Rust-preventive film

Abstract

To provide a rust-preventive film excellent in an antirust effect while using a recycled resin.SOLUTION: A rust-preventive film includes a rust-preventive agent-containing layer, a middle layer and an outermost layer. The rust-preventive agent-containing layer includes a volatile rust-preventive agent and a polyethylene with density of 0.860 g / cm3 to 0.932 g / cm3. The middle layer includes a recycled polyethylene. The outermost layer includes a polyethylene having density the same as or higher than that of the polyethylene included in the rust-preventive agent-containing layer. The rust-preventive agent-containing layer, the middle layer and the outermost layer are manufactured by a co-extrusion film production.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a rust preventive film, and more particularly, to a rust preventive film for wrapping metal members such as machine parts to suppress oxidation and rusting of the metal surface during storage, transportation, and shipping.

Background Art

[0002] Conventionally, when storing metal members for a long time, it has been common to apply a rust preventive oil and then perform packaging and storage as a measure to prevent rusting. For machine parts that cannot be rust-prevented by applying a rust preventive oil or the like, instead of the rust preventive oil, a method of packaging and storing with a vaporizable rust preventive agent or a rust preventive film formed by kneading a vaporizable rust preventive agent into a resin film is known.

[0003] In the rust preventive film using the above-described vaporizable rust preventive agent, since it is necessary to have air permeability so that the vaporizable rust preventive agent can vaporize, in a single-layer configuration, the vaporizable rust preventive agent volatilizes not only inside the package but also outside. Therefore, a multi-layer film configuration is adopted. For example, a multi-layer film in which a resin film containing a vaporizable rust preventive agent is laminated with a base film such as nylon has been proposed. According to such a multi-layer rust preventive film, it is said that diffusion or volatilization of the vaporizable rust preventive agent to the outer layer (atmosphere side) can be suppressed, and a high rust suppression effect can be maintained for a long time (for example, Patent Document 1).

[0004] In addition, a multi-layer film having a layer containing a vaporizable rust preventive agent in the innermost layer, a layer made of a gas barrier resin as an intermediate layer, and a base material layer as the outermost layer has also been proposed. According to the multi-layer film, it is known that the barrier property against the vaporized gas of the rust preventive agent, oxygen, or water vapor is improved by providing the intermediate layer.

[0005] Furthermore, a multi-layer rust preventive film in which a barrier film provided with a vapor deposition film and an organic coating layer on a base material is laminated on a sealant layer has been disclosed (for example, Patent Document 2).

Prior Art Documents

Patent Document

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] By the way, in recent years, from the viewpoint of reducing environmental load, it has been recommended to use recycled products. Also in the field of packaging films and the like, attempts have been made to actively use recycled resin products. However, although resins such as polyester and polyethylene have recycled resins on the market, at present, recycled products are not available for special gas barrier resins and the like.

[0008] Further, for example, recycled polyethylene resin contains impurities and various grades compared to virgin polyethylene resin, and it is known that it is necessary to raise the temperature when forming a film. Therefore, when trying to apply recycled resin to a rust preventive film, there has been a problem that thermal decomposition and volatilization of the vapor-phase rust preventive agent are promoted.

[0009] Therefore, an object of the present disclosure is to provide a rust preventive film having excellent rust preventive effect while using recycled resin.

Means for Solving the Problems

[0010] [1] A rust preventive film comprising a rust preventive agent-containing layer, an intermediate layer, and an outermost layer, wherein the rust preventive agent-containing layer contains a vapor-phase 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 intermediate layer contains recycled polyethylene, The outermost layer contains polyethylene having the same or higher density as the polyethylene constituting the rust preventive agent-containing layer. The rust preventive film is formed by coextrusion of the rust preventive agent-containing layer, the intermediate layer, and the outermost layer. Rust preventive film. [2] The polyethylene having a density of 0.860 g / cm 3 or more and 0.932 g / cm 3 or less, which constitutes the rust preventive agent-containing layer, is at least one selected from low-density polyethylene and linear low-density polyethylene. The rust preventive film according to [1]. [3] The vaporizable rust preventive agent is at least one selected from carboxylic acid ester-based rust preventive agents and alkanolamine-based rust preventive agents. The rust preventive film according to [1]. [4] The rust preventive agent-containing layer contains the vaporizable rust preventive agent in a proportion of 0.5% by mass or more and 15% by mass or less. The rust preventive film according to [1]. [5] The intermediate layer has a thickness that is 2 to 4 times the thickness of the rust preventive agent-containing layer. The rust preventive film according to [1]. [6] The intermediate layer contains recycled polyethylene and virgin polyethylene. The rust preventive film according to [1]. [7] The polyethylene having a density of 0.860 g / cm 3 or more and 0.932 g / cm 3 or less, which constitutes the rust preventive agent-containing layer, is virgin polyethylene. The rust preventive film according to [1]. [8] The polyethylene having a density of 0.860 g / cm 3 or more and 0.932 g / cm 3 or less, which constitutes the rust preventive agent-containing layer, is recycled polyethylene. The rust preventive film according to [1]. [9] The polyethylene having a density of 0.860 g / cm 3 or more and 0.932 g / cm 3 or less, which constitutes the rust preventive agent-containing layer, contains recycled polyethylene and virgin polyethylene. The rust preventive film according to [1].

