Water-based corrosion prevention methods

Abstract

The present invention provides a technology relating to corrosion prevention of water systems for better suppressing corrosion of metals in contact with water. A corrosion prevention method for a water system for inhibiting corrosion of a metal in contact with the water system, comprising: A corrosion prevention method for an aqueous system, which uses a phosphorus compound, a film-forming amine, and a copolymer of a (meth)acrylic acid monomer and a sulfonic acid group-containing monomer, the copolymer having a weight-average molecular weight of 500 to 100,000, in the aqueous system. A metal corrosion inhibitor containing 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 an aqueous system, which uses the metal corrosion inhibitor to inhibit corrosion of metals in contact with water.

Description

Technical Field

[0001] The present invention relates to an aqueous corrosion prevention method, a metal corrosion inhibitor, a water treatment agent for metal corrosion prevention, a water treatment agent, and an aqueous corrosion prevention method for suppressing corrosion of metals in contact with water using these agents.

Background Art

[0002] For example, metal members (such as heat exchangers, reaction vessels, and pipes made of carbon steel, copper, or copper alloy) provided in an aqueous system such as an open circulation cooling water system are corroded by contacting with water (such as cooling water) in the aqueous system. Therefore, generally, corrosion prevention treatment is performed by adding chemicals. For example, in order to suppress corrosion of carbon steel heat exchangers, reaction vessels, and pipes in a cooling water system, a technique using a film-forming amine has been studied.

[0003] For example, Non-Patent Document 1 proposes a method using a film-forming amine as another method for suppressing corrosion. The method described in this Non-Patent Document 1 is mainly applied to the corrosion suppression of iron-based members in a boiler water system. In this Non-Patent Document 1, as the mechanism of corrosion prevention by the film-forming amine, it is disclosed that the film-forming amine adsorbs on the surface of the metal through an amino group to form a dense monolayer or multilayer film, thereby preventing the contact between the metal and water and suppressing the corrosion of the metal.

[0004] For example, in Patent Document 1, there is a corrosion prevention method in which a film-forming amine and an M alkalinity component are coexisted in a cooling water system to form a corrosion prevention film on the surface of a metal member in contact with the cooling water system to suppress the corrosion of the metal member. The method uses a neutral amine as the M alkalinity component, and adjusts the M alkalinity of the cooling water system during the initial treatment for forming the corrosion prevention film to 90 mg / L as CaCO3 or more.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] WO2019 / 078104 [Non-patent literature]

[0006] [Non-Patent Document 1] Corrosion Center News No. 054 (August 2010) Water Treatment Technology (1) "Corrosion and Corrosion Prevention of Boilers and Peripheral Equipment" Fumio Kawamura [Overview of the project] [Problems that the invention aims to solve]

[0007] However, conventionally, film-forming amines themselves have weak corrosion-preventive properties. Furthermore, when film-forming amines are used as scale removers in open-circulation cooling water systems, there have been cases where the corrosiveness of the materials in between has been a concern.

[0008] Therefore, the main objective of the present invention is to provide a water-based corrosion prevention technology for better suppressing the corrosion of metals that come into contact with water. [Means for solving the problem]

[0009] As a result of diligent research, the inventors have found that by using a combination of a phosphorus compound, a film-forming amine, and a polymer (preferably a (meth)acrylic acid copolymer and / or a low molecular weight polymer), the corrosion of metals in contact with water can be suppressed more effectively. Furthermore, they have found that by using the film-forming amine and the polymer in combination, the metal corrosion protection by the phosphorus compound can be further enhanced. In other words, the inventors have completed the following invention.

[0010] The present invention is a water-based corrosion prevention method for suppressing the corrosion of metals in contact with water. The present invention provides an aqueous corrosion prevention method that uses a phosphorus compound, a film-forming amine, and a copolymer of a (meth)acrylic acid monomer with a weight-average molecular weight of 500 to 100,000 and a sulfonic acid group-containing monomer at a concentration of more than 5 mg / L in the aqueous system.

[0011] Furthermore, the present invention comprises a phosphorus compound, a film-forming amine, and a low molecular weight polymer having a weight-average molecular weight of 500 to 100,000. The aforementioned polymer is included for use in amounts exceeding 5 mg / L. This product provides a metal corrosion inhibitor.

[0012] Furthermore, the present invention is a water treatment agent containing at least one of a phosphorus compound, a film-forming amine, or a copolymer of a (meth)acrylic acid monomer with a weight-average molecular weight of 500 to 100,000 and a sulfonic acid group-containing monomer. When used for water-based metal corrosion protection, the phosphorus compound, the film-forming amine, and the copolymer of the (meth)acrylic acid monomer and the sulfonic acid group-containing monomer are used in combination with the water system. The copolymer is included for use in amounts exceeding 5 mg / L. This product provides a water treatment agent for preventing metal corrosion.

[0013] Furthermore, the present invention is a water treatment agent containing a film-forming amine and / or a copolymer of a (meth)acrylic acid monomer with a weight-average molecular weight of 500 to 100,000 and a sulfonic acid group-containing monomer, and when used in an aqueous system, the film-forming amine and the copolymer of the (meth)acrylic acid monomer and the sulfonic acid group-containing monomer are used in combination to enhance metal corrosion protection by phosphorus compounds. The copolymer is included for use in amounts exceeding 5 mg / L. This product provides a water treatment agent.

[0014] The copolymer may be a copolymer of a (meth)acrylic acid monomer and a monomer containing an amide group or a hydroxyl group and a sulfonic acid group. The film-forming amine may be an aliphatic amine compound. The phosphorus compound may be a phosphonic acid compound. When using the film-forming amine in the aqueous system, a copolymer of the (meth)acrylic acid monomer and the sulfonic acid group-containing monomer may be used in combination. The aqueous system may be a cooling water system. The present invention can also provide an aqueous corrosion prevention method for suppressing corrosion of a metal in contact with water, including using the agent.

Effects of the Invention

[0015] According to the present invention, a technique related to aqueous corrosion prevention for better suppressing corrosion of a metal in contact with water can be provided. Note that the effects of the present invention are not necessarily limited to the effects described herein, and may be any of the effects described in this specification.

Brief Description of the Drawings

[0016] [Figure 1] It is a schematic diagram showing an example of the aqueous system used in the method of the present embodiment, for example, an example of a circulating cooling water system having a cooling tower, and the present invention is not limited thereto. [Figure 2] It is a schematic diagram of the rotary corrosion test apparatus used in this test.

Modes for Carrying Out the Invention

[0017] Hereinafter, preferred embodiments for carrying out the present invention will be described. Note that the embodiments described below show an example of typical embodiments of the present invention, and the scope of the present invention is not construed narrowly thereby. In this specification, percentages are expressed by mass (mass / mass%) unless otherwise specified. Also, the upper limit value (hereinafter) and the lower limit value (above) of each numerical range (~) can be arbitrarily combined as desired.

