Rust-preventing film

Abstract

This rust-preventing film contains at least recycled polyethylene, a vaporizable rust inhibitor, and an antioxidant. The vaporizable rust inhibitor is selected from a carboxylic acid ester and a heterocyclic aromatic compound. The antioxidant is a phenolic antioxidant.

Description

Anti-rust film

[0001] The present disclosure relates to an anti-rust film, and more particularly to an anti-rust film for packaging metal components such as machine parts to prevent the metal surface from oxidizing and causing rust during storage, transportation, or transport.

[0002] Conventionally, when metal components are stored for a long period of time, they are generally stored after being coated with anti-rust oil to prevent rust. However, for machine parts that cannot be protected from rust by coating with anti-rust oil, a method of storing them by packaging them with a volatile anti-rust agent or an anti-rust film made by kneading a volatile anti-rust agent into a resin film is known.

[0003] The anti-rust film using the above-mentioned volatile anti-rust agent must be breathable so that the volatile anti-rust agent can evaporate. Since a single-layer film causes the volatile anti-rust agent to volatilize not only inside but also outside the package, a multilayer film configuration has been adopted. For example, a multilayer film has been proposed in which a resin film containing a volatile anti-rust agent is laminated with a base film such as nylon. It is believed that such a multilayer anti-rust film can suppress the diffusion or volatilization of the volatile anti-rust agent to the outer layer (atmosphere side) and maintain a high rust-inhibiting effect for a long period of time (for example, Patent Document 1).

[0004] Also proposed is a multilayer film that contains a volatile rust inhibitor in the innermost layer, has a layer made of a gas barrier resin as an intermediate layer, and has a substrate layer as the outermost layer. It is known that the provision of the intermediate layer in this multilayer film improves the barrier properties against vaporized gas of the rust inhibitor, oxygen, or water vapor (see, for example, Patent Document 2).

[0005] Furthermore, a multilayer anticorrosive film has been disclosed in which a barrier film having a vapor-deposited film and an organic coating layer provided on a substrate to improve barrier properties is laminated onto a sealant layer (for example, Patent Document 3).

[0006] JP 2013-059864 A JP 2019-155611 A JP 2020-189689 A

[0007] In recent years, the use of recycled products has been recommended from the viewpoint of reducing environmental impact. Active efforts are being made to use recycled resin products in the field of packaging films, etc. However, while recycled resins such as polyester and polyethylene are commercially available, recycled products of special gas barrier resins, etc., are not currently available on the market.

[0008] Furthermore, for example, recycled polyethylene may contain an antioxidant to prevent thermal decomposition or gelation during remelting during recycling. Phenol-based antioxidants and phosphoric acid-based antioxidants are used as antioxidants to prevent thermal degradation of polyethylene.

[0009] In the anticorrosive film containing the above-mentioned volatile anticorrosive agent, if an antioxidant is contained in the recycled polyethylene constituting the resin film, the antioxidant may inactivate the volatile anticorrosive agent, thereby reducing the anticorrosive effect of the anticorrosive film.

[0010] Furthermore, it is known that recycled polyethylene, for example, contains impurities and various grades compared to virgin polyethylene resin, and therefore requires a higher temperature during film formation. Therefore, when recycled resin is used in anti-corrosion films, there is a problem that the thermal decomposition and volatilization of the vaporizable anti-corrosion agent is accelerated.

[0011] Therefore, an object of the present disclosure is to provide an anti-rust film that uses recycled resin and yet has excellent anti-rust effects.

[0012] The present inventors have found that even when a recycled polyethylene resin contains an antioxidant, if the antioxidant is a specific compound and the volatile corrosion inhibitor used is a specific compound, it is possible to suppress the deactivation of the volatile corrosion inhibitor by the antioxidant as described above, and to achieve a rust-preventing film that has excellent rust prevention effects even when using recycled resin. A first aspect of the present disclosure is based on this finding.

[0013] The present inventors have also discovered that by incorporating a volatile corrosion inhibitor into a layer made of virgin polyethylene containing no antioxidant, and providing this layer as a separate layer from a layer made of recycled polyethylene containing an antioxidant, it is possible to suppress deactivation of the volatile corrosion inhibitor by the antioxidant, and to realize a rust-preventing film that has excellent rust prevention effects even while using recycled resin. A second aspect of the present disclosure is based on this discovery.

[0014] [1] A rust-preventive film comprising at least a recycled polyethylene, a volatile corrosion inhibitor, and an antioxidant, wherein the volatile corrosion inhibitor is selected from a carboxylic acid ester and a heterocyclic aromatic compound, and the antioxidant is a phenolic antioxidant. [2] The rust-preventive film according to [1], wherein the volatile corrosion inhibitor is contained in an amount of 2 to 10 mass% relative to the recycled polyethylene. [3] The rust-preventive film according to [1] or [2], wherein the antioxidant is contained in an amount of 500 to 5,000 ppm relative to the recycled polyethylene. [4] The rust-preventive film according to any one of [1] to [3], comprising: a first layer comprising at least a recycled polyethylene, a volatile corrosion inhibitor, and an antioxidant; and a second layer comprising polyethylene, wherein the polyethylene constituting the second layer is at least one selected from the group consisting of recycled polyethylene and virgin polyethylene, and wherein the first layer and the second layer are formed by co-extrusion. [5] The recycled polyethylene has a density of 0.860 g / cm 3 0.932g / cm or more 3The rust-preventive film according to [4], wherein the polyethylene is any one of the following: [6] A rust-preventive film comprising at least a first layer containing virgin polyethylene and a volatile corrosion inhibitor, and a second layer containing recycled polyethylene and an antioxidant, the first layer and the second layer being formed by co-extrusion. [7] The rust-preventive film according to [6], wherein the antioxidant is a phenol-based antioxidant. [8] The rust-preventive film according to [6] or [7], wherein the volatile corrosion inhibitor is at least one selected from the group consisting of a carboxylic acid ester-based corrosion inhibitor, an alkanolamine-based corrosion inhibitor, and a heterocyclic aromatic compound. [9] The rust-preventive film according to any one of [6] to [8], wherein the second layer further contains virgin polyethylene.

[10] The rust-preventive film according to any one of [6] to [9], wherein the volatile corrosion inhibitor is contained in an amount of 2 to 10% by mass relative to the virgin polyethylene in the first layer.

[11] The anticorrosive film according to any one of [6] to

[10] , wherein the antioxidant is contained in an amount of 500 to 5,000 ppm relative to the polyethylene constituting the second layer.

[12] The polyethylene constituting the first layer has a density of 0.860 g / cm 3 0.932g / cm or more 3 The anticorrosive film according to any one of [6] to

[11] , which is the following polyethylene:

[13] The anticorrosive film according to any one of [6] to

[12] , further comprising a third layer made of polyethylene, wherein the first layer, the second layer, and the third layer are formed by co-extrusion.

[14] An anticorrosive film comprising a first layer, a second layer, and a third layer, wherein the first layer contains a volatile corrosion inhibitor and a polyethylene having a density of 0.860 g / cm 3 0.932g / cm or more 3

[15] A rust-preventive film comprising the polyethylene having a density of 0.860 g / cm3 or higher, wherein the second layer comprises recycled polyethylene, and the third layer comprises polyethylene having a density equal to or higher than that of the polyethylene constituting the first layer, and wherein the first layer, the second layer, and the third layer are formed by co-extrusion. 3 0.932g / cm or more 3The anticorrosive film according to any one of [5],

[12] , and

[14] , wherein the polyethylene is at least one selected from low-density polyethylene and linear low-density polyethylene.

[16] The anticorrosive film according to

[14] , wherein the volatile corrosion inhibitor is at least one selected from carboxylic acid ester-based corrosion inhibitors and alkanolamine-based corrosion inhibitors.

[17] The anticorrosive film according to

[14] or

[16] , wherein the first layer contains 2 to 10 mass% of the volatile corrosion inhibitor.

[18] The anticorrosive film according to any one of

[14] ,

[16] , and

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

[19] The anticorrosive film according to any one of

[14] and

[16] to

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

[20] The anticorrosive film according to any one of

[14] and

[16] to

[18] , wherein the polyethylene constituting the first layer has a density of 0.860 g / cm 3 0.932g / cm or more 3 The rust-preventive film according to any one of

[14] and

[16] to

[19] , wherein the polyethylene is at least one selected from the group consisting of virgin polyethylene and recycled polyethylene.

[0015] According to the present disclosure, it is possible to provide an anti-rust film that uses recycled resin and yet has excellent anti-rust effects.

