JP7325040B2 - Method for producing volatile rust inhibitor and volatile rust inhibitor - Google Patents

Description

The present invention relates to a method for safely and satisfactorily producing a volatile rust inhibitor having a desired composition while suppressing volatilization of constituent components during production, and a volatile rust inhibitor produced by the method. .

When storing, transporting, or transporting iron and steel, various machine parts made of iron and steel, and equipment and parts made of metals that are easily oxidized, such as automobile parts, the surface will be oxidized and rusted. must be prevented.

Conventionally, as a rust prevention measure for metal members such as those described above, rust prevention oil is applied to the surface of the metal member to be rust-prevented to form an oil film, and oxygen and moisture that cause rust are removed. is a method of blocking However, in the method of using rust preventive oil, removing the oil film after use is complicated. Anti-rust agents have been put to practical use.

This type of volatile solid rust inhibitor is generally called VCI (Volatile Corrosion Inhibitor), and a typical example is sublimable cyclohexylamine carbonate (CHC) [(C ₆ H ₁₁ NH ₃ )CO ₂ (C ₆ H ₁₁ NH)], diisopropylamine nitrite (DIPAN) [(iPro) ₂ NH.HNO ₂ ], dicyclohexylamine nitrite (DICHAN) [(C ₆ H ₁₁ ) ₂ NH.HNO ₂ ]. etc. are known.

However, although CHC exhibits excellent initial rust prevention ability, it has a strong odor and its vapor pressure is as high as 4×10 ⁻¹ mmHg (25° C.). must do. On the other hand, DICHAN has excellent long-term rust prevention ability, but its vapor pressure is as low as 1×10 ^-4 mmHg (25°C), and it takes 20 hours or more to exert its rust prevention effect. Lack. Further, if the distance from the object to be rust-proofed is 20 to 30 cm or more, a sufficient rust-proofing effect cannot be exhibited. Moreover, the vapor pressure of DIPAN is 5×10 ⁻³ mmHg (25° C.), which is between CHC and DICHAN. , part of which is known to degenerate to produce diisopropyl-N-nitrosamine, which has been pointed out to be carcinogenic, and whose use is repelled from a health standpoint. tend to be

Therefore, the present applicant has proposed a volatile rust inhibitor containing nitrite, ammonium salt, hydrogen carbonate metal salt, and an auxiliary agent as a volatile rust inhibitor having excellent initial rust prevention ability, long-term rust prevention ability, and long-distance effective reachability. A rust agent was developed (Patent Document 1). In particular, a volatile rust inhibitor containing a nitrous acid metal salt and an organic acid ammonium salt produces ammonium nitrite that has a high vapor pressure at room temperature and is excellent in rust prevention effect.

Patent Document 2 also discloses a two-component rust inhibitor in which a mixture [A] containing a water-soluble resin and a nitrite salt and a mixture [B] containing a thermoplastic resin, ammonium benzoate, etc. coexist. Dispersion coating of the surface layer of [B] with an aqueous solution of the mixture [A] is also described.

Patent Document 3 discloses a sheet-like packaging material formed by molding a water-insoluble thermoplastic resin, a water-soluble thermoplastic resin, and a hygroscopic resin containing a deliquescent salt, and a water-insoluble thermoplastic resin is coated on one side thereof. It also describes forming a protective resin layer comprising chisel or a water-insoluble thermoplastic resin and a water-soluble thermoplastic resin, and that the protective resin layer contains a rust inhibitor such as ammonium benzoate.

Patent Literature 4 describes an antirust composition containing a polymer consisting only of a water-soluble resin, a vaporizable compound such as ammonium benzoate, a buffering compound, a deliquescent compound, and the like.

However, when, for example, a nitrite and an ammonium compound are melt-kneaded in a resin, they may react violently at high temperatures to generate gas, resulting in foaming of the molded article. Therefore, the rust-preventive multilayer film described in Patent Document 5 is composed of a polyolefin resin layer containing a nitrite and a polyolefin resin layer containing an ammonium compound or the like.