[0018] 1. Aqueous Metal Corrosion Prevention Method According to the Present Embodiment

[0019] The present invention provides a water-based corrosion prevention method for suppressing the corrosion of metals in contact with a water system, comprising using a phosphorus compound, a film-forming amine, and a polymer in the water system. The water-based corrosion prevention method may also be a water-based corrosion prevention treatment method. The polymer is preferably a low molecular weight and / or (meth)acrylic acid-based polymer, more specifically, low molecular weight polymers, (meth)acrylic acid-based polymers, and low molecular weight (meth)acrylic acid-based polymers, and it is preferable to select and use one or more of these. A more preferred polymer is a copolymer of a (meth)acrylic acid monomer with a weight-average molecular weight of 500 to 100,000 and a sulfonic acid group-containing monomer.

[0020] The present invention provides a water-based corrosion prevention technology for better suppressing the corrosion of metals in contact with water. Furthermore, the present invention provides a technology that can better enhance metal corrosion prevention by the phosphorus compound by using the film-forming amine in combination with the polymer, thereby reducing the amount of phosphorus compound or phosphorus used, and provides a water-based metal corrosion prevention treatment technology. The present invention provides a technology that can enhance the corrosion protection capability of metal materials used in water systems or cooling water systems (preferably circulating cooling water, more preferably open circulating cooling water systems). Furthermore, the present invention provides a technology that can enhance the corrosion protection capability of metal materials while scale removal in a water system is being carried out, thereby extending the lifespan of the metal materials.

[0021] In conventional technology, film-forming amines have been used to protect metal components in aqueous systems by adding them to water systems. For example, they have been proposed as corrosion inhibitors for steam in boilers, or as a combination of a copper corrosion inhibitor and acid consumption to enhance corrosion protection for metal materials. Furthermore, their use as on-line scale removers in open-circulation cooling water systems has also attracted attention. However, the corrosion-preventive power of film-forming amines themselves is weak, and there have been cases where the corrosiveness of materials during the period they are used as scale removers has been a concern.

[0022] In contrast, the present invention provides a technology that enhances corrosion resistance and suppresses corrosion of materials during scale removal by further using a low molecular weight and / or (meth)acrylic acid-based polymer when using a film-forming amine as a scale remover (preferably an on-line scale remover). In this specification, "On-Line" in "On-Line scale remover" refers to scale removal performed by operating the water system without stopping the operation of the water system (such as plant operation) (for example, continuous operation or circulation by a circulating water system). Furthermore, in this embodiment, by operating the water system, the chemicals used or the water containing the chemicals are in contact with the components of the water system (e.g., metal components, the inside of pipes, etc.) for the duration of the water system's operation. Therefore, both corrosion protection and scale suppression effects can be achieved.

[0023] The following describes this embodiment in detail.

[0024] In this embodiment, the material to be protected from corrosion is a metal material, although not particularly limited. Examples of such metal materials include one or more selected from carbon steel, copper, galvanized steel, zinc, aluminum, aluminum alloys, stainless steel, and alloys thereof. Among the metal materials, iron-based materials are preferred. Examples of such iron-based materials include all types of iron materials (e.g., pure iron, carbon steel, cast iron, etc.). More preferably, carbon steel materials commonly used for boilers and heat exchangers (e.g., STB steel pipes) are used. In JIS G 0203, carbon steel is defined as having a carbon content ranging from 0.02 mass% to approximately 2 mass%. More specifically, carbon steel with a carbon content of 0.25 mass% or less is called low-carbon steel, 0.25 to 0.6 mass% is called medium-carbon steel, and 0.6 mass% or more is called high-carbon steel. Since low-carbon to medium-carbon steel is widely used, carbon steel with a carbon content of 0.6 mass% or less is also called ordinary steel. Furthermore, cast iron is said to have a carbon content of more than 2% by mass. In this embodiment, ordinary steel, low-carbon steel, and medium-carbon steel, and more preferably low-carbon steel, can exhibit a better corrosion-preventive effect.

[0025] The corrosion protection treatment to which this embodiment is suitably applied is preferably applied to metal materials that come into contact with water or metal components that use metal materials that come into contact with water. Examples of locations or devices in aquatic systems that use metal materials or metal components include various types of piping such as water supply piping, pumps, flow paths, heat exchangers, refrigerators, etc., and one or more of these may be selected. More specifically, these or the metal parts or components they possess are the targets of the corrosion protection treatment to which this embodiment is suitably applied.

[0026] 1-1. Phosphorus Compounds The phosphorus compound used in this embodiment is preferably a phosphorus oxoacid compound having at least P(=O)(-OH). Examples of suitable phosphorus compounds include phosphonic acid compounds, phosphinic acid compounds, and phosphate compounds, from which one or more can be selected. These compounds may also be in the form of salts, and the salts are not particularly limited, with examples including alkali metals (e.g., sodium, potassium, etc.) and alkaline earth metals (e.g., calcium, magnesium, etc.), from which one or more can be used.

[0027] The phosphorus compound is preferably one that can be used in aqueous systems (preferably for water treatment such as corrosion prevention), and more preferably one that is water-soluble. The phosphorus compound is preferably one that has a scale-preventing effect, and is preferably one that can be used as a scale inhibitor for films. Furthermore, the phosphorus compound is preferably one that captures metal ions (for example, Ca or Al), and is preferably one that can be used as a phosphate compound-based scale inhibitor or a phosphonic acid compound-based scale inhibitor. The form of the phosphorus compound in this embodiment is not particularly limited and may be liquid, solid, or semi-solid, with liquid being preferred for ease of handling. In addition, the phosphorus compound used in this embodiment may be a commercially available product or one obtained by a known manufacturing method.

[0028] Of the aforementioned phosphorus compounds, organic phosphorus compounds are preferred, and phosphonic acid compounds are more preferred, from the viewpoint of exhibiting a better corrosion-preventive effect. When using organic phosphorus compounds (preferably phosphonic acid compounds), they may be used in combination with phosphoric acid compounds.

[0029] The phosphonic acid compound is preferably a compound having at least a phosphonic acid group, and is 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-hydroxyethylidenediphosphonic acid, aminotrimethylenephosphonic acid, ethylenediaminetetra(methylenephosphonic acid), diethylenetriaminepenta(methylenephosphonic acid), etc., and salts thereof, from which one or more can be selected. Of these, 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC) and / or 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP) are preferred. One or more can be used from these.

[0030] The phosphinic acid compound is a compound having at least a phosphinic acid group, and examples of phosphinates include bis(poly-2-carboxyethyl)phosphinic acid, phosphinocarboxylic acid copolymers, and salts thereof. Of these, phosphinocarboxylic acid salts are preferred. One or more of these can be used. Furthermore, one or more phosphorus compounds can be appropriately selected from the examples of phosphorus compounds described above.

[0031] The phosphate compound is preferably a compound containing at least a phosphate group, preferably a compound that can generate phosphate ions in an aqueous system, and more preferably an inorganic phosphate compound. Examples of the phosphate compound include phosphorus, phosphoric anhydride, phosphoric acid (also called orthophosphoric acid or orthophosphoric acid); polymerized phosphoric acid (for example, chain-like polyphosphates such as pyrophosphoric acid, tripolyphosphoric acid, orthopolyphosphoric acid, decametaphosphoric acid, etc.; cyclic polyphosphates such as hexametaphosphoric acid, etc.; and salts thereof), and one or more of these can be selected. The number of phosphorus atoms in the phosphate compound is not particularly limited, but is for example 1 to 10, and examples include orthophosphoric acid (1) and pyrophosphoric acid (2).