[0016] FIG. 1 is a cross-sectional schematic diagram showing an embodiment of a rust-preventive film according to the present disclosure. FIG. 2 is a cross-sectional schematic diagram showing an embodiment of a rust-preventive film according to the present disclosure. FIG. 3 is a cross-sectional schematic diagram showing an embodiment of a rust-preventive film according to the present disclosure. FIG. 4 shows the results of GC-MS measurement of the resin compositions of Example 1 and Comparative Example 1. FIG. 5 shows the results of GC-MS measurement of the resin compositions of Example 1 and Comparative Example 2. FIG. 6 shows the results of GC-MS measurement of the resin compositions of Example 3 and Comparative Example 3. FIG. 7 shows the results of GC-MS measurement of the resin compositions of Example 4 and Comparative Example 4. FIG. 8 shows photographs of the appearance of the surface of an iron plate when the rust-preventive properties of the rust-preventive films of Examples 7 to 10 and Comparative Example 5 were evaluated.

[0017] In this specification, when multiple upper limit value candidates and multiple lower limit value candidates are listed for a certain parameter, the numerical range of the parameter may be constructed by combining any one upper limit value candidate with any one lower limit value candidate. As an example, the following description will be explained: "Parameter B is preferably A1 or more, more preferably A2 or more, and even more preferably A3 or more. Parameter B is preferably A4 or less, more preferably A5 or less, and even more preferably A6 or less." In this example, the numerical range of parameter B may be A1 or more and A4 or less, A1 or more and A5 or less, A1 or more and A6 or less, A2 or more and A4 or less, A2 or more and A5 or less, A2 or more and A6 or less, A3 or more and A4 or less, A3 or more and A5 or less, or A3 or more and A6 or less.

[0018] As used herein, polyethylene refers to a polymer in which the content of ethylene-derived structural units exceeds 50 mol% of the total amount of structural units derived from polymerizable monomers. In this polymer, the content of ethylene-derived structural units is preferably 70 mol% or more, more preferably 80 mol% or more, even more preferably 90 mol% or more, and particularly preferably 95 mol% or more. The content is measured by nuclear magnetic resonance spectroscopy (NMR).

[0019] In this specification, polyethylene may be a homopolymer of ethylene or a copolymer of ethylene and an ethylenically unsaturated monomer other than ethylene. Examples of the ethylenically unsaturated monomer other than ethylene include α-olefins having 3 to 20 carbon atoms, 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)acrylic acid esters, such as methyl (meth)acrylate and ethyl (meth)acrylate.

[0020] In this specification, examples of polyethylene include high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, ethylene-vinyl acetate copolymer, and ethylene-(meth)acrylic acid ester copolymer.

[0021] In this specification, the density of polyethylene is as follows: The density of low-density polyethylene is 0.860 g / cm 3 0.932g / cm or more 3 or less, more preferably 0.900 g / cm 3 0.932g / cm or more 3 The density of linear low density polyethylene is 0.860 g / cm 3 0.932g / cm or more 3 or less, more preferably 0.900 g / cm 3 0.932g / cm or more 3 The density of medium density polyethylene is 0.932 g / cm 3 exceeding 0.945 g / cm 3 The density of high density polyethylene is 0.945 g / cm 3 more than 0.965 g / cm 3 The density of polyethylene is measured in accordance with JIS K7112-2:2023 (density gradient tube method, 23°C).

[0022] Low-density polyethylene is, for example, polyethylene obtained by polymerizing ethylene by high-pressure polymerization (high-pressure low-density polyethylene). Linear low-density polyethylene is, for example, polyethylene obtained by polymerizing ethylene and a small amount of α-olefin by a polymerization method using a multi-site catalyst such as a Ziegler-Natta catalyst or a single-site catalyst such as a metallocene catalyst.

[0023] Polyethylenes with different densities or branches can be obtained by appropriately selecting a polymerization method. For example, it is preferable to carry out polymerization in one stage or two or more stages by any of gas phase polymerization, slurry polymerization, solution polymerization, and high pressure ionic polymerization using a multi-site catalyst such as a Ziegler-Natta catalyst or a single-site catalyst such as a metallocene catalyst as a polymerization catalyst.

[0024] The melt flow rate (MFR) of polyolefins such as polyethylene in this specification is described below. From the viewpoint of film-forming ability and processability, the MFR is preferably 0.1 g / 10 min or more, more preferably 0.3 g / 10 min or more, even more preferably 0.5 g / 10 min or more, and preferably 30 g / 10 min or less, more preferably 20 g / 10 min or less, even more preferably 10 g / 10 min or less, and particularly preferably 5 g / 10 min or less. The MFR is, for example, 0.1 g / 10 min or more and 30 g / 10 min or less. The MFR of polyolefins is measured by Method A under a load of 2.16 kg in accordance with JIS K7210-1:2014. The MFR measurement temperature is set depending on the melting point of the polyolefin, and in the case of polyethylene, it is 190°C.

[0025] In this specification, a biomass-derived resin material (hereinafter also referred to as "biomass polyethylene") may be used as polyethylene. The biomass material is, for example, a resin material obtained using a biomass-derived raw material (specifically, a plant-derived raw material) as at least a part of the raw material. The biomass material is a carbon-neutral material, and therefore can reduce the environmental load.

[0026] In this specification, recycled polyethylene refers to polyethylene recycled by mechanical or chemical recycling from used polyethylene products. Mechanical recycling generally involves crushing recovered polyethylene film, washing it with an alkali to remove dirt and foreign matter from the film surface, and then drying it at high temperature and reduced pressure for a certain period of time to diffuse contaminants remaining inside the film, thereby decontaminating it and removing the dirt from the film, and returning it to polyethylene. Chemical recycling generally involves decomposing recovered polyethylene film to the monomer level and repolymerizing the monomer 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.

[0027] Hereinafter, embodiments of the present disclosure will be described in detail. The present disclosure can be implemented in many different forms, and should not be construed as being limited to the description of the embodiments exemplified below. For clarity of explanation, the drawings may show the width, thickness, shape, etc. of each layer more schematically than in the embodiments, but these are merely examples and do not limit the interpretation of the present disclosure. In this specification and each drawing, elements similar to those already described with reference to the previous drawings are designated by the same reference numerals, and detailed descriptions may be omitted as appropriate.

[0028] <First Aspect> Hereinafter, an embodiment of the anticorrosive film according to the first aspect of the present disclosure will be described with reference to the drawings as appropriate.

[0029] FIG. 1 is a cross-sectional schematic diagram showing one embodiment of a rust-preventing film according to the first aspect of the present disclosure. The rust-preventing film 1 according to one embodiment of the present disclosure is composed of a first layer 10 containing at least recycled polyethylene, a volatile corrosion inhibitor, and an antioxidant. FIGS. 2 and 3 are cross-sectional schematic diagrams showing another embodiment of a rust-preventing film according to the first aspect of the present disclosure. The rust-preventing film 1 according to another embodiment of the rust-preventing film according to the first aspect of the present disclosure may be configured to include a first layer 10 containing at least recycled polyethylene, a volatile corrosion inhibitor, and an antioxidant, and a second layer 20 containing at least one material selected from the group consisting of recycled polyethylene and virgin polyethylene. Furthermore, in addition to the second layer, the rust-preventing film may further include a third layer 30 containing at least one material selected from the group consisting of recycled polyethylene and virgin polyethylene, as shown in FIG. 3. In the rust-preventive film 1 according to the first embodiment of the present disclosure shown in Figures 2 and 3, the first layer 10 containing a volatile rust inhibitor constitutes the innermost layer when the rust-preventive film is used as a package for metal parts, etc. In the rust-preventive film 1 according to the first embodiment of the present disclosure shown in Figure 2, the second layer 20 constitutes the outermost layer when the rust-preventive film is used as a package for metal parts, etc. In the rust-preventive film 1 according to the first embodiment of the present disclosure shown in Figure 3, the third layer 30 constitutes the innermost layer when the rust-preventive film is used as a package 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. Each layer constituting the rust-preventive film 1 according to the first embodiment of the present disclosure will now be described.

