermore, since it is not inferior in physical properties to petroleum-derived low-density polyethylene resin, it can be the same as the manufacturing process of existing laminated films for packaging materials, and the raw material 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 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.

[0013] 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 materials in 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.

[0014] 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 suitable tensile strength, seal strength, and stiffness as a packaging bag, for example, a flexible packaging bag, and exhibits excellent processability.

[0015] 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 any 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 can be achieved. In addition, since a petroleum-derived low-density polyethylene resin is used 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 processability can be provided.

[0016] 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.

[0017] Furthermore, since the packaging bag of the present invention is made using the above-described laminated film for packaging materials, the usage ratio of the petroleum-derived low-density polyethylene resin in the laminated film for packaging materials that constitutes the packaging bag can be reduced, thereby reducing the amount of petroleum resources used and suppressing the amount of carbon dioxide emissions derived from petroleum during the production and disposal of the packaging bag. Furthermore, the usage ratio of petroleum-derived raw materials that constitute the numerous disposable packaging bags in the world can be reduced. Furthermore, as described above, the processability and physical properties of the laminated film for packaging materials are comparable to those derived from petroleum. Therefore, it is possible to provide a packaging bag that contains a plant-derived low-density polyethylene resin with reduced petroleum resources and reduced environmental impact, and has processability and physical properties, particularly durability, comparable to those of petroleum-based resins.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Modes for Carrying Out the Invention

[0019] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0020] The flexible packaging widely used in foods, daily necessities, etc. is composed of a laminated film. Some laminated films laminate a sealant film (heat-sealing film) as a heat-sealing material for the inner surface of the flexible packaging on a base film. For example, a polyester-based resin is used as the material for the base film. On the other hand, a low-density polyethylene (LDPE: Low Density PolyEthylene (PE-LD)) resin is used as the material for the sealant film. The low-density polyethylene resin is inexpensive and excellent in flexibility, transparency, extrusion coating property, heat adhesiveness, etc.

[0021] Thus, low-density polyethylene resin and polyester-based resin are often used as the materials for the laminated film. And these low-density polyethylene resins and polyester-based resins are manufactured using petroleum as a starting material. For example, low-density polyethylene is obtained by polymerizing ethylene (ethene) obtained by refining crude oil or the like under high-temperature and high-pressure conditions such as 300 °C and 2000 atmospheres. It is polymerized.

[0022] On the other hand, awareness of environmental problems such as the depletion of resources such as petroleum and global warming due to the increase in carbon dioxide emissions has been increasing year by year. In such circumstances, the use of petroleum-derived low-density polyethylene resin, etc. means that a large amount of carbon dioxide fixed in petroleum is discharged into the atmosphere from the production to the disposal of petrochemical products, so no consideration is given to the environment.

[0023] Against such a backdrop, technologies for manufacturing plastics from plants, which are carbon-neutral and renewable resources, have been developed, and a technology for producing polyethylene, the most widely used plastic, using biomass-based sugarcane as a starting material has been established (edited by the Processing Technology Research Society, Convertec 2009.9, P63-67). Note that carbon neutral 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 circulation in the environment.

[0024] Next, the manufacturing process of the sealant film that constitutes the laminated film for packaging materials according to the present embodiment will be described. FIG. 1 is a flowchart illustrating the manufacturing process of a low-density polyethylene film derived from sugarcane, and FIG. 2 is a cross-sectional view schematically showing a sealant film containing a low-density polyethylene resin derived from sugarcane according to the present embodiment. Note that in the present embodiment, an example is shown in which sugarcane is used as a 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 the present embodiment are not limited to sugarcane, and any plant that can be used as a raw material for manufacturing a low-density polyethylene resin may be used, and further, any renewable, bio-derived organic resource excluding fossil resources may be used.

[0025] As shown in FIG. 1, first, the sugar solution squeezed from sugarcane harvested in the field is heated and concentrated, and a mixture of crystallized raw sugar and sugarcane molasses 1, which is a non-crystalline substance, is separated by a centrifuge. Sugarcane molasses 1, which is a by-product generated during the production of this sugar, is used as a raw material.

[0026] Sugarcane molasses 1 is diluted with water to an appropriate concentration, fermented by yeast, and distilled to produce bioethanol 2 (step S101).

[0027] Bioethanol 2 is heated in the presence of a catalyst, and bioethylene 3 derived from plants is obtained by an intramolecular dehydration reaction (step S102).

[0028] Bioethylene 3 (monomer) is polymerized by a high-pressure method to obtain a bio-low density polyethylene resin 10 derived from plants (step S103).

[0029] Thus, 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. And it has been confirmed that ethylene and polyethylene derived from plants have the same quality as ethylene and polyethylene derived from petroleum. Therefore, the bio-low density polyethylene resin 10 can be produced in the same manner as when a low density polyethylene resin is produced from ethylene derived from petroleum. 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.

[0030] The bio-low density polyethylene resin 10, similar to the low density polyethylene resin derived from petroleum, has a density d of 0.910 to 0.925 g / cm 3 , a melt flow rate (MFR) of 0.5 to 8.0 g / 10 min, more preferably in the range of 0.7 to 5.0 g / 10 min.

