Anti-rust film

Abstract

The present invention addresses the problem of improving anti-corrosion effects by efficiently releasing a large amount of a corrosion inhibitor even if a large amount of the corrosion inhibitor is not included in a resin. As a solution to this problem, provided is an anti-corrosion film that includes items (A)-(C). (A) a polyolefin resin, (B) 0.05-1.00 wt%, with respect to the anti-corrosion film, of a carboxylic acid alkali metal salt having an average particle diameter of 100 μm or less and a solubility in water at 50°C of 0.1 wt% or more, and (C) 0.05-5.00 wt%, with respect to the anti-corrosion film, of particles having an average particle diameter of 5.0-200 μm, an aspect ratio of 1.0-20.0, and a specific surface area of 100 m2 / g or less.

Description

[Technical Field]

[0001] The present invention relates to an anti-corrosion film. [Background technology]

[0002] When using rust inhibitors as materials for packaging metal products, one method for achieving long-term effects from the rust inhibitor is to disperse and support them in a resin. For ease of processing, non-polar polyolefin resins, such as low-density polyethylene, are often selected as the resin. However, since these resins and rust inhibitors are generally not compatible with each other, it has been difficult to control the release of the rust inhibitor. It has also been difficult to release a large amount of the rust inhibitor. Therefore, if a large amount of rust inhibitor is added to the resin in order to release more of the rust inhibitor, the rust inhibitor will precipitate on the product surface relatively soon after production, a phenomenon known as bleed-out or bloom-out, which could degrade the product's appearance and impair its value.

[0003] For example, when a metal product is coated with the anti-rust film described in Patent Document 1, the volatile anti-rust agent released from the anti-rust film is present in the space formed between the metal product and the anti-rust film, thereby preventing rust on the surface of the metal product facing that space. However, the metal surface in the area where the anti-rust film is in close contact with the metal product is not exposed to the air containing the volatile anti-rust agent, so there is a risk that sufficient rust prevention will not be achieved. For this reason, the anti-rust film has sometimes been used in combination with a desiccant or with other anti-rust ingredients. Furthermore, it has been necessary to preliminarily incorporate a relatively large amount of anti-rust agent into the anti-rust film so that the anti-rust effect does not decrease during the period in which the metal product is packaged. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-44014 [Patent Document 2] Japanese Patent Application Publication No. 2019-131267 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to improve the rust prevention effect by efficiently releasing a large amount of rust inhibitor without incorporating a large amount of rust inhibitor into a resin. [Means for solving the problem]

[0006] As a result of extensive research into solving the above problems, the present inventors have found that the problems can be solved by the following means, and have thus achieved the present invention. 1. A rust-preventive film containing the following (A) to (C): (A) Polyolefin resin (B) 0.05 to 1.00% by weight of an alkali metal carboxylate having an average particle size of 100 μm or less and a solubility in water at 50° C. of 0.1% by weight or more relative to the rust-preventive film. (C) An average particle size of 5.0 to 200 μm, an aspect ratio of 1.0 to 20.0, and a specific surface area of ​​100 m 2 / g or less particles, 0.05 to 5.00% by weight of the anti-corrosion film 2. The rust-preventive film according to 1, wherein the carboxylic acid of the alkali metal carboxylic acid salt is an aliphatic carboxylic acid and / or an aromatic carboxylic acid. 3. The rust-preventive film according to 1 or 2, wherein the carboxylic acid of the alkali metal carboxylic acid salt is one or more selected from the group consisting of saturated C8 to C16 monocarboxylic acids, saturated C8 to C16 dicarboxylic acids, unsaturated C8 to C22 monocarboxylic acids, and unsaturated C8 to C22 dicarboxylic acids. 4. The anticorrosive film according to any one of 1 to 3, wherein the particles are inorganic particles and / or resin particles. 5. An anticorrosive film having an anticorrosive layer containing the following (A) to (C) and (D) a substrate layer: (A) Polyolefin resin (B) 0.05 to 1.00% by weight of an alkali metal carboxylate having an average particle size of 100 μm or less and a solubility in water at 50° C. of 0.1% by weight or more relative to the rust-preventive layer. (C) An average particle size of 5.0 to 200 μm, an aspect ratio of 1.0 to 20.0, and a specific surface area of ​​100 m 2 / g or less particles, 0.05 to 5.00% by weight of the anti-corrosion layer 6. The rust-preventive film according to 5, wherein the carboxylic acid of the alkali metal carboxylic acid salt is an aliphatic carboxylic acid and / or an aromatic carboxylic acid. 7. The rust-preventive film according to 5 or 6, wherein the carboxylic acid of the alkali metal carboxylic acid salt is one or more selected from the group consisting of saturated C8 to C16 monocarboxylic acids, saturated C8 to C16 dicarboxylic acids, unsaturated C8 to C22 monocarboxylic acids, and unsaturated C8 to C22 dicarboxylic acids. 8. The anticorrosive film according to any one of 5 to 7, wherein the particles are inorganic particles and / or resin particles. [Effects of the Invention]