Advantages of the Invention

[0011] According to the present disclosure, it is possible to provide a rust-preventive film that is excellent in rust-preventive effect while using recycled resin.

Brief Description of Drawings

[0012]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0013] In this specification, when a plurality of upper limit candidates and a plurality of lower limit candidates for a certain parameter are listed, the numerical range of that parameter may be constituted by combining any one upper limit candidate and any one lower limit candidate. As an example, an explanation will be given for the description "Parameter B is preferably A1 or more, more preferably A2 or more, still more preferably A3 or more. Parameter B is preferably A4 or less, more preferably A5 or less, still 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.

[0014] In this specification, polyethylene refers to a polymer in which the content ratio of ethylene-derived structural units exceeds 50 mol% in the total amount of structural units derived from polymerizable monomers. In this polymer, the content ratio of ethylene-derived structural units is preferably 70 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, and particularly preferably 95 mol% or more. The above content ratio is measured by nuclear magnetic resonance spectroscopy (NMR method).

[0015] 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)acrylate esters such as methyl (meth)acrylate and ethyl (meth)acrylate.

[0016] 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)acrylate copolymer.

[0017] In this specification, the density of polyethylene is as follows. The density of low-density polyethylene is 0.860 g / cm 3 or more and 0.932 g / cm 3 or less, more preferably 0.900 g / cm 3 or more and 0.932 g / cm 3 or less. The density of linear low-density polyethylene is 0.860 g / cm 3 or more and 0.932 g / cm 3 or less, more preferably 0.900 g / cm 3 or more and 0.932 g / cm 3 or less. The density of medium-density polyethylene exceeds 0.932 g / cm 3 and is 0.945 g / cm 3 or less. The density of high-density polyethylene exceeds 0.945 g / cm 3 and is preferably 0.965 g / cm 3 or less. The density of polyethylene is measured in accordance with JIS K7112-2:2023 (density gradient tube method, 23°C).

[0018] Low-density polyethylene is, for example, polyethylene obtained by polymerizing ethylene by the high-pressure polymerization method (high-pressure method 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.

[0019] Polyethylenes with different densities or degrees of branching are obtained by appropriately selecting the polymerization method. For example, as the polymerization catalyst, a multi-site catalyst such as a Ziegler-Natta catalyst or a single-site catalyst such as a metallocene catalyst is used, and polymerization is preferably carried out in one or two or more stages by any of the methods of gas-phase polymerization, slurry polymerization, solution polymerization, and high-pressure ionic polymerization.

[0020] The melt flow rate (MFR) of polyolefins such as polyethylene in this specification is described below. From the viewpoints of film-forming property and processability, the above MFR is preferably 0.1 g / 10 min or more, more preferably 0.3 g / 10 min or more, still 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, still more preferably 10 g / 10 min or less, and particularly preferably 5 g / 10 min or less. The above 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 the condition of a load of 2.16 kg in accordance with JIS K7210-1:2014. The measurement temperature of MFR is set according to the melting point of the polyolefin, etc., and is 190°C in the case of polyethylene.

[0021] In this specification, as the polyethylene, a resin material derived from biomass (hereinafter also referred to as "biomass polyethylene") may be used. The biomass material is, for example, a resin material obtained by using a biomass-derived raw material (specifically, a plant-derived raw material) as at least a part of the raw material. Since the biomass material is a carbon-neutral material, the environmental load due to the laminate or the packaging bag can be reduced.

