JP7210685B2 - Packing films and packing materials - Google Patents

Description

TECHNICAL FIELD The present invention relates to a packing film and a packing member for packing articles.

When packing and transporting items in a packaging container such as a cardboard box, in order to prevent the item from being shaken inside the packaging container and colliding with the packaging container during transportation, it is necessary to maintain a gap between the packaging container and the item. may be filled with cushioning material. As the cushioning material, for example, a cushioning material made of foamed resin, a cushioning material made of a molding of a resin film in which air is sealed, and the like can be mentioned.
However, the cushioning material must be discarded by the person who receives the article, and the cushioning material is bulky, so there is a problem that the volume of the waste is large.
Therefore, a method of packing an article in a packing container without using the cushioning material has been proposed. For example, Patent Literature 1 describes a method of sandwiching an article to be transported inside a packaging container with stretchable elastic films attached to the packaging container.
However, in the method described in Patent Document 1, the elastic film sandwiching the article may break during transportation, making it impossible to hold the article.
In Patent Document 2, a substrate such as paper and an elastic polyolefin film are provided, and the polyolefin film leaves a part of the substrate so that an article can be inserted between the substrate and the polyolefin film. A packaging member is disclosed which is heat-sealed to the.

Japanese Patent Application Laid-Open No. 2002-087469 JP 2016-22958 A

However, when the polyolefin film described in Patent Document 2 is wound into a roll, the films adhere to each other, causing a problem called blocking, which makes unwinding difficult.
SUMMARY OF THE INVENTION An object of the present invention is to provide a packing film which has sufficient stretchability, is highly capable of holding articles, and prevents blocking when rolled. SUMMARY OF THE INVENTION An object of the present invention is to provide a packing member that is highly capable of holding an article.

The present invention includes the following aspects.
[1] One outer layer, the other outer layer, and an intermediate layer provided between the one outer layer and the other outer layer, wherein at least one of the one outer layer and the other outer layer has a density is 0.87 g/cm ³ or more, and the polymer contained in at least one of the one outer layer and the other outer layer is homopolypropylene or random polypropylene containing ethylene units in a proportion of 5% by mass or less. A packaging film comprising a rubber component in a matrix and said intermediate layer comprising a thermoplastic elastomer.
[2] The packaging film according to [1], wherein the one outer layer has a thickness of 3 to 10 μm, the other outer layer has a thickness of 1 to 10 μm, and the intermediate layer has a thickness of 20 to 50 μm.
[3] A packaging member comprising the packaging film according to [1] or [2] and a substrate to which the packaging film is attached.

The packaging film of the present invention has sufficient stretchability to hold articles well, prevents deformation of the film during thermal welding, and prevents blocking when formed into a roll.
The packing member of the present invention has high holding properties for articles and prevents deformation of the packing film.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows one Embodiment of the film for packaging of this invention. It is a sectional view showing one embodiment of a member for packing of the present invention.

<Packing film>
One aspect of the packing film of the present invention will be described.
The packaging film of this aspect includes a first outer layer, a second outer layer, and an intermediate layer provided between the first outer layer and the second outer layer. The first outer layer, the second outer layer and the intermediate layer each contain a polymer, and the polymer contained in the second outer layer has a density of 0.87 g/cm ³ or more.
In the packaging film of this aspect, the second outer layer is heat-sealed to a base material described below to form a packaging member.

FIG. 1 shows one embodiment of the packaging film of this aspect. The packaging film 10 of this embodiment is a multilayer film comprising a first outer layer 11 , a second outer layer 12 and an intermediate layer 13 . The intermediate layer 13 is provided between the first outer layer 11 and the second outer layer 12 .

The first outer layer 11 is a layer containing polymer as a main component.
Examples of the polymer contained in the first outer layer 11 include homopolypropylene, random polypropylene, and block polypropylene. Among these polymers, random polypropylene is preferred because of its superior flexibility and high melting point.

The first outer layer 11 contains a polymer having a melting point _Tm1 .
The melting point _Tm2 of the polymer contained in the second outer layer 12, which will be described later, is preferably 120° C. or lower. Practically, the melting point _Tm1 is preferably 80° C. or higher.
In the case of random polypropylene, the melting point can be adjusted by adjusting the content of ethylene units. The higher the ethylene unit content in random polypropylene, the lower the melting point tends to be.
In the present invention, the melting point of a polymer is a value determined by differential scanning calorimetry.

