JP2019131267A - Rust prevention film for package made of metal material - Google Patents

Abstract

To provide a rust prevention film for a package made of a metal material which is superior to rust prevention performance regardless of using methods.SOLUTION: In a rust prevention film for a package made of a metal material having an inner layer and an outer layer, the inner layer and the outer layer include thermoplastic resin, and the inner layer has a specific quantity of nitrobenzoic acid and ammonium benzoate.SELECTED DRAWING: None

Description

  The present invention relates to a rust-proof film for packaging various metal materials, particularly various metal materials that require rust prevention.

  Conventionally, a rust-proof film for packaging and rust-proofing a metal material has been developed. For example, Patent Document 1 discloses a technique relating to a vaporizable rust-proof plastic film formed from a hot melt mixture in which a vaporizable rust preventive agent, a polyolefin resin, and a polar resin are uniformly mixed. Patent Document 2 discloses a technique related to a rust-proof film for metal packaging having a predetermined amount of a thermoplastic resin and a rust-preventive additive.

Japanese Patent Publication No. 47-4295 JP 2008-121070 A

  However, the rust preventive film for packaging metal materials described in Patent Documents 1 and 2 has insufficient rust preventive ability for metal materials depending on the method of use. Therefore, an object of the present invention is to provide a rust-proof film for packaging metal materials, which is superior in rust-proof ability, regardless of the method of use.

  As a result of repeated studies by the present inventors in order to solve the above problems, the first layer containing a specific amount of thermoplastic resin, nitrobenzoic acid, and ammonium benzoate, and the first layer are: In contrast, the present inventors have found that a rust preventive film for packaging metal materials having a second layer containing a thermoplastic resin and having the first layer as an inner layer can solve the above problems, and has completed the present invention.

That is, the present invention is a rust preventive film for packaging a metal material having an inner layer and an outer layer, wherein the inner layer and the outer layer include a thermoplastic resin, and the inner layer includes nitrobenzoic acid and ammonium benzoate. In an amount of 0.1 to 6.0 parts by mass with respect to 100 parts by mass of the resin component forming the inner layer, and in the inner layer, the nitrobenzoic acid and the ammonium benzoate It is a rust preventive film for packaging metal materials having a mass ratio of 1: 1 to 1: 2.
The outer layer contains sodium nitrite in an amount of 0.1 parts by mass or more and 4.0 parts by mass or less with respect to 100 parts by mass of the resin component forming the outer layer, and nitrobenzoic acid per unit volume of the inner layer. It is the said rust preventive film for metal material packaging whose ratio of the total mass of an acid and ammonium benzoate and the mass of the sodium nitrite per unit volume of the said outer layer is 8: 2 to 6: 4.

  According to the present invention, it is possible to provide a rust preventive film for packaging metal materials that is superior in rust preventive ability regardless of the method of use.

Hereinafter, the present invention will be described in more detail, but the present invention is not limited to specific embodiments.
The rustproof film for packaging metal materials according to the embodiment of the present invention has an inner layer and an outer layer.

The inner layer of the rust-proof film for packaging metal materials according to an embodiment of the present invention contains a thermoplastic resin.
Examples of the thermoplastic resin include homopolymer resins such as polyethylene, polypropylene, polyester resins, polyamide resins, polyolefin resins, polyacrylonitrile resins, and polystyrene resins; ethylene / vinyl acetate copolymers and ethylene / acrylic ester copolymers. Copolymer resins such as polymers; and the like. These thermoplastic resins may be used alone or in combination of two or more.
The inner layer may contain a resin other than the thermoplastic resin. The resin other than the thermoplastic resin may be a natural product or a synthetic product. Specific examples include resins such as polyvinyl alcohol. The weight average molecular weight of the resin is not particularly limited, but is usually in the range of 1,000 to 1,000,000, and preferably in the range of 10,000 to 200,000. In this specification, the weight average molecular weight of the resin is a value measured by gel permeation chromatography (GPC) and converted to polystyrene.

