JPS5993886A - Anticorrosive for metal - Google Patents

Abstract

PURPOSE:To obtain an anticorrosive for metal having a significant anticorrosive effect and superior storage stability by combining a Zr or Sn compound with an aliphatic oxycarboxylic acid or a salt thereof and a polymer of an aliphatic lower unsatd. carboxylic acid or a salt thereof. CONSTITUTION:An anticorrosive for inhibiting the corrosion of steel, mild steel, Cu-base metal and Al-base metal in an aqueous medium is prepared by dissolving a Zr or Sn compound with low toxicity such as zirconium chloride, zirconium sulfate or stannous chloride, an aliphatic oxycarboxylic acid such as gluconic acid or citric acid or the Na or K salt thereof by 5-60 parts by weight per 1 part Zr or Sn, and a polymer of an aliphatic lower unsatd. carboxylic acid with 1,000-2,000mol.wt. such as polyacrylic acid or polymaleic acid or the Na or K salt thereof by 1-10 parts in a proper amount of water. The anticorrosive forms a highly anticorrosive film on the surface of Fe-, Cu- or Al-base metal and produces a significant anticorrosive effect.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a metal corrosion inhibitor. 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. The present invention relates to a metal corrosion inhibitor which is suitable and also has low toxicity and does not contain phosphorus.

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, iron manufacturing, paper manufacturing, textile factories, etc.
It is desired to prevent corrosion of various metals used in cooling systems such as diesel engines and radiators of automobiles, and various anticorrosive agents have been proposed.

Such anticorrosive agents include those mainly containing heavy metal ions such as chromium and zinc, phosphoric acid, polymerized phosphoric acid, phosphonic acid,
A variety of materials have been proposed, including those based on anionic components such as molybdic acid, tungstic acid, aliphatic oxycarboxylic acids, and polyphenols, those based on cationic components such as amine compounds, and combinations of these.

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. The use of phosphorus compounds is also a problem from the viewpoint of eutrophication. In this regard, the inventors of the present invention first focused on the use of zirconium and tin, which have particularly low toxicity among heavy metals, as active ingredients in anticorrosive agents.

Zirconium is originally known as a heavy metal with low toxicity (J, 5chubert, 5science 1
05.389-390 (1947) and J. Nutr.
95.95-101 (1968) etc. Such zirconium is an active ingredient in so-called rust inhibitors, which prevent corrosion by coating metal surfaces with a preparation having an appropriate viscosity. It is known that it can be applied as part of the
(See Publication No. 38973).

However, in the field of so-called anti-corrosion agents, in which active ingredients are added directly to water systems, only those in combination with polymerized phosphates (0, A, see column 1.52.181531) are known. .

Furthermore, tin is also known to have low toxicity. In other words, the Ministry of Health and Welfare Ordinance No. 11 of May 6, 1966
No. 1 (Act No. 117 of 1955), "Ministerial Ordinance on Water Quality Standards," does not regulate tin, and tin is not listed as a subject of wastewater standards. In addition, tin is painted on the inner surfaces of edible canned goods, and tin tableware is also used, making it extremely safe.

In view of the above, the inventors of this invention investigated various zirconium and tin compounds and found that, in general, adding zirconium and tin compounds alone to an aqueous system does not provide an almost effective anti-corrosion effect. I confirmed that it is not possible. We also conducted tests on the anticorrosive agent that combines a polymerized phosphate and a zirconium compound, as described above, and although some anticorrosive effects were obtained, excellent anticorrosive effects were not obtained at low concentrations, and the results were insufficient for practical use. We have confirmed that this is not the case. In place of polymerized phosphates, anionic components such as phosphonic acids and oxycarboxylic acids, and cationic components such as amines are used in combination (various tests have been carried out, but although some anti-corrosion effects have been achieved, they are still excellent. In addition, the storage stability of the formulation was insufficient, and there was a risk that zirconium or tin would gradually form an insoluble salt and precipitate.

The inventors of this invention aimed to develop an anticorrosive agent containing zirconium or tin as a component that exhibits an excellent anticorrosive effect and has good storage stability.As a result of further research and consideration, the inventors of the present invention discovered a zirconium or tin compound. The inventors have discovered that a three-component anticorrosive agent consisting of a combination of an aliphatic oxycarboxylic acid and an aliphatic lower unsaturated carboxylic acid polymer or a salt thereof exhibits the desired effect, and has thus arrived at the present invention.

