JPS6257714B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD This invention relates to metal corrosion inhibitors. More specifically, it can suppress corrosion of various metals in aqueous media, such as ferrous metals such as steel, mild steel, and cast iron, copper metals such as copper and brass, and aluminum metals, and can be used in cooling water systems, boiler water systems, etc. This invention relates to suitable metal corrosion inhibitors. Conventionally, systems in which an aqueous medium is introduced or passed through, such as various cooling systems and heat exchange systems in petrochemicals, synthetic chemicals, food chemicals, steel manufacturing, paper manufacturing, textile factories, etc., diesel engines,
It is desired to prevent corrosion of various metals used in cooling systems such as radiators of automobiles, etc., and various anticorrosive agents have been proposed. Such anticorrosive agents include those mainly containing heavy metal ions such as chromium and zinc, and anionic components such as phosphoric acid, polymerized phosphoric acid, phosphonic acid, molybdic acid, tungstic acid, aliphatic oxycarboxylic acids, and polyphenols. Various materials have been proposed, including those mainly composed of cationic components such as amine compounds, those mainly composed of cationic components such as amine compounds, and those containing these in combination. However, the above-mentioned heavy metal ions such as chromium and zinc have problems in terms of pollution, and in particular, chromium-based compounds are currently hardly used due to their toxicity. In this regard, the inventors of the present invention first focused on the use of zirconium, which has particularly low toxicity among heavy metals, as an active ingredient in anticorrosive agents. Zirconium is originally known as a heavy metal with low toxicity (J. Schubert. Science 105.389-390
(1947) and J. Nutr. 95.95-101 (1968), etc.). It is known that such zirconium can be used as part of the active ingredient in the field of so-called rust inhibitors, which prevent corrosion by applying a preparation with an appropriate viscosity to metal surfaces (Tokuko Sho et al.
(See Japanese Patent Publication No. 39-29946 and Japanese Patent Publication No. 52-38973). However, in the field of so-called anticorrosive agents in which active ingredients are directly added to aqueous systems, only those in combination with polymerized phosphates (see column CA Vol. 52.18153i) are known. In view of the above, the inventors of this invention
As a result of studying various zirconium compounds, we first confirmed that generally adding only a zirconium compound alone to an aqueous system does not provide an effective anticorrosive effect. Furthermore, tests were also conducted on the above-mentioned anticorrosion agent that combines a polymerized phosphate and a zirconium compound, but although some anticorrosion effect was obtained, excellent anticorrosion effect was not obtained at low concentrations, and it was not sufficient for practical use. I have confirmed that this is not the case. Various tests were also conducted on the use of anionic components such as phosphonic acids and oxycarboxylic acids, and cationic components such as amines in place of polymerized phosphates, but although some anticorrosive effects were still achieved,
It was not possible to obtain an excellent anticorrosion effect, and in addition, the storage stability as a preparation was insufficient, and there was a risk that zirconium would gradually form an insoluble salt and precipitate. The inventors of this invention aimed to create an anticorrosive agent that uses zirconium as a component and exhibits an excellent anticorrosive effect and has good storage stability.As a result of further research and consideration, the inventors of this invention discovered that aliphatic oxycarboxylic acid was added to the zirconium compound. The inventors have discovered that a three-component anticorrosive agent consisting of a combination of an organic phosphonic acid derivative and an organic phosphonic acid derivative exhibits the desired effect, and has thus arrived at this invention. Although there has been a proposal in the past for an anticorrosive agent that combines an active ingredient other than zirconium, that is, an aliphatic oxycarboxylic acid and an organic phosphonic acid derivative in this invention (Japanese Unexamined Patent Publication No. 71335/1983), the inventors have confirmed this. However, it still does not exhibit the excellent anticorrosive effect as the anticorrosive agent of the present invention, and there is no suggestion of adding zirconium. Thus, according to the present invention, there is provided a metal corrosion inhibitor which contains as active ingredients zirconium contained in the form of a compound or an ion, an aliphatic oxycarboxylic acid or a salt thereof, and an organic phosphonic acid derivative. provided. Zirconium used in this invention is contained in the form of a compound or in the form of an ion. The above-mentioned ion form refers to normal free ions such as zirconium ions and zirconyl ions, and also includes complex ions with aliphatic oxycarboxylic acids. In this invention, as such a zirconium-containing compound, it is usually appropriate to use a halide of zirconium or zirconyl, or an inorganic acid or an organic acid salt, and of course, a salt with other two components described below may also be used. .
