Multilayer rust preventive film for packaging

Abstract

The present invention addresses the problem of surely preventing the generation of rust in details of an article or the like by means of a rust preventive film in storing the article with use of a bag or the like that uses the rust preventive film. The present invention also addresses the problem of preventing adhesion of deposition powder of a rust preventive agent on the surface of the article even after storage, and improving workability by easy handling in use. As a solution, the present invention provides a multilayer rust preventive film for packaging, which has an inner surface-side rust preventive agent-containing resin layer that faces the content side at the time of packaging and an outer surface-side rust preventive agent-containing resin layer, and which satisfies the following A or B. A: The inner surface-side rust preventive agent-containing resin layer and / or the outer surface-side rust preventive agent-containing resin layer contains dicarboxylic acid ammonium salt particles that have an average particle diameter of 5.0 µm or less and a maximum particle diameter of 10.0 µm or less. B: Only the outer surface-side rust preventive agent-containing resin layer contains dicarboxylic acid ammonium salt particles that have an average particle diameter of more than 5.0 µm but not more than 20.0 µm and a maximum particle diameter of more than 10.0 µm but not more than 100.0 µm.

Description

Laminated anti-rust film for packaging

[0001] The present invention relates to a laminated anticorrosive film for packaging.

[0002] As described in Patent Documents 1 and 2, anti-rust films made of polyethylene film containing an amine salt or sodium salt as a rust inhibitor are known. By using such known anti-rust films to package a metal item to be preserved, the item can be preserved for a certain period of time without rusting. Known anti-rust films made primarily of polyethylene are primarily intended to improve rust prevention. However, when an item is packaged and preserved in a bag-shaped anti-rust film under high temperature and humidity conditions for a long period of time, the vaporized anti-rust agent may precipitate as powder inside the package, resulting in the deposition of the powder on the surface of the item. As a result, the user may need to take the time to wipe off the precipitated powder before using the item as is or assembling it with another item.

[0003] JP 2016-169311 A JP 2019-131267 A

[0004] The present invention aims to reliably prevent the occurrence of rust in the details of an article through the rust-preventive film when storing the article using a bag or the like using the rust-preventive film, and to prevent the adhesion of precipitated powder of the rust inhibitor to the surface of the article even after storage, thereby facilitating handling during use and improving workability.

[0005] The present inventors have conducted extensive research to solve the above problems, and have found that the problems can be solved by the following means, leading to the completion of the present invention. 1. A laminated anti-rust film for packaging having an anti-rust agent-containing resin layer on an inner surface facing the contents during packaging and an anti-rust agent-containing resin layer on an outer surface, which satisfies either A or B below. A. The anti-rust agent-containing resin layer on the inner surface and / or the anti-rust agent-containing resin layer on the outer surface contains ammonium dicarboxylate salt particles having an average particle size of 5.0 μm or less and a maximum particle size of 10.0 μm or less. B. Only the anti-rust agent-containing resin layer on the outer surface contains ammonium dicarboxylate salt particles having an average particle size of more than 5.0 μm and not more than 20.0 μm and a maximum particle size of more than 10.0 μm and not more than 100.0 μm. 2. 2. The laminated rust-preventive film for packaging according to 1, wherein the ammonium dicarboxylate salt is one or more selected from ammonium adipate, ammonium succinate, ammonium sebacate, ammonium phthalate, ammonium isophthalate, and ammonium terephthalate. 3. The laminated rust-preventive film for packaging according to 1 or 2, wherein the rust-preventive-agent-containing resin layer on the inner surface side contains one or more selected from a metal salt of an aliphatic carboxylic acid, a metal salt of an inorganic acid, a benzotriazole-based compound, and a tolyltriazole-based compound.

[0006] The laminated rust-preventive film for packaging of the present invention prevents powder resulting from the rust inhibitor from adhering to the article over time, thereby facilitating handling and improving workability during use of the article. Furthermore, when a metal is packaged, the film can effectively prevent the metal surface from rusting, regardless of whether the metal comes into contact with the inner surface of the rust-preventive film.

[0007] The present invention will be described below. In this specification, sodium carboxylate and the like may be referred to as carboxylate Na and the like.

[0008] [Laminated Rust-Preventive Film for Packaging of the Present Invention] (Structure of Laminated Rust-Preventive Film for Packaging) The present invention provides a laminated rust-preventive film for packaging having an inner rust-preventive agent-containing resin layer facing the contents during packaging and an outer rust-preventive agent-containing resin layer, and satisfying either A or B below. A. The inner rust-preventive agent-containing resin layer and / or the outer rust-preventive agent-containing resin layer contain ammonium dicarboxylate salt particles having an average particle size of 5.0 μm or less and a maximum particle size of 10.0 μm or less. B. Only the outer rust-preventive agent-containing resin layer contains ammonium dicarboxylate salt particles having an average particle size of more than 5.0 μm and not more than 20.0 μm and a maximum particle size of more than 10.0 μm and not more than 100.0 μm. The laminated rust-preventive film for packaging of the present invention has two or more rust-preventive agent-containing resin layers. The laminated rust-preventive film for packaging of the present invention is processed into a bag-shaped product, a metal product to be rust-prevented is placed inside, and the bag-shaped product is sealed and airtight. Alternatively, the metal product is packaged and sealed without being bagged. Among the multiple layers, the rust inhibitor-containing resin layer on the inner surface facing the metal product when the metal product is packaged as the content is sometimes referred to as the "inner layer," and the rust inhibitor-containing resin layer on the outer surface facing the inner layer is sometimes referred to as the "outer layer." Furthermore, in the ammonium dicarboxylate salt particles and other particles of the present invention, the entire surface of the particle is coated with a resin. These inner and outer rust inhibitor-containing resin layers contain a known rust inhibitor other than ammonium dicarboxylate salt particles as a rust inhibitor. By using such a known rust inhibitor as the inner and / or outer layer of the rust inhibitor-containing resin layer of the present invention, even if the layer containing the known rust inhibitor is different, excellent rust prevention performance can be achieved for many types of metals by providing a layer containing ammonium dicarboxylate salt particles of a specific particle size according to the present invention.

