Rust preventive 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.MEANS FOR SOLVING THE PROBLEM: 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 two or more kinds selected from the group consisting of an alkali agent that shows alkalinity and neutralizes an acidic substance, an antioxidant, fatty acids, and an acidic gas adsorbent for adsorbing acidic gas.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a rust-preventive film for suppressing rust generation on packaged contents, a packaging material, and a package produced using the rust-preventive film. The rust-preventive film according to the present invention can be applied to products in various fields, and in particular, it can be suitably used as a packaging material for accommodating metal products such as in-vehicle screws, shafts, metal plates, etc., and electrical components.

Background Art

[0002] Packaging materials for the purpose of transporting and long-term storing metal products made of metal materials or parts using metal are being developed. There is a demand for a packaging material that has a higher and more stable rust-preventive property so as to maintain the functions and properties of the metal products as the contents, and can be manufactured by a simple manufacturing process with a simple layer structure. For the purpose of rust prevention for metal product contents, packaging laminates containing a highly volatile rust-preventive agent that volatilizes at room temperature and exhibits a rust-preventive effect in a resin are described in Patent Documents 1 to 3. However, when sealing by an exterior is required or when the volatilized rust-preventive agent adheres to the contents, there are concerns about effects other than the rust-preventive effect, such as the contents deteriorating or having a functional failure, and it is troublesome to remove the adhered rust-preventive agent, so the use is limited, and a rust-preventive film that does not use a volatile rust-preventive agent is desired.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present invention solves the above problems, has excellent manufacturing suitability, has a simple layer structure, and provides a rust-preventive film capable of suppressing rust generation in the contents during transportation and long-term storage, a rust-preventive packaging material, and a rust-preventive package produced using the rust-preventive film.

Means for Solving the Problems

[0005] As a result of various studies, the present inventors have found that a rust-preventive film containing at least a rust inhibitor defined in the present invention and a binder resin can achieve the above object. That is, the present invention is characterized by the following points. 1. A single-layer rust-preventive film containing at least a rust inhibitor and a binder resin, wherein the rust inhibitor contains at least an alkali agent for neutralizing an acidic substance by exhibiting alkalinity, an antioxidant, one or more selected from the group consisting of fatty acids, metal fatty acids, and fatty acid esters, an acidic gas adsorbent for adsorbing acidic gas, and contains two or more selected from the group consisting of these, and is characterized as a rust-preventive film. 2. A multi-layer rust-preventive film having at least a rust-preventive layer, wherein the rust-preventive layer contains a rust inhibitor and a binder resin, the rust inhibitor contains at least an alkali agent for neutralizing an acidic substance by exhibiting alkalinity, an antioxidant, one or more selected from the group consisting of fatty acids, metal fatty acids, and fatty acid esters, an acidic gas adsorbent for adsorbing acidic gas, and contains two or more selected from the group consisting of these, and a layer containing a thermoplastic resin is laminated on one or both sides of the rust-preventive layer, and is characterized as a rust-preventive film. 3. The rust preventive film according to 2 above, characterized in that the rust preventive film is a coextruded film. 4. The rust preventive film according to 2 or 3 above, characterized in that the rust preventive film further has an intermediate layer. 5. The rust preventive film according to any one of 1 to 4 above, characterized in that the alkali agent contains one or more selected from the group consisting of alkali metal compounds, alkaline earth metal compounds, and aluminum compounds. 6. The rust preventive film according to any one of 1 to 5 above, characterized in that the antioxidant contains a phenolic antioxidant and / or a phosphorus-based antioxidant. 7. The rust preventive film according to any one of 1 to 6 above, characterized in that the fatty acid, metal fatty acid, or fatty acid ester has 6 to 20 carbon atoms in the fatty acid moiety. 8. The rust preventive film according to any one of 1 to 7 above, characterized in that the acid gas adsorbent contains one or more selected from the group consisting of hydrophobic zeolite, metal-supported zeolite, and amino group-supported porous body. 9. A rust preventive packaging material, characterized in that it is made of the rust preventive film according to any one of 1 to 8 above. 10. A rust preventive package, characterized in that it is made of the rust preventive packaging material according to 9 above.

Advantages of the Invention

[0006] The rust preventive film of the present invention, the rust preventive packaging material and the rust preventive package produced using the rust preventive film solve the above-mentioned problems, are excellent in manufacturing suitability, and have a simple layer structure. During transportation and long-term storage, it is possible to provide a rust preventive film that can suppress rust from occurring on the contents, and a rust preventive packaging material and a rust preventive package produced using the rust preventive film.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

[0008] In each figure, for the sake of clarity, the size and ratio of the members may be changed or exaggerated for description. Also, for the sake of visibility, parts that are not necessary for explanation and repeated reference numerals may be omitted. Although omitted in each figure, an adhesive layer can also be provided between each layer. Furthermore, if necessary, in order to strengthen the adhesive strength (adhesion strength) between each layer, physical surface treatments such as corona discharge treatment, ozone treatment, plasma treatment, glow discharge treatment, sandblasting treatment, etc., and chemical surface treatments such as oxidation treatment using chemical agents can be performed in advance on the laminated surfaces of each layer.

Embodiments for Carrying Out the Invention

[0009] The rust-preventive film, rust-preventive packaging material, and rust-preventive package of the present invention will be further described in detail below. Although described with specific examples, the present invention is not limited thereto. In the present invention, the film and the sheet are treated as synonyms.

