Packaging Film

Abstract

To provide a packaging film which facilitates heat seal and is excellent in anti-blocking performance.SOLUTION: A packaging film has one surface formed of ion powder-blended propylene-based resin layer, wherein the one surface is an iron powder-derived rough surface, and surface roughness Sa (ISO25178) of the rough surface is within a range of 1.0 to 10 μm.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a packaging film used for forming bag-shaped containers (pouches) and the like. [Background technology]

[0002] Conventionally, films made of olefin resins such as polypropylene and polyethylene, and polyester resins such as polyethylene terephthalate (PET), etc., have been widely used as packaging films because they can be easily made into bag-shaped containers (pouches) by attaching them by heat sealing. Among them, packaging films made of olefin resins are inexpensive and are widely used, especially as packaging films for food (see Patent Documents 1 and 2).

[0003] Incidentally, with the recent diversification of food products, food-filled pouches are subjected to heat treatment such as microwave heating and retort sterilization, and properties such as impact resistance and heat resistance are required. For this reason, random polypropylene (random PP) and block polypropylene (block PP) have been proposed as heat-sealing resins (sealant resins) to satisfy such requirements (see Patent Documents 3 and 4).

[0004] By the way, although random PP and block PP show high impact resistance, they have problems such as being prone to blocking, whereby the films stick to each other and become difficult to peel off, or the films stick to conveyor belts, etc., which easily cause conveying problems, etc. In addition, when filling a pouch with contents, the inner surfaces of the pouches stick to each other, which causes problems such as clogging and filling problems. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2015-214352 A [Patent Document 2] JP 2020-97421 A [Patent Document 3] WO2017 / 038349 [Patent Document 4] Patent Publication No. 2021-50295 Summary of the Invention [Problem to be solved by the invention]

[0006] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a packaging film which is easy to heat seal and has excellent anti-blocking properties. [Means for solving the problem]

[0007] As a result of investigations into the above-mentioned problems, the present inventors discovered that by blending iron powder used as an oxygen absorber with an olefin-based resin, it is possible to improve not only the oxygen barrier property by oxygen absorption but also the anti-blocking property, and thus completed the present invention.

[0008] According to the present invention, there is provided a packaging film having one surface formed of an iron powder-containing propylene-based resin layer, the one surface being a rough surface derived from the iron powder, and the surface roughness Sa (ISO25178) of the rough surface being in the range of 1.0 to 10 μm. The iron powder-blended propylene-based resin layer contains 0.1 to 10 parts by mass of a metal halide and 0.5 to 2 parts by mass of an alkaline substance per 100 parts by mass of the iron powder. The packaging film is characterized in that

[0009] In the packaging film of the present invention, the following aspects are preferably adopted. (1 )before A propylene-based resin layer not containing iron powder is laminated on the other surface of the propylene-based resin layer containing iron powder, and the exposed surface of the propylene-based resin layer not containing iron powder also reflects the roughness derived from the iron powder, and has a surface roughness Sa (ISO25178) of 1.0 μm or more. ( 2 ) The propylene-based resin layer not containing iron powder has a thickness of 10 to 100 μm. ( 3) A vapor deposition film having a vapor deposition layer is laminated on the surface of the iron powder-containing propylene-based resin layer opposite the rough surface.

[0010] According to the present invention, there is also provided a packaging bag obtained by using a packaging film having the above-mentioned propylene-based resin layer not containing iron powder, in which another packaging film is laminated on the rough surface of the iron powder-containing propylene-based resin layer via a dry laminate adhesive. In such a packaging bag, ( 4 ) the surface of the propylene-based resin layer not containing iron powder is the inner surface that comes into contact with the material to be packaged; ( 5 ) The other packaging film is a polyester film, a polyamide film, or a barrier film having an inorganic vapor deposition layer; is preferred. Effect of the Invention

[0011] The packaging film of the present invention is characterized in that iron powder is blended into the propylene-based resin layer forming one surface, and thus the surface is roughened with a surface roughness Sa (ISO25178) in the range of 1.0 to 10 μm. That is, since at least one surface of the film is roughened with such a surface roughness Sa, blocking between films can be effectively suppressed. For example, as shown in the examples described later, such a rough surface has a small friction coefficient and is slippery, and as a result, anti-blocking properties are expressed.