[0007] According to the present invention, even if a large amount of rust inhibitor is not contained in the resin, the rust prevention effect can be improved by releasing a larger amount of rust inhibitor. DETAILED DESCRIPTION OF THE INVENTION

[0008] The present invention is a rust-preventive film that basically contains a polyolefin resin, a specific rust inhibitor, and further specific particles. The anti-rust film of the present invention can be made to any thickness, but by using component (C) in the present invention in combination, it can be made to a thickness of 50 μm or more, which is the thickness of conventional anti-rust films, and can also be made to an even thinner film of 20 to 50 μm. By making the film thinner, the amount of anti-rust agent used per unit area of ​​the anti-rust film can be reduced.

[0009] (A) Polyolefin resin In the present invention, the polyolefin resin of the component (A) is used for containers, packaging films, and the like. Specific examples include α-olefin homopolymers such as polyethylene and polypropylene (PP); copolymers of ethylene and C3-C8 α-olefins such as ethylene-propylene copolymer, ethylene-butene-1 copolymer, ethylene-4-methyl-1-pentene copolymer, and ethylene-hexene copolymer; ethylene-cyclic olefin copolymers obtained by copolymerizing ethylene with cyclic olefins such as cyclopentadiene and norbornene; copolymers of ethylene and a carboxylic acid derivative having an ethylenically unsaturated bond, such as ethylene-vinyl acetate copolymer (EVA), ethylene-acrylic acid copolymer, and ethylene-vinyl acetate-methyl methacrylate copolymer; and blends thereof.

[0010] Among the above polyolefin resins, when the resin is to be used as a packaging material, for example, polyethylene is appropriate to select from the viewpoints of product cost and ease of production. Various types of polyethylene, such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and high-density polyethylene (HDPE), can be selected in consideration of their properties. The preferred density of polyolefin resin is 0.880 to 0.960 g / cm 3 and 0.890 g / cm 3 More preferably, 0.900 g / cm 3 More preferably, the density is 0.950 g / cm or more. 3 Less than 0.930 g / cm is more preferable. 3 The following is even more preferred: The MFR of the polyolefin resin is preferably 0.1 to 30.0 g / 10 min, more preferably 0.5 g / 10 min or more, even more preferably 1.0 g / 10 min or more, and most preferably 1.5 g / 10 min or more, and more preferably 20.0 g / 10 min or less, even more preferably 10.0 g / 10 min or less, and most preferably 6.0 g / 10 min or less. By using a polyolefin resin within the above range, the film can be suitably used as a rust-preventive film for packaging various metal products of various shapes and weights.