[0010] ≪Rust-Preventive Film≫ The rust-preventive film of the present invention is a resin film containing at least a rust inhibitor and a binder resin and having heat sealability. Also, 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 selected from the group consisting of "an alkaline agent for neutralizing an acidic substance exhibiting alkalinity", "an antioxidant", "one or more selected from the group consisting of fatty acids, metal fatty acids, and fatty acid esters", "an acidic gas adsorbent for adsorbing acidic gas", etc. By using two or more rust inhibitors in combination, the rust-preventive effect can be efficiently exhibited. Hereinafter, fatty acids, metal fatty acids, and fatty acid esters are also referred to as fatty acid compounds as a general term. In order to suppress the generation of rust, acidic gas invading from the outside or acidic gas existing in the enclosed internal space is adsorbed by the rust preventive film, or a rust preventive agent is adhered or coated on the surface of the contents, thereby imparting water repellency to the surface of the contents, preventing oxidation of the surface of the contents, or neutralizing acidic gas contacting the surface of the contents. This is effective. By using the above-mentioned rust preventive agents in combination, these methods can be used in combination to efficiently exhibit the rust preventive effect.

[0011] There is no particular limitation on the thickness of the rust preventive film, but it 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 exhibit a sufficient balance of supportability, rust preventive effect, and heat sealability. If it is thicker than the above range, the rigidity is too strong and the usability as a packaging material tends to deteriorate.

[0012] The rust preventive film can have high transparency according to the application. The total light transmittance of the rust preventive film with high transparency is preferably 50% or more. The transparency of the rust preventive packaging material made of the rust preventive film with high transparency is also high. The rust preventive package made of the rust preventive packaging material with high transparency can easily visually recognize the contents, the label attached to the contents, the characters and seals printed on the contents, etc.

[0013] The rust preventive film can contain various plastic compounding agents, additives, etc. for the purpose of improving and modifying, for example, processability, heat resistance, weather resistance, mechanical properties, dimensional stability, antioxidant properties, slipperiness, releasability, flame retardancy, antibacterial properties, electrical properties, strength, etc. The content can be arbitrarily contained from a very small amount to several tens of %, depending on the purpose. In the above, general additives can include, for example, antiblocking agents, lubricants, crosslinking agents, antioxidants, ultraviolet absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, pigments, modifying resins, etc.

[0014] When the rust preventive film of the present invention is a single-layer rust preventive film, it contains at least a rust preventive agent and a binder resin in one layer. When the binder resin has heat sealability, the surface of one side or both sides of the single-layer rust preventive film can have heat sealability. The rust preventive agent may be uniformly dispersed in one layer or may be dispersed with a concentration gradient. For example, when a concentration gradient is provided such that there is a large amount of rust preventive agent near the surface of one side and a small amount of rust preventive agent near the surface of the other side, the surface of the side with a large amount of rust preventive agent can easily exhibit rust prevention efficiency, and the surface of the side with a small amount of rust preventive agent has high heat sealability. By reducing the concentration of the rust preventive agent overall or increasing the concentration of the rust preventive agent in the central part of the layer, the heat sealability of both sides of the rust preventive film can also be enhanced. The content of the rust preventive agent in the rust preventive film is preferably 0.1% by mass or more and 50% by mass or less. If it is less than the above range, it is difficult to exhibit a sufficient rust prevention effect, and if it is greater than the above range, the film forming property and heat sealability 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 preventive agent and a binder resin. The binder resin is a thermoplastic resin. When the binder resin has heat sealability, one side or both sides of the rust preventive layer can have heat sealability. Also, it is preferable that a layer containing a thermoplastic resin is laminated on one side or both sides of the rust preventive layer. The multi-layer rust preventive film can have an intermediate layer and an outer layer that exhibit various functions according to the application, for example. In this case, the rust preventive film is preferably laminated in the order of the rust preventive layer, the intermediate layer, and the outer layer. And each layer may be laminated via an adhesive layer. The rust preventive film suppresses rust generation of the contents by having a rust preventive layer. For example, if the thermoplastic resin contained in the outer layer is a heat-sealable resin, the multilayer rust-preventive film can have heat-sealability. The rust preventive agent 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 such that there is a large amount of the rust preventive agent near the surface of one side and a small amount of the rust preventive agent near the surface of the other side, the surface on the side with a large amount of the rust preventive agent can easily exhibit rust prevention efficiency, and the surface on the side with a small amount of the rust preventive agent has high heat-sealability. By reducing the concentration of the rust preventive agent overall or increasing the concentration of the rust preventive agent in the central part of the rust preventive layer, the adhesiveness of both interfaces of the rust preventive layer can be enhanced. The content of the rust preventive agent in the rust preventive layer is preferably 0.1% by mass or more and 50% by mass or less. If it is less than the above range, it is difficult to exhibit a sufficient rust prevention effect, and if it is greater than the above range, the film-forming property and heat-sealability are likely to be inferior.

[0016] For the multilayer rust-preventive film, it is preferable that the surface of one side or both sides is a rust preventive layer. Since the rust preventive layer is on the surface, it becomes easier to adhere or coat the rust prevention property on the surface of the contents. Note that when the surface is a rust preventive layer, it means that all or part of the rust preventive layer is exposed on the surface.

[0017] <Rust preventive agent> The rust preventive agent is a compound that suppresses the occurrence of rust in the contents packaged by the rust-preventive film of the present invention. The rust preventive agent in the present invention remains inside the rust-preventive film of the present invention to adsorb acidic gas, or adheres to the surface of the contents packaged from the rust-preventive film of the present invention by vaporization, scattering, or contact transfer, and neutralizes acidic substances, repels water to suppress the adhesion of moisture, and suppresses oxidation on the surface of the contents, thereby suppressing the occurrence of rust.