According to the present invention, zirconium or tin contained in the form of a compound or ion, an aliphatic oxycarboxylic acid or a salt thereof, and an aliphatic lower unsaturated carboxylic acid polymer or a salt thereof are contained as active ingredients. A metal corrosion inhibitor is provided.

Zirconium or tin used in this invention is contained in the form of a compound or in the form of an ion.

The above ion form refers to normal free ions such as zirconium ions, zirconyl ions, and tin 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 the other two components of the invention described below may also be used. It's okay. Specific examples of these compounds include zirconium chloride, zirconyl chloride, zirconium iodide, zirconyl iodide, zirconium sulfate,
Examples include zirconyl sulfate, rufnium nitrate, zirconyl nitrate, zirconium carbonate, zirconyl carbonate, ammonium zirconium carbonate, ammonium zirconyl carbonate, zirconium acetate, zirconyl acetate, and zirconyl sulfamate.

Further, examples of the tin compound used in this invention include stannous chloride, stannous chloride, stannous sulfate, 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. Preference is given to using zirconyl or stannous chloride.

The aliphatic oxycarboxylic acids or salts thereof used in this invention include gluconic acid, glycolic acid, citric acid, malic acid, tartaric acid, lactic acid, hydroxyacrylic acid, oxybutyric acid, and their alkali metal salts or ammonium salts. 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 aliphatic lower unsaturated carboxylic acid polymer or its salt used in the present invention is represented by the following formula (I): (wherein, R~R3
each independently represents a hydrogen atom, a methyl group, or a carboxyl group, and n represents an integer of O or 1) A homopolymer or a copolymer of two or more of these monomers, or any of the above monomers A water-soluble polymer consisting of a copolymer containing 40 mol% or more of the above monomer component, which is a copolymer with another compound having an ethylenic double bond that can be copolymerized with the polymer (however, the molecular weight of each of these homopolymers and copolymers is 500% or more)
~100,000) or their salts. Depending on the case, it may be a mixed polymer of each of these homopolymers and copolymers.

Specific examples of the compound represented by formula (I) include acrylic acid, methacrylic acid, maleic acid, itaconic acid, crotonic acid, methylmaleic acid, fumaric acid, and the like. Other compounds having an ethylenic double bond that can be copolymerized with any of the monomers of formula (I) include acrylamide,
Methacrylamide, methylol acrylamide, acrylonitrile, methyl acrylate, ethyl acrylate, isopropyl acrylate, methyl methacrylate, methacrylic acid includes polyacrylic acid, polymethacrylic acid, polymaleic acid, polyitaconic acid, polymethylmaleic acid,
Polyfumaric acid, acrylic acid methacrylic acid copolymer, acrylic acid maleic acid copolymer, acrylic acid itaconic acid copolymer, acrylic acid fumaric acid copolymer, acrylic acid methylmaleic acid copolymer, methacrylic acid itaconic acid copolymer, acrylic acid acrylamide copolymer,
Acrylic acid methacrylamide copolymer, acrylic acid methylol acrylamide copolymer, acrylic acid acrylonitrile copolymer, acrylic acid methyl acrylate copolymer, acrylic acid ethyl acrylate copolymer, acrylic acid isopropyl acrylate copolymer, acrylic acid styrene copolymer, acrylic acid acrolein copolymer , acrylic acid methyl methacrylate copolymer,
Ethyl methacrylate copolymer, acrylonitrile methacrylate copolymer, acrylamide methacrylate copolymer, methacrylamide methacrylate copolymer, methylolacrylamide methacrylate copolymer, acrylonitrile methacrylate copolymer, methyl methacrylate acrylate copolymer, methacrylate ethyl acrylate copolymer, methacrylic acid Examples include acrolein copolymer. More preferred among these are polyacrylic acid, polymethacrylic acid, polymaleic acid, acrylic acid methacrylic acid copolymer, acrylic acid maleic acid copolymer, acrylic acid itaconic acid copolymer,
They are acrylic acid acrylamide copolymer and methacrylic acid methylol acrylamide copolymer. The molecular weight of these polymers is 500 from the viewpoint of corrosion resistance and solubility.
~100,000 is suitable, more preferably 1
000 to 20000.