[0009] The inner layer is a rust inhibitor-containing resin layer on the innermost side, facing the contents when the metal product is packaged. It may also be a rust inhibitor-containing resin layer that directly faces the metal product. Furthermore, a separate innermost layer may be provided further inside the inner layer relative to the metal product when packaged. This separate innermost layer does not contain a rust inhibitor. When an innermost layer is provided, the inner rust inhibitor-containing resin layer in the present invention is located between the outer layer, which is the rust inhibitor-containing resin layer on the outer side, and the innermost layer. The outer layer is located outside the inner layer when the product is packaged.

[0010] The outer layer is not a layer directly facing the metal product to be packaged, but must be between the inner layer and the outer layer. An intermediate layer may be provided as a separate layer between the inner and outer layers. The outermost layer may be provided on the opposite side of the outer layer from the inner layer. If the laminated rust-preventive film for packaging of the present invention has all of the above-mentioned innermost layer, optional intermediate layer, and optional outermost layer, the film will have the innermost layer, inner layer, intermediate layer, outer layer, and outermost layer, in this order from the side of the product to be packaged during packaging. The innermost layer, intermediate layer, and outermost layer may be provided independently and optionally, or may not be provided. The innermost layer and intermediate layer do not contain a rust inhibitor, and the outermost layer may or may not contain ammonium dicarboxylate salt particles or other known rust inhibitors. Furthermore, the outermost layer of the laminated rust-preventive film for packaging of the present invention may be a laminated rust-preventive film having a layer made of a composition other than the laminated rust-preventive film for packaging of the present invention laminated thereon. In the present invention, in the case of the above A, the outer layer does not have a rust inhibitor-containing resin layer containing ammonium dicarboxylate particles as defined in the above B. In the case of the above B, the inner layer does not contain ammonium dicarboxylate particles. In addition, in the present invention, the ammonium dicarboxylate particles that can be contained in the inner and outer layers are the particles defined in the present invention.

[0011] The laminated anticorrosive film for packaging of the present invention may be formed by extrusion molding, or may have a rust inhibitor-containing resin layer formed by other methods. A transparent metal oxide layer may be laminated by vapor deposition or the like, or it may not be laminated at all. However, as the resin component for constituting each layer, for example, using a resin that matches the resin used in the polyolefin resin of the present invention described below may improve adhesion after lamination.

[0012] The thickness of the laminated rust-preventive film for packaging of the present invention is preferably 20 to 150 μm and can be appropriately selected depending on the application. To obtain appropriate rust prevention properties, the total thickness of the inner layer and outer layer of the laminated rust-preventive film for packaging of the present invention is preferably 50% or more, more preferably 80% or more, even more preferably 90% or more, and most preferably 100%. To obtain appropriate rust prevention properties, the ratio of the thickness of the inner layer to the thickness of the outer layer of the laminated rust-preventive film for packaging of the present invention is preferably 20:80 to 80:20, more preferably 30:70 to 70:30, and even more preferably 35:65 to 65:35.

[0013] The inner layer and outer layer, as well as the optional innermost layer, optional intermediate layer, and optional outermost layer, may each independently consist of one layer or two or more layers. When at least one of the optional innermost layer, optional intermediate layer, and optional outermost layer consists of two or more layers, one of the layers may be used as a substrate layer to provide the optional innermost layer, optional intermediate layer, and optional outermost layer for purposes such as imparting strength, gas barrier properties, water vapor barrier properties, and improving tactile feel and aesthetics to the packaging laminate rust-preventive film of the present invention. These innermost layer, intermediate layer, and outermost layer must not impair the effects of the packaging laminate rust-preventive film of the present invention, and are preferably made of materials that have excellent adhesion to the resin that constitutes the packaging laminate rust-preventive film. The substrate layer may be porous or non-porous. The substrate layer may be made of the same resin as the other layers. Such a substrate layer may be formed simultaneously with the formation of the laminated rust-preventive film for packaging, or may be formed separately from the laminated rust-preventive film for packaging and then laminated by known means.

[0014] [Ammonium dicarboxylate particles] The ammonium dicarboxylate particles contained in the laminated rust-preventive film for packaging may be particles of an ammonium aliphatic dicarboxylate and / or an ammonium aromatic dicarboxylate, specifically particles of an ammonium salt of one or more dicarboxylic acids selected from adipic acid, succinic acid, sebacic acid, phthalic acid (ortho-isomer), isophthalic acid, terephthalic acid, oxalic acid, malonic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, undecanedicarboxylic acid, dodecanedioic acid, etc.

[0015] The particle size of the ammonium dicarboxylate particles in the present invention does not refer to the particle size of these particles before being incorporated into the resin, but to the particle size of the particles contained in each layer after being incorporated into the resin to form a laminated rust-preventive film for packaging. The average particle size and maximum particle size of the ammonium dicarboxylate particles are determined by measuring the particle sizes of 2,000 randomly selected particles while visually observing the inner and outer layers of the laminated rust-preventive film for packaging with a microscope, and then calculating the average particle size (sum of the diameters of each particle / 2,000) and maximum particle size based on these results.

