Rust-prevention film

Abstract

To provide a rust-prevention film which is excellent in production suitability, and can suppress occurrence of rust in contents during conveyance and long-term storage while having simple layer constitution, and a rust-prevention packaging material and a rust-prevention package produced using the rust-prevention film.SOLUTION: A rust-prevention film of a single layer or multiple layers contains at least a rust-prevention agent and a binder resin, in which the rust-prevention agent contains one or two or more kinds selected from the group consisting of a fatty acid, a metal fatty acid and a fatty acid ester.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an anti-rust film that inhibits the generation of rust on packaged contents, and to a packaging material and a package produced using the anti-rust film. The rust-preventive film according to the present invention can be applied to products in various fields, and in particular can be suitably used as a packaging material for housing metal products such as screws, shafts, and metal plates for automobiles, as well as electrical components, etc. [Background technology]

[0002] Packaging materials are being developed for the purpose of transporting and long-term storage of metal products consisting of metal materials or metal parts, etc., and there is a demand for packaging materials that have higher and more stable rust prevention properties and that have a simple layer structure and can be produced by a simple manufacturing process so as to maintain the functions and properties of the metal products contained therein. Patent Documents 1 to 3 describe packaging laminates in which a resin contains a highly volatile rust inhibitor that volatilizes at room temperature and exhibits a rust-preventing effect for the purpose of preventing rust from occurring in the contents of metal products. However, these laminates require an exterior seal, and there are concerns that if the vaporized rust inhibitor adheres to the contents, it may cause effects other than the rust-preventing effect, such as deterioration of the contents or functional impairment. In addition, removing the adhered rust inhibitor is time-consuming, so that the applications of these laminates are limited. Therefore, there is a demand for rust-preventive films that do not use volatile rust inhibitors. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2010-254350 A [Patent Document 2] JP 2007-308726 A [Patent Document 3] JP 2010-052751 A Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention aims to solve the above problems and to provide an anti-rust film that is easy to manufacture and has a simple layer structure, yet can prevent the occurrence of rust in the contents during transportation and long-term storage, as well as an anti-rust packaging material and an anti-rust package made using the anti-rust film. [Means for solving the problem]

[0005] As a result of extensive investigations, the present inventors have found that an anti-rust film containing at least the anti-rust agent defined in the present invention and a binder resin can achieve the above object. That is, the present invention is characterized in the following points. 1. A single-layer rust-preventive film containing at least a rust inhibitor and a binder resin, The rust-preventive film is characterized in that the rust-preventive agent contains at least one or more kinds selected from the group consisting of fatty acids, metallic fatty acids, and fatty acid esters. 2. A multi-layer anti-rust film having at least an anti-rust layer, The rust-preventive layer contains a rust inhibitor and a binder resin, The rust inhibitor contains at least one or more selected from the group consisting of fatty acids, metallic fatty acids, and fatty acid esters, A rust-preventive film, characterized in that a layer containing a thermoplastic resin is laminated on one or both sides of the rust-preventive layer. 3. The rust-preventive film according to claim 2, wherein the rust-preventive film is a co-extrusion film. film. 4. The anti-rust film according to claim 2 or 3, further comprising an intermediate layer. 5. The rust-preventive film according to any one of 1 to 4 above, wherein the fatty acid, metallic fatty acid, or fatty acid ester has a fatty acid moiety with 6 or more and 20 or less carbon atoms. 6. The rust-preventive film according to any one of 1 to 5 above, wherein the rust-preventive agent further contains an antioxidant and an alkaline agent that exhibits alkalinity and neutralizes acidic substances. 7. The rust-preventive film according to item 6 above, wherein the antioxidant contains a phenol-based antioxidant and / or a phosphorus-based antioxidant. 8. The rust-preventive film according to 6 or 7 above, characterized in that the alkaline agent contains one or more compounds selected from the group consisting of alkali metal compounds, alkaline earth metal compounds, and aluminum compounds. 9. An anti-rust packaging material comprising the anti-rust film according to any one of 1 to 8 above. 10. A rust-proof packaging body, characterized by being made of the rust-proof packaging material described in 9 above. Effect of the Invention

[0006] The rust-preventive film of the present invention and the rust-preventive packaging material and rust-preventive package prepared using the rust-preventive film solve the above-mentioned problems, and provide a rust-preventive film that is excellent in manufacturability and has a simple layer structure, yet can suppress the occurrence of rust in the contents during transportation and long-term storage, as well as a rust-preventive packaging material and rust-preventive package prepared using the rust-preventive film. [Brief description of the drawings]

[0007] [Figure 1] 1 is a schematic cross-sectional view showing an example of a layer structure of the rust-preventive film of the present invention. [Diagram 2] FIG. 2 is a schematic cross-sectional view showing an example of another embodiment of the layer structure of the rust-preventive film of the present invention.

[0008] In each drawing, the size and ratio of the components may be changed or exaggerated for ease of understanding. Also, for ease of understanding, parts that are unnecessary for the explanation or repeated reference numerals may be omitted. Although not shown in the drawings, an adhesive layer may be provided between each layer. Furthermore, if necessary, in order to strengthen the adhesive strength (adhesion strength) between each layer, the laminated surfaces of each layer may be previously subjected to a physical surface treatment such as corona discharge treatment, ozone treatment, plasma treatment, glow discharge treatment, sandblasting treatment, etc., or a chemical surface treatment such as oxidation treatment using chemicals. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The anti-rust film, the anti-rust packaging material, and the anti-rust package of the present invention will be described in more detail below. Specific examples will be given, but the present invention is not limited thereto. In the present invention, the terms film and sheet are used synonymously.