These polymers may be used in their sodium, potassium, or ammonium salts if necessary.

In addition, when using a copolymer, at least formula CI)
The monomer component represented by is 40 mol% or more in the polymer.
It is necessary to contain two. If the monomer component represented by formula (I) is less than 40 mol %, the anticorrosion effect will be insufficient, which is inappropriate. Note that these polymers and copolymers can be produced by known methods such as radical polymerization.

The content ratio of the above three components of the present invention is as follows: (a) 1 to 200 parts by weight of aliphatic oxycarboxylic acid or its salt, and (b) aliphatic lower unsaturated carboxylic acid to 1 part by weight of zirconium or tin. It is appropriate to use 0.1 to 30 parts by weight of the acid polymer or its salt, especially (a) 5 to 60 parts by weight, and (b) 1.0 to 1 part by weight for 1 part by weight of zirconium or tin.
It is preferable to use 0 parts by weight from the viewpoint of anti-corrosion 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 aliphatic oxycarboxylic acid or its salt is dissolved in water, and then the zirconium or tin compound and then the polymer or its salt are mixed and dissolved in this order while heating. So clever. Changing the above order may cause precipitation in the preparation, which is not preferable. The total concentration of the active ingredients in an aqueous solution depends on the solubility of each component, but is usually 5 to 55% by weight, preferably 20 to 45% by weight.

Such an anticorrosive agent of the present invention has a total amount of active ingredients of 0.1 to 10,000 p in the system to be treated for anticorrosion, that is, in water.
pm, preferably added in an amount of 5 to 5,000 ppm to achieve the purpose; - In membrane cooling water systems and boiler systems, an excellent corrosion prevention effect is usually obtained by adding in an amount of 5 to 200 ppm; In a cooling water system, an excellent anticorrosion effect can be obtained by adding 500 to 5000 ppm.

Therefore, from another point of view, the present invention provides anti-corrosion treatment comprising adding a zirconium or tin compound, an aliphatic oxycarboxylic acid or a salt thereof, and an aliphatic lower unsaturated carboxylic acid polymer or a salt thereof to a system to be subjected to anti-corrosion treatment. A method is also provided.

The above-mentioned anticorrosive agent of the present invention has a relatively strong effect on the surfaces of not only iron-based metals but also copper-based metals, aluminum, etc. due to the combined effect of zirconium ions or tin ions, aliphatic oxycarboxylic acid anions, and polymers. It forms a strong anti-corrosion film even under mild temperature conditions and exhibits excellent anti-corrosion effects. The heavy metals contained are also low-toxic zirconium or tin, which is advantageous.
In addition, it has a remarkable anticorrosion effect compared to the effect of each active ingredient alone or two of them, 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. The anticorrosive agent of the present invention using tin has been found to have an excellent anticorrosion effect in boiler water systems.

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 deoxidizing corrosion protection in combination).

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 2 parts by weight (Zr(
So 4〃2” 4H2 Sodium ligluconate 30〃Sodium polyacrylate 2〃(Molecular weight 80
00) Sodium hydroxide (pH adjuster) 1
water 65
〃After dissolving sodium gluconate in water with the above mixing ratio, zirconium sulfate, sodium polyacrylate,
Sodium hydroxide was mixed and dissolved in 11 ρ orders to obtain a uniform and stable solution. (The molecular weight is an approximate value based on the Ostwald method. The same applies hereinafter. (Formulation Example 2) Zirconyl chloride (Zr0O1.8HO) 5 parts by weight (Zirconium oxynitrate Sodium nogluconate 25 Sodium polymethacrylate 3 (Molecular weight 7000) ) Wednesday 67
〃Sodium gluconate is dissolved in water at the above blending ratio, and then sodium polymethacrylate is mixed and dissolved with zirconium sulfate to create a uniform and stable solution hq.

(Formulation Example 3) Zirconyl nitrate (ZrO(NO3), -2H20)
5 weight m (zirconium oxynitrate λ glunicon l!11230〃 Polymaleic acid (molecular weight 100 (N 10
/1 Wednesday 5
5 After dissolving gluconic acid in water at the above blending ratio,
Zirconyl nitrate and then polymaleic acid were mixed and dissolved to obtain a uniform and stable solution.