[0018] In the present invention, the rust preventive preferably contains two or more selected from the group consisting of "an alkaline agent for neutralizing acidic substances by exhibiting alkalinity", "an antioxidant", "one or more selected from the group consisting of fatty acids, metal fatty acids, and fatty acid esters", and "an acidic gas adsorbent for adsorbing acidic gas". When two or more are used in combination, different effects such as acidic gas adsorption, acidic substance neutralization, water repellency, and oxidation inhibition synergistically contribute, and the rust prevention property is synergistically improved. Examples of the combination of rust preventives to be contained include an antioxidant and an alkaline agent, an antioxidant and fatty acids, an antioxidant, an alkaline agent and fatty acids, an alkaline agent and fatty acids, an alkaline agent and an acidic gas adsorbent, fatty acids and an acidic gas adsorbent, etc. are preferable.

[0019] Details of various types of rust preventives 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 exhibits alkalinity by itself, adheres to the surface of the content to be packaged, neutralizes acidic substances that cause rust generation, and can suppress the generation of rust. Examples of the composition of the alkaline agent include alkali metal compounds, alkaline earth metal compounds, and aluminum compounds. The alkali metal in the present invention is an alkali metal in a broad sense, and refers to Li, Na, K, Rb, Cs, Fr which are metal elements of Group 1, and among these, Li, Na, and K are preferable. In addition, the alkaline earth metal is an alkaline earth metal in a broad sense, and refers to Be, Mg, Ca, Sr, Ba, Ra which are metal elements of Group 2.

[0021] Examples of the alkali metal compound include alkali metal oxides, alkali metal chlorides, alkali metal hydroxides, etc. Specific examples of the alkali metal compound include Li 2 O, Na 2 O, K 2 O, LiCl, LiOH, etc. Among these, Na 2 O, K 2O is preferred.

[0022] Examples of the alkaline earth metal compound include alkaline earth metal oxides, alkaline earth metal chlorides, alkaline earth metal hydroxides, etc. Specific examples of the alkaline earth metal compound include BeO, MgO, CaO, SrO, BaO, RaO, MgCl 2 , CaCl 2 , 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 Al 2 O 3 , Al(OH) 3 etc. Among these, Al 2 O 3 is preferred.

[0024] Among the above specific alkalis, it is preferable to use one or more selected from the group consisting of MgO, CaO, Mg(OH) 2 , Ca(OH) 2 , Al 2 O 3 .

[0025] The alkali is used in powder form, and the average particle diameter based on the number of powder particles is preferably 0.1 μm or more and 20 μm or less. If the average particle diameter is smaller than the above range, the alkali is likely to aggregate, and if it is larger than the above range, the surface area is small, so there is a risk of inferior rust prevention performance. The content of the alkali contained in the rust prevention layer of the single-layer rust prevention film or the multi-layer rust prevention film is preferably 15% by mass or more and 50% by mass or less. If it is less than the above range, it is difficult to exhibit a sufficient rust prevention effect, and if it is larger than the above range, the film-forming property and heat sealability are likely to be inferior.

[0026] [Antioxidant] The antioxidant in the present invention can adhere to the surface of the content to be packaged and suppress the generation of rust due to oxidation of the content surface. As the antioxidant, known and publicly used antioxidants for packaging materials can be used. However, phenolic antioxidants and phosphorus-based antioxidants are preferred, and among these, those having a hydrophilic group and a hydrophobic group are more preferred.

[0027] As a specific phenolic antioxidant, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] is preferred. As specific phosphorus-based antioxidants, tris(2,4-di-tert-butylphenyl)phosphite and 2,4,8,10-tetra-tert-butyl-6-(3-(3-methyl-4-hydroxy-5-tert-butylphenyl)propoxy)dibenz(d,f)(1,3,2)dioxaphosphepine are preferred.

[0028] The content of the antioxidant contained in the rust-preventive film of a single layer or the rust-preventive layer of a multilayer rust-preventive film is preferably 0.1% by mass or more and 15% by mass or less. If it is less than the above range, it is difficult to exhibit a sufficient rust-preventive effect. Even if it is larger than the above range, the rust-preventive effect is not improved so much, and the film-forming property and heat-sealing property are likely to deteriorate, which is not preferable.

[0029] [Fatty acids] The fatty acids in the present invention can adhere to the surface of the content to be packaged, exhibit a water-repellent effect, and suppress the adhesion of moisture, which is a cause of rust generation, to the content surface, thereby suppressing the generation of rust. Specific examples of the fatty acids include fatty acids, metal fatty acids, and fatty acid esters. It is considered that the fatty acids exhibit water repellency because the aliphatic chain part functions as a hydrophobic group, the hydrophilic group functions as the carboxylic acid part, the hydrophilic group adheres to the content surface, and the hydrophobic group part adheres outward. As for the composition of fatty acids, those having 6 to 20 carbon atoms in the fatty acid moiety are preferred. If the number of carbon atoms is less than the above range, there is a risk that the boiling point is too close to the film-forming temperature, resulting in the generation of bubbles or the inability to form a film. If the number of carbon atoms is more than the above range, there is a risk that vaporization, scattering, and adhesion by contact transfer to the surface of the contents packaged in the rust-preventive film are less likely to occur. Specific fatty acids include caproic acid, heptanoic acid, nonanoic acid, octanoic acid, decanoic acid, undecylic acid, lauric acid, stearic acid, nonadecylic acid, arachidic acid, and the like.

