Rust-proof film

Abstract

A rust-preventive film comprising at least recycled polyethylene, a vaporizable rust inhibitor, and an antioxidant, wherein the vaporizable rust inhibitor is selected from carboxylic acid esters and heterocyclic aromatic compounds, and the antioxidant is a phenolic antioxidant.

Description

Technical Field

[0001] This disclosure relates to a rust-preventive film, and more specifically, to a rust-preventive film used to inhibit oxidation and rusting of metal surfaces during storage, handling, and transportation after packaging metal components such as mechanical parts. Background Technology

[0002] Traditionally, when storing metal components for extended periods, the usual method to prevent rust is to apply rust-preventive oil, then package and store them. For various mechanical parts that cannot be prevented from rusting by applying rust-preventive oil, methods are known to use vaporized rust inhibitors as an alternative to rust-preventive oil, or to package and store rust-preventive films obtained by mixing vaporized rust inhibitors into resin films and forming them.

[0003] In the aforementioned rust-preventive films using vaporizable rust inhibitors, permeability is required to allow the rust inhibitor to vaporize. In single-layer films, the vaporizable rust inhibitor evaporates not only into the packaging but also to the outside; therefore, a multilayer film structure is adopted. For example, a multilayer film obtained by laminating a resin film containing a vaporizable rust inhibitor with a substrate film such as nylon has been proposed. It is believed that, based on such a multilayer rust-preventive film, the diffusion or volatilization of the vaporizable rust inhibitor to the outer layer (atmospheric side) can be suppressed, thereby maintaining a high rust-preventive effect for a long time (e.g., Patent Document 1).

[0004] In addition, a multilayer film has been proposed in which the innermost layer contains a vaporizable rust inhibitor, the middle layer has a layer containing a gas barrier resin, and the outermost layer has a substrate layer. It is known that, according to this multilayer film, by setting the middle layer, the barrier performance against vaporizable gases, oxygen or water vapor of the rust inhibitor is improved (e.g., Patent Document 2, etc.).

[0005] In addition, multi-layered anti-rust films have been disclosed, which are obtained by laminating a shielding film with a vapor-deposited film and an organic coating layer on a sealing layer to improve barrier performance (for example, Patent Document 3).

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2013-059864

[0009] Patent Document 2: Japanese Patent Application Publication No. 2019-155611

[0010] Patent Document 3: Japanese Patent Application Publication No. 2020-189689 Summary of the Invention

[0011] The problem that the invention aims to solve

[0012] However, in recent years, from the perspective of reducing environmental burden, the use of recycled products has been recommended. Recycled resin products are also being actively explored in areas such as packaging films. However, the reality is that while there are commercially available recycled resins for polyester, polyethylene, and other resins, there are no recycled products available for special gas-barrier resins.

[0013] In addition, for example, when polyethylene obtained from material recycling is remelted during the recycling process, antioxidants are sometimes added to prevent thermal decomposition and gelation. Phenolic antioxidants and phosphoric acid antioxidants are used as such antioxidants to prevent the thermal degradation of polyethylene.

[0014] In a rust-preventive film containing the vaporizable rust inhibitor as described above, if an antioxidant is included in the recycled polyethylene constituting the resin film, the antioxidant will deactivate the vaporizable rust inhibitor, thus reducing the rust-preventive effect of the rust-preventive film.

[0015] Furthermore, it is known that recycled polyethylene contains impurities and components of varying purity levels, thus requiring a higher film-forming temperature compared to virgin polyethylene resin. Therefore, if recycled resin is intended for use in rust-preventive films, there is a risk of accelerated thermal decomposition and volatilization of the rust inhibitor.

[0016] Therefore, the purpose of this disclosure is to provide a rust-preventive film that still has excellent rust-preventive effect while using recycled resin.

[0017] Methods for solving problems

[0018] The inventors have realized that, even when the recycled polyethylene resin contains an antioxidant, if the antioxidant is a specific compound and the vaporizable rust inhibitor used is also a specific compound, the deactivation of the vaporizable rust inhibitor caused by the antioxidant as described above can be suppressed, thus enabling the production of a rust-preventive film that still exhibits excellent rust-preventive effects while using recycled resin. The first aspect of this disclosure is based on this realization.

[0019] Furthermore, the inventors have also realized that by containing a vaporizable rust inhibitor in a layer formed from virgin polyethylene that does not contain an antioxidant, and by forming a layer different from a layer formed from recycled polyethylene that contains an antioxidant, it is possible to suppress the deactivation of the vaporizable rust inhibitor caused by the antioxidant, and to achieve a rust-preventive film that still has excellent rust-preventive effect while using recycled resin. The second aspect of this disclosure is based on this realization.

[0020] [1] A rust-preventive film comprising at least recycled polyethylene, a vaporizable rust inhibitor, and an antioxidant.

[0021] The above-mentioned vaporizable rust inhibitors are selected from carboxylic acid esters and heterocyclic aromatic compounds.

[0022] The antioxidants mentioned above are phenolic antioxidants.

[0023] [2] The rust-preventive film described in [1] contains the above-mentioned vaporizable rust inhibitor in a proportion of 2 to 10% by mass relative to recycled polyethylene.

[0024] [3] The anti-rust film according to [1] or [2] contains the antioxidant at a ratio of 500 to 5000 ppm relative to the recycled polyethylene described above.

[0025] [4] The anti-rust film according to any one of [1] to [3] comprises a first layer containing at least recycled polyethylene, a vaporizable rust inhibitor, and an antioxidant, and a second layer containing polyethylene.

[0026] The polyethylene constituting the second layer is selected from at least one type of recycled polyethylene and virgin polyethylene.

[0027] The first layer and the second layer are formed by co-extrusion film formation.

[0028] [5] According to the rust-preventive film described in [4], the recycled polyethylene has a density of 0.860 g / cm³. 3 Above and 0.932 g / cm 3 The following polyethylene.

[0029] [6] A rust-preventive film comprising at least a first layer containing virgin polyethylene and a vaporizable rust inhibitor, and a second layer containing recycled polyethylene and an antioxidant.

[0030] The first layer and the second layer are formed by co-extrusion film formation.

[0031] [7] According to the anti-rust film described in [6], the antioxidant mentioned above is a phenolic antioxidant.

[0032] [8] According to the rust-preventive film described in [6] or [7], wherein the vaporizable rust inhibitor is selected from at least one of carboxylic acid ester rust inhibitors, alkanolamine rust inhibitors and heterocyclic aromatic compounds.

[0033] [9] The rust-proof film according to any one of [6] to [8], wherein the second layer further comprises virgin polyethylene.

[0034]

[10] The rust-preventive film according to any one of [6] to [9], wherein the above-mentioned vaporizable rust inhibitor is contained in a proportion of 2 to 10% by mass relative to the virgin polyethylene of the first layer.

[0035]

[11] The anti-rust film according to any one of [6] to

[10] , wherein the antioxidant is contained in a proportion of 500 to 5000 ppm relative to the polyethylene constituting the second layer.

[0036]

[12] According to any one of [6] to

[11] , the rust-preventive film wherein the polyethylene constituting the first layer is a polyethylene with a density of 0.860 g / cm³. 3 Above and 0.932 g / cm 3 The following polyethylene.

[0037]

[13] The rust-preventive film according to any one of [6] to

[12] further comprises a third layer formed of polyethylene.

[0038] The first layer, the second layer, and the third layer are formed by co-extrusion film formation.

[0039]

[14] A rust-preventive film comprising a first layer, a second layer, and a third layer,

[0040] The first layer mentioned above contains a vaporizable rust inhibitor and a density of 0.860 g / cm³. 3 Above and 0.932 g / cm 3 The following polyethylene,

[0041] The second layer mentioned above contains recycled polyethylene.

[0042] The third layer described above contains polyethylene with the same or higher density than the polyethylene constituting the first layer.

[0043] The first layer, the second layer, and the third layer are formed by co-extrusion film formation.

[0044]

[15] According to any one of [5],

[12] and

[14] , the rust-preventive film comprising the first layer has a density of 0.860 g / cm³. 3 Above and 0.932 g / cm 3 The polyethylene described below is selected from at least one of low-density polyethylene and linear low-density polyethylene.

[0045]

[16] According to the rust-preventive film described in

[14] , the vaporizable rust inhibitor is at least one selected from carboxylic acid ester rust inhibitors and alkanolamine rust inhibitors.

[0046]

[17] According to the rust-preventive film described in

[14] or

[16] , wherein the first layer contains 2 to 10% by mass of the above-mentioned vaporizable rust inhibitor.

[0047]

[18] The anti-rust film according to any one of

[14] ,

[16] and

[17] , wherein the second layer has a thickness of 2 to 4 times that of the first layer.

[0048]

[19] The rust-preventive film according to any one of

[14] and

[16] to

[18] , wherein the second layer comprises recycled polyethylene and virgin polyethylene.

[0049]

[20] The anti-rust film according to any one of

[14] and

[16] to

[19] , wherein the density constituting the first layer is 0.860 g / cm³. 3 Above and 0.932 g / cm 3 The following polyethylene is selected from at least one of virgin polyethylene and recycled polyethylene.

[0050] Invention Effects

[0051] According to this disclosure, a rust-preventive film that still has excellent rust-preventive effect while using recycled resin can be provided. Attached Figure Description

[0052] Figure 1 This is a schematic cross-sectional view showing one embodiment of the anti-rust film of this disclosure.

