Packaging film

Abstract

The present invention provides a packaging film which is easy to heat-seal and has excellent blocking resistance, characterized in that one surface of the packaging film is formed of a propylene-based resin layer containing iron powder, the one surface is a rough surface derived from the iron powder, and the surface roughness Sa (ISO 25178) of the rough surface is in the range of 1.0-10 [mu] m.

Description

TECHNICAL FIELD

[0001] The present application relates to a packaging film for forming a bag-like container (pouch) or the like. BACKGROUND

[0002] In the past, as a packaging film, a bag-like container (pouch) can be easily made by lamination by heat sealing, and therefore a film formed of an olefin-based resin such as polypropylene, polyethylene, a polyester resin typified by polyethylene terephthalate (PET), or the like is widely used. Among them, the packaging film made of an olefin-based resin is inexpensive, and is widely used as a packaging film for food, in particular (see Patent Documents 1 and 2).

[0003] Further, with the diversification of food types in recent years, in the food-filled pouch, a heating treatment such as microwave heating, retort sterilization, or the like is performed, and properties such as impact resistance, heat resistance, and the like are required. Therefore, in order to meet such requirements, as a resin for heat sealing (sealant resin), random polypropylene (random PP), block polypropylene (block PP), or the like has been proposed (see Patent Documents 3 and 4).

[0004] Further, although the random PP and the block PP exhibit high impact resistance, they are prone to blocking, and there are problems that the films are difficult to peel off from each other, or the films are adhered to a conveyor belt or the like, and are prone to conveyance failure or the like. In addition, when filling the contents into the pouch, there are problems that the inner surfaces of the pouches are adhered to each other to cause filling failure due to clogging or the like. PRIOR ART DOCUMENTS PATENT DOCUMENTS

[0005] Patent Document 1: Japanese Patent Application Publication No. 2015-214352 Patent Document 2: Japanese Patent Application Publication No. 2020-97421 Patent Document 3: WO2017 / 038349 Patent Document 4: Japanese Patent Application Publication No. 2021-50295 SUMMARY PROBLEMS TO BE SOLVED BY THE INVENTION

[0006] Therefore, an object of the present application is to provide a packaging film that is easily heat-sealed and has excellent blocking resistance. SOLUTION TO PROBLEM

[0007] The present inventors have conducted research on the above problem, and as a result, have found that by compounding iron powder used as an oxygen absorber in an olefin-based resin, not only oxygen barrier properties due to oxygen absorption can be improved, but also blocking resistance can be improved, thereby completing the present application.

[0008] According to the present application, there is provided a packaging film characterized by a packaging film in which one surface is formed of an iron powder-combined propylene-based resin layer, the one surface being a rough surface derived from the iron powder, and the rough surface having a surface roughness Sa (ISO 25178) in the range of 1.0 to 10 μm.

[0009] In the packaging film of the present application, the following solutions are preferably employed. (1) In the iron powder-combined propylene-based resin layer, a halogenated metal is combined in an amount of 0.1 to 10 parts by mass and an alkaline substance is combined in an amount of 0.5 to 2 parts by mass per 100 parts by mass of the iron powder. (2) On the other surface of the iron powder-combined propylene-based resin layer, an iron powder-uncombined propylene-based resin layer is laminated, and the exposed surface of the iron powder-uncombined propylene-based resin layer is also a rough surface that reflects the roughness derived from the iron powder and has a surface roughness Sa (ISO 25178) of 1.0 μm or more. (3) The iron powder-uncombined propylene-based resin layer has a thickness of 10 to 100 μm. (4) On the surface of the iron powder-combined propylene-based resin layer opposite to the rough surface, a vapor deposition film having a vapor deposition layer is laminated.