[0010] <Anti-rust film> The rust-preventive film of the present invention is a resin film that contains at least a rust inhibitor and a binder resin and has heat sealability. The rust-preventive film of the present invention may be a single-layer film or a multi-layer film. The rust inhibitor used in the rust-preventive film of the present invention preferably contains two or more kinds selected from the group consisting of fatty acids, metallic fatty acids, and fatty acid esters. It is preferable that the anti-rust agent contains two or more selected from the group consisting of "an alkaline agent for neutralizing acidic substances by exhibiting an acidity," "an antioxidant," and "an acid gas adsorbent for adsorbing acidic gases." By using two or more kinds of anti-rust agents in combination, the anti-rust effect can be efficiently exhibited. Hereinafter, fatty acids, metallic fatty acids, and fatty acid esters are collectively referred to as "fatty acids." In order to inhibit the occurrence of rust, it is effective to adsorb acidic gases entering from the outside or present in the internal space of the package onto an anti-rust film, or to attach or coat the surface of the contents with an anti-rust agent to make the surface of the contents water-repellent, prevent oxidation of the surface of the contents, or neutralize acidic gases that come into contact with the surface of the contents. By using the above-mentioned anti-rust agents in combination, these methods can be used in combination to efficiently achieve anti-rust effects.

[0011] The thickness of the anti-rust film is not particularly limited, but is preferably 25 μm or more and 200 μm or less. If it is thinner than the above range, the rigidity is too low, it is easily torn, and it is difficult to achieve a balance between sufficient support, anti-rust effect, and heat sealability, while if it is thicker than the above range, the rigidity is too high, and it is easy to deteriorate the usability as a packaging material.

[0012] The transparency of the anti-rust film can be increased depending on the application. The total light transmittance of the highly transparent anti-rust film is preferably 50% or more. The transparency of the anti-rust packaging material made of a highly transparent anti-rust film is also high, and the anti-rust packaging body made from the highly transparent anti-rust packaging material allows the contents, labels attached to the contents, letters and seals engraved on the contents, etc. to be easily seen.

[0013] The rust-preventive film may contain various plastic compounding agents and additives for the purpose of improving or modifying, for example, processability, heat resistance, weather resistance, mechanical properties, dimensional stability, oxidation resistance, slipperiness, release properties, flame retardancy, mold resistance, electrical properties, strength, etc. The content of these may range from a very small amount to several tens of percent, and may be arbitrarily determined depending on the purpose. In the above, typical additives that may be contained include, for example, antiblocking agents, lubricants, crosslinking agents, antioxidants, ultraviolet absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, pigments, modifying resins, and the like.

[0014] When the rust-preventive film of the present invention is a single-layer rust-preventive film, it contains at least a rust inhibitor and a binder resin in one layer. When the binder resin has heat-sealing properties, one or both surfaces of the single-layer rust-preventive film can have heat-sealing properties. The rust inhibitor may be uniformly dispersed in one layer, or may be dispersed with a concentration gradient. For example, when a concentration gradient is provided so that a large amount of rust inhibitor is present near the surface of one side and a small amount of rust inhibitor is present near the surface of the other side, the surface of the side with a large amount of rust inhibitor is likely to efficiently exhibit rust prevention properties, and the surface of the side with a small amount of rust inhibitor has high heat sealability. The heat sealability of both sides of the rust-preventive film can also be improved by lowering the concentration of the rust-preventive agent overall or by increasing the concentration of the rust-preventive agent in the center of the layer. The content of the rust inhibitor in the rust-preventive film is preferably 0.1 mass % or more and 50 mass % or less. If it is less than the above range, it is difficult to achieve a sufficient rust-preventive effect, and if it is more than the above range, the film-forming property and heat-sealing property are likely to be inferior.

[0015] When the rust-preventive film of the present invention is a multi-layer rust-preventive film, it has at least a rust-preventive layer containing a rust inhibitor and a binder resin. The binder resin is a thermoplastic resin, and when the binder resin has heat-sealing properties, one or both sides of the rust-preventive layer can have heat-sealing properties. It is also preferable that a layer containing a thermoplastic resin is laminated on one or both sides of the rust-preventive layer. The multi-layered anti-rust film may have, for example, an intermediate layer and an outer layer that exhibit various functions depending on the application. In this case, the anti-rust film is preferably laminated in the order of the anti-rust layer, the intermediate layer, and the outer layer. The layers may be laminated with an adhesive layer between them. The rust-preventive film has an anti-rust layer and thus inhibits the occurrence of rust on the contents. For example, if the thermoplastic resin contained in the outer layer is a heat-sealable resin, the multi-layer rust-preventive film can have heat-sealability. The rust inhibitor may be uniformly dispersed in the rust-preventive layer, or may be dispersed with a concentration gradient. For example, when a concentration gradient is provided so that a large amount of rust inhibitor is present near the surface of one side and a small amount of rust inhibitor is present near the surface of the other side, the surface of the side with a large amount of rust inhibitor is likely to efficiently exhibit rust prevention properties, and the surface of the side with a small amount of rust inhibitor has high heat sealability. The adhesion of both interfaces of the rust-preventive layer can be improved by lowering the concentration of the rust-preventive agent overall or by increasing the concentration of the rust-preventive agent in the center of the rust-preventive layer. The content of the rust inhibitor in the rust-preventive layer is preferably 0.1 mass % or more and 50 mass % or less. If it is less than the above range, it is difficult to achieve a sufficient rust-preventive effect, and if it is more than the above range, the film-forming property and heat-sealing property are likely to be deteriorated.

[0016] The multi-layered anti-rust film preferably has an anti-rust layer on one or both surfaces. The presence of the anti-rust layer on the surface makes it easier to apply or coat the anti-rust material on the surface of the contents. In addition, when the surface is an anticorrosive layer, this means that the whole or part of the anticorrosive layer is exposed to the surface.

