Corrosion prevention method for water system

Abstract

Techniques are provided relating to corrosion prevention in water systems for better inhibition of corrosion of metals in contact with water. A corrosion prevention method for an aqueous system for inhibiting corrosion of a metal in contact with the aqueous system includes using a phosphorus compound, a film-forming amine, and a copolymer of a (meth) acrylic monomer having a weight average molecular weight of 500 to 100,000 and a sulfonic acid group-containing monomer in the aqueous system. A metal corrosion inhibitor comprising a phosphorus compound, a film-forming amine, and a low molecular weight polymer having a weight average molecular weight of 500 to 100,000, and a corrosion prevention method for a water system comprising using the metal corrosion inhibitor, for inhibiting corrosion of a metal in contact with water.

Description

Technical Field

[0001] The present invention relates to, for example, an anticorrosion method for a water system, a metal corrosion inhibitor, a water treatment agent for metal anticorrosion, a water treatment agent, and an anticorrosion method for a water system including inhibiting corrosion of a metal in contact with water by using these reagents. Background Art

[0002] Metal components (such as heat exchangers, reaction vessels, and pipes made of carbon steel, copper, or copper alloy, etc.) installed in a water system (such as an open recirculating cooling water system, etc.) are corroded due to contact with the water in the water system. Therefore, anticorrosion treatment is usually carried out by adding chemical reagents.

[0003] For example, in order to inhibit corrosion of heat exchangers, reaction vessels, and pipes made of carbon steel in a cooling water system, a technique using film-forming amines is considered.

[0004] For example, Non-Patent Document 1 proposed a method using film-forming amines as another method for inhibiting corrosion. The method described in Non-Patent Document 1 is mainly applied to the corrosion inhibition effect of iron-based components in a boiler water system. In Non-Patent Document 1, as the anticorrosion mechanism based on film-forming amines, it is disclosed that by adsorbing film-forming amines onto the metal surface via amino groups to form a dense monolayer or multilayer film, the contact between the metal and water is prevented, thereby inhibiting metal corrosion.

[0005] For example, Patent Document 1 proposed the following anticorrosion method: by coexisting film-forming amines and an M alkalinity component in a cooling water system to form a corrosion-resistant coating on the surface of a metal component, corrosion of the metal component in contact with the cooling water system is inhibited, wherein a neutralizing amine is used as the M alkalinity component, and in the initial treatment of forming the corrosion-resistant coating, the M alkalinity of the cooling water system is adjusted to 90 mg / L or more in terms of CaCO3.

[0006] [Citation List]

[0007] [Patent Document]

[0008] Patent Document 1: WO 2019 / 078104

[0009] [Non-Patent Document]

[0010] Non-Patent Document 1: Corrosion Center News No.054 (August 2010) Water Treatment Technology (1) “Corrosion / Anticorrosion in Boilers and surrounding Equipment”, Fumio Kawamura Summary of the Invention

[0011] Problems to be Solved by the Invention

[0012] However, generally, the corrosion inhibition strength of the film-forming amine itself is weak. In addition, there is a situation where the corrosivity of materials is a concern during the use of the film-forming amine as a scale inhibitor in an open recirculating cooling water system.

[0013] Therefore, the main object of the present invention is to provide a technique related to corrosion prevention in a water system for better suppressing the corrosion of metals in contact with water.

[0014] Solutions for Solving the Problems

[0015] As a result of in-depth research, the present inventors have found that by using a phosphorus compound, a film-forming amine, and a polymer (preferably a (meth)acrylic acid copolymer and / or a low molecular weight polymer) in combination, the corrosion of metals in contact with water can be better suppressed. In addition, the present inventors have found that by using a film-forming amine and a polymer in combination, the metal corrosion prevention based on the phosphorus compound can be better enhanced. That is, the present inventors have completed the following invention.

[0016] The present invention provides a corrosion prevention method for a water system for suppressing the corrosion of metals in contact with the water system, the method comprising using a phosphorus compound, a film-forming amine, and a copolymer of (meth)acrylic acid monomers and sulfonic acid group-containing monomers having a weight average molecular weight of 500 to 100,000 in an amount greater than 5 mg / L in the water system.

[0017] In addition, the present invention provides a metal corrosion inhibitor comprising a phosphorus compound, a film-forming amine, and a low molecular weight polymer having a weight average molecular weight of 500 to 100,000,

[0018] wherein the polymer is included and used in an amount greater than 5 mg / L.

[0019] In addition, the present invention provides a water treatment agent for metal corrosion prevention, which comprises at least one of a phosphorus compound, a film-forming amine, or a copolymer of (meth)acrylic acid monomers and sulfonic acid group-containing monomers having a weight average molecular weight of 500 to 100,000, wherein when used for metal corrosion prevention in a water system, a phosphorus compound, a film-forming amine, and a copolymer of (meth)acrylic acid monomers and sulfonic acid group-containing monomers are used in combination in the water system, and the copolymer is included and used in an amount greater than 5 mg / L.

[0020] In addition, the present invention provides a water treatment agent comprising a film-forming amine and / or a copolymer of (meth)acrylic acid monomers having a weight average molecular weight of 500 to 100,000 and monomers containing a sulfonic acid group. When used in a water system, the water treatment agent is used by combining the film-forming amine with the copolymer of (meth)acrylic acid monomers and monomers containing a sulfonic acid group to enhance metal corrosion prevention based on phosphorus compounds, and

[0021] the copolymer is included in an addition amount greater than 5 mg / L for use.

[0022] The copolymer may be a copolymer of (meth)acrylic acid monomers and monomers containing an amide group or a hydroxyl group and a sulfonic acid group.

[0023] The film-forming amine may be an aliphatic amine compound.

[0024] The phosphorus compound may be a phosphonic acid compound.

[0025] When using the film-forming amine, the copolymer of (meth)acrylic acid monomers and monomers containing a sulfonic acid group can be used in combination in the water system.

[0026] The water system may be a cooling water system.

[0027] The present invention can also provide an anti-corrosion method for a water system, which is used to inhibit the corrosion of metals in contact with water. The method includes using the above-mentioned reagent.

[0028] Effects of the Invention

[0029] According to the present invention, a technique related to anti-corrosion in a water system can be provided, which is used to better inhibit the corrosion of metals in contact with water. It should be noted that the effects of the present invention are not necessarily limited to the effects described herein and may be any of the effects described herein. Description of the Drawings

[0030] Figure 1 is a schematic diagram showing an example of a water system used in the method of this embodiment, for example, an example of a circulating cooling water system having a cooling tower, and the present invention is not limited thereto.

[0031] Figure 2 is a schematic diagram of a rotating corrosion test device used in the tests conducted in this specification. Detailed Description

[0032] Hereinafter, preferred embodiments for carrying out the present invention will be described. It should be noted that the following embodiments are examples of representative embodiments of the present invention, and the scope of the present invention should not be construed narrowly only by this example. Further, in this specification, unless otherwise specified, percentages are expressed in terms of mass (mass / mass %). Further, the upper limit value (hereinafter) and the lower limit value (above) of each numerical range can be freely combined as needed.

[0033] 1. Metal anticorrosion method for water systems according to this embodiment

[0034] The present invention can provide an anticorrosion method for water systems, which is used to inhibit the corrosion of metals in contact with water systems. The method includes using a phosphorus compound, a film-forming amine, and a polymer in the water system. The anticorrosion method for water systems can be an anticorrosion treatment method for water systems. The polymer is preferably a low molecular weight and / or (meth)acrylic polymer. More specifically, examples include low molecular weight polymers, (meth)acrylic polymers, and low molecular weight (meth)acrylic polymers. It is preferred to select one or more of these. More preferably, the polymer is a copolymer of (meth)acrylic monomers and sulfonic acid group-containing monomers having a weight average molecular weight of 500 to 100,000.

[0035] According to the present invention, a technique related to anticorrosion in water systems can be provided, which is used to better inhibit the corrosion of metals in contact with water. Further, according to the present invention, by combining the use of a film-forming amine and a polymer, a technique that can better enhance the metal anticorrosion based on the phosphorus compound can be provided, thereby enabling the provision of a technique for metal anticorrosion in water systems that can reduce the usage amount of the phosphorus compound or phosphorus. According to the present invention, a technique that can enhance the anticorrosion strength of metal materials in water systems or cooling water systems (preferably circulating cooling water, more preferably an open circulating cooling water system) can be provided. Further, according to the present invention, a technique that can enhance the anticorrosion strength of metal materials during water system descaling, thereby enabling the extension of the lifespan of metal materials, can be provided.

[0036] In the prior art, a film-forming amine is added to a water system for use in the anticorrosion of metal components included in the water system. For example, corrosion inhibitors for steam in boilers have been proposed, or the anticorrosion of metal materials is enhanced by combining a corrosion inhibitor for copper and acid consumption. Further, the use of a film-forming amine as an on-line scale remover in an open circulating cooling water system has also attracted attention. However, the anticorrosion strength of the film-forming amine itself is weak, and there are cases where the corrosiveness of the material is a concern during the use of the film-forming amine as a scale remover.

[0037] On the other hand, in the present invention, when a film-forming amine is used as a scale inhibitor (preferably an in-line scale inhibitor), further using a low molecular weight and / or (meth)acrylic polymer can provide a technique that can enhance the anticorrosion strength and achieve a corrosion inhibition effect on the material to be descaled.

[0038] In the present specification, "in-line" in "in-line scale inhibitor" means that scale removal is carried out by operating the water system without stopping (for example, continuous operation or circulation through a circulating water system, etc.), and the operation of the water system (such as plant operation, etc.).

[0039] Furthermore, in the present embodiment, by operating the water system, during the operation of the water system, the chemical reagent to be used or the water containing the chemical reagent is brought into contact with the components of the water system (such as metal components, internal piping, etc.). Therefore, in addition to the anticorrosion effect, a scale inhibition effect can also be exerted.

[0040] Now, the present embodiment will be described in detail below.

[0041] In the present embodiment, the object to be protected against corrosion is a metal material, and there is no particular limitation thereto. Examples of such metal materials include one or more selected from the group consisting of carbon steel, copper, galvanized steel, zinc, aluminum, aluminum alloy, stainless steel, etc., and their alloys. Furthermore, among metal materials, iron-based materials are preferred. Examples of such iron-based materials include common iron materials (such as pure iron, carbon steel, and cast iron, etc.), and more preferably carbon steel materials such as carbon steel pipes (such as STB steel pipes) commonly used for boilers and heat exchangers. In JIS G 0203, it is stipulated that the carbon content of carbon steel materials is in the range of 0.02 mass% to about 2 mass%. More specifically, among carbon steels, carbon steel with a carbon content of 0.25 mass% or less is called low-carbon steel, carbon steel with a carbon content of 0.25 to 0.6 mass% is called medium-carbon steel, and carbon steel with a carbon content of 0.6 mass% or more is called high-carbon steel. Since low-carbon steel to medium-carbon steel are widely used, carbon steel containing 0.6 mass% or less is also called ordinary steel. In addition, it is said that the carbon content of cast iron exceeds 2 mass%. In the present embodiment, among these, ordinary steel, low-carbon steel, and medium-carbon steel, and more preferably low-carbon steel, can better exert the anticorrosion effect.

