JP3120325B2 - Film for packaging metal products - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal product packaging film for packaging a metal product composed of a plurality of types of metals requiring rust prevention.

[0002]

2. Description of the Related Art Conventionally, as a packaging material for protecting metal products from rust and discoloration, a film made of a thermoplastic resin containing a rust inhibitor, rust-proof paper containing a rust-preventive agent, and rust-proof paper have been used. A packaging material or the like made of a combination with a film such as a polyethylene film is used.

[0003]

As a typical rust preventive used in conventional packaging materials, dicyclohexylammonium nitrite (hereinafter referred to as D) is known.
ICHAN), benzotriazole, sodium nitrite and the like, but these rust preventive agents do not have a universal rust preventive effect on a plurality of types of metals. For example, when DICHAN is used as a rust inhibitor, rust-preventing effect on irons is recognized, but non-ferrous metals such as aluminum and copper have severe corrosiveness. It is necessary to add a rust preventive, and the kind of applicable metal is limited with one kind of rust preventive.

[0004] Therefore, when a rust preventive effective for irons and a rust preventive effective for non-ferrous metals are melt-kneaded in the same synthetic resin, a mutual thermal reaction occurs and the stability to heat is further reduced. Because of this tendency, usable thermoplastic resins and molding temperatures are limited.

Further, as a packaging film effective for rust prevention of a plurality of types of metals, a multilayer film formed by laminating a plurality of layers each containing a different rust preventive agent in a thermoplastic resin is disclosed in Japanese Patent Application Laid-Open No. HEI 1-1990. It is disclosed in JP-A-210340. However, in such a multilayer film, the thermoplastic resin layers each containing a rust inhibitor are laminated in a molten state, so that different rust inhibitors tend to react at the contact surfaces between the layers. In this case, there is a problem that molding conditions are limited and usable thermoplastic resins are limited. In addition, in this multilayer film, the effect of the rust inhibitor contained in the innermost layer when covering the metal product is large, whereas the rust preventive effect of the rust inhibitor contained in the outer layer is reduced, and It is difficult to sufficiently exhibit the rust-preventive effect of the rust preventive.

[0006] The present invention has been made in view of such circumstances, and enables the use of thermoplastic resins in a wide range and allows molding with moderate restrictions on molding conditions. It is an object of the present invention to provide a metal product packaging film capable of obtaining an excellent rust prevention effect.

[0007]

The film for packaging metal products of the present invention has a plurality of strip-shaped rust preventive portions each containing a different kind of rust preventive agent in a thermoplastic resin. Are arranged alternately in the plane direction.

In such a film for packaging metal products,
Different types of rust preventives are not melt-kneaded in the thermoplastic resin. Even if the rust preventive parts are adjacent to each other, the contact area between the rust preventive parts is minimized to prevent rust. The thermal reaction between the agents can be suppressed, the range of usable thermoplastic resins can be expanded, and the molding temperature is not limited. Moreover, the vaporization component of each rust inhibitor is
By forming a monomolecular film on the surface of each individual metal, or by bonding vaporized components to each other and adsorbing on the surface of the metal, an effective rust prevention effect can be obtained for a plurality of types of metals.

Further, in the film for packaging metal products of the present invention, a plurality of strip-shaped rust-preventing portions each containing a different kind of rust-preventive agent in a thermoplastic resin are arranged so as to be shifted from each other in the plane direction. A coating layer made of a thermoplastic resin containing no rust preventive is laminated on the rust preventive layer.

[0010] In this film for packaging metal products, the rust preventive layer makes it possible to obtain an effective rust preventive effect on a plurality of metals, and the coating layer seals the vaporized components from the strip-like rust preventive portion of the rust preventive layer. And it is possible to obtain a more excellent rust prevention effect, and it is possible to reduce the moisture permeability from the outside air to the inside.

[0011]

Figure 1 DETAILED DESCRIPTION OF THE INVENTION is a perspective view of a metal product package film of the first embodiment of the present invention, the metal product package film F ₁ is a first rust inhibitor in the thermoplastic resin A plurality of strip-shaped rust preventive parts 1 ₁ ... And a plurality of strip-shaped rust preventive parts 1 ₂ .
Are formed in such a manner that the strip-shaped rust preventive portions 1 ₁ , 1 _2, ... are alternately arranged in the plane direction.