JP-A-2001-31966 JP-A-10-158645 JP 2015-123378 A JP-A-2016-89208 JP-A-1-210340

As described above, various volatile rust inhibitors have been developed, and rust-preventive multi-layer films have also been developed in which rust-preventive components that readily react with each other are separated into layers.
However, the present inventors have found that even if the antirust film is composed of multiple layers, some of the antirust components volatilize when the resin is melted and molded, which poses a safety problem during production. In addition to that, it was found that a volatile rust inhibitor with a desired composition could not be obtained, and as a result, sufficient rust prevention performance could not be obtained.
Accordingly, the present invention provides a method for safely and satisfactorily producing a volatile rust inhibitor having a desired composition while suppressing volatilization of constituent components during production, and a volatile rust inhibitor produced by the method. The challenge is to

The present inventors have made intensive studies to solve the above problems. As a result, we found that by using an aqueous solution containing a volatile amine/ammonium rust inhibitor and a water-soluble resin, it is possible to form a rust preventive film safely and satisfactorily while suppressing volatilization of the amine/ammonium rust inhibitor. , completed the present invention.
The present invention is shown below.

[1] A method for producing a volatile rust inhibitor, comprising:
a step of molding a composition containing a nitrite metal salt and a resin to produce a molded body;
a step of applying a coating liquid containing an amine/ammonium rust inhibitor, a water-soluble resin and water to at least a portion of the molded body;
A method, comprising the step of drying the coating liquid and forming an antirust coating containing an amine/ammonium antirust agent on at least part of the surface of the molded body.
[2] The method according to [1] above, wherein the coating liquid is dried at 50°C or lower.
[3] The method according to [1] or [2] above, wherein the nitrite metal salt is an alkali metal salt and/or a group 2 metal salt of nitrite.
[4] Any of the above [1] to [3], wherein the amine/ammonium rust inhibitor is an organic acid ammonium salt, an organic acid amine salt, an inorganic acid ammonium salt, an inorganic acid amine salt, and/or an organic amine. The method described in Crab.
[5] The method according to any one of the above [1] to [4], wherein the composition and/or the antirust coating further contain an organic antirust agent.
[6] The method according to any one of [1] to [5] above, wherein the molded article is in the form of a film.
[7] Having a compact and an antirust coating,
The rust preventive film covers at least a part of the compact,
The molded article contains a nitrite metal salt and a resin, and
A volatile rust inhibitor, wherein the rust preventive film contains an amine/ammonium rust inhibitor and a water-soluble resin.
[8] The volatile rust inhibitor according to [7] above, wherein the nitrite metal salt is an alkali metal salt and/or a group 2 metal salt of nitrite.
[9] The above [7] or [8], wherein the amine/ammonium rust inhibitor is an organic acid ammonium salt, an organic acid amine salt, an inorganic acid ammonium salt, an inorganic acid amine salt, and/or an organic amine. volatile rust inhibitor.
[10] The volatile rust inhibitor according to any one of the above [7] to [9], wherein the composition and/or the rust preventive film further contains an organic rust inhibitor.
[11] The volatile rust inhibitor according to any one of [7] to [10], wherein the molded product is in the form of a film.

According to the method of the present invention, it is possible to safely form a rust preventive film while suppressing volatilization of a volatile amine/ammonium rust preventive agent, and to produce a volatile rust preventive agent having a desired composition. . In addition, although it is not necessarily clear, in the volatile rust preventive agent produced by the method of the present invention, since it is a water-soluble resin, the moisture contained in the rust preventive film probably causes metal nitrite to form at the interface between the compact and the rust preventive film. It is believed that the salt reacts with the amine/ammonium rust preventive agent to form a vaporizable amine/ammonium nitrite salt, effectively exhibiting the rust preventive performance. In fact, as shown in the examples below, the rust preventive performance of the volatile rust inhibitor produced by the method of the present invention is extremely excellent.
Therefore, the present invention is industrially useful as a technique for safely producing a volatile rust inhibitor that can effectively suppress the rusting of metal products.

FIG. 1 is a photograph of a metal test piece subjected to an antirust performance test of a two-layer antirust film according to the present invention. FIG. 2 is a photograph of a metal specimen subjected to an antirust performance test without using an antirust agent. FIG. 3 is a photograph of a metal test piece subjected to an antirust performance test of a single-layer antirust polyethylene film containing an antirust agent. FIG. 4 is a photograph of a metal test piece subjected to an antirust performance test of a polyethylene film having an antirust coating. FIG. 5 shows the results of metal specimens subjected to the antirust performance test of the two-layer antirust polyethylene film.