[0042] The object to be preferably subjected to the anticorrosion treatment in the present embodiment is preferably a metal material in contact with water or a metal component using a metal material in contact with water.

[0043] Examples of the positions or devices in the water system where metal materials or metal components are used include various pipes and conduits such as water supply pipes, pumps, flow paths, heat exchangers, and refrigerators, etc., and the position or device can be one or more selected from these. More specifically, these positions or devices, or the metal products or parts of these positions or devices, are the objects to be preferably subjected to the anticorrosion treatment in the present embodiment.

[0044] 1-1. Phosphorus compound

[0045] The phosphorus compound used in this embodiment is preferably a phosphorus oxyacid compound having at least P(=O)(-OH). Examples of preferred phosphorus compounds include phosphonic acid compounds, hypophosphonic acid compounds, phosphoric acid compounds, etc., and one or more than two thereof can be selected from these. These compounds can be in the form of salts. The salts are not particularly limited, and examples thereof include salts of alkali metals (such as sodium and potassium, etc.), alkaline earth metals (such as calcium and magnesium, etc.), etc., and one or more than two thereof can be used.

[0046] The phosphorus compound is preferably a compound that can be used in a water system (preferably for water treatment such as anti-corrosion, etc.), more preferably a water-soluble compound. The phosphorus compound preferably has a scale inhibition effect and is preferably a compound that can be used as a scale inhibitor for membranes. In addition, the phosphorus compound is preferably a compound that can capture metal ions (such as Ca and Al, etc.) and is preferably a compound that can be used as a phosphoric acid compound scale inhibitor or a phosphonic acid compound scale inhibitor. The form of the phosphorus compound in this embodiment is not particularly limited and can be liquid, solid or semi-solid, preferably liquid because it is easy to handle. In addition, the phosphorus compound used in this embodiment can be a commercially available product or a compound obtained by a known manufacturing method. One or more than two thereof can be used.

[0047] Among the phosphorus compounds, from the viewpoint of exerting a better anti-corrosion effect, an organic phosphorus compound is preferred, and a phosphonic acid compound is more preferred. When using an organic phosphorus compound (preferably a phosphonic acid compound), the organic phosphorus compound can be used in combination with a phosphoric acid compound.

[0048] The phosphonic acid compound is preferably a compound having at least a phosphonic acid group, preferably an organic phosphorus compound. Examples of the phosphonic acid compound include 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC, also known as 2-phosphono-1,2,4-tricarboxybutane), 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP, also known as: 1-hydroxyethane-1,1-diphosphonic acid), 2-hydroxyethylidene diphosphonic acid, aminotrimethylene phosphonic acid, ethylenediamine tetra(methylene phosphonic acid), diethylenetriamine pentamethylene phosphonic acid, etc., and salts thereof. One or more than two thereof can be selected from these examples. Among them, 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC) and / or 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP) are preferred. One or more than two thereof can be selected from these.

[0049] A phosphinic acid compound is a compound having at least a phosphinic acid group. As phosphinates, examples include bis(poly-2-carboxyethyl)phosphinic acid and phosphono carboxylic acid copolymers, etc., and their salts. Among them, phosphono carboxylates are preferred. One or more than two can be selected from these.

[0050] One or more than two can be appropriately selected from the above examples of phosphorus compounds.

[0051] The phosphoric acid compound is preferably a compound containing at least a phosphoric acid group, preferably a compound that can generate phosphate ions in the water of a water system, and more preferably an inorganic phosphoric acid compound. Examples of the phosphoric acid compound include phosphorus, phosphoric anhydride, phosphoric acid (also called orthophosphoric acid); polymeric phosphoric acids (for example, chain polyphosphoric acids such as pyrophosphoric acid, tripolyphosphoric acid, orthopolyphosphoric acid, and decapolyphosphoric acid; and cyclic polyphosphoric acids such as hexametaphosphoric acid; and their salts). One or more than two can be selected from these. The number of phosphorus atoms in the phosphoric acid compound is not particularly limited, but for example, it is 1 to 10, and examples include orthophosphoric acid (1 phosphorus atom) and pyrophosphoric acid (2 phosphorus atoms).

[0052] When using a phosphorus compound in a water system, the use concentration (mg PO4 / L, hereinafter referred to as "mg / L") is not particularly limited, but is preferably 0.1 to 10 mg / L, and more preferably 3 to 6 mg / L. The phosphorus compound is preferably added in such a way as to obtain such a concentration. In a more preferred mode, when using a phosphinic acid compound in a water system, the use concentration (mg PO4 / L) is preferably 0.1 to 10 mg / L, and more preferably 3 to 6 mg / L.

[0053] In addition, as the use concentration of the above phosphorus compound, etc., the preferred upper limit value and the preferred lower limit value in the "usage amount of the phosphorus compound (preferably phosphinic acid compound) in the water system" in the following part "1-4" can be appropriately adopted.

[0054] In addition, the concentration (mg PO4 / L) of the phosphorus compound can be determined by the molybdenum blue (ascorbic acid reduction) method (JIS K0102 46.1.1).

[0055] 1-2. Film-forming amine

[0056] The film-forming amine used in this embodiment is not particularly limited, but is preferably an amine that can form a corrosion-resistant coating having an effective corrosion inhibition effect on a metal material in contact with water. As the film-forming amine, a film-forming amine that is usually used as a corrosion inhibitor in a water system such as a boiler water system or a cooling water system can be used, or the film-forming amine can be a film-forming amine commonly used in a water system. As the film-forming amine, one or more of aliphatic amine compounds (for example, aliphatic monoamine compounds and aliphatic diamine compounds, etc.) can be used. In this specification, "aliphatic amine compound" can be expressed as "aliphatic amine". Since the film-forming amine is not easily soluble in water, the film-forming amine can be used by dissolving the film-forming amine in oil or by dispersing the film-forming amine in water as an emulsion.

[0057] In this embodiment, by using at least a film-forming amine and a polymer in combination, there are the following advantages: the anti-corrosion strength can be enhanced, and the corrosion inhibition effect on a material (such as a metal material) undergoing scale removal can be achieved. In addition, when the film-forming amine is used as an on-line scale remover, there is an advantage that a better anti-corrosion effect can be exerted.

[0058] The aliphatic amine compound (aliphatic amine) preferably has 1 or 2 nitrogen atoms and has an aliphatic group bonded to at least 1 nitrogen atom. The aliphatic amine compound (aliphatic amine) is not particularly limited, but examples include aliphatic amines, their salts, and their derivatives. One or more of these can be used. More preferred examples include aliphatic monoamine compounds and aliphatic diamine compounds, etc., and one or more compounds selected from these can be used.

[0059] The aliphatic amine compound (aliphatic amine) is preferably a long-chain aliphatic amine compound (long-chain aliphatic amine). The number of carbon atoms in the long-chain aliphatic group is not particularly limited as long as a corrosion-resistant coating can be formed, and is preferably 10 to 22, more preferably 12 to 20, and further preferably 16 to 18. When the number of carbon atoms is 10 or more, a film can be easily formed on a metal member, and the corrosion inhibition effect function can be exerted well. When the number of carbon atoms is 22 or less, the operability during chemical injection is excellent, and there is a tendency to be improved.

[0060] The aliphatic group constituting the aliphatic amine compound (aliphatic amine) may contain an unsaturated bond. In addition, the hydrogen part of the amino group constituting the aliphatic amine compound may be appropriately replaced with a hydrocarbon group such as a methyl group or an ethyl group. Further, the aliphatic amine may be a fatty acid salt (for example, a mixed amine compound, etc.). In this case, examples of the fatty acid part constituting the fatty acid salt include one or more selected from the group consisting of oleic acid, lauric acid, stearic acid, and the like. When the aliphatic amine compound is a fatty acid salt, the raw material may be, for example, one or more selected from the group consisting of animal oil, vegetable oil, and microbial oil, preferably animal oil and vegetable oil.

[0061] Preferred specific examples of the aliphatic amine compound (aliphatic amine) include saturated aliphatic amine compounds (alkylamines), unsaturated aliphatic amine compounds (alkynylamines), mixed amine compounds (for example, coconut oil amine, hydrogenated tallow amine, etc.), and alkylene oxide adducts of aliphatic amine compounds, etc. One or more selected from these can be used. Examples of the "alkylene oxide adduct of aliphatic amine compound" include those obtained by addition polymerization of ethylene oxide, propylene oxide, etc. with an aliphatic mixed amine, etc.

[0062] The aliphatic group in the aliphatic amine compound may be acyclic or cyclic. More specifically, it may be chain-like (straight-chain, branched-chain) or alicyclic (non-aromatic ring). However, a chain-like form is preferred. The aliphatic group is preferably a saturated aliphatic group, more preferably an alkyl group or an alkylene group, which may have appropriate substituents.

[0063] Examples of the structure of the aliphatic monoamine compound include, but are not limited to, "aliphatic group - amino", etc. Examples of the aliphatic diamine compound include, but are not limited to, the following compounds: a compound in which at least one hydrogen atom of the amino group in the compound is replaced with an aliphatic group and a compound in which a divalent aliphatic group exists between the nitrogen atom of one amino group and the nitrogen atom of the other amino group. Examples of the aliphatic diamine compound include "amino - divalent aliphatic group - amino", and preferably at least one amino group is "aliphatic group - amino". Examples include "RR’N - divalent aliphatic group - NH2", such as trimethylene diamine (also called "diaminopropane"). The divalent aliphatic group may be chain-like (straight-chain, branched-chain) or alicyclic, but is preferably straight-chain. "Amino" refers to a monovalent functional group (-NH2, -NHR, -NRR’) obtained by removing hydrogen from ammonia, a primary amine, or a secondary amine. R and R’ may each be hydrogen, or one of R and R’ may be hydrogen and the other may be an alkyl group, or R and R’ may each be the same or different alkyl groups.

[0064] The divalent aliphatic group is preferably a divalent saturated or unsaturated hydrocarbon group, more preferably a divalent saturated hydrocarbon group, and further preferably a chain-like alkylene group having 1 to 4 carbon atoms (preferably a methylene group or an ethylene group). Examples include -(CH2)n - wherein n = 1 to 4), and diethylene (n = 2) and triethylene (n = 3), etc.