[0030] Specific metal fatty acids include alkali metal salts and alkaline earth metal salts of the above fatty acids, etc., and Ca salts are preferred. Specific fatty acid esters include alcohol esters and glycerin fatty acid esters of the above fatty acids, etc. Glycerin fatty acid esters are preferably glycerin tri-fatty acid esters, glycerin fatty acid esters are preferred, and glycerin tri-caprylate is more preferred. Among the above fatty acids, it is preferable to use one or more selected from the group consisting of heptanoic acid, octanoic acid, decanoic acid, lauric acid, stearic acid, caprylic acid, capric acid, calcium stearate, and glycerin tri-caprylate. The content of fatty acids contained in the rust-preventive layer of a single-layer rust-preventive film or a multi-layer rust-preventive film is preferably 0.1% by mass or more and 30% by mass or less. If it is less than the above range, it is difficult to exhibit a sufficient rust-preventive effect. Even if it is larger than the above range, the rust-preventive effect is not improved so much, and the film-forming property and heat-sealability are likely to be inferior, which is not preferable.

[0031] [Acid gas adsorbent] The acid gas adsorbent in the present invention adsorbs acid gases such as SO x , NO x , carbon dioxide gas, etc., and can suppress the surface of the contents to be packaged from generating rust due to these acid gases. The rust-preventive film contains an acidic gas adsorbent, which can suppress the penetration of these acidic gases from outside the package through the rust-preventive film and into the package, or adsorb these acidic gases present in the content storage part inside the package to reduce their concentration. The acidic gas adsorbent preferably contains one or more selected from the group consisting of hydrophobic zeolite, metal-supported zeolite, and amino group-supported porous body. The acidic gas adsorbent may have any external shape such as spherical, rod-shaped, or elliptical, and may be in any form such as powder, lump, or granule. However, from the viewpoints of uniform dispersibility, kneading characteristics, film-forming properties, etc. when dispersed in the resin, the powder form is preferred.

[0032] The acidic gas adsorbent is used in powder form, and the average particle diameter based on the number of powder particles is preferably 0.1 μm or more and 20 μm or less. Here, the average particle diameter is the value measured by the dynamic light scattering method. If the average particle diameter is smaller than the above range, the acidic gas adsorbent is likely to aggregate. If it is larger than the above range, the surface area becomes smaller, and there is a risk of inferior rust prevention performance. The content of the acidic gas adsorbent contained in the rust-preventive layer of the single-layer rust-preventive film or the multi-layer rust-preventive film is preferably 0.1% by mass or more and 30% by mass or less. If it is less than the above range, it is difficult to exhibit a sufficient rust prevention effect. Even if it is larger than the above range, the rust prevention effect does not improve much, and the film-forming properties and heat sealability are likely to be inferior, so it is not preferable.

[0033] (Hydrophobic zeolite) The hydrophobic zeolite is a porous body, and the higher the molar ratio of the constituent components SiO 2 / Al 2 O 3 , the higher the hydrophobicity. Hydrophobic zeolites with a SiO 2 / Al 2 O 3 molar ratio of 30 / 1 to 10000 / 1 are preferred. Due to its high hydrophobicity, it has a high performance of adsorbing low-polarity acidic gases without adsorbing highly polar water vapor. In the present invention, from the balance between the moisture absorption performance and the ease of availability, zeolite having a molar ratio within the above range is preferably used. Hydrophobicity Zeolite is preferably used.

[0034] (Metal-supported zeolite) Metal-supported zeolite is zeolite supporting a metal different from Si and 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 the metal atoms themselves. In the present invention, it is referred to as metal-supported zeolite as a general term for both metal oxide-supported zeolite and metal atom-supported zeolite. When a gas component that generates rust touches the metal-supported zeolite, the gas component is ionized, bonded, decomposed, oxidized, reduced, or undergoes any other reaction, and it is considered to lose its ability to generate rust. As the metal species to be supported, those that are difficult to react with moisture and have a lower ionization tendency than iron are preferred. Specifically, one or more selected from the group consisting of copper, zinc, silver, platinum, etc. are preferred, and one or more selected from the group consisting of copper, zinc, and silver are more preferred. Also, the supported zeolite may be either hydrophilic zeolite or hydrophobic zeolite.

[0035] (Amino group-supported porous body) The amino group-supported porous body is obtained by supporting a chemisorbent having an amino group on a porous body. As the supporting method, a known or conventional supporting method can be applied. For example, it can be supported by impregnating a porous body with a solution containing a chemisorbent and then drying it. The amino group-supported porous body selectively reacts with an aldehyde compound or the like at the amino group part and adsorbs, and physical adsorption characteristics with respect to the pore part of the porous body can also be expected. As the porous body for carrying an amino group, any compound having a large number of pores on its surface can be used, and an inorganic porous body is preferable. Examples thereof include inorganic phosphates such as zeolite, silicon dioxide, silicate, activated carbon, titania, calcium phosphate, alumina, aluminum hydroxide, magnesium hydroxide, and mixtures thereof. In particular, from the viewpoint of having a porous state with a pore size effective for the molecular size and cluster size of the substance to be adsorbed and from the viewpoint of safety, it is preferable to use aluminum hydroxide, zeolite, or silicate.

[0036] [Method for dispersing rust inhibitor] The rust inhibitor is preferably contained via a masterbatch obtained by melt-blending the rust inhibitor with a thermoplastic resin. Specifically, it is preferable to prepare a masterbatch by melt-blending the rust inhibitor with a thermoplastic resin at a relatively high concentration, and then dry-blend the masterbatch with components such as a binder resin so as to obtain the rust inhibitor concentration. Each of the rust inhibitor and the thermoplastic resin to be melt-blended may be one kind or two or more kinds, and one kind or two or more kinds of rust inhibitors may be contained in one masterbatch. The content of the rust inhibitor in the masterbatch 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 still 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-mentioned 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 preferably has an affinity suitable for the dispersion of the rust inhibitor and is excellent in film-forming properties, and more preferably has heat-sealing properties.