The inner layer of the rust-proof film for packaging a metal material according to an embodiment of the present invention is a layer disposed on the metal material side when the metal material is packaged.
The inner layer contains nitrobenzoic acid and ammonium benzoate in addition to the resin component. The content of nitrobenzoic acid and ammonium benzoate in the inner layer is 0.1 parts by mass or more and 6.0 parts by mass or less, respectively, with respect to 100 parts by mass of the resin component including the thermoplastic resin that forms the inner layer. Moreover, the mass ratio (A) of nitrobenzoic acid and ammonium benzoate in the inner layer is in the range of 1: 1 to 1: 2.
If the content of nitrobenzoic acid contained in the inner layer of the metal material packaging anticorrosion film is less than 0.1 parts by mass with respect to 100 parts by mass of the resin component forming the inner layer, the metal material of the anticorrosive film for metal material packaging If the rust-preventing effect on the resin becomes insufficient and exceeds 6.0 parts by mass, foaming occurs in the rust-preventive film for packaging metal materials, leading to a decrease in film properties such as a decrease in tensile strength and tear strength.
When the content of ammonium benzoate contained in the inner layer of the metal material packaging rust prevention film is less than 0.1 parts by mass with respect to 100 parts by mass of the resin component forming the inner layer, the metal material of the rust prevention film for metal material packaging Insufficient rust-preventing effect is produced, and if it exceeds 6.0 parts by mass, foaming occurs in the rust-preventing film for packaging metal materials, leading to a decrease in film properties such as a decrease in tensile strength and tear strength.
The rust preventive film for metal material packaging having a mass ratio (A) in the range of 1: 1 to 1: 2 can exhibit excellent rust preventive ability for the packaged metal material.
In addition, each ratio with respect to content (mass) of the resin component, nitrobenzoic acid, and ammonium benzoate in an inner layer is based on each ratio of the compounding mass concentration of each component in the resin composition which forms an inner layer.

Examples of the nitrobenzoic acid contained in the inner layer include o-nitrobenzoic acid, m-nitrobenzoic acid, and p-nitrobenzoic acid. These may be used alone or in combination of two or more. However, it is preferable to use p-nitrobenzoic acid because it is easy to produce a rust-proof film for packaging metal materials.
The rust preventive film for packaging metal material according to the embodiment of the present invention can exhibit excellent rust preventive ability for the packaged metal material by including an inner layer containing a specific amount of nitrobenzoic acid and ammonium benzoate.
The film thickness of the inner layer is not particularly limited, but is usually 1 μm or more, preferably 5 μm or more, and is usually 100 μm or less, preferably 50 μm or less.

The outer layer of the rust-proof film for packaging a metal material according to an embodiment of the present invention is a layer disposed outside the inner layer when viewed from the metal material when the metal material is packaged.
The outer layer includes a thermoplastic resin.
Examples of the thermoplastic resin include homopolymer resins such as polyethylene, polypropylene, polyester resins, polyamide resins, polyolefin resins, polyacrylonitrile resins, and polystyrene resins; ethylene / vinyl acetate copolymers and ethylene / acrylic ester copolymers. Copolymer resins such as polymers; and the like. These thermoplastic resins may be used alone or in combination of two or more.
The outer layer may contain a resin other than the thermoplastic resin. The resin other than the thermoplastic resin may be a natural product or a synthetic product. Specific examples include resins such as polyvinyl alcohol. The weight average molecular weight of the resin is not particularly limited, but is usually in the range of 1,000 to 1,000,000, and preferably in the range of 10,000 to 200,000.
The outer layer further includes sodium nitrite. The content of sodium nitrite is 0.1 parts by mass or more and 4.0 parts by mass or less with respect to 100 parts by mass of the resin component including the thermoplastic resin that forms the outer layer. The ratio (B) of the total mass of nitrobenzoic acid and ammonium benzoate per unit volume of the inner layer to the mass of sodium nitrite per unit volume of the outer layer is in the range of 8: 2 to 6: 4. Is within.
If the content of sodium nitrite contained in the outer layer of the metal material packaging rust prevention film is less than 0.1 parts by mass with respect to 100 parts by mass of the resin component forming the outer layer, the metal material of the rust prevention film for metal material packaging If the rust preventive effect on the metal is inadequate and exceeds 4.0 parts by mass, pinholes are likely to be generated in the rust preventive film for packaging metal materials, leading to a decrease in film properties such as a decrease in tensile strength and tear strength.
The rust-proof film for metal material packaging in which the ratio (B) is in the range of 8: 2 to 6: 4 can exhibit excellent rust-proof ability with respect to the packaged metal material.
In addition, the ratio with respect to content of the resin component and sodium nitrite in an outer layer is based on the ratio of the compounding mass concentration of each component in the resin composition which forms an outer layer.
The thickness of the outer layer is not particularly limited, but is usually 1 μm or more, preferably 5 μm or more, usually 100 μm or less, preferably 50 μm or less.