[0031] Note that the density (d, unit: g / cm 3) A 1-mm-thick sheet obtained by press molding at 150°C was used and measured 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 the conditions of a test temperature of 190°C and a test load of 21.18 N. The value of the melt flow rate is the amount (g) extruded in 10 minutes when a cylinder with a 2-mm-diameter hole at the bottom is heated to 190°C and the measurement target placed in the cylinder is subjected to a load of 21.18 N. And since the viscosity at the time of melting increases as the degree of polymerization of the polymer increases, the numerical value of the melt flow rate tends to decrease.

[0032] A sealant film constituting a laminated film for packaging materials is manufactured using 10 parts of a bio-low density polyethylene resin having these physical properties. At that time, if necessary, a petroleum-derived low density polyethylene resin 11 is mixed. The bio-low density polyethylene resin 10 is mixed with the petroleum-derived low density polyethylene resin 11 so as to be contained in an appropriate ratio of 10 to 100% by mass.

[0033] A resin composition containing 10 to 100 mol% of the bio-low density polyethylene resin 10 and mixed with the petroleum-derived low density polyethylene resin 11 is formed into a film, whereby a film F1 containing bio-low density polyethylene as shown in FIG. 2 is formed (step S104).

[0034] Although there is no particular limitation on the method for manufacturing the sealant film constituting the laminated film for packaging materials according to the present embodiment, melt extrusion molding is preferably used, and the inflation method, the flat die method, etc. are preferably used. Furthermore, the sealant film may be processed into a multilayer in which a plurality of layers are stacked, and in that case, the coextrusion method is preferably used.

[0035] In this embodiment, the sealant film that constitutes the 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.

[0036] And in this embodiment, radiocarbon dating 14 The bio-low density polyethylene resin 10 having a biomass degree of 80 to 100% by

[0037] Here, it is difficult to distinguish between resins derived from plants (biomass) and resins derived from petroleum based on physical properties such as molecular weight, mechanical properties, and thermal properties. Therefore, the biomass degree is used as a general index for identifying the content ratio of resins derived from plants in the resin composition. This biomass degree utilizes the fact that the carbon of petroleum-derived resins does not contain (remain) 14 C (radiocarbon 14, half-life 5730 years), and this 14 C 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.

[0038] In the first step of measuring this biomass degree, the 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. Then, this graphite is based on a tandem accelerator and 14 C-AMS (Accelerator Mass Spectrometry) dedicated device ( manufactured by NEC Corporation) is attached, and 14 the counting of 13 C, as well as 13 the concentration of12 C), and 14 the concentration of C ( 14 C / 12 C) is measured. From these measured values, the ratio of the C concentration of the sample carbon to the standard modern carbon is calculated. In this measurement, 14 oxalic acid (HOx II) provided by the National Institute of Standards and Technology (NIST), which is a standard sample for C measurement, is used for quantification. 14

[0039] In this embodiment, a sealant film having such a biomass degree is used. And, from the case where all were petroleum-derived resins, in this embodiment, a bio low-density polyethylene resin 10 having properties equivalent to those of petroleum-derived materials is blended (substituted) with the petroleum-derived low-density polyethylene resin 11. As a result, in this embodiment, it is possible to suppress the amount of carbon dioxide emissions derived from petroleum during the production and disposal of the sealant film.

[0040] Furthermore, in this embodiment, as the bio low-density polyethylene resin 10 contained in the resin composition, a plant-derived low-density polyethylene having a density d of 0.910 to 0.925 g / cm 3 and a melt flow rate of 0.5 to 8.0 g / 10 minutes is used. As a result, it is possible to produce a plant-derived sealant film having properties equivalent to those of petroleum-derived materials in an existing film production process. Therefore, the raw material can be switched without impairing the processability of the packaging material. And the plant-derived sealant film according to this embodiment is also equivalent to the petroleum-derived one in terms of durability.

[0041] Furthermore, in this embodiment, since the sealant film has a biomass degree calculated from the measured value of radiocarbon dating 14 C, using this biomass degree as an index, it is possible to identify the raw material origin of the low-density polyethylene resin constituting the sealant film, and to confirm the raw material origin from the time of film production to the time of disposal.

[0042] 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. Further, 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.

[0043] Next, in this embodiment, the above-described bio-low density polyethylene resin 10 and the petroleum-derived low density polyethylene resin 11 can also form a sealant film as follows. That is, the sealant film can be formed in accordance with the following (A) and (B) such that the blending amount of the bio-low density polyethylene resin 10 is 10 to 100 mol% and the blending amount of the petroleum-derived low density polyethylene resin 11 is 0 to 90 mol% with respect to the entire film.

[0044] First, as shown in FIG. 2 described above as the film F1 of (A), it can be a single-layer structure composed of a resin composition in which the bio-low density polyethylene resin 10 and the petroleum-derived low density polyethylene resin 11 are mixed. Here, as described above, the resin composition constituting the film F1 contains 10 to 100 mol% of the bio-low density polyethylene resin 10 and 0 to 90 mol% of the petroleum-derived low density polyethylene resin 11. Therefore, when the content of the petroleum-derived low density polyethylene resin 11 is 0 mol%, the film F1 has a single-layer structure of the bio-low density polyethylene resin 10 alone.