[0030] When the rust-preventive film according to the first aspect of the present disclosure is composed of a single layer as shown in FIG. 1 , the layer contains at least recycled polyethylene, a volatile rust inhibitor, and an antioxidant. Recycled polyethylene, particularly mechanically recycled polyethylene, is produced by remelting used polyethylene as described above. An antioxidant may be added to prevent thermal degradation of the polyethylene during this process. The antioxidant captures radicals generated by thermal decomposition of polyethylene during remelting, thereby suppressing scission of the polyethylene molecular chain and crosslinking reactions. However, such antioxidants may deactivate volatile rust inhibitors. Among volatile rust inhibitors, carboxylic acid esters and heterocyclic aromatic compounds are particularly susceptible to significant deactivation by amine-based antioxidants. Furthermore, amine-based rust inhibitors, among volatile rust inhibitors, have a chemical structure similar to that of amine-based antioxidants. Therefore, even if an amine-based rust inhibitor is used as a volatile rust inhibitor, it functions as an antioxidant (radical scavenger) due to the influence of heat during film formation, resulting in a reduced rust-preventive effect of the resulting rust-preventive film. In a first aspect of the present disclosure, a phenolic antioxidant is used as the antioxidant, and a carboxylic acid ester-based rust inhibitor or a heterocyclic aromatic compound is used as the volatile rust inhibitor, thereby suppressing a decrease in the rust prevention effect when the anticorrosive film is formed. By using such a specific volatile rust inhibitor and a specific antioxidant in combination, it is possible to realize an anticorrosive film that has excellent rust prevention effect while reducing the environmental load.

[0031] When the anticorrosive film according to the first aspect of the present disclosure is configured as a single layer as shown in Figure 1, the layer contains recycled polyethylene as a main resin component. In the present disclosure, "a layer containing recycled polyethylene as a main component" means a layer in which the recycled polyethylene content is 50% by mass or more based on 100% by mass of the layer. The content is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more.

[0032] The density of recycled polyethylene is 0.860 g / cm 3 0.932g / cm or more3 As the polyethylene having a density in this range, low-density polyethylene and linear low-density polyethylene can be suitably used, and linear low-density polyethylene can be more preferably used. As an example, a polyethylene having a density of 0.900 g / cm 3 0.932g / cm or more 3 It is more preferable to use the following linear low density polyethylene:

[0033] In addition, even when virgin polyethylene is included in addition to recycled polyethylene as a resin component, the density of virgin polyethylene is 0.860 g / cm 3 0.932g / cm or more 3 It is preferable that the density is 0.900 g / cm or less, and more preferably, linear low-density polyethylene can be used. 3 0.932g / cm or more 3 It is more preferable to use the following linear low density polyethylene:

[0034] When the anticorrosive film according to the first aspect of the present disclosure is configured as a single layer as shown in FIG. 1 , it contains a phenolic antioxidant together with the recycled polyethylene that configures the layer. Examples of phenolic antioxidants include octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and pentaerythritol tetrakis[3-(3,5-ditert-butyl-4-hydroxyphenyl)propionate]. Commercially available phenolic antioxidants may also be used, such as 3,3',3pha',.alpha",5,5',5"-Hexa-tert-butyl-.alpha,.alpha',.alpha"-(mesitylene-2,4,6-triyl)tri-p-cresol (IRGANOX, manufactured by BASF). 1330), 3,9-Bis{2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1-dimethylethyl}-2,4,8,10-tetraoxaspiro[5.5]undecane (manufactured by ADEKA, Adekastab AO-80), and the like.

[0035] The phenolic antioxidant may be kneaded into recycled polyethylene to form a rust-preventive film, or the phenolic antioxidant may be added when used polyester is remelted by mechanical recycling, i.e., the phenolic antioxidant may be contained in the recycled polyester in advance.

[0036] The phenolic antioxidant is preferably contained in a proportion of 500 to 5,000 ppm, more preferably 1,000 to 4,000 ppm, relative to the recycled polyethylene. This does not exclude the inclusion of phenolic antioxidants used in the production of recycled polyethylene, and the recycled polyethylene may also contain conventionally used antioxidants (phosphate-based, sulfur-based, amine-based, etc.). Furthermore, when the rust-preventive film is multilayered as described below, the volatile rust inhibitor-containing layer preferably contains the phenolic antioxidant in a proportion of 500 ppm, more preferably 1,000 to 4,000 ppm, relative to the recycled polyethylene.

[0037] Furthermore, when virgin polyethylene is contained in addition to recycled polyethylene, a phenolic antioxidant may be used during the production of the virgin polyethylene, and in this case, the content of the phenolic antioxidant is the total amount of the phenolic antioxidant contained in the recycled polyethylene and virgin polyethylene, and the phenolic antioxidant added during the production of the rust-preventive film.

[0038] As the volatile rust inhibitor, among volatile rust inhibitors that volatilize at 40°C to 60°C to exhibit rust-preventing effects (for example, 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 groups, and heterocyclic compounds such as triazole rings, pyrrole rings, pyrazole rings, thiazole rings, and imidazole rings), carboxylic acid esters and heterocyclic aromatic compounds that can suppress the reduction in rust-preventing effect caused by phenolic antioxidants are used.

[0039] Fatty acid esters can be preferably used as carboxylic acid ester-based rust inhibitors. The number of carbon atoms in the fatty acid moiety of the fatty acid ester is preferably 6 to 20. If the carbon number is less than the above range, the boiling point may be too close to the film formation temperature, which may cause bubbles to form or may make it impossible to form a film. Specific fatty acid esters include alcohol esters of the above fatty acids and glycerin fatty acid esters. As the glycerin fatty acid ester, glycerin trifatty acid ester is preferred, and glycerin tricaprylic acid ester is more preferred. Among the above fatty acids, it is preferred to use one or more selected from the group consisting of heptanoic acid, octanoic acid, decanoic acid, lauric acid, stearic acid, caprylic acid, capric acid, calcium stearate, and glycerin tricaprylic acid ester.

[0040] Examples of heterocyclic aromatic compounds include compounds having a triazole ring, a pyrrole ring, a pyrazole ring, a thiazole ring, and an imidazole ring, and in particular, compounds having a triazole ring or benzoate-based compounds are preferred. More specifically, examples of rust inhibitors having a triazole ring include benzotriazole (BTA), tolyltriazole (TTA), etc. Furthermore, examples of benzoate-based compounds include monoethanolamine benzoate (MEA·BA), dicyclohexylammonium benzoate (DICHA·BA), diisopropylammonium benzoate (DIPA·BA), etc.

[0041] From the viewpoints of the dissipation of the rust inhibitor and the extrusion film-forming properties of the resin, the amount of the volatile rust inhibitor added is preferably 0.1% by mass or more and 30% by mass or less, more preferably 0.5% by mass or more and 20% by mass or less, and even more preferably 2% by mass or more and 10% by mass or less, relative to the recycled polyethylene constituting the layer containing the volatile rust inhibitor. Note that when the layer containing the volatile rust inhibitor contains recycled polyethylene and virgin polyethylene as resin components, the amount of the volatile rust inhibitor added is preferably 0.1% by mass or more and 30% by mass or less, more preferably 0.5% by mass or more and 20% by mass or less, and even more preferably 2% by mass or more and 10% by mass or less, relative to the total amount of the recycled polyethylene and virgin polyethylene.

[0042] When the anticorrosive film according to the first aspect of the present disclosure is configured as a single layer as shown in FIG. 1 , the thickness of the anticorrosive film may be appropriately determined depending on the intended use. However, from the viewpoint of the diffusibility of the volatile anticorrosive agent, the thickness is generally 50 μm or more, more preferably 60 μm or more, and even more preferably 80 μm or more, and is generally 150 μm or less, more preferably 120 μm or less, and even more preferably 100 μm or less.

[0043] Next, an embodiment in which the rust-preventive film according to the first aspect of the present disclosure has multiple layers will be described. As shown in FIGS. 2 and 3 , the rust-preventive film according to the first aspect of the present disclosure may include a second layer in addition to the layer containing a volatile rust inhibitor (first layer), or may further include a third layer in addition to the second layer. The second and / or third layer constitute the outermost layer when the rust-preventive film is used as a package for metal parts, etc. By including an outermost layer in the rust-preventive film, the volatile rust inhibitor contained in the first layer can be prevented from diffusing into the atmosphere outside the rust-preventive film. Furthermore, the rust-preventive film has improved skewer resistance compared to a single-layer film. Therefore, even when packaging metal mechanical components with protruding portions, the rust-preventive film according to the first aspect of the present disclosure can prevent the mechanical components from tearing the film.

[0044] When the anticorrosive film is multilayered, the layer (first layer) containing the volatile corrosion inhibitor may have the same configuration as the single layer described above. Furthermore, when the film is multilayered, the first layer is preferably 3 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more, from the viewpoint of the diffusibility of the volatile corrosion inhibitor. From the viewpoint of film formability and processability, the first layer 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.

[0045] When the second layer and / or the third layer is the outermost layer, the resin component is primarily polyethylene having a density equal to or higher than that of the polyethylene constituting the layer containing the volatile corrosion inhibitor (first layer). For example, when the polyethylene constituting the first layer is low-density polyethylene or linear low-density polyethylene, the outermost layer can be made of low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, or high-density polyethylene.