[0016] The ammonium dicarboxylate particles of the present invention are obtained by pulverizing and classifying raw ammonium dicarboxylate particles so as to ultimately achieve the specific particle size of the present invention. However, the particle size of the present invention refers to the particle size after mixing and kneading the ammonium dicarboxylate particles with a resin or the like, and molding the mixture into a film by extrusion or other molding under pressure. Therefore, the particle size of the ammonium dicarboxylate particles must be adjusted in anticipation of the fact that the diameter of the ammonium dicarboxylate particles will be reduced due to shear forces, etc., associated with the ammonium dicarboxylate particles during the film formation process. Without the ammonium dicarboxylate particles of the present invention, sufficient rust prevention effect cannot be achieved even with the use of other rust inhibitors, and further, rust inhibitor powder may precipitate on the inner surface of the laminated rust-preventive packaging film and adhere to the surface of the metal product being packaged.

[0017] [A. Ammonium dicarboxylate salt particles contained in at least one of the rust inhibitor-containing resin layer (inner layer) on the inner side facing the contents during packaging and / or the rust inhibitor-containing resin layer (outer layer) on the outer side] In this case A, the ammonium dicarboxylate salt particles may be contained in either or both of the rust inhibitor-containing resin layer on the inner side and the rust inhibitor-containing resin layer on the outer side. The ammonium dicarboxylate salt particles contained in the rust inhibitor-containing resin layer on the inner side facing the contents during packaging and / or the rust inhibitor-containing resin layer on the outer side have a small particle size. In this case, the ammonium dicarboxylate salt particles have an average particle size of 5.0 μm or less and a maximum particle size of 10.0 μm or less. By maintaining the average particle size and maximum particle size within these ranges, rust prevention performance can be achieved for a wider variety of metals. The average particle size is preferably 4.0 μm or less, and the maximum particle size is preferably 9.0 μm or less.

[0018] The average particle size and maximum particle size of the ammonium dicarboxylate salt particles must be smaller than the thickness of the rust inhibitor-containing resin layer on the inner surface side and / or the rust inhibitor-containing resin layer on the outer surface side in which the particles are contained, and the maximum particle size is preferably 70% or less of the thickness of this layer, from the viewpoint of preventing adhesion of the ammonium dicarboxylate salt particle precipitates to the metal product, more preferably 50% or less of the thickness of this layer, even more preferably 40% or less of the thickness of this layer, and most preferably 25% or less of the thickness of this layer. The average particle size of the ammonium dicarboxylate salt particles is preferably 25% or less of the thickness of this layer, from the viewpoint of preventing adhesion of the ammonium dicarboxylate salt particle precipitates to the metal product, more preferably 20% or less of the thickness of this layer, and even more preferably 15% or less of the thickness of this layer. If the average particle size or maximum particle size of the dicarboxylic acid ammonium salt particles contained in the rust inhibitor-containing resin layer on the inner surface side and / or the rust inhibitor-containing resin layer on the outer surface side is too large, the amount of rust inhibitor leaching out may be excessive or the concentration of the rust inhibitor may become too high locally, which may cause rust to form on the packaged item stored in contact with the laminated rust-preventive packaging film.

[0019] [B. Ammonium dicarboxylate salt particles contained in the rust inhibitor-containing resin layer (outer layer) on the outer surface side, not the side facing the contents during packaging] In this case B, the ammonium dicarboxylate salt particles may be contained only in the rust inhibitor-containing resin layer on the outer surface side. In this case, the average particle size of the ammonium dicarboxylate salt particles is more than 5.0 μm and not more than 20.0 μm, and the maximum particle size is more than 10.0 μm and not more than 100.0 μm. The average particle size is preferably not more than 15.0 μm, more preferably not more than 13.0 μm. The maximum particle size is preferably not more than 90.0 μm, more preferably not more than 85.0 μm. If the average particle size or maximum particle size of the ammonium dicarboxylate salt particles contained in the rust inhibitor-containing resin layer on the outer surface side is too large, rust may occur in the packaged item stored in contact with the laminated rust-preventive packaging film.

[0020] The average particle size of the dicarboxylate ammonium salt particles may be smaller than the thickness of the outer surface-side rust inhibitor-containing resin layer containing the particles. To achieve a high rust prevention effect, the average particle size is preferably less than 100% of the thickness of the outer surface-side rust inhibitor-containing resin layer, more preferably 80% or less of the thickness of this layer, even more preferably 60% or less of the thickness of this layer, and most preferably 40% or less of the thickness of this layer. Furthermore, the average particle size of the dicarboxylate ammonium salt particles is preferably smaller than the thickness of the entire laminated rust-preventive packaging film. To achieve a high rust prevention effect, the average particle size is preferably 8% or more of the thickness of this layer, more preferably 10% or more of the thickness of this layer.

[0021] The maximum particle size of the ammonium dicarboxylate particles may be larger than the thickness of the rust inhibitor-containing resin layer on the outer surface in which the particles are contained. To obtain a high rust prevention effect, the maximum particle size is preferably 180% or less of the thickness of this layer, more preferably 150% or less of the thickness of this layer, even more preferably 100% or less of the thickness of this layer, and most preferably 70% or less of the thickness of this layer. Furthermore, the maximum particle size of the ammonium dicarboxylate particles may be larger than, the same as, or smaller than the thickness of the entire laminated rust-preventive packaging film. To obtain a high rust prevention effect, the maximum particle size is preferably 130% or less of the thickness of this layer, more preferably 120% or less of the thickness of this layer, and even more preferably 110% or less of the thickness of this layer.