Examples of the thermoplastic resin containing a rust preventive include polyolefin resins such as low-density polyethylene, medium-density polyethylene, linear low-density polyethylene, high-density polyethylene, polypropylene, and butene-1;
Copolymer resins such as vinyl acetate and acrylate, polystyrene resins such as polystyrene, acrylonitrile / styrene, acrylonitrile / butadiene / styrene, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, nylon 6, nylon 12, amorphous Polyamide resins such as high-quality nylon and synthetic resins such as ionomers are preferably used.

Examples of rust preventives include triammonium phosphate, ammonium molybdate, DICHAN (dicyclohexylammonium nitrite), dicyclohexylammonium caprylate, cyclohexylamine carbamate, cyclohexylamine laurate, diisopropylammonium nitrite, Ammonium nitronaphthalene nitrite, ammonium benzoate, cyclohexylamine benzoate,
Dicyclohexylamine phosphate, sodium nitrite, sodium chromate, thiourea, urotropin, benzotriazole, methylbenzotriazole, 3-methyl-5
-Hydroxypyrazole, 5-amino-1H-tetrazole, 2-heptadigilimidazole, 3-methyl-5
-Pyrazolone, triazinedithiol monosodium,
1-hydroxyethylidene-1, 1-diphosphonic acid, nitrotrimethylene phosphonic acid, sodium phenylanthranilate and the like are preferably used.

These rust preventives may be used alone or in appropriate combination with each other. Particularly, when a rust preventive having a relatively low melting point or decomposition temperature of 50 to 100 ° C. is used, ethylene-acetic acid may be used. It is desirable to knead and incorporate into a thermoplastic resin having a relatively low melting point, such as a copolymer resin such as vinyl or acrylic ester. Further, when a rust preventive having a melting point or decomposition temperature of 120 to 200 ° C. and relatively high thermal stability is used, the selection range of the thermoplastic resin to be used becomes large.

In order to incorporate the rust preventive into the thermoplastic resin, the rust preventive is kneaded with pellets and powder of the thermoplastic resin using an appropriate kneading means, and the mixture is mixed with a Banbury mixer, a mixing roll kneader and a twin-screw kneader. Compounding may be carried out using an apparatus such as an extruder, or the pellets and the rust preventive may be directly blended and then charged into a film forming machine.

In film formation, inflation
Melt extrusion molding such as the solution method or the T-die method is preferred.
It is used appropriately and, as shown in FIG.
Different rust inhibitors in the thermoplastic resin
Strip-shaped rust prevention part 1₁…, 1_Two… Are arranged alternately in the plane direction
Metallic product packaging film F₁In forming
For example, when the T-die method is used, FIG.
A film forming machine as shown is used. This film
The molding machine presses the thermoplastic resin containing the first rust inhibitor.
First extruder 3₁And heat containing the second rust inhibitor
Second extruder 3 for extruding plastic resin_TwoAnd their extrusion
Machine 3₁, 3_TwoDies 4 that are commonly mounted₁Composed of
Is done. And die 4₁Has a first extruder 3₁Connected to
A plurality of first flow paths 5₁... and the second extruder 3_TwoLinked to
Plural second flow paths 5_Two... and the first flow path 5₁… Individually
Multiple first lips 6₁... and the second flow path 5_Two… Individually
A plurality of second lips 6 leading to_TwoAre provided, and the first lip is provided.
Step 6₁… And the second lip 6 _Two… Are alternately adjacent
And die 4₁It is arranged in.

According to such a film forming machine, the first
Molten heat was contained rust thermoplastic resin and a thermoplastic resin containing a second rust preventive in the extruder 3 _1, 3 _2, and kneaded, from those of the extruder 3 _1, 3 ₂ The extruded thermoplastic is applied to adjacent lips 6 ₁ …,
6 ₂ ... And a plurality of strip-shaped rust prevention parts 1 ₁ .
1 ₂ ... is the metal product package film F ₁ comprising alternately arranged in the surface direction can be obtained.

In the case of the inflation method,
Wherein the T- die method die 4 ₁ lip 6 ₁ ..., circular tube die having 6 ₂ ... a similar resin discharge port is used.

[0019] By metal product composed of a plurality kinds of metals in this way the metal obtained by product packaging film F ₁ is packaged, the vaporized component of the rust inhibitor, a monomolecular film on the individual metal surface To form an effective rust-preventing effect on a plurality of types of metals. In addition, a combination of rust inhibitors that synergize irons with a mixed system such as sodium nitrite and urea, which synergistically exerts rust-preventive effects on irons, causes severe thermal decomposition when mixed in the same thermoplastic resin. The rust-preventing effect is exhibited by the thermoplastic resins contained individually being displaced from each other in the plane direction, so that the mutually vaporized rust-preventive components are mutually bonded in a packaged atmosphere. Become like

It is preferable that the thermoplastic resin containing the rust preventive agent be similar thermoplastic resin, since it is difficult to cause tearing at the mutual contact portion. However, in order to prevent the occurrence of tearing, it is desirable to use a compatibilizing agent. Alternatively, a tackifier may be added to the thermoplastic resin.