The rustproof film for packaging metal materials of the present embodiment may have an intermediate layer between the inner layer and the outer layer. The film may further have another layer on the outer side of the outer layer as viewed from the inner layer.
The intermediate layer and the other layer include a thermoplastic resin. Examples of the thermoplastic resin include homopolymer resins such as polyethylene, polypropylene, polyester resins, polyamide resins, polyolefin resins, polyacrylonitrile resins, and polystyrene resins; ethylene / vinyl acetate copolymers and ethylene / acrylic ester copolymers. Copolymer resins such as polymers; and the like. These thermoplastic resins may be used alone or in combination of two or more.

  The resin components in the inner layer, the outer layer, the intermediate layer and another layer of the rust-proof film for packaging metal material according to the embodiment of the present invention may be the same or different. Moreover, the film thicknesses in the inner layer, outer layer, intermediate layer, and another layer may be the same or different.

Each layer (an inner layer, an outer layer, an intermediate layer, another layer, etc.) of the rust-proof film for packaging a metal material according to an embodiment of the present invention may contain other components in addition to the above components. Examples of other components include components that improve the rust prevention ability of the packaged metal material. Specific examples include sodium tetraborate, powdered glass, sodium carbonate, sodium benzoate, 1,2,3-benzotriazole, sodium cinnamate, polyvinyl alcohol, ethyl cellulose, carboxymethyl cellulose sodium salt, and the like. These may be used alone or in combination of two or more. Examples of the combination of two or more components included in the inner layer include sodium benzoate and 1,2,3-benzotriazole. Examples of the combination of two or more components included in the outer layer include: Mention may be made of sodium carbonate and sodium carboxymethylcellulose. When each layer contains these components, the content of each component is usually 0.01 parts by mass or more, 0.1 parts by mass or more, and usually 5 parts by mass with respect to 100 parts by mass of the resin component forming each layer. It may be 3 parts by mass or less.

  Each layer of the rust-preventive film for packaging metal materials according to the embodiment of the present invention has an internal lubricant, an internal lubricant, You may further contain an external lubricant, an antiblocking agent, etc.

  The rustproof film for packaging metal materials according to the embodiment of the present invention can be produced by a known method. For example, it can be manufactured by a coextrusion multilayer molding method using each master batch in which a specified amount of components contained in each layer of the anticorrosion film is blended.

  The metal material to be packaged using the rust preventive film for packaging a metal material of the present invention may be a plate material, a foil material, or a molded product. The metal material is not particularly limited as long as it is a metal material that generates rust, and examples thereof include an aluminum material, a copper material, an iron material, a titanium material, or an alloy material thereof (for example, various SUS materials). it can. Further, on a base material such as a metal material, a ceramic material, or an organic material different from the metal material, for example, the above-described aluminum material, copper material, iron material, titanium material, or the like by a technique such as plating, vapor deposition, or cladding. A metal material such as an alloy material may be coated, or a composite material of the metal material and a material different from the metal material, such as a metal material, a ceramic material, or an organic material.

  The rust preventive film for packaging metal materials according to the embodiment of the present invention includes various metal materials in which rust is a concern and various metal products using various metal materials, in particular, automobile parts made of iron, steel, cast iron, precision It can be suitably used for transporting machine parts or various machine parts including copper and aluminum alloys to domestic and foreign countries and for storage in high-temperature and high-humidity atmospheres.

  Hereinafter, the rust preventive film for packaging a metal material according to the present invention will be described in detail using Examples and Comparative Examples. However, the present invention is not limited to these.

1. Production of Rust-Preventing Film for Packaging Metal Materials As shown in Table 1, a predetermined amount of components forming each layer of the film was blended to prepare each master batch. The films of Examples 1 to 7 and Comparative Example 1 were manufactured by laminating in order of the inner layer, the intermediate layer (or outer layer) and the outer layer (or outermost layer) by the coextrusion multilayer molding method using each master batch.