[0038] ​As specific binder resins, polyolefin resins, polyester resins, polyamide resins, polyaramide resins, polycarbonate resins, polyacetal resins, fluorine resins, ethylene-vinyl acetate copolymers, ethylene-vinyl alcohol copolymers (EVOH), polyvinyl alcohol, polyacrylonitrile, and other resins are preferable. These resins may be used alone or in combination of two or more. Among these resins, polyolefin resins are preferable from the viewpoint of film-forming properties.

[0039] Specific examples of polyolefin resins include polyethylene resins, polypropylene resins, unsaturated carboxylic acid-modified polyolefin resins, cyclic polyolefin resins, cyclic olefin copolymers, etc. As the unsaturated carboxylic acid, 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, and may also be used in a multilayer containing resins of different types. These copolymerizable unsaturated carboxylic acids may be used alone or in combination of two or more. Among these polyolefin resins, polyethylene resins are preferable 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 (linear) low-density polyethylene (LLDPE), metallocene polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-(meth)acrylate copolymer, ethylene-(meth)acrylic acid copolymer, ethylene-propylene copolymer, methylpentene polymer, unsaturated carboxylic acid-modified 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 resins, low-density polyethylene (LDPE) and linear (linear) low-density polyethylene (LLDPE) are more preferred, and linear (linear) low-density polyethylene (LLDPE) is even more preferred. These polyethylene resins may be used alone or in combination of two or more.

[0041] <Rust preventive layer> The rust preventive layer is a layer containing a rust preventive agent and a binder resin in a multilayer rust preventive film. There is. The binder resin contained in the rust preventive layer is made of a thermoplastic resin and may or may not have heat sealability. When it has heat sealability, it is preferably contained with a heat sealable resin, or the binder resin may contain a heat sealable resin. The rust preventive layer may be a single layer containing two or more rust preventive agents, or may be composed of two or more layers containing different types and contents of rust preventive agents. The rust preventive layer is preferably laminated on the surface of the multilayer rust preventive film. By being laminated on the surface, the rust preventive property can be easily exhibited.

[0042] The content of the rust preventive agent in the rust preventive layer is preferably 0.1% by mass or more and 50% by mass or less. If it is less than the above range, it is difficult to exhibit a sufficient rust preventive effect, and if it is greater than the above range, the film forming property and heat sealability are likely to be inferior. 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 60 μm or less. If it is thinner than the above range, there is a risk that a sufficient rust preventive action cannot be exhibited, and even if it is thicker than the above range, the rust preventive effect is not improved so much, and there is a risk that the rigidity of the entire rust preventive film becomes too strong and it becomes difficult to use.

[0043] <Intermediate layer> The intermediate layer can have various layers that can impart mechanical, physical, and chemical functions, such as supportability, rigidity, flexibility, pinhole resistance, etc., to the rust preventive film. For example, by having a water vapor barrier layer, it is possible to suppress the intrusion of moisture into the content storage part in the package, adsorb the moisture in the content storage part to lower the humidity, suppress condensation, and impart excellent rust prevention properties to the contents. Specific examples of the water vapor barrier layer include an inorganic vapor deposition layer and a metal foil layer.

[0044] Also, for example, resins for enhancing supportability include polyolefin resins, polyester resins, polyamide resins, polyaramide resins, polycarbonate resins, polyacetal resins, fluorine resins, ethylene-vinyl acetate copolymers, ethylene-vinyl alcohol copolymers (EVOH), polyvinyl alcohol, polyacrylonitrile, and other tough thermoplastic resins. These resins may be used alone or in combination of two or more, or may be used in a multilayer containing different types of resins. Among these resins, from the viewpoint of film-forming properties, polyolefin resins are preferred.

[0045] Specific examples of polyolefin resins include polyethylene resins, polypropylene resins, unsaturated carboxylic acid-modified polyolefin resins, cyclic polyolefin resins, cyclic olefin copolymers, etc. As the unsaturated carboxylic acid, 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 may be used in a multilayer containing different types of resins. These copolymerizable unsaturated carboxylic acids may be used alone or in combination of two or more. Among these polyolefin resins, from the viewpoint of film-forming properties, polyethylene resins are preferred.

[0046] Specific examples of the polyethylene-based resin include low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), linear (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, and the like. 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 (linear) low-density polyethylene (LLDPE) are more preferable, and linear (linear) low-density polyethylene (LLDPE) is even more preferable. These polyethylene-based resins may be used alone or in combination of two or more.

[0047] The thickness of the intermediate layer can be appropriately set by those skilled in the art. When the purpose is to impart appropriate strength and stiffness to the laminate, it 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 layer is a layer containing a thermoplastic resin. A variety of resins can be used for the thermoplastic resin used in the outer layer as long as it does not have a significant adverse effect on the heat sealability and film-forming property of the entire film. Specific examples of the thermoplastic resin include, for example, polyolefin-based resins such as general-purpose polyethylene, polypropylene, methylpentene polymer, acid-modified polyolefin-based resin, and mixtures of these resins, but are not limited to these resins, and the type of thermoplastic resin can be selected according to the purpose. The outer layer is preferably laminated on the surface of the rust-proof film having a multilayer structure. The thickness of the outer layer is not particularly limited, but is preferably 10 μm or more and 100 μm or less. Within the above range, there is little risk of significantly affecting the heat sealability and film-forming property 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 as long as it can be melted and fused by heat, and known heat-sealable resins can be used. Specific examples of the heat-sealable resin include polyethylene, low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear (linear) low-density polyethylene, metallocene polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ionomer resin, ethylene-(meth)acrylic acid ethyl copolymer, ethylene-(meth)acrylic acid copolymer, ethylene-propylene copolymer, methylpentene polymer, polyolefin resins such as polyethylene or polypropylene modified with unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic anhydride, fumaric acid, etc., ethylene-(meth)acrylate-unsaturated carboxylic acid terpolymer resin, cyclic polyolefin resin, cyclic olefin copolymer, polyethylene terephthalate (PET), polyacrylonitrile (PAN), and the like. Among these, polyolefin resins are preferred, among which polyethylene resins are more preferred, and among polyethylene resins, low-density polyethylene (LDPE) and linear (linear) low-density polyethylene (LLDPE) are even more preferred, and linear (linear) low-density polyethylene (LLDPE) is particularly preferred.