[0011] (B) Alkali metal carboxylate The alkali metal carboxylate salt contained in the polyolefin resin (A) as the rust inhibitor and having a solubility in water at 50°C of 0.1 wt% or more has an average particle size of 100 μm or less, preferably 70 μm or less, more preferably 40 μm or less, even more preferably 20 μm or less, and most preferably 15 μm or less. The average particle size is preferably 0.1 μm or more, more preferably 0.5 μm or more, even more preferably 1.0 μm or more, and most preferably 1.5 μm or more. A larger average particle size, assuming a given content concentration, can lead to a decrease in the mechanical strength of a film containing the rust inhibitor, a tendency for concentration unevenness to occur, and ultimately a decrease in rust prevention ability. On the other hand, if the average particle size is less than 0.1 μm, the alkali metal carboxylate salt particles are more likely to aggregate, making it difficult to uniformly disperse them in the polyolefin resin during film production. One or more alkali metal carboxylates can be selected and used. If the solubility of an alkali metal carboxylate in water at 50° C. is less than 0.1% by weight, it will not be able to exhibit a sufficient rust-preventing effect even if it satisfies the other requirements of the present invention. This rust inhibitor is a water-soluble rust inhibitor with a solubility of 0.1% by weight or more in water at 50°C, so when it is contained in a non-polar polyolefin resin, it is dispersed in the resin in the form of particles. Here, the average particle diameters of the major axis and the minor axis are measured by image analysis using a CAMSIZER X2 manufactured by Microtrac. In the present invention, the average particle size of the alkali metal carboxylate indicates the major axis D50.

[0012] As the alkali metal carboxylate, an alkali metal aliphatic carboxylate and / or an alkali metal aromatic carboxylate can be used. The alkali metal salt of an aliphatic carboxylic acid may be either a saturated or unsaturated alkali metal salt of an aliphatic carboxylic acid, and examples thereof include alkali metal salts of phthalic acid, p-tert-butylbenzoic acid, p-nitrobenzoic acid, benzoic acid, lauric acid, decanoic acid, nonanoic acid, octanoic acid, heptanoic acid, hexanoic acid, caprylic acid, sebacic acid, adipic acid, oleic acid, myristic acid, palmitic acid, succinic acid, citric acid, and tartaric acid. The alkali metal salts of saturated monocarboxylic acids and saturated dicarboxylic acids are preferably those of C8 to C16, more preferably those of C8 to C14, and even more preferably those of C8 to C12. The alkali metal salts of unsaturated monocarboxylic acids and alkali metal salts of unsaturated dicarboxylic acids are preferably those having C8 to C22, more preferably those having C12 to C20, and even more preferably those having C14 to C18. Among these rust inhibitors, it is preferable to employ sodium laurate, potassium laurate, sodium caprylate, potassium caprylate, sodium sebacate, potassium sebacate, sodium oleate, potassium oleate, sodium p-tert-butylbenzoate, sodium p-nitrobenzoate, sodium myristate, potassium myristate, sodium palmitate, potassium palmitate, sodium succinate, potassium succinate, sodium citrate, potassium citrate, sodium adipate, potassium adipate, and sodium tartrate. As the rust inhibitor, sodium benzoate, which has a relatively high volatility, may or may not be used. In addition to these alkali metal carboxylic acid salts, the composition may contain, but does not necessarily contain, acids other than carboxylic acids or salts thereof, such as free carboxylic acids such as benzoic acid and nitrobenzoic acid, and alkali metal salts and alkaline earth metal salts of nitrous acid.

[0013] The appropriate amount of (B) rust inhibitor to be added varies depending on the metal product to be rust-prevented and the desired rust-preventing effect, but generally, if the amount is too small, the rust-preventing ingredients will not be dispersed over a wide area and sufficient rust-preventing effect will not be obtained. Conversely, if the amount is too large, it may have a negative effect on the physical strength of the rust-preventing film, and sufficient rust-preventing effect may not be obtained. Therefore, to obtain a stable effect, the content of the anticorrosive film is 0.05 to 1.00% by weight. From the viewpoint of manufacturing, the content is preferably 0.08% by weight or more, more preferably 0.10% by weight or more. The content is preferably 0.80% by weight or less, more preferably 0.60% by weight or less, and even more preferably 0.50% by weight or less. The rust inhibitor (B) in the present invention is not a volatile rust inhibitor, and therefore does not vaporize to cause the vaporized rust inhibitor to exist in the space packaged with the rust-preventive film. By wrapping the material to be rust-prevented in the rust-preventive film or by laying the rust-preventive film underneath the material to be rust-prevented, the rust inhibitor on the surface of the rust-preventive film comes into direct contact with the contact point of the material to be rust-prevented with the rust-preventive film, thereby preventing rust at the contact point. Therefore, it is not necessary to add a volatile rust inhibitor such as sodium benzoate.