[0065] Examples of the aliphatic amine compound (preferably long-chain aliphatic amine compound) include saturated aliphatic monoamine compounds (e.g., dodecylamine, tridecylamine, tetradecylamine, heptadecylamine, hexadecylamine, octadecylamine, nonadecylamine, eicosylamine, docosylamine, etc.), unsaturated aliphatic monoamine compounds (e.g., oleylamine, ricinoleylamine, linoleylamine, linolenylamine, etc.), mixed monoamine compounds (e.g., coconut oil amine, hydrogenated tallow amine, etc.); diamino compounds having an aliphatic group in the amino group (e.g., alkylpropylenediamine (the alkyl preferably has 16 to 18 carbon atoms), N,N-diethyl-1,3-propylenediamine, N-oleyl-1,3-diaminopropane, N-tallow-1,3-diaminopropane, N-coco-1,3-diaminopropane, etc.); alkylene oxide adducts, such as N-tallow-1,3-diaminopropane-ethylene oxide adduct, etc. One or more than two selected from these can be used.

[0066] Among the above-mentioned aliphatic amine compounds (aliphatic amines), aliphatic monoamine compounds and / or aliphatic diamine compounds are preferred, aliphatic diamine compounds are more preferred, and long-chain aliphatic compounds are further preferred.

[0067] When using a film-forming amine (preferably an aliphatic amine compound, more preferably an aliphatic diamine compound) in a water system, the use concentration (mg / L, hereinafter referred to as "mg / L") is not particularly limited, but is preferably 5 to 70 mg / L, more preferably 10 to 50 mg / L. The film-forming amine is preferably added in such a way as to obtain such a concentration. In addition, this use concentration can be the use concentration during on-line use. In a more preferred mode, when using an aliphatic diamine compound in a water system, the use concentration is more preferably 5 to 70 mg / L, further preferably 10 to 50 mg / L.

[0068] In addition, as the use concentration when using the above-mentioned film-forming amine, etc., the preferred upper limit value and the preferred lower limit value in the "usage amount of the film-forming amine (preferably an aliphatic amine compound, more preferably an aliphatic diamine compound) in the water system" in the following section "1-4" can be appropriately adopted.

[0069] 1-3. Polymer

[0070] The polymer used in the present embodiment is not particularly limited, but an organic polymer compound that can preferably be used in an aqueous system is more preferred, and a low molecular weight polymer and / or a water-soluble polymer are even more preferred. Among the polymers used in the present embodiment, (meth)acrylic polymers are preferred, and (meth)acrylic polymers containing a sulfonic acid group in the molecule are more preferred, and (meth)acrylic polymers containing a sulfonic acid group in the molecule are even more preferred. Among them, AA / AMPS polymers and AA / HAPS polymers are preferred. In addition, the polymer used in the present embodiment may be a homopolymer obtained from the same monomer, but a copolymer obtained from different monomers is preferred. As the polymer used in the present embodiment, a polymer used as a scale inhibitor in a cooling water system can be preferably used. The form of the polymer salt is not particularly limited, but a salt that can convert monomers and polymers into water-soluble salts is preferred. Examples include alkali metal salts such as sodium and potassium, alkaline earth metal salts such as calcium and magnesium, and ammonium salts such as ammonium or primary to tertiary amines. One or more of these can be used.

[0071] Examples of the polymer used in the present embodiment include homopolymers or copolymers obtained by polymerizing or copolymerizing one or more monomers selected from the group consisting of: (meth)acrylic compounds such as (meth)acrylic acid (acrylic acid and / or methacrylic acid) and 2-hydroxyethyl methacrylate (HEMA); sulfonic acid group-containing monomers such as 1-propanesulfonic acid (HAPS), 2-acrylamido-2-methylpropanesulfonic acid (AMPS), styrenesulfonic acid (SS), and isoprenesulfonic acid (IPS); isobutene (IB); and maleic acid. It should be noted that monomers of (meth)acrylic compounds other than (meth)acrylic acid can be used. For example, (meth)acrylic compounds having an ester, a hydroxyl group, or an amino group can be used, but (meth)acrylic acid is preferred.

[0072] Among the above polymers, (meth)acrylic polymers are preferred, and copolymers of (meth)acrylic monomers and sulfonic acid monomers are more preferred. More preferred specific examples include homopolymers or copolymers obtained by polymerizing or copolymerizing one or more monomers selected from the group consisting of: (meth)acrylic acid (preferably acrylic acid (AA)); 2-hydroxy-3-(allyloxy)-1-propanesulfonic acid (HAPS) and 2-acrylamido-2-methylpropanesulfonic acid (AMPS).

[0073] The weight-average molecular weight of the polymer (preferably a (meth)acrylic polymer) is not particularly limited, but a low molecular weight is preferred. The lower limit value is preferably 500 or more, more preferably 1,000 or more, more preferably 4,000 or more, and more preferably 5,000 or more. The upper limit value is preferably 100,000 or less, more preferably 50,000 or less, more preferably 30,000 or less, and more preferably 20,000 or less. More specifically, the more preferred numerical range is more preferably from 500 to 100,000, more preferably from 1,000 to 50,000, more preferably from 4,000 to 30,000, and more preferably from 5,000 to 20,000.

[0074] The weight-average molecular weight of the polymer in this specification can be obtained by gel permeation chromatography (GPC analysis) using a standard substance, and when sodium polyacrylate is used as the standard substance, the weight-average molecular weight is based on the value of sodium polyacrylate.

[0075] 1-3-1. (Meth)acrylic polymer

[0076] The polymer used in this embodiment is preferably a (meth)acrylic polymer, more preferably a (meth)acrylic copolymer. More specifically, the polymer is preferably a copolymer of a (meth)acrylic monomer and a sulfonic acid group-containing monomer, and further preferably a copolymer of a (meth)acrylic monomer and a monomer containing an amide group and a sulfonic acid group. The monomer ratio (mole ratio (mol%)) between the (meth)acrylic monomer and the sulfonic acid group-containing monomer in the (meth)acrylic copolymer is preferably 99 to 1:1 to 99. The (meth)acrylic copolymer preferably has a low molecular weight.

[0077] <(meth)acrylic monomer>

[0078] Examples of the (meth)acrylic monomer are not particularly limited, but include (meth)acrylic acid and its salts, and one or more selected therefrom can be used. In this embodiment, “(meth)acrylic acid” means at least one selected from the group consisting of “acrylic acid” and “methacrylic acid”. Among them, acrylic acid or its salt is preferred. In addition, when the (meth)acrylic monomer used in this embodiment contains a sulfonic acid group, it is preferred to use this monomer as the sulfonic acid monomer. The (meth)acrylic monomer used in this embodiment is more preferably a monomer other than the (meth)acrylic monomer containing a sulfonic acid group.

[0079] <sulfonic acid monomer>

[0080] The sulfonic acid monomer is not particularly limited. However, from the viewpoint of achieving a better anti-corrosion effect, a sulfonic acid group-containing monomer is preferred, and a monomer in which the monomer is an unsaturated monomer is more preferred. Examples of the sulfonic acid monomer include, but are not limited to, monoethylenically unsaturated sulfonic acid monomers and their salts, etc., among which monoethylenically unsaturated sulfonic acid monomers are preferred.

[0081] Examples of the sulfonic acid monomer include monomers having an amide group and a sulfonic acid group (preferably having 6 to 9 carbon atoms), monomers containing a hydroxyl group and a sulfonic acid group (preferably having 6 to 9 carbon atoms), sulfonates of aliphatic conjugated dienes (preferably having 4 to 15 carbon atoms), and their salts, etc. One or more than two can be selected from these groups. Among them, monomers having an amide group and a sulfonic acid group (preferably having 6 to 9 carbon atoms) and monomers containing a hydroxyl group and a sulfonic acid group (preferably having 6 to 9 carbon atoms) are preferred. In addition, the "sulfonic acid group" of the monomer can be a sulfonic acid group optionally having a substituent, such as an alkylsulfonic acid group. The number of carbon atoms in the "alkyl" of the alkylsulfonic acid group is preferably 1 to 8, and more preferably a methylpropanesulfonic acid group (also known as a tert-butylsulfonic acid group). This allows for a better anti-corrosion effect to be exerted.

[0082] Examples of the monomer having an amide group and a sulfonic acid group include (meth)acrylamidoalkylpropanesulfonic acid and crotonamidoalkylpropanesulfonic acid, etc. More specifically, examples include 2-acrylamido-2-methylpropanesulfonic acid (AMPS), 3-acrylamido-3,3-dimethylpropanesulfonic acid, 2-methacrylamido-2-methylpropanesulfonic acid, 3-methacrylamido-3,3-dimethylpropanesulfonic acid, etc., and their salts, etc. One or more than two can be selected from these groups.

[0083] Examples of the monomer containing a hydroxyl group and a sulfonic acid group include 3-allyloxy-2-hydroxy-1-propanesulfonic acid (HAPS), 3-methacryloyloxy-2-hydroxypropanesulfonic acid, 3-allyloxy-1-hydroxypropane-2-sulfonic acid, 3-methacryloyloxy-1-hydroxypropane-2-sulfonic acid, and their salts. One or more than two can be selected from these groups.

[0084] Examples of the sulfonate of aliphatic conjugated dienes include sulfonates of 1,3-butadiene and sulfonates of 2,3-dimethyl-1,3-butadiene, etc. One or more than two can be selected from these groups.

[0085] Examples of more preferred sulfonic acid monomers include sulfonic acid group-containing unsaturated monomers such as (meth)acrylamidomethylpropanesulfonic acid, 3-allyloxy-2-hydroxypropanesulfonic acid, (meth)allylsulfonic acid, vinylsulfonic acid, styrenesulfonic acid, and 2-sulfoethyl methacrylate, and salts thereof. One or more than two kinds can be used selected from these groups. Among them, at least one monomer selected from the group consisting of 2-acrylamido-2-methylpropanesulfonic acid (AMPS) and 3-allyloxy-2-hydroxypropanesulfonic acid (HAPS) is preferred, and AMPS and / or HAPS are more preferred. By using these, a better anti-corrosion effect can be exerted.

[0086] <Manufacturing example of (meth)acrylic acid copolymer>

[0087] (Meth)acrylic acid copolymers can be manufactured by a known manufacturing method. Preferred copolymers are polymers obtained by copolymerizing (i) (meth)acrylic acid monomers and (ii) one or more than two kinds of sulfonic acid monomers selected from the group consisting of monomers containing an amide group and a sulfonic acid group and monomers containing a hydroxyl group and a sulfonic acid group, etc. at a predetermined mass usage ratio. It should be noted that any monomer can be used within the range that does not impair the effects of the present invention.