Incidentally, the rust preventive may give discoloration and corrosion to a certain kind of metal, and such a negative effect is caused by finely adjusting the width of each band-shaped rust preventive portion 1 ₁ , 1 ₂ . By doing so, the width can be suppressed to an allowable range, and the width thereof is preferably adjusted to about 5 to 120 mm, although it varies depending on the target metal product.

As a second embodiment of the present invention, as shown in FIG. 3, a plurality of strip-shaped rust preventive portions 1 ₁ ... a plurality of band-like rust section 1 ₂ ... and their strip rust portion made contain a second rust inhibitor 1 ₁ ..., 1 ₂ ... rust layer 7 constituted are arranged alternately in a plane direction When the coating layer 8 made of a thermoplastic resin may be be laminated to each other forming a metal product wrapping film F ₃ containing no corrosion inhibitor.

Such a metal product packaging film F_TwoFormation
For example, when the T-die method is used
For this, a film forming machine as shown in FIG. 4 is used. This
Of the film forming machine is a thermoplastic resin containing the first rust inhibitor
First extruder 3 for extruding conductive resin ₁And a second rust inhibitor
Second extruder 3 for extruding the thermoplastic resin_TwoAnd prevention
Third extruder 3 for extruding rust-free thermoplastic resin
_ThreeAnd their extruders 3₁, 3_Two, 3_ThreeAre commonly mounted
Die 4_TwoIt is composed of This die 4₁In
First extruder 3₁Plurality of first flow paths 5 connected to₁… And the
2 extruder 3_TwoPlurality of second flow paths 5 connected to_Two... and the third
Extruder 3_ThreeThird flow path 5 connected to_ThreeAnd the first flow path 5₁…
First lips 6 that individually communicate with₁... and the second flow path 5
_TwoA plurality of second lips 6 individually leading to ..._Two… And the third style
Road 5_ThreeThird lip 6 leading to_ThreeAnd the first lid
Step 6₁… And the second lip 6_Two… Are adjacent alternately in the horizontal direction
To die 4_TwoAnd the third lip 6
_ThreeIs the first and second lip 6₁…, 6_Two… Up, down
Die 4_TwoIt is arranged in.

According to such a film forming machine, the first
Resin containing a second rust inhibitor and a second rust inhibitor
The extruder 3 contains a thermoplastic resin containing an agent.₁, 3_Twoso
Melted and kneaded, and their extruders 3₁, 3_TwoExtrusion from
Extruded without thermoplastic resin and rust inhibitor
Machine 3_ThreeThermoplastic resin extruded from
Top 6₁…, 6_Two…, 6_ThreeMelt contact with each other
Strip-shaped rust prevention part 1_Two…, 1 _Two… Are arranged alternately in the plane direction
The rust preventive layer 7 is made of a thermoplastic resin containing no rust preventive.
Product packaging film F having a coating layer 8 laminated thereon
_TwoIs obtained.

The metal product packaging film F ₂ is used in such a manner that the coating layer 8 is disposed outside when packaging a metal product, and according to the second embodiment, the first product In addition to achieving the same effects as the embodiment,
The coating layer 8, the strip rust portion 1 ₂ of the anticorrosive layer 7 ..., 1 ₂ ...
It is possible to obtain a more excellent rust-preventing effect by improving the sealing property of the vaporized component from the air, and to reduce the moisture permeability from the outside air to the inside.

The strip-shaped rust preventive part 1 containing each rust preventive agent 1 ₁
, 1 ₂ ... need not necessarily be arranged alternately adjacent to each other, and a portion of the thermoplastic resin containing no rust preventive may be arranged between the strip-shaped rust preventive portions 1 ₁ , 1 ₂ ... However, even in such a metal product packaging film, the vaporized components of each rust inhibitor form a monomolecular film on the individual metal surface, or the vaporized components are mutually bonded and adsorbed on the metal surface. An effective rust prevention effect can be obtained for a plurality of types of metals.