[0032] When the phosphorus compound is used in an aqueous system, the concentration used (mg PO4 / L, hereinafter referred to as "mg / L") is not particularly limited, but is preferably 0.1 to 10 mg / L, more preferably 3 to 6 mg / L, and it is preferable to add the phosphorus compound to achieve such a concentration. Furthermore, in a more preferable embodiment, when the phosphonic acid compound is used in an aqueous system, the concentration used (mg PO4 / L) is preferably 0.1 to 10 mg / L, more preferably 3 to 6 mg / L. Furthermore, the concentrations used for the phosphorus compounds, etc., as described above can also be appropriately adjusted by adopting the suitable upper and lower limits described in "1-4." below, "Amount of phosphorus compounds (preferably phosphonic acid compounds) used in aqueous systems." The concentration of phosphorus compounds (mg PO4 / L) can be determined using the molybdenum blue (ascorbic acid reduction) method (JIS K 0102 46.1.1).

[0033] 1-2. Film-forming amines The film-forming amine used in this embodiment is not particularly limited, but an amine capable of forming an effective corrosion-inhibiting protective film on metal materials in contact with water is preferred. The film-forming amine can be a film-forming amine that is commonly used as a corrosion inhibitor in aqueous systems such as boiler water systems or cooling water systems, or a film-forming amine that is generally used in aqueous systems. One or more aliphatic amine compounds (e.g., aliphatic monoamine compounds, aliphatic diamine compounds, etc.) can be used as the film-forming amine. In this specification, "aliphatic amine compounds" may be expressed as "aliphatic amines." Since film-forming amines are poorly soluble in water, they may be dissolved in an oil or dispersed in water as an emulsion.

[0034] In this embodiment, the corrosion protection can be enhanced by using at least the film-forming amine and the polymer in combination, which has the advantage of being able to suppress corrosion on materials (e.g., metal materials) during scale removal. Moreover, when the film-forming amine is used as an on-line scale remover, it has the advantage of exhibiting an even better corrosion protection effect.

[0035] The aliphatic amine compound (aliphatic amines) preferably has one or two nitrogen atoms and an aliphatic group bonded to at least one nitrogen atom. The aliphatic amine compound (aliphatic amines) is not particularly limited and includes aliphatic amines, their salts, and derivatives thereof, and one or more selected from these can be used. More preferred examples include aliphatic monoamine compounds and aliphatic diamine compounds, and one or more selected from these can be used.

[0036] The aliphatic amine compound (aliphatic amines) is preferably a long-chain aliphatic amine compound (long-chain aliphatic amines). The number of carbon atoms in the long-chain aliphatic group is not particularly limited as long as it can form a corrosion-preventive film, and is preferably 10 to 22, more preferably 12 to 20, and even more preferably 16 to 18. When the number of carbon atoms is 10 or more, it is easy to form a film on metal members and the corrosion-inhibiting function can be effectively exhibited. When the number of carbon atoms is 22 or less, it tends to be easier to handle when the chemical is injected.

[0037] The aliphatic groups constituting the aliphatic amine compound (aliphatic amines) may contain unsaturated bonds. Furthermore, the amino groups constituting the aliphatic amine compound may have their hydrogen atoms appropriately substituted with hydrocarbon groups such as methyl or ethyl groups. In addition, the aliphatic amine may be a fatty acid salt (for example, a mixed amine compound). In this case, the fatty acid portion constituting the fatty acid salt can be one or more selected from, for example, oleic acid, lauric acid, and stearic acid. When the aliphatic amine compound is a fatty acid salt, one or more selected from, for example, animal fats and oils, vegetable fats and oils, and microbial fats and oils may be used as the raw material, with animal and vegetable fats and oils being preferred.

[0038] Suitable specific examples of the aliphatic amine compound (aliphatic amines) include saturated aliphatic amine compounds (alkylamines), unsaturated aliphatic amine compounds (alkynylamines), mixed amine compounds (e.g., coconut oil amine, hardened beef tallow amine, etc.), and alkylene oxide adducts of aliphatic amine compounds. One or more selected from these can be used. Furthermore, "alkylene oxide adducts of aliphatic amine compounds" include those obtained by addition polymerization of ethylene oxide or propylene oxide to aliphatic mixed amines, etc.

[0039] The aliphatic group in the aliphatic amine compound may be acyclic or cyclic, and more specifically, it may be linear (linear or branched) or alicyclic (non-aromatic ring), but linear is preferred. The aliphatic group is preferably a saturated aliphatic group, more preferably an alkyl group or alkylene group, which may have substituents as appropriate.

[0040] Examples of the composition of the aliphatic monoamine compound include, but are not limited to, "aliphatic group-amino group". Examples of the composition of the aliphatic diamine compound include, but are not limited to, a compound in which at least one hydrogen atom of an amino group is substituted with an aliphatic group, and which has a divalent aliphatic group between the nitrogen atom of one amino group and the nitrogen atom of the other amino group. Examples of aliphatic diamine compounds include, for example, "amino group-divalent aliphatic group-amino group", and it is preferable that at least one of the amino groups is "aliphatic group-amino group", for example, "RR'N-divalent aliphatic group-NH2" such as trimethylenediamine (also called "diaminopropane"). The divalent aliphatic group may be linear (linear, branched) or alicyclic, but is preferably linear. "Amino group" 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, one may be hydrogen and the other an alkyl group, and they may each be the same or different alkyl groups.

[0041] The divalent aliphatic group is preferably a divalent saturated or unsaturated hydrocarbon group, more preferably a divalent saturated hydrocarbon group, and even more preferably a chain-like C1-C4 alkylene group (preferably a methylene group or ethylene group), such as -(CH2)n- (wherein n=1-4), or, for example, a diethylene group (n=2), a triethylene group (n=3), and so on.

[0042] Examples of the aliphatic amine compounds (preferably long-chain aliphatic amine compounds) 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.), and mixed monoamine compounds (e.g., coconut oil amine, hydrogenated beef tallow amine). Examples include diamino compounds having an aliphatic group on an amino group (for example, alkylpropanediamine (preferably with 16 to 18 carbon atoms in the alkyl group), N,N-diethyl-1,3-propanediamine, N-oleyl-1,3-diaminopropane, N-tarou-1,3-diaminopropane, N-coco-1,3-diaminopropane, etc.); alkylene oxide adducts such as N-tarou-1,3-diaminopropane-ethylene oxide adducts, and one or more selected from these can be used.

[0043] Among the aliphatic amine compounds (aliphatic amines), aliphatic monoamine compounds and / or aliphatic diamine compounds are preferred, more preferably aliphatic diamine compounds, and furthermore, long-chain aliphatic compounds are preferred.