[0022] In this specification, recycled polyethylene means polyethylene recycled from used polyethylene products by mechanical recycling or chemical recycling. Mechanical recycling generally means that a recovered polyethylene film or the like is pulverized, alkali-washed to remove dirt and foreign substances on the film surface, and then dried under high temperature and reduced pressure for a certain period of time to diffuse the contaminants remaining inside the film for decontamination, remove the dirt on the film, and return it to polyethylene again. Chemical recycling generally means a method of decomposing a recovered polyethylene film or the like to the monomer level and polymerizing the monomer again to obtain polyethylene. Further, in this specification, virgin polyethylene means polyethylene obtained by using a raw material derived from fossil fuel or a raw material derived from biomass, which is not recycled polyethylene.

[0023] Hereinafter, embodiments of the present disclosure will be described in detail. The present disclosure can be implemented in many different forms and is not construed as being limited to the description of the embodiments exemplified below. The drawings may schematically show the width, thickness, shape, etc. of each layer compared with the embodiments for clearer explanation, but are merely examples and do not limit the interpretation of the present disclosure. In this specification and each figure, elements that are the same as those already described with respect to the previously shown figures may be given the same reference numerals, and detailed description may be omitted as appropriate.

[0024] Hereinafter, embodiments of the rust-preventive film of the present disclosure will be described while appropriately using the drawings.

[0025] FIG. 1 is a schematic cross-sectional view showing an embodiment of the rust preventive film of the present disclosure. The rust preventive film 1 of the present disclosure is a co-extruded film including at least a rust preventive agent-containing layer 10, an intermediate layer 20, and an outermost layer 30 in this order. Note that the rust preventive film "including each layer in this order" means that the rust preventive film 1 includes each layer (10, 20, 30) in this order in the thickness direction of the rust preventive film 1.

[0026] The rust preventive agent-containing layer 10 of the rust preventive film 1 of the present disclosure is the layer that forms the innermost layer when the rust preventive film is used as a package for metal parts or the like, the outermost layer 30 is the layer that forms the outermost layer when used as a package, and the intermediate layer 20 is the layer provided between the rust preventive agent-containing layer 10 and the outermost layer 30. Hereinafter, each layer constituting the rust preventive film 1 of the present disclosure will be described.

[0027] [Rust preventive agent-containing layer] The rust preventive agent-containing layer constituting the rust preventive film of the present disclosure contains, as a resin component, polyethylene having a density of 0.860 g / cm 3 or more and 0.932 g / cm 3 or less as a main component. In the present disclosure, the "layer containing polyethylene as a main component" means a layer in which the content ratio of polyethylene in the layer is 50% by mass or more. The above content ratio is preferably 60% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more.

[0028] As the polyethylene having a density of 0.860 g / cm 3 or more and 0.932 g / cm 3 or less, as described above, low-density polyethylene or linear low-density polyethylene can be preferably used, and more preferably linear low-density polyethylene. As the resin component constituting the rust preventive agent-containing layer, it is more preferable to use linear low-density polyethylene having a density of 0.900 g / cm 3 or more and 0.932 g / cm 3 or less.

[0029] The density is 0.860 g / cm 3 or more and 0.932 g / cm 3 or less, the polyethylene may be virgin polyethylene only, or from the perspective of reducing environmental impact, recycled polyethylene may also be used. Further, a mixture of virgin polyethylene and recycled polyethylene may also be used.

[0030] The rust preventive agent-containing layer constituting the rust preventive film of the present disclosure contains a vaporizable rust preventive agent. By kneading a vaporizable rust preventive agent into polyethylene having a predetermined density as the resin component described above and forming a film, a rust preventive agent-containing layer can be formed.

[0031] As the vaporizable rust preventive agent, a conventionally known vaporizable rust preventive agent that volatilizes at 40°C to 60°C and exhibits a rust preventive effect can be used without particular limitation. For example, ammonium salts of aliphatic or aromatic acids, nitrites of amines, carboxylates of amines, chromates of amines, esters of carboxylic acids, heterocyclic compounds, thioureas, heterocyclic compounds having a mercapto group, a triazole ring, a pyrrole ring, a pyrazole ring, a thiazole ring, an imidazole ring, etc. can be mentioned. Among these, from the perspective of environmental adaptability, carboxylic acid esters and alkanolamines can be preferably used.

