JP2003082479A - Anticorrosive, and corrosion prevention method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an anticorrosive which can reduce the amounts of a phosphorus based compound and a zinc based compound in a water system, and can reduce an environmental load, and to provide a corrosion prevention method. SOLUTION: A zinc compound, a phosphorus compound, and a water soluble copolymer at least consisting of the monomer unit of metha crylic acid and/the salt thereof, the monomer unit of metha crylamide - alkaly-and/or arylsulfonic acid and/or the salt thereof and the monomer unit of substituted metha crylamide are blended to prepare the anticorrosive. This anticorrosive can advantageously be applied, in particular, to a cooled water system in a large factory.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a metal anticorrosive agent and an anticorrosion method in an aqueous system, and more particularly to an anticorrosive agent and an anticorrosion method capable of effectively preventing corrosion of a metal member in an aqueous system. INDUSTRIAL APPLICABILITY The present invention can be applied to various water treatment systems such as a cooling water treatment system, a wastewater treatment system, an industrial water treatment system, and a pure water treatment system.

[0002]

2. Description of the Related Art Cooling water is widely used for cooling equipment in the steel industry and various chemical plants. In such a cooling water system, the pipe is often made of mild steel, and the heat exchanger is often made of a copper-based metal such as copper or a copper alloy. How to prevent such corrosion of metal pipes and heat exchangers is one of the major problems of the cooling water system. Generally, hardness components such as calcium are present in the cooling water used in the cooling water system, and part of the water evaporates for cooling, so some of the cooling water is forcibly replaced. The hardness component is concentrated unless otherwise specified. Since water containing a large amount of hardness component generally does not easily corrode metals, it is possible to prevent corrosion by appropriately concentrating cooling water and increasing the concentration of hardness component.
In such a system, it is also possible to prevent the failure of the cooling water system by adding only the water-soluble polymer-based dispersant in order to prevent the blockage of the piping and the scale that hinders the heat transfer of the heat exchanger. .

On the other hand, in recent years, when environmental problems have been highlighted, there has been an active movement to reduce the amount of waste water containing harmful substances and the like from various facilities and factories. In large factories such as complex factories, the makeup water is often industrial water in the area, and from the viewpoint of cost, it is often the case that phosphorus / zinc-based precipitation film type anticorrosion methods are used, but the scale of cooling water must be scaled. Low concentration (1 to 4 times concentration)
There are many cases of operating by driving. Therefore, the concentration of water quality components such as chloride ions, sulfate ions, silica, and organic substances in the cooling water is low, and in such a cooling water system, the hardness component is generally about 10 to 200 mg / liter (as CaCO ₃ ), Highly corrosive to various types, especially mild steel. As an anticorrosion agent used in such a water-based water system, the anticorrosion effect is weak only with a water-soluble polymer dispersant,
Due to the cost advantage, it is often the case that a water-soluble polymer dispersant and a phosphorus / zinc anticorrosive agent are used in combination. However, in large factories, the amount of cooling water used is large, and in proportion to this, the amount of cooling water treatment chemicals such as the phosphorus / zinc anticorrosive agent also increases. Therefore, it is a permanent problem to reduce the amount of phosphorus / zinc anticorrosive agent, which has a particularly large environmental load, as much as possible. In addition, the water treatment agent containing a zinc-based compound as a main component as an anticorrosive agent is applicable to a water quality range (particularly p
However, it is difficult to secure a stable anticorrosion effect for a long time due to the precipitation of zinc hydroxide, and a large amount of zinc is harmful to the environment. Also,
Since the cooling water system circulates the water while partially evaporating the water, the operation of discharging a part of the cooling water by blowing is repeated to prevent the deterioration of the water quality beyond a certain level due to the progress of evaporation. Emitting and releasing chemical compounds into the sea, rivers and lakes may cause eutrophication

[0004]