[0050] <Adhesive layer> There is no particular limitation on the adhesive used for the adhesive layer, and adhesives for DL (dry lamination), EC (extrusion coating), non-solvent lamination, any anchor coating agent, etc. can be used. Also, the adhesive can be any of thermosetting type, ultraviolet curing type, electron beam curing type, etc., water It may be in any form such as a solution type, emulsion type, dispersion type, etc., and its properties may be in any form such as film / sheet form, powder form, solid form, etc. Furthermore, regarding the adhesion mechanism, it may be in any form such as a chemical reaction type, solvent evaporation type, hot melt type, hot press type, etc.

[0051] Examples of the components for forming such an adhesive layer include polyvinyl acetate-based adhesives such as polyvinyl acetate and vinyl acetate-ethylene copolymers, polyacrylic acid-based adhesives composed of copolymers of polyacrylic acid and polystyrene, polyester, polyvinyl acetate, etc., cyanoacrylate-based adhesives, ethylene copolymer-based adhesives composed of copolymers of ethylene and monomers such as vinyl acetate, ethyl acrylate, acrylic acid, methacrylic acid, etc., 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 composed of urea resin or melamine resin, etc., phenol resin-based adhesives, epoxy-based adhesives, reactive (meth)acrylic-based adhesives, elastomer-based adhesives composed of chloroprene rubber, nitrile rubber, styrene-butadiene rubber, etc., silicone-based adhesives, inorganic-based adhesives composed of alkali metal silicate, low melting point glass, etc.

[0052] <Method for producing rust preventive film> The method for manufacturing the rust preventive film of the present invention will be described. The manufacturing method shown below is an example and does not limit the present invention. The rust preventive film can be produced by any method such as the T-die extrusion method, extrusion inflation method, or others. When the rust preventive film has a multilayer structure, the lamination of each layer can be carried out by any method used when manufacturing ordinary packaging materials, for example, the wet lamination method, dry lamination method, solventless dry lamination method, extrusion lamination method, co-extrusion lamination method, T-die co-extrusion method, co-extrusion inflation method, or others. Among the above, the multilayer rust-preventive film is preferably a coextruded film produced by a method including coextrusion. When performing the above lamination, if necessary, pretreatment such as corona treatment or ozone treatment can be applied to the surface of each layer. Also, for example, anchor coating agents such as isocyanate-based (urethane-based), polyethyleneimine-based, polybutadiene-based, and organic titanium-based, or anchor coating agents such as polyurethane-based, polyacrylic-based, polyester-based, epoxy-based, polyvinyl acetate-based, cellulose-based, and other laminating adhesives can be optionally used.

[0053] For example, the case of producing a rust-preventive film by the inflation method will be described. When the rust-preventive film is single-layered, 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 multilayered, first, resin compositions for forming each of the rust-preventive layer, intermediate layer, and outer layer are prepared. Then, by inflation film formation, the rust-preventive layer, intermediate layer, and outer layer are coextruded and laminated to produce a multilayer rust-preventive film. And further, an aging treatment may be performed as necessary. In this way, a laminate for packaging liquid contents or a packaging material for liquid contents can be produced. And the obtained rust-preventive film may be stretched in one axial direction or two axial directions as necessary.

[0054] Secondary processing can be performed on the rust-preventive film 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, adhesion, printing, metallization (such as plating), machining, surface treatment (antistatic treatment, corona discharge treatment, plasma treatment, photochromism treatment, physical vapor deposition, chemical vapor deposition, coating, etc.). In addition, the rust preventive film can also be subjected to lamination processing (dry lamination or extrusion lamination), bag making processing, and other post-treatment processing.

[0055] ≪Rust preventive packaging material≫ The rust preventive packaging material of the present invention is a packaging material made from the rust preventive film of the present invention, and may further include layers having various functions as required. The rust preventive packaging material has the same rust prevention property as the rust preventive film, and can be used, for example, as a stretch film.

[0056] ≪Rust preventive packaging body≫ 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 are no particular restrictions on the shape and form of the rust preventive packaging body of the present invention. The rust preventive packaging material can be bent, overlapped to wrap the contents, heat-sealed, etc. to form various shapes and forms, and added value can be imparted by printing and decoration. For example, a pouch-shaped rust preventive packaging body can be made with less rust preventive packaging material compared to a bottle-shaped rust preventive packaging body, which is effective for resource saving.

[0057] The pouch-shaped rust preventive packaging body can be formed by, for example, folding the rust preventive packaging material in half, or preparing two pieces of the rust preventive packaging material, overlapping them with the heat-sealable layer surfaces facing each other, and then heat-sealing the peripheral edges thereof by a heat-sealing form such as a side seal type, two-side seal type, three-side seal type, four-side seal type, envelope paste seal type, palm paste seal type (pillow seal type), pleat seal type, flat bottom seal type, corner bottom seal type, gusset type, etc. to create various shapes of rust preventive packaging bodies. In the above, as the heat seal method, for example, known methods such as bar seal, rotary roll seal, belt seal, impulse seal, high-frequency seal, ultrasonic seal, etc. can be used.