[0046] The second layer provided on the outer surface of the first layer may be composed of at least one selected from the group consisting of recycled polyethylene and virgin polyethylene, but is preferably composed of recycled polyethylene from the viewpoint of reducing environmental impact. Recycled polyethylene (particularly mechanically recycled polyethylene) is a mixture of various used polyethylenes (low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, and other polyethylenes) during recycling. However, in consideration of film-forming properties and processability, it is preferable to use recycled polyethylene with an MFR of 0.1 g / 10 min to 30 g / 10 min.

[0047] The second layer may contain virgin polyethylene in addition to recycled polyethylene. By adding virgin polyethylene appropriately, film-forming properties and processability can be improved. When the second layer contains recycled polyethylene and virgin polyethylene, the content of virgin polyethylene is preferably more than 0% by mass and not more than 50% by mass, and more preferably 15% by mass or more and 35% by mass or less, based on the entire second layer.

[0048] If the second layer includes virgin polyethylene, the virgin polyethylene preferably has a viscosity of 0.860 g / cm 3 0.932g / cm or more 3 Low density polyethylene of 0.900 g / cm or less, more preferably 0.900 g / cm 3 0.932g / cm or more 3 Low density polyethylene of 0.860 g / cm or less, or preferably 0.860 g / cm 3 0.932g / cm or more 3 Linear low density polyethylene of the following: 3 0.932g / cm or more 3 The following linear low density polyethylene:

[0049] From the viewpoint of reducing the environmental load, the thickness of the second layer 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 ability and processability, the thickness 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.

[0050] Furthermore, the second layer preferably has a thickness 2 to 4 times that of the layer (first layer) containing the volatile corrosion inhibitor described above. When recycled polyethylene is used, the melting temperature during film formation must be slightly higher (approximately 200 to 210°C) than when virgin polyethylene is used. However, when the first and second layers (and even the third layer) are formed, for example, by co-extrusion film formation using inflation film extrusion, the thickness of the second layer can be set to 2 to 4 times that of the first layer, allowing for sufficient heat to melt the recycled polyethylene during extrusion film formation while allowing the surface of the innermost first layer to be air-cooled, thereby suppressing thermal degradation and volatilization of the volatile corrosion inhibitor in the first layer. More preferably, the second layer has a thickness 2 to 3 times that of the first layer.

[0051] When a third layer is provided in addition to the second layer, it is preferable to use a polyethylene having a high density for the third layer from the viewpoint of suppressing the diffusion of the volatile corrosion inhibitor. However, from the viewpoints of film formability when forming the anticorrosive film and suppressing curling of the obtained film, the polyethylene should be selected so that the density difference between the polyethylene constituting the first layer and the polyethylene constituting the third layer is not large. From the viewpoints of suppressing the diffusion of the volatile corrosion inhibitor and suppressing curling, it is preferable to use a low-density polyethylene or linear low-density polyethylene having a density equal to or higher than that of the polyethylene constituting the first layer.

[0052] The polyethylene constituting the third layer may be either virgin polyethylene or recycled polyethylene. From the viewpoint of reducing the environmental load, it is preferable to use recycled polyethylene for the third layer as well. However, as described above, from the viewpoints of inhibiting the diffusion of the volatile corrosion inhibitor and inhibiting curling, it is preferable to use virgin polyethylene (low-density polyethylene or linear low-density polyethylene) having the same or higher density as the polyethylene constituting the first layer.

[0053] The thickness of the third layer is preferably 3 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more, from the viewpoint of suppressing the diffusion of the volatile corrosion inhibitor. From the viewpoint of film-forming ability and processability, the thickness 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.

[0054] When recycled polyethylene is used for the second layer and / or the third layer, a phenolic antioxidant may be added during the production of the anticorrosive film in addition to the antioxidant contained in the recycled polyethylene during production. The amount of the phenolic antioxidant added is preferably 500 to 5,000 ppm, more preferably 1,000 to 4,000 ppm, relative to the recycled polyethylene.

[0055] Even when the anticorrosive film according to the first aspect of the present disclosure is multi-layered, the total thickness may be appropriately adjusted depending on the application, and is generally 50 μm or more, more preferably 60 μm or more, and even more preferably 80 μm or more, and is generally 150 μm or less, more preferably 120 μm or less, and even more preferably 100 μm or less.

[0056] [Method for producing anticorrosive film] When the anticorrosive film according to the first aspect of the present disclosure is a single layer, it can be obtained by mixing recycled polyethylene, a volatile corrosion inhibitor, and an antioxidant, and subjecting the mixture to inflation film formation using a circular die or extrusion film formation using a T-die, or the like.

[0057] A multilayer anticorrosive film can be obtained by co-extrusion of a layer containing a volatile corrosion inhibitor (first layer) and other layers (second to third layers). Co-extrusion can be achieved by known film-forming methods such as inflation co-extrusion and co-extrusion. Among these, inflation co-extrusion allows melt co-extrusion film formation at a lower temperature, such as 200°C or lower, thereby suppressing thermal decomposition and volatilization (evaporation) of the volatile corrosion inhibitor during film formation.

[0058] When forming a film, the components may be mixed simultaneously, or a masterbatch may be prepared in advance by mixing recycled polyethylene with a volatile corrosion inhibitor or an antioxidant, and then the recycled polyethylene and the masterbatch may be mixed to form a film. In particular, to improve the dispersibility of the volatile corrosion inhibitor, a masterbatch containing the volatile corrosion inhibitor may be used, and a film may be formed by co-extrusion using a blend of the masterbatch and recycled polyethylene. The content of the volatile corrosion inhibitor in the masterbatch is not particularly limited, but it is sufficient to blend the masterbatch with polyethylene of a predetermined density so that the content of the volatile corrosion inhibitor in the layer containing the volatile corrosion inhibitor (first layer) is within the above-mentioned range.

[0059] Second Aspect Next, an embodiment of the anticorrosive film according to the second aspect of the present disclosure will be described with reference to the drawings as appropriate.

[0060] FIG. 2 is a cross-sectional schematic diagram showing an embodiment of a rust-preventing film according to the second aspect of the present disclosure. The rust-preventing film 1 according to one embodiment of the rust-preventing film according to the second aspect of the present disclosure has a multilayer structure including at least a first layer 10 containing virgin polyethylene and a volatile corrosion inhibitor, and a second layer 20 containing recycled polyethylene and an antioxidant. FIG. 3 is a cross-sectional schematic diagram showing another embodiment of a rust-preventing film according to the second aspect of the present disclosure. The rust-preventing film 1 according to another embodiment of the rust-preventing film according to the second aspect of the present disclosure has a multilayer structure including a first layer 10 containing virgin polyethylene and a volatile corrosion inhibitor, a second layer 20 containing recycled polyethylene and an antioxidant, and a third layer 30 composed of polyethylene. The first layer containing the volatile corrosion inhibitor constitutes the innermost layer when the rust-preventing film is used as a package for metal parts, etc. In the rust-preventing film 1 according to the second aspect of the present disclosure shown in FIG. 2, the second layer 20 constitutes the outermost layer when used as a package. Furthermore, in the anti-rust film 1 according to the second embodiment of the present disclosure shown in Fig. 3, the third layer 30 is a layer that constitutes the innermost layer when the anti-rust film is used as a package for metal parts or the like, and the second layer 20 is an intermediate layer that is provided between the first layer 10, which is the innermost layer, and the third layer 30, which is the outermost layer. Each layer that constitutes the anti-rust film 1 according to the second embodiment of the present disclosure will now be described.

[0061] [First Layer] The first layer constituting the anticorrosive film according to the second aspect of the present disclosure is a layer containing virgin polyethylene as a resin component as a main component. In the present disclosure, "a layer containing polyethylene as a main component" refers to a layer in which the virgin polyethylene content is 50% by mass or more based on 100% by mass of the layer. This content is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more.

[0062] From the perspective of reducing environmental impact, recycled polyethylene is preferable to virgin polyethylene. However, recycled polyethylene, particularly mechanically recycled polyethylene, is produced by remelting used polyethylene as described above. During this process, antioxidants may be added to prevent thermal degradation of the polyethylene. Antioxidants capture radicals that cause thermal decomposition of polyethylene during remelting, thereby suppressing scission of polyethylene molecular chains and crosslinking reactions. On the other hand, such antioxidants may deactivate volatile corrosion inhibitors. As a result, the rust-preventing effect of the resulting rust-preventing film is reduced. In a second aspect of the present disclosure, a layer made of recycled polyethylene containing an antioxidant is used as the second layer, and virgin polyethylene with a low antioxidant content is used as the resin component constituting the first layer containing a volatile corrosion inhibitor, thereby achieving a rust-preventing film with excellent rust-preventing effect while reducing environmental impact.