Zinc salts as zinc compounds are produced by the PRTR method (“Pollutant Release and Tran
sfer registration ”is a designated chemical substance under the Waste Control Law), and as described above, if phosphorus compounds such as phosphates are discharged into the sea, rivers or lakes and released, they will cause eutrophication. Therefore, it is necessary to reduce the usage amount as much as possible. However, the lack of phosphorus and zinc components is directly linked to corrosion damage, so normally a safe amount is added to the cooling water treatment chemicals. However, many conventional cooling water treatment agents do not have sufficient dispersibility of the water-soluble polymer with respect to the phosphorus / zinc components such as phosphates and zinc salts, so the phosphorus / zinc-based insolubilization is locally caused in places with high heat load. This is a problem because it often deposits things more than necessary and causes scale failure. Therefore, due to the scaling of phosphorus / zinc components, the phosphorus / zinc components in water are insufficient and the corrosion progresses secondarily, even though the phosphorus / zinc components are blended in sufficient amounts as anticorrosive agents. There were cases. The present invention seeks to overcome the drawbacks of the prior art.

[0005]

Therefore, the present inventors have
By adding a certain amount of a specific water-soluble copolymer to a water treatment agent such as a cooling water treatment agent, phosphorus / zinc anticorrosive components such as phosphates and zinc salts can be efficiently dispersed by the water-soluble copolymer. In addition to improving the anticorrosion efficiency with phosphorus and zinc, by utilizing the anticorrosion effect of the water-soluble copolymer itself, it is possible to have a synergistic effect on the anticorrosion ability, and thus it can be used as a water treatment agent. The inventors have found that the amount of phosphorus and zinc components used can be markedly reduced while maintaining the dispersion effect, thereby reducing the environmental load, and have completed the anticorrosive agent and anticorrosion method of the present invention.

That is, the present invention relates to a zinc compound and a phosphorus compound,
And at least a monomer unit of (meth) acrylic acid and / or a salt thereof, (meth) acrylamide-alkyl-
And / or a water-soluble copolymer comprising a monomer unit of an aryl-sulfonic acid and / or a salt thereof and a monomer unit of a substituted (meth) acrylamide. is there.

The anticorrosive agent and the anticorrosion method for an aqueous system of the present invention effectively prevent the corrosion of mild steel pipe steel etc. due to the synergistic effect of a phosphorus compound, a zinc compound and the above water-soluble copolymer, and a cooling water system. In equipment such as, generally, phosphate, which is easy to adhere as a scale to the high temperature part, is well dispersed, so it does not adhere and does not cause heat transfer inhibition in the high temperature part. can do.

Specific examples of the zinc compound in the anticorrosive agent of the present invention include zinc sulfate, zinc chloride, zinc acetate, sodium zincate, potassium zincate and the like. The anti-corrosion effect of the zinc compound on the precipitate film is effective even if the zinc compound alone is added in a sufficient amount.
However, in order to prevent zinc from scaling and taking into consideration its harmful effects, we want to minimize the amount used.
The present invention, as a result of intensive studies to reduce the amount of zinc compound used, by simultaneously adding the water-soluble copolymer having the effect of dispersing the zinc compound, while reducing the amount of zinc compound used, We have succeeded in providing a further anticorrosion effect compared to the past.

As the phosphorus compound, specifically, for example,
Inorganic phosphorus compounds such as orthophosphoric acid, pyrophosphoric acid, tripolyphosphoric acid, hexametaphosphoric acid and their salts, nitrilotrimethylenephosphonic acid, 1-hydroxyethylidene-
1,1-diphosphonic acid, 2-phosphonobutane-1,2,
Examples thereof include organic phosphorus compounds such as 4-tricarboxylic acid and salts thereof. In order to enhance the anticorrosion effect, it is preferable to use a combination of the above-mentioned inorganic phosphorus compound and the above-mentioned organic phosphorus compound. In this case, the weight ratio of inorganic phosphorus compound / organic phosphorus compound is 1:10 to 10 :. It is preferably 1. In the present invention, as a result of improving the dispersion efficiency of the phosphorus compound by the action of the above-mentioned water-soluble copolymer, the anticorrosion effect is further improved as compared with the conventional one, while reducing the amount of the phosphorus compound used. Succeeded in bringing.