[0053] Figure 2 This is a schematic cross-sectional view showing one embodiment of the anti-rust film of this disclosure.

[0054] Figure 3 This is a schematic cross-sectional view showing one embodiment of the anti-rust film of this disclosure.

[0055] Figure 4 These are the GC-MS results of the resin compositions of Example 1 and Comparative Example 1.

[0056] Figure 5 The results are GC-MS measurements of the resin compositions of Example 1 and Comparative Example 2.

[0057] Figure 6 The results are GC-MS measurements of the resin compositions of Example 3 and Comparative Example 3.

[0058] Figure 7 The results are GC-MS measurements of the resin compositions of Example 4 and Comparative Example 4.

[0059] Figure 8 These are photographs of the appearance of the iron plate surface when evaluating the rust prevention properties of the rust-preventive films of Examples 7-10 and Comparative Example 5. Detailed Implementation

[0060] In this specification, when multiple upper limit values ​​and multiple lower limit values ​​are given for a certain parameter, the numerical range of that parameter can also be constructed by combining any one of the upper limit value candidates and any one of the lower limit value candidates. As an example, the statement "Parameter B is preferably A1 or higher, more preferably A2 or higher, and even more preferably A3 or higher. Parameter B is preferably A4 or lower, more preferably A5 or lower, and even more preferably A6 or lower" will be explained. In this example, the numerical range of parameter B can be A1 or higher and A4 or lower, or A1 or higher and A5 or lower, or A1 or higher and A6 or lower, or A2 or higher and A4 or lower, or A2 or higher and A5 or lower, or A2 or higher and A6 or lower, or A3 or higher and A4 or lower, or A3 or higher and A5 or lower, or A3 or higher and A6 or lower.

[0061] In this specification, polyethylene refers to a polymer in which the proportion of ethylene-derived structural units in the total amount of polymerizable monomer-derived structural units is greater than 50 mol%. In this polymer, the proportion of ethylene-derived structural units is preferably 70 mol% or more, more preferably 80 mol% or more, further preferably 90 mol% or more, and particularly preferably 95 mol% or more. The above-mentioned proportions are determined by nuclear magnetic resonance spectrophotometry (NMR).

[0062] In this specification, polyethylene can be a homopolymer of ethylene or a copolymer of ethylene and an olefinically unsaturated monomer other than ethylene. Examples of olefinically unsaturated monomers other than ethylene include α-olefins with 3 or more carbon atoms and less than 20, such as propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, 3-methyl-1-butene, 4-methyl-1-pentene, and 6-methyl-1-heptene; vinyl monomers such as vinyl acetate and vinyl propionate; and (meth)acrylates such as methyl (meth)acrylate and ethyl (meth)acrylate.

[0063] In this specification, examples of polyethylene include high-density polyethylene, medium-density polyethylene, low-density polyethylene and linear low-density polyethylene, as well as ethylene-vinyl acetate copolymer and ethylene-(meth)acrylate copolymer.

[0064] The density of polyethylene in this specification is shown below.

[0065] The density of low-density polyethylene is 0.860 g / cm³. 3 Above and 0.932 g / cm 3 The following is more preferably 0.900 g / cm³. 3 Above and 0.932 g / cm 3 the following.

[0066] The density of linear low-density polyethylene is 0.860 g / cm³. 3 Above and 0.932 g / cm 3 The following is more preferably 0.900 g / cm³. 3 Above and 0.932 g / cm 3 the following.

[0067] Medium-density polyethylene has a density greater than 0.932 g / cm³. 3 And it is 0.945 g / cm³ 3 the following.

[0068] High-density polyethylene has a density greater than 0.945 g / cm³. 3 And preferably 0.965 g / cm³ 3 the following.

[0069] The density of polyethylene was determined according to JIS K7112-2:2023 (density gradient tube method, 23℃).

[0070] Low-density polyethylene (LDPE) is, for example, polyethylene obtained by polymerizing ethylene through high-pressure polymerization (high-pressure LDPE). Linear LDPE is, for example, polyethylene obtained by polymerizing ethylene and a small amount of α-olefins using a polymerization method employing multi-site catalysts such as Ziegler-Natta catalysts or single-site catalysts such as metallocene catalysts.

[0071] Polyethylenes with different densities or branching can be obtained by appropriately selecting polymerization methods. For example, it is preferable to use multi-site catalysts such as Ziegler-Natta catalysts or single-site catalysts such as metallocene catalysts as polymerization catalysts, and to carry out polymerization in one or more stages by any of the following methods: gas-phase polymerization, slurry polymerization, solution polymerization, and high-pressure ionic polymerization.

[0072] The melt flow rate (MFR) of polyolefins such as polyethylene described in this specification is as follows. From the viewpoint of film-forming properties and processability, the MFR is preferably 0.1 g / 10 min or more, more preferably 0.3 g / 10 min or more, further preferably 0.5 g / 10 min or more, and preferably 30 g / 10 min or less, more preferably 20 g / 10 min or less, further preferably 10 g / 10 min or less, and particularly preferably 5 g / 10 min or less. For example, the MFR is 0.1 g / 10 min or more and 30 g / 10 min or less. The MFR of the polyolefin is determined by Method A under a load of 2.16 kg according to JIS K7210-1:2014. The measurement temperature of the MFR is set according to the melting point of the polyolefin, etc., and is 190°C in the case of polyethylene.

[0073] In this specification, as polyethylene, a resin material derived from biomass (hereinafter also referred to as "biomass polyethylene") can be used. Biomass material is, for example, a resin material obtained by using at least a portion of biomass-derived raw materials (specifically, plant-derived raw materials) as raw materials. Since biomass materials are carbon-neutral, they can reduce the environmental burden.

[0074] In this specification, "recycled polyethylene" refers to polyethylene obtained from used polyethylene products through mechanical or chemical recycling. Mechanical recycling typically involves crushing the recycled polyethylene film, performing alkaline cleaning to remove surface dirt and foreign matter, and then drying it under high temperature and reduced pressure for a certain period to allow residual contaminants inside the film to diffuse and be removed, thus clearing the film and restoring it to polyethylene. Chemical recycling typically involves breaking down the recycled polyethylene film to the monomer level, allowing the monomers to be polymerized again to obtain polyethylene. Furthermore, in this specification, "virgin polyethylene" refers to polyethylene obtained from fossil fuel-derived or biomass-derived raw materials, rather than recycled polyethylene.

[0075] The embodiments of this disclosure will now be described in detail. This disclosure can be implemented in many different ways and is not limited to the description of the embodiments illustrated below. To make the description clearer, the drawings sometimes schematically show the width, thickness, and shape of each layer compared to the embodiments; however, this is only an example and does not limit the interpretation of this disclosure. In this specification and the drawings, the same symbols are sometimes used for elements that are the same as those described with respect to previously shown figures, and detailed descriptions are appropriately omitted.

[0076] <Method 1>

[0077] Hereinafter, embodiments of the rust-preventive film of the first aspect of this disclosure will be described with appropriate use of the accompanying drawings.

[0078] Figure 1 This is a schematic cross-sectional view illustrating one embodiment of the rust-preventive film of the first aspect of this disclosure. The rust-preventive film 1 of one embodiment of this disclosure is formed from a first layer 10 comprising at least recycled polyethylene, a vaporizable rust inhibitor, and an antioxidant. Figure 2 and Figure 3 This is a schematic cross-sectional view illustrating another embodiment of the rust-preventive film according to the first aspect of this disclosure. The rust-preventive film 1 of the other embodiment of the rust-preventive film according to the first aspect of this disclosure may be configured to have a first layer 10 and a second layer 20. The first layer 10 contains at least recycled polyethylene, a vaporizable rust inhibitor, and an antioxidant, and the second layer 20 contains at least one selected from recycled polyethylene and virgin polyethylene. Furthermore, in addition to the second layer, as shown in the diagram... Figure 3The embodiment further comprises a third layer 30 containing at least one material selected from recycled polyethylene and virgin polyethylene. It should be noted that... Figure 2 and Figure 3 In the rust-preventive film 1 of the first aspect of this disclosure, the first layer 10 containing a vaporizable rust inhibitor forms the innermost layer when the rust-preventive film is used as a packaging for metal parts, etc. Furthermore, in Figure 2 In the rust-preventive film 1 of the first embodiment of this disclosure, the second layer 20 is the outermost layer when used as a packaging body. Furthermore, in Figure 3 In the rust-preventive film 1 of the first aspect of this disclosure, the third layer 30 is the innermost layer when the rust-preventive film is used as a packaging body for metal parts, etc., and the second layer 20 is an intermediate layer provided between the first layer 10, which is the innermost layer, and the third layer 30, which is the outermost layer. Hereinafter, each layer constituting the rust-preventive film 1 of the first aspect of this disclosure will be described.