[0044] The concentration (mg / L, hereinafter referred to as "mg / L") used when the film-forming amine (preferably an aliphatic amine compound, more preferably an aliphatic diamine compound) is used in an aqueous system is not particularly limited, but is preferably 5 to 70 mg / L, more preferably 10 to 50 mg / L, and it is preferable to add the film-forming amine to such a concentration, and this concentration may also be the concentration used for online use. Furthermore, in a more preferred embodiment, the concentration used when an aliphatic diamine compound is used in an aqueous system is more preferably 5 to 70 mg / L, and even more preferably 10 to 50 mg / L. Furthermore, the concentration of the film-forming amine, etc. used as described above can also be appropriately determined by adopting the preferred upper and lower limits described in "1-4." below, "Amount of film-forming amine (preferably an aliphatic amine compound, more preferably an aliphatic diamine compound) used in the aqueous system."

[0045] 1-3. Polymers The polymer used in this embodiment is not particularly limited, but organic polymer compounds that can be used in aqueous systems are preferred, and more preferably low molecular weight polymers and / or water-soluble polymers. Among the polymers used in this embodiment, (meth)acrylic acid polymers are preferred, more preferably (meth)acrylic acid polymers containing sulfonic acid groups in the molecule, and even more preferably (meth)acrylic acid polymers containing sulfonic acid groups in the molecule, of which AA / AMPS polymers and AA / HAPS polymers are preferred. Furthermore, the polymer used in this embodiment may be a homopolymer obtained from the same monomer, but copolymers obtained using different monomers are preferred. The polymer used in this embodiment can preferably be a polymer used as a scale inhibitor in cooling water systems. The form of the polymer salt is not particularly limited, but salts that can make monomers or polymers into water-soluble salts are preferred, and 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 and primary to tertiary amines, and one or more selected from these can be used.

[0046] The polymer used in this embodiment is a homopolymer or copolymer obtained by polymerizing or copolymerizing one or more monomers selected from the group consisting of (meth)acrylic acid compounds such as (meth)acrylic acid (acrylic acid and / or methacrylic acid), 2-hydroxyethyl methacrylate (HEMA); monomers containing sulfonic acid groups such as 1-propanesulfonic acid (HAPS), 2-acrylamido-2-methylpropanesulfonic acid (AMPS), styrenesulfonic acid (SS), isoprenesulfonic acid (IPS); isobutylene (IB); and maleic acid. Monomers of (meth)acrylic acid compounds other than (meth)acrylic acid may also be used, for example, (meth)acrylic acid compounds having esters, hydroxyl groups, amino groups, etc., but (meth)acrylic acid is preferred.

[0047] Of the polymers mentioned above, (meth)acrylic acid-based polymers are preferred, and more preferably copolymers of (meth)acrylic acid monomers and sulfonic acid monomers. 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), 2-acrylamido-2-methylpropanesulfonic acid (AMPS), etc.

[0048] The weight-average molecular weight of the polymer (preferably a (meth)acrylic acid-based polymer) is not particularly limited, but is preferably low. A suitable lower limit is preferably 500 or more, more preferably 1,000 or more, more preferably 4,000 or more, and more preferably 5,000 or more. A suitable upper limit 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, a more suitable numerical range is more preferably 500 to 100,000, more preferably 1,000 to 50,000, more preferably 4,000 to 30,000, and more preferably 5,000 to 20,000. The weight-average molecular weight of polymers 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 value is expressed in terms of sodium polyacrylate.

[0049] 1-3-1. (Meth)acrylic acid polymers The polymer used in this embodiment is preferably a (meth)acrylic acid polymer, more preferably a (meth)acrylic acid copolymer, and more specifically, preferably a copolymer of a (meth)acrylic acid monomer and a sulfonic acid group-containing monomer, and even more preferably a copolymer of a (meth)acrylic acid monomer and an amide group and a sulfonic acid group-containing monomer. The monomer ratio (molar ratio (mol%)) of the (meth)acrylic acid monomer to the sulfonic acid group-containing monomer in the (meth)acrylic acid copolymer is preferably 99 to 1:1 to 99. The (meth)acrylic acid copolymer is preferably low molecular weight.

[0050] <(meth)acrylic acid monomer> The (meth)acrylic acid monomer is not particularly limited, but examples include (meth)acrylic acid and its salts, and one or more selected from this group can be used. In this embodiment, "(meth)acrylic acid" means at least one selected from the group consisting of "acrylic acid" and "methacrylic acid". Of these, acrylic acid or its salts are preferred. If the (meth)acrylic acid monomer used in this embodiment contains a sulfonic acid group, it is preferable to use this monomer as a sulfonic acid monomer, and it is more preferable to use a monomer other than a (meth)acrylic acid monomer containing a sulfonic acid group as the (meth)acrylic acid monomer used in this embodiment.

[0051] <Sulfonic acid monomer> The sulfonic acid monomer is not particularly limited, but a monomer containing a sulfonic acid group is preferred from the viewpoint of exhibiting a better corrosion-preventive effect, and an unsaturated monomer is even more preferred. Examples of the sulfonic acid monomer include, but are not limited to, monoethylene unsaturated sulfonic acid monomers and their salts, among which monoethylene unsaturated sulfonic acid monomers are preferred.

[0052] Examples of the sulfonic acid monomers include monomers having an amide group and a sulfonic acid group (preferably those with 6 to 9 carbon atoms), monomers containing a hydroxyl group and a sulfonic acid group (preferably those with 6 to 9 carbon atoms), sulfonates of aliphatic conjugated dienes (preferably those with 4 to 15 carbon atoms), and salts thereof. One or more selected from this group can be used. Of these, monomers having an amide group and a sulfonic acid group (preferably those with 6 to 9 carbon atoms) and monomers containing a hydroxyl group and a sulfonic acid group (preferably those with 6 to 9 carbon atoms) are preferred. Furthermore, the "sulfonic acid group" of the monomer may be a sulfonic acid group that may have substituents, for example, an alkyl sulfonic acid group, where the number of carbon atoms in the "alkyl" of the alkyl sulfonic acid group is preferably 1 to 8, and a methylpropanesulfonic acid group (also called a tert-butylsulfonic acid group) is more preferred. This allows for a better corrosion protection effect.

[0053] Examples of monomers having the amide group and sulfonic acid group include (meth)acrylamide alkylpropanesulfonic acid and crotonamide alkylpropanesulfonic acid. More specifically, examples include 2-acrylamide-2-methylpropanesulfonic acid (AMPS), 3-acrylamide-3,3-dimethylpropanesulfonic acid, 2-methacrylamide-2-methylpropanesulfonic acid, 3-methacrylamide-3,3-dimethylpropanesulfonic acid, and salts thereof. One or more selected from this group can be used.

[0054] Examples of monomers containing the hydroxyl group and sulfonic acid group include 3-alyloxy-2-hydroxy-1-propanesulfonic acid (HAPS), 3-methacryloxy-2-hydroxypropanesulfonic acid, 3-alyloxy-1-hydroxypropane-2-sulfonic acid, 3-methacrooxy-1-hydroxypropane-2-sulfonic acid, and salts thereof. One or more selected from this group can be used.