The number of polymers contained in the first outer layer 11 may be one, or two or more. When two or more kinds of polymers are contained in the first outer layer 11, other polymers other than the polymer having the melting point _Tm1 may be contained within a range that does not impair the physical properties of the packaging film 10, particularly stretchability. However, in order to obtain the desired performance, the other polymer is preferably a polyolefin such as polyethylene or polypropylene.

The content of the polymer contained in the first outer layer 11 is preferably 70 to 100% by mass, more preferably 90 to 100% by mass, even more preferably 95 to 100% by mass. If the content of the polymer contained in the first outer layer 11 is at least the lower limit, the heat resistance of the packaging film 10 will be sufficiently high.
In particular, in the first outer layer 11, the content of the polymer having the melting point T _m1 is preferably 70 to 100% by mass, more preferably 90 to 100% by mass, and 95 to 100% by mass. is more preferred.

In the first outer layer 11, if necessary, antioxidants, weather stabilizers, antistatic agents, antifogging agents, metallic soaps, waxes, antifungal agents, antibacterial agents, and nucleating agents are added as components other than the polymer. , flame retardants, and slip agents.

The thickness of the first outer layer 11 is preferably 3-10 μm, more preferably 3-6 μm. When the thickness of the first outer layer 11 is at least the above lower limit, the heat resistance of the packaging film 10 is improved, and the packaging film 10 can be prevented from melting during thermal welding to the substrate. If the thickness of the first outer layer 11 is equal to or less than the upper limit value, the elasticity of the packaging film 10 can be sufficiently ensured, and when the packaging film 10 is used as a packaging member, the holding property of the article is further improved. can be made
In the present invention, the layer thickness is a value obtained by observing the cross section of the packing film 10 using an optical microscope or an electron microscope, measuring the thickness at five or more points, and averaging the thicknesses.

The second outer layer 12 is a layer containing polymer as a main component. The second outer layer 12 contains a polymer with a density of 0.87 g/cm ³ or more, and preferably contains a polymer with a density of 0.88 g/cm ³ or more. When the density of the polymer contained in the second outer layer 12 is equal to or higher than the above lower limit, the stickiness of the surface of the second outer layer 12 can be suppressed, and blocking can be prevented when the packaging film 10 is rolled. The density of the polymer contained in the second outer layer 12 is preferably 0.91 g/cm ³ or less for practical use of the packaging film 10 .

Examples of polymers contained in the second outer layer 12 include block polypropylene, low density polyethylene (LDPE), linear low density polyethylene (LLDPE), high density polyethylene (HDPE), and ethylene-vinyl acetate copolymer (EVA). , ethylene-ethyl acrylate copolymer (EEA), and the like. Among these polymers, block polypropylene is preferable because of its excellent stretchability and flexibility. Here, block polypropylene is a mixture in which a rubber component is contained in a matrix of homopolypropylene or random polypropylene containing 5% by mass or less of ethylene units. Examples of rubber components include ethylene-propylene copolymers, ethylene-butene copolymers, ethylene-hexene copolymers, ethylene-octene copolymers, propylene-butene copolymers, propylene-hexene copolymers, propylene - octene copolymer and the like.
Generally, block polypropylene forms a matrix homopolypropylene or random polypropylene in the first-stage polymerization, and forms a rubber component in the second-stage polymerization in the presence of the homopropylene or random polypropylene. By forming the rubber component in the matrix by polymerization in this way, the dispersibility of the rubber component can be improved.

The number of polymers contained in the second outer layer 12 may be one, or two or more. When two or more types of polymers are contained in the second outer layer 12, other polymers other than the polymer having the above-described density may be contained within a range that does not impair the physical properties of the packaging film 10, particularly stretchability. However, in order to obtain the desired performance, the other polymer is preferably a polyolefin such as polyethylene or polypropylene.

The content of the polymer contained in the second outer layer 12 is preferably 70 to 100% by mass, more preferably 90 to 100% by mass, even more preferably 95 to 100% by mass. If the content of the polymer contained in the second outer layer 12 is at least the lower limit, the stretchability of the packaging film 10 will be sufficiently high.
In particular, in the second outer layer 12, the content of the polymer having a density of 0.87 g/cm ³ or more is preferably 70 to 100% by mass, more preferably 90 to 100% by mass, and more preferably 95 to 100% by mass. % is more preferred.