[0045] FIG. 3 is a film having a multilayer structure in which the middle layer is made of the bio-low density polyethylene resin 10 It is a cross-sectional view schematically showing a film. As shown in FIG. 3 as the film F2 of (B), it can also have a multilayer structure including a middle layer made of a resin composition in which a bio-low density polyethylene resin 10 and a petroleum-derived low density polyethylene resin 11 are mixed, an outer layer made of a petroleum-derived low density polyethylene resin 11, and an inner layer. Here, similar to the film F1, the resin composition constituting the middle layer of the film F2 contains 10 to 100 mol% of the bio-low density polyethylene resin 10 and 0 to 90 mol% of the petroleum-derived low density polyethylene resin 11. Therefore, when the content of the petroleum-derived low density polyethylene resin 11 in the middle layer of the film F2 is 0 mol%, the bio-low density polyethylene resin 10 forms a single-layer structure alone.

[0046] With such a configuration, the use ratio of the petroleum-derived raw material of the resin composition constituting the films F1 and F2 can be reduced, and the amount of petroleum-derived carbon dioxide emissions during film production, disposal, etc. can be suppressed. In addition, since the petroleum-derived low density polyethylene resin 11 is used for the inner and outer layers constituting the film F2 as in (B), the film F2 can be manufactured, used, and processed with the same characteristics as existing films. The multilayer film F2 can be manufactured by coextrusion molding.

[0047] Next, in this embodiment, the above-described films F1 and F2 can be used to form a laminated film for packaging materials. FIG. 4 is a cross-sectional view schematically showing an example of a laminated film for packaging materials.

[0048] First, the laminated film 12 for packaging materials has a basic structure in which the above-described films F1 and F2 are laminated with a base film 14 as a sealant film 13. And the laminated film 12 for packaging materials according to this embodiment is radiocarbon dating 14Preferably, it has a biomass degree calculated from the measured value of C of at least 25%. With such a configuration, the usage ratio of the petroleum-derived low-density polyethylene resin 11 that constitutes each of the films F1 and F2 of the sealant film 13 used for heat sealing can be reduced. And the laminated film 12 for packaging materials according to the present embodiment can save petroleum resources and suppress the carbon dioxide emissions derived from petroleum during its production, disposal, etc.

[0049] Here, the Japan Bioplastics Association (JBPA) defines "biomass plastics" as "a polymer material with a molecular weight (Mn) of 1,000 or more obtained by chemically or biologically synthesizing substances derived from renewable organic resources as raw materials (excluding unmodified non-thermoplastic natural organic polymer materials)". And by including 25.0% by weight or more of the biomass-derived component in the biomass plastic or the biomass-derived thermosetting plastic raw material composition, it can be made to conform to the "Biomass Plamarck".

[0050] The laminated film 12 for packaging materials may have an intermediate layer 15. By variously changing the intermediate layer 15, various functions such as gas barrier properties, impact resistance, pinhole resistance, fragrance retention properties, and chemical resistance can be imparted to the laminated film 12 for packaging materials. For example, a barrier material that suppresses the permeation of water vapor and oxygen is used for the intermediate layer 15. As the barrier material, for example, a biaxially oriented polyamide (nylon (ONy: Oriented Nylon)) film as a barrier resin, or a biaxially oriented polyethylene terephthalate (OPET: Oriented PolyEthylene Terephthalate ) film may be used. Further, as the barrier material, for example, a vapor-deposited film in which a vapor-deposited film of silica, aluminum, etc. is formed on the surface of a barrier resin may be used. Further, as the barrier material, for example, a metal foil such as aluminum may be used.

[0051] The intermediate layer 15 is laminated by being adhered to the sealant film 13 by the adhesive layer 16 and to the base film 14 by the adhesive layer 17. The materials of the adhesive layer 16 and the adhesive layer 17 are appropriately selected according to the type of the base material and the adhesion method. Lamination (adhesion ) methods include, for example, the dry lamination method and the melt extrusion lamination method.

[0052] As the materials of the adhesive layer 16 and the adhesive layer 17 that become the laminate adhesive layer in the dry lamination method, there are polyester adhesives, polyether adhesives, etc. From the viewpoint of adhesion strength, it is preferable to use a two-component curable urethane adhesive. On the other hand, as the materials of the adhesive layer 16 and the adhesive layer 17 that become the melt extrusion resin layer in the melt extrusion lamination method, there are polyethylene, polypropylene, etc. From the viewpoint of adhesion to the base material depending on the type of the base material, it is preferable to use low-density polyethylene. Furthermore, the dry lamination method and the melt extrusion lamination method may be used in combination. Surface modification treatments such as corona discharge treatment, ozone treatment, and plasma treatment may be performed on the surface before each layer is adhered, if necessary, to improve adhesion, and furthermore, an anchor coat agent or the like may be applied.

[0053] A printing layer 18 may be formed on any layer constituting the laminated film 12 for packaging materials. Printing of characters, figures, symbols, patterns, etc. is not particularly limited as long as it is a position visible from the outside of the packaging container, and surface printing may be used. In the layer structure illustrated in FIG. 4, the printing layer 18 is formed inside the base film 14. A white underlayer may be provided on the printing layer 18. The printing layer 18 is formed by printing using gravure printing ink or the like by a printing method such as gravure printing, letterpress printing, screen printing, transfer printing, flexographic printing, etc.

[0054] Note that an outer layer (not shown) may be further laminated on the base film 14 of the laminated film 12 for packaging materials.