[0032] As the carboxylic acid ester-based rust inhibitor, fatty acid esters can preferably be used. Those having 6 or more and 20 or less carbon atoms in the fatty acid moiety of the fatty acid ester are preferred. If the number of carbon atoms is less than the above range, there is a risk that the boiling point is too close to the film-forming temperature, resulting in the generation of bubbles or the inability to form a film. Specific fatty acid esters include, for example, alcohol esters of the above fatty acids and glycerin fatty acid esters. Among glycerin fatty acid esters, glycerin tri-fatty acid esters are preferred, glycerin fatty acid esters are preferred, and glycerin tricaprylate is more preferred. Among the above fatty acids, it is preferable 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 tricaprylate.

[0033] Examples of alkanolamine-based vapor-phase 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, isopropylammonium-benzoate, isopropylammonium-carbamate, diisopropylammonium-nitrite, diisopropylammonium-caprylate, diisopropylammonium-laurate, diisopropylammonium-benzoate, diisopropylammonium-carbamate, benzylammonium-nitrite, benzylammonium-caprylate, benzylammonium-laurate, benzylammonium-benzoate, benzylammonium-carbamate, dibenzylammonium-nitrite, dibenzylammonium-caprylate, dibenzylammonium-laurate, dibenzylammonium-benzoate, dibenzylammonium-carbamate, and the like.

[0034] From the viewpoints of the diffusibility of the rust inhibitor and the film-forming property of the resin during extrusion, the addition amount of the vapor-phase rust inhibitor 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, based on the entire rust inhibitor-containing layer.

[0035] From the perspective of the diffusibility of the vaporizable rust inhibitor, etc., the thickness of the rust inhibitor-containing layer constituting the rust-proof film is preferably 3 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more. From the perspective 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 rust inhibitor-containing layer is, for example, 10 to 30 μm.

[0036] [Intermediate layer] The intermediate layer constituting the rust-proof film of the present disclosure is a layer provided between the rust inhibitor-containing layer and the outermost layer, and contains recycled polyethylene as the main component as the resin component. By using recycled polyethylene, it is possible to reduce the environmental load. Recycled polyethylene, especially mechanical recycled polyethylene, contains impurities and various grades as described above compared to virgin polyethylene resin. When using recycled polyethylene as the main component as the resin constituting the outermost layer and the rust inhibitor-containing layer, it is necessary to increase the film-forming temperature. Also, it is known that recycled polyethylene tends to generate fish eyes and wrinkles when forming a film compared to virgin polyethylene. In the present disclosure, by adopting a three-layer structure for the rust-proof film and using recycled polyethylene as the intermediate layer, while reducing the environmental load, the above problems are solved.

[0037] Recycled polyethylene (especially mechanical 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, 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.

[0038] The rust-preventive film of the present disclosure may contain virgin polyethylene in addition to recycled polyethylene as an intermediate layer. By appropriately adding virgin polyethylene, the film-forming property and processability can be improved. When the intermediate layer contains recycled polyethylene and virgin polyethylene, the content of virgin polyethylene is preferably more than 0% by mass and 50% by mass or less, more preferably 15% by mass or more and 35% by mass or less with respect to the entire intermediate layer.

[0039] When virgin polyethylene is contained in the intermediate layer, the virgin polyethylene is preferably low-density polyethylene of 0.860 g / cm 3 or more and 0.932 g / cm 3 or less, more preferably low-density polyethylene of 0.900 g / cm 3 or more and 0.932 g / cm 3 or less, or preferably linear low-density polyethylene of 0.860 g / cm 3 or more and 0.932 g / cm 3 or less, more preferably linear low-density polyethylene of 0.900 g / cm 3 or more and 0.932 g / cm 3 or less.

[0040] From the viewpoint of reducing environmental impact, the thickness of the intermediate layer constituting the rust-preventive film is preferably 20 μm or more, more preferably 30 μm or more, and even more preferably 40 μm or more. From the viewpoints of film-forming property 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 intermediate layer is, for example, 40 to 60 μm.

[0041] Further, the intermediate layer preferably has a thickness that is 2 to 4 times the thickness of the above-described rust preventive agent-containing layer. When using recycled polyethylene, it is necessary to set the melting temperature during film formation slightly higher (about 200 to 210°C) than that of virgin polyethylene. As will be described later, when adopting, for example, the inflation coextrusion film method for the rust preventive agent-containing layer, the intermediate layer, and the outermost layer, by setting the thickness of the intermediate layer to 2 to 4 times the thickness of the rust preventive agent-containing layer, while giving sufficient heat for the recycled polyethylene to melt during extrusion film formation, the surface of the rust preventive agent-containing layer located in the innermost layer can be air-cooled. Therefore, thermal degradation and volatilization of the vaporizable rust preventive agent in the rust preventive agent-containing layer can be suppressed. It is more preferable that the intermediate layer has a thickness that is 2 to 3 times the thickness of the rust preventive agent-containing layer.