The second outer layer 12 may optionally contain various additives as components other than the polymer. As the additive, the same additives as those that may be contained in the first outer layer 11 can be used.
In particular, the second outer layer 12 preferably contains a slip agent in order to further prevent blocking. Among the slip agents, organic slip agents are preferred, and amide-based slip agents are more preferred, because of their particularly excellent anti-blocking properties. Examples of amide-based slip agents include erucamide and stearamide, with erucamide being preferred.

The thickness of the second outer layer 12 is preferably 1-10 μm, more preferably 2-6 μm. If the thickness of the second outer layer 12 is equal to or greater than the lower limit, it is possible to further prevent blocking when the packaging film 10 is rolled. If the thickness of the second outer layer 12 is equal to or less than the upper limit, the heat-welding property to the base material, especially the paper base material can be further improved.

The intermediate layer 13 is a layer containing a thermoplastic elastomer as a main component. A thermoplastic elastomer is a thermoplastic resin having rubber elasticity at room temperature.
Examples of thermoplastic elastomers include olefin-based thermoplastic elastomers, styrene-based thermoplastic elastomers, and polyester-based thermoplastic elastomers. Among these elastomers, olefinic thermoplastic elastomers are preferable because they have good adhesion to the first outer layer 11 and the second outer layer 12 .
Examples of olefinic thermoplastic elastomers include ethylene-αolefin copolymers. Examples of α-olefins constituting the ethylene-α-olefin copolymer include propylene, 1-butene, 1-hexene, and 1-octene. The ethylene-α-olefin copolymer may be a random copolymer or a block copolymer, preferably a block copolymer.

The thermoplastic elastomer contained in the intermediate layer 13 may be one kind, or two or more kinds. Further, the intermediate layer 13 may contain a polymer other than the thermoplastic elastomer as long as it does not impair the physical properties of the packaging film 10, especially its stretchability. However, in order to obtain the desired performance, the other polymer is preferably a polyolefin such as polyethylene or polypropylene.

The content of the thermoplastic elastomer contained in the intermediate layer 13 is preferably 70-100% by mass, more preferably 90-100% by mass, even more preferably 95-100% by mass. If the content of the thermoplastic elastomer contained in the intermediate layer 13 is at least the lower limit, the stretchability of the packaging film 10 will be sufficiently high.

The intermediate layer 13 may optionally contain various additives as components other than the thermoplastic elastomer. As the additive, the same additives as those that may be contained in the first outer layer 11 can be used.

The thickness of the intermediate layer 13 is preferably 20-50 μm, more preferably 25-40 μm. If the thickness of the intermediate layer 13 is at least the lower limit value, the elasticity of the packaging film 10 can be sufficiently ensured, and when the packaging film 10 is used as a packaging member, the holding property of the article is further improved. be able to. If the thickness of the intermediate layer 13 is equal to or less than the above upper limit, the article can be held with an appropriate holding force that is not too strong when the packing film 10 is used as a packing member.

The packaging film 10 may be an unstretched film or a stretched film. Stretching the packaging film 10 facilitates adjustment of the film's mechanical properties, particularly shrinkage stress and permanent set.
When the packaging film 10 is a stretched film, it may be a uniaxially stretched film or a biaxially stretched film.

The surface of the packaging film 10, that is, the outer surface of the first outer layer 11 and the outer surface of the second outer layer 12 may be embossed to form irregularities. When the surface of the packaging film 10 is embossed, the slipperiness increases, and blocking of the packaging film 10 can be further prevented.
The embossing may be formed only on the outer surface of the first outer layer 11, may be formed on the outer surface of the second outer layer 12, or may be formed on both the outer surface of the first outer layer 11 and the outer surface of the second outer layer 12. may be