The water-soluble copolymer used in the present invention is a polyelectrolyte, has an effect of suppressing scale components, efficiently disperses phosphorus compounds such as phosphates and zinc salts, and zinc compounds. Since it has an anticorrosion effect, it has the effect of synergistically improving the anticorrosion effect of the phosphorus compound and the zinc compound. The water-soluble copolymer is (meth) acrylic acid and /
Or a monomer unit of a salt thereof, a (meth) acrylamidoalkylsulfonic acid and / or a salt thereof and / or a monomer unit of a (meth) acrylamidearylsulfonic acid and / or a salt thereof, and a substituted (meth) acrylamide monomer A terpolymer including at least a body unit, typically a terpolymer, preferably a monomer unit of (meth) acrylic acid and / or a salt thereof is represented by the following formula (1):
The monomer unit of the alkyl- and / or aryl-sulfonic acid and / or its salt is a substituted (meth) group represented by the following formula (2).
The acrylamide monomer unit is represented by the following formula (3).

[0011]

[Chemical 1]

(In the formula, R ¹ represents a hydrogen atom or a methyl group, and X ¹ represents a hydrogen atom, a monovalent or divalent metal atom, an ammonium group or an organic ammonium group.)

[0013]

[Chemical 2]

(In the formula, R ² represents a hydrogen atom or a methyl group, X ² represents an alkylsulfonic acid group or a salt thereof, or
It represents an aryl sulfonic acid group or a salt thereof, and in the case of a salt, it is a monovalent or divalent metal salt, an ammonium salt or an organic ammonium salt. )

[0015]

[Chemical 3]

(In the formula, R ³ represents a hydrogen atom or a methyl group, and X ³ and X ⁴ each independently represent a hydrogen atom or an alkyl group, but at least one is an alkyl group.)

The organic ammonium salt in the formulas (1) and (2) is preferably a (hydroxy) alkylammonium group having an alkyl or hydroxyalkyl group having 1 to 4 carbon atoms. In the formula (2), X ²
Is an alkylsulfonic acid group or a salt thereof, the alkyl group is preferably an alkyl group having 1 to 8 carbon atoms, and when X ² is an arylsulfonic acid group or a salt thereof, the aryl group is a carbon atom. It is preferably an aryl group or aralkyl group having a number of 8 to 10. Further, one or both of the alkyl groups of X ³ and X ^{4 in} the formula (3) is preferably an alkyl group having 1 to 8 carbon atoms. A preferred weight ratio of these monomer units is (meth) acrylic acid and / or its salt monomer unit: (meth) acrylamide-
Alkyl- and / or aryl-sulfonic acid and / or its salt monomer unit: Substituted (meth) acrylamide monomer unit = 5 to 90: 5 to 50: 5 to 50. Each of the monomer units represented by the formula (1), the formula (2), and the formula (3) may be a single monomer unit represented by each formula or a plurality of monomer units. It may be mixed.