[0012] In the present invention, the presence of iron powder blended into the propylene-based resin on the surface is reflected in the surface roughness Sa, and the iron powder is used as an oxygen absorber (also called an oxygen scavenger). That is, by blending a small amount of an auxiliary agent (metal halide, alkali compound, etc.) used together with the iron powder in the oxygen absorber in the propylene-based resin layer on the surface, it is possible to impart oxygen absorption properties and exhibit oxygen barrier properties, which is a major advantage of the present invention.

[0013] It is particularly preferable that the above-mentioned packaging film has a two-layer structure in which a propylene-based resin layer not containing iron powder is laminated on the other side of the above-mentioned propylene-based resin layer containing iron powder, whereby the propylene-based resin layer not containing iron powder can be used as a sealant (heat seal layer) to form a packaging bag. In such a packaging bag, another packaging film may be laminated on the rough surface of the iron powder-containing propylene-based resin layer using a dry lamination adhesive. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The packaging film of the present invention has an essential condition that one side thereof is formed of an iron powder-blended propylene-based resin layer. The simplest layer structure is a single layer of iron powder-blended propylene-based resin layer, but it may of course have a multilayer structure in which another resin layer is laminated on the iron powder-blended propylene-based resin layer.

[0015] Iron powder-blended propylene-based resin layer; First, this layer is exposed on at least one surface of the packaging film, and the exposed surface is a rough surface having a surface roughness Sa (ISO25178) in the range of 1.0 to 10 μm, particularly 1.0 to 5.0 μm. Since this surface is rough, the dynamic friction coefficient (μ D ) is small, preferably less than 2.0, more preferably in the range of 0.5 to 1.1, and the packaging film of the present invention has high anti-blocking properties. For example, if the surface roughness Sa is smaller than the above range, the dynamic friction coefficient of the surface increases, and the anti-blocking properties are impaired. On the other hand, if the surface roughness Sa is larger than the above range, problems such as roll winding slippage during film formation and the surface being prone to wrinkles occur.

[0016] The surface roughness Sa is a parameter that expands the line roughness Ra (arithmetic mean height of the line) into three dimensions, and is the average of the absolute values ​​of the differences in height from the average plane of each measurement point in a certain reference area. In the present invention, the surface roughness Sa is used as the roughness parameter instead of the line roughness Ra because there is less variation depending on the measurement area compared to the line roughness Ra.

[0017] The iron powder-blended propylene-based resin layer has the above-mentioned surface roughness Sa, which is derived from the iron powder blended in the layer. Therefore, the resin layer is an unstretched layer or an unstretched film, and is also called a CPP layer or a CPP film. The thickness of the iron powder-blended propylene-based resin layer can be appropriately determined depending on the average particle size and content of the iron powder to be blended or the intended use, but is preferably in the range of 5 to 100 μm.

[0018] The propylene-based resin used in such layers usually has an MFR of extrusion molding grade, and has an MFR of about 1.0 to 50 g / 10 min@230°C. As such polypropylene, any of homopolypropylene (homoPP), random polypropylene (randomPP) and block polypropylene (blockPP) can be used, but since homoPP is unsatisfactory in terms of impact resistance, random PP and block PP, which are excellent in this property, are preferably used in the present invention. Random PP and block PP, which are particularly high in impact resistance, are highly flexible and rubber-like, and therefore prone to blocking, but in the present invention, the anti-blocking property is enhanced by the incorporation of iron powder, and therefore these PPs are preferably used by taking advantage of the advantages of the present invention.

[0019] In the present invention, random PP is a copolymer of polypropylene and a small amount of ethylene, and since it has a large amount of amorphous parts, it has lower rigidity than homo PP, but has excellent impact resistance and flexibility. Random PP is particularly prone to blocking, so it is most suitable for utilizing the advantages of the present invention.

[0020] On the other hand, block PP, also known as impact polypropylene (impact PP), has a structure in which rubber components such as ethylene-propylene copolymer (EPR) or styrene-butadiene copolymer (SBR) are dispersed in a matrix of homo-PP or random PP. The dispersion of these rubber components significantly improves impact resistance and also provides high heat resistance.