[0042] [Outermost layer] The outermost layer of the rust preventive film of the present disclosure is the layer that constitutes the outermost layer when the rust preventive film is used as a package for metal parts or the like. By providing the rust preventive film with the outermost layer, diffusion of the vaporizable rust preventive agent contained in the rust preventive agent-containing layer into the atmosphere outside the rust preventive film can be suppressed. The outermost layer is mainly composed of polyethylene having the same or higher density as the polyethylene constituting the above-described rust preventive agent-containing layer as a resin component. For example, when the polyethylene constituting the rust preventive agent-containing layer is low-density polyethylene or linear low-density polyethylene, low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, or high-density polyethylene can be used for the outermost layer.

[0043] From the viewpoint of suppressing diffusion of the vaporizable rust preventive agent, it can be said that it is preferable to use polyethylene having a high density as the polyethylene constituting the outermost layer. However, from the viewpoints of film formability when forming the rust preventive film and curl suppression of the obtained film, etc., polyethylene should be selected so that the density difference between the polyethylene constituting the rust preventive agent-containing layer located in the innermost layer and the polyethylene constituting the outermost layer does not become large. From the viewpoints of suppressing diffusion of the vaporizable rust preventive agent and curl suppression, etc., it is preferable to use low-density polyethylene or linear low-density polyethylene having the same or higher density as the polyethylene constituting the rust preventive agent-containing layer.

[0044] Also, as the polyethylene constituting the outermost layer, either virgin polyethylene or recycled polyethylene may be used. From the perspective of reducing environmental impact, it can be said that it is preferable to use recycled polyethylene for the outermost layer as well. However, as described above, from the perspectives of suppressing the diffusion of the vaporizable rust preventive agent and suppressing curling, etc., 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 rust preventive agent-containing layer.

[0045] From the perspective of suppressing the diffusion of the vaporizable rust preventive agent, the thickness of the outermost layer constituting the rust preventive film is preferably 3 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more. From the perspectives of film-forming property 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 rust preventive agent-containing layer is, for example, 10 to 30 μm.

[0046] The total thickness of the rust preventive film of the present disclosure is appropriately adjusted according to the application, but 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.

[0047] [Method for manufacturing rust preventive film] The rust preventive film of the present disclosure can be obtained by coextrusion-molding the above-described rust preventive agent-containing layer, the intermediate layer, and the outermost layer. The coextruded film can be obtained by an inflation coextrusion film method using a circular die or a coextrusion film method using a T-die. Among these, according to the inflation coextrusion film method, since it is possible to perform melt coextrusion film formation at a lower temperature such as 200°C or lower, thermal decomposition and volatilization (vaporization) of the vaporizable rust preventive agent during film formation can be suppressed. In particular, when recycled polyethylene is used as the intermediate layer, it is necessary to set the melting temperature during film formation slightly higher (about 200 to 210°C) than virgin polyethylene. However, according to the inflation coextrusion film method, the melting temperature of the polyethylene in the rust preventive agent-containing layer can be set to 200°C or lower, and further, by air cooling during film formation, the influence of heat on the rust preventive agent-containing layer can be reduced. As a result, a rust preventive film excellent in rust preventive effect can be obtained while using recycled resin. Further, as in the present invention, by using a three-layer coextruded film made of polyethylene, the puncture resistance is improved compared to a single-layer film. Therefore, even when packaging a metal machine member having a protrusion, according to the rust preventive film of the present invention, it is possible to suppress breakage by machine parts.

[0048] When forming the rust preventive agent-containing layer, in order to enhance the dispersibility of the vaporizable rust preventive agent, a masterbatch containing the vaporizable rust preventive agent may be used, and coextrusion molding may be performed using a blend of the masterbatch and polyethylene having a predetermined density. The content ratio of the vaporizable rust preventive agent in the masterbatch is not particularly limited, but the masterbatch and polyethylene having a predetermined density may be blended so that the content ratio of the vaporizable rust preventive agent in the rust preventive agent-containing layer falls within the above-described range.