Specific examples of these compounds include zirconium chloride, zirconyl chloride, zirconium iodide, zirconyl iodide, zirconium sulfate, zirconyl sulfate, zirconium nitrate, zirconyl nitrate, zirconium carbonate, zirconyl carbonate, ammonium zirconium carbonate, zirconyl ammonium carbonate,
Examples include zirconium acetate, zirconyl acetate, zirconyl sulfamate, and the like. Generally, these compounds are often added to an aqueous medium for use, so it is convenient to use compounds with high water solubility, and considering their marketability, price, etc., zirconyl chloride, zirconium sulfate, zirconyl nitrate, etc. It is preferable to use halides and inorganic acid salts. On the other hand, examples of aliphatic oxycarboxylic acids or salts thereof used in the present invention include gluconic acid, glycolic acid, citric acid, malic acid, tartaric acid, lactic acid, hydroxyacrylic acid, oxybutyric acid, and alkali metal salts or ammonium salts thereof. Generally, it is preferable to use gluconic acid, citric acid, malic acid, or a sodium salt thereof from the viewpoint of anticorrosion effect. Further, the organic phosphonic acid derivative used in this invention may be any water-soluble organic compound having at least one phosphonic group, and specifically,
Ethylphosphonic acid, isopropylphosphonic acid, butylphosphonic acid, methylene diphosphonic acid, 1,1
-Hydroxyethane diphosphonic acid, 1,1-aminoethane diphosphonic acid, 1,1-hydroxypropane diphosphonic acid, 1,1-hydroxybutane diphosphonic acid, 1,1-aminopropane diphosphonic acid, 1,1 -Aminobutane diphosphonic acid, nitrilotrismethylphosphonic acid, aminotrisethylidenephosphonic acid, ethylenediaminetetrakismethylphosphonic acid, hexamethylenediaminetetrakismethylphosphonic acid, diethylenetriamine-
Examples include pentakis-methylphosphonic acid, 2-phosphonoacetic acid, 2-phosphonopropionic acid, 2-phosphonosuccinic acid, and 2-phosphonobutane-1,2,4-tricarboxylic acid. Of these,
Preference is given to using 1,1-hydroxyethanediphosphonic acid, nitrilotrismethylphosphonic acid, 2-phosphonopropionic acid or 2-phosphonobutane-1,2,4-tricarboxylic acid. However, such organic phosphonic acid derivatives may be used in the form of alkali metal salts such as sodium or potassium salts or ammonium salts. The content ratio of the above-mentioned three components of this invention is: (a) 2 to 200 parts by weight of aliphatic oxycarboxylic acid or its salt, and (b) 0.01 to 50 parts by weight of organic phosphonic acid derivative, per 1 part by weight of zirconium. It is appropriate to
In particular, it is preferable to use (a) 2 to 60 parts by weight and (b) 1.0 to 20 parts by weight per 1 part by weight of zirconium from the viewpoint of anticorrosive effect. The composition of the present invention consisting of these three components can be used as a powder, slurry or paste preparation, glass-like solid preparation or aqueous solution, optionally containing a filler etc., but it can be used for convenience and dispersibility when added. From the viewpoint of solubility, etc., it is suitable to use it as an aqueous solution. When preparing an aqueous solution, usually
First, the zirconium compound is dissolved in water, and then the aliphatic oxycarboxylic acid and the organic phosphonic acid derivative are dissolved in this order, or the aliphatic oxycarboxylic acid is dissolved in water, and then the zirconium compound and the organic phosphonic acid derivative are heated in this order. It is preferable to mix and dissolve the ingredients. Changing the above order may cause precipitation in the preparation, which is not preferable. The total concentration of the active ingredients when preparing an aqueous solution depends on the solubility of each component, but is usually 5 to 55% by weight, preferably 20 to 45% by weight. The anticorrosive agent of the present invention has a total amount of active ingredients of 0.1 to 0.1 in the system to be treated for anticorrosion, that is, in water.
The purpose is achieved by adding 10,000 ppm, preferably 5 to 5,000 ppm. In general cooling water systems and boiler systems, an excellent corrosion prevention effect is usually obtained by adding 5 to 200 ppm equivalent, and in cooling water systems such as radiators. An excellent corrosion prevention effect can be obtained by adding 500 to 5000 ppm. Therefore, from another perspective, the present invention also provides a corrosion prevention method comprising adding a zirconium compound, an aliphatic oxycarboxylic acid or a salt thereof, and an organic phosphonic acid derivative to a system to be treated. The above-mentioned anticorrosive agent of the present invention is surprisingly effective against the surfaces of not only iron-based metals but also copper-based metals, aluminum, etc. due to the combined effect of zirconium ions, aliphatic oxycarboxylic acid anions, and organic phosphonic acid derivative anions. It forms a strong anticorrosion film even under relatively mild temperature conditions and exhibits excellent anticorrosion effects. The heavy metal contained is also convenient because it is low toxicity zirconium.