Hereinafter, the method for producing the volatile rust inhibitor according to the present invention will be described step by step, but the present invention is not limited to the following specific examples.

Molded Body Production Step In this step, a molded body is produced by molding a composition containing a nitrite metal salt and a resin.

Nitrite metal salts not only exhibit rust-preventive action per se, but in the present invention react with amine/ammonium rust inhibitors to form volatile amine/ammonium nitrite salts, further preventing rust. Effective.

Nitrite metal salts are not particularly limited, but examples include alkali metal salts such as lithium salts, sodium salts and potassium salts; Group 2 metal salts such as calcium salts and magnesium salts. Only one kind of metal nitrite may be used alone, or two or more kinds thereof may be used in combination.

The amount of the nitrite metal salt used may be adjusted as appropriate. For example, when the antirust component in the molded article is the nitrite metal salt alone, the ratio of the nitrite to the entire molded article is 0.5% by mass or more. , 5% by mass or less, and when an antirust component other than the nitrite metal salt is blended in the molded body, the ratio of the nitrite to the entire molded body can be 0.05% by mass or more and 2% by mass or less. .

Since the essential metal nitrite salt in the composition and molded article has excellent heat resistance, the resin constituting the composition and molded article is not particularly limited. For example, polyolefin resins such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and polypropylene; polystyrene resins; polyester resins such as polyethylene terephthalate and polybutylene terephthalate; polyamide resins such as nylon 6 and nylon 12; Water-soluble resins such as polyvinyl alcohol and polyacrylic acid resins; and copolymer resins such as ethylene-vinyl acetate, ethylene-propylene, ethylene-butene and ethylene-acrylic acid esters. Only one resin may be used alone, or two or more resins may be used in combination.

The amount of the resin to be used may be appropriately adjusted within a range in which the molded article can be produced appropriately. For example, the ratio of the resin to the entire molded body can be 80% by mass or more and 99.95% by mass or less.

The molded article may contain an antirust component other than the nitrite metal salt. Such antirust components include organic antirust agents. The organic antirust agent here is an antirust component having relatively excellent heat resistance, and is different from the amine/ammonium antirust component described later. That is, the organic antirust agent does not have an ammonium cation and an amino group, and is a rust preventive component that is relatively excellent in heat resistance. Examples of such organic rust inhibitors include benzotriazole rust inhibitors such as benzotriazole, methylbenzotriazole, and dimethylbenzotriazole; Pyrazolone-based rust inhibitors such as phenyl-3-methyl-5-pyrazolone; 5-dicarboxylic acid, imidazole rust inhibitors such as 2-mercaptobenzimidazole; polycarboxylic acids such as sebacic acid, dodecanedioic acid, adipic acid, fumaric acid, succinic acid, citric acid, tartaric acid, malic acid, and salts thereof system rust inhibitors. Examples of the counter cation of the polycarboxylic acid antirust agent include alkali metal ions such as lithium ions, sodium ions and potassium ions, and Group 2 metal ions such as calcium ions and magnesium ions.

Only one kind of the organic rust inhibitor may be used alone, or two or more kinds thereof may be used in combination. The amount of the organic antirust agent to be used may be appropriately adjusted within a range in which the antirust effect is appropriately exhibited. For example, the ratio of the organic rust preventive agent to the entire molded body can be 0.05% by mass or more and 2% by mass or less.

In addition to the antirust agent and the resin, other additives may be added to the molding. Examples of additives include lubricants, fillers, plasticizers, antioxidants, ultraviolet absorbers, light stabilizers, antistatic agents, flame retardants, colorants, and antifungal agents.