[0055] Examples of sulfonates of the aliphatic conjugated diene include sulfonates of 1,3-butadiene and sulfonates of 2,3-dimethyl-1,3-butadiene, and one or more selected from this group can be used.

[0056] More suitable sulfonic acid monomers include unsaturated monomers containing sulfonic acid groups such as (meth)acrylamide-methylpropanesulfonic acid, 3-allyloxy-2-hydroxypropanesulfonic acid, (meth)allylsulfonic acid, vinylsulfonic acid, styrenesulfonic acid, and 2-sulfoethyl methacrylate, as well as their salts. One or more selected from this group can be used. Of these, at least one monomer selected from 2-acrylamide-2-methylpropanesulfonic acid (AMPS) and 3-allyloxy-2-hydroxypropanesulfonic acid (HAPS) is preferred, with AMPS and / or HAPS being more preferred. This allows for a better corrosion protection effect.

[0057] <Examples of (meth)acrylic acid polymer production> The (meth)acrylic acid copolymer can be produced by known manufacturing methods. A preferred copolymer is a polymer obtained by copolymerizing (i) a (meth)acrylic acid monomer and (ii) one or more sulfonic acid monomers selected from monomers having an amide group and a sulfonic acid group, monomers containing a hydroxyl group and a sulfonic acid group, etc., in a predetermined mass usage ratio. Any monomer may be used as long as it does not impair the effects of the present invention.

[0058] A more preferred (meth)acrylic acid copolymer is a polymer obtained by copolymerizing (i) an acrylic acid monomer and (ii) at least one sulfonic acid monomer selected from 2-acrylamido-2-methylpropanesulfonic acid and 3-alyloxy-2-hydroxypropanesulfonic acid in a predetermined mass ratio. A more preferable (meth)acrylic acid copolymer is one or more selected from the group consisting of copolymers of acrylic acid monomer and 2-acrylamido-2-methylpropanesulfonic acid monomer, copolymers of acrylic acid monomer and 3-alyloxy-2-hydroxypropanesulfonic acid monomer, etc. In this case, the predetermined molar ratio of the more preferable (meth)acrylic acid monomer to the sulfonic acid monomer is, for example, 1 to 99:99 to 1, and the molar ratio can be appropriately adopted from the <Molar Ratio (mol%) in the (meth)acrylic acid copolymer> described later. This makes it possible to obtain a polymer that exhibits a better corrosion protection effect.

[0059] <Molar ratio (mol%) of the (meth)acrylic acid monomer and the sulfonic acid monomer> The molar ratio (mol%: when the total amount of both is 100) of (meth)acrylic acid monomer to sulfonic acid monomer in the copolymer of component (A) (meth)acrylic acid monomer and sulfonic acid monomer is not particularly limited, but a preferred lower limit for (meth)acrylic acid monomer is preferably 10 or more, more preferably 40 or more, even more preferably 50 or more, more preferably 60 or more, more preferably 70 or more, more preferably 75 or more, and more preferably 80 or more. A preferred upper limit for (meth)acrylic acid monomer is preferably 99 or less, more preferably 98 or less, even more preferably 95 or less, more preferably 93 or less, and even more preferably 90 or less. A more preferred numerical range for the molar ratio of acrylic acid monomer to sulfonic acid monomer is more preferably 50~99:50~1, even more preferably 60~95:40~5, and more preferably 75~90:25~10. By setting the above component (A) copolymer to these molar ratios, a better corrosion protection effect can be achieved. The molar ratio may be appropriately used for the respective molar ratios (%) of (meth)acrylic acid monomer and sulfonic acid monomer to constitute copolymers such as AA / AMPS polymers and AA / HAPS polymers, as described later.

[0060] As a more preferred embodiment of the molar ratio of the copolymer, in a copolymer of a (meth)acrylic acid monomer and a sulfonic acid monomer containing an amide group and / or a hydroxyl group, the molar ratio (mol%) of the (meth)acrylic acid monomer to the sulfonic acid monomer containing the amide group and / or hydroxyl group is more preferably 60-95:40-5, and more preferably 75-90:25-10. By using this molar ratio, a better corrosion protection effect can be achieved. The preferred lower limit and preferred upper limit of the "molar ratio of (meth)acrylic acid monomer to sulfonic acid monomer" described above can be appropriately adopted.

[0061] Furthermore, in the case of AA / AMPS polymers and AA / HAPS polymers, a more preferred molar ratio of the copolymer is, preferably, (AA) 50-99:50-1, more preferably (AA) 60-95:40-5, and more preferably (AA) 75-90:25-10. By using this molar ratio, a better corrosion protection effect can be achieved. The molar ratio can be appropriately selected from the preferred lower and upper limits of the "molar ratio of (meth)acrylic acid monomer to sulfonic acid monomer" mentioned above.

[0062] <Weight-average molecular weight of (meth)acrylic acid copolymers> The weight-average molecular weight of a copolymer of (meth)acrylic acid monomer and sulfonic acid monomer, determined by GPC, is not particularly limited, but its preferred lower limit is preferably 500 or more, more preferably 1,000 or more, even more preferably 2,000 or more, more preferably 3,000 or more, even more preferably 4,000 or more, and more preferably 5,000 or more. Its preferred upper limit is preferably 100,000 or less, more preferably 50,000 or less, even more preferably 40,000 or less, more preferably 30,000 or less, and more preferably 20,000 or less. The preferred numerical range for the (meth)acrylic acid monomer and sulfonic acid monomer is more preferably 4,000 to 30,000, and preferably 5,000 to 20,000. Furthermore, while the preferred weight-average molecular weights of the AA / AMPS polymer and AA / HAPS polymer can be appropriately determined by adopting the preferred lower and upper limits mentioned above, 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 corrosion protection effect can be achieved.

[0063] When the polymer (preferably a low molecular weight and / or (meth)acrylic acid-based polymer) is used in an aqueous system, the concentration used (mg solid / L, hereinafter referred to as "mg / L") is not particularly limited, but is preferably 3 to 30 mg / L, more preferably 5 to 20 mg / L, and even more preferably 6 to 20 mg / L, and it is preferable to add the polymer to achieve such a concentration. Furthermore, in a preferred embodiment, when the (meth)acrylic acid-based polymer (more preferably a (meth)acrylic acid-based polymer containing a sulfone group) is used in an aqueous system, the concentration used is not particularly limited, but is preferably 3 to 30 mg / L, more preferably 5 to 20 mg / L, and even more preferably 6 to 20 mg / L. Also, when the AA / AMPS-based polymer and / or the AA / HAPS-based polymer is used in an aqueous system, the concentration used is not particularly limited, but is preferably 3 to 30 mg / L, more preferably 5 to 20 mg / L, and even more preferably 6 to 20 mg / L. Furthermore, the concentration of the polymers, etc., used as described above can also be appropriately adjusted by adopting the preferred upper and lower limits described in "1-4." below, "Amount of the polymer (preferably low molecular weight and / or (meth)acrylic acid-based polymers) used".