[0079] The rust-preventive film of the first aspect of this disclosure is as follows Figure 1 In the case shown, where the structure is a single layer, the layer contains at least recycled polyethylene, a vapor-induced rust inhibitor, and an antioxidant. Recycled polyethylene, especially mechanically recycled polyethylene, is manufactured by remelting used polyethylene as shown above. To prevent thermal degradation of the polyethylene, an antioxidant is sometimes added. The antioxidant captures free radicals generated by the thermal decomposition of the polyethylene during remelting, thereby inhibiting the cleavage and cross-linking reactions of the polyethylene molecular chains. On the other hand, this antioxidant sometimes deactivates the vapor-induced rust inhibitor. In vapor-induced rust inhibitors, particularly carboxylic esters and heterocyclic aromatic compounds, deactivation due to amine-based antioxidants is significant. Furthermore, in vapor-induced rust inhibitors, amine-based rust inhibitors have a similar chemical structure to amine-based antioxidants. Therefore, even when used as a vapor-induced rust inhibitor, the heat during film formation causes them to act as antioxidants (free radical scavengers), resulting in a reduced rust-preventive effect of the resulting rust-preventive film. In the first aspect of this disclosure, by using a phenolic antioxidant as an antioxidant and a carboxylic acid ester-based rust inhibitor or a heterocyclic aromatic compound as a vaporization rust inhibitor, the reduction in rust-preventive effect during the formation of the rust-preventive film is suppressed. By using this specific vaporization rust inhibitor in combination with a specific antioxidant, a rust-preventive film that still exhibits excellent rust-preventive effect while reducing environmental impact can be achieved.

[0080] The rust-preventive film of the first aspect of this disclosure is as follows Figure 1In the case where the structure is a single layer, the layer contains recycled polyethylene as the main component, which is the resin component. In this disclosure, "a layer containing recycled polyethylene as the main component" means a layer in which the proportion of recycled polyethylene in 100% by mass is 50% or more. The aforementioned proportion is preferably 60% by mass or more, more preferably 70% by mass or more, further preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more.

[0081] The preferred density of recycled polyethylene is 0.860 g / cm³. 3 Above and 0.932 g / cm 3 The following describes the appropriate types of polyethylene within this density range. Low-density polyethylene and linear low-density polyethylene can be used, with linear low-density polyethylene being more preferred. As an example, a density of 0.900 g / cm³ is more preferred. 3 Above and 0.932 g / cm 3 The following is linear low-density polyethylene.

[0082] Furthermore, when the resin component includes both recycled polyethylene and virgin polyethylene, it is preferable that the density of the virgin polyethylene is 0.860 g / cm³. 3 Above and 0.932 g / cm 3 Linear low-density polyethylene may be preferred in the following cases. For example, a density of 0.900 g / cm³ is preferred. 3 Above and 0.932 g / cm 3 The following is linear low-density polyethylene.

[0083] The rust-preventive film of the first aspect of this disclosure is as follows Figure 1 In the case shown, which is composed of a single layer, a phenolic antioxidant is included in addition to the recycled polyethylene that constitutes the layer. Examples of phenolic antioxidants include octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and pentaerythritol tetra[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]. Commercially available phenolic antioxidants can also be used, such as 3,3',3”, 5,5',5”-hexa-tert-butyl-α,α',α”-(trimethylbenzene-2,4,6-trimethyl)tri-p-cresol (BASF IRGANOX 1330) and 3,9-bis{2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1-dimethylethyl}-2,4,8,10-tetraoxaspiro[5.5]undecane (ADEKA, Adekastab AO-80), etc.

[0084] Phenolic antioxidants can be used to form rust-preventive films by mixing them into recycled polyethylene, or they can be added to used polyester during mechanical recycling and remelting. In other words, recycled polyester can contain phenolic antioxidants in advance.

[0085] Preferably, the recycled polyethylene contains a phenolic antioxidant at a ratio of 500 to 5000 ppm, more preferably 1000 to 4000 ppm. It should be noted that the inclusion of phenolic antioxidants used in the manufacture of the recycled polyethylene is not excluded; conventionally used antioxidants (phosphate-based, sulfur-based, amine-based, etc.) may be included in the recycled polyethylene. Furthermore, when the rust-preventive film described later is multilayered, the recycled polyethylene in the layer containing the vaporizable rust inhibitor preferably contains it at a ratio of 500 ppm, more preferably 1000 to 4000 ppm.

[0086] In addition, if the product contains both recycled polyethylene and virgin polyethylene, phenolic antioxidants may be used in the manufacture of virgin polyethylene. In this case, the content of phenolic antioxidants is set as the sum of the phenolic antioxidants contained in the recycled polyethylene and virgin polyethylene, and the phenolic antioxidants added when manufacturing the anti-rust film.

[0087] Among vapor-induced rust inhibitors that exhibit rust-preventive effects by volatilizing at 40℃ to 60℃ (such as ammonium salts of aliphatic or aromatic acids, nitrites of amines, carboxylates of amines, chromates of amines, esters of carboxylic acids, heterocyclic compounds, thioureas, mercapto-containing compounds, triazole rings, pyrrole rings, pyrazole rings, thiazole rings, imidazole rings, and other heterocyclic compounds), carboxylic acid esters and heterocyclic aromatic compounds that can inhibit the reduction in rust-preventive effects caused by phenolic antioxidants are used.

[0088] As a carboxylic acid ester-based rust inhibitor, fatty acid esters are preferred. The fatty acid moiety of the fatty acid ester preferably has 6 or more and 20 or fewer carbon atoms. If the number of carbon atoms is less than this range, the boiling point may be too close to the film-forming temperature, potentially resulting in bubble formation or failure to form a film. Specific examples of fatty acid esters include alcohol esters and glycerol fatty acid esters of the aforementioned fatty acids; glycerol fatty acid esters are preferably triglyceride esters, and more preferably triglyceride caprylate. Among the aforementioned fatty acids, one or more selected from heptanoic acid, octanoic acid, decanoic acid, lauric acid, stearic acid, caprylic acid, capric acid, calcium stearate, and triglyceride caprylate are preferred.

[0089] Examples of heterocyclic aromatic compounds include those having triazole, pyrrole, pyrazole, thiazole, or imidazole rings, with compounds having triazole rings and benzoate compounds being particularly preferred. More specifically, examples of rust inhibitors having triazole rings include benzotriazole (BTA) and methylbenzotriazole (TTA). Furthermore, examples of benzoate compounds include monoethanolamine benzoate (MEA•BA), dicyclohexammonium benzoate (DICHA•BA), and diisopropylammonium benzoate (DIPA•BA).

[0090] Regarding the amount of vaporizable rust inhibitor added, from the viewpoint of rust inhibitor release and resin extrusion film-forming properties, it is preferable to add it at a ratio of 0.1% to 30% by mass relative to the recycled polyethylene constituting the layer containing the vaporizable rust inhibitor; more preferably, at a ratio of 0.5% to 20% by mass; and even more preferably, at a ratio of 2% to 10% by mass. It should be noted that when the layer containing the vaporizable rust inhibitor includes both recycled polyethylene and virgin polyethylene as resin components, it is preferable to add it at a ratio of 0.1% to 30% by mass relative to the total amount of recycled polyethylene and virgin polyethylene; more preferably, at a ratio of 0.5% to 20% by mass; and even more preferably, at a ratio of 2% to 10% by mass.

[0091] The rust-preventive film of the first aspect of this disclosure is as follows Figure 1 In the case of a single layer, the thickness of the anti-rust film can be appropriately determined according to the application. However, from the viewpoint of the diffusion of vaporizable rust inhibitors, it is generally 50 μm or more, more preferably 60 μm or more, even more preferably 80 μm or more, and generally 150 μm or less, more preferably 120 μm or less, and even more preferably 100 μm or less.

[0092] The following describes an embodiment of the first aspect of this disclosure where the anti-rust film is multi-layered. For example... Figure 2 and Figure 3 As shown, the rust-preventive film of the first aspect of this disclosure may have a second layer in addition to the layer containing the vaporizable rust inhibitor (first layer), and may further have a third layer in addition to the second layer. The second layer and / or the third layer constitute the outermost layer when the rust-preventive film is used as packaging for metal parts, etc. By having the rust-preventive film as an outermost layer, the diffusion of the vaporizable rust inhibitor contained in the first layer into the atmosphere outside the rust-preventive film can be suppressed. In addition, the puncture resistance is improved compared to a single-layer film. Therefore, even when the packaging has metal mechanical components such as protrusions, the rust-preventive film according to the first aspect of this disclosure can suppress breakage caused by mechanical components.

[0093] When the rust-preventive film is multilayered, the layer containing the vaporizable rust inhibitor (the first layer) can be configured with the same structure as the single layer described above. Furthermore, regarding the first layer when the rust-preventive film is multilayered, from the viewpoint of the diffusion properties of the vaporizable rust inhibitor, it is preferably 3 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more. From the viewpoint of film-forming properties and processability, it is preferably 60 μm or less, more preferably 40 μm or less, and even more preferably 30 μm or less. The thickness of the first layer is, for example, 10 to 30 μm.

[0094] When the second and / or third layer is the outermost layer, the main component of the resin is polyethylene with the same or higher density as the polyethylene constituting the layer containing the vaporizable rust inhibitor (first layer). For example, if the polyethylene constituting the first layer is low-density polyethylene or linear low-density polyethylene, the outermost layer can use low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, or high-density polyethylene.

[0095] The second layer, located on the outer side of the first layer, can be formed from at least one of recycled polyethylene and virgin polyethylene; however, from the viewpoint of reducing environmental burden, it is preferred to form it from recycled polyethylene. Recycled polyethylene (especially mechanically recycled polyethylene) is a material formed by mixing various types of polyethylene (low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, and other polyethylenes) that have been used during recycling. However, considering film-forming properties and processability, it is preferable to use recycled polyethylene with an MFR of 0.1 g / 10 min or more and 30 g / 10 min or less.