[0049] In addition, the rust preventive film of the present disclosure may have various additives added to any one or more of the layers as long as the properties are not impaired. Examples of the additives include antioxidants, slip agents, plasticizers, ultraviolet stabilizers, anti-coloring agents, matting agents, deodorants, flame retardants, weathering agents, antistatic agents, yarn friction reducers, mold release agents, ion exchangers, antiblocking agents, and coloring pigments.

[0050] The rust preventive film of the present disclosure can be used as a packaging material for wrapping metal members such as machine parts. There are no particular restrictions on the shape and form of the packaging material. In the form of a film, it can also wrap the contents, and the rust preventive film can be bent or overlapped and heat-sealed to form a bag shape.

Example

[0051] Hereinafter, the laminate of the present disclosure will be described more specifically by way of examples. However, the laminate of the present disclosure is not limited to the following examples.

[0052] [Example 1] Using a coextrusion inflation film forming machine, a coextruded film having a three-layer structure of a rust preventive agent-containing layer / intermediate layer / outermost layer was formed. As components constituting the rust preventive agent-containing layer, linear low-density polyethylene (density 0.916 g / cm 3 , MFR 2.3 g / 10 min, manufactured by Prime Polymer Co., Ltd., SP2020) and a masterbatch of a vaporizable rust preventive agent were dry-blended at a ratio of 96:4 on a mass basis. As the masterbatch of the vaporizable rust preventive agent, an ester compound of pentanoic acid, hexanoic acid, heptanoic acid and octanoic acid kneaded into the above linear low-density polyethylene to be 10% on a mass basis was used. As components constituting the intermediate layer, recycled polyethylene (density 0.920 g / cm 3 , MFR 1.0 g / 10 min, manufactured by Dow Chemical Company, XUS60922.01) was used. As components constituting the outermost layer, linear low-density polyethylene (density 0.931 g / cm 3 , MFR 2.1 g / 10 min, manufactured by Prime Polymer Co., Ltd., UZ3520) was used. The thickness of each layer of the rust preventive film obtained as described above was 20 μm for the rust preventive agent-containing layer / 50 μm for the intermediate layer / 10 μm for the outermost layer.

[0053] [Example 2] As components constituting the intermediate layer, recycled polyethylene (density 0.920 g / cm 3 , MFR 1.0 g / 10 min, manufactured by Dow Chemical Company, XUS60922.01) and linear low-density polyethylene (density 0.921 g / cm 3 , MFR 2.0 g / 10 min, manufactured by Japan Polyethylene Corporation) were dry-blended at a ratio of 1:1 by mass, and a co-extruded film was formed in the same manner as in Example 1 except for this, and a rust-preventive film was obtained. The thickness of each layer of the obtained rust-preventive film was 20 μm for the rust-preventive agent-containing layer / 50 μm for the intermediate layer / 10 μm for the outermost layer.

[0054] [Example 3] As components constituting the rust-preventive agent-containing layer, recycled polyethylene (density 0.920 g / cm 3 , MFR 1.0 g / 10 min, manufactured by Dow Chemical Company, XUS60922.01), linear low-density polyethylene (density 0.919 g / cm 3 , MFR 2.0 g / 10 min, manufactured by Prime Polymer Co., Ltd., UZ2021L), and the masterbatch of the above-described vaporizable rust-preventive agent were dry-blended at a ratio of 66:28:6 by mass, and a co-extruded film was formed in the same manner as in Example 2 except for using this, and a rust-preventive film was obtained. The thickness of each layer of the obtained rust-preventive film was 20 μm for the rust-preventive agent-containing layer / 50 μm for the intermediate layer / 10 μm for the outermost layer.

[0055] [Example 4] As components constituting the rust-preventive agent-containing layer, recycled polyethylene (density 0.920 g / cm 3 , MFR 1.0 g / 10 min, manufactured by Dow Chemical Company, XUS60922.01) and the masterbatch of the above-described vaporizable rust-preventive agent were dry-blended at a ratio of 96:4 by mass, and a co-extruded film was formed in the same manner as in Example 3 except for using this, and a rust-preventive film was obtained. The thickness of each layer of the obtained rust-preventive film was 20 μm for the rust-preventive agent-containing layer / 60 μm for the intermediate layer / 10 μm for the outermost layer.

[0056] [Comparative Example 1] A bag made of a film incorporating a vapor-phase rust preventive agent (thickness: 80 μm, width: 200 mm × height: 300 mm, manufactured by GSI Creos Corporation, BCK082030) was used.