[0010] According to the present application, there is also provided a packaging bag obtained using a packaging film provided with the iron powder-uncombined propylene-based resin layer, in which another packaging film is laminated on the rough surface of the iron powder-combined propylene-based resin layer via a dry lamination adhesive. In the packaging bag, the following is preferably employed. (5) The surface of the iron powder-uncombined propylene-based resin layer is an inner surface that comes into contact with a packaged substance. (6) The other packaging film is a polyester film, a polyamide film, or a barrier film having an inorganic vapor deposition layer. Effects of the Invention

[0011] The packaging film of the present application has iron powder combined in the propylene-based resin layer that forms one surface, and is characterized in that the surface is a rough surface having a surface roughness Sa (ISO 25178) in the range of 1.0 to 10 μm. That is, at least one surface of the film is a rough surface having such a surface roughness Sa, and thus the adhesion of the films to each other can be effectively suppressed. For example, as shown in the examples described later, such a rough surface has a small coefficient of friction and becomes a surface that easily slides, and as a result, exhibits anti-adhesion properties.

[0012] In the present application, the surface roughness Sa of the surface reflects the presence of iron powder in the propylene-based resin that is compounded to the surface, which is used as an oxygen absorber (also referred to as a deoxidizer). That is, by compounding a small amount of an auxiliary agent (halogenated metal, alkaline compound, etc.) that is used in conjunction with the iron powder in the oxygen absorber into the propylene-based resin layer of the surface, oxygen absorption properties can be imparted, and the oxygen barrier properties are also a great advantage of the present application.

[0013] The packaging film described above is particularly preferably a double-layer structure in which the propylene-based resin layer in which the iron powder is compounded is laminated with a propylene-based resin layer in which the iron powder is not compounded on the other surface, whereby the propylene-based resin layer in which the iron powder is not compounded can be utilized as a sealant (heat-seal layer) to form a packaging bag. In such a packaging bag, a structure in which another packaging film is laminated on the rough surface of the propylene-based resin layer in which the iron powder is compounded using a dry lamination adhesive can be employed. DETAILED DESCRIPTION

[0014] The packaging film of the present application is necessarily formed with a propylene-based resin layer in which the iron powder is compounded on one surface, and the simplest layer structure is formed with a single layer of the propylene-based resin layer in which the iron powder is compounded, and of course, a multilayer structure in which another resin layer is laminated on the propylene-based resin layer in which the iron powder is compounded can also be employed.

[0015] propylene-based resin layer in which the iron powder is compounded; First, the 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 (ISO 25178) in the range of 1.0 to 10 μm, particularly in the range of 1.0 to 5.0 μm. Because the surface becomes such a rough surface, the dynamic friction coefficient (μ D ) of the surface is small, preferably less than 2.0, and more preferably in the range of 0.5 to 1.1, and the packaging film of the present application has high blocking resistance. For example, when the surface roughness Sa is less than the above range, the dynamic friction coefficient of the surface becomes large, and the blocking resistance is impaired. In addition, when the surface roughness Sa is greater than the above range, problems such as roll winding deviation during film production, and wrinkles on the surface are likely to occur.

[0016] Note that the surface roughness Sa is a parameter obtained by extending the line roughness Ra (arithmetic mean height of a line) in three dimensions, and is the average of the absolute values of the differences in height from the average surface of each measurement point in a certain reference area. In the present application, the surface roughness Sa is used as the parameter of the roughness instead of the line roughness Ra because the deviation based on the measurement area is less compared to the line roughness Ra.

[0017] Further, the propylene-based resin layer in which the iron powder is compounded has a surface roughness Sa as described above, and the surface roughness Sa is derived from the iron powder compounded in the layer. Therefore, the resin layer is an un-stretched layer or an un-stretched film, and is also referred to as a CPP layer or a CPP film. The thickness of the propylene resin layer containing iron powder can be appropriately determined according to the average particle size and content of the iron powder and the intended use, and is preferably within the range of 5 to 100 μm.

[0018] The propylene resin used in this layer typically has an extrusion-grade MFR of approximately 1.0 to 50 g / 10 min at 230°C. Such polypropylene can be any of homopolypropylene (homoPP), random polypropylene (random PP), and segmented polypropylene (block PP). However, homoPP lacks satisfactory impact resistance, so in the present invention, random and block PP, which exhibit excellent properties, are preferably used. Random and block PP, which have high impact resistance, are particularly flexible and rubbery, making them susceptible to blocking. However, in the present invention, the addition of iron powder improves blocking resistance, allowing these PPs to be appropriately used, effectively leveraging the advantages of the present invention.