[0017] <Rust inhibitor> The rust inhibitor is a compound that inhibits rust from occurring on the contents packaged in the rust-preventive film of the present invention. The rust inhibitor of the present invention can inhibit the generation of rust by remaining inside the rust-preventive film of the present invention and adsorbing acidic gases, or by adhering from the rust-preventive film of the present invention to the surface of the packaged contents by evaporation, scattering or contact transfer, and neutralizing acidic substances on the surface of the contents, repelling water to inhibit adhesion of moisture, and inhibiting oxidation.

[0018] In the present invention, the rust inhibitor preferably contains two or more selected from the group consisting of "an alkaline agent that exhibits alkalinity and neutralizes acidic substances", "an antioxidant", "one or more selected from the group consisting of fatty acids, metallic fatty acids, and fatty acid esters", and "an acidic gas adsorbent for adsorbing acidic gases". When two or more types are used in combination, the different effects of acid gas adsorption, acid substance neutralization, water repellency, oxidation inhibition, etc. contribute synergistically, thereby improving rust prevention properties synergistically. Preferred combinations of the rust inhibitors contained therein are, for example, an antioxidant and an alkaline agent, an antioxidant and a fatty acid, an antioxidant, an alkaline agent and a fatty acid, an alkaline agent and a fatty acid, an alkaline agent and an acidic gas adsorbent, a fatty acid and an acidic gas adsorbent, etc.

[0019] Details of each type of rust inhibitor contained in the rust-preventive film of the present invention are as follows.

[0020] [Alkaline agent] The alkaline agent in the present invention is a compound that is alkaline in itself, and adheres to the surface of the packaged contents to neutralize acidic substances that cause rust, thereby suppressing the occurrence of rust. The alkaline agent may be an alkali metal compound, an alkaline earth metal compound, or an aluminum compound. In the present invention, the alkali metal is a broad definition of alkali metal, and includes metal elements in Group 1. Among these, Li, Na and K are preferred. In addition, alkaline earth metals refer to alkaline earth metals in a broad sense, and include the Group 2 metallic elements Be, Mg, Ca, SrBa, and Ra.

[0021] Examples of the alkali metal compound include alkali metal oxides, alkali metal chlorides, and alkali metal hydroxides, and specific examples of the alkali metal compound include Li2O, Na2O, K2O, LiCl, LiOH, etc. Among these, Na2O and K2O are preferred.

[0022] Examples of the alkaline earth metal compound include alkaline earth metal oxides, alkaline earth metal chlorides, alkaline earth metal hydroxides, etc., and specific examples of the alkaline earth metal compound include BeO, MgO, CaO, SrO, BaO, RaO, MgCl2, CaCl2, Mg(OH)2, Ca(OH)2, etc. Among these, MgO, CaO, Mg(OH)2, Ca(OH)2, etc. are preferred.

[0023] Specific examples of the aluminum compound include Al2O3, Al(OH)3, etc. Among these, Al2O3 is preferred.

[0024] Among the above specific alkaline agents, it is preferable to use one or more selected from the group consisting of MgO, CaO, Mg(OH)2, Ca(OH)2, and Al2O3.

[0025] The alkaline agent is used in powder form, and the number-based average particle size of the powder is preferably 0.1 μm or more and 20 μm or less. If the average particle size is smaller than the above range, the alkaline agent is likely to aggregate, and if it is larger than the above range, the surface area is small, which may result in poor rust prevention. The content of the alkaline agent contained in the single-layer anti-rust film or the anti-rust layer of the multi-layer anti-rust film is preferably 15 mass % or more and 50 mass % or less. If it is less than the above range, it is difficult to achieve a sufficient anti-rust effect, and if it is more than the above range, the film-forming property and heat-sealing property are likely to be inferior.

[0026] [Antioxidants] The antioxidant in the present invention adheres to the surface of the packaged contents and can inhibit the generation of rust due to oxidation of the surface of the contents. As the antioxidant, any known antioxidant used in packaging materials can be used, but phenol-based antioxidants and phosphorus-based antioxidants are preferred, and among these, those having a hydrophilic group and a hydrophobic group are more preferred.

[0027] A specific preferred phenol-based antioxidant is pentaerythritol tetrakis[3-(3,5-ditertiarybutyl-4-hydroxyphenyl)propionate]. Specific examples of the phosphorus-based antioxidant include tris(2,4-ditertiarybutylphenyl)phosphite and 2,4,8,10-tetratertiarybutyl-6-(3-(3-methyl-4-hydroxy-5-tertiarybutylphenyl)propoxy)dibenzo(d,f)(1,3,2)dioxaphosphepine.

[0028] The content of the antioxidant contained in the single-layer rust-proofing film or the rust-proofing layer of the multi-layer rust-proofing film is preferably 0.1 mass % or more and 15 mass % or less. If it is less than the above range, it is difficult to achieve a sufficient rust-proofing effect, and if it is more than the above range, the rust-proofing effect is not significantly improved and the film-forming property and heat-sealing property are likely to be deteriorated, which is not preferable.

[0029] [Fatty acids] The fatty acids in the present invention adhere to the surface of the packaged contents and exhibit a water-repellent effect, thereby preventing moisture, which causes rust, from adhering to the surface of the contents, thereby inhibiting the occurrence of rust. Specific examples of fatty acids include fatty acids, metallic fatty acids, and fatty acid esters. It is believed that fatty acids exhibit water repellency because the aliphatic chain portion functions as a hydrophobic group and the carboxylic acid portion functions as a hydrophilic group, with the hydrophilic group adhering to the surface of the contents and the hydrophobic portion adhering facing outward. The fatty acid composition preferably has a carbon number in the fatty acid portion of 6 to 20. If the carbon number is less than the above range, the boiling point may be too close to the film-forming temperature, which may cause bubbles to form or may make it impossible to form a film, whereas if the carbon number is greater than the above range, the anticorrosive film may be less likely to evaporate, scatter, or adhere to the surface of the packaged contents by contact transfer. Specific examples of fatty acids include caproic acid, heptanoic acid, nonanoic acid, octanoic acid, decanoic acid, undecylic acid, lauric acid, stearic acid, nonadecylic acid, and arachidic acid.