The anticorrosive agent of the present invention is generally provided as a compounded product. For example, from the viewpoint of anticorrosion property and scale preventive property, the anticorrosive agent has the above-mentioned water-soluble copolymer weight relative to the total weight of the anticorrosive composition. The content of the coalescence is preferably 1 to 50% by weight,
It is more preferably 5 to 30% by weight. When the content of the water-soluble copolymer is less than 1% by weight, it may not be possible to expect a sufficient anticorrosion effect, and when it exceeds 50% by weight, the stability of the drug may sometimes be impaired. The cost is also high, which is not preferable. The compounding ratio of the zinc compound is preferably 0.1 to 10% by weight, more preferably 0.2 to 6% by weight, based on the total weight. When the compounding ratio of the zinc compound exceeds 10% by weight, the stability of the drug is impaired, which is not preferable. The compounding ratio of the phosphorus compound is preferably 0.1 to 15% by weight, and more preferably 0.2 to 10% by weight, based on the total weight. As the phosphorus compound, one kind of inorganic or organic phosphorus compound may be blended alone, but the inorganic phosphorus compound and the organic phosphorus compound are 1:10 to 10:
It is preferable to mix them in a weight ratio of 1. Further, the anticorrosive agent of the present invention may contain other components such as a (meth) acrylic acid-based polymer and / or a maleic acid-based polymer, a copper anticorrosive azole compound, and a fungal inhibitor, which will be described in detail later. The anticorrosive agent (blended product) of the present invention usually contains water, and the water content is preferably 30 to 95% by weight, more preferably 50 to 90% by weight, and further preferably 60 to 90% by weight. It is 80% by weight. It is needless to say that the same effect can be obtained by adding the respective components of the anticorrosive agent of the present invention separately to the treated water system, and the present invention can be obtained at the stage where each component is added to the treated water system. It goes without saying that it is preferable that the respective component ratios correspond to those obtained by converting the above-mentioned respective component contents into ratios.

The anticorrosive agent (blended product) of the present invention may contain a fungal inhibitor as described below. The concentration of the anticorrosive agent (blended product) of the present invention usually varies depending on whether the anticorrosive agent contains a fungal inhibitor or not, from the viewpoint of effects and the like. Therefore, the present invention is characterized in that, when the anticorrosive agent of the present invention does not contain a fungal inhibitor, the anticorrosive agent is used by diluting and holding it in a concentration range of 20 to 300 mg / liter in an aqueous system. Water-based anticorrosion method, and
In the case where the anticorrosive agent of the present invention contains a fungal inhibitor, a water-based anticorrosive method comprising using the anticorrosive agent by diluting and holding the anticorrosive agent in a water system within a concentration range of 50 to 1000 mg / liter. provide.

In the above anticorrosion method, the zinc compound is 0.1 to 5 mg / liter, and the phosphorus compound is 0.2 to 1
0 mg / liter, and 1 to 1% of the water-soluble copolymer
It is preferable to keep 50 mg / liter in water from the viewpoint of the effect.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below, but the present invention is not limited thereto. The anticorrosion method of the present invention uses a water-based anticorrosive containing a specific water-soluble copolymer, a phosphorus compound, and a zinc compound to prepare a cooling water treatment system, a wastewater treatment system, an industrial water treatment system, a pure water treatment system, etc. In order to prevent corrosion of metal parts in water treatment systems in general,
It can be applied and preferably exhibits excellent effects when used in a cooling water system.

Preferred monomers used for constituting the (meth) acrylic acid represented by the formula (1) and / or a salt thereof are, for example, methacrylic acid, acrylic acid and sodium thereof. Mention may be made of salt. Examples of the preferable monomer used for constituting the (meth) acrylamido-alkyl- and / or aryl-sulfonic acid represented by the formula (2) and / or its salt monomer unit include 2-acrylamido- Examples thereof include 2-methylpropanesulfonic acid and salts thereof. Moreover, as a preferable monomer used for forming the substituted (meth) acrylamide monomer unit represented by the formula (3), for example, t-butyl acrylamide, t
-Octyl acrylamide, dimethyl acrylamide and the like can be mentioned. In addition, formula (1), formula (2),
In addition to the monomers constituting the monomer unit represented by the formula (3), dicarboxylic acids such as maleic acid, fumaric acid and itaconic acid, salts or anhydrides thereof, hydroxyethyl methacrylate, hydroxypropyl acrylate, etc. (Meth) acrylic acid esters, vinyl acetate, etc. may be used in an amount that does not impair the effect of the anticorrosive agent of the present invention.