[0096] The second layer may contain virgin polyethylene in addition to recycled polyethylene. By appropriately adding virgin polyethylene, film-forming properties and processability can be improved. When the second layer contains both recycled and virgin polyethylene, the content of virgin polyethylene relative to the entire second layer is preferably greater than 0% by mass and less than 50% by mass, more preferably more than 15% by mass and less than 35% by mass.

[0097] When the second layer contains virgin polyethylene, the virgin polyethylene is preferably 0.860 g / cm³. 3 Above and 0.932 g / cm 3 The following low-density polyethylene, more preferably 0.900 g / cm³, is preferred. 3 Above and 0.932 g / cm 3 The following low-density polyethylene, or preferably 0.860 g / cm³. 3 Above and 0.932 g / cm 3 The following linear low-density polyethylene, more preferably 0.900 g / cm³, is preferred. 3 Above and 0.932 g / cm 3The following is linear low-density polyethylene.

[0098] Regarding the thickness of the second layer, from the viewpoint of reducing environmental burden, it is preferably 20 μm or more, more preferably 30 μm or more, and even more preferably 40 μm or more. From the viewpoint of film-forming properties and processability, it is preferably 80 μm or less, more preferably 70 μm or less, and even more preferably 60 μm or less. The thickness of the second layer is, for example, 40 to 60 μm.

[0099] Furthermore, the second layer preferably has a thickness of 2 to 4 times that of the layer containing the vaporizable rust inhibitor (the first layer). When using recycled polyethylene, the melting temperature during film formation needs to be slightly higher than that of virgin polyethylene (around 200 to 210°C). However, when forming the first and second layers (or even the third layer) using a blow molding co-extrusion film-forming method, by setting the thickness of the second layer to 2 to 4 times that of the first layer, it is possible to impart sufficient heat for the recycled polyethylene to melt during extrusion film formation while simultaneously air-cooling the surface of the innermost first layer. This helps to suppress the thermal degradation and volatilization of the vaporizable rust inhibitor in the first layer. More preferably, the second layer has a thickness of 2 to 3 times that of the first layer.

[0100] When adding a third layer on top of the second layer, from the viewpoint of suppressing the diffusion of vaporized rust inhibitors, it is preferable to use high-density polyethylene as the polyethylene constituting the third layer. However, from the viewpoints of film-forming properties during rust film formation and suppressing the curling of the resulting film, the polyethylene should be selected in a way that does not increase the density difference between the polyethylene constituting the first layer and the polyethylene constituting the third layer. From the viewpoints of suppressing the diffusion of vaporized rust inhibitors and suppressing curling, it is preferable to use low-density polyethylene or linear low-density polyethylene with a density that is the same as or higher than that of the polyethylene constituting the first layer.

[0101] Furthermore, either virgin polyethylene or recycled polyethylene can be used as the polyethylene constituting the third layer. From the viewpoint of reducing environmental burden, it can be said that recycled polyethylene is also preferred for the third layer. However, as mentioned above, from the viewpoint of suppressing the diffusion of vaporized rust inhibitors and suppressing curling, it is preferable to use virgin polyethylene (low-density polyethylene or linear low-density polyethylene) with the same or higher density as the polyethylene constituting the first layer.

[0102] Regarding the thickness of the third layer, from the viewpoint of suppressing the diffusion of vaporized rust inhibitors, it is preferably 3 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more. From the viewpoint of film-forming properties and processability, it is preferably 60 μm or less, more preferably 40 μm or less, and even more preferably 30 μm or less. The thickness of the third layer is, for example, 10 to 30 μm.

[0103] It should be noted that when recycled polyethylene is used in the second and / or third layers, phenolic antioxidants can be added during the manufacture of the anti-rust film, in addition to the antioxidants contained in the manufacture of the recycled polyethylene. The amount of phenolic antioxidant added relative to the recycled polyethylene is preferably 500 to 5000 ppm, more preferably 1000 to 4000 ppm.

[0104] When the anti-rust film of the first aspect of this disclosure is multilayered, the total thickness can also be appropriately adjusted according to the application, and is approximately 50 μm or more, more preferably 60 μm or more, even more preferably 80 μm or more, and approximately 150 μm or less, more preferably 120 μm or less, and even more preferably 100 μm or less.

[0105] [Manufacturing method of anti-rust film]

[0106] In the case where the rust-preventive film of the first aspect of this disclosure is a single layer, recycled polyethylene, vaporizable rust inhibitor and antioxidant can be mixed and obtained by blow molding with an annular die, extrusion molding with a T-die, etc.

[0107] In the case of producing a multi-layered rust-preventive film, it can be obtained by co-extruding a layer containing a vaporizable rust inhibitor (layer 1) with other layers (layer 2 or layer 3). Co-extrusion film formation can be achieved using known film-forming methods such as blow molding co-extrusion and co-extrusion film formation. Among these methods, blow molding co-extrusion film formation can be carried out at a lower temperature, such as below 200°C, thus suppressing the thermal decomposition and volatilization (vaporization) of the vaporizable rust inhibitor during film formation.

[0108] During film formation, the components can be mixed simultaneously, or a masterbatch consisting of recycled polyethylene, a vaporizable rust inhibitor, and an antioxidant can be prepared in advance, and then the recycled polyethylene can be mixed with the masterbatch to form a film. In particular, to improve the dispersibility of the vaporizable rust inhibitor, a masterbatch containing the vaporizable rust inhibitor can be used, and a material blended with the recycled polyethylene can be co-extruded to form a film. There are no particular restrictions on the proportion of the vaporizable rust inhibitor in the masterbatch, as long as the proportion of the vaporizable rust inhibitor in the layer containing the vaporizable rust inhibitor (first layer) is within the range described above, and the masterbatch is blended with polyethylene of a given density.

[0109] <Method 2>

[0110] Hereinafter, embodiments of the rust-preventive film of the second aspect of this disclosure will be described with appropriate use of the accompanying drawings.

[0111] Figure 2This is a schematic cross-sectional view illustrating one embodiment of the rust-preventive film of the second aspect of this disclosure. The rust-preventive film 1 of one embodiment of the rust-preventive film of the second aspect of this disclosure has a multilayer structure comprising at least a first layer 10 containing virgin polyethylene and a vaporizable rust inhibitor, and a second layer 20 containing recycled polyethylene and an antioxidant. Figure 3 This is a schematic cross-sectional view illustrating another embodiment of the rust-preventive film according to the second aspect of this disclosure. The rust-preventive film 1 of this second aspect of the rust-preventive film has a multilayer structure comprising a first layer 10 containing virgin polyethylene and a vaporizable rust inhibitor, a second layer 20 containing recycled polyethylene and an antioxidant, and a third layer 30 formed of polyethylene. It should be noted that the first layer containing the vaporizable rust inhibitor is the innermost layer when the rust-preventive film is used as packaging for metal parts, etc. Figure 2 In the rust-preventive film 1 of the second aspect of this disclosure, the second layer 20 is the outermost layer when used as a packaging body. Furthermore, in Figure 3 In the rust-preventive film 1 of the second aspect of this disclosure, the third layer 30 is the innermost layer when the rust-preventive film is used as a packaging body for metal parts, etc., and the second layer 20 is an intermediate layer provided between the first layer 10, which is the innermost layer, and the third layer 30, which is the outermost layer. Hereinafter, each layer constituting the rust-preventive film 1 of the second aspect of this disclosure will be described.

[0112] [Level 1]

[0113] The first layer of the rust-preventive film constituting the second aspect of this disclosure is a layer containing virgin polyethylene as the main component of the resin. In this disclosure, "a layer containing polyethylene as the main component" means a layer in which the proportion of virgin polyethylene in 100% by mass is 50% or more. The aforementioned proportion is preferably 60% by mass or more, more preferably 70% by mass or more, further preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more.

[0114] From the perspective of reducing environmental burden, recycled polyethylene is preferred over virgin polyethylene. However, recycled polyethylene, especially mechanically recycled polyethylene, is a material manufactured by remelting used polyethylene as described above. In this case, antioxidants are sometimes added to prevent the thermal degradation of polyethylene. Antioxidants inhibit the breaking of polyethylene molecular chains and cross-linking reactions by capturing free radicals generated by the thermal decomposition of polyethylene during remelting. On the other hand, such antioxidants can sometimes deactivate vaporizable rust inhibitors. As a result, the rust-preventive effect of the resulting rust-preventive film is reduced. In the second aspect of this disclosure, a layer formed from recycled polyethylene containing an antioxidant is designated as the second layer, and virgin polyethylene with a low antioxidant content is used as the resin component constituting the first layer containing a vaporizable rust inhibitor. This allows for the creation of a rust-preventive film that maintains excellent rust-preventive effect while reducing environmental burden.

[0115] The preferred density of the virgin polyethylene used in the first layer is 0.860 g / cm³. 3 Above and 0.932 g / cm 3 As described above, low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE) can be used appropriately, and linear LLDPE is more preferably used. As the resin component constituting the first layer, a density of 0.900 g / cm³ is more preferably used. 3 Above and 0.932 g / cm 3 The following is linear low-density polyethylene.

[0116] The first layer of the rust-preventive film constituting the second aspect of this disclosure comprises a vaporizable rust inhibitor. The first layer can be formed by mixing the vaporizable rust inhibitor into polyethylene of a given density, which is a resin component, and then forming a film.