[0063] The virgin polyethylene used for the first layer has a density of 0.860 g / cm 3 0.932g / cm or more 3 As described above, low-density polyethylene and linear low-density polyethylene can be suitably used, and linear low-density polyethylene can be more suitably used. 3 0.932g / cm or more 3 It is more preferable to use the following linear low density polyethylene:

[0064] The first layer constituting the anticorrosive film according to the second aspect of the present disclosure contains a volatile corrosion inhibitor, and can be formed by kneading the volatile corrosion inhibitor into polyethylene having a predetermined density, which is the resin component described above, and then forming the first layer into a film.

[0065] The volatile rust inhibitor may be any conventionally known volatile rust inhibitor that volatilizes at 40°C to 60°C to exhibit a rust-preventing effect, and examples thereof 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 groups, and heterocyclic compounds such as triazole rings, pyrrole rings, pyrazole rings, thiazole rings, and imidazole rings. Of these, carboxylic acid esters, alkanolamines, and heterocyclic aromatic compounds are preferred from the viewpoint of environmental adaptability.

[0066] The characteristics of the carboxylic acid ester-based rust inhibitor are as described in the first embodiment.

[0067] Examples of alkanolamine-based rust inhibitors include dicyclohexylamine, monoethanolamine, diethanolamine, diisopropylamine, cyclohexylamine, nitronaphthaleneamine, ammonium benzoate (ammonium benzoate), cyclohexylammonium benzoate, cyclohexylammonium carbamate, cyclohexylammonium nitrite, cyclohexylammonium caprylate, cyclohexylammonium laurate, dicyclohexylammonium benzoate, dicyclohexylammonium carbamate, isopropylammonium nitrite, isopropylammonium caprylate, isopropylammonium laurate, and isopropylammonium. Examples of the dibenzylammonium benzoate include dibenzylammonium nitrite, dibenzylammonium caprylate, dibenzylammonium laurate, diisopropylammonium benzoate, diisopropylammonium carbamate, benzylammonium nitrite, benzylammonium caprylate, benzylammonium laurate, benzylammonium benzoate, benzylammonium carbamate, dibenzylammonium nitrite, dibenzylammonium caprylate, dibenzylammonium laurate, dibenzylammonium benzoate, and dibenzylammonium carbamate.

[0068] The characteristics of the heteroaromatic compound are as described in the first embodiment.

[0069] From the viewpoints of the dissipation of the rust inhibitor and the extrusion film-forming properties of the resin, the amount of the volatile rust inhibitor added is preferably 0.1% by mass or more and 30% by mass or less, more preferably 0.5% by mass or more and 20% by mass or less, and even more preferably 2% by mass or more and 10% by mass or less, relative to the virgin polyethylene constituting the first layer.

[0070] The thickness of the first layer constituting the anticorrosive film is as described in the first embodiment in the case of a multilayer structure.

[0071] [Second Layer] The second layer constituting the rust-preventive film according to the second aspect of the present disclosure is the outer layer of the first layer (the layer constituting the outer side when the rust-preventive film is used as a packaging material for metal parts, etc.), and contains recycled polyethylene as a primary resin component. The use of recycled polyethylene contributes to a reduction in environmental impact. Recycled polyethylene, particularly mechanically recycled polyethylene, can suppress thermal degradation by containing an antioxidant, as described above, but this can deactivate the volatile corrosion inhibitor. The rust-preventive film according to the second aspect of the present disclosure has a second layer, separate from the first layer containing the volatile corrosion inhibitor, made of recycled polyethylene, thereby achieving excellent rust prevention while reducing the environmental impact. Furthermore, recycled polyethylene contains impurities and various grades compared to virgin polyethylene resin. Therefore, using recycled polyethylene as the primary resin for the outermost layer or the first layer requires a higher film-forming temperature. It is also known that recycled polyethylene is more likely to produce fisheyes and wrinkles during film formation than virgin polyethylene. In a second aspect of the present disclosure, the anti-rust film has a two-layer structure, and recycled polyethylene is used as the second layer, thereby solving the above-mentioned problems while reducing the environmental impact.

[0072] Recycled polyethylene (particularly mechanically recycled polyethylene) is a mixture of various types of used polyethylene (low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, and other polyethylenes) during recycling. However, in consideration of 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.

[0073] The anticorrosion film according to the second aspect of the present disclosure may contain virgin polyethylene as the second layer in addition to the recycled polyethylene. The characteristics of the virgin polyethylene that can be contained in the second layer are as described in the first aspect.

[0074] The second layer containing recycled polyethylene as a main component contains an antioxidant to prevent thermal degradation of the polyethylene, etc. As the antioxidant, conventionally known antioxidants such as phenol-based, phosphoric acid-based, sulfur-based, and amine-based antioxidants can be used, but from the viewpoint of rust prevention effect, it is preferable to use a dicyclohexylamine antioxidant.

[0075] The characteristics of the phenolic antioxidant are as described in the first embodiment.

[0076] The thickness of the second layer is as described in the first embodiment.

[0077] The second layer preferably has a thickness two to four times that of the first layer containing the volatile corrosion inhibitor, for the reasons described in the first embodiment. The second layer more preferably has a thickness two to three times that of the first layer.

[0078] [Third Layer] The rust-preventive film according to the second aspect of the present disclosure may further include a third layer in addition to the second layer. When the third layer is included, the third layer constitutes the outermost layer when the rust-preventive film is used as a package for metal parts or the like. By including the third layer in the rust-preventive film, the volatile rust inhibitor contained in the first layer can be prevented from diffusing into the atmosphere outside the rust-preventive film. The third layer primarily contains, as a resin component, polyethylene having a density equal to or higher than that of the polyethylene constituting the first layer. For example, when the polyethylene constituting the first layer is low-density polyethylene or linear low-density polyethylene, the outermost layer can be made of low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, or high-density polyethylene.

[0079] From the viewpoint of inhibiting the diffusion of the volatile corrosion inhibitor, it is preferable to use polyethylene having a high density for the third layer. However, from the viewpoint of film formability when forming the anticorrosive film and inhibiting curling of the obtained film, the polyethylene should be selected so that the density difference between the recycled polyethylene constituting the first layer, which is the innermost layer, and the polyethylene constituting the third layer, which is the outermost layer, is not large. From the viewpoint of inhibiting the diffusion of the volatile corrosion inhibitor and inhibiting curling, it is preferable to use low-density polyethylene or linear low-density polyethylene having a density equal to or higher than that of the recycled polyethylene constituting the first layer.

[0080] The polyethylene constituting the third layer may be either virgin polyethylene or recycled polyethylene. From the viewpoint of reducing the environmental load, it is preferable to use recycled polyethylene for the third layer as well. However, as described above, from the viewpoints of inhibiting the diffusion of the volatile corrosion inhibitor and inhibiting curling, it is preferable to use virgin polyethylene (low-density polyethylene or linear low-density polyethylene) having the same or higher density as the recycled polyethylene constituting the first layer.

[0081] Whether the polyethylene constituting the third layer is virgin polyethylene or recycled polyethylene, it may contain the above-mentioned phenolic antioxidant. When a phenolic antioxidant is contained, the content thereof is preferably 500 to 5,000 ppm, and more preferably 1,000 to 4,000 ppm, relative to the polyethylene constituting the third layer. Note that this does not exclude the inclusion of phenolic antioxidants used in producing recycled polyethylene, and recycled polyethylene may contain conventionally used antioxidants (phosphate-based, sulfur-based, amine-based, etc.).

[0082] The thickness of the third layer constituting the anticorrosive film is as described in the first embodiment.

[0083] The total thickness of the anticorrosive film according to the second aspect of the present disclosure is as described in the first aspect when it is multi-layered.

[0084] [Method for Producing Rust-Preventive Film] The rust-preventive film according to the second aspect of the present disclosure can be obtained by co-extrusion of the first and second layers described above (or, if a third layer is further provided, the first, second, and third layers). Co-extrusion can be achieved by a blown film co-extrusion method using a circular die or a T-die. The blown film co-extrusion method, in particular, enables melt co-extrusion film formation at a lower temperature, such as 200°C or lower, thereby suppressing thermal decomposition and volatilization (vaporization) of the volatile rust inhibitor during film formation. In particular, when recycled polyethylene is used as the resin component of the second layer, the melting temperature during film formation must be slightly higher (approximately 200 to 210°C) than that of virgin polyethylene. However, the blown film co-extrusion method allows the melting temperature of the virgin polyethylene in the first layer to be 200°C or lower, and furthermore, air cooling during film formation can be used to reduce the thermal impact on the first layer. As a result, a rust-preventive film with excellent rust prevention effects can be obtained even while using recycled resin. Furthermore, by using a two-layer or three-layer co-extruded film made of polyethylene as in the second aspect of the present disclosure, skewer resistance is improved compared to a single-layer film. Therefore, even when packaging metal machine parts with protruding parts, the rust-preventive film of the present invention can be prevented from being torn by the machine parts.