FIG. 5 shows a third embodiment of the present invention, in which a plurality of strip-shaped rust preventive portions 1 ₁ ... Made of a thermoplastic resin containing a first rust preventive agent and a rust preventive agent are included. Are alternately arranged adjacent to each other.
The layer 11, a plurality of strip-shaped rust-preventing portions 1 ₂ ... Formed by adding a _second rust preventive to a thermoplastic resin, and the strips 10 formed of a thermoplastic resin not containing a rust preventive are alternately adjacent to each other. a second layer 12 formed by arranged, strip rust of the first layer 11 with strip rust portion 1 ₂ of the second layer 12 ... is disposed in a portion corresponding to the belt-like portion 9 ... of the first layer 11 by part 1 ₁ ... they are laminated to each other so as to be disposed in a portion corresponding to the belt-like portion 10 ... of the second layer 12, metal products packaging film F ₃
Is formed.

According to the third embodiment, since the contact area of the contact portion between the thermoplastic resins containing the rust inhibitor can be minimized, the rust preventive agent, which has high mutual reactivity due to heat, can be used. Even if it is used, it is possible to minimize the limitation of the usable thermoplastic resin and the limitation of the molding temperature. Moreover it is stacked in the respective strip-like rust portions 1 _1, 1 _2, since it is the strip portion 10, 9 made of thermoplastic resin containing no corrosion inhibitor, effects rust agent to each other by lamination section of the cross to avoid that the mutually-the anticorrosive effect of the vaporized component of the corrosion inhibitor from the strip rust portions 1 _1, 1 ₂ can be sufficiently exhibited.

Therefore, even if a plurality of strip-shaped rust preventive portions are formed on each of the layers 11 and 12 by a rust preventive having high mutual reactivity, a sufficient rust preventive effect can be obtained. The types of agents can be increased.

Next, Examples 1 to 5 formed according to the present invention
The results of the rust prevention test performed by the present inventors using the films of Comparative Examples 1 to 3 formed by laminating a thermoplastic resin containing a rust inhibitor are described in Examples 1 to 5. Master batch pellets of four kinds of rust inhibitors prepared as follows were used.

First master batch pellet; ethylene-vinyl acetate copolymer resin (D205 manufactured by Sumitomo Chemical Co., Ltd.)
3, density 0.92, melt index MI = 7.5)
After adding 20.0% by weight of DICHAN, the mixture was kneaded with a twin-screw extruder, melted at a molding temperature of 110 ° C., extruded, cooled by an air cooling method, and pelletized by a pelletizer.

Second masterbatch pellet: a masterbatch pellet containing 20.0% by weight of diisopropylammonium nitrite, prepared under the same conditions as the first masterbatch pellet.

Third masterbatch pellet; ethylene / methyl acrylate copolymer resin (manufactured by Nippon Oil Co., Ltd.)
RB5120, density 0.933, MI = 10.0), 8.0 wt% of benzotriazole was added, kneaded with a twin-screw extruder, melted at a molding temperature of 95 ° C., extruded, and air-cooled. The mixture was cooled by a method and pelletized by a pelletizer.

Fourth master batch pellet; a master batch pellet containing 8.0% by weight of methylbenzotriazole, prepared under the same conditions as the third master batch pellet.

Example 1 Low-density polyethylene resin (F218-1, manufactured by Sumitomo Chemical Co., Ltd., density 0.919,
MI = 1.0) 100 parts by weight of the first masterbatch pellets and 8 parts by weight of the first masterbatch are well blended, and a low-density polyethylene resin rust-proof part containing 1.5% by weight of DICHAN has a width of 130 ° C. at a melting temperature of 130 ° C. While adjusting to 15 mm, 100 parts by weight of the low-density polyethylene resin and 5 parts by weight of the third masterbatch pellet were well blended,
A band-shaped rust preventive part of a low-density polyethylene resin containing 0.4% by weight of benzotriazole was melted at 120 ° C. and the width was 20
mm, and both band-shaped rust-proof parts were alternately arranged and joined in a plane direction at a set temperature of 135 ° C. with an inflation molding die to form a metal packaging film having a structure shown in FIG.
m.

Example 2 Under the same molding conditions as in Example 1, the belt-shaped rust-proof portion of a low-density polyethylene resin containing 1.5% by weight of DICHAN was adjusted to a width of 15 mm, and benzotriazole was added at a weight of 0.4%. % Of the low-density polyethylene resin is adjusted to a width of 20 mm to form a 100-μm-thick rust-preventive layer in which both zonal rust-preventive parts are alternately arranged and joined in the plane direction, and a rust-preventive agent is included. High density polyethylene resin as a thermoplastic resin (RS1000 manufactured by Tonen Chemical Co., Ltd., density 0.951,
MI = 0.15) at 160 ° C. to 30 μm to form a coating layer, and the rust prevention layer and the coating layer are laminated,
The film for metal packaging having the configuration shown in FIG. 3 was formed into a thickness of 130 μm.