2. Contact rust test method (cycle wrapping method)
Next, as described below, a metal test piece was packaged with each film of Examples or Comparative Examples, and a contact rust prevention test (cycle wrapping method) was performed.
1) Test piece A commercially available cold-rolled steel sheet (JIS G 3141, SPCC-SD) (0.8 × 70 × 150 mm) was successively ultrasonically cleaned in white spirit (petrol) and methanol.
2) Manufacture of sample for contact rust prevention test Various films were cut into predetermined shapes (160 × 170 mm). Fold the film cut into a predetermined shape in half into a rectangular shape, sandwich the test piece inside the folded film, and heat seal three sides of the film to seal the test piece, and confine the test piece in the film Then, a sample for contact rust prevention test was manufactured.
3) Contact rust prevention test (immediately after film production)
A cycle in which a sample for contact rust prevention test is put into a constant temperature and humidity chamber and held for 6 hours under conditions of 50 ° C. and relative humidity of 95 RH%, and then held for 6 hours under conditions of 20 ° C. and relative humidity of 70 RH%. 40 cycles (initial rust prevention ability) or 60 cycles (long-term rust prevention ability) were performed. Thereafter, based on the JIS K 2246: 2007 6.4 rust generation degree measuring method, the effective surface of the central portion of the test piece was divided into a total of 100 squares by 10 squares in length and breadth, and the number of squares where rust was generated was measured. The test piece in which the number of squares in which rust was generated was “◎”, the test piece that was 1-10 squares was “◯”, the test piece that was 11-25 squares was “Δ”, 26 The test pieces that were larger than the square were evaluated as “x”. The results are shown in the column of “Contact Rust Test Results (immediately after film production)” in Table 1.
4) Contact rust prevention test (open storage 1 month later)
After various films were formed into sheets and stored in sheets for one month, a sample for contact rust prevention test was produced in the same manner as described in “2) Production of sample for contact rust prevention test”. . Thereafter, the contact rust test was carried out in the same manner as in “3) Contact rust test (immediately after film production)”, and the number of masses where rust was generated was measured and evaluated. The results are shown in the column of “Contact Rust Test Results (after 1 month of open storage)” in Table 1.

3. Gas phase rust prevention test method (box space method)
As will be described below, a metal test piece was packaged with each film of Examples or Comparative Examples, and a vapor phase rust prevention test (box space method) was performed.
1) Test piece In the same manner as the method described in “2. Contact rust prevention test method (cycle envelopment method)”, a cold-rolled steel plate (0.8 × 70 × 150 mm) was sequentially superposed in white spirit and methanol. What was sonic-cleaned was used.
2) Manufacture of sample for vapor phase rust prevention test Four acrylic resin plates having a thickness of 3 mm were cut out (113 × 270 mm) and assembled into a cylindrical shape using an adhesive to obtain a test box. After the test piece was placed in the test box, a vapor phase rust test sample was manufactured by sticking with an aluminum vapor deposited tape so that the open surface of the test box was sealed in two places with a film (150 × 150 mm). .
3) Gas phase rust prevention test (immediately after film production)
Samples for vapor-phase rust prevention test are put into a constant temperature and humidity chamber, and cycle test is conducted in the same way as “3) Contact rust prevention test (immediately after film production)” in “2. Then, the number of masses where rust was generated was measured and evaluated. The results are shown in the column of “Gas phase rust prevention test result (immediately after film production)” in Table 1.
4) Gas phase rust prevention test (after 1 month of open storage)
After various films were formed into sheets and stored in sheets for one month, samples for gas-phase rust prevention tests were produced in the same manner as in “2) Production of samples for gas-phase rust prevention tests”. . Then, after performing a vapor phase rust prevention test by the same method as “3) Vapor phase rust prevention test (immediately after film production), the number of masses where rust was generated was measured and evaluated. These results are shown in the column of “Gas phase rust prevention test result (after 1 month of open storage)” in Table 1.

Claims (2)

An anti-rust film for packaging metal materials having an inner layer and an outer layer,
The inner layer and the outer layer contain a thermoplastic resin, and the inner layer contains nitrobenzoic acid and ammonium benzoate in an amount of 0.1 parts by mass or more and 100 parts by mass with respect to 100 parts by mass of the resin component forming the inner layer. 0.0 parts by mass or less,
In the inner layer, a rust-proof film for packaging a metal material, wherein a mass ratio of the nitrobenzoic acid to the ammonium benzoate is 1: 1 to 1: 2. The outer layer contains sodium nitrite in an amount of 0.1 parts by mass or more and 4.0 parts by mass or less with respect to 100 parts by mass of the resin component forming the outer layer,
The ratio of the total mass of nitrobenzoic acid and ammonium benzoate per unit volume of the inner layer to the mass of sodium nitrite per unit volume of the outer layer is 8: 2 to 6: 4. A rust-proof film for packaging metal materials as described in 1.