(Formulation Example 4 Zirconium Nosulfate (Zr (so,ノ,・4H20)5
Part by weight Citric acid 25 Acrylic acid methacrylic acid copolymer 5 (Molecular weight 4000. Reaction molar ratio 1:l) Water
65 After dissolving citric acid in water at the above blending ratio, zirconium sulfate and then acrylic acid methacrylic acid copolymer were mixed and dissolved to obtain a uniform and stable solution.

(Formulation Example 5) Zirconium sulfate (Zr (SO4), -4H20)
15 parts by weight gluconic acid
20 Polymaleic acid (molecular weight 1000) 1
0/7 Wednesday
55 After dissolving gluconic acid in water at the above mixing ratio, zirconium sulfate was mixed and dissolved, and the temperature of the solution was lowered to 60°C.
After heating to ~70°C, polymaleic acid was mixed and dissolved to obtain a uniform and stable solution.

(Formulation Example 6) Zirconyl nitrate (ZrO(NO3)2” 2H20
20 parts sodium malate
70〃Methylol methacrylate acrylic 10
p-amide copolymer (molecular weight 1000, reaction molar ratio 3:l) After uniformly mixing each component at the above mixing ratio, the mixture was dried to obtain a powder.

(Formulation Example 7) Zirconyl chloride (Zr0Oj?2 ・8 H2O)
5 M It part sodium tricconate
5Q tt Acrylic acid itaconic acid copolymer 20〃 (Molecular weight 6000, reaction molar ratio 2:1) Sodium sulfate (anhydrous salt) 25〃 (Seed stabilizer) After uniformly mixing each component at the above mixing ratio, drying to form a powder I got it.

(Formulation Example 8) (i7a rp2 zirconium (Zr(So, Chaos-41
120] 10 parts by weight sodium citrate
80 Acrylic acid acrylamide copolymer
10 (molecular weight 6000, reaction molar ratio 3:1) Each component was uniformly mixed at the above mixing ratio and then dried to obtain a powder.

Each of the thus obtained preparations contains 5 parts of aliphatic oxycarboxylic acid or its salt per 1 part by weight of zirconium.
．． 2 to 58.5 parts by weight, 1 part of polycarboxylic acid or its salt
, 5 to 14.2 parts by weight.

(Formulation Example 9) Stannous chloride (SnO12-2H20)
2 parts by weight sodium gluconate
30 Sodium polyacrylate
5 Water
63 After dissolving sodium gluconate in water at the above mixing ratio, stannous chloride and then sodium polyacrylate were mixed and dissolved to obtain a uniform and stable solution.

(Formulation Example 10) Stannic chloride (SnO/r, "3H20) '
to'tE-1it part sodium gluconate
15 Polymaleic acid (molecular weight 1000) 10 /7 Water
65 After dissolving sodium gluconate in water at the above blending ratio, stannic chloride and then polymaleic acid were mixed and dissolved to obtain a uniform and stable solution.

(Formulation Example 11) Stannous sulfate (5nSO4) 4 parts by weight Sodium citrate 30
〃Acrylic acid methacrylic acid copolymer 5 〃
(molecules 14000, reaction molar ratio 1:1) water
61 // After dissolving sodium citrate in water at the above blending ratio, stannous sulfate and then acrylic acid methacrylic acid copolymer were mixed in a 17N+ mixed bath to obtain a uniform and stable solution.

(Formulation Example 12) JjK stannous (S) 107?2.2N(20)2
0 Jugoto Sodium Gluconate 1
5 Acrylic acid acrylamide copolymer lO
(Molecular weight 6000, reaction molar ratio 3:1) water
55 After dissolving sulfur-IJium gluconate in water at the mixing ratio described in 〃-,
Mix and dissolve stannous chloride and then lower the temperature of the solution to 50-60'C.
After heating, the acrylic acid acrylamide copolymer was mixed and dissolved to obtain a uniform and stable solution.

(Formulation Example 13) Stannous chloride (SnON2 2H20)
2 ”JE Sodium Malate
15 tt Sodium polyacrylate
3 (molecular weight 8000) Sodium hydroxide 3 Water
77 〃
After dissolving sodium malate and sodium hydroxide in water at the above mixing ratio, stannous chloride and then sodium polyacrylate were mixed and dissolved to obtain a uniform and stable solution.