[0021] That is, block PP has a structure in which the rubber component is dispersed in islands, and a small amount of modifying resin, such as linear low density polyethylene (LLDPE), may be blended to adjust the physical properties. Such modifying resin is a component that enhances the compatibility between the matrix polypropylene (PP) and ethylene-propylene copolymer (EPR) and greatly improves the dispersibility of EPR in PP, thereby fully demonstrating the impact improvement effect of EPR. In such block PP, the amount of rubber component and modifying resin is adjusted so that the desired physical properties are obtained.

[0022] In addition, in light of the recent increase in environmental awareness, the propylene-based resin used in the iron powder-blended propylene-based resin layer and the iron powder-unblended propylene-based resin layer may be partly or partially made of raw materials that are not only derived from petroleum but also chemically recycled from waste plastics by monomerization techniques such as gasification and oilification, or may be a resin produced from biomass materials derived from plants, etc. The degree of biomass can be measured by measuring the radioactive carbon concentration, etc. Furthermore, when producing propylene-based resins, it is desirable to use a catalyst system that does not use SVHC substances (Substances of Very High Concern under the European Registration, Evaluation, Authorization and Restriction of Chemicals (REACH) regulations) such as phthalate ester compounds at the polymerization stage from the raw materials, in order to reduce the environmental impact. Furthermore, it is also useful from an environmental perspective to blend mechanically recycled materials, which are waste resin generated during packaging manufacturing or commercialized plastic products that have been collected, separated, washed, and re-pelletized, into the propylene-based resin layer.

[0023] In the present invention, iron powder is blended into the propylene-based resin layer as described above, and the rough surface having the above-mentioned surface roughness Sa is formed by this iron powder. That is, in order to obtain the above-mentioned surface roughness Sa, an appropriate amount of iron powder is blended into the propylene-based resin layer according to its particle size. Although not limited thereto, it is preferable that the iron powder is contained in the propylene-based resin layer blended with iron powder in a range of 1 to 40 mass %.

[0024] Iron is a metal that exhibits oxygen absorption (oxygen capture), and can impart oxygen absorption properties and oxygen barrier properties to the iron powder-blended propylene-based resin layer present on the surface of the packaging film.

[0025] Oxygen absorbers containing iron powder are known, for example, from Japanese Patent No. 5378639 and Japanese Patent No. 4893978. 2 / g or more. Examples of such iron powder include reduced iron powder, atomized iron powder, electrolytic iron powder, and carbonyl iron powder, but reduced iron powder is preferably used because of its high oxygen absorption ability. That is, reduced iron powder is obtained by reducing iron ore and has a large specific surface area. In particular, rotary reduced iron powder is particularly preferable because of its high purity. Furthermore, iron powder with a half-width of the peak of the (110) plane of iron measured by powder X-ray diffraction (Co-Kα) of 0.20° / 2θ or less is preferable because it suppresses the generation of hydrogen as a by-product of the oxygen absorption reaction. Such a half-width of the peak of the (110) plane of iron can be adjusted by heat treating the iron under certain conditions.

[0026] When utilizing the oxygen absorbing properties of iron powder, a metal halide or an alkaline compound is used in combination with the iron powder as an auxiliary agent.

[0027] Metal halides function as assistants that promote the oxygen absorption reaction, and are halides of various metals (e.g., alkali metals, alkaline earth metals, copper, zinc, iron, etc.), and examples of such halides include sodium chloride, sodium bromide, sodium iodide, potassium chloride, potassium bromide, potassium iodide, calcium chloride, magnesium chloride, barium chloride, etc. In particular, sodium chloride is most suitable in terms of performance as an assistant and cost.

[0028] Such metal halides may be used in small amounts compared to the iron powder, for example, in an amount of 0.1 to 10 parts by mass, particularly 1 to 5 parts by mass, per 100 parts by mass of iron powder.

[0029] On the other hand, the alkaline compound absorbs water and promotes the oxygen absorption reaction by the iron powder, and examples of the alkaline compound that can be used include magnesium hydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide, magnesium carbonate, calcium carbonate, strontium carbonate, barium carbonate, etc. In particular, non-carbonate compounds are preferred in terms of avoiding foaming, and slaked lime (calcium hydroxide) and quicklime (calcium oxide) are preferably used.

[0030] Such an alkaline compound may be used in a small amount compared to the iron powder, for example, in an amount of 0.5 to 2 parts by mass, particularly 1 to 2 parts by mass, per 100 parts by mass of iron powder.