Lubricants include, for example, silica, alumina, and talc. Examples of fillers include inorganic fillers such as calcium carbonate, titanium oxide, silica, and carbon black. Examples of plasticizers include phthalates, aromatic dibasic acid esters, process oils, fatty acid oils, aromatic esters, fatty acid esters, phosphates, sulfonates, and sulfonamides. Examples of antioxidants include phenol antioxidants, aromatic amine antioxidants, sulfur antioxidants, phosphoric acid antioxidants, and the like. Examples of ultraviolet absorbers include benzotriazole-based ultraviolet absorbers, salicylate-based ultraviolet absorbers, benzoate-based ultraviolet absorbers, and benzophenone-based ultraviolet absorbers. Examples of light stabilizers include hindered amine light stabilizers, phenol light stabilizers, and nickel light stabilizers. Examples of antistatic agents include fatty acid esters and polyalkylene glycol esters. Phosphate ester etc. are mentioned as a flame retardant. Examples of colorants include organic pigments, organic dyes, inorganic pigments, and inorganic dyes. Examples of antifungal agents include organic sulfur antifungal agents, organic nitrogen sulfur antifungal agents, and organic halogen antifungal agents.

The amount of the additive to be used may be appropriately adjusted within a range in which the effect is appropriately exhibited. For example, the proportion of the additive with respect to the entire molded body can be 0.05% by mass or more and 2.5% by mass or less.

Since the nitrite metal salt, which is an essential rust preventive component in the molded article, has excellent heat resistance, the molded article may be formed into a desired shape by ordinary melt molding. For example, solid components other than resin are mixed and finely pulverized to, for example, 100 μm or less. It is then melt-mixed with part of the resin to produce a masterbatch. Next, the masterbatch and the resin are melt-mixed and molded into a desired shape.

The shape of the molded article is not particularly limited. For example, it can be in the form of a film for packaging iron and steel materials, iron and steel parts, and iron and steel products, and can be a rust prevention film packed together with iron and steel materials in packaging. The thickness of these films may be appropriately adjusted, and may be, for example, 20 μm or more and 2 mm or less.

Alternatively, a relatively thick sheet may be used as a container for storing steel parts or the like. A film and a sheet are not particularly clearly distinguished, but the thickness of the sheet can be, for example, 1 mm or more and 5 mm or less. In addition, the molded body may be molded together with a foaming agent and used as a cushioning material that is packed together with steel material or the like in a package.

Step of Applying Coating Liquid In this step, a coating liquid containing an amine/ammonium rust inhibitor, a water-soluble resin, and water is applied to at least a part of the surface of the molded body.

Amine/ammonium rust preventives are ammonium salts and amine salts of organic and inorganic acids, and organic compounds having an amino group, which exhibit rust preventive action. Examples of such amine/ammonium rust inhibitors include organic acid ammonium salts such as ammonium benzoate, ammonium phthalate, ammonium sebacate, ammonium stearate, ammonium palmitate, ammonium oleate, and ammonium adipate; ammonium phosphate; , inorganic acid ammonium salts such as ammonium carbonate; amine salts of organic acids such as dicyclohexylamine benzoate, cyclohexylamine benzoate, dicyclohexylamine caprate, cyclohexylamine laurate; inorganic acids such as dicyclohexylamine phosphate amine salts of; hexamethylenetetramine, urea, thiourea, 2-amino-2-methyl-1-propanol, 2-aminoethanol, 2-methylaminoethanol, 1-amino-2-propanol, 3-methoxypropylamine, Organic amines such as 2-(dimethylamino)ethanol, 2-(diethylamino)ethanol, diisopropylamine, cyclohexylamine, dicyclohexylamine, N-ethylmorpholine and N-methylmorpholine are included. Although urea and thiourea cannot generally be called organic amines, they are included in organic amines for the sake of convenience in the present disclosure.

As the amine/ammonium rust inhibitor, a water-soluble or hydrophilic one is preferable so that the coating liquid can be well prepared. The amine/ammonium rust preventives may be used singly or in combination of two or more.

The amount of the amine/ammonium rust preventive used may be appropriately adjusted within the range in which the rust preventive effect is effectively exhibited. Above, it can be below 5 mass %.

The water-soluble resin forms the matrix of the anticorrosive film, and since it is water-soluble, it can be dissolved or dispersed in water to form a coating liquid. Furthermore, water molecules may be present in the antirust coating from the beginning due to the action of the water-soluble resin, or moisture in the atmosphere may be adsorbed or absorbed by the antirust coating. It is believed that water molecules in this rust preventive film contribute to the formation of volatile rust preventives, that is, amine salts or ammonium salts of nitrous acid through reaction between nitrite metal salts and amine/ammonium rust preventives.