[0058] In the rust preventive package, it is preferable that the rust preventive layer of the rust preventive packaging material is packaged on the inside of the rust preventive package and the outer surface layer is packaged so as to be located on the inside. By being packaged in this way, the rust preventive package can efficiently suppress the penetration of acidic gas from the outside, or attach a rust preventive agent to the surface of the contents to suppress the generation of rust on the contents. When manufacturing the rust preventive package, it may be sealed while sucking the air inside the package or while replacing the content space with air having a low oxygen rate or low humidity.

Examples

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

[0060] [Antioxidant] · Antioxidant 1: Phenolic antioxidant A060 manufactured by Adeka Corporation. · Antioxidant 2: Phosphorus-based antioxidant 2112 manufactured by Adeka Corporation. · Antioxidant 3: Phenol + phosphorus-based mixed antioxidant A-612RG manufactured by Adeka Corporation.

[0061] [Alkali agent] · Alkali agent 1: Calcium oxide HAL-J manufactured by Yoshizawa Lime Industry Co., Ltd. Average particle size 1 - 2 μm. · Alkali agent 2: Magnesium oxide StarMag PSF-150 manufactured by Kojima Chemical Industry Co., Ltd. Average particle size 0.6 μm. · Alkali agent 3: Calcium hydroxide manufactured by Inoue Lime Industry Co., Ltd., average particle size 3 μm

[0062] [Fatty acids] · Fatty acid 1: Heptanoic acid manufactured by FUJIFILM Wako Pure Chemical Corporation. · Fatty acid 2: Stearic acid manufactured by FUJIFILM Wako Pure Chemical Corporation. · Metal fatty acid 1: Calcium stearate manufactured by FUJIFILM Wako Pure Chemical Corporation. · Fatty acid ester 1: Triglyceride, Actamer M2, manufactured by Riken Vitamin Co., Ltd.

[0063] [Acid gas adsorbent] · Acid gas adsorbent 1: Zeolite supported with copper oxide and zinc oxide, Dashlite CZU, manufactured by Shinandenzyme Omic Co., Ltd. Chemical reaction type. · Acid gas adsorbent 2: Silver supported zeolite, Zeomic Ag10D, manufactured by Shinandenzyme Omic Co., Ltd. Chemical reaction type.

[0064] [Binder resin, thermoplastic resin] · LLDPE1: LLDPE, Evolue SP2020, manufactured by Prime Polymer Co., Ltd. Density 0.916 g / cm 3 , MFR = 2.0 g / 10 min. · LDPE1: LDPE, Novatec LC520, manufactured by Japan Polyethylene Corporation. Density 0.923 g / cm 3 , MFR 3.6 g / 10 min.

[0065] <Preparation of masterbatch> The masterbatch was prepared as follows. [Preparation of masterbatch 1] LDPE1 and rust inhibitor 1 were melt-blended at the following ratio to obtain masterbatch 1 (MB1). LDPE1 95 parts by mass Antioxidant 1 40 parts by mass

[0066] [Adjustment of masterbatches 2 to 12] According to the formulation in Table 1, melt-blending was performed in the same manner as for masterbatch 1 to obtain masterbatches 2 to 12 (MB2 to 12).

[0067]

Table 1

[0068] <Example> A rust preventive film containing two or more types of rust preventives was produced and various evaluations were carried out.

[0069] [Example 1] MB1, MB4, and LLDPE1 were dry-blended at the following ratios to obtain a rust preventive layer resin composition. MB1 10 parts by mass MB4 50 parts by mass LLDPE1 40 parts by mass The rust preventive layer resin composition obtained above and LLDPE1 were formed into a film and laminated by inflation molding at 160 °C to obtain a rust preventive film (60 μm thick) having the following layer structure. Then, various evaluations were carried out. Layer structure: Rust preventive layer / Intermediate layer (LLDPE1) / Outer layer (LLDPE1) = 15 μm thick / 30 μm thick / 15 μm thick

[0070] [Examples 2 to 38, Comparative Examples 1 to 4] Masterbatches were selected according to the descriptions in Tables 2 to 9, and operated in the same manner as in Example 1 to produce a rust preventive film and evaluate it in the same manner.

[0071]

Table 2

[0072]

Table 3

[0073]

Table 4

[0074]

Table 5

[0075]

Table 6

[0076]

Table 7

[0077]

Table 8

[0078]

Table 9

[0079] <Evaluation method> [Film-forming property] The appearance of the rust-preventive film was observed with the naked eye, and the presence or absence of defects was evaluated according to the following evaluation criteria. ○: There were no wrinkles, bumps, peeling, etc. on the rust-preventive film. ×: There were wrinkles, bumps, peeling, etc. on the rust-preventive film.