[0085] In forming the first layer, in order to improve the dispersibility of the volatile corrosion inhibitor, a masterbatch containing the volatile corrosion inhibitor may be used, and the masterbatch may be blended with polyethylene of a predetermined density for co-extrusion film formation. The content of the volatile corrosion inhibitor in the masterbatch is not particularly limited, but the masterbatch and polyethylene of a predetermined density may be blended so that the content of the volatile corrosion inhibitor in the first layer falls within the above-mentioned range.

[0086] <Third Aspect> Next, an embodiment of the anticorrosive film according to the third aspect of the present disclosure will be described with reference to the drawings as appropriate.

[0087] 3 is a cross-sectional schematic diagram showing one embodiment of an anti-rust film according to the third aspect of the present disclosure. The anti-rust film 1 according to the third aspect of the present disclosure is a co-extrusion film comprising at least a first layer 10, a second layer 20, and a third layer 30 in this order. Note that the phrase "the anti-rust film comprises the layers in this order" means that the anti-rust film 1 comprises the layers (first layer 10, second layer 20, and third layer 30) in this order in the thickness direction of the anti-rust film 1.

[0088] The first layer 10 of the anti-rust film 1 according to the third aspect of the present disclosure is a layer that constitutes the innermost layer when the anti-rust film is used as a package for metal parts or the like, the third layer 30 is a layer that constitutes the third layer when the film is used as a package, and the second layer 20 is a layer that is provided between the first layer 10 and the third layer 30. Each layer that constitutes the anti-rust film 1 according to the third aspect of the present disclosure will now be described.

[0089] [First Layer] The first layer constituting the anticorrosive film according to the third aspect of the present disclosure comprises a resin component having a density of 0.860 g / cm 3 0.932g / cm or more 3 The following refers to a layer containing polyethylene as a main component. In the present disclosure, "a layer containing polyethylene as a main component" means a layer in which the polyethylene content is 50% by mass or more based on 100% by mass of the layer. The content is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, still more preferably 90% by mass or more, and particularly preferably 95% by mass or more.

[0090] Density is 0.860 g / cm 3 0.932g / cm or more 3 As the polyethylene below, as described above, low-density polyethylene and linear low-density polyethylene can be suitably used, and linear low-density polyethylene is more preferred. 3 0.932g / cm or more 3 It is more preferable to use the following linear low density polyethylene:

[0091] Density is 0.860 g / cm3 0.932g / cm or more 3 The polyethylene below may be virgin polyethylene, or from the viewpoint of reducing the environmental load, may be recycled polyethylene, or may be a mixture of virgin polyethylene and recycled polyethylene, i.e., may be at least one selected from the group consisting of virgin polyethylene and recycled polyethylene.

[0092] The first layer constituting the rust-preventing film according to the third aspect of the present disclosure contains a volatile corrosion inhibitor, and can be formed by kneading the volatile corrosion inhibitor into polyethylene having a predetermined density, which is the resin component described above, and then forming the first layer into a film.

[0093] From the viewpoint of the dissipation of the rust inhibitor and the extrusion film-forming properties of the resin, the amount of the volatile rust inhibitor added is preferably 0.1 mass % or more and 30 mass % or less, more preferably 0.5 mass % or more and 20 mass % or less, and even more preferably 2 mass % or more and 10 mass % or less, relative to the entire first layer.

[0094] Other features of the volatile corrosion inhibitor are as described in the second embodiment.

[0095] The thickness of the first layer constituting the anticorrosive film is as described in the first embodiment in the case of a multilayer structure.

[0096] [Second Layer] The second layer constituting the rust-preventive film according to the third aspect of the present disclosure is a layer provided between the first layer and the third layer, and contains recycled polyethylene as a primary resin component. The use of recycled polyethylene contributes to a reduction in environmental impact. As described above, recycled polyethylene, particularly mechanically recycled polyethylene, contains impurities and various grades of polyethylene compared to virgin polyethylene resin. Therefore, using recycled polyethylene as the primary resin component for the third or first layer requires a higher film-forming temperature. Furthermore, recycled polyethylene is known to produce fisheyes and wrinkles during film formation compared to virgin polyethylene. In the third aspect of the present disclosure, the rust-preventive film has a three-layer structure, and recycled polyethylene is used as the second layer, thereby solving the above-mentioned problems while reducing the environmental impact.

[0097] The second layer constituting the anticorrosive film according to the third aspect of the present disclosure may or may not contain an antioxidant. Other characteristics of the second layer are as described in the second aspect.

[0098] [Third Layer] The third layer of the rust-preventive film according to the third aspect of the present disclosure constitutes the third layer when the rust-preventive film is used as a packaging material for metal parts, etc. The provision of the third layer in the rust-preventive film can prevent the volatile rust inhibitor contained in the first layer from diffusing into the atmosphere outside the rust-preventive film. The third layer contains, as a resin component, a polyethylene having a density equal to or higher than that of the polyethylene constituting the first layer. For example, when the polyethylene constituting the first layer is low-density polyethylene or linear low-density polyethylene, the third layer can be made of low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, or high-density polyethylene.

[0099] From the viewpoint of inhibiting the diffusion of the volatile corrosion inhibitor, it is preferable to use a polyethylene having a high density for the third layer. However, from the viewpoint of film formability when forming the rust-preventive film and inhibiting curling of the obtained film, the polyethylene should be selected so that the density difference between the polyethylene constituting the first layer, which is the innermost layer, and the polyethylene constituting the third layer is not large. From the viewpoint of inhibiting the diffusion of the volatile corrosion inhibitor and inhibiting curling, it is preferable to use a low-density polyethylene or linear low-density polyethylene having a density equal to or higher than that of the polyethylene constituting the first layer.

[0100] The polyethylene constituting the third layer may be either virgin polyethylene or recycled polyethylene. From the viewpoint of reducing the environmental load, it is preferable to use recycled polyethylene for the third layer as well. However, as described above, from the viewpoints of inhibiting the diffusion of the volatile corrosion inhibitor and inhibiting curling, it is preferable to use virgin polyethylene (low-density polyethylene or linear low-density polyethylene) having the same or higher density as the polyethylene constituting the first layer.

[0101] The thickness of the third layer constituting the anticorrosive film is as described in the first embodiment.

[0102] The total thickness of the anticorrosive film according to the third aspect of the present disclosure is as described in the first aspect when it is multi-layered.

[0103] [Method for Producing Rust-Preventive Film] The rust-preventive film according to the third aspect of the present disclosure can be obtained by co-extrusion of the first, second, and third layers. Co-extrusion can be achieved by blown film co-extrusion using a circular die or by co-extrusion using a T-die. In particular, blown film co-extrusion allows melt co-extrusion film formation at a lower temperature, such as 200°C or lower, thereby suppressing thermal decomposition and volatilization (vaporization) of the volatile rust inhibitor during film formation. In particular, when recycled polyethylene is used for the second layer, the melting temperature during film formation must be slightly higher (approximately 200-210°C) than that of virgin polyethylene. However, blown film co-extrusion allows the melting temperature of the polyethylene for the first layer to be 200°C or lower, and air cooling during film formation can be used to reduce the thermal impact on the first layer. As a result, a rust-preventive film with excellent rust prevention effect can be obtained even when using recycled resin. Furthermore, as in the third aspect of the present disclosure, a three-layer polyethylene co-extruded film has improved skewer resistance compared to a single-layer film, and therefore, even when packaging metal machine parts with protruding parts, the rust-preventive film of the present invention can be prevented from being torn by the machine parts.

[0104] In forming the first layer, in order to improve the dispersibility of the volatile corrosion inhibitor, a masterbatch containing the volatile corrosion inhibitor may be used, and the masterbatch may be blended with polyethylene of a predetermined density for co-extrusion film formation. The content of the volatile corrosion inhibitor in the masterbatch is not particularly limited, but the masterbatch and polyethylene of a predetermined density may be blended so that the content of the volatile corrosion inhibitor in the first layer falls within the above-mentioned range.

[0105] The anticorrosive film according to the third aspect of the present disclosure may contain various additives in one or more layers, provided that the additives do not impair the properties of the film. Examples of such additives include antioxidants, slip agents, plasticizers, UV stabilizers, color inhibitors, matting agents, deodorizers, flame retardants, weather resistance agents, antistatic agents, thread friction reducers, release agents, ion exchange agents, antiblocking agents, and color pigments.