Water-soluble resins include not only those that are completely soluble in water, but also those that are hydrophilic and can be dispersed well in water. Examples of water-soluble resins include acrylic resins, urethane resins, phenol resins, epoxy resins, alkyd resins, silicone resins, vinyl acetate resins, polyvinyl alcohol, polyethylene glycol, polyethylene oxide, carboxymethylcellulose, and polyvinylpyrrolidone.

Only one kind of water-soluble resin may be used alone, or two or more kinds thereof may be used in combination. The amount of the water-soluble resin to be used may be appropriately adjusted within a range in which the antirust film is formed satisfactorily. can be

In addition to the amine/ammonium rust inhibitor and the water-soluble resin, the coating liquid may contain additives that are commonly used in coating liquids. Additives include, for example, viscosity modifiers.

The viscosity improver is not particularly limited as long as it is water-soluble and can moderately adjust the viscosity of the coating solution. Examples include xanthan gum, pullulan, gelatin, agar, locust bean gum, pectin, and tamarind gum. , guar gum, modified sodium polyacrylate, urethane-modified polyether, and the like.

A viscosity improver may be used individually by 1 type, and may use 2 or more types together. The amount of the viscosity improver used depends on the desired thickness of the antirust coating, but should be, for example, 0.1% by mass or more and 10% by mass or less with respect to the antirust coating formed on the compact. can be done. In addition, the viscosity of the coating liquid is, for example, 100 mPa s or more and 2,000 mPa s or less when the desired thickness of the rust preventive film is relatively thin, and When thick, it can be over 2,000 mPa·s and up to 10,000 mPa·s.

A surfactant may be added to the coating liquid. The surfactant improves the leveling property of the coating liquid. Further, for example, when the molded body is porous, it is possible to sufficiently fill the pores with the coating liquid. Surfactants also have the effect of improving the solubility and dispersibility of constituents in solvents.

As the surfactant, nonionic surfactants, anionic surfactants, cationic surfactants and amphoteric surfactants can be used without particular limitation, but nonionic surfactants are preferred. Nonionic surfactants are not particularly limited, but examples include polyoxyethylene alkyl ethers, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol fatty acid esters, glycerin fatty acid esters, polyoxyethylene fatty acid esters, polyoxyethylene curing Castor oil, polyoxyethylene alkylamine, silicone-based surfactants, and the like.

In addition, the coating liquid may contain the organic rust preventive agent and other additives exemplified as components to be added to the compact. Specific examples and compounding amounts of the organic antirust agents and additives are based on the above description.

Water is used as a solvent for the coating liquid. However, a water-miscible organic solvent may be used in combination for dissolving or dispersing the amine/ammonium rust inhibitor and the water-soluble resin. A water-miscible organic solvent refers to an organic solvent that is infinitely miscible with water, and examples thereof include lower alcohols such as methanol, ethanol, and isopropanol; and glycols such as ethylene glycol and propylene glycol. When a mixed solvent of water and a water-miscible organic solvent is used as the solvent, the ratio of the water-miscible organic solvent in the entire mixed solvent can be 0.5% by mass or more and 20% by mass or less, and 10% by mass or less. Or 5 mass % or less is preferable, and 2 mass % or less or 1 mass % or less is more preferable.

The solvent is used to the extent that it can sufficiently dissolve or disperse the antirust coating components. For example, the ratio of the solvent to the entire coating liquid can be about 35% by mass or more and 65% by mass or less.

The coating liquid may be prepared by adding an amine/ammonium antirust agent, a water-soluble resin, and other additives to a solvent and thoroughly mixing them. If the respective components are not sufficiently dissolved or dispersed, they may be heated to about 40° C. or higher and 80° C. or lower, or ultrasonic waves may be applied. At this stage, since the coating liquid contains a sufficient amount of solvent, volatilization of the amine/ammonium rust preventive agent is suppressed even if the temperature is relatively high.

The obtained coating liquid is applied to at least part of the surface of the molded body. For example, in the case of a film for packaging steel parts or the like or a container for housing steel parts, it is preferable to coat the inner surface of the steel parts to be rust-proof. The coating amount may be adjusted according to the desired thickness of the antirust coating to be formed.