[0055] Examples of the base film 14 include polyethylene resins, polypropylene resins, cyclic polyolefin resins, polystyrene resins, acrylonitrile-styrene copolymers (AS resins), acrylonitrile-butadiene-styrene copolymers (ABS resins), polyvinyl chloride resins, fluorine resins, poly(meth)acrylic resins, polycarbonate resins, polyester resins such as polyethylene terephthalate and polyethylene naphthalate, polyamide resins such as various nylons, polyimide resins, polyamideimide resins, polyaryl phthalate resins, silicone resins, polysulfone resins, polyphenylene sulfide resins, polyethersulfone resins, polyurethane resins, acetal resins, and various resin films and sheets such as cellulose resins can be used.

[0056] For the base film 14, it is preferable to use biaxially stretched polypropylene film (OPP: Oriented PolyPolypropylene) or biaxially stretched polyethylene terephthalate (OPET). The biaxially stretched polypropylene film is excellent in moisture resistance, water resistance, chemical resistance, etc., has high versatility and is inexpensive. The biaxially stretched polyethylene terephthalate has low hygroscopicity and is excellent in aroma retention in addition to abrasion resistance, heat resistance, water resistance, etc. And the laminated film 12 for packaging materials using these base films 14 has suitable tensile strength, seal strength, and stiffness as a packaging bag, for example, a flexible packaging bag, and shows excellent processability.

[0057] Furthermore, in this embodiment, the raw material of the biaxially stretched polyethylene terephthalate used for the base film 14 may be plant-derived.

[0058] Next, the manufacturing process of the plant-derived base film 14 that constitutes the laminated film 12 for packaging materials according to the present embodiment will be described. FIG. 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 a starting material for the plant-derived polyethylene terephthalate film, that is, the bio-PET film F3 (see FIG. 1). However, the raw material of the bio-PET film F3 according to the present embodiment is not limited to sugarcane, and any plant that is a raw material for manufacturing polyethylene terephthalate resin may be used, and further, any renewable, bio-derived organic resource excluding fossil resources may be used.

[0059] First, bioethylene 3 is obtained by passing through steps S101 and S102 of FIG. 1 described above.

[0060] Bioethylene 3 is oxidized to obtain bioethylene oxide 4 (1,2-epoxyethane) (step S201). Bioethylene oxide 4 can be obtained, for example, by subjecting bioethylene 3 to pressure heating at 1 to 3 MPa and 200 to 300 °C in the presence of a silver catalyst and subjecting it to catalytic gas-phase oxidation with molecular oxygen or a molecular oxygen-containing gas. Bioethylene oxide 4 may also be produced by reacting bioethylene 3 with hydrogen peroxide or a peracid.

[0061] Bioethylene oxide 4 is hydrolyzed under an acid catalyst to obtain bioethylene glycol 5 (MEG: Mono Ethylene Glycol) (ethane-1,2-diol) derived from plants (step S202). Note that the biomass degree of this bio-MEG 5 can be 100%.

[0062] On the other hand, paraxylene 6, which is a secondary product of petroleum, is oxidized and purified to a high purity to obtain purified terephthalic acid (PTA) 7 (step S203).

[0063] Bio-MEG5 and purified terephthalic acid (PTA) 7 are subjected to condensation polymerization to obtain a bio-PET resin 19 containing plant-derived raw materials (step S204). Since 30% of the raw materials of the bio-PET resin 19 are Bio-MEG5 and 70% are purified terephthalic acid (PTA) 7, the biomass content is 30%.

[0064] The bio-PET resin 19 is formed into a film to form a bio-PET film F3 (step S205). Then, the bio-PET film F3 thus obtained is used as needed for the base film 14 constituting the laminated film 12 for packaging materials. As a result, in this embodiment, the use ratio of the petroleum-derived resin in the resin composition used for the laminated film 12 for packaging materials is further reduced, the consumption of petroleum, which is a fossil resource (depletable resource), is further reduced, and the prevention of global warming is contributed to by reducing the amount of carbon dioxide emissions. More specifically, the bio-PET film F3 can reduce about 10% more CO2 than the petroleum-derived PET film throughout the entire life cycle from raw material procurement to disposal.

[0065] Note that since the bio-PET film F3 has 2 carbon atoms derived from Bio-MEG5 and 8 carbon atoms derived from purified terephthalic acid (PTA) 7, the biomass content is 20%. On the other hand, out of the molecular weight of 192 of the PET structural unit, the molecular weight derived from ethylene glycol is 60. Therefore, the biomass content by the weight method is 60 / 192 = 31.25%.

[0066] FIG. 6 is a cross-sectional view schematically showing an example of a packaging bag produced by heat-sealing the laminated film 12 for packaging materials. The laminated film 12 for packaging materials is formed into a bag by heat-sealing (thermocompression bonding) the outer peripheral ends thereof. Here, an example in which the laminated film 12 for packaging materials is composed of two layers, a sealant film 13 and a base film 14, is shown. And here, the illustration about the adhesive layer is abbreviate | omitted.

[0067] One sheet of the laminated film 12 for packaging material is folded, or two sheets of the laminated film 12 for packaging material are overlapped so that the surfaces of the sealant films 13 which form the inner layer of the laminated film 12 for packaging material face each other, and the outer peripheral ends thereof are heat-sealed. As the heat-sealing method bar sealing, rotary roll sealing, belt sealing, impulse sealing, high-frequency sealing, ultrasonic sealing, etc. can be used. Fig. 6 shows an example in which two laminated films 12A and 12B for packaging material are overlapped.