[0030] Specific examples of metallic fatty acids include alkali metal salts and alkaline earth metal salts of the above fatty acids, with Ca salts being preferred. Specific examples of fatty acid esters include alcohol esters of the above-mentioned fatty acids and glycerin fatty acid esters. The glycerin fatty acid ester is preferably glycerin trifatty acid ester, more preferably glycerin fatty acid ester, and more preferably glycerin tricaprylic acid ester. 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 tricaprylic acid ester. The content of fatty acids contained in the single-layer rust-proofing film or the rust-proofing layer of the multi-layer rust-proofing film is preferably 0.1 mass % or more and 30 mass % or less. If it is less than the above range, it is difficult to achieve a sufficient rust-proofing effect, and if it is more than the above range, the rust-proofing effect is not significantly improved and the film-forming property and heat-sealing property are likely to be deteriorated, which is not preferable.

[0031] [Acid gas adsorbent] The acid gas adsorbent in the present invention is SO x , NO x It is possible to adsorb acidic gases such as carbon dioxide and inhibit the surface of the packaged contents from rusting due to these acidic gases. By containing an acid gas adsorbent, the anti-rust film can prevent these acid gases from penetrating the anti-rust film from the outside of the package and entering the package, and can adsorb these acid gases present in the content storage section inside the package, thereby reducing their concentration. The acidic gas adsorbent preferably contains one or more types selected from the group consisting of hydrophobic zeolite, metal-supported zeolite, and amino group-supported porous material. The acid gas adsorbent may have any external shape, such as a sphere, a rod, an ellipse, or the like, and may be in any form, such as a powder, a lump, or a granule. From the viewpoints of uniform dispersibility, kneading characteristics, film-forming properties, and the like, when dispersed in a resin, a powder form is preferred.

[0032] The acid gas adsorbent is used in powder form, and the average particle size of the powder based on the number of particles is preferably 0.1 μm or more and 20 μm or less. Here, the average particle size is a value measured by a dynamic light scattering method. If the average particle size is smaller than the above range, the acid gas adsorbent is likely to aggregate, and if it is larger than the above range, the surface area is small, so that there is a risk of poor rust prevention. The content of the acid gas adsorbent contained in the rust-preventive layer of a single-layer rust-preventive film or a multilayer rust-preventive film is preferably 0.1 mass % or more and 30 mass % or less. If it is less than the above range, it is difficult to achieve a sufficient rust-preventive effect. If it is more than the above range, the rust-preventive effect is not significantly improved and the film-forming property and heat-sealing property are likely to be deteriorated, which is not preferable.

[0033] (Hydrophobic Zeolite) Hydrophobic zeolites are porous bodies, and the higher the molar ratio of SiO2 / Al2O3, which are the constituent components, the higher the hydrophobicity becomes. Hydrophobic zeolites having a molar ratio of SiO2 / Al2O3 of 30 / 1 to 10,000 / 1 are preferred. High hydrophobicity improves the ability to adsorb acid gases with low polarity without adsorbing water vapor with high polarity. In the present invention, a hydrophilic zeolite having a molar ratio within the above range is preferably used in view of the balance between moisture absorption performance and availability.

[0034] (Metal-supported zeolite) Metal-supported zeolite is a zeolite that supports a metal other than Si or Al. The supported metal is considered to be actually supported on the zeolite in the form of a metal oxide or in the form of metal atoms themselves. In the present invention, the term "metal-supported zeolite" is used as a general term for both metal oxide-supported zeolites and metal atom-supported zeolites. It is believed that when gas components that cause rust come into contact with metal-supported zeolite, the gas components undergo one of several reactions, such as ionization, bonding, decomposition, oxidation, or reduction, and lose their ability to cause rust. The metal species to be supported is preferably one that is less reactive with moisture and has a smaller tendency to ionize than iron. Specifically, one or more metals selected from the group consisting of copper, zinc, silver, platinum, etc. are preferred, and one or more metals selected from the group consisting of copper, zinc, and silver are more preferred. The zeolite to be supported may be either a hydrophilic zeolite or a hydrophobic zeolite.

[0035] (Porous material carrying amino groups) The amino group-supporting porous material is a porous material having a chemical adsorbent having an amino group supported thereon. As the supporting method, a publicly known or commonly used supporting method can be applied. For example, the chemical adsorbent can be supported by impregnating the porous body with a solution containing the chemical adsorbent and drying it. In the amino group-supported porous material, the amino group portion selectively reacts with and adsorbs aldehyde compounds and the like, and physical adsorption properties can also be expected for the pores of the porous material. As the porous material on which the amino group is supported, any compound having a large number of pores on its surface can be used, and inorganic porous materials are preferred, such as zeolite, silicon dioxide, silicates, activated carbon, titania, inorganic phosphates such as calcium phosphate, alumina, aluminum hydroxide, magnesium hydroxide, and mixtures thereof. In particular, aluminum hydroxide, zeolite, and silicates are preferably used from the viewpoint of safety, since they have a porous state with pores of an effective size relative to the molecular size or cluster size of the substance to be adsorbed.