Drying step In this step, the coating liquid applied to at least part of the surface of the molded article is dried to form a rust preventive film containing an amine/ammonium rust inhibitor on at least a part of the surface of the molded article. do. Melt molding of thermoplastic resins is usually performed at a temperature of over 100 degrees Celsius, so there is a risk that the volatile rust preventive component will volatilize. Excessive high temperature is not necessary because it is only necessary to distill off the solvent such as

The temperature for drying is not particularly limited as long as the solvent can be distilled off while suppressing volatilization of the amine/ammonium rust preventive agent. Since the main solvent contained in the coating liquid is water, it can be dried at 20° C. or higher. Moreover, if the drying temperature is 50° C. or less, volatilization of the rust preventive component can be sufficiently suppressed. The temperature is more preferably 40° C. or lower, and even more preferably 30° C. or lower. This step may be carried out under reduced pressure mainly to keep the drying temperature low, but may be carried out at normal pressure for productivity. Moreover, you may perform drying at normal temperature. The drying time is not particularly limited, and may be dried until the coating liquid is sufficiently dried to form an anticorrosive film.

The volatile rust preventive agent according to the present invention has a molded body and a rust preventive film, the rust preventive film covers at least a part of the molded body, and the molded body contains a nitrite metal salt and a resin. and the anticorrosive film contains an amine/ammonium antirust agent and a water-soluble resin. As described above, the volatile rust preventive agent of the present invention can be produced safely and satisfactorily while suppressing volatilization of volatile rust preventive components. In addition, due to the water-soluble resin forming the antirust coating, moisture is present in the antirust coating from the beginning, or moisture in the atmosphere can be adsorbed or absorbed. Due to this moisture, the nitrite metal salt and the amine/ammonium rust inhibitor gradually react at the interface between the molded article and the rust preventive film, producing volatile amine/ammonium nitrite salt, which provides long-term protection. It is considered that the rust performance is effectively exhibited.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited by the following examples, and can be modified appropriately within the scope that can conform to the gist of the above and later descriptions. It is of course possible to implement them, and all of them are included in the technical scope of the present invention.

Example 1: Two-layer anticorrosive film (1) Preparation of single-layer anticorrosive film 30% by mass of sodium nitrite, 15% by mass of disodium sebacate, 15% by mass of benzotriazole, and 40% by mass of talc are mixed to obtain The resulting mixture was pulverized by a pulverizer to a size of 100 μm or less to obtain a rust inhibitor powder. 30 parts by mass of this rust inhibitor powder and 70 parts by mass of low-density polyethylene (“Petrothene ^(R) 249” manufactured by Tosoh Corporation, density: 0.916 kg/m ³ , MFR: 70 g/10 min) were uniformly mixed, and 120 parts by mass were mixed. A strand molded by an extruder at °C was cut by a pelletizer to prepare a rust inhibitor masterbatch.
5 parts by mass of the rust inhibitor masterbatch and 95 parts by mass of low-density polyethylene (“Petrothene ^(R) 180” manufactured by Tosoh Corporation, density: 0.922 kg/m ³ , MFR: 2.0 g/10 min) are uniformly mixed. Then, a single-layer antirust film A having a thickness of 100 µm was produced by an inflation molding machine at 140°C.

(2) Preparation of anticorrosive coating liquid 1% by mass of ammonium benzoate, acrylic copolymer emulsion ("Banstar X1658B" manufactured by Chubu Saiden Co., Ltd., non-volatile content: 46.0% by mass, Tg: 7 ° C., MFT: 12 ° C. ) and 3 parts by mass of a water-based viscosity improver (“SN Thickener A-818” manufactured by San Nopco Co., Ltd.) were uniformly mixed and dissolved to obtain a rust preventive coating solution B.

(3) Preparation of two-layer anticorrosive film Single-layer anticorrosive film A obtained in (1) above was cut into a size of 250 mm x 400 mm, and 2 to 6 g was weighed out with an electronic balance, coated uniformly on the antirust film using a SUS pipe of 5 mm in diameter and 500 mm in length, and dried at room temperature overnight. In the obtained two-layer anticorrosive film, the dry film amount of the anticorrosive coating solution B was about 30 g/m ² .