[0088] A more preferred (meth)acrylic acid copolymer is a polymer obtained by copolymerizing (i) acrylic acid monomers and (ii) at least one sulfonic acid monomer selected from the group consisting of 2-acrylamido-2-methylpropanesulfonic acid and 3-allyloxy-2-hydroxypropanesulfonic acid at a predetermined mass usage ratio. Examples of further preferred (meth)acrylic acid copolymers include one or more than two kinds selected from the group consisting of copolymers of acrylic acid monomers and 2-acrylamido-2-methylpropanesulfonic acid monomers and copolymers of acrylic acid monomers and 3-allyloxy-2-hydroxypropanesulfonic acid monomers. In this case, a more preferred predetermined molar ratio between the (meth)acrylic acid monomer and the sulfonic acid monomer is, for example, 1 to 99:99 to 1. As this molar ratio, the molar ratio in <Molar ratio (mol%) in (meth)acrylic acid copolymer> described later can be appropriately adopted. This can obtain a polymer that exerts a better anti-corrosion effect.

[0089] <Molar ratio (mol%) between (meth)acrylic acid monomer and sulfonic acid monomer>

[0090] The molar ratio (mol%: when the total amount of the two is 100) between the (meth)acrylic acid monomer and the sulfonic acid monomer in the copolymer of the component (A), i.e., the (meth)acrylic acid monomer and the sulfonic acid monomer, is not particularly limited. As the preferred lower limit value of the (meth)acrylic acid monomer, the molar ratio is preferably 10 or more, more preferably 40 or more, further preferably 50 or more, more preferably 60 or more, more preferably 70 or more, more preferably 75 or more, more preferably 80 or more. In addition, as the preferred upper limit value of the (meth)acrylic acid monomer, it is preferably 99 or less, more preferably 98 or less, further preferably 95 or less, more preferably 93 or less, and further preferably 90 or less. As a more preferred numerical range of the molar ratio between the acrylic acid monomer and the sulfonic acid monomer, it is more preferably 50-99:50-1, further preferably 60-95:40-5, and more preferably 75-95:25-10. By setting the copolymer of the component (A) to the above molar ratio, a better anti-corrosion effect can be exerted. For this molar ratio, the respective molar ratios (%) between the (meth)acrylic acid monomer and the sulfonic acid monomer that constitute copolymers such as AA / AMPS polymer and AA / HAPS polymer described below can be appropriately adopted.

[0091] As a more preferred mode of the molar ratio of the copolymer, the molar ratio (mol%) between the (meth)acrylic acid monomer and the sulfonic acid monomer containing an amide group and / or a hydroxyl group in the copolymer of the (meth)acrylic acid monomer and the sulfonic acid monomer containing an amide group and a hydroxyl group is more preferably 60-95:40-5, and more preferably 75-90:25-10. By setting the molar ratio in this way, a better anti-corrosion effect can be exerted. For this molar ratio, the preferred lower limit value and the preferred upper limit value in the above-mentioned "molar ratio between the (meth)acrylic acid monomer and the sulfonic acid monomer" can be appropriately adopted.

[0092] In addition, as a more preferred mode of the molar ratio of the copolymer, in the case of AA / AMPS polymer or AA / HAPS polymer, the AA / AMPS ratio and the AA / HAPS ratio (mol%) (AA: AMPS or HAPS) are preferably (AA) 50-99:50-1, further preferably (AA) 60-95:40-5, and more preferably (AA) 75-90:25-10. By setting the molar ratio in this way, a better anti-corrosion effect can be exerted. For this molar ratio, the preferred lower limit value and the preferred upper limit value in the above-mentioned "molar ratio between the (meth)acrylic acid monomer and the sulfonic acid monomer" can be appropriately adopted.

[0093] <Weight-average molecular weight of the (meth)acrylic acid copolymer>

[0094] The weight-average molecular weight of the copolymer of the (meth)acrylic acid monomer and the sulfonic acid monomer measured by GPC is not particularly limited, but as a preferred lower limit value, it is preferably 500 or more, more preferably 1,000 or more, further preferably 2,000 or more, more preferably 3,000 or more, further preferably 4,000 or more, and more preferably 5,000 or more. As a preferred upper limit value, it is preferably 100,000 or less, more preferably 50,000 or less, further preferably 40,000 or less, more preferably 30,000 or less, and more preferably 20,000 or less. The preferred numerical range of the (meth)acrylic acid monomer and the sulfonic acid monomer is more preferably 4,000 to 30,000, and desirably 5,000 to 20,000. In addition, as the preferred weight-average molecular weight of the AA / AMPS polymer and the AA / HAPS polymer, the above-mentioned preferred lower limit value and upper limit value can be appropriately adopted, but the preferred numerical range is preferably 4,000 to 30,000, and more preferably 5,000 to 20,000. By adjusting to this weight-average molecular weight, a better anti-corrosion effect can be exerted.

[0095] When using a polymer (preferably a low molecular weight and / or (meth)acrylic acid-based polymer) in a water system, the use concentration (mg solid / L, hereinafter referred to as "mg / L") is not particularly limited, but it is preferably 3 to 30 mg / L, more preferably 5 to 20 mg / L, and further preferably 6 to 20 mg / L. The polymer is preferably added in such a way as to obtain such a concentration. In addition, in a preferred mode, when used in a water system, the use concentration of the (meth)acrylic acid-based polymer (more preferably the (meth)acrylic acid-based polymer containing a sulfonic acid group) is not particularly limited, but it is preferably 3 to 30 mg / L, more preferably 5 to 20 mg / L, and further preferably 6 to 20 mg / L. In addition, when used in a water system, the use concentration of the AA / AMPS polymer and / or the AA / HAPS polymer is not particularly limited, but it is preferably 3 to 30 mg / L, more preferably 5 to 20 mg / L, and further preferably 6 to 20 mg / L. In addition, as the use concentration of the polymer and the like, the preferred upper limit value and the preferred lower limit value in the "usage amount of the polymer (preferably a low molecular weight and / or (meth)acrylic acid-based polymer)" in the following section "1-4" can be appropriately adopted.

[0096] 1-4. Combined use of phosphorus compounds, film-forming amines and polymers, and preferred usage amounts and preferred ratios of each component, etc.

[0097] In the present embodiment, in the anti-corrosion method for a water system for suppressing the corrosion of metals in contact with the water system, by using the above-mentioned phosphorus compound, the above-mentioned film-forming amine, and the above-mentioned polymer, and by allowing these three components to be present in the water system, a better metal anti-corrosion effect can be achieved. Now, the more preferred usage amounts and usage ratios of the respective components in the water system, as well as the content ratios and compounding ratios in the chemical reagent, etc., will be described below.

[0098] In addition, in another aspect of the present embodiment, by using the film-forming amine and the polymer in combination in the water system, a technique for enhancing the metal anti-corrosion based on the phosphorus compound present in or used in the water system can be provided. Now, an explanation will be given regarding the better mass usage ratio or mass content ratio in the chemical reagent.

[0099] The operation time in the water system in the present embodiment is not particularly limited, but in order to better exert or maintain the anti-corrosion effect, the operation can be carried out for a long time. The preferred lower limit value is, for example, 0.5 months or more, preferably 1 month or more, more preferably 2 months or more, and further preferably 3 months or more. The preferred upper limit value is not particularly limited, but it is preferably 6 months or less, more preferably 5 months or less, and further preferably 4 months or less. The preferred numerical range is more preferably 2 to 4 months, during which the operation is preferably carried out in the following manner: allowing the film-forming amine and the polymer to be in contact with the metal material at least continuously or in a cyclic manner. In addition, the operation time can be the usage time.

[0100] <Preferred usage amounts of the phosphorus compound, the film-forming amine, and the polymer>

[0101] The "usage concentration (mg / L)" in the present embodiment can be the "usage amount (mg / L)" or the "addition amount (mg / L)", the "usage amount (mg / L)" can be the "usage concentration (mg / L)" or the "addition amount (mg / L)", and the "addition amount (mg / L)" can be the "usage concentration (mg / L)" or the "usage amount (mg / L)".

[0102] The amount of phosphorus compound (preferably phosphonic acid compound) used in the water system (mg PO4 / L, hereinafter referred to as "mg / L") is not particularly limited, but the lower limit value is preferably 0.1 mg / L or more, more preferably 0.5 mg / L or more, further preferably 1 mg / L or more, more preferably 2 mg / L or more, more preferably 3 mg / L or more. In addition, the upper limit value is not particularly limited, but from the viewpoint of the balance between reducing the amount of chemical reagent used and exerting the anti-corrosion effect, the usage amount is preferably 20 mg / L or less, more preferably 15 mg / L or less, further preferably 10 mg / L or less, more preferably 8 mg / L or less, more preferably 5 mg / L or less. The preferred numerical range is more preferably 0.1 to 10 mg / L, and further preferably 3 to 6 mg / L.

[0103] As a more preferred mode, for the amount of phosphonic acid compound used in the water system (mg PO4 / L), the lower limit value and the upper limit value of the amount of phosphoric acid compound used can be appropriately adopted. The more preferred numerical range is more preferably 0.1 to 10 mg / L, and further preferably 1 to 5 mg / L.

[0104] In addition, as a more preferred mode of the present embodiment, it is preferred to use phosphorus compounds continuously or discontinuously in the water system (preferably the cooling water system), and more preferably to add phosphorus compounds to the blowdown water.

[0105] The amount of film-forming amine (preferably aliphatic amine compound, more preferably aliphatic diamine compound) used in the water system (mg / L, hereinafter referred to as "mg / L") is not particularly limited, but the lower limit value is preferably 0.1 mg / L or more, more preferably 0.5 mg / L or more, further preferably 1 mg / L or more, more preferably 3 mg / L or more, more preferably 5 mg / L or more, more preferably 8 mg / L or more, and further preferably 10 mg / L or more. In addition, the upper limit value is not particularly limited, but from the viewpoint of the balance between reducing the amount of chemical reagent used and exerting the anti-corrosion effect, the usage amount is preferably 100 mg / L or less, more preferably 80 mg / L or less, further preferably 70 mg / L or less, more preferably 60 mg / L or less, more preferably 50 mg / L or less. The preferred numerical range is more preferably 5 to 70 mg / L, and further preferably 10 to 50 mg / L.

[0106] In addition, as a more preferred mode of the present embodiment, in order to synergistically exert the anti-corrosion effect of the film-forming amine by using the film-forming amine and the polymer in combination, it is preferred to use the film-forming amine continuously or discontinuously in the water system (preferably the cooling water system), and further preferably to add the film-forming amine continuously or discontinuously to the blowdown water, and more preferably to continuously add the film-forming amine to the blowdown water.