The packaging film 10 is manufactured, for example, by the following method.
A resin material for forming the first outer layer is prepared by mixing a polymer for forming the first outer layer 11 and optional additives. When the optional additive is not included, the resin material for forming the first outer layer consists only of the polymer.
A polymer for forming the second outer layer 12 and optional additives are mixed to prepare a resin material for forming the second outer layer. When the optional additive is not included, the resin material for forming the second outer layer consists only of the polymer.
A resin material for forming an intermediate layer is prepared by mixing a thermoplastic elastomer for forming the intermediate layer 13 and optional additives. When the optional additive is not included, the intermediate layer-forming resin material consists only of the thermoplastic elastomer.
In each resin material, when additives are mixed, a master batch containing the additives and the diluent resin may be mixed with the polymer or thermoplastic elastomer. For example, if the second outer layer contains a slip agent, the polymer may be mixed with a masterbatch containing the slip agent and the diluent resin when obtaining the resin material for forming the second outer layer. By applying a mixing method using a masterbatch, it is possible to easily improve the dispersibility of the additive in the polymer or thermoplastic elastomer.
Next, the resin material for forming the first outer layer, the resin material for forming the second outer layer, and the resin material for forming the intermediate layer are supplied to an extruder capable of multi-layer molding, and each resin material is extruded, and the first outer layer 11 and the It laminates|stacks so that the intermediate|middle layer 13 may be arrange|positioned between the 2nd outer layers 12. As shown in FIG. Extruders capable of multi-layer molding include, for example, those with a multi-manifold die or feedblock system at the tip of the extruder.
A three-layer laminate in a molten state formed by an extruder is brought into close contact with the peripheral surface of a cast roll and cooled to obtain the packaging film 10 . The productivity of the packaging film 10 can be easily improved by applying the casting method of forming the film using a cast roll.

When the surface of the packaging film 10 is embossed, the surface of the packaging film 10 may be brought into close contact with the peripheral surface of an embossing roll having irregularities on the peripheral surface before or after the cooling. The embossing roll may be a cast roll or a heated pinch roll.
The packaging film 10 may be stretched as required. Examples of the method of stretching the packaging film 10 include a method of stretching the film using rolls, a method of stretching the film by gripping the film with a clip, and a method of stretching the film by sandwiching it between a pair of gears. . Among the above stretching methods, the method of stretching the film while sandwiching it between a pair of gears is preferable from the viewpoint of easily increasing productivity.

In addition, the method of manufacturing the packaging film 10 is not limited to the manufacturing method described above. For example, in the manufacturing method, the packaging film 10 may be obtained by inflation-molding a three-layer laminate in a molten state formed by an extruder.

Since the first outer layer 11 and the second outer layer 12 contain a polymer, and the intermediate layer 13 contains a thermoplastic elastomer, the packing film 10 of the present embodiment has high stretchability and is hard to break. Therefore, when an article is packed with the packing film 10 of the present embodiment, the holding property of the article can be sufficiently enhanced.
In the packaging film 10 of the present embodiment, the second outer layer 12 contains a polymer having a density of 0.87 g/cm ³ or more, so the surface adhesive force of the second outer layer 12 is suppressed. Therefore, in the roll-shaped packing film 10, the first outer layer 11 can be easily peeled off from the second outer layer 12 from the state in which the first outer layer 11 and the second outer layer 12 are in close contact, preventing blocking. can.

<Packing material>
One aspect of the packing member of the present invention will be described.
A packaging member of this aspect includes the packaging film of the above-described embodiment and a substrate to which the second outer layer of the packaging film is heat-sealed.
Examples of base materials include paper base materials, resin sheets, non-woven fabrics, and the like. Among the substrates, paper substrates are preferable, and among paper substrates, corrugated board or thick paper is more preferable, and corrugated board is even more preferable, from the viewpoint of strength.
The shape of the substrate is not particularly limited, and may be appropriately selected according to the shape of the article to be packed and the shape of the packing container. Examples of the shape of the substrate include rectangular, square, circular, elliptical, and the like.

Examples of the method for producing the packing member of this aspect include the following methods.
First, the packaging film is overlaid on the substrate so that the second outer layer is in contact with the substrate. Next, a heated heat seal bar is pressed against the peripheral portion of the packaging film to thermally weld the peripheral portion of the packaging film to the substrate. At that time, the entire peripheral edge of the packaging film is not heat-sealed to the substrate so that the article can be inserted between the substrate and the packaging film, and a part of the peripheral edge of the packaging film is not attached to the substrate. The part is left unattached without heat welding. A packing member can be obtained by heat-sealing as described above.
The heat-sealing temperature for heat-sealing the packaging film to the substrate is preferably T _m2 to T _m1 °C, more preferably T _m2 +10 °C to T _m1 -10 °C. When the heat welding temperature is set to the above lower limit or more, the packing film can be sufficiently welded to the substrate, and when it is set to the above upper limit or less, breakage of the packing film due to excessive heating can be prevented.
The pressing force of the heat seal bar when heat-sealing the packaging film to the substrate is preferably 5 to 50 N/cm ² , more preferably 10 to 40 N/cm ² . If the pressing force of the heat seal bar is above the lower limit, the packaging film can be sufficiently welded to the substrate, and if below the upper limit, breakage of the packaging film due to excessive pressure is prevented. can.