[0019] In the present invention, random PP is obtained by copolymerizing a small amount of ethylene with polypropylene. It has a large amorphous portion, resulting in lower rigidity than homopolymer PP, but superior impact resistance and flexibility. Random PP is particularly prone to blocking, making it ideal for effectively 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) and styrene-butadiene copolymer (SBR) are dispersed in a matrix of homopolymer PP or random PP. By dispersing such rubber components, the impact strength is significantly improved and high heat resistance is also exhibited.

[0021] In other words, block PP has a structure in which the rubber component is dispersed in islands. However, to adjust the physical properties, a small amount of a modifying resin, such as linear low-density polyethylene (LLDPE), can be added. This modifying resin is used to improve the compatibility between the polypropylene (PP) matrix and the ethylene / propylene copolymer (EPR), significantly increasing the dispersibility of the EPR in the PP and fully utilizing the EPR's impact-improving effect. In this block PP, the amounts of the rubber component and the modifying resin are adjusted to achieve the desired physical properties.

[0022] Furthermore, with today's growing environmental awareness, the acrylic resin used in the acrylic resin layer containing iron powder or the acrylic resin layer not containing iron powder may be partially or partially derived from petroleum, but may also be obtained by chemically recycling waste plastics through monomerization technologies such as gasification and oilification, or may be produced from biomass materials such as plants. Biomass content can be measured by radiocarbon measurement, etc. Further, in the production of the propylene-based resin, in the polymerization stage from the raw material, from the viewpoint of reducing the environmental load, it is desirable to produce the catalyst system without using SVHC substances (Substance of Very High Concern in the Registration, Evaluation, Authorization and Restriction of Chemicals (REACH) regulation) such as phthalate compounds. Further, in the environmental appeal aspect, it is also useful to market-recover, separate, and clean the waste resin generated in the production of the packaging material or the plastic product, and to incorporate the mechanically recycled material after the regranulation into the propylene-based resin layer.

[0023] In the present application, the iron powder is incorporated in the propylene-based resin layer as described above, and the rough surface of the surface roughness Sa described above is formed by the iron powder. That is, in order to obtain the surface roughness Sa as described above, an appropriate amount of the iron powder is incorporated in the propylene-based resin layer according to the particle diameter thereof. It is preferable that the iron powder is contained in the range of 1 to 40 mass% in the propylene-based resin layer in which the iron powder is incorporated, but it is not limited thereto.

[0024] Further, iron is a metal that exhibits oxygen absorption (oxygen trapping), and the propylene-based resin layer in which the iron powder is incorporated, which is present on the surface of the packaging film, exhibits oxygen absorption and imparts oxygen barrier properties.

[0025] The oxygen absorber containing the iron powder is known, for example, by Patent No. 5378639, Patent No. 4893978, and is generally used as a powder having a BET specific surface area of 0.5 m 2 / g or more. As such iron powder, reduced iron powder, atomized iron powder, electrolytic iron powder, carbonyl iron powder, and the like can be exemplified, but in terms of high oxygen absorption capacity, it is preferable to use reduced iron powder. That is, this is because the reduced iron powder is obtained by reducing iron ore, and has a large specific surface area. In particular, among the reduced iron powders, the rotary reduced iron powder is particularly suitable due to high purity. Further, the half-height width of the peak of the (110) plane of iron measured by powder X-ray diffraction (Co-Kα) is 0.20° / 2θ or less, but it is suitable in terms of suppressing the generation of hydrogen as a byproduct of the oxygen absorption reaction. Such half-height width of the peak of the (110) plane of iron can be adjusted by heat-treating the iron under certain conditions.

[0026] Further, in the case of effectively utilizing the oxygen absorption property of the iron powder, a halogenated metal and an alkaline compound are used together with the iron powder as an auxiliary agent.

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

[0028] Such a metal halide is preferably used in a small amount relative 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 the iron powder.

[0029] On the other hand, the alkaline compound is a substance that absorbs water and performs an oxygen absorption reaction based on iron powder, and examples thereof include magnesium hydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide, magnesium carbonate, calcium carbonate, strontium carbonate, barium carbonate, etc. In particular, non-carbonic acid compounds are preferred in order to avoid foaming, and slaked lime (calcium hydroxide) or quicklime (calcium oxide) is preferably used.