[0107] The amount of the polymer (preferably a low molecular weight and / or (meth)acrylic acid-based polymer) used in the water system (referred to as "mg / L" hereinafter in terms of mg solid / L) is not particularly limited, but the lower limit value is preferably 0.5 mg / L or more, more preferably 1 mg / L or more, further preferably 2 mg / L or more, more preferably 4 mg / L or more, more preferably 5 mg / L or more, more preferably greater than 5 mg / L, more preferably 6 mg / L or more, more preferably 8 mg / L or more, more preferably 10 mg / L or more, more preferably 13 mg / L or more, and more preferably 15 mg / L or more. In addition, the upper limit value is not particularly limited, but from the viewpoint of the balance between reducing the amount of chemical reagents used and exerting the anti-corrosion effect, the amount used is preferably 100 mg / L or less, more preferably 50 mg / L or less, further preferably 40 mg / L or less, more preferably 30 mg / L or less, and more preferably 20 mg / L or less. The preferred numerical range is more preferably 3 to 30 mg / L, further preferably 5 to 20 mg / L or 6 to 30 mg / L, and even more preferably 6 to 20 mg / L.

[0108] As a more preferred mode, for the amount of the low molecular weight and / or (meth)acrylic acid-based polymer used in the water system (mg solid / L), the preferred lower limit value and the preferred upper limit value of the amount of the polymer used can be appropriately adopted. The preferred numerical range is more preferably 3 to 30 mg / L, further preferably 5 to 20 mg / L or 6 to 30 mg / L, and even more preferably 6 to 20 mg / L.

[0109] As an even more preferred mode, for the amount of the (meth)acrylic acid-based polymer containing a sulfonic acid group used in the water system (mg solid / L), the preferred lower limit value and the preferred upper limit value of the amount of the polymer used can be appropriately adopted. The more preferred numerical range is more preferably 3 to 30 mg / L, further preferably 5 to 20 mg / L or 6 to 30 mg / L, and even more preferably 6 to 20 mg / L. In addition, as a more preferred mode, for the amount of the AA / AMPS polymer and / or AA / HAPS polymer used in the water system (mg solid / L), the preferred lower limit value and the preferred upper limit value of the amount of the polymer used can be appropriately adopted, and the more preferred numerical range is more preferably 3 to 30 mg / L, further preferably 5 to 20 mg / L or 6 to 30 mg / L, and even more preferably 6 to 20 mg / L.

[0110] In addition, as a more preferred mode of this embodiment, it is preferred to use the polymer continuously or discontinuously in the water system (preferably the cooling water system), and more preferably add it to the sewage.

[0111] <Preferred usage ratio or blending ratio of phosphorus compound, film-forming amine and polymer>

[0112] There is no particular limitation on the use ratio of the film-forming amine and the polymer in the water system or the compounding ratio in the chemical reagent, but it can be determined by appropriately combining the above-mentioned usage amounts (mg / L) of each of these components in the water system. The preferred range of the use ratio or compounding ratio is preferably 5 to 70:3 to 30 or 6 to 30, more preferably 10 to 50:5 to 20 or 6 to 20. Examples of such combinations include, but are not limited to, the combination of an aliphatic amine compound (such as an aliphatic diamine compound, etc.) and a low-molecular-weight monomer containing (meth)acrylic acid monomer and a sulfonic acid group (such as the above-mentioned AA / AMPS polymer or AA / HAPS polymer, etc.).

[0113] There is no particular limitation on the use ratio of the phosphorus compound and the film-forming amine in the water system or the compounding ratio in the chemical reagent, but it can be determined by appropriately combining the above-mentioned usage amounts (mg / L) of each of these components in the water system. The preferred range of the use ratio or compounding ratio is preferably 0.1 to 10 of the phosphorus compound:5 to 70 of the film-forming amine, more preferably 1 to 5 of the phosphorus compound:10 to 50 of the film-forming amine. Examples of such combinations include, but are not limited to, the combination of a phosphonic acid compound and an aliphatic amine compound (such as an aliphatic diamine compound, etc.).

[0114] There is no particular limitation on the use ratio of the phosphorus compound and the polymer in the water system or the compounding ratio in the chemical reagent, but it can be determined by appropriately combining the above-mentioned usage amounts (mg / L) of each of these components in the water system. The preferred range of the use ratio or compounding ratio is preferably 0.1 to 10 of the phosphorus compound:3 to 30 or 6 to 30 of the polymer, more preferably 1 to 5 of the phosphorus compound:5 or 6 to 20 of the polymer. Preferred examples of such combinations include, but are not limited to, the combination of a phosphonic acid compound and a low-molecular-weight monomer containing (meth)acrylic acid monomer and a sulfonic acid group (such as the above-mentioned AA / AMPS polymer or AA / HAPS polymer, etc.).

[0115] There is no particular limitation on the use ratio of the phosphorus compound, the film-forming amine and the polymer in the water system or the compounding ratio in the chemical reagent, but it can be determined by appropriately combining the above-mentioned usage amounts (mg / L) of each of these components in the water system. The preferred range of the use ratio or compounding ratio is preferably 0.1 to 10 of the phosphorus compound:5 to 70 of the film-forming amine:3 to 30 or 6 to 30 of the polymer, more preferably 1 to 5 of the phosphorus compound:10 to 50 of the film-forming amine:5 or 6 to 20 of the polymer. Preferred examples of such combinations include, but are not limited to, the combination of a phosphonic acid compound, an aliphatic amine compound (such as an aliphatic diamine compound, etc.) and a low-molecular-weight monomer containing (meth)acrylic acid monomer and a sulfonic acid group (such as the above-mentioned AA / AMPS polymer or AA / HAPS polymer, etc.).

[0116] <Optional component>

[0117] In the present embodiment, in addition to the above components (specifically, film-forming amines, polymers, and phosphorus compounds), optional components can be appropriately used in the water system or can be included in the chemical reagent within the scope of not impairing the effects of the present invention. These optional components are not particularly limited. For example, one or more selected from the group consisting of pH regulators, antifoaming agents, corrosion inhibitors other than the above components, scale inhibitors, fungicides, and algaecides can be used.

[0118] In the present embodiment, in addition to the combination of the above film-forming amines and polymers or the combination of these components and phosphorus compounds, it is preferably further provided with a scale inhibitor, which exists in the water system as a component other than these. Examples of the scale inhibitor include maleic acid-based polymers and their salts, polyaspartic acid and its salts, and one or more selected from these can be used.

[0119] In addition, in the present embodiment, in addition to the combination of the above film-forming amines and polymers or the combination of these components and phosphorus compounds, it is preferably further provided with a slime control agent, which exists in the water system as a component other than these. Examples of the slime control agent are not particularly limited, but hypochlorous acid and its salts, chlorine, hypobromous acid and its salts, stabilized chlorine, stabilized bromine, and organic fungicides, etc. can be used, and one or more selected from these can be used.

[0120] In the present embodiment, in addition to the combination of the above film-forming amines and polymers or the combination of these components and phosphorus compounds, it is preferable that a corrosion inhibitor other than these components (more preferably a metal compound for anticorrosion) exists in the water system. The metal compound for anticorrosion is a metal compound used for anticorrosion, and the metal compound is a metal compound that can easily release heavy metal ions into the water. As long as the metal compound can exert this effect, the metal compound is not particularly limited.

[0121] Examples of the "corrosion inhibitor other than these components" include, but are not particularly limited to, metal compounds for anticorrosion such as zinc salts, tin salts, manganates, aluminum, and aluminates; organic acid compounds, polyaspartic acid and its salts, polyitaconic acid and its salts, and amino acid compounds, etc. One or more selected from the group consisting of these can be used. Among them, metal compounds for anticorrosion are more preferred, and among these metal compounds for anticorrosion, zinc salts and / or tin salts are preferred, and zinc salts are more preferred. When a phosphoric acid compound is selected for the "phosphorus compound", it is desirable to exclude the phosphoric acid compound from the "corrosion inhibitor other than these components", and when a phosphonic acid compound is selected, the phosphoric acid compound can be selected from the "corrosion inhibitor other than these components".

[0122] As a preferable "corrosion inhibitor other than these components" that can be used in combination further, one or more selected from the group consisting of phosphoric acid compounds (orthophosphoric acid, PBTC, hexanemetaphosphoric, etc.), zinc salts (zinc chloride, zinc sulfate, etc.), and corrosion inhibitors for copper (benzotriazole / tolyltriazole, etc.) that are typically used in cooling water systems can be used.

[0123] The usage amount (mg solid / L, hereinafter referred to as "mg / L") of the "corrosion inhibitor other than these components" is not particularly limited, but the preferable lower limit is preferably 0.1 mg / L or more, more preferably 0.5 mg / L or more. The preferable upper limit is preferably 5 mg / L or less, more preferably 4 mg / L or less, further preferably 3 mg / L or less, and more preferably 2 mg / L or less. By making the component (C) corrosion inhibitor present in the water system in a preferable amount, a corrosion prevention effect equal to or higher than the combined effect of the component (A) copolymer and the component (B) maleic acid-based polymer can be obtained better. As a result, when obtaining a corrosion prevention effect equal to or higher than that of the components (A) and (B), adding the component (C) can reduce the addition amounts of the components (A) and (B) more.

[0124] 1-5. Metal anti-corrosion method for water systems

[0125] As described above, in the method for metal anticorrosion treatment of a water system according to the present embodiment, a film-forming amine, a polymer, and a phosphorus compound can be used in combination, and preferably these three components are present in the water system simultaneously. In addition, in the present embodiment, each of these components can be added to the water system continuously or intermittently. In the present embodiment, each of these components can be added to the water system simultaneously or at separate times. The water system can include one or more chemical injection devices for adding chemical reagents to the water system. Each chemical injection device can inject a single component, a mixture of two components, and other components or a mixture of three components into the water system simultaneously or at different times, so that these three components are present in the water system simultaneously. As a preferred example of this embodiment, it is preferred that the film-forming amine is present in the water system as an online scale inhibitor and adjusted in such a way that these three components are present in the water system simultaneously. In addition, as an example of the location for mixing these components, the present embodiment mentions the inside of the flow path (e.g., the circulating water path) or piping of the water system, or tanks (e.g., pits, etc.) such as chemical reagent storage tanks or chemical reagent mixing tanks that can be included in the water system, but the present embodiment is not limited to these locations. In addition, the water system can be appropriately equipped with measuring devices capable of measuring the concentration of each chemical reagent (the concentration of each component) in the water system and measuring devices capable of measuring the water quality of the water system, etc. In the present embodiment, these measurement results can be transmitted to a control unit, etc., and the control unit, etc. can control or manage the method of the present embodiment or its steps or operations.

[0126] As described above, in the method for metal anticorrosion of a water system according to the present embodiment, it is preferred that a combination of a film-forming amine and a polymer or a combination of a film-forming amine, a polymer, and a phosphorus compound is present in the water system in a predetermined mass use ratio or mass content ratio.

[0127] In the present embodiment, a combination of a film-forming amine and a polymer or a combination of a film-forming amine, a polymer, and a phosphorus compound can be added to the water system as a single-component chemical reagent or as a multi-component chemical reagent (e.g., a combined product).

[0128] As another aspect of the present embodiment, an anticorrosion method for a water system can be provided by adding a water treatment agent containing at least one of a phosphorus compound, a film-forming amine, and a polymer to the water system, so that the phosphorus compound, the film-forming amine, and the polymer are present in the water system.