The method for synthesizing the above water-soluble copolymer is as follows:
A general method for synthesizing a (meth) acrylic acid copolymer may be used, and for example, the same method as disclosed in JP-A-62-129136 can be used. More specifically, for example, at least a monomer corresponding to the formula (1), the formula (2) and the formula (3) is added with hydrogen peroxide, ammonium persulfate, potassium persulfate, in a solvent such as water or isopropanol. Polymerization may be performed at a predetermined temperature and a predetermined monomer concentration using a polymerization initiator such as benzoyl peroxide. At this time, if necessary, in order to control the molecular weight, the first chloride
Metal salts such as copper, cupric chloride, cupric sulfate, ferrous sulfate and sodium bisulfite may be used.

The water-soluble copolymer contained in the anticorrosive agent of the present invention together with the zinc compound and the phosphorus compound contains at least the monomer units of the above formulas (1), (2) and (3). It is a polymer electrolyte of a specific acrylic acid-based copolymer. In addition to the effect of suppressing scale components, this polymer electrolyte efficiently disperses phosphorus compounds and zinc compounds such as phosphates and zinc salts, and also itself. Has an anticorrosion effect,
It has the effect of synergistically improving the anticorrosion effect of the phosphorus compound and the zinc compound. The weight average molecular weight of this water-soluble copolymer is
1500-25000 are preferable.

In addition to the zinc compound and phosphorus compound and the above-mentioned water-soluble copolymer which is a polyelectrolyte, azole which is an anticorrosive agent for copper-based metals such as copper and copper alloys may be added depending on a treatment water system such as a cooling water system. It is preferable to add a system compound to the anticorrosive agent of the present invention. Examples of such an azole compound include benzotriazole, tolyltriazole, and aminotriazole, and these can be used alone or in combination. Benzotriazole and tolyltriazole are preferred. It is also possible to use other (meth) acrylic acid-based polymers or maleic acid-based polymers in combination in order to enhance the scale suppressing effect. Specific examples of such a polymer include polyacrylic acid, polymaleic acid, a polymer of acrylic acid and 2-acrylamido-2-methylpropanesulfonic acid, and the like. Can also be used. Furthermore, in order to prevent the occurrence of slime and microbial corrosion, it may be preferable to use a fungal inhibitor in combination or in combination with the anticorrosive agent of the present invention. Such fungal inhibitors include, for example, hypochlorites, hypobromite, organic sulfur nitrogen compounds, organic bromine nitrogen compounds, and the like, which may be used alone or in combination. it can. Organic sulfur nitrogen compounds are particularly preferable, and specific examples thereof include 2-methyl-3-isothiazolone, 5-
Examples thereof include chloro-2-methyl-3-isothiazolone, 4,5-dichloro-2-n-octyl-3-isothiazolone, and these may be used alone or in combination. The amount of the azole compound compounded is preferably 0.01 to 10% by weight, based on the total weight of the anticorrosive agent (blended product) of the present invention, from the viewpoint of effects and costs. When another (meth) acrylic acid-based polymer or maleic acid-based polymer is blended, it is preferably 1 to 30% by weight based on the total weight of the anticorrosive agent (blended product) of the present invention. The content of the fungal inhibitor is based on the total weight of the anticorrosive agent (blended product) of the present invention.
It is preferably 1 to 30% by weight from the viewpoint of effects and cost.

The anticorrosive agent of the present invention is usually 20 to 30 in an aqueous system when it does not contain the above-described fungal inhibitor.
It is advisable to dilute and maintain it within the concentration range of 0 mg / liter, and when it contains the above fungal inhibitor,
Normally diluted to a concentration range of 50 to 1000 mg / liter.
It is good to hold and use.

[0027]

EXAMPLES The present invention will be specifically described below with reference to examples, but the examples do not limit the present invention.

Examples 1 and 2 and Comparative Examples 1 to 8 Water-based anticorrosives containing the components shown in Table 1 were prepared and added to test water so that the concentration of each component shown in Table 1 would be adjusted. Prepared and industrial water corrosion test method (JIS-K010
The corrosion rate of mild steel was measured by the mass subtraction method according to 0). That is, a disc on which a test piece was fixed was placed in each sample water and immersed for 7 days while rotating at a constant speed. After 7 days, the test piece was taken out, rust-free and weighed. The corrosion rate was calculated from the difference with the weight of the test piece measured before the start of the test.