FIG. 2 shows one embodiment of the packing member of this aspect.
The packaging member 1 of the present embodiment includes the rectangular packaging film 10 of the above-described embodiment and a rectangular paper substrate 20 . In this embodiment, the area of the paper substrate 20 in plan view is larger than the area of the packaging film 10 in plan view. The packing film 10 is thermally welded to the paper base material 20 at the peripheral edges of the long sides thereof. In this embodiment, the packaging film 10 is heat-sealed to the paper substrate at the peripheral portion 10a.
In the packing member 1 of the present embodiment, since the packing film 10 of the above embodiment is used, the packing film 10 is adhered to the paper substrate 20 with high adhesive strength without being deformed or melted. ing.
Since a gap can be formed between the packing film 10 and the paper base material 20 in the unattached portion of the packing film 10 which is not heat-sealed to the paper base material 20, an article can be accommodated therebetween.

In the packaging member 1 of the present embodiment, the packaging film 10 has elasticity and can be easily stretched, so that the article can be inserted between the packaging film 10 and the paper substrate 20 in the unattached portion, An article can be sandwiched between the packaging film 10 and the paper substrate 20.例文帳に追加Since the packaging film 10 of this embodiment has elasticity and tends to shrink when stretched, the article sandwiched between the packaging film 10 and the paper substrate 20 can be firmly fixed and packaged. Therefore, the packing member 1 of this embodiment has a high article holding power.

The packing member 1 is housed in a packing container and used. Specifically, the packing member 1 is housed in a packing container and used when transporting an article.
Examples of packing containers include boxes, bags, and the like, and boxes are usually used. Examples of materials for the packing container include paper and resin, among which paper is preferable, and corrugated cardboard is more preferable. For these reasons, a corrugated cardboard box is particularly preferable as a packing container.
The packing member 1 preferably has a shape that is fixed inside the packing container even against vibration during transportation.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to the following examples.
In addition, the following materials were used in the following examples.
Prime Polypro F227, manufactured by Prime Polymer Co., Ltd.: random polypropylene, melting point 152° C., density 0.910 g/cm ³ . Hereinafter, it is described as "Polymer 1".
ExxonMobil, Vistamax 3588FL: block polypropylene, melting point 109°C, density 0.889 g/cm ³ . Hereinafter, it is described as "Polymer 2".
ExxonMobil, Vistamax 6102FL: olefinic thermoplastic elastomer, no melting point, density 0.862 g/cm ³ . Hereinafter, it is described as "elastomer 1".
ExxonMobil, Vistamax 8880: olefinic thermoplastic elastomer, no melting point, density 0.879 g/cm ³ . Hereinafter, it is described as "elastomer 2".
Rikemaster ELM080, manufactured by Riken Vitamin Co., Ltd.: A masterbatch containing a slip agent and erucic acid amide. Hereinafter, it is written as "slip agent MB".

<Production of packaging film>
(Example 1)
100 parts by mass of polymer 1 is used as the resin material for forming the first outer layer, 95 parts by mass of polymer 2 and 5 parts by mass of slip agent MB are used as the resin material for forming the second outer layer, and 100 parts by mass of elastomer 1 is used to form the intermediate layer. It was made into a resin material for These resin materials were fed into an extruder capable of multi-layer molding. An extruder with a multi-manifold die attached to the tip was used. The die temperature was 200°C.
Each resin material was extruded by the extruder and laminated so that the intermediate layer was arranged between the first outer layer and the second outer layer. The thickness of each layer was as shown in Table 1.
A three-layer laminate in a molten state molded by an extruder was adhered to the peripheral surface of a cast roll adjusted to 25° C. and cooled to obtain a packaging film.

(Examples 2 to 20, Comparative Examples 3 and 4)
A packaging film was obtained in the same manner as in Example 1, except that the composition or layer thickness of the first outer layer, second outer layer and intermediate layer was changed as shown in Tables 1 to 3.

<Evaluation>
The packing films of each example and each comparative example were evaluated as follows. The evaluation results are shown in Tables 1-3.

[Anti-blocking property]
When the roll-shaped packing film was unwound, the condition of unrolling was visually observed, and the anti-blocking property was evaluated according to the following criteria.
1: The adhesive strength between the packaging films was weak, the smoothness of the delivery of the packaging film was high, and the anti-blocking property was excellent.
2: The adhesive force between the packaging films was slightly weak, and the delivery of the packaging films was sometimes not smooth, but this did not pose a problem and had antiblocking properties.
3: The adhesive force between the packing films was strong, the packing film was not smoothly delivered, and the anti-blocking property was insufficient.