In addition, it has a remarkable anticorrosive effect compared to the effect of each active ingredient alone or the combination thereof, and is useful in reducing the amount of added chemicals in industry. Moreover, it is advantageous in that it does not particularly require a large number of anticorrosive agents even in systems where various metals are present. In addition, when using the anticorrosive agent of the present invention, other known anticorrosive agents may be used in combination, for example, hydrazine may be added to perform oxygen-scavenging corrosion protection. Hereinafter, the anticorrosive agent of the present invention will be described in detail with reference to Examples, but the present invention is not limited thereby. Example 1 (Formulation Example 1) Zirconium sulfate (Zr(SO ₄ ) ₂・4H ₂ O
2 parts by weight gluconic acid 30 parts by weight 1,1-hydroxyethanediphosphonic acid
10 parts by weight Water 58 parts by weight After dissolving zirconium sulfate in water at the above mixing ratio, gluconic acid and then 1,1-hydroxyethane diphosphonic acid were mixed and dissolved to obtain a solvent. (Formulation Example 2) Zirconyl nitrate ZrO (NO ₃ ) ₂・2H ₂ O (zirconium oxynitrate) 10 parts by weight Gluconic acid 15 〃 2-phosphonobutane-1,2,4-tricarboxylic acid 10 〃 Water 65 〃 At the above blending ratio After dissolving zirconyl nitrate in water, gluconic acid and then 2-phosphonobutane-1,
A solvent was obtained by mixing and dissolving 2,4-tricarboxylic acid. (Formulation example 3) Zirconyl chloride ZrOCl _{2.8H 2} o (zirconium oxychloride) 4 parts by weight Sodium citrate 30 2-phosphonopropionic acid 5 Water 61 After dissolving zirconyl chloride in water at the above mixing ratio A solution was obtained by mixing and dissolving sodium citrate and then 2-phosphonopropionic acid. (Formulation Example 4) Zirconium sulfate Zr (SO ₄ ) ₂・4H ₂ o 20 parts by weight Gluconic acid 15 〃 2-phosphonobutane-1,2,4-tricarboxylic acid 10 〃 Water 55 〃 Zirconium sulfate was dissolved at the above mixing ratio After gluconic acid was mixed and dissolved, the liquid temperature was heated to 50 to 60°C, and 2-phosphonobutane-1,2,4-tricarboxylic acid was mixed and dissolved to obtain a liquid preparation. (Formulation example 5) Zirconyl nitrate ZrO (NO ₃ ) ₂・ZH ₂ O 2 parts by weight Sodium malate 15 〃 Nitrilotrismethylphosphonic acid 3 〃 Sodium hydroxide 3 〃 Water 77 〃 Zirconyl nitrate was dissolved in water at the above mixing ratio A liquid preparation was obtained by sequentially mixing and dissolving sodium malate, nitrilotrimethylphosphonic acid, and sodium hydroxide. (Formulation example 6) Zirconium sulfate Zr (SO ₄ )・4H ₂ O 10 parts by weight Sodium citrate 40 〃 Nitrilotrismethylphosphonic acid-4-sodium salt 20 〃 Anhydrous sodium sulfate 30 〃 Mix uniformly at the above mixing ratio and dry. A powder was obtained. Each of the thus obtained formulations contains zirconium 1
When converted to parts by weight, the aliphatic oxycarboxylic acid or its salt contains 2.9 to 58.5 parts by weight, and the organic phosphonic acid derivative contains 2.0 to 19.5 parts by weight. Example 2 A standing test by immersion was conducted using a test piece. That is, an aqueous solution containing a predetermined amount of drug
cc in a beaker and immerse a test piece of copper, aluminum, or mild steel (commercial product name: SPCC). The shape of the test piece is 30 x 50 x 1 mm. This is left for 10 days while maintaining the liquid temperature at 30°C ± 3°C. After finishing, pull up the test piece and observe the condition of the test piece with the naked eye. The water used was Osaka city tap water with a liquid volume of 500c.c. The table shows the water quality and the results obtained. In this way, even if 50mg/each of zirconium sulfate, sodium gluconate, and 1,1-hydroxyethanediphosphonic acid were added alone, mild steel,
There was no significant difference in the anticorrosion effect against copper and aluminum compared to when no additive was added. Also, although a two-component system of zirconium sulfate and sodium gluconate or zirconium sulfate and 1,1-hydroxyethanediphosphonic acid exhibited some corrosion prevention effect, no excellent corrosion prevention effect was obtained. However, for Formulation Examples 1 to 6 in Example 1, the active ingredients were 42 mg/, 35 mg/, and 39 mg/, respectively.
It can be seen that additive amounts of mg/, 45 mg/, 20 mg/, and 28 mg/ exhibit excellent anticorrosion effects on mild steel, copper, and aluminum.