[Test Conditions] Test water: pH 7.0, calcium hardness 60 mg / liter (calculated as CaCO ₃ ) Water temperature: 35 ° C. Stirring speed: 150 rpm Test piece: Mild steel (SS400), 30 mm × 50 mm × 1
mm Drug concentration: 100 mg / liter as anticorrosive formulation Test period: 7 days

The test results are shown in Table 1. In Table 1,
"HEDP" is 1-hydroxyethylidene-1,1-diphosphonic acid, "PAA" is polyacrylic acid, "ATE".
“R” is a water-soluble terpolymer used in the present invention, “AAB
“I” is an acrylic acid-based binary copolymer, “PMAA” is polymaleic acid, “MDD” is a unit of corrosion rate, mg / dm ² · day is represented, and “molecular weight” is a weight average molecular weight. . As a feature of each polymer type in Table 1, polyacrylic acid is a water-soluble homopolymer in which X ¹ in the monomer unit of the formula (1) is a hydrogen atom, a water-soluble ternary copolymer used in the present invention. The combined ATER is a water-soluble copolymer composed of the monomer unit of the formula (1) + the monomer unit of the formula (2) + the monomer unit of the formula (3) (weight ratio = 50: 25: 25). The acrylic acid-based binary copolymer AABI is a water-soluble copolymer composed of a monomer unit of the formula (1) + a monomer unit of the formula (2) (weight ratio = 60: 40), and polymaleic acid is maleic acid. It is a water-soluble homopolymer consisting only of acid monomer units. here,
Acrylic acid is used as the monomer corresponding to formula (1), and 2-acrylamide- is used as the monomer corresponding to formula (2).
2-Methylpropanesulfonic acid was used, and t-butylacrylamide was used as the monomer corresponding to formula (3).

[0031]

[Table 1]

From Comparative Example 1 in Table 1, when a phosphorus compound and a zinc compound were used in a ratio of 2: 1 without the combined use of a polymer, at least a minimum anticorrosion effect (MDD of 10 or less) was obtained. It is necessary to add about 5 mg / liter of phosphorus and 2.5 mg / liter of zinc. However, the addition of high concentrations of phosphorus compounds and zinc compounds has many problems such as scale formation of anticorrosion coatings and environmental pollution during discharge from the system.

From Comparative Examples 2 and 3 and Example 1, the phosphorus compound 5
When mgPO ₄ / liter, a zinc compound of 2.5 mgZn / liter and a polymer are used in combination, a very high corrosion inhibiting ability is shown regardless of the kind of the polymer. However, Comparative Example 5
From No. 8, when the phosphorus compound was reduced to 1 mg PO ₄ / liter and the zinc compound was reduced to 0.5 mg Zn / liter, the corrosion rate was significantly increased in the absence of the polymer (Comparative Example 5).
The corrosion rate was still high when used in combination with a normal polymer (Comparative Examples 6 to 8). On the other hand, water-soluble terpolymer ATE
When R was used in combination, the corrosion rate was 1.8 and the anticorrosion effect was particularly excellent (Example 2). From this, it can be seen that the water-soluble terpolymer ATER according to the present invention and the synergistic effect of anticorrosion by the phosphorus compound and the zinc compound are particularly excellent.

[0034]

INDUSTRIAL APPLICABILITY The water-based anticorrosive agent and the anticorrosion method of the present invention have succeeded in suppressing the addition amounts of phosphorus compounds and zinc compounds by using a unique water-soluble copolymer. Therefore, it was possible to enrich the sea, rivers and lakes by phosphorus, reduce environmental pollution due to toxicity of zinc, and reduce costs. In addition, due to the dispersion effect of the unique water-soluble copolymer, scale does not adhere even in the high temperature part of the cooling water system, and when used in the cooling water system device, heat transfer inhibition does not occur in the high temperature part. It also has an excellent effect.