[0106] The rust-preventive film according to the third aspect of the present disclosure can be used as a packaging material for packaging metal members such as machine parts, etc. There are no particular limitations on the shape or form of the packaging material, and the packaging material can be in the form of a film to wrap the contents, or the rust-preventive film can be folded or overlapped and heat-sealed to form a bag.

[0107] The anticorrosive films according to the first to third aspects of the present disclosure may contain various additives in one or more layers, provided that the additives do not impair the properties of the films. Examples of additives include slip agents, plasticizers, UV stabilizers, color inhibitors, matting agents, deodorizers, flame retardants, weather resistance agents, antistatic agents, thread friction reducers, release agents, ion exchange agents, antiblocking agents, and color pigments.

[0108] The rust-preventive films according to the first to third aspects of the present disclosure can be used as packaging materials for packaging metal members such as machine parts, etc. There are no particular limitations on the shape or form of the packaging material, and the contents can be wrapped in a film-like form, or the rust-preventive film can be folded or overlapped and heat-sealed to form a bag-like form.

[0109] The anti-rust films according to the first to third aspects of the present disclosure will be described in more detail below using examples, but the anti-rust films according to the first to third aspects of the present disclosure are not limited to the following examples.

[0110] [Example 1] A coextrusion inflation film-forming machine was used to produce a coextruded film having a three-layer structure of a first layer, a second layer, and a third layer. The first layer was made of recycled polyethylene (density 0.920 g / cm 3The recycled polyethylene was dry-blended in a ratio of 90:10 by mass with a phenolic antioxidant (Irganox 1010, manufactured by BASF Japan Ltd.) in an amount of 1500 ppm relative to the recycled polyethylene, and a masterbatch of the recycled polyethylene and a volatile corrosion inhibitor. The volatile corrosion inhibitor masterbatch was prepared by kneading an ester compound of pentanoic acid, hexanoic acid, heptanoic acid, and octanoic acid into the polyethylene to a concentration of 10% by mass. The second layer was made of recycled polyethylene (density 0.920 g / cm 3 The recycled polyethylene was then coated with a linear low-density polyethylene (density 0.931 g / cm 3 , MFR 1.0 g / 10 min, manufactured by The Dow Chemical Company, XUS60922.01) and a phenolic antioxidant (manufactured by BASF Japan Ltd., Irganox 1010) in an amount of 1500 ppm relative to the recycled polyethylene. 3 The anticorrosive film thus obtained had a thickness of 20 μm for the first layer, 50 μm for the second layer, and 10 μm for the third layer.

[0111] Example 2 An anticorrosive film was obtained in the same manner as in Example 1, except that the volatile anticorrosive agent was changed from the carboxylic acid ester compound to benzotriazole, a heterocyclic aromatic compound.

[0112] Comparative Example 1 A rust-preventing film was obtained in the same manner as in Example 1, except that ethanolamine, an amine-based volatile rust inhibitor, was used in place of the carboxylic acid ester compound as the masterbatch containing the volatile rust inhibitor.

[0113] Comparative Example 2 A rust-preventive film was obtained in the same manner as in Example 1, except that a phosphoric acid-based antioxidant (Irgafos 168, manufactured by BASF Japan Ltd.) was used as the antioxidant instead of the phenol-based antioxidant.

[0114] [Evaluation of Rust Prevention] Each of the anti-rust films obtained as described above was cut into a size of 150 mm × 200 mm to serve as an evaluation sample. A degreased iron plate (gray cast iron, FC200, degreased, shape: 40 mm × 60 mm × 10 mm) was covered with this sample and stored in a thermostatic chamber adjusted to 40°C and 90% RH for 20 days. The appearance of the iron plate was then evaluated according to the following criteria: ⊚: No rust or discoloration, or only rust spots and slight discoloration occurred; ◯: Rust occurred in less than 10% of the surface area of ​​the iron plate; Δ: Rust occurred in 10% to less than 50% of the surface area of ​​the iron plate; ×: Rust occurred in 50% or more of the surface area of ​​the iron plate. The evaluation results are shown in Table 1 below.

[0115] Furthermore, the resin compositions (recycled polyethylene, antioxidant, and volatile corrosion inhibitor) constituting the first layers of Example 1 and Comparative Example 1 were measured using a mass spectrometer (GCMS-QP2010, manufactured by Shimadzu Corporation) to evaluate the amount of volatile corrosion inhibitor reduced. Only the volatile corrosion inhibitor was measured as a blank. The measurement results are shown in FIG. 4.

[0116] The amount of reduced volatile corrosion inhibitor was also evaluated in the same manner as above for each of the resin compositions constituting the first layer of Example 1 and Comparative Example 2. The measurement results are shown in FIG.

[0117]

[0118] As is clear from the evaluation results in Table 1 and FIGS. 4 and 5, the rust-preventing film of the present disclosure has excellent rust-preventing performance despite using recycled resin.

[0119] [Example 3] A coextrusion inflation film-forming machine was used to produce a coextruded film having a three-layer structure of a first layer, a second layer, and a third layer. The first layer contained linear low-density polyethylene (density 0.916 g / cm 3 ). 3The second layer was made of a dry blend of polyethylene (NF444N, MFR 2.3 g / 10 min, manufactured by Japan Polyethylene) and a masterbatch of a volatile corrosion inhibitor at a ratio of 90:10 by mass. The masterbatch of the volatile corrosion inhibitor was prepared by kneading an ester compound of pentanoic acid, hexanoic acid, heptanoic acid, and octanoic acid into the linear low-density polyethylene to a concentration of 10% by mass. Recycled polyethylene (density 0.920 g / cm) was used as a component constituting the second layer. 3 The third layer was made of linear low-density polyethylene (density 0.931 g / cm 3 , MFR 1.0 g / 10 min, manufactured by The Dow Chemical Company, XUS60922.01) and a phenolic antioxidant (manufactured by BASF Japan Ltd., Irganox 1010) in an amount of 1500 ppm relative to the recycled polyethylene. 3 The anticorrosive film thus obtained had a thickness of 20 μm for the first layer, 50 μm for the second layer, and 10 μm for the third layer.

[0120] Example 4 An anticorrosive film was obtained in the same manner as in Example 3, except that ethanolamine, an amine-based volatile anticorrosive, was used as the masterbatch containing the volatile anticorrosive instead of the carboxylic acid ester compound.

[0121] Example 5 An anticorrosive film was obtained in the same manner as in Example 3, except that a phenolic antioxidant (Irgafos 168, manufactured by BASF Japan Ltd.) was used as the volatile anticorrosive agent instead of the carboxylic acid ester compound.

[0122] [Example 6] As the third layer, recycled polyethylene (density 0.920 g / cm 3 An anticorrosive film was obtained in the same manner as in Example 3, except that a cellulose ester copolymer (polysiloxane copolymer, MFR 1.0 g / 10 min, manufactured by The Dow Chemical Company, XUS60922.01) was used.

[0123] [Comparative Example 3] As the first layer, recycled polyethylene (density 0.920 g / cm 3The recycled polyethylene was dry-blended with a phenolic antioxidant (Irgafos 168, manufactured by BASF Japan) in an amount of 1500 ppm relative to the recycled polyethylene, and a masterbatch of the recycled polyethylene and a volatile corrosion inhibitor in a ratio of 96:4 by mass. The rust-preventing film was obtained in the same manner as in Example 3, except that the masterbatch of the volatile corrosion inhibitor was prepared by kneading an ester compound of pentanoic acid, hexanoic acid, heptanoic acid, and octanoic acid into the recycled polyethylene in an amount of 10% by mass.

[0124] Comparative Example 4 A rust-preventing film was obtained in the same manner as in Comparative Example 3, except that ethanolamine, an amine-based volatile rust inhibitor, was used in place of the carboxylic acid ester compound as the masterbatch containing the volatile rust inhibitor.

[0125] [Evaluation of Rust Prevention] Each of the anti-rust films obtained as described above was cut into a size of 150 mm × 200 mm to serve as an evaluation sample. A degreased iron plate (gray cast iron, FC200, degreased, shape: 40 mm × 60 mm × 10 mm) was covered with this sample and stored in a thermostatic chamber adjusted to 40°C and 90% RH for 20 days. The appearance of the iron plate was then evaluated according to the following criteria: ⊚: No rust or discoloration, or only rust spots and slight discoloration occurred; ◯: Rust occurred in less than 10% of the surface area of ​​the iron plate; Δ: Rust occurred in 10% to less than 50% of the surface area of ​​the iron plate; ×: Rust occurred in 50% or more of the surface area of ​​the iron plate. The evaluation results are shown in Table 2 below.