[0117] As vapor-induced rust inhibitors, conventionally known vapor-induced rust inhibitors that exhibit rust-preventive effects by volatilizing at 40°C to 60°C can be used without particular restriction. Examples include various ammonium salts of aliphatic or aromatic acids, nitrites of amines, carboxylates of amines, chromates of amines, esters of carboxylic acids, heterocyclic compounds, thioureas, mercapto-containing compounds, triazole rings, pyrrole rings, pyrazole rings, thiazole rings, imidazole rings, and other heterocyclic compounds. Among these, from an environmental adaptability point of view, carboxylic acid esters, alkanolamines, and heterocyclic aromatic compounds can be appropriately used.

[0118] The characteristics of carboxylic acid ester-based rust inhibitors are as described in Method 1.

[0119] Examples of alkanolamine-based rust inhibitors include dicyclohexylamine, monoethanolamine, diethanolamine, diisopropylamine, cyclohexylamine, nitronaphthylamine, ammonium benzoate (ammonium benzoate), cyclohexylammonium benzoate, cyclohexylammonium carbamate, cyclohexylammonium nitrite, cyclohexylammonium octanoate, cyclohexylammonium laurate, dicyclohexylammonium benzoate, dicyclohexylammonium carbamate, isopropylammonium nitrite, isopropylammonium octanoate, isopropylammonium laurate, isopropylammonium benzoate, isopropylammonium carbamate, diisopropylammonium nitrite, diisopropylammonium octanoate, diisopropylammonium laurate, diisopropylammonium benzoate, diisopropylammonium carbamate, benzylammonium nitrite, benzylammonium octanoate, benzylammonium laurate, benzylammonium benzoate, benzylammonium carbamate, dibenzylammonium nitrite, dibenzylammonium octanoate, dibenzylammonium laurate, dibenzylammonium benzoate, dibenzylammonium carbamate, etc.

[0120] The characteristics of heterocyclic aromatic compounds are as described in Method 1.

[0121] Regarding the amount of vaporizable rust inhibitor added, from the viewpoint of the release properties of the rust inhibitor and the extrusion film-forming properties of the resin, it is preferable to add it at a ratio of 0.1% or more and 30% or less by mass relative to the virgin polyethylene constituting the first layer, more preferably at a ratio of 0.5% or more and 20% or less by mass, and even more preferably at a ratio of 2% or more and 10% or less by mass.

[0122] The thickness of the first layer constituting the rust-preventive film is as described in the first method when the rust-preventive film is multi-layered.

[0123] [Level 2]

[0124] The second layer of the rust-preventive film constituting the second aspect of this disclosure is an outer layer of the first layer (the outermost layer when the rust-preventive film is used as packaging for metal parts, etc.), and contains recycled polyethylene as the main component of the resin. By using recycled polyethylene, environmental burden can be reduced. As mentioned above, while recycled polyethylene, especially mechanically recycled polyethylene, can suppress thermal degradation by containing antioxidants, it can sometimes deactivate vaporizable rust inhibitors. However, the rust-preventive film of the second aspect of this disclosure, by utilizing recycled polyethylene to form a second layer different from the first layer containing vaporizable rust inhibitors, can achieve excellent rust prevention while reducing environmental burden. Furthermore, compared to virgin polyethylene resin, recycled polyethylene contains impurities and various purity grades of polyethylene. If recycled polyethylene is used as the main component as the resin constituting the outermost, first layer, the film-forming temperature needs to be increased. It is also known that recycled polyethylene, compared to virgin polyethylene, produces fisheyes, wrinkles, etc., during film formation. In the second aspect of this disclosure, by making the anti-rust film consist of two layers and using recycled polyethylene as the second layer, it is possible to reduce the environmental burden while eliminating the problems mentioned above.

[0125] Recycled polyethylene (especially mechanically recycled polyethylene) is a material made by blending various types of used polyethylene (low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, and other polyethylenes) during recycling. However, considering film-forming properties and processability, recycled polyethylene with an MFR of 0.1 g / 10 min or higher and 30 g / 10 min or lower is preferred.

[0126] The second type of rust-preventive film disclosed herein may include virgin polyethylene in addition to recycled polyethylene as a second layer. The characteristics of the virgin polyethylene that may be included in the second layer are as described in the first type.

[0127] In the second layer, which contains recycled polyethylene as the main component, an antioxidant is included to prevent thermal degradation of the polyethylene. Conventionally known antioxidants such as phenolic, phosphoric acid, sulfur-based, and amine-based antioxidants can be used; however, from the viewpoint of rust prevention, an antioxidant such as dicyclohexylamine is preferred.

[0128] The characteristics of phenolic antioxidants are as described in Method 1.

[0129] The thickness of the second layer is as described in Method 1.

[0130] Furthermore, the second layer preferably has a thickness of 2 to 4 times that of the first layer containing the vaporizable rust inhibitor. The reason for this is as described in the first embodiment. More preferably, the second layer has a thickness of 2 to 3 times that of the first layer.

[0131] [Level 3]

[0132] The rust-preventive film of the second aspect of this disclosure may include a third layer in addition to the second layer. When the third layer is included, it is the outermost layer when the rust-preventive film is used as a packaging material for metal parts, etc. By including the third layer, the diffusion of the vaporized rust inhibitor contained in the first layer into the atmosphere outside the rust-preventive film can be suppressed. The resin component of the third layer is primarily polyethylene with a density equal to or higher than that of the polyethylene constituting the first layer. For example, if the polyethylene constituting the first layer is low-density polyethylene or linear low-density polyethylene, the outermost layer may use low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, or high-density polyethylene.

[0133] From the viewpoint of suppressing the diffusion of vaporized rust inhibitors, it is preferable to use high-density polyethylene as the polyethylene constituting the third layer. However, from the viewpoints of film-forming properties during rust inhibitor film formation and suppressing the curling of the resulting film, the polyethylene should be selected in a way that does not increase the density difference between the recycled polyethylene constituting the innermost first layer and the polyethylene constituting the outermost third layer. From the viewpoints of suppressing the diffusion of vaporized rust inhibitors and suppressing curling, it is preferable to use low-density polyethylene or linear low-density polyethylene with a density that is the same as or higher than that of the recycled polyethylene constituting the first layer.

[0134] Furthermore, either virgin polyethylene or recycled polyethylene can be used as the polyethylene constituting the third layer. From the viewpoint of reducing environmental burden, it can be said that recycled polyethylene is also preferred for the third layer. However, as mentioned above, from the viewpoint of suppressing the diffusion of vaporized rust inhibitors and suppressing curling, it is preferable to use virgin polyethylene (low-density polyethylene or linear low-density polyethylene) with the same or higher density as the recycled polyethylene constituting the first layer.

[0135] Regardless of whether the polyethylene constituting the third layer is virgin polyethylene or recycled polyethylene, it may contain the aforementioned phenolic antioxidants. Regarding the content of the phenolic antioxidants, it is preferably 500 to 5000 ppm relative to the polyethylene constituting the third layer, more preferably 1000 to 4000 ppm. It should be noted that the inclusion of phenolic antioxidants used in the manufacture of recycled polyethylene is not excluded; recycled polyethylene may also contain antioxidants (phosphate-based, sulfur-based, amine-based, etc.) that have been used historically.

[0136] The thickness of the third layer constituting the anti-rust film is as described in Method 1.

[0137] The total thickness of the rust-preventive film in the second aspect of this disclosure is as described in the first aspect when the rust-preventive film is multi-layered.

[0138] [Manufacturing method of anti-rust film]

[0139] The rust-preventive film of the second aspect of this disclosure can be obtained by co-extruding the first and second layers (or, in the case of a third layer, the first, second, and third layers) together. Co-extrusion can be performed using a blow molding co-extrusion method with an annular die or a T-die co-extrusion method. The blow molding co-extrusion method allows for melt co-extrusion at temperatures as low as 200°C, thus suppressing the thermal decomposition and volatilization (vaporization) of the volatile rust inhibitor during film formation. Particularly when using recycled polyethylene as the resin component of the second layer, it is necessary to have a slightly higher melt temperature during film formation than virgin polyethylene (around 200-210°C). However, the blow molding co-extrusion method allows the melt temperature of the virgin polyethylene in the first layer to be set below 200°C, and air cooling during film formation reduces the thermal impact on the first layer. As a result, a rust-preventive film with excellent rust-preventive properties can be obtained while using recycled resin. Furthermore, by producing a two- or three-layer co-extruded film of polyethylene as described in the second aspect of this disclosure, puncture resistance is improved compared to a single-layer film. Therefore, even in cases where the packaging contains protruding metal mechanical components, the rust-proof film according to the present invention can suppress breakage caused by these mechanical parts.

[0140] In forming the first layer, to improve the dispersibility of the vaporizable rust inhibitor, a masterbatch containing the vaporizable rust inhibitor can be used, and a material obtained by blending the masterbatch with polyethylene of a given density can be co-extruded into a film. There are no particular restrictions on the proportion of the vaporizable rust inhibitor in the masterbatch, as long as the masterbatch is blended with polyethylene of a given density in a manner that ensures the proportion of the vaporizable rust inhibitor in the first layer is within the aforementioned range.

[0141] <Third Method>

[0142] Hereinafter, embodiments of the rust-preventive film of the third aspect of this disclosure will be described with appropriate use of the accompanying drawings.