[0129] In addition, as the combined use of a film-forming amine and a polymer in the water system, or the combined use of a film-forming amine, a polymer, and a phosphorus compound in the water system, these three components can be added simultaneously or at different times so that these three components are present in the water system. The addition of these three components can be carried out continuously or intermittently.

[0130] In the present embodiment, as a more preferred mode, the following can be used to provide a method for metal anti-corrosion treatment for a water system: (i) a metal anti-corrosion treatment agent, (ii) a water treatment agent, or (iii) a water treatment agent for metal anti-corrosion or a combined product of water treatment agents. In the present specification, the combined product can be a product group or a kit product.

[0131] (i) A metal corrosion inhibitor containing a phosphorus compound, a film-forming amine, and a polymer.

[0132] (ii) A water treatment agent containing a film-forming amine and / or a polymer,

[0133] wherein, when used in a water system, the water treatment agent is used by combining a film-forming amine and a polymer to enhance metal anti-corrosion based on the phosphorus compound.

[0134] (iii) A water treatment agent for metal anti-corrosion containing at least one of a phosphorus compound, a film-forming amine, and a polymer,

[0135] wherein, when used for metal anti-corrosion in a water system, the water treatment agent is used by combining a phosphorus compound, a film-forming amine, and a polymer in the water system. The water treatment agent can be a combined product of water treatment agents composed of at least one, two, or three selected from the group consisting of: a first water treatment agent containing a phosphorus compound, a second water treatment agent containing a film-forming amine, and a third water treatment agent containing a polymer.

[0136] As a more preferred aspect of the present embodiment, when used in a water system, reagents such as the above-mentioned metal corrosion inhibitor, water treatment agent, and third water treatment agent preferably contain or are configured such that the addition amount of the polymer (preferably a copolymer of a (meth)acrylic acid monomer and a sulfonic acid group-containing monomer) is 6 mg / L or more.

[0137] The water system to which the present embodiment is applied is not particularly limited, and examples include a cooling water system, an RO water system, a pulp and paper water system, and a scrubber water system, etc. In the present embodiment, as long as the water quality is the water quality of a general water system (preferably a cooling water system), a sufficient anti-corrosion effect is exerted.

[0138] Regarding the water quality conditions of the water system, the acid consumption (pH 8.3) is not particularly limited. From the viewpoint of better anti-corrosion effect, the upper limit value is preferably 1000 mg CaCO3 / L or less, more preferably 500 mg CaCO3 / L or less, further preferably 300 mg CaCO3 / L or less. The lower limit value is preferably 10 mg CaCO3 / L or more, more preferably 25 mg CaCO3 / L or more, more preferably 50 mg CaCO3 / L or more, more preferably 50, 75 or 100 mg CaCO3 / L or more. The preferred numerical range is more preferably 25 to 500 mg CaCO3 / L, and further preferably 100 to 300 mg CaCO3 / L. The acid consumption (pH 8.3) can be determined according to the industrial water test method of JIS K0101. The acid consumption is expressed by converting the amount of alkaline components (such as bicarbonate, carbonate and hydroxide) contained in water into the equivalent concentration of calcium carbonate (unit: mg CaCO3 / L).

[0139] Regarding the water quality conditions of the water system, the calcium hardness is not particularly limited. From the viewpoint of better anti-corrosion effect, although the upper limit value is not particularly limited, for example, it is 1000 mg CaCO3 / L or less, more preferably 500 mg CaCO3 / L or less, more preferably 300 mg CaCO3 / L or less. The lower limit value is preferably 5 mg CaCO3 / L or more, further preferably 10 mg CaCO3 / L or more, more preferably 25 mg CaCO3 / L or more, more preferably 50, 75 or 100 mg CaCO3 / L or more. The preferred numerical range is preferably 25 to 300 mg CaCO3 / L. The calcium hardness can be determined according to the industrial water test method of JIS K0101.

[0140] Regarding the water quality conditions of the water system, the pH of the water system is not particularly limited. However, from the viewpoint of better anti-corrosion effect, it is preferably 6 to 11, more preferably 6.5 to 10, and further preferably 7 to 9. In addition, the water temperature of the water system is not particularly limited. However, from the viewpoint of better anti-corrosion effect, it is preferably 0 to 100 °C, more preferably 5 to 80 °C, and further preferably 10 to 60 °C.

[0141] As a preferred mode of this embodiment, it is preferably applied to a water system in which metal materials that are easily corroded by water are used at various positions (such as heat exchangers and pipes, etc.), more preferably applied to a cooling water system, and further preferably applied to a circulating cooling water system. According to this embodiment, the anti-corrosion effect of the anti-corrosion treatment method of the present invention is fully exerted through more preferred application.

[0142] The method of this embodiment can also be implemented by a control unit including a CPU, etc. in a device (such as a computer, PLC, server, and cloud service, etc.) for managing the above-mentioned metal anti-corrosion treatment or the following cooling water system. In addition, the method of this embodiment can also be stored as a program in a hardware resource including a recording medium (non-volatile memory (such as a USB memory), SSD, HDD, CD, DVD, Blu-ray Disc, etc.), and implemented by the control unit. The recording medium is preferably a computer-readable recording medium. A device including a control unit or a system such as a metal anti-corrosion treatment system can also be provided, in which the control unit controls the addition of chemical reagents to the water system. In addition, as a component of the computer, the management device at least has a CPU, and may also include an input unit such as a keyboard, a communication unit such as a network, a display unit such as a monitor, a storage unit such as an HDD, ROM, and RAM, etc., and one or more than two of these can be selected. Among them, a RAM, a storage unit, a display unit, and an input unit are preferably included. Each selected component is connected, for example, through a bus as a data transmission path.

[0143] <Cooling water system>

[0144] The cooling water system applied to this embodiment is not particularly limited, but is preferably a system in which cooling water is used for the operation of air-conditioning equipment in buildings and regional facilities, etc. or heat exchangers in manufacturing plants, etc. The cooling water system can be a transient mode type, an open-circulation type, or a closed-circulation type.

[0145] In this embodiment, when applied to a circulating cooling water system, an excellent anti-corrosion effect can be exerted in the circulating cooling water system.

[0146] The circulating cooling water system is not particularly limited, but is preferably, for example, a water system including a cooling tower installed in air-conditioning equipment, petrochemical refineries, and conventional factories, etc. The circulating cooling water system is preferably configured to indirectly cool heat sources that generate heat in such air-conditioning machines and general factories, etc., and the circulating cooling water system can be a conventional water system configured to include a heat exchanger, a circulating water path, and a cooling tower.

[0147] The type of the circulating cooling water system is not particularly limited, but the system can be an open-circulation cooling water system or a closed-circulation cooling water system. As an open-circulation cooling water system, a configuration that allows the cooling water to circulate in an open manner is preferred. As a closed-circulation cooling water system, a configuration that allows the cooling water to circulate in a closed manner is preferred.

[0148] In addition, the metal anti-corrosion treatment method for a cooling water system according to the present embodiment (more specifically, the metal anti-corrosion treatment method for metal components in a cooling water system) preferably includes at least the following steps: adding each of a film-forming amine, a polymer, and a phosphorus compound to the cooling water system, and bringing these components into contact with the metal components. At this time, the film-forming amine and the polymer or the film-forming amine, the polymer, and the phosphorus compound may be added as a metal anti-corrosion treatment agent of a single-component chemical reagent, or added as a combined product of a metal anti-corrosion treatment agent of a multi-component chemical reagent. The film-forming amine, the polymer, and the phosphorus compound may be added to the cooling water system simultaneously or at different times, and are preferably added in such a manner that these three components coexist in the water system. There is no particular limitation on the time when these three components coexist in the water system, and it may be continuous or intermittent. For example, the phosphorus compound, the polymer (first polymer), and the film-forming amine may be added to the cooling water system in sequence. In addition, after mixing these, a polymer (second polymer) may be further added. The first polymer and the second polymer may be the same or different polymers. The usage amount of the second polymer is preferably 0.5 to 2 times or more, more preferably about 1.5 to 2.5 times, the usage amount of the first polymer. When the first polymer and the second polymer are the same polymer, the total usage amount of the first polymer and the second polymer may be the total amount used or added.

[0149] In addition, the position where the chemical reagent is added is not particularly limited, and may be any position in the cooling water system. Examples include a blowing means, a water spraying means, a pit, a makeup water supply means, a chemical reagent injection means, a circulating water path, a transfer pump, and a heat exchanger, etc. Preferably, the position is a makeup water supply means, a chemical reagent injection means, a circulating water path, or a transfer pump, etc., and the addition may be performed at one or more positions selected from these. By adding these three components in such a manner that they exist at any position in the water system, a better anti-corrosion effect on the metal materials in contact with water downstream thereof can be obtained. In addition, when all or part of the water system circulates, as a result of the circulation of the water system, these three components are mixed, whereby a better anti-corrosion effect on the metal materials in contact with water in the water system can be obtained.

[0150] As described above, the metal anti-corrosion treatment method according to the present embodiment can impart an excellent anti-corrosion effect to the metal components in contact with water.

[0151] Reference will be made to Figure 1 describe the metal anti-corrosion treatment method for the open-circuit cooling water system 1 as an example of the present embodiment, but the present embodiment is not limited thereto.

[0152] In the open recirculating cooling water system 1, water containing a film-forming amine, a polymer, and a phosphorus compound is transported from the sump 15 through the circulation water path 20 to the heat exchanger 30 by the transfer pump 21, then passes through the heat exchanger 30 and returns to the open cooling tower 10 through the circulation water path 20. In the cooling tower 10, the water containing these components passes through the spraying means 12 and the packing area 13, is stored in the sump 15, and is again transported to the circulation water path 20 by the pump 21. In the case of this embodiment, the anticorrosion effect can be maintained in the cooling water system during this circulation. As a result of this circulation, the film-forming amine and the polymer or the film-forming amine, the polymer, and the phosphorus compound present in the water in the water system can come into contact with the metal members, and the anticorrosion effect on the metal members can be exerted. It is preferable to use a chemical injection device to add the film-forming amine, the polymer, and the phosphorus compound to the water system, and the chemical injection device can add each component or a mixture of two or three of these components so that the three components are present in the water system together. In addition, the addition amounts of the respective components can be adjusted so that each component is within a corresponding predetermined concentration range in the water system.