[0036] [How to disperse the rust inhibitor] The rust inhibitor is preferably incorporated via a masterbatch in which the rust inhibitor is melt-blended with a thermoplastic resin. Specifically, it is preferable to prepare a master batch by melt blending the rust inhibitor with a thermoplastic resin at a relatively high concentration, and then dry blending the master batch with components such as a binder resin to obtain the rust inhibitor concentration. The rust inhibitor and the thermoplastic resin to be melt blended may each be one type or two or more types, and one master batch may contain one type or two or more types of rust inhibitor. The content of the rust inhibitor in the master batch is preferably 3% by mass or more and 95% by mass or less, more preferably 20% by mass or more and 90% by mass or less, and even more preferably 30% by mass or more and 70% by mass or less. Within the above range, it is easy to contain a necessary and sufficient amount of the rust inhibitor in a dispersed state. The above thermoplastic resin may be the same as or different from the binder resin contained in the rust-preventive layer.

[0037] <Binder resin> The binder resin contained in the layer containing the rust inhibitor is preferably a resin having an affinity suitable for dispersing the rust inhibitor and excellent film-forming properties, and more preferably a resin having heat sealability.

[0038] Specific examples of the binder resin include polyolefin resins, polyester resins, polyamide resins, polyaramid resins, polycarbonate resins, polyacetal resins, fluorine resins, ethylene-vinyl acetate copolymers, ethylene-vinyl alcohol copolymers (EVOH), polyvinyl alcohol, polyacrylonitrile, etc. These resins may be used alone or in combination of two or more. Among these resins, polyolefin resins are preferred from the viewpoint of film-forming properties.

[0039] Specific examples of polyolefin resins include polyethylene resins, polypropylene resins, unsaturated carboxylic acid modified resins of polyolefin resins, cyclic polyolefin resins, cyclic olefin copolymers, etc. As unsaturated carboxylic acids, it is preferable to use acrylic acid, methacrylic acid, maleic anhydride, fumaric acid, etc. These polyolefin resins may be used alone or in combination of two or more, or in a multilayer structure containing different types of resins. These copolymerized unsaturated carboxylic acids may be used alone or in combination of two or more. Among these polyolefin resins, polyethylene resins are preferred from the viewpoint of film-forming properties.

[0040] Specific examples of polyethylene resins include low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), metallocene polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-ethyl (meth)acrylate copolymer, ethylene-(meth)acrylic acid copolymer, ethylene-propylene copolymer, methylpentene polymer, unsaturated carboxylic acid modified resin of polyethylene polyolefin resin, etc. As the unsaturated carboxylic acid, it is preferable to use acrylic acid, methacrylic acid, maleic anhydride, fumaric acid, etc. Among the above polyethylene-based resins, low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE) are more preferred, and linear low-density polyethylene (LLDPE) is even more preferred. These polyethylene-based resins may be used alone or in combination of two or more.

[0041] <Anti-rust layer> The rust-preventive layer is a layer in a multi-layer rust-preventive film that contains a rust inhibitor and a binder resin. The binder resin contained in the rust-preventive layer is made of a thermoplastic resin, and may or may not have heat-sealing properties. When the binder resin has heat-sealing properties, it is preferable that the binder resin contains a heat-sealing resin, or the binder resin may contain a heat-sealing resin. The rust-preventive layer may be a single layer containing two or more types of rust inhibitors, or may be composed of two or more layers containing different types or contents of rust inhibitors. The anticorrosive layer is preferably laminated on the surface of the anticorrosive film having a multi-layer structure, since the anticorrosive layer is laminated on the surface, the anticorrosive effect can be easily exhibited.

[0042] The content of the rust inhibitor in the rust-preventive layer is preferably 0.1% by mass or more and 50% by mass or less. If the content is less than the above range, it is difficult to achieve a sufficient rust-preventive effect, and if the content is more than the above range, the film-forming property and heat-sealing property are likely to be deteriorated. The thickness of the rust-preventive layer can be appropriately set by those skilled in the art, but is preferably 5 μm or more and 150 μm or less, more preferably 10 μm or more and 100 μm or less, and even more preferably 10 μm or more and 50 μm or less. If it is thinner than the above range, there is a risk that it will not be able to exhibit a sufficient rust-preventive effect, and even if it is thicker than the above unevenness, the rust-preventive effect will not be improved much, and the rigidity of the entire rust-preventive film will be too strong, making it difficult to use.

[0043] <Middle Class> The intermediate layer may have various kinds of layers that can impart various mechanical, physical and chemical functions to the rust-preventive film, such as support, rigidity, flexibility and pinhole resistance. For example, the inclusion of a water vapor barrier layer can prevent moisture from entering the content storage section within the package, or can adsorb moisture in the content storage section to reduce humidity, thereby preventing condensation and providing the contents with excellent rust prevention properties. Specific examples of the water vapor barrier layer include an inorganic vapor deposition layer and a metal foil layer.

[0044] Examples of resins for improving supportability include tough thermoplastic resins such as polyolefin resins, polyester resins, polyamide resins, polyaramid resins, polycarbonate resins, polyacetal resins, fluorine resins, ethylene-vinyl acetate copolymers, ethylene-vinyl alcohol copolymers (EVOH), polyvinyl alcohol, polyacrylonitrile, etc. These resins may be used alone or in combination of two or more, or may be used in multiple layers containing different types of resins. Among these resins, polyolefin resins are preferred from the viewpoint of film-forming properties.

[0045] Specific examples of polyolefin resins include polyethylene resins, polypropylene resins, unsaturated carboxylic acid modified resins of polyolefin resins, cyclic polyolefin resins, cyclic olefin copolymers, etc. As unsaturated carboxylic acids, it is preferable to use acrylic acid, methacrylic acid, maleic anhydride, fumaric acid, etc. These polyolefin resins may be used alone or in combination of two or more, or in a multilayer structure containing different types of resins. These copolymerized unsaturated carboxylic acids may be used alone or in combination of two or more. Among these polyolefin resins, polyethylene resins are preferred from the viewpoint of film-forming properties.