[0126] Furthermore, the resin compositions (recycled polyethylene, antioxidant, and volatile corrosion inhibitor) constituting the first layers of Example 3 and Comparative Example 3 were measured using a mass spectrometer (GCMS-QP2010, manufactured by Shimadzu Corporation) to evaluate the amount of volatile corrosion inhibitor reduced. Note that only the volatile corrosion inhibitor was measured as a blank. The measurement results are shown in FIG. 6.

[0127] The amount of reduced volatile corrosion inhibitor was also evaluated in the same manner as above for each of the resin compositions constituting the first layer of Example 4 and Comparative Example 4. The measurement results are shown in FIG.

[0128]

[0129] As is clear from the evaluation results in Table 2 and FIGS. 6 and 7, the rust-preventive film of the present invention has excellent rust-preventive properties despite using recycled resin.

[0130] [Example 7] A coextrusion inflation film-forming machine was used to produce a coextruded film having a three-layer structure of a first layer, a second layer, and a third layer. The first layer contained linear low-density polyethylene (density 0.916 g / cm 3 A dry blend of a volatile corrosion inhibitor masterbatch (SP2020, manufactured by Prime Polymer Co., Ltd., MFR 2.3 g / 10 min) and a volatile corrosion inhibitor masterbatch at a mass ratio of 96:4 was used. The volatile corrosion inhibitor masterbatch was prepared by kneading an ester compound of pentanoic acid, hexanoic acid, heptanoic acid, and octanoic acid into the linear low-density polyethylene to a concentration of 10% by mass. Recycled polyethylene (density 0.920 g / cm) was used as a component constituting the second layer. 3 The third layer was made of linear low-density polyethylene (density 0.931 g / cm 3, MFR 1.0 g / 10 min, manufactured by The Dow Chemical Company, XUS60922.01). 3 The anticorrosive film thus obtained had a thickness of 20 μm for the first layer, 50 μm for the second layer, and 10 μm for the third layer.

[0131] [Example 8] Recycled polyethylene (density 0.920 g / cm 3) was used as a component constituting the second layer. 3 , MFR 1.0 g / 10 min, Dow Chemical Company, XUS60922.01) and linear low-density polyethylene (density 0.921 g / cm 3 A co-extruded film was produced in the same manner as in Example 7, except that a dry blend of a first layer (20 μm), a second layer (50 μm), and a third layer (10 μm), each having a MFR of 2.0 g / 10 min and manufactured by Japan Polyethylene Corporation, was used in a 1:1 ratio by mass. The thicknesses of the layers in the resulting anti-corrosion film were: first layer 20 μm, second layer 50 μm, and third layer 10 μm.

[0132] [Example 9] Recycled polyethylene (density 0.920 g / cm 3) was used as a component constituting the first layer. 3 , MFR 1.0 g / 10 min, Dow Chemical Company, XUS60922.01) and linear low-density polyethylene (density 0.919 g / cm 3 A coextruded film was produced in the same manner as in Example 8, except that a dry blend of a volatile anticorrosive agent (UZ2021L, manufactured by Prime Polymer Co., Ltd., MFR 2.0 g / 10 min) and the masterbatch of the volatile anticorrosive agent described above was used in a ratio of 66:28:6 by mass, to obtain a rust-preventive film. The thicknesses of the layers of the obtained rust-preventive film were: first layer 20 μm, second layer 50 μm, and third layer 10 μm.

[0133] [Example 10] Recycled polyethylene (density 0.920 g / cm3) was used as a component constituting the first layer. 3 A coextruded film was produced in the same manner as in Example 9, to obtain a rust-preventive film, except that a dry blend of a volatile corrosion inhibitor (XUS60922.01, manufactured by The Dow Chemical Company, MFR 1.0 g / 10 min) and the masterbatch of the above-mentioned volatile rust inhibitor in a mass ratio of 96:4 was used. The thicknesses of the layers of the obtained rust-preventive film were: first layer 20 μm, second layer 60 μm, and third layer 10 μm.

[0134] Comparative Example 5 A bag (80 μm thick, 200 mm wide×300 mm high, manufactured by GSI Creos Co., Ltd., BCK082030) made of a film containing a volatile rust inhibitor was used.

[0135] [Rust Prevention Evaluation] Each of the rust prevention films obtained as described above was cut into a size of 150 mm x 200 mm to serve as an evaluation sample. A degreased iron plate (gray cast iron, FC200, degreased, shape: 40 mm x 60 mm x 10 mm) was covered with the film and stored in a thermostatic chamber adjusted to 40 °C and 90% RH for 20 days. The appearance of the iron plate was evaluated according to the following evaluation criteria. For Comparative Example 5, one side of the bag was cut into a size of 150 mm x 200 mm to serve as an evaluation sample. ◎: No rust or discoloration, or only rust spots and slight discoloration occurred. ◯: Rust occurred in less than 10% of the surface area of ​​the iron plate. △: Rust occurred in 10% to less than 50% of the surface area of ​​the iron plate. ×: Rust occurred in 50% or more of the surface area of ​​the iron plate. The evaluation results are shown in Table 3 below. A photograph of the appearance of the iron plate surface after storage in the thermostatic chamber for 20 days is shown in Figure 3.

[0136] [Evaluation of Puncture Resistance] Each anti-corrosion film was fixed in place with a jig, and a semicircular needle having a diameter of 1.0 mm and a tip radius of 0.5 mm was pierced from the third layer side of the anti-corrosion film at a test speed of 50 mm / min in accordance with JIS Z1707, and the maximum force (N) required for the needle to penetrate was measured. The measurement results are shown in Table 3 below.

[0137] [Mechanical Property Evaluation] Each rust-preventive film was cut into a size of 50 mm x 50 mm to serve as an evaluation sample. A tensile test was performed in accordance with JIS Z1702, applying a tensile load at a test speed of 300 mm / min until the evaluation sample broke, and the maximum load and the gauge line spacing at break were determined. The maximum load and the gauge line spacing at break were determined in both the MD and TD directions of the evaluation sample. The thickness of the evaluation sample was measured at a total of three locations, including the gauge line spacing, and the average value was used as the thickness. The measurement results are shown in Table 3 below.

[0138]

[0139] As is clear from the evaluation results in Table 3 and FIG. 8 , the rust-preventive film of the present invention, despite using recycled resin, has rust-preventive performance equal to or superior to that of a conventional single-layer rust-preventive film that does not use recycled resin.

[0140] 1 Anti-rust film 10 First layer 20 Second layer 30 Third layer

Claims

1. 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.

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

3. The rust-preventive film according to claim 1, wherein the antioxidant is contained in a proportion of 500 to 5000 ppm based on the recycled polyethylene.

4. A rust-preventive film comprising at least a first layer containing recycled polyethylene, a vaporizable rust inhibitor, and an antioxidant, and a second layer containing polyethylene, wherein the polyethylene constituting the second layer is at least one selected from the group consisting of recycled polyethylene and virgin polyethylene, and the first layer and the second layer are coextruded to form a film.

5. The recycled polyethylene has a density of 0.860 g / cm 3 or more and 0.932 g / cm 3 or less, and the rust-preventive film according to claim 4.

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, and the first layer and the second layer are coextruded to form a film.

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

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

9. The rust-preventive film according to claim 6, wherein the second layer further contains virgin polyethylene.

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

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

12. The polyethylene constituting the first layer has a density of 0.860 g / cm 3 or more and 0.932 g / cm 3 or less. The rust-preventive film according to claim 6.

13. The rust-preventive film according to claim 6, further comprising a third layer composed of polyethylene, and the first layer, the second layer, and the third layer are coextruded to form a film.

14. A rust-preventive film comprising a first layer, a second layer, and a third layer, wherein the first layer contains a vaporizable rust-preventive agent and polyethylene having a density of 0.860 g / cm 3 or more and 0.932 g / cm 3 or less, the second layer contains recycled polyethylene, the third layer contains polyethylene having the same density as or higher than the polyethylene constituting the first layer, and the first layer, the second layer, and the third layer are coextruded to form a film, the rust-preventive film.

15. The polyethylene that constitutes the first layer and has a density of 0.860 g / cm 3 or more and 0.932 g / cm 3 or less is at least one selected from low-density polyethylene and linear low-density polyethylene. The rust-preventive film according to any one of claims 5, 12, and 14.

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

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

18. The rust preventive film according to claim 14, wherein the second layer has a thickness 2 to 4 times that of the first layer.

19. The rust preventive film according to claim 14, wherein the second layer contains recycled polyethylene and virgin polyethylene.

20. The polyethylene having a density of 0.860 g / cm 3 or more and 0.932 g / cm 3 or less, which constitutes the first layer, is at least one selected from the group consisting of virgin polyethylene and recycled polyethylene. The rust preventive film according to claim 14.

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