[0064] 1-4. Combined use of the phosphorus compound, the film-forming amine, and the polymer, suitable amounts and ratios of each component, etc. In this embodiment, in a water-based corrosion prevention method for suppressing the corrosion of metals in contact with a water system, by using at least the three components of the phosphorus compound, the film-forming amine, and the polymer, and by having these three components present in the water system, a better metal corrosion prevention effect can be achieved. The following describes the more suitable amounts and proportions of each component to be used in the water system, or the content ratio and blending ratio in the chemical agent.

[0065] Furthermore, in another aspect of this embodiment, by using the film-forming amine and the polymer in combination with an aqueous system, a technique can be provided to enhance metal corrosion protection by phosphorus compounds present in or used in the aqueous system. A better mass usage ratio or mass content ratio in the chemical will be described below.

[0066] The operating period in the aqueous system in this embodiment is not particularly limited, but it may be operated for a longer period to better exhibit or maintain the corrosion prevention effect. A suitable lower limit is, for example, 0.5 months or more, preferably 1 month or more, more preferably 2 months or more, and more preferably 3 months or more. A suitable upper limit is not particularly limited, but preferably 6 months or less, more preferably 5 months or less, and more preferably 4 months or less. A suitable numerical range is more preferably 2 to 4 months. During this period, it is preferable to operate in such a way that the film-forming amine and the polymer are in contact with the metal material at least continuously or cyclically. The operating period may also be the usage period.

[0067] <Suitable amounts of the phosphorus compound, the film-forming amine, and the polymer to be used> In this embodiment, "concentration used (mg / L)" may be "amount used (mg / L)" or "amount added (mg / L)", "amount used (mg / L)" may be "concentration used (mg / L)" or "amount added (mg / L)", and "amount added (mg / L)" may be "concentration used (mg / L)" or "amount used (mg / L)".

[0068] The amount of the phosphorus compound (preferably a phosphonic acid compound) used in the aqueous system (mg PO4 / L, hereinafter referred to as "mg / L") is not particularly limited, but a suitable lower limit is preferably 0.1 mg / L or more, more preferably 0.5 mg / L or more, even more preferably 1 mg / L or more, more preferably 2 mg / L or more, and more preferably 3 mg / L or more. A suitable upper limit is not particularly limited, but from the viewpoint of balancing the reduction of the amount of agent used and the exertion of corrosion prevention effect, it is preferably 20 mg / L or less, more preferably 15 mg / L or less, even more preferably 10 mg / L or less, more preferably 8 mg / L or less, and more preferably 5 mg / L or less. A suitable numerical range is more preferably 0.1 to 10 mg / L, and even more preferably 3 to 6 mg / L.

[0069] In a more preferred embodiment, the amount of the phosphonic acid compound used in the aqueous system (mg PO4 / L) can be appropriately set to the preferred lower and upper limits of the amount of the phosphorus compound used, but a more preferred numerical range is more preferably 0.1 to 10 mg / L, and even more preferably 1 to 5 mg / L.

[0070] Furthermore, in a more preferred embodiment of this design, the phosphorus compound described above is preferably used continuously or discontinuously in an aqueous system (preferably a cooling water system), and is more preferably added to blowdown water.

[0071] The amount (mg / L, hereinafter referred to as "mg / L") used in the aqueous system of the film-forming amine (preferably an aliphatic amine compound, more preferably an aliphatic diamine compound) is not particularly limited, but a suitable lower limit is preferably 0.1 mg / L or more, more preferably 0.5 mg / L or more, even more 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 even more preferably 10 mg / L or more. A suitable upper limit is not particularly limited, but from the viewpoint of balancing the reduction of the amount of agent used and the exertion of corrosion prevention effect, it is preferably 100 mg / L or less, more preferably 80 mg / L or less, even more preferably 70 mg / L or less, more preferably 60 mg / L or less, and even more preferably 50 mg / L or less. A suitable numerical range is more preferably 5 to 70 mg / L, and even more preferably 10 to 50 mg / L.

[0072] Furthermore, in a more preferred embodiment of this design, the film-forming amine described above is preferably used continuously or discontinuously in an aqueous system (preferably a cooling water system), and more preferably added continuously or discontinuously to blowdown water, and more preferably added continuously to blowdown water in order to synergistically enhance the corrosion-preventive effect of the film-forming amine when used in combination with the polymer.

[0073] The amount of the polymer (preferably low molecular weight and / or (meth)acrylic acid-based polymer) used in the aqueous system (mg solid / L, hereinafter referred to as "mg / L") is not particularly limited, but a suitable lower limit is preferably 0.5 mg / L or more, more preferably 1 mg / L or more, even more preferably 2 mg / L or more, more preferably 4 mg / L or more, more preferably 5 mg / L or more, more preferably more 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. A suitable upper limit is not particularly limited, but from the viewpoint of balancing the reduction of the amount of chemical used and the exertion of corrosion protection effects, it is preferably 100 mg / L or less, more preferably 50 mg / L or less, even more 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, even more preferably 5 to 20 mg / L or 6 to 30 mg / L, and even more preferably 6 to 20 mg / L.

[0074] In a more preferred embodiment, the amount (mg solid / L) of low molecular weight and / or (meth)acrylic acid-based polymer used in the aqueous system can be appropriately set to the preferred lower and upper limits of the above-mentioned polymer usage, but a more preferred numerical range is more preferably 3 to 30 mg / L, even more preferably 5 to 20 mg / L or 6 to 30 mg / L, and even more preferably 6 to 20 mg / L. In a more preferable embodiment, the amount (mg solid / L) of the (meth)acrylic acid polymer containing sulfonic acid groups used in the aqueous system can be appropriately selected from the preferred lower and upper limits of the amount of the polymer used, but a more preferable numerical range is more preferably 3 to 30 mg / L, even more preferably 5 to 20 mg / L or 6 to 30 mg / L, and even more preferably 6 to 20 mg / L. Furthermore, in a more preferable embodiment, the amount (mg solid / L) of the AA / AMPS polymer and / or the AA / HAPS polymer used in the aqueous system can be appropriately selected from the preferred lower and upper limits of the amount of the polymer used, but a more preferable numerical range is more preferably 3 to 30 mg / L, even more preferably 5 to 20 mg / L or 6 to 30 mg / L, and even more preferably 6 to 20 mg / L.

[0075] Furthermore, in a more preferred embodiment of this design, the polymer described above is preferably used continuously or discontinuously in a water system (preferably a cooling water system), and is more preferably added to blowdown water.

[0076] <Preferred usage ratio or blending ratio of the phosphorus compound, the film-forming amine, and the polymer>

[0077] The proportion of the film-forming amine and the polymer used in the aqueous system or the blending ratio in the drug is not particularly limited, but may be determined by appropriately combining the amounts (mg / L) used in each aqueous system as described above. The preferred range for the usage ratio or blending ratio is preferably 5-70:3-30 or 6-30, more preferably 10-50:5 or 6-20. Examples of such combinations include, but are not limited to, combinations of aliphatic amine compounds (e.g., aliphatic diamine compounds, etc.) and low molecular weight (meth)acrylic acid monomers and sulfonic acid group-containing monomers (e.g., the AA / AMPS polymer, the AA / HAPS polymer, etc.).