[0046] Specific examples of polyethylene resins include low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), metallocene polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-ethyl (meth)acrylate copolymer, ethylene-(meth)acrylic acid copolymer, ethylene-propylene copolymer, methylpentene polymer, unsaturated carboxylic acid modified resin of polyethylene polyolefin resin, etc. As the unsaturated carboxylic acid, it is preferable to use acrylic acid, methacrylic acid, maleic anhydride, fumaric acid, etc. Among the above polyethylene-based resins, low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE) are more preferred, and linear low-density polyethylene (LLDPE) is even more preferred. These polyethylene-based resins may be used alone. Two or more of these may be mixed and used.

[0047] The thickness of the intermediate layer can be appropriately set by a person skilled in the art, but when the purpose is to impart appropriate strength and stiffness to the laminate, the thickness is preferably 5 μm or more and 100 μm or less, and more preferably 10 μm or more and 50 μm or less.

[0048] <Outer layer> The outer surface layer is a layer containing a thermoplastic resin. As the thermoplastic resin used for the outer layer, many kinds of resins can be used within a range that does not significantly adversely affect the heat sealability and film formability of the entire film. Specific examples of the thermoplastic resin include polyolefin resins such as general-purpose polyethylene, polypropylene, methylpentene polymer, and acid-modified polyolefin resins, and mixtures of these resins, but are not limited to these resins, and the type of thermoplastic resin can be selected depending on the purpose. The outer surface layer is preferably laminated on the surface of the rust-preventive film having a multi-layer structure. The thickness of the outer layer is not particularly limited, but is preferably 10 μm or more and 100 μm or less. If it is within the above range, there is little risk of it having a significant adverse effect on the heat sealability and film formability of the entire film.

[0049] (Heat sealable resin) The heat-sealable resin that can be used in the rust-preventive film of the present invention is not particularly limited, and any known heat-sealable resin can be used, so long as it can be melted and fused by heat. Specific examples of heat-sealable resins include polyethylene, low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, metallocene polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ionomer resin, ethylene-ethyl (meth)acrylate copolymer, ethylene-(meth)acrylic acid copolymer, ethylene-propylene copolymer, methylpentene polymer, polyolefin resins obtained by modifying polyolefin resins such as polyethylene or polypropylene with unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic anhydride, fumaric acid, and the like, terpolymer resins of ethylene-(meth)acrylic acid ester-unsaturated carboxylic acid, cyclic polyolefin resins, cyclic olefin copolymers, polyethylene terephthalate (PET), polyacrylonitrile (PAN), and the like. Among these, polyolefin-based resins are preferred, and among polyolefin-based resins, polyethylene-based resins are more preferred, and among polyethylene-based resins, low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE) are even more preferred, with linear low-density polyethylene (LLDPE) being particularly preferred.

[0050] <Adhesive layer> There are no particular limitations on the adhesive used in the adhesive layer, and adhesives for DL ​​(dry lamination), adhesives for EC (extrusion coating), adhesives for non-solvent lamination, any anchor coating agent, and the like can be used. The adhesive may be of any of the following types: heat-curable, ultraviolet-curable, and electron-beam-curable types; and may be in any form, such as aqueous, solution, emulsion, and dispersion types. The adhesive may be in any form, such as film / sheet, powder, and solid. The adhesive mechanism may be any of the following types: chemical reaction, solvent volatilization, thermal melting, and thermal pressure.

[0051] Examples of components that form such an adhesive layer include polyvinyl acetate adhesives such as polyvinyl acetate and vinyl acetate-ethylene copolymers, polyacrylic acid adhesives made of copolymers of polyacrylic acid and polystyrene, polyester, polyvinyl acetate, etc., and cyanoacrylate adhesives. Examples of adhesives include ethylene copolymer-based adhesives made of copolymers of ethylene and monomers such as vinyl acetate, ethyl acrylate, acrylic acid, and methacrylic acid, cellulose-based adhesives, polyurethane-based adhesives, polyester-based adhesives, polyamide-based adhesives, polyimide-based adhesives, polyolefin-based adhesives such as LDPE, amino resin-based adhesives made of urea resin or melamine resin, phenolic resin-based adhesives, epoxy-based adhesives, reactive (meth)acrylic adhesives, elastomer-based adhesives made of chloroprene rubber, nitrile rubber, styrene-butadiene rubber, etc., silicone-based adhesives, and inorganic adhesives made of alkali metal silicates, low-melting point glass, etc.

[0052] <How to make anti-rust film> The method for producing the rust-preventive film of the present invention will be described below. The production method shown below is only one example and is not intended to limit the present invention. The rust-preventive film can be produced by any method, such as a T-die extrusion method, an extrusion inflation method, or the like. When the rust-proof film has a multi-layer structure, the lamination of each layer can be carried out by any method used in the production of ordinary packaging materials, such as a wet lamination method, a dry lamination method, a solventless dry lamination method, an extrusion lamination method, a co-extrusion lamination method, a T-die co-extrusion method, a co-extrusion inflation method, or the like. Of the above, the multi-layer rust-preventive film is preferably a co-extrusion film produced by a method including co-extrusion. When the above lamination is performed, if necessary, the surface of each layer may be subjected to a pretreatment such as corona treatment, ozone treatment, etc. Also, anchor coating agents such as isocyanate (urethane), polyethyleneimine, polybutadiene, and organic titanium, or anchor coating agents such as polyurethane, polyacrylic, polyester, epoxy, polyvinyl acetate, cellulose, and other lamination adhesives may be used as desired.

[0053] For example, the case of producing an anticorrosive film by an inflation method will be described. When the rust-preventive film is a single layer, first, a resin composition for forming the rust-preventive film is prepared, and the rust-preventive film is produced by inflation film formation. When the rust-preventive film is multi-layered, first, resin compositions for forming the rust-preventive layer, intermediate layer, and outer surface layer are prepared. Then, the rust-preventive layer, intermediate layer, and outer surface layer are co-extruded and laminated by inflation film formation to produce a multi-layered rust-preventive film. Then, an aging treatment may be performed as necessary. In this manner, a laminate for packaging liquid contents or a packaging material for liquid contents can be produced. The obtained rust-preventive film may then be stretched uniaxially or biaxially, if necessary.