[0030] Such a basic compound is preferably used in a smaller amount than 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 the iron powder.

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

[0032] In the above-mentioned propylene resin layer containing iron powder, various additives can be added as long as its surface roughness Sa is within a certain range. However, in order to ensure the recyclability of the iron powder, it is ideal not to add other additives. Moreover, in terms of recyclability, it is preferred to avoid adding resins other than propylene resins.

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

[0034] For example, the packaging film of the present invention can be a single-layer structure, i.e., a single-layer film, comprising only the aforementioned propylene resin layer containing the iron powder. Such a single-layer film has both sides having a rough surface having the aforementioned surface roughness Sa, maximizing its anti-blocking properties. Specifically, the single-layer packaging film is wound and held on a roll, and when appropriate, the films are bonded together by heat sealing to form a bag, which can be provided as a bag-shaped container (pouch). Such a bag-shaped container allows the film to be quickly pulled from the roll, and unfilled bags can be transported without causing transport blockages, resulting in extremely high productivity.

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

[0036] Further, the single-layer packaging film wound around the roll can be pulled out and attached to another resin film or the like using an epoxy-based or polyurethane-based dry lamination adhesive to form a multilayer structure.

[0037] As the other resin film to be attached to the single-layer packaging film using an adhesive, a polyester film such as polyethylene terephthalate (PET), a polyamide film such as 6 nylon and 6, 6 nylon can be cited. These films can also be stretched to be high-strength. The multilayer structure film in which such other resin is laminated can be used by forming a pouch by heat sealing of the above-mentioned propylene-based resin layer with iron powder incorporated as a sealing agent, or can be used as a lid for a cup container. Further, it can also be subjected to heat forming such as plug assist forming and vacuum forming to be used for forming of a cup container. Further, a PET film formed with a vapor-deposited layer of silicon oxide or aluminum oxide (so-called barrier film) can also be laminated to the above-mentioned single-layer packaging film to be used for forming of a pouch.

[0038] The single-layer packaging film to be used for the above-mentioned various uses can have a thickness suitable for each use.

[0039] Further, in the present application, a multilayer structure film of the above-mentioned propylene-based resin layer with iron powder incorporated and the propylene-based resin layer without iron powder incorporated can be produced by co-extrusion. As the production method of such a film, a blown film method, a cast method and the like can be cited. In particular, in order to ensure the surface roughness derived from the iron powder as the object, the cast method is a suitable production method. When a molten resin is film-formed by a T-die, the film is cooled by a chill roll and an air knife, whereby the surface shape of one side of the film is restricted by the chill roll and the surface roughness of the opposite side of the film on the air knife side is easily formed to be high.

[0040] In the multilayer structure packaging film in which the propylene-based resin layer without iron powder incorporated is laminated, the propylene-based resin layer without iron powder incorporated can be used as the inner layer on the side in contact with the content by heat sealing to be used as a pouch. Such a pouch has the advantage that the layer with iron powder incorporated is not in contact with the content.

[0041] In the present application, in the multilayer structure packaging film as described above, the propylene-based resin used in the formation of the propylene-based resin layer without iron powder incorporated is not particularly limited and various polypropylenes can be used, and in particular, block PP is the most suitable in terms of high impact resistance and high heat resistance such as boiling resistance.

[0042] Further, in the multilayer 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 that ensures a moderate heat seal strength, for example, preferably to a thickness of about 10 to 100 μm. By making it thin in this way, the surface of the propylene-based resin layer not containing iron powder can also serve as a rough surface that reflects the roughness caused by the iron powder incorporated into the propylene-based resin layer containing iron powder, for example, as a rough surface that has a surface roughness Sa of 1.0 μm or more, particularly 1.5 μm or more. Thus, the two surfaces of the packaging film of the multilayer structure can exhibit anti-blocking properties, not only reliably preventing blocking of the films with each other, but also avoiding poor conveyance by excellent anti-blocking properties when either surface of the film comes into contact with a conveyance member.