[0153] The film-forming amine and the polymer or the film-forming amine, the polymer, and the phosphorus compound are transported to the sump 15 simultaneously or at different times by one or more chemical reagent injection means 17. These components can be mixed in the piping during transportation, or can be mixed in the sump 15. In addition, one or more chemical reagent injection means 17 can be provided. For example, a plurality of individual chemical reagent injection means can be provided respectively for each of the film-forming amine, the polymer, and the phosphorus compound, or one chemical reagent injection means can be provided for adding a single-component chemical reagent containing these to the water system or for mixing these components. The makeup water supply means 16 supplies water to the sump 15 as needed to compensate for any water shortage caused by evaporation or the like, and the flow path for supplying the makeup water to the sump 15 can be configured so that one or more chemical reagents from the chemical reagent injection means 17 can be added. The cooling air passes through 13 and 12 from the louver 18, and the external air discharged by the blowing means 11 is discharged from 11.

[0154] In the description of examples of the method for metal anticorrosion treatment of the water system according to this embodiment, etc., the following descriptions that are the same as or overlap with the following details (such as "2." to "3." etc.) have been appropriately omitted: various technical features, various structures, various definitions, various terms, various treatment methods, and various means of phosphorus compounds, film-forming amines, polymers, their use concentrations and use ratios, metal anticorrosion treatment of the water system, metal anticorrosion treatment management in the water system, metal anticorrosion system for the water system, and metal anticorrosion treatment method for the water system, etc. However, the descriptions in "1." to "3." etc. can be applied to any embodiment, and can be appropriately adopted in each embodiment.

[0155] 2. Metal corrosion inhibitors, etc. according to this embodiment

[0156] In the description of examples of metal corrosion inhibitors, water treatment agents, and combined products for water treatment agents, etc. according to the present invention, the following descriptions that are the same as or overlap with the above details (e.g., "1.") and the following details (e.g., "3.", etc.) have been appropriately omitted: various technical features, various structures, various definitions, various terms, various treatment methods, and various means, etc. of phosphorus compounds, film-forming amines, polymers, their use concentrations and use ratios, metal anti-corrosion treatment for water systems, management of metal anti-corrosion treatment in water systems, metal anti-corrosion systems for water systems, and metal anti-corrosion treatment methods for water systems, etc. However, the descriptions in "1." to "3.", etc. can be applied to any embodiment, and can be appropriately adopted in each embodiment.

[0157] By using phosphorus compounds, film-forming amines, and polymers in a water system, an extremely excellent anti-corrosion effect can be exerted. That is, the combination of phosphorus compounds, film-forming amines, and polymers can be included as an active substance of, for example, a metal corrosion inhibitor, a water treatment agent, or a chemical reagent for a water system in an anti-corrosion composition in the water system, or used for such a composition, etc. In this embodiment, the composition can be a reagent, and the reagent can be a composition. Preferred are compositions or reagents in which the component structures of the phosphorus compounds, film-forming amines, and polymers used in this embodiment are such that the addition amounts to the water system are each not less than a predetermined amount, or alternatively, it is preferred to use a composition or reagent such that the addition amount to the water system is not less than a predetermined amount.

[0158] In addition, phosphorus compounds, film-forming amines, polymers, or mixtures thereof can be used to manufacture the metal corrosion inhibitor for the water system of this embodiment.

[0159] This embodiment can also provide phosphorus compounds, film-forming amines, and polymers or mixtures or uses thereof for metal anti-corrosion, etc. in a water system. In addition, this embodiment can also provide phosphorus compounds, film-forming amines, polymers, or mixtures thereof for metal anti-corrosion, etc. in a water system.

[0160] This embodiment can also provide a metal anti-corrosion method for a water system and a metal anti-corrosion treatment method for a water system, which use phosphorus compounds, film-forming amines, polymers, or mixtures thereof, or a metal corrosion inhibitor for a water system, a water treatment agent, and a combined product for a water treatment agent, etc.

[0161] In addition, as another aspect of this embodiment, a metal corrosion inhibitor containing phosphorus compounds, film-forming amines, and polymers can be provided.

[0162] In addition, as another aspect of the present embodiment, there can be provided a phosphorus compound, a film-forming amine, and a polymer for metal anti-corrosion or as a metal corrosion inhibitor, or their uses, or a composition containing these three components, or the use of such a composition.

[0163] In addition, as another aspect of the present embodiment, there can be provided a phosphorus compound, a film-forming amine, and a polymer for manufacturing a metal corrosion inhibitor or used in the manufacture of a metal corrosion inhibitor, or their uses, or a composition including these three components, or the use of such a composition.

[0164] As another aspect of the present embodiment, there can be provided a water treatment agent for metal anti-corrosion containing at least one of a phosphorus compound, a film-forming amine, and a polymer. When used for metal anti-corrosion in a water system, the water treatment agent is used by combining a phosphorus compound, a film-forming amine, and a polymer in the water system. The water treatment agent can be a combined product for water treatment agents composed of at least one, two, or three selected from the group consisting of a first water treatment agent containing a phosphorus compound, a second water treatment agent containing a film-forming amine, and a third water treatment agent containing a polymer.

[0165] As another aspect of the present embodiment, there is provided a water treatment agent containing a film-forming amine and / or a polymer. When used in a water system, the water treatment agent is used by combining a film-forming amine and a polymer to enhance metal anti-corrosion based on a phosphorus compound.

[0166] In addition, as another aspect of the present embodiment, there can be provided a phosphorus compound, a film-forming amine, and a polymer for manufacturing a reagent, used in the manufacture of a reagent, or the use of a reagent, or the uses of these.

[0167] In addition, as another aspect of the present embodiment, there can be provided an anti-corrosion method for a water system including using the above reagent to inhibit the corrosion of metal in contact with water.

[0168] The polymer is preferably a low molecular weight polymer, more preferably a low molecular weight with a weight average molecular weight of 500 to 100,000. The polymer is preferably a water-soluble organic polymer, more preferably a copolymer, more preferably a copolymer of a (meth)acrylic acid monomer and a sulfonic acid group-containing monomer, and further preferably a copolymer of (a) a (meth)acrylic acid monomer and (b) a monomer containing (i) an amide group and a sulfonic acid group or (ii) a hydroxyl group and a sulfonic acid group. A composition containing the polymer is preferably included in an amount of 6 mg / L or more added to the water system, or a polymer with an addition amount of 6 mg / L or more to the water system is preferably used.

[0169] The polymer is preferably a (meth)acrylic polymer containing a sulfonic acid group, and the molar ratio between the (meth)acrylic monomer and the sulfonic acid monomer in the polymer is preferably 60 to 95:40 to 5. Among the (meth)acrylic polymers, AA / AMPS polymer and / or AA / HAPS polymer are preferred.

[0170] The phosphorus compound is preferably a phosphonic acid compound. The film-forming amine is preferably a long-chain aliphatic amine compound, and among them, a long-chain aliphatic diamine compound is preferred.

[0171] The usage ratio between the film-forming amine and the polymer in the water system or the blending ratio in the chemical reagent is preferably 5 to 70:3 to 30.

[0172] In addition, the usage ratio between the phosphorus compound and the film-forming amine in the water system or the blending ratio in the chemical reagent is preferably 0.1 to 10 of the phosphorus compound:5 to 70 of the film-forming amine.

[0173] In addition, the usage ratio between the phosphorus compound and the polymer in the water system or the blending ratio in the chemical reagent is preferably 0.1 to 10 of the phosphorus compound:3 to 30 or 6 to 30 of the polymer.

[0174] The usage ratio between the phosphorus compound, the film-forming amine and the polymer or the blending ratio in the chemical reagent is preferably 0.1 to 10 of the phosphorus compound:5 to 70 of the film-forming amine:3 to 30 or 6 to 30 of the polymer.

[0175] 3. The technology of the present invention can also adopt the following technical features, structures and other aspects.

[0176] <1> An anti-corrosion method for a water system, which is used to inhibit the corrosion of metals in contact with the water system. The method includes using a phosphorus compound, a film-forming amine, and a copolymer of a (meth)acrylic monomer and a monomer containing a sulfonic acid group in the water system. The weight-average molecular weight of the copolymer is preferably 500 to 100,000. The monomer ratio between the (meth)acrylic monomer and the monomer containing a sulfonic acid group in the copolymer is preferably 60 to 95:40 to 5. Preferably, the usage amount of the copolymer of the (meth)acrylic monomer and the monomer containing a sulfonic acid group is greater than 5 mg / L.

[0177] <2> According to the method described in <1> above, wherein the copolymer is a copolymer obtained from (a) a (meth)acrylic monomer and (b) (i) a monomer containing an amide group and a sulfonic acid group and / or (ii) a monomer containing a hydroxyl group and a sulfonic acid group. The monomer ratio between the (meth)acrylic monomer and the monomer containing an amide group and a sulfonic acid group in the copolymer is preferably 60 to 95:40 to 5.

[0178] <3>The method according to <1> or <2> above, wherein the film-forming amine is an aliphatic amine compound. The aliphatic amine compound is preferably a long-chain aliphatic amine compound. The aliphatic amine compound is preferably an aliphatic monoamine compound and / or an aliphatic diamine compound, more preferably an aliphatic diamine compound.

[0179] <4>The method according to any one of <1> to <3> above, wherein the phosphorus compound is a phosphoric acid compound and / or a phosphonic acid compound, more preferably a phosphonic acid compound. A mixture further comprising a corrosion inhibitor other than the phosphorus compound (e.g., a zinc salt and / or a copper corrosion inhibitor) can also be used for the phosphorus compound.

[0180] <5>The method according to any one of <1> to <4> above, wherein when using the film-forming amine, a copolymer of (meth)acrylic acid monomer and a sulfonic acid group-containing monomer is used in combination in the water system.

[0181] <6>The method according to any one of <1> to <5> above, wherein the water system is a cooling water system. The cooling water system is preferably an open-circulation type or a closed-circulation type, and more preferably an open-circulation type cooling water system.

[0182] <7>A metal corrosion inhibitor comprising a phosphorus compound, a film-forming amine, and a polymer. The polymer is preferably a low-molecular-weight polymer, more preferably a low-molecular-weight polymer having a weight-average molecular weight of 500 to 100,000. Further, the polymer is preferably a water-soluble organic polymer, more preferably a copolymer of (meth)acrylic acid monomer and a sulfonic acid group-containing monomer. The copolymer according to any one of <1> to <6> above is preferably used as the polymer. The phosphorus compound and / or the film-forming amine is preferably the compound according to <3> and / or <4> above. The metal corrosion inhibitor is preferably configured such that the polymer can be used at an addition amount greater than 5 mg / L, or preferably the metal corrosion inhibitor is used in such a manner that the addition amount of the polymer is greater than 5 mg / L.

[0183] <8>The use of a phosphorus compound, a film-forming amine, and a polymer for metal anti-corrosion or as a metal corrosion inhibitor, or their use, or a composition comprising these three components, or the use of such a composition. The polymer is preferably the polymer according to <7> above or the copolymer according to any one of <1> to <6> above. The phosphorus compound and / or the film-forming amine is preferably the compound according to <3> and / or <4> above. The polymer is preferably used at greater than 5 mg / L in the water system, or the composition is preferably configured such that the composition can be used at an addition amount of the polymer greater than 5 mg / L.