(Formulation Example 14) Tin chloride (Sn%' 2H20J
1 part by weight sodium gluconate
3Q // Sodium polyacrylate
5 (molecular weight 8000) Water 64
After dissolving sodium gluconate in water at the above mixing ratio, stannous chloride and then sodium polyacrylate were mixed and dissolved to obtain a uniform and stable solution.

Each of the thus obtained formulations contains 1.4 to 1.4 to 1.4 parts of aliphatic oxycarboxylic acid or its salt, calculated based on 1 part by weight of tin.
57 parts by weight, polycarboxylic acid or its salt is 1.0 to 9.
It contains 5 parts by weight.

Example 2 A static test by immersion was conducted using the test piece.

That is, 500 cc of an aqueous solution containing a predetermined amount of the drug was placed in a beaker and mixed with copper, aluminum, and soft @ (commercial product name 5POO).
immerse the test piece. The shape of the test piece is 30
The size is 50 x 1 mm. The liquid temperature is 30°C.
Leave it for 10 days while keeping it at ±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 500 cc. Table I shows the water quality, and Table 2 shows the results obtained.

Table ■ (Osaka City Minakami Water Water Quality) Table ■ (Results of static test) ◎: Very good, O: No discoloration or rust observed. △: Discoloration is visible. M: One to several pitches can be seen, × A lot of pitching can be seen, XX: Fully corroded.

In this way, zirconium sulfate, stannous chloride, sodium gluconate, sodium polyacrylate, and sodium polymethacrylate were each used at 50 my/I! Even when it was added, there was no significant difference in the anticorrosive effect on mild steel, copper, and aluminum compared to when it was not added. Furthermore, two-component systems of zirconium sulfate or stannous chloride and sodium gluconate, zirconium sulfate or stannous chloride, and sodium polyacrylate also exhibit some anticorrosion effect, but no excellent anticorrosion effect can be obtained. Ta. However, it can be seen that Formulation Examples 1 to 14 in Example 1 exhibit excellent anticorrosion effects against mild steel, copper, and aluminum when the active ingredient is added in an amount of 20 my/ff to 45 my/(J).

Example 3 A corrosion prevention test in hot water was conducted using a test piece. Diameter 4 on the top of the same shape as that used in Example 2
A mild steel test piece with a mm hole is attached to a stainless steel stirring rod and immersed in a test solution 11 containing a predetermined amount of drug. The liquid is contained in a flat-bottomed beaker below a separable flask fitted into an annular mantle heater. Adjust the water temperature to 5° using the thermostat and mantle heater.
110 with a stirring bar linked to a motor while maintaining the temperature at 0°C.
The test was carried out for 5 days under rotation at 0 rpm (100 revolutions per minute).The water used was Osaka Heavy Water Supply Water.

After the test, M, D, D (
l dm”corrosion my loss per day, mf/dm2
day) was calculated. The results obtained are shown in Table ■.

Table ■ (Effects on mild steel in hot water) Table V (Effects on boiler water Table V (Continued)* The numbers in parentheses in the temperature column indicate the concentration of the active ingredient.

In this way, even in soft water and high-temperature water, the three-component anticorrosive agent of the present invention has 136 my/11 active ingredients as compared to the case where each component alone or a two-component system is added at 200 my/l.
~156 my/l! It can be seen that an excellent anticorrosive effect can be achieved with an addition amount smaller than 200 my/().

Example 5 As described above, as in Example 2, the three-component anticorrosive agent of the present invention exhibits an excellent anticorrosion effect even though the addition temperature is lower than that of each component alone or the two-component anticorrosive agent. I understand. 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 condensed phosphate.

Example 4 The effect of chemicals in a soft water boiler was investigated using an autoclave. That is, Osaka Heavy Water Supply Water Softened Water 5 times concentrated water 8
00 ml of the specified drug was added, and the mixture was placed in an autoclave. A mild steel test piece similar to that in Example 3 was suspended on a stirring rod, moved by a motor, and immersed in the liquid for 10 minutes.
Rotate at 0 rpm. After sealing the autoclave,
The test is carried out for 3 days under pressure and heating conditions of 15 Kgf/cm and approximately 200°C under stirring. This soft water contained 10 to 11 ppm of dissolved oxygen, so hydrazine hydrate (N2H4.
H2O) as hydrazine (N2H4) 12 ppm
Added.