[0022] In particular, when the laminated rust-preventive film for packaging of the present invention comprises two layers, an inner layer and an outer layer, and is obtained by laminating the two layers, particularly under pressure, the ammonium dicarboxylate salt particles in the outer layer may penetrate into the inner layer and be partially embedded therein. However, the ammonium dicarboxylate salt particles in the outer layer may not penetrate into the inner layer, and some of the particles may protrude outward from the outer layer (away from the inner layer). This configuration allows the inner layer to exhibit stronger spatial and contact rust-preventive functions.

[0023] The content of these dicarboxylic acid ammonium salts is preferably 0.01 parts by weight or more, more preferably 0.05 parts by weight or more, and even more preferably 0.1 parts by weight or more, per 100 parts by weight of the rust inhibitor-containing resin layer. Also, it is preferably 10.0 parts by weight or less, more preferably 9.0 parts by weight or less, and even more preferably 8.0 parts by weight or less. If it is less than 0.01 parts by weight, it may be difficult to achieve long-term rust prevention, and if it exceeds 10.0 parts by weight, molding processing may be difficult.

[0024] [Resin Component of Laminated Rust-Preventive Film for Packaging] The resin component that can be commonly used for the inner and outer layers of the laminated rust-preventive film for packaging of the present invention, as well as the optional innermost, intermediate, and outermost layers, is a polyolefin resin. These polyolefin resins may have the same or different compositions. If the polyolefin resins are the same, it is preferable that when the laminated rust-preventive film for packaging is recycled after use, it can be used as a laminated rust-preventive film for packaging having the same resin composition as before recycling. Constituting each layer with a polyolefin resin is preferable in terms of adhesion when the layers are laminated. There are no particular restrictions on the resin components, as long as they can be formed into a resin composition that can be molded into a film by extrusion molding, especially inflation molding. As such a polyolefin resin, one or more selected from polyolefin-based polymers, i.e., olefin homopolymers and / or copolymers using olefins as monomers, can be selected and used. From the viewpoint of processability, the density of the polyolefin resin should be 0.880 to 0.945 g / cm. ３ From the viewpoint of mechanical strength and processability, the melt flow rate (MFR) is preferably in the range of 1.0 to 10.0 g / 10 min, and by having an appropriate viscosity during melt processing, it becomes possible to prevent the rust inhibitor from falling off from the resin molded product.

[0025] Examples of olefins (olefin monomers) constituting polyolefin polymers include ethylene, propylene, 1-butene, 3-methyl-1-butene, 1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-hexene, and 1-octene. Therefore, examples of polyolefin polymers include ethylene polymers, propylene polymers, 1-butene polymers, 1-hexene polymers, and 4-methyl-1-pentene polymers. These polymers may be used alone or in combination of two or more. In other words, the polyolefin polymer may be a mixture of various polymers.

[0026] Among the above, ethylene-based polymers include ethylene homopolymers (polyethylene) and copolymers of ethylene with other monomers (ethylene copolymers). Examples of ethylene homopolymers and ethylene copolymers include low-density polyethylene (LDPE), linear low-density polyethylene (L-LDPE), medium-density polyethylene (MDPE), and high-density polyethylene (HDPE). Among the low-density polyethylenes and / or linear low-density polyethylenes, those with a density of 0.925 g / cm ３ The following is preferred: 0.924 g / cm ３ The following is more preferred: 0.923 g / cm ３ The following is more preferred: Density 0.925 g / cm ３ When the density is less than or equal to this, moldability is particularly improved, and once the film-like material is obtained, processing such as heat sealing can be easily performed. Furthermore, polyethylene having such a density range preferably accounts for 50% by weight or more of the resin component of the polyolefin resin layer in the present invention. Examples of ethylene copolymers include ethylene-propylene copolymers, ethylene-1-butene copolymers, ethylene-1-pentene copolymers, ethylene-1-hexene copolymers, ethylene-1-octene copolymers, and ethylene-4-methyl-1-pentene copolymers. The ethylene units (structural units derived from ethylene) contained in the ethylene copolymer need only account for more than 50% of the total number of structural units (usually 99.999% or less). For example, the ethylene units may account for 80.0 to 99.999%, 90.0 to 99.995%, or even 99.0 to 99.990% of the total number of structural units.

[0027] Examples of propylene-based polymers include propylene homopolymers (polypropylene) and copolymers of propylene with other monomers (propylene copolymers). Examples of propylene copolymers include propylene-ethylene copolymers, propylene-1-butene copolymers, propylene-1-pentene copolymers, and propylene-1-octene copolymers. The propylene units (structural units derived from propylene) contained in the propylene copolymers may account for 50% or more (usually 99.999% or less) of the total number of structural units, but may account for, for example, 80.0 to 99.999%, 90.0 to 99.995%, or even 99.0 to 99.990% of the total number of structural units.