[0143] Figure 3 This is a schematic cross-sectional view illustrating one embodiment of the rust-preventive film according to the third aspect of this disclosure. The rust-preventive film 1 according to the third aspect of this disclosure is a film obtained by co-extrusion forming of at least a first layer 10, a second layer 20, and a third layer 30 in sequence. It should be noted that the term "in sequence" in the rust-preventive film means that the rust-preventive film 1 has each layer (first layer 10, second layer 20, and third layer 30) in sequence in the thickness direction of the rust-preventive film 1.

[0144] The first layer 10 of the rust-preventive film 1 of the third aspect of this disclosure is the innermost layer when the rust-preventive film is used as a packaging body for metal parts, etc., the third layer 30 is the third layer when used as a packaging body, and the second layer 20 is the layer provided between the first layer 10 and the third layer 30. Hereinafter, each layer constituting the rust-preventive film 1 of the third aspect of this disclosure will be described.

[0145] [Level 1]

[0146] The first layer of the rust-preventive film constituting the third aspect of this disclosure is a resin component with a density of 0.860 g / cm³. 3 Above and 0.932 g / cm 3 The following layer contains polyethylene as a main component. In this disclosure, "a layer containing polyethylene as a main component" means a layer in which the polyethylene content is 50% or more out of 100% by mass. The aforementioned content is preferably 60% or more by mass, more preferably 70% or more by mass, further preferably 80% or more by mass, even more preferably 90% or more by mass, and particularly preferably 95% or more by mass.

[0147] With a density of 0.860 g / cm³ 3 Above and 0.932 g / cm 3 The polyethylene used below can be, as described above, low-density polyethylene, linear low-density polyethylene, and more preferably linear low-density polyethylene. As the resin component constituting the first layer, a density of 0.900 g / cm³ is more preferably used. 3 Above and 0.932 g / cm 3 The following is linear low-density polyethylene.

[0148] With a density of 0.860 g / cm³ 3 Above and 0.932 g / cm 3 The polyethylene described below can be virgin polyethylene, or, from the perspective of reducing environmental burden, recycled polyethylene. Alternatively, it can be a mixture of virgin and recycled polyethylene. That is, it can be at least one type selected from virgin polyethylene and recycled polyethylene.

[0149] The first layer of the rust-preventive film constituting the third aspect of this disclosure comprises a vaporizable rust inhibitor. The first layer can be formed by mixing the vaporizable rust inhibitor into polyethylene of a given density, which is a resin component, and then forming a film.

[0150] Regarding the amount of vaporizable rust inhibitor added, from the viewpoint of the release properties of the rust inhibitor and the extrusion film-forming properties of the resin, it is preferable to add it at a ratio of 0.1% or more and 30% or less by mass relative to the entire first layer, more preferably at a ratio of 0.5% or more and 20% or less by mass, and even more preferably at a ratio of 2% or more and 10% or less by mass.

[0151] Other characteristics of vaporizable rust inhibitors are described in Method 2.

[0152] The thickness of the first layer constituting the rust-preventive film is as described in the first method when the rust-preventive film is multi-layered.

[0153] [Level 2]

[0154] The second layer of the rust-preventive film constituting the third aspect of this disclosure is a layer disposed between the first and third layers, and contains recycled polyethylene as the main component of the resin. By using recycled polyethylene, environmental burden can be reduced. As mentioned above, recycled polyethylene, especially mechanically recycled polyethylene, contains impurities and various purity grades of polyethylene compared to virgin polyethylene resin. If recycled polyethylene is used as the main component of the resin constituting the first and third layers, the film-forming temperature needs to be increased. Furthermore, it is known that recycled polyethylene, compared to virgin polyethylene, produces fisheyes, wrinkles, etc., during film formation. In the third aspect of this disclosure, by constructing a rust-preventive film with three layers and using recycled polyethylene as its second layer, environmental burden can be reduced while eliminating the problems mentioned above.

[0155] The second layer of the rust-preventive film constituting the third aspect of this disclosure may or may not contain an antioxidant. Other features of the second layer are as described in the second aspect.

[0156] [Level 3]

[0157] The third layer of the rust-preventive film of the third aspect of this disclosure is a layer constituting the third layer when the rust-preventive film is used as a packaging body for metal parts, etc. By having the rust-preventive film with a third layer, the diffusion of the vaporizable rust inhibitor contained in the first layer into the atmosphere outside the rust-preventive film can be suppressed. The resin component of the third layer is polyethylene with a density equal to or greater than that of the polyethylene constituting the first layer. For example, if the polyethylene constituting the first layer is low-density polyethylene or linear low-density polyethylene, the third layer can use low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, or high-density polyethylene.

[0158] From the viewpoint of suppressing the diffusion of vaporized rust inhibitors, it is preferable to use high-density polyethylene as the polyethylene constituting the third layer. However, from the viewpoints of film-forming properties during rust film formation and suppressing the curling of the resulting film, the polyethylene should be selected in a way that does not increase the density difference between the polyethylene constituting the innermost first layer and the polyethylene constituting the third layer. From the viewpoints of suppressing the diffusion of vaporized rust inhibitors and suppressing curling, low-density polyethylene or linear low-density polyethylene with the same or higher density as the polyethylene constituting the first layer is preferred.

[0159] Furthermore, either virgin polyethylene or recycled polyethylene can be used as the polyethylene constituting the third layer. From the viewpoint of reducing environmental burden, it can be said that recycled polyethylene is also preferred for the third layer. However, as mentioned above, from the viewpoint of suppressing the diffusion of vaporized rust inhibitors and suppressing curling, it is preferable to use virgin polyethylene (low-density polyethylene or linear low-density polyethylene) with the same or higher density as the polyethylene constituting the first layer.

[0160] The thickness of the third layer constituting the anti-rust film is as described in Method 1.

[0161] The total thickness of the rust-preventive film in the third aspect of this disclosure is as described in the first aspect when the rust-preventive film is multi-layered.

[0162] [Manufacturing method of anti-rust film]

[0163] The rust-preventive film of the third aspect of this disclosure can be obtained by co-extruded the aforementioned first, second, and third layers. Co-extruded film formation can be achieved using a blow molding co-extrusion method with an annular die or a T-die co-extrusion method. Specifically, the blow molding co-extrusion method allows for melt co-extrusion at temperatures as low as 200°C, thus suppressing the thermal decomposition and volatilization (vaporization) of the vaporizable rust inhibitor during film formation. Particularly when using recycled polyethylene as the second layer, the melt temperature during film formation needs to be slightly higher than that of virgin polyethylene (around 200-210°C). However, the blow molding co-extrusion method allows the melt temperature of the first layer's polyethylene to be set below 200°C, and air cooling during film formation further reduces the thermal impact on the first layer. As a result, a rust-preventive film with excellent rust-preventive properties can be obtained while using recycled resin. Furthermore, by producing a three-layer co-extruded film of polyethylene as described in the third aspect of this disclosure, puncture resistance is improved compared to a single-layer film. Therefore, even in cases where the packaging contains protruding metal mechanical components, the anti-rust film according to the present invention can suppress breakage caused by mechanical parts.

[0164] In forming the first layer, to improve the dispersibility of the vaporizable rust inhibitor, a masterbatch containing the vaporizable rust inhibitor can be used, and a material obtained by blending the masterbatch with polyethylene of a given density can be co-extruded into a film. There are no particular restrictions on the proportion of the vaporizable rust inhibitor in the masterbatch, as long as the masterbatch is blended with polyethylene of a given density in a manner that ensures the proportion of the vaporizable rust inhibitor in the first layer is within the aforementioned range.

[0165] It should be noted that the rust-preventive film of the third method of this disclosure can have various additives added to any one or more layers without impairing its properties. Examples of additives include antioxidants, slip agents, plasticizers, UV stabilizers, anti-staining agents, matting agents, deodorizers, flame retardants, weathering agents, antistatic agents, wire friction reducers, release agents, ion exchangers, anti-blocking agents, and coloring pigments.

[0166] The rust-proof film of the third aspect of this disclosure can be used as packaging material for metal components such as packaging machinery parts. There are no particular limitations on the shape or form of the packaging material; it can be made into a film-like form to wrap the contents, or it can be folded or overlapped and then heat-sealed to form a bag-like form.

[0167] It should be noted that the anti-rust film of embodiments 1 to 3 of this disclosure can have various additives added to any one or more layers without impairing its properties. Examples of additives include slip agents, plasticizers, UV stabilizers, anti-staining agents, matting agents, deodorizers, flame retardants, weathering agents, antistatic agents, wire friction reducers, release agents, ion exchangers, anti-blocking agents, and coloring pigments.

[0168] The rust-proof films of embodiments 1 to 3 of this disclosure can be used as packaging materials for metal components such as packaging machinery parts. There are no particular limitations on the shape or form of the packaging material; it can be made into a film-like form to wrap the contents, or it can be folded or overlapped and then heat-sealed to form a bag-like form.

[0169] Example

[0170] Hereinafter, the anti-rust films of the first to third embodiments of the present disclosure will be described in more detail using examples; however, the anti-rust films of the first to third embodiments of the present disclosure are not limited to the following examples.

[0171] [Example 1]

[0172] A co-extruded film consisting of three layers (layer 1, layer 2, and layer 3) is produced using a co-extrusion blow molding machine.