[0068] Heating and pressing are performed from the sides of the base films 14A and 14B which form the outer layers of the two laminated films 12A and 12B for packaging material by a heating roller (not shown) or the like. Then, by heat, the sealant films 13A and 13B are melted, and by pressure, the sealant films 13A and 13B are brought into close contact with each other. Thereby, a seal portion 21 is formed at the outer peripheral ends of the two laminated films 12A and 12B for packaging material.

[0069] Such a seal portion 21 is formed on three sides of, for example, two rectangular laminated films 12A and 12B for packaging material, and the remaining one side is used as the filling port for the contents. Then, by further forming a seal portion 21 on one side after the contents are filled from the filling port, a bagged packaging bag (quadruple-seal bag 20) is formed.

[0070] Fig. 7 is a perspective view showing a quadruple-seal bag 20 as an example of a packaging bag formed using the laminated film 12 for packaging material according to the present embodiment. Thus, a bag for flexible packaging in which a frozen food such as fried fried rice is filled and packaged can be formed by the flexible packaging material composed of the sealant film 13 and the base film 14 according to the present embodiment.

[0071] With such a configuration, the usage ratio of petroleum-derived raw materials in the laminated film 12 for packaging materials that constitutes the packaging bag can be reduced, saving petroleum resources and suppressing the amount of petroleum-derived carbon dioxide emissions during the manufacture and disposal of the packaging bag. In particular, since the flexible packaging bag is easily disposable, according to the laminated film 12 for packaging materials according to this embodiment that reduces the usage amount of petroleum resources and suppresses the amount of petroleum-derived carbon dioxide emissions, it is possible to achieve the effect of providing 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 not inferior to those derived from petroleum. Therefore, according to the configuration according to this embodiment, it is possible to provide a packaging bag that includes the bio-low density polyethylene resin 10 in which petroleum resources are saved and the environmental load is reduced, and that has processability and physical properties, particularly durability, that are not inferior to those of a petroleum-based resin.

[0072] Note that an opening cut line may be provided at the end of the packaging bag or the like by a laser or the like. Furthermore, for the packaging bag according to this embodiment, a one-piece type, a two-piece type spout, a fastener for resealing, or the like can be arbitrarily attached. And, of course, the bio-low density polyethylene resin 10 or the bio-PET resin 19 may be used as these materials.

[0073] In addition to the four-sided seal bag 20 illustrated in FIG. 7, various forms of packaging bags according to the present embodiment can be manufactured by heat-sealing with heat-sealing forms such as side seal type, two-sided seal type, three-sided seal type, envelope sticking seal type, clasp sticking seal type (pillow seal type), pleated seal type, flat bottom seal type, square bottom seal type, and others. Further, in the present embodiment, by using the laminated film 12 for packaging materials as described above, containers including self-standing packaging bags (standing pouches) and the like, tube containers, liquid paper containers, and the like, lid materials for containers, or labels for containers can also be manufactured. Further, the contents of the packaging bag according to the present embodiment are not limited to the exemplified food and beverages, and can accommodate cosmetics, pharmaceuticals, miscellaneous goods, etc., further reducing the usage ratio of petroleum-derived materials and significantly suppressing the carbon dioxide emissions from petroleum-derived materials.

[0074] In the present embodiment, it is preferable that the biomass ratio is 25% or more in the entire packaging material. For this reason, when the bio-PET film F3 with a biomass ratio of 20% is used for the base film 14, a configuration in which the sealant film 13 contains, for example, about 35% of the bio-low density polyethylene resin 10 can be considered. On the other hand, when the biomass ratio of the base film 14 is 0%, the ratio of the bio-low density polyethylene resin 10 in the sealant film 13 is increased to, for example, 70%. In this way, in the present embodiment, the biomass ratio in the entire packaging material is made to be at least 25% or more.

Examples

[0075] Examples are shown below to explain the present disclosure in more detail and specifically. However, the present disclosure is not limited to the following examples.

[0076] [Example 1] (1) Resin composition Low density polyethylene (LC525 manufactured by Nippon Polyethylene Co., Ltd.: density d = 0.923 g / cm 3, 50.0 parts by weight of melt flow rate (MFR) = 3.5 g / 10 min and biomass low-density polyethylene (SEB853 manufactured by Braskem Co., Ltd.: density d = 0.923 g / cm 3 , 50.0 parts by weight of melt flow rate (MFR) = 2.7 g / 10 min were thoroughly kneaded to prepare a resin composition.

[0077] (2) Film Next, using the resin composition prepared in (1), a single-layer film with a thickness of 30 μm according to this example was manufactured using a single-layer upward blown air-cooled inflation coextrusion film-making machine. That is, the single-layer film according to Example 1 is a film F1 containing bio-low-density polyethylene as shown in FIG. 2. Corona discharge surface treatment (hereinafter referred to as corona treatment) was performed on one surface of the manufactured single-layer film.