[0080] [Heat-sealability] The rust-preventive film was cut into pieces of 100 mm × 100 mm. When there was an outer layer with heat-sealability, the outer layers were opposed to each other and overlapped. Then, using a heat-seal tester (manufactured by Tester Sangyo Co., Ltd.: TP-701-A), a 1 cm × 10 cm area was heat-sealed so that the ends were not heat-sealed and were bifurcated. Further, it was cut into strips with a width of 15 mm to prepare test pieces for measuring the heat-seal strength. Each bifurcated end of this test piece was attached to a tensile testing machine and pulled to peel the heat-sealed part, and the heat-seal strength (N / 15 mm width) was measured, and the pass / fail judgment was made according to the following pass / fail criteria. (Heat-seal conditions) Temperature: 160 °C Pressure: 1 kgf / cm 2 Time: 1 second (Tensile strength test conditions) Test speed: 300 mm / min Load range: 50 N (Acceptance criteria) ○: 30 N / 15 mm or more, Pass ×: Less than 30 N / 15 mm, Fail

[0081] [Rust prevention] The rust prevention film was cut into pieces of 100 mm × 100 mm. When there is an outer layer with heat sealability, the outer layers were opposed to each other, and after overlapping, a four-sided seal was performed on the laminate using an impulse sealer to produce a 100 mm × 100 mm pouch. Next, the following metal pieces were filled into the pouch 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) Iron plate: Cold rolled steel sheet (SPCC), 50 mm × 50 mm × 1 mm, degreased. Copper plate: Tough pitch copper plate (C1100P-1 / 4H), 50 mm × 50 mm × 1 mm, degreased. (Evaluation criteria) ◎: No rust and discoloration, or only spot rust and slight discoloration occur. 〇: Rust occurs in less than 10% of the area of the test piece. △: Rust occurs in 10% or more and less than 50% of the area of the test piece. ×: Rust occurs in 50% or more of the area of the test piece.

Explanation of symbols

[0082] 1 Rust prevention film 2 Rust prevention packaging material 3 Rust prevention layer 3a Rust preventive agent 4 Intermediate layer 5 Outer layer

Claims

1. A single-layer rust preventive film containing at least a rust preventive agent and a binder resin, wherein the rust preventive agent contains at least an alkali agent for neutralizing an acidic substance exhibiting alkalinity and one or more selected from the group consisting of fatty acids, metal fatty acids, and fatty acid esters (except when the rust preventive agent contains an alkyl dicarboxylic acid ammonium salt), the alkali agent contains one or more selected from the group consisting of alkali metal compounds and alkaline earth metal compounds, The alkali metal compound is Li 2 O, Na 2 O, K 2 O, LiCl, LiOH, and contains one or more selected from the group consisting of The alkaline earth metal compound contains one or more selected from the group consisting of BeO, SrO, BaO, RaO, Ca(OH) 2 and the carbon number of the fatty acid moiety of the fatty acid, metal fatty acid, and fatty acid ester is 6 or more and 20 or less, the fatty acid is selected from the group consisting of caproic acid, heptanoic acid, nonanoic acid, octanoic acid, decanoic acid, undecylic acid, lauric acid, stearic acid, nonadecylic acid, and arachidic acid, the metal fatty acid is selected from the group consisting of alkali metal salts or alkaline earth metal salts of the above fatty acids, the fatty acid ester is selected from the group consisting of alcohol esters of the above fatty acids and glycerin fatty acid esters, the rust preventive agent further contains an acidic gas adsorbent, and the acidic gas adsorbent contains one or more selected from the group consisting of hydrophobic zeolite, metal-supported zeolite, and amino group-supported porous body, the hydrophobic zeolite has a SiO2 / Al2O3 molar ratio of the constituent components of 30 / 1 to 10000 / 1, the metal species supported on the metal-supported zeolite is one or more selected from the group consisting of copper, zinc, silver, and platinum, a rust preventive film.

2. A multilayer rust preventive film having at least a rust preventive layer, wherein the rust preventive layer contains a rust preventive agent and a binder resin, the rust preventive agent contains at least an alkali agent for neutralizing an acidic substance exhibiting alkalinity and one or more selected from the group consisting of fatty acids, metal fatty acids, and fatty acid esters (except when the rust preventive agent contains an alkyl dicarboxylic acid ammonium salt), the alkali agent contains one or more selected from the group consisting of alkali metal compounds and alkaline earth metal compounds, The alkali metal compound is Li 2 O, Na 2 O, K 2 O, LiCl, LiOH, and contains one or more selected from the group consisting of The alkaline earth metal compound contains one or more selected from the group consisting of BeO, SrO, BaO, RaO, Ca(OH) 2 and is contained in an amount of one or more selected from the group consisting of the carbon number of the fatty acid moiety of the fatty acid, metal fatty acid, and fatty acid ester is 6 or more and 20 or less, The fatty acid is selected from the group consisting of caproic acid, heptanoic acid, nonanoic acid, octanoic acid, decanoic acid, undecylic acid, lauric acid, stearic acid, nonadecylic acid, and arachidic acid, The metal fatty acid is selected from the group consisting of alkali metal salts or alkaline earth metal salts of the above fatty acids, The fatty acid ester is selected from the group consisting of alcohol esters and glycerin fatty acid esters of the above fatty acids, The rust preventive further contains an acidic gas adsorbent, and the acidic gas adsorbent contains one or more selected from the group consisting of hydrophobic zeolite, metal-supported zeolite, and amino group-supported porous body, The hydrophobic zeolite has a SiO2 / Al2O3 molar ratio of the constituent components of 30 / 1 to 10000 / 1, The metal species supported on the metal-supported zeolite is one or more selected from the group consisting of copper, zinc, silver, and platinum, 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, characterized in that the rust preventive film is a coextruded film.

4. The rust preventive film according to claim 2 or 3, characterized in that the rust preventive film further has an intermediate layer.

5. The rust preventive film according to any one of claims 1 to 4, further containing an antioxidant, and the antioxidant contains a phenolic antioxidant and / or a phosphorus-based antioxidant.

6. A rust preventive packaging material, characterized in that it is made of the rust preventive film according to any one of claims 1 to 5.

7. A rust preventive package, characterized in that it is made of the rust preventive packaging material according to claim 6.

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