[Goods retention]
The holding property of the article was evaluated from the stretchability of the packing film. Specifically, first, five test pieces each having a width of 25 mm and a length of 100 mm were cut out from the obtained packing film. The test piece was attached to a chuck of a tensile tester (Trapezium 2 manufactured by Shimadzu Corporation), and a tensile test was performed until the stretch ratio of the test piece reached 100%. The tensile test conditions at that time were a measurement temperature of 23° C., a distance between chucks of 25 mm, and a tensile speed of 254 mm/min. The tensile strength at a stretch ratio of 100% was measured for each test piece, and the average value (tensile strength at 100% stretch) was obtained. If the tensile strength at 100% stretching is in the range of 2.00 to 6.00 N/25 mm, the article can be easily held in the packaging member produced using the packaging film, which is preferable. If the tensile strength at 100% stretching is less than 2.00 N/25 mm, the packaging film may break during packaging of articles. When the tensile strength at 100% stretching exceeds 6.00 N/25 mm, the packaging film is difficult to stretch, and it may be difficult to insert an article between the substrate and the packaging film in the packaging member. Therefore, when the tensile strength at 100% stretching is in the range of 2.00 to 6.00 N/25 mm, the article holding property is excellent.

[Goods packaging]
The packing property of the article was evaluated from the restorability of the packing film. Specifically, in the evaluation of the article holding property, the test piece was stretched at a stretch rate of 100%, and after 30 seconds had passed, the pulling was stopped and the chucks were brought closer to restore the shape of the test piece. After 60 seconds had elapsed after the stretch ratio of the test piece reached 0%, the test piece was again stretched under the above tensile conditions until the stretch ratio of the test piece reached 100%. After 30 seconds had passed after the test piece was stretched at a stretch rate of 100%, the pulling was stopped and the chucks were brought closer to restore the shape of the test piece. At that time, the tensile strength at an elongation rate of 50% was measured for each test piece, and the average value (tensile strength at 50% restoration) was obtained. If the tensile strength at 50% restoration is in the range of 0.30 to 2.00 N/25 mm, the packing member produced using the packing film has good packing properties, which is preferable. If the tensile strength at 50% restoration is less than 0.30 N/25 mm, there is a risk that the packing film will break when packing the article. If the tensile strength at 50% restoration exceeds 2.00 N/25 mm, the shrinkage force of the packaging film is too strong, and there is a risk of deformation of the packaged article. Therefore, when the tensile strength at 50% restoration is in the range of 0.30 to 2.00 N/25 mm, the article packaging properties are excellent.

<Results>
The packing film of each example, which satisfies the definition of claim 1 of the present application, was excellent in anti-blocking property and article holding property. In addition, Examples 1, 2, 6, 8, 11 and 11, in which the thickness of the first outer layer is 3 to 10 μm, the thickness of the second outer layer is 1 to 10 μm, and the thickness of the intermediate layer is 20 to 50 μm, The packing films of Nos. 13 to 20 were also excellent in article packaging properties.
The packaging film of Comparative Example 3, in which the density of the polymer contained in the second outer layer was less than 0.87 g/cm ³ , had low antiblocking properties.
The packing film of Comparative Example 4, in which the material contained in the intermediate layer is a polymer that is not a thermoplastic elastomer, had poor article holding properties and article wrapping properties.

1 packing member 10 packing film 11 first outer layer 12 second outer layer 13 intermediate layer 20 paper substrate

Claims (2)

A packaging film comprising one outer layer, the other outer layer, and an intermediate layer provided between the one outer layer and the other outer layer,
The polymer contained in the one outer layer and the polymer contained in the other outer layer are polymers having a density of 0.87 g/cm ³ or more,
At least one of the polymer contained in the one outer layer and the polymer contained in the other outer layer is a block polypropylene containing a rubber component in a matrix of homopolypropylene or random polypropylene containing 5% by mass or less of ethylene units. Yes ,
The intermediate layer contains a thermoplastic elastomer,
A packaging film , wherein the thickness of the one outer layer and the thickness of the other outer layer are 2 μm to 6 μm, and the thickness of the intermediate layer is 20 to 50 μm . A packaging member comprising the packaging film of claim 1 and a substrate to which the packaging film is attached.

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