Comparative Example 1: Polyethylene Film A 100 μm thick polyethylene film containing no antirust agent was produced from low-density polyethylene (“Petrothene ^(R) 249” manufactured by Tosoh Corporation) in the same manner as in Example 1 (1).

Comparative Example 2: Single-layer antirust film The single-layer antirust film prepared in Example 1 (1) was used as it was.

Comparative Example 3: Polyethylene Film Having Antirust Coating A dry coating of 30 g/m ² of antirust coating solution B was formed on the polyethylene film of Comparative Example 1 in the same manner as in Example 1 (3).

Comparative Example 4: Two-layer Antirust Film 50% by mass of ammonium benzoate and 50% by mass of talc were mixed, and the resulting mixture was pulverized to 100 μm or less with a pulverizer to obtain a rust inhibitor powder. 20 parts by mass of this rust inhibitor powder and 80 parts by mass of low-density polyethylene (“Petrothene ^(R) 249” manufactured by Tosoh Corporation, density: 0.916 kg/m ³ , MFR: 70 g/10 min) were uniformly mixed, A strand molded by an extruder at °C was cut by a pelletizer to prepare a rust inhibitor masterbatch.
5 parts by mass of the rust inhibitor masterbatch and 5 parts by mass of the rust inhibitor masterbatch obtained in Example 1 (1) were each mixed with low-density polyethylene (“Petrothene ^(R) 180” manufactured by Tosoh Corporation, density: 0.922 kg/ 95 parts by mass of m ³ , MFR: 2.0 g/10 min) are uniformly mixed and formed into separate layers by a two-layer inflation molding machine at 140° C. so that each layer has a thickness of 50 μm. A two-layer antirust film having a thickness of 100 μm was produced.

Test Example 1: Rust Prevention Test The rust prevention performance of each film of Example 1 and Comparative Examples 1 to 4 was tested according to JIS Z1542 6.3 "Testing method for volatile rust resistance". The outline of the test conditions is described below. A 1000 mL wide-mouth stoppered bottle was washed with 2-propanol. A hole with a diameter of 16 mm is made in the center of a silicone rubber stopper that can plug the mouth of a wide-mouthed common stopper bottle, and an aluminum tube with an outer diameter of 16 mm, a wall thickness of 1.6 mm, and a length of 114 mm specified in JIS H4080. is passed through the hole in the rubber plug so that both ends are the same length, a rubber tube is attached to the bottom side for heat insulation, and a hole of 13 mm in diameter is opened in the center, and the rubber plug is turned upside down. It was installed leaving 9.5 mm on the bottom side. A JIS G3108 SGD3 carbon steel test piece with a diameter of 16 mm and a length of 13 mm was drilled at one end with a diameter of 9.5 mm and a depth of 9.5 mm. A carbon steel test piece was inserted from the upper bottom side of the rubber plug until the holed side touched the aluminum tube. In order to adjust the relative humidity in the wide-mouthed stoppered bottle to 90 to 95%, add 30% by weight glycerin aqueous solution (10 mL), cut each film into strips of 25 mm × 150 mm, and cut 6 sheets per bottle. Adhesive tape was attached to the sides of the rubber stopper so as not to overlap each other, and the wide-mouthed stoppered bottle was capped.
Place the wide-mouthed common stopper bottle in a constant temperature bath maintained at 24 ° C ± 2 ° C, remove it from the constant temperature bath after 20 hours, fill the aluminum tube with ice water with enough ice so that dew condensation occurs on the test piece surface, and again at a constant temperature placed in the tank. After 3 hours the water was removed. The above operation was performed for each film in three cases. The amount of rust generated on one side of the test piece was counted with the naked eye and with a magnifying glass, and the test piece side was photographed, and the photograph was enlarged so that the evaluation surface was a circle with a diameter of 160 mm, to obtain the rust prevention rate. In addition, in JIS Z1542, if the number of rust is 1 or more by naked eye observation, observation with a magnifying glass is not required, and if the rust count is grade 3 or higher, the rust prevention rate is calculated. is not required. Table 1 shows the evaluation criteria shown in JIS Z1542, and Table 2 shows the evaluation results.