[0031] The oxygen absorbent containing the above-mentioned iron powder is appropriately pulverized to prepare a mixed powder having an average particle size (median size) of about 1 to 40 μm, which is then dispersed in the above-mentioned olefin resin.

[0032] Various additives can be blended into the above-mentioned iron powder-blended propylene-based resin layer as long as the surface roughness Sa is within a certain range. However, in order to ensure the recyclability of the iron powder, it is preferable not to blend any other additives. Furthermore, in terms of recyclability, it is also preferable to avoid blending any resin other than the propylene-based resin.

[0033] Layer structure of packaging films; The packaging film of the present invention may have various layer structures so long as it has the above-mentioned iron powder-containing propylene-based resin layer on at least one surface.

[0034] For example, the packaging film of the present invention may be a single-layer structure having only the above-mentioned iron powder-containing propylene-based resin layer, i.e., a single-layer film. Both sides of such a single-layer film are roughened with the above-mentioned surface roughness Sa, and the anti-blocking property can be maximized. That is, such a single-layer packaging film can be wound and held on a roll, and when appropriate, the films can be attached to each other by heat sealing to form a bag, and can be used as a bag-shaped container (pouch). Such a bag-shaped container allows the film to be quickly pulled out from the roll, and the bag without contents can be transported without causing transport jams, etc., and is extremely highly productive.

[0035] The single-layer packaging film can also be used as a lid by being attached to the opening of a cup container.

[0036] Furthermore, a single-layer packaging film wound and held on a roll can be pulled out and another resin film or the like can be attached thereto using an epoxy-based or urethane-based dry lamination adhesive to form a multi-layer structure.

[0037] Examples of other resin films that can be attached to the single-layer packaging film using an adhesive include polyester films such as polyethylene terephthalate (PET) and polyamide films such as nylon 6 and nylon 6,6. These films may be stretched to increase their strength. Such multi-layered films with other resins laminated thereon can be used as pouches by heat sealing using the iron powder-blended propylene-based resin layer as a sealant, or as lids for cup-shaped containers. Furthermore, they can be used to mold cup containers by performing thermoforming such as plug-assisted molding and vacuum molding. Furthermore, a PET film (so-called barrier film) on which a vapor deposition layer of silicon oxide or aluminum oxide is formed can be laminated on the single-layer packaging film described above to be used to mold a pouch.

[0038] The single-layer packaging films used for the various applications described above may have any thickness suitable for each application.

[0039] In the present invention, a multilayer film of the above-mentioned iron powder-containing propylene-based resin layer and iron powder-free propylene-based resin layer can be obtained by co-extrusion. Examples of the method for producing such a film include inflation and casting. In particular, the casting method is a suitable method for ensuring the desired surface roughness derived from iron powder. When forming a film from a molten resin from a T-die, the film is cooled by a cooling roll and an air knife, so that the surface shape of one side of the film is restricted by the cooling roll, and the film surface roughness on the opposite side to the air knife side is easily formed to be high.

[0040] The multi-layered packaging film having the propylene-based resin layer not containing iron powder laminated therein can be used as a pouch by heat sealing the propylene-based resin layer not containing iron powder as the inner layer that comes into contact with the contents. Such a pouch has the advantage that the layer containing iron powder does not come into contact with the contents.

[0041] In the present invention, in the packaging film having a multilayer structure as described above, the propylene-based resin used to form the propylene-based resin layer not containing iron powder is not particularly limited, and various polypropylenes can be used, but block PP is most suitable in terms of its particularly high impact resistance and high heat resistance, including retort resistance.

[0042] Furthermore, in the multi-layer structure, it is preferable to make the thickness of the propylene-based resin layer not containing iron powder as thin as possible within a range in which an appropriate heat seal strength is ensured, for example, about 10 to 100 μm. By making the thickness thin in this way, the surface of the propylene-based resin layer not containing iron powder can also be made a rough surface reflecting the roughness due to the iron powder contained in the propylene-based resin layer containing iron powder, and for example, the rough surface can be made to have a surface roughness Sa of 1.0 μm or more, particularly 1.5 μm or more. This allows anti-blocking properties to be expressed on both sides of the packaging film of the multi-layer structure, and not only can blocking between the films be reliably prevented, but also conveying defects can be avoided due to the excellent anti-blocking properties when either side of the film is in contact with a conveying member.