[Example 3] A linear low-density polyethylene resin (0438, manufactured by Idemitsu Petrochemical Co., Ltd., density 0.9,
MI = 4.0) 100 parts by weight of the second masterbatch pellets and 8 parts by weight of the second masterbatch are well blended, and a strip-shaped rust preventive part of a linear low-density polyethylene resin containing 1.5% by weight of diisopropylammonium nitrite. The melting temperature 13
At 0 ° C., the width was adjusted to 10 mm and an ethylene / methyl acrylate copolymer resin (RB5 manufactured by Nippon Oil Co., Ltd.) was used.
120, density 0.933, MI = 10.0) 100 parts by weight of the fourth masterbatch pellet and 5 parts by weight of an ethylene / methyl acrylate copolymer resin containing 0.4% by weight of methylbenzotriazole Was adjusted to a width of 30 mm at a melting temperature of 100 ° C., and the two rust preventing portions were alternately arranged and joined in a plane direction at a set temperature of 135 ° C. using a T-die to obtain a structure shown in FIG. The metal packaging film was formed to a thickness of 150 μm.

Example 4 Under the same molding conditions as in Example 3, 1.5 g of diisopropylammonium nitrite was used.
In addition to adjusting the width of the strip-shaped rust-preventive portion of the linear low-density polyethylene resin containing 10% by weight to 10 mm, ethylene-containing resin containing 0.4% by weight of methylbenzotriazole was used.
30 m wide rust preventive part of methyl acrylate copolymer resin
m, and formed a 150 μm-thick rust-preventive layer in which both belt-shaped rust-preventive parts were alternately arranged and joined in the surface direction, and an ionomer resin (a Mitsui DuPont Co., Ltd.) as a thermoplastic resin containing no rust-preventive agent 3) was formed at a temperature of 165 ° C. and adjusted to 40 μm to form a coating layer, and the rust preventive layer and the coating layer were laminated to form a metal package having the structure shown in FIG. 190 for film
It was molded to a thickness of μm.

Example 5 A low-density polyethylene resin containing 0.8% by weight of sodium nitrite as a first rust inhibitor (F218-1 manufactured by Sumitomo Chemical Co., Ltd., density 0.919,
(MI = 1.0) at a melting temperature of 150 ° C. and a width of 1
0 mm, the band-shaped rust-proof part of a low-density polyethylene resin containing 0.4% by weight of benzotriazole as a second rust preventive was adjusted to a melting temperature of 125 ° C. and a width of 20 mm, and the third rust preventive was further adjusted. Rust preventive part of ethylene-vinyl acetate copolymer resin containing 0.5% by weight of urea as an agent was prepared to have a melting temperature of 130 ° C. and a width of 15 mm, and each rust preventive part was set at an inflation molding die at a set temperature. At 135 ° C., it is alternately arranged and joined in the plane direction, and the film for metal packaging is 100 μm.
m.

COMPARATIVE EXAMPLE 1 A low-density polyethylene resin containing 1.5% by weight of DICHAN and having a thickness of 50 μm
m and an outer layer made of a low-density polyethylene resin containing 0.4% by weight of benzotriazole and having a thickness of 50 μm under the molding conditions corresponding to Example 1 and a two-layer inflation die at a molding temperature of 140 ° C. To form a two-layer film having a thickness of 100 μm.

COMPARATIVE EXAMPLE 2 An inner layer of a 55 μm thick linear low-density polyethylene resin containing 1.5% by weight of diisopropylammonium nitrite and a linear layer containing 0.4% by weight of methylbenzotriazole Forming a 55 μm-thick intermediate layer made of a low-density polyethylene resin and an outer layer having a thickness of 40 μm made of an ionomer resin under molding conditions corresponding to Example 4;
-Laminated with a die at a molding temperature of 145 ° C, thickness 150μ
m was formed into a three-layer film.

Comparative Example 3 A low-density polyethylene resin containing 0.8% by weight of sodium nitrite and having a thickness of 45 μm
m and an intermediate layer having a thickness of 25 μm made of a low-density polyethylene resin containing 0.4% by weight of benzotriazole were formed under the molding conditions corresponding to Example 5, and laminated at 125 ° C. Of an ethylene-vinyl acetate copolymer resin containing 0.5% by weight of a resin and melt-extruded at a temperature of 140 ° C. to a thickness of 30 μm and laminated by a three-layer laminating inflation method at a molding temperature of 145 ° C.
An attempt was made to form a three-layer film of 0 μm, but the film could not be formed due to foaming.