[0078] Furthermore, the proportion of phosphorus compounds and the film-forming amines used in the aqueous system or their blending ratio in the drug is not particularly limited, but may be determined by appropriately combining the amounts (mg / L) used in each aqueous system as described above. A preferred range for the proportion of use or blending ratio is preferably 0.1 to 10 parts phosphorus compounds to 5 to 70 parts film-forming amines, and more preferably 1 to 5 parts phosphorus compounds to 10 to 50 parts film-forming amines. Examples of such combinations include, but are not limited to, combinations of phosphonic acid compounds and aliphatic amine compounds (e.g., aliphatic diamine compounds).

[0079] Furthermore, the proportion of phosphorus compounds and the polymer used in the aqueous system or the blending ratio in the drug is not particularly limited, but may be determined by appropriately combining the amounts (mg / L) used in each aqueous system as described above. A preferred range for the proportion of use or blending ratio is preferably 0.1 to 10 parts phosphorus compound to 3 to 30 or 6 to 30 parts polymer, and more preferably 1 to 5 parts phosphorus compound to 5 or 6 to 20 parts polymer. A preferred example of such a combination is, but is not limited to, a combination of a phosphonic acid compound with a low molecular weight (meth)acrylic acid monomer and a sulfonic acid group-containing monomer (for example, the AA / AMPS polymer, the AA / HAPS polymer, etc.).

[0080] Furthermore, the proportion of phosphorus compounds, the film-forming amines, and the polymers used, or their blending ratio in the drug, is not particularly limited, but may be determined by appropriately combining the amounts (mg / L) used in each aqueous system as described above. A preferred range for the proportion of use or blending ratio is preferably 0.1-10 of the phosphorus compound, 5-70 of the film-forming amine, and 3-30 or 6-30 of the polymer, and more preferably 1-5 of the phosphorus compound, 10-50 of the film-forming amine, and 5 or 6-20 of the polymer. Suitable examples of such combinations include, but are not limited to, combinations of phosphonic acid compounds, aliphatic amine compounds (e.g., aliphatic diamine compounds, etc.), low molecular weight (meth)acrylic acid monomers, and sulfonic acid group-containing monomers (e.g., the AA / AMPS polymer, the AA / HAPS polymer, etc.).

[0081] <Optional ingredients> In this embodiment, in addition to the components described above (specifically, the film-forming amine, the polymer, and the phosphorus compound), optional components may be used in the aqueous system or included in the chemical, as appropriate, within the limits that do not impair the effects of the present invention. The optional components are not particularly limited, but for example, one or more selected from the group consisting of pH adjusters, defoaming agents, corrosion inhibitors other than the above components, scale inhibitors, fungicides, algaecides, etc. may be used.

[0082] In this embodiment, in addition to the combined use of the film-forming amine and the polymer described above, or the combined use of these components with the phosphorus compound, it is preferable to further include a scale inhibitor other than those described above in the aqueous system. Examples of such scale inhibitors include maleic acid polymers and their salts, polyaspartic acid and its salts, and one or more selected from these can be used.

[0083] Furthermore, in this embodiment, in addition to the combined use of the film-forming amine and the polymer described above, or the combined use of these components and the phosphorus compound, it is preferable to also include a slime control agent other than those described above in the aqueous system. The slime control agent is not particularly limited, but examples include hypochlorous acid and its salts, chlorine gas, hypobromous acid and its salts, stabilized chlorine, stabilized bromine, organic disinfectants, etc., and one or more selected from these can be used.

[0084] In this embodiment, in addition to the combined use of the film-forming amine and the polymer described above, or the combined use of these components and the phosphorus compound, it is preferable to further include a corrosion inhibitor other than these components (more preferably a corrosion-resistant metal compound) in the aqueous system. A corrosion-resistant metal compound is a metal compound used for corrosion prevention, and the metal compound is a metal compound that can easily release heavy metal ions into water, and is not particularly limited as long as it is a metal compound that can exert this effect.

[0085] The aforementioned "corrosion inhibitors other than these components" are not particularly limited, but include, for example, corrosion-inhibiting metal compounds such as zinc salts, tin salts, manganese salts, aluminum and aluminates; organic acid compounds, polyaspartic acid and its salts, polyitaconic acid and its salts, amino acid compounds, etc., and one or more selected from the group consisting of these can be used. Of these, corrosion-inhibiting metal compounds are more preferably used, and among these corrosion-inhibiting metal compounds, zinc salts and / or tin salts are preferred, and zinc salts are even more preferred. In the case of the "phosphorus compounds" mentioned above, if a phosphate compound is selected, it is desirable to exclude phosphate compounds from the aforementioned "corrosion inhibitors other than these components," and if a phosphonic acid compound is selected, a phosphate compound may be selected from the aforementioned "corrosion inhibitors other than these components." Furthermore, suitable "corrosion inhibitors other than these components" that can be used in combination include one or more selected from phosphate compounds (such as orthophosphate, PBTC, hexanemetaphosphate), zinc salts (such as zinc chloride, zinc sulfate), and copper corrosion inhibitors (such as benzotriazole / tolyltriazole), which are commonly used in cooling water systems.

[0086] The amount of the aforementioned "corrosion inhibitors other than these components" used (mg soild / L, hereinafter referred to as "mg / L") is not particularly limited, but a suitable lower limit is preferably 0.1 mg / L or more, more preferably 0.5 mg / L or more, and a suitable upper limit is preferably 5 mg / L or less, more preferably 4 mg / L or less, even more preferably 3 mg / L or less, and more preferably 2 mg / L or less. By having the aforementioned component (C) corrosion inhibitor present in an aqueous system in a suitable amount, a corrosion inhibitory effect equivalent to or better than the combined effect of the aforementioned component (A) copolymer and the aforementioned component (B) maleic acid polymer can be exhibited more effectively. As a result, when obtaining a corrosion inhibitory effect equivalent to that of the aforementioned components (A) and (B), it is possible to further reduce the amounts of each of the aforementioned components (A) and (B) by adding the aforementioned component (C).

[0087] 1-5. Water-based metal corrosion protection methods As described above, the aqueous metal corrosion protection method in this embodiment can use a combination of the film-forming amine, the polymer, and the phosphorus compound, and it is preferable that these three components are present in the aqueous system at the same time. In this embodiment, these components may be added to the aqueous system continuously or intermittently. In this embodiment, these components can be added to the aqueous system at the same time or at different times. The aqueous system may be equipped with one or more chemical injection devices for adding the chemicals (components) to the aqueous system. The chemical injection device may add the components individually, a mixture of two components and the other component, or a mixture of three components at the same time or at different times, so that these three components are present in the aqueous system at the same time. As a preferred example of this embodiment, it is preferable to have the film-forming amine present in the aqueous system as an on-line scale remover, and to adjust the system so that these three components are present in the aqueous system at the same time. Furthermore, this embodiment does not limit the location for mixing these components to a tank (e.g., a pit) such as a chemical storage tank or chemical mixing tank that can be provided in a water system, such as a water system flow path (e.g., a circulating water channel) or piping. In addition, the water system may be appropriately equipped with measuring devices capable of measuring the concentration of each chemical (concentration of each component) in the water system, and measuring devices capable of measuring the water quality of the water system. In this embodiment, these measurement results may be transmitted to a control unit, and the control unit may control and manage the method of this embodiment or its steps and operations.