[0014] Furthermore, if necessary, it is possible to further improve the rust prevention effect by adding salts of alkali metals or alkaline earth metals of inorganic acids such as nitrous acid, carbonic acid, phosphoric acid, boric acid, and silicic acid, which do not have volatility. Furthermore, it is not necessary to compound volatile rust inhibitors such as organic acid amides, ammonium nitrate, ammonium borate, inorganic amine salts, amine salts of carboxylic acids, triazole-based rust inhibitors, and the like. These rust inhibitors provide rust prevention properties by blending them in the required amount, regardless of whether particles (C) are present or not.

[0015] (C) Particle The particles blended in the present invention must maintain their particle shape during processing, such as in the olefin resin and under heat-melting conditions. The particle surface may be either hydrophilic or hydrophobic, but if it is hydrophilic, the rust inhibitor can be released more quickly. Within the rust-preventive film of the present invention, the rust inhibitor can migrate along the particle surface, resulting in a larger amount of rust inhibitor being migrated to the surface of the rust-preventive film more quickly. Furthermore, the film may or may not contain fibrous materials such as cellulose fibers. As a means for making the particle surfaces hydrophobic, a means can be employed in which silanol groups of silica or the like on the surface are treated with a surface treatment agent such as polydimethylsiloxane, methylchlorosilane, or hexamethyldisilazane.

[0016] Such particles may be any water-insoluble inorganic particles or resin particles that are not rust inhibitors. Particles made of known resins such as glass beads, silica, alumina, calcium carbonate, polymethyl methacrylate (PMMA) particles, (meth)acrylic resins, polyester resins, polyamide resins, polyurethane resins, and silicone resins can be used. Among these, silica and calcium carbonate are preferred. The particle surfaces may be porous, but they do not have to be. It is not necessary to use particles that themselves have free acid groups or are reactive with or water-soluble, such as particles of alkali metal or alkaline earth metal hydroxides, oxidizable metal powders, silicates, or nitrobenzoic acid.

[0017] Even if the particles are porous, the upper limit of their specific surface area is 100 m 2 / g. The specific surface area of ​​the particles is 80m 2 / g or less is preferable, and 50m 2 / g or less is more preferable, and 30m 2 / g or less is more preferable, and 20m 2 / g or less is most preferable. The larger the specific surface area of ​​the particles, the more microscopic pores there are on the particle surface, and the more easily the rust inhibitor penetrates, is adsorbed, or is retained in the pores. As a result, the amount of rust inhibitor that moves toward the surface of the rust-preventive film is reduced or delayed, thereby reducing or delaying the rust-preventive effect.

[0018] Furthermore, the particles must have an average particle size of 5.0 to 200 μm. If the average particle size is smaller than 5.0 μm, it becomes difficult to transfer the rust inhibitor along the particle surface to the surface of the rust-preventive film. If the average particle size is larger than 200 μm, the mechanical strength of the rust-preventive film will decrease. Among particles having an average particle size of 5.0 to 200 μm, the average particle size is preferably 100 μm or less, more preferably 60 μm or less, even more preferably 30 μm or less, and most preferably 20 μm or less. Also, it is preferably 6.0 μm or more, and more preferably 7.0 μm or more. The average particle size is the value of the minor axis of the particles, and the average particle size of the major axis and the minor axis is D50 measured by image analysis using a CAMSIZER X2 manufactured by Microtrac.

[0019] The resin particles and inorganic particles are preferably spherical in shape, with an aspect ratio of 1.0 to 20.0 being desirable, since rod-shaped or flake-shaped particles may not be effective enough. If the aspect ratio exceeds 20.0, the particles tend to hinder the movement of the alkali metal carboxylate in the anticorrosive film toward the surface of the anticorrosive film, making it difficult to quickly release the anticorrosive agent and achieving a sufficient anticorrosive effect.