[0184] <9>Use of a phosphorus compound, a film-forming amine, and a polymer for manufacturing a metal corrosion inhibitor or the like, or their use in manufacturing a metal corrosion inhibitor or the like, or one, two, or three of these, or a composition containing these three components, or the use of such a composition. The polymer is preferably the polymer according to <7> above or the copolymer according to any one of <1> to <6> above. The phosphorus compound and / or the film-forming amine are preferably the compounds according to <3> and / or <4> above. The polymer is preferably used in a water system at a concentration greater than 5 mg / L, or the composition is preferably configured such that the composition can be used with an addition amount of the polymer greater than 5 mg / L.

[0185] <10>A water treatment agent for metal anti-corrosion, which contains at least one of a phosphorus compound, a film-forming amine, and a polymer. When used for metal anti-corrosion in a water system, the water treatment agent is used by combining the phosphorus compound, the film-forming amine, and the polymer in the water system. The water treatment agent can be a combined product of water treatment agents composed of at least one, two, or three selected from the group consisting of a first water treatment agent containing a phosphorus compound, a second water treatment agent containing a film-forming amine, and a third water treatment agent containing a polymer. The polymer is preferably the polymer according to <7> above or the copolymer according to any one of <1> to <6> above. The phosphorus compound and / or the film-forming amine are preferably the compounds according to <3> and / or <4> above. The polymer is preferably used in a water system at a concentration greater than 5 mg / L, or the water treatment agent is preferably configured such that the water treatment agent can be used with an addition amount of the polymer greater than 5 mg / L.

[0186] <11>A water treatment agent containing a film-forming amine and / or a polymer, wherein

[0187] When used in a water system, the water treatment agent is used by combining the film-forming amine and the polymer to enhance metal anti-corrosion based on a phosphorus compound. The polymer is preferably the polymer according to <7> above or the copolymer according to any one of <1> to <6> above. The phosphorus compound and / or the film-forming amine are preferably the compounds according to <3> and / or <4> above.

[0188] <12>Use of a phosphorus compound, a film-forming amine, and a polymer for manufacturing the reagent according to any one of [7] to

[11] above, their use in manufacturing the reagent according to any one of [7] to

[11] above, or for the reagent according to any one of [7] to

[11] above.

[0189] <13>An anti-corrosion method for a water system for inhibiting the corrosion of metals in contact with water, a method for enhancing the anti-corrosion of metals based on phosphorus compounds, or a method for reducing the amount of phosphorus used in a water system, which comprises using the components or reagents described in <7> to <12> above.

[0190] <Example>

[0191] Embodiments of the present invention will now be described with reference to the following examples and comparative examples, etc. However, it should be noted that the following examples are only examples of representative embodiments of the present invention, and the scope of the present invention should not be narrowly construed as being only these examples.

[0192] <Test Example 1>

[0193] <Experimental Conditions>

[0194] Pure water was filled in a 1L glass beaker, and sodium bicarbonate solution and calcium chloride solution were added to adjust the pH to 8.4, the acid consumption to 150 mg CaCO3 / L, and the calcium hardness to 150 mg CaCO3 / L.

[0195] 4 mg PO4 / L of HEDP (1-hydroxyethylidene-1,1-diphosphonic acid) was added as a corrosion inhibitor and 5 mg solid / L of AA / AMPS polymer (monomer ratio (mol% ratio) 80:20, weight average molecular weight 20,000) was added as a scale inhibitor. 50 mg / L of a film-forming amine (alkyl propanediamine (alkyl group having 16 to 18 carbon atoms)) was added, and then 10 mg solid / L of various polymers was added.

[0196] Tables 1 to 3 show Test Example 1 (Reference Examples 1-1 to 1-6 and Examples 1-7 to 1-10), Test Example 2 (Reference Example 2-1 and Examples 2-2 to 2-4), and Test Example 3 (Reference Examples 3-1 to 3-3 and Examples 3-4 to 3-5) for each combination of phosphorus compounds, film-forming amines, and polymer components.

[0197] For the reference examples, experiments were also conducted without adding HEDP and without adding the film-forming amine.

[0198] As shown in Tables 1 and 2, the polymers used were AA / AMPS polymers, AA / HAPS polymers, and polymaleic acid-based polymers, which had a weight average molecular weight of 400 to 110,000. The molecular weight of the polymer is the weight average molecular weight, which is a value determined by GPC analysis (standard substance PAANA, sodium polyacrylate, manufactured by PSS).

[0199] <Corrosion Rate Test (mg / dm 2 / day)>

[0200] The test piece 101, which is a test piece of SPCC (15mm’30mm), is immersed in the test water 102, and a rotary corrosion test device 100 equipped with a temperature control device 104 and a stirring device 103 ( Figure 2 ) is used to conduct a 3-day test at a water temperature of 40 °C at 150 rpm. The temperature control device 104 heats and cools the test water 102, and the stirring device 103 stirs the test water with a stirrer. The material of SPCC (steel plate cold commercial: a kind of cold-rolled carbon steel plate) is low-carbon steel with a carbon content of less than 0.15%.

[0201] After the test is completed, the test piece is pulled out, the corrosion is removed with hydrochloric acid, and the corrosion weight is measured. The corrosion rate (mg / dm 2 / day) is calculated based on the corrosion weight.

[0202] In addition, in order to verify the effects of different corrosion inhibitors used, PBTC (4mg PO4 / L) is also used instead of HEDP (4mg PO4 / L) for evaluation.

[0203] [Table 1]

[0204] Table 1 Measurement results of corrosion rate according to polymer addition

[0205]

[0206] [Table 2]

[0207] Table 2 Influence of polymer molecular weight

[0208]

[0209] [Table 3]

[0210] Table 3 Influence of phosphoric acid type

[0211]

[0212] <Results / Discussion>

[0213] Tables 1 and 2 show the results of using HEDP as a corrosion inhibitor, and Table 3 shows the results of using PBTC. It was confirmed that regardless of the type of corrosion inhibitor, the use of AA / AMPS or AA / HAPS with a molecular weight of 4,000 to 20,000 significantly improved the anti-corrosion effect and led to an extended lifespan of the metal during the addition of the film-forming amine. In addition, from the trend of the corrosion rate, it is considered that the AA / AMPS ratio and AA / HAPS ratio (mol%) of the AA / AMPS polymer and AA / HAPS polymer are preferably 1 to 95:99 to 5, more preferably 60 to 95:40 to 5, and further preferably 75 to 90:25 to 10. As a result, it was confirmed that the anti-corrosion effect on the metal material in contact with water was significantly improved by the presence of three components: a film-forming amine, a low-molecular-weight (meth)acrylic acid-based polymer containing a sulfur atom, and a phosphonic acid compound in the water system. In addition, it was confirmed that by using the film-forming amine and the low-molecular-weight (meth)acrylic acid-based polymer containing a sulfur atom in combination, there was a synergistic effect on the corrosion inhibition effect on the metal material in contact with water. In addition, it is preferred that the polymer is used in an amount greater than 5 mg / L in the water system.

[0214] In this specification, for convenience, numbers such as "first, second, third...", letters in the alphabet such as "A, B, C...", and "primary, secondary, tertiary..." are added in the description. However, the present invention should not be narrowly construed by using these, such as in the sequence order, etc., and the sequence order can be freely changed. The combined product can be for combined use. In addition, in this specification, for example, the "do(ing) (present form)" in "managing" can be used for methods, processes, means, or steps, etc. These terms can be appropriately replaced. For example, "step" can be replaced with method, process, or means, etc. in the relevant form of the verb, "process" can be replaced with method, step, or means, etc. in the relevant form of the verb, and "means" can be replaced with method, process, or step, etc. in the relevant form of the verb. In addition, in this specification, "system" can be an institution, device, means, or unit, "institution" can be a system, device, means, or unit, "device" can be a system, institution, means, or unit, "means" can be an institution, system, device, or unit, "unit" can be an institution, means, device, or system, or the institution, means, or device included therein.

[0215] [Description of Reference Numerals]

[0216] 1 Open recirculating cooling water system

[0217] 10 Open cooling tower

[0218] 11 Blowing means

[0219] 12 Spraying means

[0220] 13 Filler area

[0221] 14 Space

[0222] 15 Pit

[0223] 16 Makeup water supply means

[0224] 17 Chemical reagent injection means

[0225] 18 Air window

[0226] 20 Circulating water path

[0227] 21 Transfer pump

[0228] 30 Heat exchanger

Claims

1. An anti-corrosion method for a water system, which is used to inhibit the corrosion of metals in contact with the water system, and the method includes: In the water system, use a phosphorus compound, a film-forming amine, and a copolymer of (meth)acrylic acid monomers and sulfonic acid group-containing monomers with a weight average molecular weight of 500 to 100,000 and a content greater than 5 mg / L.

2. The method according to claim 1, wherein the copolymer is a copolymer of (meth)acrylic acid monomers and monomers containing an amide group and a sulfonic acid group or containing a hydroxyl group and a sulfonic acid group.

3. The method according to claim 1 or 2, wherein the film-forming amine is an aliphatic amine compound.

4. The method according to claim 1 or 2, wherein the phosphorus compound is a phosphonic acid compound.

5. The method according to claim 1 or 2, wherein when using the film-forming amine, the copolymer of (meth)acrylic acid monomers and sulfonic acid group-containing monomers is used in combination in the water system.

6. The method according to claim 1 or 2, wherein the water system is a cooling water system.

7. A metal corrosion inhibitor, which comprises a phosphorus compound, a film-forming amine, and a low molecular weight polymer with a weight average molecular weight of 500 to 100,000, wherein the polymer is included and used at an addition amount greater than 5 mg / L.

8. A water treatment agent for metal anti-corrosion, which comprises at least one of a phosphorus compound, a film-forming amine, and a copolymer of (meth)acrylic acid monomers and sulfonic acid group-containing monomers with a weight average molecular weight of 500 to 100,000, Among them, When used for metal anti-corrosion in a water system, the phosphorus compound, the film-forming amine, and the copolymer of (meth)acrylic acid monomers and sulfonic acid group-containing monomers are used in combination in the water system, and the copolymer is included and used at an addition amount greater than 5 mg / L.

9. A water treatment agent, which comprises a film-forming amine and / or a copolymer of (meth)acrylic acid monomers and sulfonic acid group-containing monomers with a weight average molecular weight of 500 to 100,000, Among them, When used in a water system, the water treatment agent is used by combining the film-forming amine with the copolymer of (meth)acrylic acid monomers and sulfonic acid group-containing monomers to enhance the metal anti-corrosion of the phosphorus compound, and the copolymer is included and used at an addition amount greater than 5 mg / L.

10. An anti-corrosion method for a water system, which is used to inhibit the corrosion of metals in contact with water, and the method includes using the reagent according to claim 7, 8, or 9.

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