[0054] The anti-rust film can be subjected to secondary processing for the purpose of imparting surface functions such as chemical functions, electrical functions, magnetic functions, mechanical functions, friction / wear / lubrication functions, optical functions, thermal functions, and biocompatibility. Examples of secondary processing include embossing, painting, gluing, printing, metallizing (plating, etc.), machining, surface treatment (antistatic treatment, corona discharge treatment, plasma treatment, photochromic treatment, physical vapor deposition, chemical vapor deposition, coating, etc.) The rust-resistant film can also be subjected to lamination (dry lamination or extrusion lamination), bag making, and other post-treatment processes.

[0055] <Rust-resistant packaging materials> The rust-preventive packaging material of the present invention is a packaging material produced from the rust-preventive film of the present invention, and may further comprise layers having various functions, if necessary. The rust-proof packaging material has the same rust-proofing properties as the rust-proof film and can be used, for example, as a stretch film.

[0056] <Rust-proof packaging> The rust-preventive packaging body of the present invention is a packaging body made from the rust-preventive packaging material of the present invention. There is no particular limitation on the shape or form of the rust-proof packaging body of the present invention, and the rust-proof packaging material can be folded, layered to encase the contents, or heat sealed to form various shapes or forms, and added value can be added by printing decoration. For example, a pouch-shaped rust-proof package can be produced using less rust-proof packaging material than a bottle-shaped rust-proof package, and is effective in saving resources.

[0057] A pouch-shaped rust-proof package can be produced, for example, by folding a rust-proof package material in half, or by preparing two sheets of the rust-proof package material, overlapping them with the heat-sealable layers facing each other, and then heat-sealing the peripheral edges using a heat seal type, such as a side seal type, two-sided seal type, three-sided seal type, four-sided seal type, envelope seal type, grommet seal type (pillow seal type), pleated seal type, flat bottom seal type, square bottom seal type, or gusset type. In the above, the heat sealing can be performed by a known method such as bar sealing, rotary roll sealing, belt sealing, impulse sealing, high frequency sealing, ultrasonic sealing, etc.

[0058] In the rust-preventive package, it is preferable that the rust-preventive layer of the rust-preventive packaging material is positioned on the inside of the rust-preventive package, and the outer layer is positioned on the inside. By packaging in this manner, the rust-proof packaging can efficiently prevent the penetration of acid gases from the outside and prevent the contents from rusting by applying a rust inhibitor to the surface of the contents. When preparing the rust-proof package, the package may be sealed while the air inside the package is being sucked out or while the content space is being replaced with air having a low oxygen content or low humidity. EXAMPLES

[0059] The present invention will be described in more detail with reference to the following examples and comparative examples, but the present invention is not limited to these examples. Details of the raw materials used in the examples are as follows.

[0060] [Fatty acids] · Fatty acid 1: Heptanoic acid manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. · Fatty acid 2: Stearic acid manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Fatty acid 3: Decanoic acid manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Fatty acid 4: Lauric acid (Fujifilm Wako Pure Chemical Industries, Ltd.) Fatty acid 5: Stearic acid manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Metal fatty acid 1: Calcium stearate manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Fatty acid ester 1: Triglyceride, Actor M2 manufactured by Riken Vitamin Co., Ltd.

[0061] [Antioxidants] Antioxidant 1: A060, a phenolic antioxidant manufactured by ADEKA Corporation. · Antioxidant 2: Phosphorus-based antioxidant 2112 manufactured by ADEKA Corporation. Antioxidant 3: A-612R, a phenol + phosphorus mixed antioxidant manufactured by Adeka Corporation G.

[0062] [Alkaline agent] Alkaline agent 1: Calcium oxide, HAL-J, manufactured by Yoshizawa Lime Industry Co., Ltd. Average particle size: 1 to 2 μm.

[0063] [Binder resin, thermoplastic resin] LLDPE1: Prime Polymer LLDPE, Evolu SP2020. Density 0.916g / cm 3 , MFR=2.0g / 10min. LDPE1: LDPE manufactured by Japan Polyethylene Co., Ltd., Novatec LC520. Density 0.923g / cm 3 , MFR3.6g / 10min.

[0064] <Preparation of Masterbatch> The masterbatch was prepared as follows. [Preparation of Masterbatch 1] LDPE 1 and fatty acid 1 were melt-blended in the ratio shown below to obtain master batch 1 (MB1). LDPE1 95 parts by mass Fatty acid 1 5 parts by mass

[0065] [Adjustment of Masterbatches 2 to 11] According to the formulations in Table 1, melt blending was carried out in the same manner as for Masterbatch 1 to obtain Masterbatches 2 to 11 (MB2 to 11).

[0066] [Table 1]

[0067] <Example> Anticorrosive films containing the anticorrosive agents were prepared and various evaluations were carried out.

[0068] [Example 1] MB1 and LLDPE1 were dry blended in the following ratio to obtain a resin composition for the rust-preventive layer. MB1 20 parts by mass LLDPE1 80 parts by mass The obtained resin composition for the rust-preventive layer was formed into a film by inflation film formation at 160° C. to obtain a rust-preventive film (thickness: 30 μm) consisting of only the rust-preventive layer, and various evaluations were then carried out.

[0069] [Example 2] MB1, MB8, MB11 and LLDPE1 were dry blended in the ratio shown below to obtain a resin composition for an anticorrosive layer. MB1 10 parts by mass MB8 10 parts by mass MB11 40 parts by mass LLDPE1 40 parts by mass Using the above obtained anticorrosive layer resin composition, an anticorrosive film (30 μm thick) consisting of only an anticorrosive layer was obtained in the same manner as in Example 1. Various evaluations were then carried out in the same manner as in Example 1.