[0173] As the first layer, recycled polyethylene (density 0.920 g / cm³) is used. 3The material is prepared by dry blending the recycled polyethylene with the masterbatch of the vaporizing rust inhibitor at a ratio of 90:10 by weight, using an MFR of 1.0 g / 10 min (MFR 1.0 g / 10 min, manufactured by Dow Chemical Company, XUS60922.01), a phenolic antioxidant (manufactured by BASF JAPAN, Irganox 1010) at a ratio of 1500 ppm relative to the recycled polyethylene, and the vaporizing rust inhibitor masterbatch. The masterbatch of the vaporizing rust inhibitor is prepared by mixing the ester compounds of valeric acid, hexanoic acid, heptanoic acid, and octanoic acid into the aforementioned polyethylene at a ratio of 10% by weight.

[0174] As the second layer, recycled polyethylene (density 0.920 g / cm³) is used. 3 MFR 1.0 g / 10 min, manufactured by Dow Chemical Company, XUS60922.01), and an amount of phenolic antioxidant (manufactured by BASF JAPAN, Irganox 1010) in proportion to 1500 ppm of recycled polyethylene.

[0175] As the third layer, linear low-density polyethylene (density 0.931 g / cm³) is used. 3 MFR 2.1g / 10 minutes, manufactured by Prime Polymer Co., Ltd., UZ3520.

[0176] The thickness of each layer of the rust-preventive film obtained as described above is 20 μm for the first layer, 50 μm for the second layer, and 10 μm for the third layer.

[0177] [Example 2]

[0178] Except that the carboxylic acid ester compound was replaced by benzotriazole, a heterocyclic aromatic compound, as a vaporizing rust inhibitor, a rust-preventive film was obtained in the same manner as in Example 1.

[0179] [Comparative Example 1]

[0180] Except that ethanolamine, an amine-based flammable rust inhibitor, was used instead of carboxylic acid ester compounds as a masterbatch containing a flammable rust inhibitor, a rust-preventive film was obtained in the same manner as in Example 1.

[0181] [Comparative Example 2]

[0182] Except that a phosphoric acid antioxidant (BASF JAPAN, Irgafos 168) was used as an antioxidant to replace the phenolic antioxidant, a rust-preventive film was obtained in the same manner as in Example 1.

[0183] [Rust prevention evaluation]

[0184] Each rust-preventive film obtained as described above was cut into 150mm×200mm pieces. The resulting samples were used as evaluation samples and covered on a degreased iron plate (gray cast iron, FC200, degreased, shape: 40mm×60mm×10mm). After being stored in a constant temperature bath adjusted to 40℃ and 90%RH for 20 days, the appearance of the iron plate was evaluated according to the following evaluation criteria.

[0185] ◎: No rust or discoloration, or only spot rust and slight discoloration.

[0186] 〇: Rust occurs in less than 10% of the area relative to the surface of the iron plate.

[0187] △: Rusting occurs on areas covering more than 10% but less than 50% of the iron plate surface.

[0188] ×: Rust occurs on more than 50% of the surface area of ​​the iron plate.

[0189] The evaluation results are shown in Table 1 below.

[0190] In addition, the resin compositions (recycled polyethylene, antioxidant, and vaporizable rust inhibitor) constituting the first layer of Example 1 and Comparative Example 1 were measured using a mass spectrometry analysis apparatus (GCMS-QP2010, manufactured by Shimadzu Corporation), and the reduction in the amount of vaporizable rust inhibitor was evaluated. It should be noted that only the vaporizable rust inhibitor was measured and set as a blank. The measurement results are presented as follows: Figure 4 middle.

[0191] In addition, the reduction in the amount of vaporizable rust inhibitor was evaluated for each resin composition constituting the first layer in Examples 1 and 2 in the same manner as described above. The measurement results are presented as follows: Figure 5 middle.

[0192] [Table 1]

[0193]

[0194] From the evaluation results in Table 1 and Figures 4-5 It is clear that the rust-preventive film disclosed herein still exhibits excellent rust-preventive properties while using recycled resin.

[0195] [Example 3]

[0196] A co-extruded film consisting of three layers (layer 1, layer 2, and layer 3) is produced using a co-extrusion blow molding machine.

[0197] As a component of the first layer, linear low-density polyethylene (density 0.916 g / cm³) is used. 3This material is obtained by dry blending a masterbatch of a vaporizable rust inhibitor (MFR2.3g / 10min, Japanese polyethylene, NF444N) with a 90:10 ratio by weight. The masterbatch of the vaporizable rust inhibitor is obtained by mixing ester compounds of valeric acid, hexanoic acid, heptanoic acid, and octanoic acid into the above-mentioned linear low-density polyethylene at a ratio of 10% by weight.

[0198] As a component of the second layer, recycled polyethylene (density 0.920 g / cm³) is used. 3 MFR 1.0 g / 10 min, manufactured by Dow Chemical Company, XUS60922.01), and an amount of phenolic antioxidant (manufactured by BASF JAPAN, Irganox 1010) in proportion to 1500 ppm of recycled polyethylene.

[0199] As a component of the third layer, linear low-density polyethylene (density 0.931 g / cm³) is used. 3 MFR 2.1g / 10 minutes, manufactured by Prime Polymer Co., Ltd., UZ3520.

[0200] The thickness of each layer of the rust-preventive film obtained as described above is 20 μm for the first layer, 50 μm for the second layer, and 10 μm for the third layer.

[0201] [Example 4]

[0202] Except that ethanolamine, an amine-based flammable rust inhibitor, was used instead of carboxylic acid ester compounds as a masterbatch containing a flammable rust inhibitor, a rust-preventive film was obtained in the same manner as in Example 3.

[0203] [Example 5]

[0204] Except that a phenolic antioxidant (BASF JAPAN, Irgafos 168) was used instead of a carboxylic acid ester compound as a vaporizing rust inhibitor, a rust-preventive film was obtained in the same manner as in Example 3.

[0205] [Example 6]

[0206] In addition to using recycled polyethylene (density 0.920 g / cm³) as the third layer 3 Except for MFR1.0g / 10min, manufactured by Dow Chemical Company, XUS60922.01), a rust-preventive film was obtained in the same manner as in Example 3.

[0207] [Comparative Example 3]

[0208] As the first layer, recycled polyethylene (density 0.920 g / cm³) is used. 3The material was prepared by dry blending the recycled polyethylene with the masterbatch of the vaporizing rust inhibitor at a ratio of 96:4 by weight, using an MFR of 1.0 g / 10 min (MFR 1.0 g / 10 min, manufactured by Dow Chemical Company, XUS60922.01), a phenolic antioxidant (manufactured by BASF JAPAN, Irgafos 168) at a ratio of 1500 ppm relative to the recycled polyethylene, and a masterbatch of the vaporizing rust inhibitor. The masterbatch of the vaporizing rust inhibitor was prepared by mixing the ester compounds of valeric acid, hexanoic acid, heptanoic acid, and octanoic acid into the material obtained by the recycled polyethylene at a ratio of 10% by weight. Otherwise, a rust-preventive film was obtained in the same manner as in Example 3.

[0209] [Comparative Example 4]

[0210] Except that ethanolamine, an amine-based flammable rust inhibitor, was used instead of carboxylic acid ester compounds as a masterbatch containing flammable rust inhibitors, a rust-preventive film was obtained in the same manner as in Comparative Example 3.

[0211] [Rust prevention evaluation]

[0212] Each rust-preventive film obtained as described above was cut into 150mm×200mm pieces. The resulting samples were used as evaluation samples and covered on a degreased iron plate (gray cast iron, FC200, degreased, shape: 40mm×60mm×10mm). After being stored in a constant temperature bath adjusted to 40℃ and 90%RH for 20 days, the appearance of the iron plate was evaluated according to the following evaluation criteria.

[0213] ◎: No rust or discoloration, or only spot rust and slight discoloration.

[0214] 〇: Rust occurs in less than 10% of the area relative to the surface of the iron plate.

[0215] △: Rusting occurs on areas covering more than 10% but less than 50% of the iron plate surface.

[0216] ×: Rust occurs on more than 50% of the surface area of ​​the iron plate.

[0217] The evaluation results are shown in Table 2 below.

[0218] In addition, the resin compositions (recycled polyethylene, antioxidant, and vaporizable rust inhibitor) constituting the first layer of Examples 3 and Comparative Example 3 were measured using a mass spectrometry analysis apparatus (GCMS-QP2010, manufactured by Shimadzu Corporation), and the reduction in the amount of vaporizable rust inhibitor was evaluated. It should be noted that only the vaporizable rust inhibitor was measured and set as a blank. The measurement results are presented as follows: Figure 6 middle.

[0219] Furthermore, the reduction in the amount of vaporizable rust inhibitor was evaluated in the same manner as described above for each resin composition constituting the first layer in Example 4 and Comparative Example 4. The measurement results are presented as follows: Figure 7 middle.

[0220] [Table 2]

[0221]

[0222] From the evaluation results in Table 2 and Figures 6-7 It is clear that the anti-rust film of the present invention still has excellent anti-rust properties while using recycled resin.

[0223] [Example 7]

[0224] A co-extruded film consisting of three layers (layer 1, layer 2, and layer 3) is produced using a co-extrusion blow molding machine.

[0225] As a component of the first layer, linear low-density polyethylene (density 0.916 g / cm³) is used. 3 This material is obtained by dry blending a masterbatch of volatile rust inhibitor (MFR2.3g / 10min, manufactured by Prime Polymer Co., Ltd., SP2020) and a vaporizable rust inhibitor at a ratio of 96:4 by weight. The masterbatch of the vaporizable rust inhibitor is obtained by mixing ester compounds of valeric acid, hexanoic acid, heptanoic acid, and octanoic acid into the above-mentioned linear low-density polyethylene at a ratio of 10% by weight.