[0043] The packaging film of the present application is particularly effective in the use of forming a packaging bag using a packaging film having a structure in which a propylene-based resin layer not containing iron powder is laminated to a propylene-based resin layer containing iron powder. That is, the packaging film has anti-blocking properties, so that it can smoothly perform an operation such as unwinding from a roll, can easily laminate another packaging film on a rough surface of the propylene-based resin layer containing iron powder using the dry lamination adhesive described above, and can easily obtain a packaging bag by bag-making (adhesion based on heat sealing) using such a laminate. Such a packaging bag is not only endowed with characteristics possessed by other packaging films, such as puncture strength, gas barrier properties, and the like, but also can smoothly perform a filling operation of contents and the like by the anti-blocking properties exhibited by the surface of the propylene-based resin layer not containing iron powder on the inner surface. Example

[0044] The present application is described below by way of examples. The various measurement methods used in the following examples are described below.

[0045] Surface roughness Sa (unit: μm); A 10 mm x 10 mm sample piece was cut from the produced film. The shape of the outer surface of the film was measured using a non-contact surface shape measuring machine (manufactured by zygo). In the measurement and image analysis, MetroPro (Ver. 9.1.464-bit) was used as an application program. A range of 282 μm x 212 μm was measured, and wavelengths of 1.326 μm or less were cut from the obtained raw data as measurement data for denoising. The average was calculated from N numbers = 5.

[0046] Dynamic friction coefficient (μ D ); Evaluation was performed using a friction coefficient measuring machine (manufactured by Toyo Seiki) according to JIS K7125 "Plastics - Films and sheets - Determination of friction coefficient". The contact area was set to 40 cm 2 (63 mm x 63 mm) and the load was set to 200 g, a sample was provided on a SUS substrate, and the dynamic friction coefficient was measured. A sample having a dynamic friction coefficient of less than 2.0 was good in sliding property, and thus was determined as O. Further, a sample having a dynamic friction coefficient of 2.0 or more or exhibiting adhesion and not sliding was determined as X.

[0047] oxygen absorption performance; The produced film was cut into pieces of 3 cm x 4 cm, 10 pieces were loaded into an oxygen-impermeable container [High-flex: HR78-84, made by Toyo Kan, (polypropylene / steel foil / polypropylene cup-shaped laminated container)] having an inner volume of 85 cc, 1 cc of distilled water was further loaded, and heat-sealing was performed with a lid material of polypropylene (inner layer) / aluminum foil / polyester (outer layer) in an atmosphere (oxygen concentration: 20%). This was stored at 50°C for 24 hours, and the oxygen concentration in the container was measured by gas chromatography. A sample having an oxygen concentration of less than 20% was set as O, and a sample not exhibiting a change at 20% was set as X.

[0048] Further, the following iron powder was used in the examples. iron powder; Specific surface area: 1.8 m 2 / g. Average particle diameter (D 50 ): 21 μm.

[0049] <Example 1> For a random PP (MFR: 1.20 g / 10 minutes at 230°C, melting point: 164°C, Izod impact strength at 23°C: 150 J / cm) resin, resin particles in which 29% by weight of the above iron powder was compounded were prepared in advance. Using the particles, a single-layer film having a thickness of 30 μm was produced by a LABO PLASTOMILL film producing machine (made by Toyo Seiki), and the surface roughness Sa and the dynamic friction coefficient (μ D ) were calculated. The film producing 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 had a clear concave-convex, and the friction coefficient was also low. This is because the iron powder was compounded, and thus the surface was roughened.

[0051] <Example 2> A single layer film was produced in the same manner as in Example 1 except that the thickness was changed to 50 μm. The results of the measurement are shown in Table 1. The surface roughness was coarse and the coefficient of friction was low as in Example 1.

[0052] As a reason why the value of the surface roughness was larger than in Example 1, it is presumed that the difference in the cooling speed and the stretchability of the portion where the iron powder was present and the resin portion inside the film at the time of film production had a significant influence. That is, it is considered that the resin portion was stretched because of its high stretchability compared to the portion where the iron powder was present, and thus the value of the roughness became high.