[0020] Furthermore, within the range of 1.0 to 20.0, the aspect ratio is preferably 18.0 or less, more preferably 10.0 or less, even more preferably 5.0 or less, and most preferably 2.0 or less. The particles are blended in the anticorrosive film in an amount of 0.05 to 5.00% by weight, preferably 0.20% by weight or more, more preferably 0.50% by weight or more, and even more preferably 0.70% by weight or more, and preferably 4.00% by weight or less, more preferably 3.00% by weight or less, even more preferably 2.00% by weight or less, and most preferably 1.50% by weight or less. If the particle content is less than 0.05% by weight, the effect of adding the particles will not be sufficient, and the anti-rust agent will be less likely to migrate toward the surface of the anti-rust film.If the particle content exceeds 5.00% by weight, the particles in the anti-rust film may affect the mechanical strength of the anti-rust film. In addition to the particles (C) of the present invention, other particles may be contained, but in that case, it is necessary to contain them within a range that does not impair the effect of the present invention. The effect of the present invention is preferably such that the corrosion area ratio after 7 days under the experimental conditions in the following examples is 0.10% or less, more preferably 0.08% or less.

[0021] In the rust-preventive film and rust-preventive layer of the present invention, the content of the (C) particles relative to the content of the (B) alkali metal carboxylate is preferably 0.05 to 100 times. Within this range, the presence of the (C) particles tends to facilitate the release of the (B) alkali metal carboxylate from the rust-preventive film and rust-preventive layer, thereby improving the rust-preventive effect. Furthermore, the content of the (B) alkali metal carboxylate relative to the content of the (C) particles is preferably 0.01 to 20 times. Within this range, the presence of the (C) particles tends to make it easier for the (B) alkali metal carboxylate to be released from the rust-preventive film, thereby improving the rust-preventive effect.

[0022] A rust-preventive film obtained by laminating a rust-preventive layer containing the above (A) to (C) and a substrate layer (D). The substrate layer (D) is a layer laminated on one side of the anticorrosive layer containing the above components (A) to (C). The anticorrosive layer may be provided on the entire surface or a part of the surface of the substrate layer, or conversely, the substrate layer may be provided on a part of the surface of the anticorrosive layer. When the substrate layer (D) is provided, the material to be rust-prevented is placed and / or wrapped in contact with the rust-preventive layer side, not the substrate layer side. The anti-rust film having a substrate layer can be formed by a general method for forming a laminate having multiple resin layers, such as by forming the substrate layer on one side of the anti-rust layer by lamination or co-extrusion, or by applying a solution or melt containing a material constituting one of the anti-rust layer and the substrate layer to one side of the other. The substrate layer is a material that can be laminated with the anti-rust layer, and is of a material and structure that does not interfere with the intended use of the anti-rust film, such as packaging. For example, the substrate layer can be made of known resins such as polyolefin resins, polyamide resins, vinyl chloride resins, polyester resins, acrylic resins, etc. The substrate layer can be in the form of a film or sheet, cloth, woven fabric, nonwoven fabric, etc. The substrate layer may be provided simply as a support layer without containing a rust inhibitor, or other known rust inhibitors including the above-mentioned alkali metal carboxylate and / or volatile rust inhibitor may be blended into the substrate layer. When coating a metal product to be rust-prevented with the rust-preventive film of the present invention, the substrate layer side may be placed facing the metal product to be rust-prevented, or conversely, the rust-preventive layer side may be placed facing the metal product to be rust-prevented.

[0023] Other ingredients Other components that can be blended into the anticorrosive film containing (A) to (C), the anticorrosive layer containing (A) to (C), and each layer of the anticorrosive film having a substrate layer (D) of the present invention include known additives that can be blended into resins, such as colorants, plasticizers, light stabilizers, slip agents, and antistatic agents, within the scope of not impairing the effects of the present invention. The anticorrosive film of the present invention can be produced by any known method for producing single-layer or multi-layer films.

[0024] The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to the following examples, and modifications can be made within the scope of the above and below-described aims, and all such modifications are included in the technical scope of the present invention.