【table】

【table】

[Table] Example 3 A corrosion prevention test in hot water was conducted using the test piece. A mild steel test piece having the same shape as that used in Example 2 and having a hole with a diameter of 4 mm in the upper part was attached to a stainless steel stirring rod and immersed in Test Solution 1 containing a predetermined amount of drug. The liquid is contained in a flat-bottomed beaker at the bottom of a seperate flask fitted into an annular mantle heater. The water temperature is maintained at 50℃ using a thermostat and mantle heater, while a stirring rod linked to a motor is used.
Test for 5 days under rotation of 100 rpm (100 revolutions per minute). The water used was Osaka city tap water. MDD in accordance with JIS KO100 after testing
(1dm ² Corrosion mg loss per day, i.e. mg/dm ²
day). The results obtained are shown in the table. In this way, as in Example 2, each component may be used alone or in combination.
It can be seen that the three-component anticorrosive agent of the present invention exhibits an excellent anticorrosion effect even though the additive concentration is lower than that of the anticorrosive agent based on the three-component anticorrosive agent. Furthermore, it can be seen that an excellent anti-corrosion effect can be achieved with a lower additive concentration than the conventionally known two-component system of a zirconium compound and a polymerized phosphate.

【table】

[Table] Shows the concentration of ingredients.
Example 4 The effect of chemicals in a soft water boiler was investigated using an autoclave. That is, a predetermined amount of the drug was added to 800 ml of 5 times concentrated water of Osaka City Water Soft Water, and the mixture was charged into an autoclave. A mild steel test piece similar to that in Example 3 is suspended from a stirring rod, linked to a motor, immersed in the liquid, and rotated at 100 rpm. After sealing the autoclave, the autoclave is tested for 3 days under stirring and pressurized conditions of 15 kg/cm ² at approximately 200°C. This soft water contained 10 to 11 ppm of dissolved oxygen, so hydrazine was used as an oxygen scavenger in all cases tested.
Added 12ppm. After the test was completed, MDD was determined in the same manner as in Example 3. The quality of the soft water used is shown in the table, and the results obtained are shown in the table.

【table】

【table】

【table】

[Table] *The numbers in brackets in the concentration column indicate the concentration of the active ingredient.
In this way, even in soft water boiler water, the three-component anticorrosive agent of the present invention has 168 mg/, 156 mg/, 138 mg/, and 200 mg/ of active ingredients, compared to the case where each component is added alone or the two-component system is added at 200 mg/.
It can be seen that an excellent anticorrosive effect can be achieved with a smaller addition amount.

Claims (1)

[Scope of Claims] 1. A metal anticorrosive agent characterized by containing as active ingredients zirconium contained in the form of a compound or ion, an aliphatic oxycarboxylic acid or a salt thereof, and an organic phosphonic acid derivative. 2. The anticorrosive agent according to claim 1, which contains 2 to 200 parts by weight of an aliphatic oxycarboxylic acid or a salt thereof and 0.01 to 50 parts by weight of an organic phosphonic acid derivative per 1 part by weight of zirconium. 3. The anticorrosive agent according to claim 1, which contains 2 to 60 parts by weight of an aliphatic oxycarboxylic acid or a salt thereof and 1.0 to 20 parts by weight of an organic phosphonic acid derivative per 1 part by weight of zirconium. 4. The anticorrosive agent according to any one of claims 1 to 3, wherein zirconium is contained in the form of a halide or inorganic acid salt of zirconium or zirconyl. 5. The anticorrosive agent according to claim 4, wherein zirconium is contained in the form of zirconyl chloride, zirconium sulfate, or zirconyl nitrate. 6. The anticorrosive agent according to any one of claims 1 to 3, wherein zirconium is contained in the form of a complex or salt of an aliphatic oxycarboxylic acid or an organic phosphonic acid derivative. 7 Claims 1 to 7, wherein the aliphatic oxycarboxylic acid is gluconic acid, citric acid, or malic acid.
The anticorrosive agent according to any one of Items 3 and 5. 8 Claim 1 in which the organic phosphonic acid derivative is 1,1-hydroxyethane diphosphonic acid, nitrilotrismethylphosphonic acid, 2-phosphonobutane-1,2,4-tricarboxylic acid, or 2-phosphonopropionic acid The anticorrosive agent according to any one of items 3 and 5. 9. The anticorrosive agent according to any one of claims 1 to 8, which is used in a cooling water system or a boiler water system.