[0043] The packaging film of the present invention is particularly effective for forming a packaging bag using a structure in which a propylene-based resin layer not containing iron powder is laminated on a propylene-based resin layer containing iron powder. That is, since this packaging film has antiblocking properties, operations such as unwinding from a roll can be performed smoothly, and other packaging films can be easily laminated on the rough surface of the propylene-based resin layer containing iron powder using the above-mentioned dry lamination adhesive, and a packaging bag can be easily obtained by bag making (attaching by heat sealing) using such a laminate. Such a packaging bag not only has the properties of other packaging films, such as puncture strength and gas barrier properties, but also allows smooth filling of contents due to the antiblocking properties of the surface of the propylene-based resin layer not containing iron powder on the inside. EXAMPLES

[0044] The invention is illustrated by the following examples. The various measurement methods employed in the following examples are as follows.

[0045] Surface roughness Sa (unit: μm); A sample piece of 10 mm x 10 mm was cut out from the prepared film. The shape of the outer surface of the film was measured using a non-contact surface shape measuring instrument (Zygo). MetroPro (Ver. 9.1.4 64-bit) was used as the application for measurement and image analysis. An area of ​​282 μm × 212 μm was measured, and wavelengths of 1.326 μm or less were cut from the obtained raw data to remove noise, and the measurement data was obtained. The average value was calculated from an N number of 5.

[0046] Dynamic friction coefficient (μ D ); The evaluation was performed using a friction coefficient measuring device (manufactured by Toyo Seiki Co., Ltd.) in accordance with JIS K7125 "Plastics - Films and sheets - Friction coefficient test method." Contact area 40cm 2 The dimensions were (63mm x 63mm) and the load was 200g. The sample was placed on a SUS substrate and the dynamic friction coefficient was measured. A dynamic friction coefficient of less than 2.0 was judged as ◯ since it had good slipperiness. Moreover, a coefficient of dynamic friction of 2.0 or more or blocking without slipping was judged as x.

[0047] Oxygen absorption performance; The prepared film was cut into 3 cm x 4 cm pieces, and 10 pieces were placed in an oxygen-impermeable container with an internal volume of 85 cc [Hiretoflex: HR78-84 manufactured by Toyo Seikan Co., Ltd. (polypropylene / steel foil / polypropylene cup-shaped laminated container)]. 1 cc of distilled water was then added, and the container was heat-sealed in the atmosphere (oxygen concentration 20%) with a polypropylene (inner layer) / aluminum foil / polyester (outer layer) lid. This was stored at 50°C for 24 hours, and the oxygen concentration in the container was measured by gas chromatography. Those with an oxygen concentration below 20% were marked with an ◯, and those that did not change from 20% were marked with an X.

[0048] In the examples, the following iron powders were used: Iron powder; Specific surface area: 1.8m 2 / g Average particle size (D 50 ): 21μm

[0049] <Example 1> A resin pellet was prepared in advance by mixing 29% by weight of the above iron powder with random PP resin (MFR: 1.20 g / 10 min@230°C, melting point: 164°C, impact strength Izod 23°C: 150 J / cm). Using these pellets, a single-layer film with a thickness of 30 μm was produced using a lab-plastic film-making machine (manufactured by Toyo Seiki Co., Ltd.), and the surface roughness Sa and dynamic friction coefficient (μ D ) was sought. The film-forming conditions were an extruder temperature of 210° C. and a T-die temperature of 230° C. The cooling roll temperature was set to 25° C. The measurement results are shown in Table 1.

[0050] The film surface was obviously uneven and had a low coefficient of friction, due to the iron powder that was added to the surface.

[0051] <Example 2> Except for changing the thickness to 50 μm, a single layer film was produced in the same manner as in Example 1. The measurement results are shown in Table 1. As in Example 1, the surface roughness was high and the friction coefficient was low.

[0052] The reason why the surface roughness value was larger than that of Example 1 is presumably due to the significant difference in cooling rate and extensibility between the part inside the film where the iron powder exists and the resin part during film formation. In other words, it is considered that the resin part had higher extensibility than the part where the iron powder exists and was stretched, resulting in a higher roughness value.