[0025] (Contact corrosion prevention test (evaluated by determining the corrosion area ratio)) Test piece: Cast iron (Fc250, Φ30 x 9 mm thick disc shape) Test specimen packaging: Two anti-rust films measuring 60 mm in length and 90 mm in width were heat-sealed around the periphery, and the test specimen was inserted into a bag-like object, which was then suspended in a space under the test environment. Test environment: Temperature 50°C, humidity 95% Test duration: 1 day, 7 days, 30 days Evaluation criteria: Corrosion area ratio After the test, the test pieces were photographed using a Hirox KH-1300 digital microscope (6x magnification), and the image data was binarized using the image processing software ImageJ to determine the corrosion area ratio. Excellent contact corrosion prevention: corrosion area rate after 1, 7 or 30 days is 0.10% or less Contact corrosion prevention: Poor: Corrosion area ratio after 1, 7 or 30 days is 0.11% or more [Example]

[0026] Specific examples and comparative examples of the present invention will be described below. Tables 1 to 3 show the components used in the examples or comparative examples, and the values ​​in Table 4 and subsequent tables show the content (wt%) and results. Tables 7 and subsequent results show the corrosion area ratio results when A-1 was used as Agent A. Tables 5 to 10 show the results when a film thickness of 80 μm was used.

[0027] [Table 1]

[0028] [Table 2]

[0029] [Table 3] JPEG0007777539000004.jpg51121

[0030] [Table 4]

[0031] [Table 5]

[0032] [Table 6] JPEG0007777539000008.jpg57128

[0033] [Table 7]

[0034] [Table 8]

[0035] [Table 9]

[0036] [Table 10]

[0037] In Table 4, in Examples 1 to 8, when the polyolefin resins were A-1 to A-5, the combination of B-1 and C-1 exhibited high contact rust prevention power. In Table 5, Examples 9 to 15 are cases in which B-1 to B-5, which have a solubility of 0.1% or more in water at 50°C, were used as rust inhibitors, and as a result, the corrosion area ratio was 0%. In contrast, Comparative Example 1 used B-6, which has a solubility of less than 0.1%, and the corrosion area ratio was 0.15% after 1 day and 0.43% after 7 days, indicating that excellent rust prevention was not achieved. Comparative Example 2 is an example that does not contain Agent C, and the corrosion area ratio was 0.06% after 1 day and 0.19% after 7 days. In Table 6, Examples 16 to 27 are particles in which the average particle diameter (minor diameter) of Agent C is 5.0 to 200 μm, the aspect ratio is 1.0 to 20.0, and the specific surface area is 100 m 2 These are examples using particles C-1 to C-5 and C-8 to C-13 with an average particle diameter (minor axis) of 0.05 wt% or less, and the corrosion area ratio after one day was 0%. On the other hand, Comparative Examples 3 to 7 are examples using C-6, C-7, C-14 to C-16 with an average particle diameter (minor axis) of less than 5.0 μm, and as a result, the contact rust prevention power was reduced. Example 28 contains 0.05 wt% or more of particles with an average particle diameter of 5.0 μm or more, such as C-13, and therefore, even though it contains particles with an average particle diameter of less than 5.0 μm, such as C-14, the corrosion area ratio after one day was 0%. The corrosion area ratio after 7 days was 0.06%, and the contact rust prevention power was sufficient. In Table 7, when the content of C-11 in the rust-preventive film was 0 wt%, the corrosion area ratio was 0.06% when 1.0 wt% of B-1 was added. In contrast, even when the content of B-1 was reduced to 0.05 wt%, which is 1 / 20 of this amount, the corrosion area ratio was still approximately the same at 0.06%, as was the case when 0.05 wt% of C-11, which is not a rust inhibitor, was added. Furthermore, when 1 wt% of C-11 was added, the corrosion area ratio was reduced to 0%, an excellent effect was achieved, with only 0.05 wt% of B-1 being added. Similarly, in Table 8, when the content of C-11 in the rust-preventive film was 0 wt%, adding 1 wt% of B-1 resulted in a corrosion area ratio of 0.17%. In contrast, even when the B-1 content was reduced to 0.05 wt%, one-twentieth of this, by adding 0.05 wt% of C-11, which is not a rust inhibitor, the corrosion area ratio was 0.08%, further improving contact corrosion prevention. Furthermore, when C-11 was added at 1 wt%, the corrosion area ratio was 0.06%, demonstrating excellent effectiveness, even with just 0.05 wt% of B-1. In Table 9, when the content of C-11 in the rust-preventive film was 0 wt%, adding 1 wt% of B-1 resulted in a corrosion area ratio of 0.25%. In contrast, even when the content of B-1 was reduced to 0.05 wt%, one-twentieth of this amount, by adding 0.05 wt% of C-11, which is not a rust inhibitor, the contact corrosion prevention ability was further improved, and the corrosion area ratio was 0.10%. Furthermore, when C-11 was added at 1 wt%, the corrosion area ratio was 0.08% just by adding 0.05 wt% of B-1, demonstrating an excellent effect. These results show that by incorporating particles that are not rust inhibitors but have a specific average particle size, aspect ratio, and specific surface area, the amount of rust inhibitor required for rust prevention can be significantly reduced. Furthermore, as shown in Table 10, when C-11, a colloidal silica with an untreated surface, was used as Example 29, the corrosion area ratio was 0% after 1 day and 0.06% after 7 days. When C-2, a colloidal silica with a hydrophobic surface, was used as Example 30, the corrosion area ratio was 0.02% and 0.07% after 1 day and 7 days, respectively. However, when no colloidal silica was contained, as in Comparative Example 8, the corrosion area ratio was 0.13% and 0.26% after 1 day and 7 days, respectively. These results show that the untreated colloidal silica had slightly better contact corrosion prevention ability than the treated colloidal silica.