[0078] (3) Laminate One side of a biaxially stretched nylon 6 film with a thickness of 15 μm was subjected to corona treatment. Using a normal gravure ink composition on the corona-treated surface, after forming a desired printed pattern by the gravure printing method, a two-component curable polyurethane-based laminating adhesive was applied to the entire surface including the printed pattern using the gravure roll coating method to a thickness of 4.0 g / m 2 (in a dry state) to form a laminating adhesive layer. Then, the corona-treated surface of the single-layer film manufactured in (2) was overlapped with the laminating adhesive layer surface facing each other. After that, the two were dry laminated and laminated to manufacture a laminate.

[0079] (4) Flexible packaging product Next, two sheets of the laminate manufactured in (3) were prepared, and the surfaces on the film side of each (2) were overlapped facing each other. Then, the peripheral end portions of the outer periphery were heat-sealed on three sides to form a seal portion 21, and a three-side seal type flexible packaging bag having an opening upward was manufactured. Snack foods were filled and packaged into the three-side seal type flexible packaging bag through the opening, and then the end portion of the opening was heat-sealed to form a seal portion 21 to manufacture a flexible packaging product.

[0080] [Example 2] (1) Resin composition 30.0 parts by weight of low-density polyethylene (LC522 manufactured by Japan Polyethylene Corporation: density d = 0.923 g / cm 3 , melt flow rate (MFR) = 4.0 g / 10 min) and 70.0 parts by weight of biomass low-density polyethylene (SPB681 manufactured by Braskem: density d = 0.922 g / cm 3 , melt flow rate (MFR) = 3.8 g / 10 min) were thoroughly kneaded to prepare a resin composition.

[0081] (2) Film Next, using the resin composition prepared in (1), a single-layer film having a thickness of 50 μm according to this example was produced using a single-layer upward blown air-cooled inflation coextrusion film forming machine. That is, the single-layer film according to Example 2 is a film F1 containing bio-low-density polyethylene as shown in FIG. 2. One surface of the produced single-layer film was subjected to corona treatment.

[0082] (3) Laminate One surface of a biaxially stretched PET film having a thickness of 12 μm was subjected to corona treatment. Using a normal gravure ink composition on the corona-treated surface, after forming a desired printed pattern by the gravure printing method, a two-component curable polyurethane-based laminating adhesive was applied to the entire surface including the printed pattern using the gravure roll coating method to a thickness of 4.0 g / m 2 (in the dry state) to form a laminating adhesive layer. Then, the corona-treated surface of the single-layer film produced in (2) was opposed to the laminating adhesive layer surface and overlapped, and then the two were dry laminated and laminated to produce a laminate.

[0083] (4) Flexible packaging product Next, two sheets of the laminate produced in (3) were prepared, and the surfaces on the film side of each (2) were overlapped with each other facing each other. Then, the end portions around the outer periphery thereof were triple heat-sealed to form a seal portion 21, and a triple-seal type flexible packaging bag having an opening upward was produced. Snack foods were filled and packaged into the triple-seal type flexible packaging bag from its opening, and then the end portion of the opening was heat-sealed to form a seal portion 21 to produce a flexible packaging product.

[0084] [Example 3] (1) Resin composition First, the following resin compositions (a), (b), and (c) were prepared. (a) Resin composition constituting the first layer 100.0 parts by weight of low-density polyethylene (LC522 manufactured by Nippon Polyethylene Co., Ltd.: density d = 0.923 g / cm 3 , melt flow rate (MFR) = 4.0 g / 10 min), 0.5 part by weight of synthetic silica, and 0.05 part by weight of erucic acid amide were sufficiently kneaded to prepare a resin composition. (b) Resin composition constituting the second layer 100.0 parts by weight of biomass low-density polyethylene (SPB681 manufactured by Braskem S.A.: density d = 0.922 g / cm 3 , melt flow rate (MFR) = 3.8 g / 10 min) was prepared. (c) Resin composition constituting the third layer 100.0 parts by weight of low-density polyethylene (LC522 manufactured by Nippon Polyethylene Co., Ltd.: density d = 0.923 g / cm 3 , melt flow rate (MFR) = 4.0 g / 10 min), 0.5 part by weight of synthetic silica, and 0.05 part by weight of erucic acid amide were sufficiently kneaded to prepare a resin composition.

[0085] (2) Film Next, using each resin composition prepared in (1), these were co-extruded using a three-layer upward blowing air-cooled inflation coextrusion film forming machine to form a film such that the layer made of the resin composition in (a) was 10 μm, the layer made of the resin composition in (b) was 30 μm, and the layer made of the resin composition in (c) was 10 μm, respectively, to produce a multilayer laminated film according to this Example which is a coextruded inflation film with a total thickness of 50 μm for 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 as shown in FIG. 3 is bio-low density polyethylene resin 10. Corona treatment was performed on the surface of the first layer (a) of the produced multilayer laminated film.

[0086] (3) Laminate One side of a biaxially stretched PET film with a thickness of 12 μm was subjected to corona treatment. Using a normal gravure ink composition on the corona-treated surface, after forming a desired printed pattern by the gravure printing method, a two-component curable polyurethane-based laminating adhesive was applied to the entire surface including the printed pattern using the gravure roll coating method to a thickness of 4.0 g / m 2 (in the dry state) to form a laminating adhesive layer. Next, the corona-treated surface of the layer made of the resin composition of the first layer (a) of the multilayer laminated resin film produced in (2) was opposed to the laminating adhesive layer surface and overlapped, and then the two were dry laminated and laminated to produce a laminate.