[0028] Furthermore, the polyolefin polymer may contain structural units derived from monomers other than olefins, provided that the objectives of the present invention are not impaired. Examples of monomers other than olefins include unsaturated carboxylic acids (acrylic acid, methacrylic acid, maleic acid, fumaric acid, etc.), unsaturated carboxylic acid esters (methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dimethyl maleate, diethyl maleate, etc.), and vinyl esters (vinyl acetate, vinyl propionate, maleic acid monoester, etc.). These may be used alone or in combination of two or more. Furthermore, structural units derived from monomers other than olefins contained in the polyolefin polymer, if any, preferably account for 40% or less (usually 0.001% or more) of the total number of structural units. For example, the structural units may be 0.001 to 25%, 0.005 to 15%, or even 0.01 to 10% of the total number of structural units.

[0029] [Other Resins That May Be Used in Each Layer Constituting the Laminated Anti-corrosive Film for Packaging of the Present Invention] In addition to the polyolefin resin that is essential for the polyolefin resin layer, other resins may be used in combination with the polyolefin resin layer. Alternatively, no other resins may be used in combination. Resins other than polyolefin resins may be blended within a range that does not impair the effects of the present invention. Alternatively, no other resins may be blended. For example, when the essential polyolefin resin is a polyethylene resin, the polyethylene resin can be arbitrarily selected from those listed above, and resins that can be used in combination with the polyethylene resin can be selected from those other than polyethylene resin.

[0030] [Other Rust Inhibitors That May Be Included in the Resin Constituting the Laminated Rust-Preventive Film for Packaging of the Present Invention] In addition to the ammonium dicarboxylate salt particles of the present invention, examples of rust inhibitors that may be included in one or more resin layers that can be used in common in the inner layer, outer layer, and optionally the outermost layer constituting the laminated rust-preventive film for packaging include the following amine salts and / or ammonium salts of organic acids and / or inorganic acids, and the following other rust inhibitors. It is particularly preferred that the following rust inhibitors be included in the inner layer and outer layer.

[0031] [Amine salts and / or ammonium salts of organic acids and / or inorganic acids (salts other than ammonium dicarboxylate salts)] (Amine / ammonium salts) Examples of amine / ammonium salts include the following amine / ammonium salts of monocarboxylic acids, amine / ammonium salts of carbonic acid and nitrous acid, etc., which are used as rust inhibitors. These amine salts and ammonium salts may or may not be contained within a range that does not impair the effects of the present invention.

[0032] (Ammonium Carboxylate Salt) The ammonium carboxylate may be either an aliphatic monocarboxylic acid ammonium salt or an aromatic monocarboxylic acid ammonium salt. Specific examples of the ammonium carboxylate include ammonium salts of aliphatic carboxylic acids such as butyric acid, isobutyric acid, methacrylic acid, valeric acid, caproic acid, caprylic acid, capric acid, lauric acid, tridecylic acid, myristic acid, palmitic acid, stearic acid, sorbic acid, oleic acid, oleic acid, isohexanoic acid, 2-methylpentanoic acid, 2-ethylbutanoic acid, isoheptanoic acid, isooctanoic acid, 2-ethylhexanoic acid, isononanoic acid, isodecanoic acid, 2-propylheptanoic acid, isoundecanoic acid, isododecanoic acid, and 2-butyloctanoic acid, as well as ammonium salts of aromatic carboxylic acids such as benzoic acid, aminobenzoic acid, salicylic acid, p-tert-butylbenzoic acid, o-sulfobenzoic acid, 1-naphthoic acid, 2-naphthoic acid, and cinnamic acid.

[0033] (Amine Carboxylate Salt) As the amine carboxylate, a salt can be selected which is obtained by combining the same carboxylic acid as the carboxylic acid component constituting the ammonium carboxylate with diisopropylamine, mono-, di-, or triethanolamine, n-, di-, or tert-butylamine, hexamethylenediamine, hexamethylenetetramine, mono- or dicyclohexylamine, isopropylamine, oleylamine, naphthylamine, or diphenylamine as a salt.

[0034] (Amine salts / ammonium salts of carbonic acid or nitrous acid) In the above-mentioned ammonium carboxylates and amine salts of carboxylic acids, those in which the carboxylic acid is replaced with carbonic acid or nitrous acid can be used. Among these, cyclohexylamine carbonate (CHC) is preferred.

[0035] [Other Rust Inhibitors] The following rust inhibitors may be used in any layer of the laminated rust-preventive film for packaging of the present invention, or may not be used in combination, as long as the effects of the present invention are not impaired.

[0036] (Azole Compound) The azole compound contained in any layer of the laminated rust-preventive film for packaging of the present invention may be a benzotriazole-based compound and / or a tolyltriazole-based compound. Among these, one or more compounds selected from benzotriazole (BTA), 4-methylbenzotriazole, 5-methylbenzotriazole (TTA), carboxybenzotriazole, 3-methyl-5-hydroxybenzotriazole, etc. may be used. When an azole compound is contained in the rust inhibitor-containing resin layer of the present invention, the content of the azole compound is preferably 0.001 parts by weight or more, more preferably 0.01 parts by weight or more, and even more preferably 0.05 parts by weight or more, per 100 parts by weight of the rust inhibitor-containing resin layer. The content is preferably 10.0 parts by weight or less, more preferably 3.0 parts by weight or less, even more preferably 1.0 part by weight or less, and most preferably 0.50 parts by weight or less. Less than 0.001 parts by weight may make it difficult to further improve long-term rust prevention, while more than 10.0 parts by weight may make molding difficult. When an azole compound is contained, it is preferably contained in the inner layer.

[0037] (Metal Nitrite) The metal forming the metal nitrite may be either an alkali metal or an alkaline earth metal. Of these, sodium, potassium, and magnesium are preferred. The metal nitrite may be metal nitrite particles having an average particle size of 50 μm or more. The metal nitrite may be contained within a range that does not impair the effects of the present invention, but it is not necessary to contain it.