[0226] As a component of the second layer, recycled polyethylene (density 0.920 g / cm³) is used. 3 MFR 1.0g / 10 minutes, manufactured by Dow Chemical Company, XUS60922.01).

[0227] As a component of the third layer, linear low-density polyethylene (density 0.931 g / cm³) is used. 3 MFR 2.1g / 10 minutes, manufactured by Prime Polymer Co., Ltd., UZ3520.

[0228] The thickness of each layer of the rust-preventive film obtained as described above is 20 μm for the first layer, 50 μm for the second layer, and 10 μm for the third layer.

[0229] [Example 8]

[0230] As a component of the second layer, recycled polyethylene (density 0.920 g / cm³) is used. 3 MFR 1.0 g / 10 min, manufactured by Dow Chemical Company, XUS60922.01) and linear low-density polyethylene (density 0.921 g / cm³). 3The material (MFR 2.0 g / 10 min, manufactured by Nippon Polyethylene Co., Ltd.) was dry-blended at a ratio of 1:1 by weight. Otherwise, a co-extruded film was prepared in the same manner as in Example 7 to obtain a rust-preventive film. The thickness of each layer of the resulting rust-preventive film was 20 μm for the first layer, 50 μm for the second layer, and 10 μm for the third layer.

[0231] [Example 9]

[0232] As a component of the first layer, recycled polyethylene (density 0.920 g / cm³) is used. 3 MFR 1.0g / 10min, manufactured by Dow Chemical Company, XUS60922.01), linear low-density polyethylene (density 0.919g / cm³). 3 The material was obtained by dry blending the masterbatch of the above-mentioned vaporizable rust inhibitor (MFR 2.0 g / 10 min, manufactured by Prime Polymer Co., Ltd., UZ2021L) in a mass ratio of 66:28:6. Otherwise, a co-extruded film was prepared in the same manner as in Example 8 to obtain a rust-preventive film. The thickness of each layer of the obtained rust-preventive film was 20 μm for the first layer, 50 μm for the second layer, and 10 μm for the third layer.

[0233] [Example 10]

[0234] As a component of the first layer, recycled polyethylene (density 0.920 g / cm³) is used. 3 Except for the material obtained by dry blending the masterbatch of the above-mentioned vaporizable rust inhibitor (MFR 1.0 g / 10 min, manufactured by Dow Chemical Company, XUS60922.01) at a mass ratio of 96:4, a co-extruded film was prepared in the same manner as in Example 9 to obtain a rust-preventive film. The thickness of each layer of the obtained rust-preventive film was 20 μm for the first layer, 60 μm for the second layer, and 10 μm for the third layer.

[0235] [Comparative Example 5]

[0236] Bags made of a film mixed with a vaporizable rust inhibitor (thickness 80μm, width 200mm × height 300mm, manufactured by GSI Creos Co., Ltd., BCK082030).

[0237] [Rust prevention evaluation]

[0238] Each rust-preventive film obtained as described above was cut into 150mm × 200mm pieces. These samples were used as evaluation samples and covered a degreased iron plate (gray cast iron, FC200, degreased, shape: 40mm × 60mm × 10mm). After being stored in a constant temperature bath adjusted to 40°C and 90% RH for 20 days, the appearance of the iron plate was evaluated according to the following evaluation criteria. It should be noted that, regarding Comparative Example 5, one side of the bag was cut into 150mm × 200mm pieces, and the resulting sample was used as the evaluation sample.

[0239] ◎: No rust or discoloration, or only spot rust and slight discoloration.

[0240] 〇: Rust occurs in less than 10% of the area relative to the surface of the iron plate.

[0241] △: Rusting occurs on areas covering more than 10% but less than 50% of the iron plate surface.

[0242] ×: Rust occurs on more than 50% of the surface area of ​​the iron plate.

[0243] The evaluation results are shown in Table 3 below.

[0244] Additionally, a photograph showing the appearance of the iron plate surface after 20 days of storage in a constant temperature bath is provided. Figure 3 middle.

[0245] [Puncture Resistance Evaluation]

[0246] Fix each anti-rust film with a clamp. According to JIS Z1707, puncture the third layer of the anti-rust film with a semi-circular needle with a diameter of 1.0 mm and a tip radius of 0.5 mm at a test speed of 50 mm / min. Measure the maximum force (N) until the needle penetrates the film.

[0247] The measurement results are shown in Table 3 below.

[0248] [Mechanical property evaluation]

[0249] Each anti-rust film was cut into 50mm × 50mm pieces, and the resulting samples were used as evaluation samples. Tensile tests were conducted according to JIS Z1702, applying a tensile load at a test speed of 300mm / min until the evaluation sample fractured. The maximum load and the mark interval at fracture were determined. The maximum load and the mark interval at fracture were determined in both the MD and TD directions of the evaluation sample. It should be noted that the thickness of the evaluation sample was measured at a total of three locations, including the mark interval, and the average value was taken as the thickness.

[0250] The measurement results are shown in Table 3 below.

[0251] [Table 3]

[0252]

[0253] From the evaluation results in Table 3 and Figure 8 It is clear that the rust-preventive film of the present invention, while using recycled resin, still has the same or better rust-preventive performance as conventional single-layer rust-preventive films that do not use recycled resin.

[0254] Explanation of reference numerals in the attached figures

[0255] 1. Anti-rust film, 10 for the first layer, 20 for the second layer, 30 for the third layer.

Claims

1. A rust-preventive film comprising at least recycled polyethylene, a vaporizable rust inhibitor, and an antioxidant. The vaporizable rust inhibitor is selected from carboxylic acid esters and heterocyclic aromatic compounds. The antioxidant is a phenolic antioxidant.

2. The anti-rust film according to claim 1, wherein, The vaporizable rust inhibitor is contained in a proportion of 2% to 10% by mass relative to recycled polyethylene.

3. The anti-rust film according to claim 1, wherein, The antioxidant is contained in the recycled polyethylene at a ratio of 500 ppm to 5000 ppm.

4. The anti-rust film according to claim 1, comprising a first layer containing at least recycled polyethylene, a vaporizable rust inhibitor, and an antioxidant, and a second layer containing polyethylene. The polyethylene constituting the second layer is at least one type selected from recycled polyethylene and virgin polyethylene. The first layer and the second layer are formed by co-extrusion film formation.

5. The anti-rust film according to claim 4, wherein, The recycled polyethylene has a density of 0.860 g / cm³. 3 Above and 0.932 g / cm 3 The following polyethylene.

6. A rust-preventive film comprising at least a first layer containing virgin polyethylene and a vaporizable rust inhibitor, and a second layer containing recycled polyethylene and an antioxidant. The first layer and the second layer are formed by co-extrusion film formation.

7. The anti-rust film according to claim 6, wherein, The antioxidant is a phenolic antioxidant.

8. The anti-rust film according to claim 6, wherein, The vaporizable rust inhibitor is selected from at least one of carboxylic acid ester rust inhibitors, alkanolamine rust inhibitors, and heterocyclic aromatic compounds.

9. The anti-rust film according to claim 6, wherein, The second layer further comprises virgin polyethylene.

10. The anti-rust film according to claim 6, wherein, The vaporizable rust inhibitor is contained in a proportion of 2% to 10% by mass relative to the virgin polyethylene of the first layer.

11. The anti-rust film according to claim 6, wherein, The antioxidant is contained in a proportion of 500 ppm to 5000 ppm relative to the polyethylene constituting the second layer.

12. The anti-rust film according to claim 6, wherein, The polyethylene constituting the first layer has a density of 0.860 g / cm³. 3 Above and 0.932 g / cm 3 The following polyethylene.

13. The rust-preventive film according to claim 6, further comprising a third layer formed of polyethylene. The first layer, the second layer, and the third layer are formed by co-extrusion film formation.

14. A rust-preventive film comprising a first layer, a second layer, and a third layer, The first layer contains a vaporizable rust inhibitor and a density of 0.860 g / cm³. 3 Above and 0.932 g / cm 3 The following polyethylene, The second layer contains recycled polyethylene. The third layer comprises polyethylene with the same or higher density than the polyethylene constituting the first layer. The first layer, the second layer, and the third layer are formed by co-extrusion film formation.

15. The anti-rust film according to any one of claims 5, 12, and 14, wherein, The first layer has a density of 0.860 g / cm³. 3 Above and 0.932 g / cm 3 The polyethylene described below is selected from at least one of low-density polyethylene and linear low-density polyethylene.

16. The anti-rust film according to claim 14, wherein, The vaporizing rust inhibitor is selected from at least one of carboxylic acid ester-based rust inhibitors and alkanolamine-based rust inhibitors.

17. The anti-rust film according to claim 14, wherein, The first layer contains 2% to 10% by mass of the vaporizable rust inhibitor.

18. The anti-rust film according to claim 14, wherein, The second layer has a thickness that is 2 to 4 times greater than that of the first layer.

19. The anti-rust film according to claim 14, wherein, The second layer comprises recycled polyethylene and virgin polyethylene.

20. The anti-rust film according to claim 14, wherein, The first layer has a density of 0.860 g / cm³. 3 Above and 0.932 g / cm 3 The following polyethylene is selected from at least one of virgin polyethylene and recycled polyethylene.

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