[0087] (4) Flexible packaging product Next, two sheets of the laminate produced in (3) were prepared, and the surfaces of their third layers (c) were opposed and overlapped. Then, the peripheral end portions of the outer periphery were triple heat-sealed to form a seal portion 21, and a triple-seal type flexible packaging bag having an opening upward was produced. Snack foods were filled and packaged into the triple-seal type flexible packaging bag from its opening, and then the end portion of the opening was heat-sealed to form a seal portion 21 to produce a flexible packaging product.

[0088] [Example 4] (1) Resin composition Low-density polyethylene (LC520 manufactured by Japan Polyethylene Corporation: density d = 0.923 g / cm 3 , melt flow rate (MFR) = 3.6 g / 10 min) 30.0 parts by weight, and biomass low-density polyethylene (SEB853 manufactured by Braskem S.A.: density d = 0.923 g / cm 3 , melt flow rate (MFR) = 2.7 g / 10 min) 70.0 parts by weight were thoroughly kneaded to prepare a resin composition.

[0089] (2) Film Next, using the resin composition prepared in (1), a single-layer upward blown air-cooled inflation coextrusion film manufacturing machine was used to manufacture a single-layer film according to this Example with a thickness of 50 μm. That is, the single-layer film according to Example 4 is a film F1 containing bio-low-density polyethylene as shown in FIG. 2. Corona treatment was performed on one surface of the manufactured single-layer film.

[0090] (3) Laminate One surface of a biaxially stretched PET film with a thickness of 12 μm was subjected to corona treatment, and a two-component curable polyurethane-based laminate adhesive was applied to the corona-treated surface to a thickness of 3.0 g / m 2 (in a dry state) to form an adhesive layer. Then, a biaxially stretched PET film with a thickness of 12 μm and corona treatment on both surfaces was superposed on the surface of the adhesive layer. Further, in the same manner as above, a two-component curable polyurethane-based laminate adhesive was applied to the surface of the biaxially stretched PET film with corona treatment on both surfaces laminated above to a thickness of 3.0 g / m 2 (in a dry state) to form an adhesive layer, and a base film 14 was obtained. The surface of the adhesive layer of the base film 14 and the corona-treated surface of the single-layer film manufactured in (2) were opposed and superposed to obtain a multilayer laminated film in which the base film 14 of this Example was laminated.

[0091] (4) Flexible packaging product Next, two sheets of the laminate produced in (3) were prepared, and they were overlapped with the surfaces on the film side of each (2) facing each other. Then, the outer peripheral end portions thereof were heat-sealed on three sides to form a seal portion 21, and a three-side seal type flexible packaging bag having an opening portion upward was produced. Snack foods were filled and packaged into the three-side seal type flexible packaging bag from its opening portion. Then, the end portion of the opening portion was heat-sealed to form a seal portion 21, thereby producing a flexible packaging product.

[0092] [Example 5] (1) Resin composition First, the following resin compositions (a), (b), and (c) were prepared. (a) Resin composition constituting the first layer 100.0 parts by weight of low-density polyethylene (LC522 manufactured by Nippon Polyethylene Co., Ltd.: density d = 0.923 g / cm 3 , melt flow rate (MFR) = 4.0 g / 10 min), 0.5 part by weight of synthetic silica, and 0.05 part by weight of erucic acid amide were sufficiently kneaded to prepare a resin composition. (b) Resin composition constituting the second layer 100.0 parts by weight of biomass low-density polyethylene (SPB681 manufactured by Braskem S.A.: density d = 0.922 g / cm 3 , melt flow rate (MFR) = 3.8 g / 10 min) was prepared. (c) Resin composition constituting the third layer 100.0 parts by weight of low-density polyethylene (LC522 manufactured by Nippon Polyethylene Co., Ltd.: density d = 0.923 g / cm 3 , melt flow rate (MFR) = 4.0 g / 10 min), 0.5 part by weight of synthetic silica, and 0.05 part by weight of erucic acid amide were sufficiently kneaded to prepare a resin composition.

[0093] (2) Film Next, using each of the resin compositions prepared in (1), these were co-extruded using a three-layer upward air-cooled inflation co-extrusion film forming machine to form a film with a layer of the resin composition in (a) being 10 μm, a layer of the resin composition in (b) being 30 μm, and a layer of the resin composition in (c) being 10 μm, respectively, to produce a multilayer laminated film according to this example which is a co-extruded inflation film with a total thickness of 50 μm for 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 a bio-low density polyethylene resin 10 as shown in FIG. 3. Corona treatment was applied to the surface of the first layer (a) of the produced multilayer laminated film.

[0094] (3) Laminate One side of a biaxially stretched PET film with a thickness of 12 μm was subjected to corona treatment, and a two-component curable polyurethane-based laminating adhesive was applied to the corona-treated surface to a thickness of 3.0 g / m 2 (in the dry state) to form an adhesive layer. Then, a biaxially stretched nylon 6 film with a thickness of 15 μm and corona treatment on both sides was overlapped on the surface of the adhesive layer, and further, in the same manner as above, a two-component curable polyurethane-based laminating adhesive was applied to the surface of the biaxially stretched nylon 6 film with corona treatment on both sides laminated above to a thickness of 3.0 g / m 2 (in the dry state) to form an adhesive layer, and a base film 14 was obtained. The surface of the adhesive layer of the base film 14 and the corona-treated surface of the co-extruded multilayer laminated film in (2) were opposed and overlapped to obtain a multilayer laminated film with the base film 14 of this example laminated.