The anticorrosive agent and method of the present invention are applied to various water treatment systems such as a cooling water treatment system, a wastewater treatment system, an industrial water treatment system and a pure water treatment system in order to prevent corrosion of metal members. However, it can be used particularly advantageously in a cooling water system in a large factory.

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) C02F 1/50 531 C02F 1/50 531L 531P 532 532D 532H 532J 540 540B ZAB ZAB 1/76 1/76 A C08K 3/00 C08K 3/00 3/32 3/32 5/3492 5/3492 5/49 5/49 C08L 33/02 C08L 33/02 33/26 33/26 (72) Inventor Hiroshi Takahashi 1-chome Shinsago, Koto-ku, Tokyo No. 2 No. 8 Organo Co., Ltd. F-term (reference) 4D050 AA01 AA08 AA12 AB06 BB03 BB06 4J002 BG011 BG012 BG131 BH002 DD076 DE186 DG046 DH037 EU188 EW127 FD206 FD207 GD00 GD00 GH02 HA04 4K062 ABB12 BB081621 ABB03 BB08 BA09 BA08 BA09 BA08 BA08 BA09 BA08 BA09 BA08 BA09 BA08

Claims (11)

[Claims] 1. A zinc compound and a phosphorus compound, and at least a monomer unit of (meth) acrylic acid and / or a salt thereof, a (meth) acrylamide-alkyl- and / or aryl-sulfonic acid and / or a salt thereof. An anticorrosive agent comprising a water-soluble copolymer comprising a monomer unit and a substituted (meth) acrylamide monomer unit. 2. The zinc compound is 0.1 to 10% by weight,
The anticorrosive agent according to claim 1, which contains 0.2 to 15% by weight of the phosphorus compound and 1 to 50% by weight of the water-soluble copolymer. 3. The phosphorus compound is a combined phosphorus compound having an inorganic phosphorus compound / organic phosphorus compound weight ratio of 1:10 to 10: 1, and the inorganic phosphorus compound is orthophosphoric acid, pyrophosphoric acid, tripolyphosphoric acid, hexametaphosphoric acid, and them. Which is at least one compound selected from the salts, wherein the organophosphorus compound is nitrilotrimethylenephosphonic acid, 1-hydroxyethylidene-1,1-diphosphonic acid, 2-phosphonobutane-1,
The anticorrosive agent according to claim 1 or 2, which is at least one compound selected from 2,4-tricarboxylic acid and salts thereof. 4. A (meth) acrylic acid-based polymer and / or a maleic acid-based polymer is further contained, and the content thereof is
1 to 30% by weight, characterized in that
The anticorrosive agent according to any one of 1. 5. The anticorrosive agent according to claim 1, further comprising an azole compound, the content of which is 0.01 to 20% by weight. 6. The anticorrosive agent according to claim 5, wherein the azole compound is benzotriazole or tolyltriazole. 7. The method according to claim 1, further comprising a fungal inhibitor, the content of which is 1 to 30% by weight.
The anticorrosive agent according to any one of 1. 8. The fungal inhibitor is at least one selected from organic sulfur nitrogen compounds, organic bromine nitrogen compounds, hypochlorite, and hypobromite. Anticorrosive. 9. An anticorrosion method comprising using the anticorrosive according to any one of claims 1 to 6 in a water system at a retention concentration of 20 to 300 mg / liter. 10. An anticorrosion method, which comprises using the anticorrosive according to claim 7 or 8 in an aqueous system at a retention concentration of 50 to 1000 mg / liter. 11. The zinc compound is 0.1 to 5 mg / liter, the phosphorus compound is 0.2 to 10 mg / liter,
And the anticorrosion method according to claim 9 or 10, wherein 1 to 50 mg / liter of the water-soluble copolymer is held in water.