[0038] (Carboxylic Acid Metal Salt) Any layer of the laminated rust-preventive film for packaging of the present invention may or may not contain a carboxylate metal salt, as long as the effect of the present invention is not impaired. The carboxylate metal salt may be either an aliphatic carboxylate metal salt or an aromatic carboxylate metal salt. Examples of these carboxylate metal salts include isobutyric acid, methacrylic acid, valeric acid, caproic acid, caprylic acid, capric acid, lauric acid, tridecylic acid, stearic acid, myristic acid, palmitic acid, sorbic acid, oleic acid, oleic acid, isohexanoic acid, 2-methylpentanoic acid, 2-ethylbutanoic acid, isoheptanoic acid, isooctanoic acid, 2-ethylhexanoic acid, isononanoic acid, isodecanoic acid, 2-propylheptanoic acid, isoundecanoic acid, isododecanoic acid, 2-butyloctanoic acid, sucralose ... One or more metal salts, such as sodium salts, potassium salts, calcium salts, and magnesium salts, of aliphatic carboxylic acids such as benzoic acid, aminobenzoic acid, salicylic acid, p-tert-butylbenzoic acid, o-sulfobenzoic acid, 1-naphthoic acid, 2-naphthoic acid, phthalic acid, isophthalic acid, terephthalic acid, and cinnamic acid can be used. Among these metal carboxylic acid salts, it is preferable to incorporate aliphatic monocarboxylic acid metal salts, particularly sodium salts of aliphatic monocarboxylic acids having 6 to 18 carbon atoms, or aliphatic dicarboxylic acid metal salts, particularly sodium salts of aliphatic dicarboxylic acids having 6 to 18 carbon atoms, into the inner and / or outer layers in order to improve rust prevention. It is particularly preferable to incorporate aliphatic monocarboxylic acid metal salts into the inner and outer layers. It is also preferable that the outer layer contains a metal salt of an aliphatic dicarboxylic acid.

[0039] These metal carboxylates may also be substituted with a hydroxyl group or an amino group. When a metal carboxylate is incorporated into the rust inhibitor-containing resin layer of the present invention, the content of the metal carboxylate is preferably 0.001 parts by weight or more, more preferably 0.01 parts by weight or more, and even more preferably 0.05 parts by weight or more, per 100 parts by weight of the rust inhibitor-containing resin layer. Also, the content is preferably 10.0 parts by weight or less, more preferably 3.0 parts by weight or less, even more preferably 1.0 parts by weight or less, and most preferably 0.50 parts by weight or less. If the content is less than 0.001 parts by weight, it may be difficult to further improve long-term rust prevention, and if it exceeds 10.0 parts by weight, molding may be difficult. When an aliphatic dicarboxylic acid metal salt is incorporated, it is preferable to incorporate it into both the inner layer and the outer layer in order to exhibit excellent rust prevention properties.

[0040] (Urea Compound) A urea compound selected from urea, methylurea, ethylurea, propylurea, thiourea, and urotropine may or may not be contained within a range that does not impair the effects of the present invention.

[0041] (Other Heterocyclic Compounds) Heterocyclic compounds selected from 3-methyl-5-hydroxypyrazole, 5-amino-1H-tetrazole, imidazole, 2-methylimidazole, 5-methylimidazole, benzimidazole, mercaptobenzothiazole, etc. may or may not be contained within a range that does not impair the effects of the present invention.

[0042] (Porous Silica Particles) Any layer of the laminated rust-preventive film for packaging of the present invention may or may not contain porous silica particles, provided that the effects of the present invention are not impaired. The average particle size of the porous silica particles measured by a laser method (average particle size determined by dynamic image analysis (ISO 13322-2) using a Microtrac CAMSIZER X2) is preferably 1.0 μm or more, more preferably 2.0 μm or more, and even more preferably 3.0 μm or more. It is also preferably 20.0 μm or less, more preferably 10.0 μm or less, and even more preferably 5.0 μm or less. The oil absorption of the porous silica particles is preferably 100 ml / 100 g or more, more preferably 130 ml / 100 g or more, and even more preferably 150 ml / 100 g or more. It is also preferably 400 ml / 100 g or less, more preferably 300 ml / 100 g or less, and even more preferably 250 ml / 100 g or less.

[0043] Furthermore, the content of porous silica particles in any layer of the laminated rust-preventive film for packaging in the present invention is preferably 0.01 parts by weight or more, more preferably 0.03 parts by weight or more, and even more preferably 0.05 parts by weight or more, relative to 100 parts by weight of resin. And, relative to 100 parts by weight of resin, it is preferably 0.30 parts by weight or less, more preferably 0.20 parts by weight or less, and even more preferably 0.10 parts by weight or less. The content of porous silica particles relative to 100 parts by weight of the azole compound contained in the rust inhibitor-containing resin layer in the present invention is preferably 20 parts by weight or more, more preferably 40 parts by weight or more, and even more preferably 50 parts by weight or more. And, relative to 100 parts by weight of the azole compound, it is preferably 300 parts by weight or less, more preferably 200 parts by weight or less, and even more preferably 150 parts by weight or less. The content of porous silica particles relative to the content of the azole compound may be such that the azole compound is properly supported and released over a long period of time, thereby exhibiting a rust-preventive effect.