[0070] [Example 3] MB1 and LLDPE1 were dry blended in the following ratio to obtain a resin composition for the rust-preventive layer. MB1 20 parts by mass LLDPE1 80 parts by mass The above obtained anticorrosive layer resin composition and LLDPE1 were formed into a film and laminated by inflation film formation at 160° C. to obtain an anticorrosive film (60 μm thick) having the following three-layer structure. Various evaluations were then carried out in the same manner as in Example 1. Layer structure: Anti-rust layer / middle layer (LLDPE1) / outer layer (LLDPE1) = 15μm thick / 30μm thick / 15μm thick

[0071] [Examples 4 to 28] Masterbatches were selected according to the descriptions in Tables 2 to 7, and the same procedure as in Example 3 was carried out to prepare rust-preventive films having a three-layer structure, which were then similarly evaluated.

[0072] [Comparative Example 1] A three-layer anticorrosive film was prepared in the same manner as in Example 3, except that the anticorrosive layer was formed using only LLDPE1, and was evaluated in the same manner.

[0073] [Summary of results] The rust-preventive films of Examples 1 to 28 of the present invention exhibited good film-forming properties, heat-sealing properties, and rust prevention properties. On the other hand, the comparative film containing no rust inhibitor exhibited poor rust prevention properties.

[0074] [Table 2]

[0075] [Table 3]

[0076] [Table 4]

[0077] [Table 5]

[0078] [Table 6]

[0079] [Table 7]

[0080] <Evaluation method> [Film forming property] The appearance of the anticorrosive film was observed with the naked eye, and the presence or absence of defects was evaluated according to the following evaluation criteria. ◯: The rust-preventive film had no wrinkles, bumps, peeling, etc. ×: The rust-preventive film had wrinkles, bumps, peeling, etc.

[0081] [Heat sealability] The rust-preventive film was cut into 100 mm x 100 mm pieces, and if it had a heat-sealable outer layer, the outer layers were placed facing each other and overlapped. After that, using a heat seal tester (Tester Sangyo Co., Ltd.: TP-701-A), an area of ​​1 cm x 10 cm was heat-sealed so that the ends were not heat-sealed and were split into two, and the film was then cut into 15 mm wide strips to prepare test pieces for measuring heat seal strength. Each bifurcated end of this test piece was attached to a tensile tester and pulled to peel off the heat-sealed portion, the heat-seal strength (N / 15 mm width) was measured, and the pass / fail rating was determined according to the following pass / fail criteria. (Heat seal conditions) Temperature: 160℃ Pressure: 1kgf / cm 2 Time: 1 second (Tensile strength test conditions) Test speed: 300mm / min Load range: 50N (Pass / Fail criteria) ○: 30N / 15mm or more, passed. ×: Less than 30N / 15mm, failing.

[0082] [Rust prevention] The rust-preventive film was cut into 100 mm x 100 mm pieces, and if the film had heat-sealable outer layers, the outer layers were placed facing each other and overlapped. After that, the laminate was sealed on all four sides using an impulse sealer to produce a 100 mm x 100 mm pouch. Next, the pouch was filled with the metal pieces described below and stored in a thermostatic chamber adjusted to 60° C. and 90% RH for 14 days, and the change in appearance was evaluated according to the following evaluation criteria. (metal piece) Steel plate: Cold-rolled steel plate (SPCC), 50mm x 50mm x 1mm, degreased. Copper plate: Tough pitch copper plate (C1100P-1 / 4H), 50 mm x 50 mm x 1 mm, degreased. (Evaluation Criteria) ◎: No rust or discoloration, or only spots of rust and slight discoloration. ○: Rust occurred on less than 10% of the test piece area. △: Rust occurred on 10% or more but less than 50% of the test piece area. ×: Rust occurred on 50% or more of the test piece area. [Explanation of symbols]

[0083] 1. Anti-rust film 2. Anti-rust packaging materials 3 Anti-rust layer 3a Rust inhibitor 4. Middle Tier 5 Outer layer

Claims

1. A single-layer or multi-layer rust-preventive film containing at least a rust inhibitor and a binder resin, The rust inhibitor contains at least one or more selected from the group consisting of fatty acids, metal fatty acids, and fatty acid esters, and an acidic gas adsorbent. The rust inhibitor is contained in the surface layer of the rust-preventive film. A rust-preventive film characterized by the following features.

2. The rust-preventive film according to claim 1, characterized in that the rust-preventive film is a co-extruded film.

3. The rust-preventive film according to claim 1 or 2, wherein the rust-preventive film further comprises an intermediate layer.

4. The rust-preventive film according to any one of claims 1 to 3, characterized in that the number of carbon atoms in the fatty acid portion of the aforementioned fatty acid, metal fatty acid, or fatty acid ester is 6 or more and 20 or less.

5. The rust-preventive film according to any one of claims 1 to 4, characterized in that the acidic gas adsorbent contains a metal-supported zeolite.

6. The rust-preventive film according to any one of claims 1 to 5, characterized in that the rust inhibitor further contains an antioxidant and an alkaline agent that exhibits alkalinity and neutralizes acidic substances.

7. The rust-preventive film according to claim 6, characterized in that the antioxidant contains a phenolic antioxidant and / or a phosphorus-based antioxidant.

8. The rust-preventive film according to claim 6 or 7, characterized in that the alkaline agent contains one or more selected from the group consisting of alkali metal compounds, alkaline earth metal compounds, and aluminum compounds.

9. A rust-preventive packaging material characterized by comprising a rust-preventive film according to any one of claims 1 to 8.

10. A rust-preventive packaging body characterized by being made of the rust-preventive packaging material described in claim 9.

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