1 to 5 show photographs of test pieces immediately after the test. In FIGS. 3 and 5, circles (◯) indicate the positions of rust observed with the naked eye.
As the results shown in Table 2 and FIGS. 1 and 3 show, under the test conditions for the JIS Z1542 evaporation-strengthened type, a rust-preventive film was formed on the polyethylene film as well as Comparative Example 1 in which no rust-preventive agent was used. Clear rust occurred in Comparative Example 3 as well.
In Comparative Example 2, which is a single-layer antirust film, rust occurred although it was suppressed.
When the film of Comparative Example 4, which has a two-layer structure consisting of a polyethylene film containing sodium nitrite and a polyethylene film containing ammonium benzoate, was used, rust was considerably suppressed, but rust was visible with the naked eye.
On the other hand, in Example 1 using the two-layer anticorrosive film of the present invention, no rust was observed with the naked eye, and only one rust was observed in each case by magnified observation.
In Comparative Example 4, which has a two-layer structure with the same antirust agent composition, a slight amount of rust was observed because the matrix resin of each layer was polyethylene and the film was formed at 140 ° C. part of the ammonium benzoate has volatilized, or because the hydrophobic polyethylene film contains no or very low water content, the film does not absorb moisture during the test, so nitrous acid It is believed that the reaction between sodium and ammonium benzoate did not proceed.
On the other hand, in the two-layer antirust film of Example 1, the layer containing ammonium benzoate was composed of acrylic resin, which is a water-soluble resin, and the drying was performed at room temperature, so ammonium benzoate was volatilized. In addition, the layer contained moisture and absorbed moisture during the test.
Therefore, it is expected that the difference in rust preventive performance between the two-layer anticorrosive films of Example 1 and Comparative Example 4 will further increase as the test time increases.

Claims (11)

A method for producing a volatile rust inhibitor, comprising:
a step of molding a composition containing a nitrite metal salt and a resin to produce a molded body;
resins selected from amine/ammonium rust inhibitors, acrylic resins, urethane resins, phenolic resins, epoxy resins, alkyd resins, silicone resins, vinyl acetate resins, polyvinyl alcohol, polyethylene glycol, polyethylene oxide, carboxymethylcellulose and polyvinylpyrrolidone ; And a step of applying a coating liquid containing water to at least a part of the molded body, and
A method, comprising the step of drying the coating liquid and forming an antirust coating containing an amine/ammonium antirust agent on at least part of the surface of the molded body. The method according to claim 1, wherein the coating liquid is dried at 50°C or less. 3. The method according to claim 1 or 2, wherein the nitrite metal salt is an alkali metal salt and/or a group 2 metal salt of nitrite. The method according to any one of claims 1 to 3, wherein the amine/ammonium rust inhibitor is an organic acid ammonium salt, an organic acid amine salt, an inorganic acid ammonium salt, an inorganic acid amine salt, and/or an organic amine. 5. The method according to any one of claims 1 to 4, wherein the composition and/or the antirust coating further contain an organic antirust agent. 6. The method according to any one of claims 1 to 5, wherein the molded article is in the form of a film. It has a molded body and an anti-corrosion film,
The rust preventive film covers at least a part of the compact,
The molded article contains a nitrite metal salt and a resin, and
The anticorrosive film is an amine/ammonium antirust agent, and acrylic resin, urethane resin, phenol resin, epoxy resin, alkyd resin, silicone resin, vinyl acetate resin, polyvinyl alcohol, polyethylene glycol, polyethylene oxide, carboxymethyl cellulose and polyvinyl. A volatile rust inhibitor characterized by containing a resin selected from pyrrolidones . 8. The volatile rust inhibitor according to claim 7, wherein the nitrite metal salt is an alkali metal salt and/or a group 2 metal salt of nitrite. 9. The volatile rust inhibitor according to claim 7, wherein the amine/ammonium rust inhibitor is an organic acid ammonium salt, an organic acid amine salt, an inorganic acid ammonium salt, an inorganic acid amine salt, and/or an organic amine. . The volatile rust inhibitor according to any one of claims 7 to 9, wherein the molded article and/or the rust preventive film further contain an organic rust inhibitor. The volatile rust inhibitor according to any one of claims 7 to 10, wherein the molded article is in the form of a film.