[0053] <Example 3> Two extruders were used to produce a coextruded bilayer film, the equipment and extrusion conditions being as described above. One layer was an iron powder-containing layer (thickness 30 μm) formed using the same resin pellets as in Example 1, and the other layer (inner layer) was a propylene-based resin layer (thickness 60 μm) containing no iron powder.

[0054] For the propylene-based resin layer not containing iron powder, random PP (MFR: 1.20 g / 10 min@230° C., melting point: 164° C., impact strength Izod 23° C.: 150 J / cm) was used. The surface roughness Sa and dynamic friction coefficient (μ D ) were calculated and are shown in Table 1.

[0055] The obtained film had a high surface roughness and a low coefficient of friction. This was due to the roughness of the underlying iron-containing metal layer, which is thought to be the effect of iron powder. The reason why the surface roughness value was higher than in Example 1 is thought to be because the resin part was stretched due to the high cooling rate and extensibility, as explained in Example 2.

[0056] <Example 4> A two-layer film was produced in the same manner as in Example 3, except that the thickness of the propylene-based resin layer (inner layer) not containing iron powder was changed to 30 μm. Similarly, the surface roughness Sa and the dynamic friction coefficient (μ D ) were calculated and are shown in Table 1.

[0057] The obtained film had a rough surface and a low coefficient of friction. This was due to the roughness of the underlying iron-containing layer, which is believed to be the effect of iron powder.

[0058] <Comparative Example 1> The same resin as used in Examples 1 to 4, random PP (MFR: 1.20 g / 10 min @ 230 ° C, melting point: 164 ° C, impact strength Izod 23 ° C: 150 J / cm) was used to produce a single layer film of 30 μm using the equipment and film production conditions used in Example 1, and the surface roughness Sa and dynamic friction coefficient (μ D) were calculated and are shown in Table 1. Compared to Example 1, the surface roughness was lower, and the dynamic friction coefficient was high, so that it did not slide on the SUS plate and measurement was impossible.

[0059] <Comparative Example 2> A single-layer film was prepared in the same manner as in Comparative Example 1, except that the film thickness was changed to 60 μm, and the surface roughness Sa and the dynamic friction coefficient (μ D ) were calculated and are shown in Table 1. This single layer film also had a lower surface roughness than Example 1, and the dynamic friction coefficient was high and it did not slide on the SUS plate, making measurement impossible.

[0060] <Comparative Example 3> A coextrusion two-layer film was produced in the same manner as in Example 3, except that the thickness of the random PP was changed to 200 μm. D ) were calculated and are shown in Table 1. This single layer film also had a lower surface roughness than Example 1, and the dynamic friction coefficient was high and it did not slide on the SUS plate, making measurement impossible.

[0061] [Table 1]

Claims

1. A packaging film having one surface formed from an iron powder-blended propylene-based resin layer, the one surface being a rough surface derived from the iron powder, the rough surface having a surface roughness Sa (ISO25178) in the range of 1.0 to 10 μm, and the iron powder-blended propylene-based resin layer containing 0.1 to 10 parts by mass of a metal halide and 0.5 to 2 parts by mass of an alkaline substance per 100 parts by mass of the iron powder.

2. 2. The packaging film according to claim 1, wherein a propylene-based resin layer not containing iron powder is laminated on the other surface of the propylene-based resin layer containing iron powder, and the exposed surface of the propylene-based resin layer not containing iron powder also reflects the roughness derived from the iron powder, forming a rough surface with a surface roughness Sa (ISO 25178) of 1.0 μm or more.

3. 3. The packaging film according to claim 2, wherein the iron powder-free propylene-based resin layer has a thickness of 10 to 100 μm.

4. 3. The packaging film according to claim 1, further comprising a deposition film having a deposition layer laminated on the surface of the iron powder-containing propylene-based resin layer opposite to the rough surface.

5. A packaging bag obtained by using the packaging film according to claim 2, wherein another packaging film is laminated on the rough surface of the iron powder-containing propylene-based resin layer via a dry lamination adhesive.

6. 6. The packaging bag according to claim 5, wherein the surface of the propylene-based resin layer not containing iron powder forms an inner surface that comes into contact with the material to be packaged.

7. 7. The packaging bag according to claim 5 or 6, wherein the other packaging film is a polyester film, a polyamide film or a barrier film having an inorganic vapor deposition layer.

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