[0053] <Example 3> A double layer film was produced by co-extrusion using two extruders. The equipment and the extrusion conditions used were as described above. One layer was set to be a layer where the iron powder was compounded (thickness: 30 μm) using the same resin pellets as in Example 1, and the other layer (inner layer) was set to be a propylene-based resin layer (thickness: 60 μm) where the iron powder was not compounded.

[0054] Note that a random PP (MFR: 1.20 g / 10 minutes at 230°C, melting point: 164°C, Izod impact strength at 23°C: 150 J / cm) was used in the propylene-based resin layer where the iron powder was not compounded. As for the inner layer surface of the obtained double layer film, the surface roughness Sa and the dynamic coefficient of friction (μ D ) of the propylene-based resin layer where the iron powder was not compounded were calculated and shown in Table 1.

[0055] The surface roughness of the obtained film was coarse and the coefficient of friction was low. This is because the roughness of the metal iron-containing layer as a base was significantly reflected, and it is considered to be based on the influence of the iron powder. As a reason why the value of the surface roughness was larger than in Example 1, it is considered that the resin portion was stretched because of its high cooling speed and stretchability as explained in Example 2.

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

[0057] The surface roughness of the obtained film was coarse and the coefficient of friction was low. This is because the roughness of the metal iron-containing layer as a base was significantly reflected, and it is considered to be based on the influence of the iron powder.

[0058] <Comparative Example 1> A single layer film of 30 μm was produced from the same random PP (MFR: 1.20 g / 10 min @ 230°C, melting point: 164°C, Izod impact strength 23°C: 150 J / cm) as used in Examples 1 to 4 by using the same apparatus and film production conditions as in Example 1, and the surface roughness Sa and kinetic friction coefficient (μ D ) were measured and are shown in Table 1. The surface roughness was low and the kinetic friction coefficient was high compared with Example 1, and the film did not slide on the SUS plate and could not be measured.

[0059] [Comparative Example 2] A single layer film was produced 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 kinetic friction coefficient (μ D ) were measured and are shown in Table 1. The surface roughness was low and the kinetic friction coefficient was high compared with Example 1, and the film did not slide on the SUS plate and could not be measured.

[0060] [Comparative Example 3] A double layer film was produced by co-extrusion in the same manner as in Example 3, except that the thickness of the random PP was changed to 200 μm. The surface roughness Sa and kinetic friction coefficient (μ D ) of the propylene-based resin layer without the iron powder were measured and are shown in Table 1. The surface roughness was low and the kinetic friction coefficient was high compared with Example 1, and the film did not slide on the SUS plate and could not be measured.

[0061] [Table 1]

Claims

1. A packaging film, characterized in that It is a packaging film with a propylene resin layer containing iron powder on the surface. The one surface is a rough surface derived from iron powder, and the surface roughness Sa of the rough surface according to ISO 25178 is within a range of 1.0 to 10 μm.

2. The packaging film according to claim 1, wherein In the iron powder-blended propylene resin layer, 0.1 to 10 parts by mass of the metal halide and 0.5 to 2 parts by mass of the alkaline substance are blended per 100 parts by mass of the iron powder.

3. The packaging film according to claim 1 or 2, wherein A propylene resin layer without iron powder is laminated on the other surface of the propylene resin layer with iron powder, and the exposed surface of the propylene resin layer without iron powder is also a rough surface reflecting the roughness derived from the iron powder and having a surface roughness Sa of 1.0 μm or more according to ISO25178.

4. The packaging film according to claim 3, wherein The propylene resin layer not containing iron powder has a thickness of 10 to 100 μm.

5. The packaging film according to claim 1 or 2, wherein A vapor-deposited film having a vapor-deposited layer is laminated on the surface of the iron powder-blended acrylic resin layer opposite to the rough surface.

6. A packaging bag obtained by using the packaging film according to claim 4, wherein Another packaging film is laminated on the rough surface of the iron powder-blended acrylic resin layer via a dry lamination adhesive.

7. The packaging bag according to claim 6, wherein: The surface of the propylene resin layer not mixed with iron powder is the inner surface in contact with the packaged substance.

8. The packaging bag according to claim 6 or 7, wherein: Other packaging films are polyester films, polyamide films or barrier films with an inorganic vapor-deposited layer.

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