After the test was completed, M, D, and D were determined in the same manner as in Example 3.

The quality of the soft water used is shown in Table 2, and the results obtained are shown in Table 2.

Table ■ (Water quality of soft water) Table ■ (Effects in boiler water) Table ■ (continued) The numbers in parentheses in the concentration column indicate the concentration of the active ingredient.

In this way, even in soft water and high-temperature water, the three-component anticorrosive agent of the present invention has an active ingredient content of 136 mg/l to 1, compared to the case where each component is added alone or the two-component system is added at 200 my/l.
It can be seen that excellent anticorrosive effects can be achieved with addition amounts smaller than 56 my/(l and 200 mg/(4).

Example 5 The dispersion effect of chemicals on iron in a soft water boiler was tested using an autoclave (high pressure cooker).

A predetermined amount of chemicals was added to test water 11, and the mixture was placed in an autoclave. After sealing the autoclave, use a stirrer to
The test is carried out for 3 days under pressure and heating conditions of about 200°C at 15 Ky/cm under stirring at rpm. After the test, the supernatant liquid of the test water was cooled to room temperature for 1 hour.
mj? were collected and the total iron concentration was measured.

The quality of the soft water used is shown in Table M, and the results obtained are shown in Table 3. The test water used was synthetic soft water modeled after the quality of water that causes scaling problems in actual soft water boilers.

Table ■ (Soft water quality) Note that the dispersion rate was calculated using the following formula.

As described above, it has been found that the three-component anticorrosive agent of the present invention has a sufficient iron dispersion effect. For example, in a boiler can or heat exchanger system, iron brought into the can or heat exchanger system by water supply can be sufficiently removed from the system by blowing, so that iron that is brought into the can or heat exchanger system by water supply can be sufficiently removed from the system. It does not form scale in the heat exchanger system and prevents energy loss due to inhibition of heat transfer, and can prevent accidents due to pipe blockage or bursting.

Claims (1)

[Claims] 1. Zirconium or tin (contained in the form of a compound or an ion), an aliphatic oxycarboxylic acid or a salt thereof, and an aliphatic lower unsaturated carboxylic acid polymer or its 2. 1 to 200 parts by weight of aliphatic oxycarboxylic acid or a salt thereof, and 1 to 200 parts by weight of aliphatic lower unsaturated carboxylic acid per 1 part by weight of zirconium or tin; Acid polymer or its salt is 0.1-3
The anticorrosive agent according to claim 1, which contains 0 parts by weight. 3. For 1 part by weight of zirconium or tin, 5 to 60 parts by weight of aliphatic oxycarboxylic acid or its salt, and 1.0 to 10 parts of aliphatic lower unsaturated carboxylic acid polymer or salt thereof.
The anticorrosive agent according to claim 1, which contains part by weight. 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 tin is contained in the form of stannous chloride, stannic chloride, or stannous sulfate. 7. Aliphatic oxycarboxylic acids include gluconic acid, citric acid,
Claims $ that are malic acid or its sodium salt
The anticorrosive agent according to any one of items 1 to 3. 8. The aliphatic lower unsaturated carboxylic acid polymer has the following formula (■):
R3(CH2)nOOOH (wherein, R~R3 each independently represent a hydrogen atom, a methyl group, or a carboxyl group, and n represents an integer of 0 or 1. A homopolymer whose monomer is a compound represented by n. Or a water-soluble polymer consisting of a copolymer of two or more of these types, or a copolymer containing 40 mol% or more of the above heptamer component in a 9 copolymer with another compound having an ethylenic double bond copolymerized with any of the above monomers. (However, the molecular weight of each of these homopolymers and copolymers is 500
~100000) Claim range Nl 1
The anticorrosive agent according to any one of items 1 to 3. 9. The aliphatic lower unsaturated carboxylic acid polymer has a molecular weight of 100
0 to 20000 polyacrylic acid, polymethacrylic acid,
The anticorrosive agent according to any one of claims 1 to 3, which is a polymaleic acid, an acrylic acid maleic acid copolymer, an acrylic acid methacrylic acid copolyacid methylol acrylamide copolymer. The anticorrosive agent according to any one of claims 1 to 9, which is used for a 1O0 cooling water system or a boiler water system.