[0057] [Rust prevention evaluation] Each rust-preventive film obtained as described above was cut into a size of 150 mm × 200 mm and used as a sample for evaluation. A degreased iron plate (gray cast iron, FC200, degreased, shape: 40 mm × 60 mm × 10 mm) was coated and stored in a thermostatic chamber adjusted to 40 °C and 90% RH for 20 days. Then, the appearance of the iron plate was evaluated according to the following evaluation criteria. For Comparative Example 1, a piece cut from one side of the bag to a size of 150 mm × 200 mm was used as the evaluation sample. ◎: No rust or discoloration, or only pitting rust and slight discoloration occurred 〇: Rust occurred at less than 10% of the area of the iron plate surface △: Rust occurred at 10% or more and less than 50% of the area of the iron plate surface ×: Rust occurred at 50% or more of the area of the iron plate surface The evaluation results were as shown in Table 1 below. In addition, a photograph of the appearance of the iron plate surface after being stored in the thermostatic chamber for 20 days is shown in Fig. 1.

[0058] [Puncture resistance evaluation] Each rust-preventive film was fixed with a jig, and in accordance with JIS Z1707, a semicircular needle with a diameter of 1.0 mm and a tip shape radius of 0.5 mm was pierced from the outermost layer side of the rust-preventive film at a test speed of 50 mm / min, and the maximum force (N) until the needle penetrated was measured. The measurement results were as shown in Table 1 below.

[0059] [Mechanical property evaluation] Each rust-preventive film cut into a size of 50 mm × 50 mm was used as a sample for evaluation. In accordance with JIS Z1702, a tensile test was conducted at a test speed of 300 mm / min by applying a tensile load until the evaluation sample broke, and the maximum load and the gauge length at break were determined. The maximum load and the gauge length at break were determined in both the MD direction and the TD direction of the evaluation sample. The thickness of the evaluation sample was measured at a total of three locations including the gauge section, and the average value was taken as the thickness. The measurement results were as shown in Table 1 below.

[0060]

Table 1

[0061] As is clear from the evaluation results in Table 1 and Figure 2, it can be seen that the rust-preventive film of the present invention has rust-preventive performance equivalent to or higher than that of a single-layer rust-preventive film that does not use a recycled resin while using a recycled resin.

Explanation of Signs

[0062] 1 Rust-preventive film 10 Rust inhibitor-containing layer 20 Intermediate layer 30 Outermost layer

Claims

1. A rust preventive film comprising a rust preventive agent-containing layer, an intermediate layer, and an outermost layer, The rust preventive agent-containing 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, and wherein the intermediate layer contains recycled polyethylene, the outermost layer contains polyethylene having the same or higher density as the polyethylene constituting the rust preventive agent-containing layer, and the rust preventive agent-containing layer, the intermediate layer, and the outermost layer are coextruded to form a film. Rust preventive film.

2. The polyethylene having a density of 0.860 g / cm 3 or more and 0.932 g / cm 3 or less, which constitutes the rust preventive agent-containing layer, is at least one selected from low-density polyethylene and linear low-density polyethylene. The rust preventive film according to claim 1.

3. The rust preventive film according to claim 1, wherein the volatile rust preventive agent is at least one selected from carboxylic acid ester-based rust preventive agents and alkanolamine-based rust preventive agents.

4. The rust preventive film according to claim 1, wherein the rust preventive agent-containing layer contains 2 to 10% by mass of the volatile rust preventive agent.

5. The rust preventive film according to claim 1, wherein the intermediate layer has a thickness 2 to 4 times that of the rust preventive agent-containing layer.

6. The rust preventive film according to claim 1, wherein the intermediate layer contains recycled polyethylene and virgin polyethylene.

7. The polyethylene having a density of 0.860 g / cm 3 or more and 0.932 g / cm 3 or less, which constitutes the rust preventive agent-containing layer, is virgin polyethylene. The rust preventive film according to claim 1.

8. The polyethylene that constitutes the rust preventive agent-containing layer and has a density of 0.860 g / cm 3 or more and 0.932 g / cm 3 or less is recycled polyethylene. The rust preventive film according to claim 1.

9. The polyethylene constituting the rust preventive agent-containing layer, having a density of 0.860 g / cm 3 or more and 0.932 g / cm 3 or less, and containing recycled polyethylene and virgin polyethylene, the rust preventive film according to claim 1.

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