[0095] (4) Flexible packaging product Next, two sheets of the laminate produced in (3) were prepared, and their third layer (c) surfaces were opposed and overlapped. Then, the peripheral ends of the outer periphery were triple heat-sealed to form a seal portion 21 and a triple-seal type flexible packaging bag having an opening upward was produced. Quick-frozen fried rice was filled and packaged into the triple-seal type flexible packaging bag from its opening, and then the end of the opening was heat-sealed to form a seal portion 21 to produce a flexible packaging product.

[0096] [Example 6] (1) Resin composition 20.0 parts by weight of low-density polyethylene (LC525 manufactured by Nippon Polyethylene Co., Ltd.: density d = 0.923 g / cm 3 , melt flow rate (MFR) = 3.5 g / 10 min) and 80.0 parts by weight of biomass low-density polyethylene (SEB853 manufactured by Braskem S.A.: density d = 0.923 g / cm 3 , melt flow rate (MFR) = 2.7 g / 10 min) were thoroughly kneaded to prepare a resin composition.

[0097] (2) Film Next, using each resin composition prepared in (1), a single-layer film having a thickness of 30 μm according to this example was produced using a single-layer upward blown air-cooled inflation coextrusion film forming machine. That is, the single-layer film according to Example 6 is a film F1 containing bio-low-density polyethylene as shown in FIG. 2. Corona treatment was applied to one surface of the produced single-layer film.

[0098] (3) Laminate One surface of a biaxially stretched biomass PET film (bio-PET film F3) having a thickness of 12 μm was subjected to corona treatment. Using a normal gravure ink composition on the corona-treated surface, a desired printed pattern was formed by the gravure printing method. Then, a two-component curable polyurethane-based laminating adhesive was applied to the entire surface including the printed pattern using the gravure roll coating method to a thickness of 4.0 g / m 2 (in the dry state) to form a laminating adhesive layer. Next, the corona-treated surface of the single-layer film produced in (2) was opposed to the laminating adhesive layer surface and laminated, and then the two were dry-laminated and laminated to produce a laminate.

[0099] (4) Flexible packaging product Next, two laminated materials produced in (3) were prepared, and the surfaces on the film side of each of (2) were overlapped with each other facing each other. Then, the end portions around the outer periphery thereof were triple heat-sealed to form a seal portion 21, and a triple-seal type flexible packaging bag having an opening upward was produced. Inside the triple-seal type flexible packaging bag, fried fried rice rapidly frozen from the opening was filled and packaged. Then, the end portion of the opening was heat-sealed to form a seal portion 21 to produce a flexible packaging product.

[0100] As described in detail above, the films F1 and F2 made of the low-density polyethylene resin of the present disclosure are made of a resin composition containing the bio-based low-density polyethylene resin 10 obtained by the high-pressure polymerization method. And these films F1 and F2 are used as the sealant film 13, and are made into the laminated film 12 for packaging materials laminated with the base film 14, and the packaging bag is made of this laminated film 12 for packaging materials.

Industrial Applicability

[0101] The present disclosure can be applied to films made of polyethylene-based resins, and various products using polyethylene-based resins such as packaging bags and containers composed of these films.

Explanation of Signs

[0102] 10 Bio-based 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 Four-side seal bag (packaging bag) F1, F2 Films (sealant films) F3 Bio-PET film

Claims

1. A laminated film for packaging materials, having a base film, an intermediate layer, and a sealant film in this order, wherein the base film is a polypropylene-based resin or a polyester-based resin, the intermediate layer is a vapor-deposited film, the sealant film has an outer layer, a middle layer, and an inner layer, the resins constituting the outer layer and the inner layer are made of petroleum-derived low-density polyethylene resin, the resin composition constituting the middle layer consists of 10 to 80% by weight of a plant-derived high-pressure low-density polyethylene resin and 20 to 90% by weight of a petroleum-derived high-pressure low-density polyethylene resin as resin components, The petroleum-derived high-pressure low-density polyethylene resin has a density d of 0.910 to 0.925 g / cm ３ and a melt flow rate (MFR) of 0.5 to 8.0 g / 10 min, The high-pressure low-density polyethylene resin derived from the plant has a density d of 0.910 to 0.925 g / cm ３ and a melt flow rate (MFR) of 0.7 to 3.8 g / 10 min, The laminated film for packaging materials has a biomass degree calculated from the measured value of radiocarbon dating 14 and has at least 25% of the biomass degree calculated from the measured value of the sealant film does not contain 0.2% by mass or more of silica, 5.0% by mass or more of titanium oxide, an ionomer, and an ethylene-methacrylic acid copolymer, and is a laminated film for packaging materials characterized by this.

2. The laminated film for packaging materials according to Claim 1, characterized in that the plant-derived low-density polyethylene resin has a biomass content of 10 to 100%.

3. The laminated film for packaging materials according to Claim 1 or 2, characterized in that the polyester-based resin 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.

4. A packaging bag characterized by using the laminated film for packaging materials according to any one of Claims 1 to 3. ​ ​

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