Claims

1. A rust-preventive film containing the following (A) to (C): (A) a polyolefin resin, (B) 0.05 to 0.50% by weight of an alkali metal carboxylate having an average particle size of 100 μm or less and a solubility in water at 50° C. of 0.1% by weight or more relative to the rust-preventive film; (C) an average particle size of 5.0 to 200 μm, an aspect ratio of 1.0 to 20.0, and a specific surface area of ​​100 m ２ / g or less particles are used in an amount of 0.05 to 5.00% by weight based on the anti-corrosion film.

2. 2. The rust-preventive film according to claim 1, wherein the carboxylic acid of the alkali metal carboxylic acid salt is an aliphatic carboxylic acid and / or an aromatic carboxylic acid.

3. 3. The rust-preventive film according to claim 1, wherein the carboxylic acid of the alkali metal carboxylic acid salt is at least one selected from the group consisting of a C8 to C16 saturated monocarboxylic acid, a C8 to C16 saturated dicarboxylic acid, a C8 to C22 unsaturated monocarboxylic acid, and a C8 to C22 unsaturated dicarboxylic acid.

4. 4. The anticorrosive film according to claim 1, wherein the particles are inorganic particles and / or resin particles.

5. An anti-corrosion film having an anti-corrosion layer containing the following (A) to (C) and (D) a substrate layer: (A) a polyolefin resin, (B) 0.05 to 0.50% by weight of an alkali metal carboxylate having an average particle size of 100 μm or less and a solubility in water at 50° C. of 0.1% by weight or more relative to the weight of the anticorrosive layer; (C) an average particle size of 5.0 to 200 μm, an aspect ratio of 1.0 to 20.0, and a specific surface area of ​​100 m ２ / g or less particles are used in an amount of 0.05 to 5.00% by weight of the anticorrosive layer.

6. 6. The rust-preventive film according to claim 5, wherein the carboxylic acid of the alkali metal carboxylic acid salt is an aliphatic carboxylic acid and / or an aromatic carboxylic acid.

7. 7. The rust-preventive film according to claim 5, wherein the carboxylic acid of the alkali metal carboxylic acid salt is at least one selected from the group consisting of a C8 to C16 saturated monocarboxylic acid, a C8 to C16 saturated dicarboxylic acid, a C8 to C22 unsaturated monocarboxylic acid, and a C8 to C22 unsaturated dicarboxylic acid.

8. 8. The anticorrosive film according to claim 5, wherein the particles are inorganic particles and / or resin particles.

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