Examples 1 to 5 obtained as described above
In addition, the rust prevention test of the films of Comparative Examples 1 and 2 was performed in the following procedure.

First, the films of Examples 1 to 5 and Comparative Examples 1 and 2 were heat-sealed to 600 mm × 9.
A 00 mm bag is formed, and the four types of test pieces shown in Table 1 are air-dried and then stored in the bags.

[0045]

[Table 1]

Next, after the test pieces are stored, each bag is heat-sealed and sealed again, and pure water is heated with a heater to control the temperature and humidity in the atmosphere.
The test pieces were allowed to stand for 14 days under a high-temperature and high-humidity atmosphere of 95 ° C. and a relative humidity of 95% or more, and the rate of occurrence of rust and discoloration with respect to the entire area of each test piece was evaluated according to the following evaluation criteria.

Evaluation criteria ◎: No rust, discoloration ○: Spot rust, slight discoloration occurred △: Less than 10% rust or discoloration occurred to test piece area ×: 10 to 50% to test piece area Rust or discoloration occurred XX: Rust or discoloration occurred 50% or more with respect to the area of the test piece. The results of this evaluation are shown in Table 2.

[0048]

[Table 2]

As is clear from Table 2, Comparative Examples 1 and 2 have an excellent rust-preventing effect on a certain metal (steel plate), but have a universal rust-preventing effect on a plurality of metals. Without
In the films of Examples 1 to 5 formed according to the present invention, an excellent rust prevention effect can be obtained for a plurality of metals.

Although the embodiments of the present invention have been described in detail, the present invention is not limited to the above embodiments, and various design changes can be made without departing from the present invention described in the appended claims. It is possible to do.

[0051]

According to the invention above the claim 1, wherein, according to the present invention, a plurality of band-like rust part exchange the plane direction comprising a thermoplastic resin to different types of corrosion inhibitors to respectively be contained individually
By arranging them mutually, it is possible to minimize the occurrence of thermal reaction between the rust preventive agents and relax the restrictions on molding conditions, and to expand the range of usable thermoplastic resins. The vaporization component of the agent forms a monomolecular film on the surface of each individual metal, or the vaporization components combine with each other and adsorb on the metal surface to obtain an effective rust prevention effect for multiple types of metals. Can be.

According to the second aspect of the present invention, a plurality of strip-shaped rust-preventing portions each containing a different kind of rust-preventing agent in the thermoplastic resin are arranged to be shifted from each other in the plane direction. The effect of the invention according to claim 1 can be obtained by laminating a coating layer made of a thermoplastic resin containing no rust preventive agent on the rust preventive layer. It is possible to improve the sealing properties of the components to obtain a more excellent rust prevention effect, and to further reduce the moisture permeability from the outside air to the inside of the package.

[Brief description of the drawings]

FIG. 1 is a perspective view of a metal product packaging film according to a first embodiment.

FIG. 2 is a schematic view of a film forming machine for forming the metal product packaging film of FIG. 1;

FIG. 3 is a perspective view of a metal product packaging film according to a second embodiment.

FIG. 4 is a schematic view of a film forming machine for forming the metal product packaging film of FIG. 3;

FIG. 5 is a perspective view of a metal product packaging film according to a third embodiment.

[Explanation of symbols]

1 ₁ , 1 ₂ ··· Strip rust preventive part 7 ··· Rust prevention layer 8 ··· Coating layer F ₁ , F ₂ , F ₃ ··· Film for metal product packaging

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B65D 65/40 B32B 27/00 B32B 27/18 B32B 27/32

Claims (2)

(57) [Claims] 1. A plurality of strip-shaped rust preventive portions (1 ₁ , 1 ₂ ) each containing a different kind of rust preventive agent in a thermoplastic resin, respectively. ₁ , 1
₂ ) A film for packaging metal products, wherein the films are alternately arranged in the plane direction. 2. A proof that a plurality of strip-like rust portion thermoplastic resin to different types of corrosion inhibitors and comprising each be contained individually (1 _1, 1 ₂₎ are displaced from each other in the planar direction A film for packaging metal products, comprising a rust layer (7) and a coating layer (8) made of a thermoplastic resin containing no rust preventive.