[0044] (Inorganic Acid Metal Salt) Any layer of the laminated rust-preventive film for packaging according to the present invention may or may not independently contain an inorganic acid metal salt. Among these, one or more selected from metal borosilicates, borates, metaborates, metal molybdates, polyphosphates, and the like can be used. Among inorganic acid metal salts, sodium borosilicate is preferred. When an inorganic acid metal salt is contained in the rust inhibitor-containing resin layer of the present invention, the content of the inorganic acid metal salt is preferably 0.001 parts by weight or more, more preferably 0.01 parts by weight or more, and even more preferably 0.05 parts by weight or more, per 100 parts by weight of the rust inhibitor-containing resin layer. Furthermore, the content is preferably 10.0 parts by weight or less, more preferably 3.0 parts by weight or less, even more preferably 1.0 parts by weight or less, and most preferably 0.50 parts by weight or less. Less than 0.001 parts by weight may make it difficult to further improve long-term rust prevention, while more than 10.0 parts by weight may make molding difficult. When an inorganic acid metal salt is contained, it is preferable to contain it in the inner layer in order to exhibit excellent rust prevention properties.

[0045] In the case of the laminated rust-preventive film for packaging of the present invention, in the case of A above, one or both of the inner and outer layers contain ammonium dicarboxylate salt particles having an average particle size of 5.0 μm or less and a maximum particle size of 10.0 μm or less. Furthermore, when the specific ammonium dicarboxylate salt particles are contained in only one of the inner and outer layers, the following composition of the inner or outer layer is preferred. Regardless of whether the outer layer contains specific ammonium dicarboxylate salt particles, when the inner layer contains specific ammonium dicarboxylate salt particles, it is preferred that the outer layer contain a metal salt such as a sodium salt of an aliphatic carboxylic acid. Regardless of whether the inner layer contains specific ammonium dicarboxylate salt particles, when the outer layer contains specific ammonium dicarboxylate salt particles, it is preferred that the inner layer contain one or more compounds selected from metal salts such as sodium salts of aliphatic carboxylic acids and inorganic acids, benzotriazole-based compounds, and tolyltriazole-based compounds. Furthermore, in the case of B above, the inner and / or outer layer do not contain the ammonium dicarboxylate salt particles defined in A above. The inner layer does not contain ammonium dicarboxylate particles having an average particle size of more than 5.0 μm and not more than 20.0 μm and a maximum particle size of more than 10.0 μm and not more than 100.0 μm.

[0046] Furthermore, to the extent that the effects of the present invention are not impaired, each resin layer may independently contain known additives other than those described above, such as antiblocking agents (AB agents), lubricants, antioxidants, antistatic agents, UV absorbers, light stabilizers, oxygen absorbers, acid absorbers, nucleating agents, impact strength enhancers, plasticizers, release agents, colorants, fluorescent agents, compatibilizers, antifogging agents, fillers, auxiliary colorants, dispersants, stabilizers, modifiers, and antibacterial and antifungal agents. However, it is necessary that these additives do not react with other components contained in the inner layer, outer layer, etc., and do not bleed out, for example, to contaminate the packaged product. Furthermore, ionomer resins or functional group-containing polyolefin resins may or may not be blended into each resin layer in order to retain the rust inhibitor in the resin layer. This allows for sufficient long-term rust prevention.

[0047] (Production and Use of Laminated Rust-Preventive Film for Packaging) The laminated rust-preventive film for packaging of the present invention and each of the layers constituting the laminated rust-preventive film for packaging are formed by known methods such as extrusion molding, inflation molding, vacuum molding, and pressure molding, and laminated by any means as needed. Among these, inflation molding is preferred. The obtained laminated rust-preventive film for packaging can be used to form films, sheets, bags, laminated sheets, and containers of any shape, such as cylindrical or box-like containers. The laminated rust-preventive film for packaging may also be laminated with other rust-preventive agent-containing resin layers or substrate films. The laminated rust-preventive film for packaging of the present invention is used such that the inner layer is positioned on the side of the article to be stored or packaged and rust-prevented. By placing this layer of specific composition on the inner side, sufficient rust prevention properties can be provided and the effect of preventing deposits of the rust inhibitor from adhering to the surface of the packaged metal article can be achieved.

[0048] According to the laminated rust-preventive film for packaging, moisture gradually penetrates from the outside air in contact with the outer surface of the laminated rust-preventive film toward the interior, and the amount of rust-preventive gas generated is also gradually reduced. Therefore, a high rust-preventive effect can be maintained stably for a long period of time, even without the addition of a rust-preventive sustained-release agent such as a carboxylic acid-modified polyolefin polymer, waxes, nonionic surfactants, or inorganic porous bodies. It is also possible to add a rust-preventive sustained-release agent such as a carboxylic acid-modified polyolefin polymer, waxes, nonionic surfactants, or inorganic porous bodies. Furthermore, a wide range of items, such as cast iron, can be targeted for rust prevention.

[0049] The present invention will be described in more detail with reference to the following examples and comparative examples. Note that the examples show one embodiment of the present invention, and the present invention is not limited thereto.

[0050] Each component was hand-blended and stirred to prepare molding compounds for the inner and outer layers, respectively, to obtain the compositions shown in Tables 1 and 2 for each Example and Comparative Example. Using these compounds, tubular laminated films were produced using an inflation extrusion molding machine. TTA in Table 2 stands for 5-methylbenzotriazole. The total thickness of the laminated films in all Examples and Comparative Examples was 80 μm. The results for these laminated films are shown in Tables 1 and 2. Molding conditions: Molding temperature 140°C, Molding speed: 18 kg / min, Pressurizing pressure: 12 MPa. Filter: Two filters with mesh #40 (JIS standard) stacked on top of each other were used. LDPE: F200 (Sumitomo Chemical Co., Ltd.) (low-density polyethylene, MFR 2.0 g / 10 min, density 0.924 g / cm ３ , melting point 111°C)

[0051] [Rust prevention performance (space test)] The following test specimens were hung with nylon fishing line in a frame measuring 100 mm long x 100 mm wide x 150 mm high, and the entire surface of the frame was gusset-sealed with a laminated rust prevention film for packaging. Note that "space Fc" indicates a test in which Fc250 was not in contact with the laminated rust prevention film for packaging. [Rust prevention performance (contact test)] Two sheets of rust prevention film measuring 80 mm long x 60 mm wide were heat-sealed around the periphery, and the following test specimens were inserted inside to form a bag-like object, which was then hung in a space under the test environment. Note that "contact Fc, contact SGCC, contact Al" indicate tests in which the test specimens were in contact with the laminated rust prevention film for packaging. <A. Test piece> Fc: Fc250 (cast iron) (JIS G 5501) Size: φ30 mm x 8 mm SGCC: Hot-dip galvanized steel plate (JIS H 8610) Size: 1.4 mm x 30 mm x 50 mm Al: Aluminum plate (JIS H 4000) Size: 1.2 mm x 30 mm x 50 mm

[0052] <B. Test environment> (Space test) First, the sample was placed in an environment of 25°C and 70% RH for 4 hours, followed by a set transfer time of 2 hours, and then placed in an environment of 50°C and 95% RH for 4 hours, followed by a set transfer time of 2 hours. This constituted one cycle. This was repeated 28 times in succession, making the test period 14 days. (Contact test) The sample was placed in a constant environment of 50°C and 95% RH. The test period was 30 days. <C. Evaluation criteria> ◯: No rust or discoloration ×: Rust spots or slight discoloration

[0053] [Presence or absence of precipitated powder] The laminated anticorrosive film for packaging was stored in the test environment of the above-mentioned spatial test for a test period of 3 days, and the film after storage was visually observed. <Evaluation criteria for the presence or absence of precipitated powder> ◯: No precipitated powder was observed ×: Precipitated powder was observed

[0054]

[0055]

[0056] In Examples 1 to 22, which are examples in accordance with the present invention, no precipitated powder was generated after storage, and rust prevention was reliably achieved for each metal material. The stored metal materials not only eliminated the need for laborious rust removal from rusted areas, but also allowed for processing, assembly, and other processes without requiring special treatment, such as removing precipitated powder. Example 21, which also used the ammonium dicarboxylate salt used in Comparative Examples 10 and 11, and Example 22, which also used the ammonium dicarboxylate salt used in Comparative Examples 8 and 10, achieved similar results to the other Examples. In contrast, in Comparative Examples 1 to 3, which did not contain an ammonium dicarboxylate salt in the inner or outer layer, the generation of precipitated powder was confirmed after storage. Comparative Examples 4 and 5 are examples in which ammonium dicarboxylate salt particles, which may be contained only in the outer layer (exterior surface side), were contained in the inner layer. Comparative Examples 6 and 7 are examples in which the ammonium dicarboxylate salt particles contained in the outer layer were larger than the average and maximum particle sizes that may be contained. Comparative Example 8 is an example in which the average particle size of the ammonium dicarboxylate salt particles contained in the outer layer is smaller than the allowable average particle size, and Comparative Example 9 is an example in which the maximum particle size of the ammonium dicarboxylate salt particles contained in the outer layer is larger than the allowable maximum particle size. Comparative Example 10 is an example in which the maximum particle size of the ammonium dicarboxylate salt particles contained in the outer layer is smaller than the allowable maximum particle size, and Comparative Example 11 is an example in which the average particle size of the ammonium dicarboxylate salt particles contained in the outer layer is smaller than the allowable average particle size. Although no precipitated powder was generated in these Comparative Examples, rust was generated on the hot-dip galvanized steel sheet (SGCC) in contact with the inner layer surface in Comparative Examples 4, 6, 8, and 9, and rust was generated on the cast iron (Fc250) and aluminum sheet (Al) in contact with the inner layer surface in Comparative Examples 5, 7, 10, and 11.

Claims

1. A laminated anti-rust film for packaging that has a rust inhibitor-containing resin layer on the inner side facing the contents during packaging and a rust inhibitor-containing resin layer on the outer side, and that satisfies A or B below. A. The rust inhibitor-containing resin layer on the inner surface side and / or the rust inhibitor-containing resin layer on the outer surface side contain ammonium dicarboxylate particles having an average particle size of 5.0 μm or less and a maximum particle size of 10.0 μm or less. B. Only the outer surface side rust inhibitor-containing resin layer contains ammonium dicarboxylate particles having an average particle size of more than 5.0 μm and not more than 20.0 μm and a maximum particle size of more than 10.0 μm and not more than 100.0 μm.

2. The laminated anticorrosive film for packaging according to claim 1, wherein the ammonium dicarboxylate is at least one selected from the group consisting of ammonium adipate, ammonium succinate, ammonium sebacate, ammonium phthalate, ammonium isophthalate, and ammonium terephthalate.

3. A laminated anti-rust film for packaging as described in claim 1 or 2, wherein the anti-rust agent-containing resin layer on the inner surface side contains one or more compounds selected from aliphatic carboxylic acid metal salts, inorganic acid metal salts, benzotriazole-based compounds, and tolyltriazole-based compounds.

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