[0088] In this embodiment, the water-based metal corrosion prevention method is preferably characterized by the combined use of the film-forming amine and the polymer, or the combined use of the film-forming amine, the polymer, and the phosphorus compound, in a predetermined mass usage ratio or mass content ratio within the water system.

[0089] In this embodiment, the film-forming amine and the polymer can be used in combination, or the film-forming amine, the polymer, and the phosphorus compound can be used in combination, either as a one-component drug or as a multi-component drug (e.g., a combination product), and can be added to an aqueous system. As another aspect of this embodiment, a method for preventing corrosion in an aqueous system can also be provided by adding a water treatment agent containing at least one of the phosphorus compound, the film-forming amine, or the polymer to the aqueous system, thereby making the phosphorus compound, the film-forming amine, and the polymer present in the aqueous system.

[0090] Furthermore, the three components may be added to the aqueous system simultaneously or separately, either by combining the film-forming amine and the polymer, or by combining the film-forming amine, the polymer, and the phosphorus compound, so that all three components are present in the aqueous system. The addition of each of the three components may be continuous or intermittent.

[0091] In this embodiment, a more preferred embodiment may also be provided, which uses (i) a metal corrosion protection agent, (ii) a water treatment agent, or (iii) a water treatment agent or combination product for metal corrosion protection. In this specification, a combination product may be referred to as a product set or a kit product. (i) A metal corrosion inhibitor comprising a phosphorus compound, a film-forming amine, and a polymer. (ii) A water treatment agent containing a film-forming amine and / or a polymer, A water treatment agent used in water systems, which is used in combination with the film-forming amine and the polymer to enhance metal corrosion protection by phosphorus compounds. (iii) A water treatment agent containing at least one of a phosphorus compound, a film-forming amine, or a polymer, A water treatment agent for metal corrosion prevention, used in combination with a phosphorus compound, a film-forming amine, and a polymer when used in a water-based metal corrosion prevention system. The water treatment agent may also be a combination product for water treatment agents, comprising at least one, two, or three selected from a first water treatment agent containing the phosphorus compound, a second water treatment agent containing the film-forming amine, and a third water treatment agent containing the polymer. In a more preferred embodiment, it is preferable that the above-mentioned metal corrosion inhibitor, water treatment agent, third water treatment agent, etc., contain or are configured to include the polymer (preferably a copolymer of the (meth)acrylic acid monomer and the sulfonic acid group-containing monomer) in an amount of 6 mg / L or more when used in an aqueous system.

[0092] The water system to which this embodiment is applied is not particularly limited and includes, for example, cooling water systems, RO water systems, paper pulp process water systems, scrubber water systems, etc. In this embodiment, the corrosion prevention effect is sufficiently exhibited as long as the water quality of a general water system (preferably a cooling water system) is suitable.

[0093] The acid consumption (pH 8.3) is not particularly limited as a condition for the water quality of the water system. From the viewpoint of a better corrosion prevention effect, a suitable upper limit is preferably 1000 mg CaCO3 / L or less, more preferably 500 mg CaCO3 / L or less, and even more preferably 300 mg CaCO3 / L or less. A suitable lower limit is preferably 10 mg CaCO3 / L or more, more preferably 25 mg CaCO3 / L or more, even more preferably 50 mg CaCO3 / L or more, and even more preferably 50, 75, or 100 mg CaCO3 / L or more. A suitable numerical range is more preferably 25 to 500 mg CaCO3 / L, and even more preferably 100 to 300 mg CaCO3 / L. The acid consumption (pH 8.3) can be determined in accordance with JIS K0101 Industrial Water Testing Method. The acid consumption is expressed by converting the amount of alkaline components (bicarbonates, carbonates, hydroxides, etc.) contained in the water into the equivalent concentration of calcium carbonate (unit: mgCaCO3 / L).

[0094] As for the water quality conditions of the water system, calcium hardness is not particularly limited, and from the viewpoint of a better corrosion prevention effect, there is no particular limit to the preferred upper limit, but for example, it is 1000 mg CaCO3 / L or less, preferably 500 mg CaCO3 / L or less, more preferably 300 mg CaCO3 / L or less, and as a preferred lower limit, it is preferably 5 mg CaCO3 / L or more, even more 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, and as a preferred numerical range, it is preferably 25 to 300 mg CaCO3 / L. The method for determining calcium hardness can be carried out in accordance with JIS K0101 Industrial Water Testing Method.

[0095] Regarding the water quality conditions of the water system, the pH of the water system is not particularly limited, but from the viewpoint of a better corrosion prevention effect, it is preferably 6 to 11, more preferably 6.5 to 10, and even more preferably 7 to 9. Also, the water temperature of the water system is not particularly limited, but from the viewpoint of a better corrosion prevention effect, it is preferably 0 to 100°C, more preferably 5 to 80°C, and even more preferably 10 to 60°C.

[0096] In a preferred embodiment of this product, it is suitable for application to water systems where metal materials susceptible to corrosion by water are used in various locations (e.g., heat exchangers, piping, etc.), more preferably to cooling water systems, and even more preferably to circulating cooling water systems. According to this embodiment, the corrosion protection effect of the corrosion protection treatment method of the present invention is fully demonstrated through the more preferred application.

[0097] The method of this embodiment can also be implemented by a control unit including a CPU in a device (e.g., a computer, PLC, server, cloud service, etc.) for managing the metal corrosion protection treatment described above and the cooling water system described later. Alternatively, the method of this embodiment can be stored as a program in hardware resources equipped with a recording medium (non-volatile memory (USB memory, etc.), SSD, HDD, CD, DVD, Blu-ray D, etc.) and implemented by the control unit. The recording medium is preferably a computer-readable recording medium. It is also possible to provide a metal corrosion protection treatment system that controls the addition of chemicals to the water system by the control unit, or a device equipped with the control unit or such system. Furthermore, the management device may include, as computer components, at least a CPU, an input unit such as a keyboard, a communication unit such as a network, a display unit such as a display, a storage unit such as an HDD, ROM or RAM, etc., from which one or more can be selected. Of these, it is preferable to include RAM, a storage unit, a display unit and an input unit, and each selected component is connected, for example, by a bus as a data transmission path.

[0098] <Cooling water system> The cooling water system to be applied to this embodiment is not particularly limited, but a system through which cooling water is used for operating heat exchangers and the like in air conditioning equipment for buildings and community facilities, and in plants, is preferred. Furthermore, the cooling water system may be a single-pass type, an open-circulation type, or a closed-circulation type.

[0099] In this embodiment, by applying it to a circulating cooling water system, it can exhibit excellent corrosion protection in the circulating cooling water system. The circulating cooling water system is not particularly limited, and is preferably a water system that includes a cooling tower installed in, for example, an air conditioning system, a petrochemical complex, or a general factory. The circulating cooling water system is preferably configured to indirectly cool the heat sources generated in these air conditioning systems, general factories, etc., and may be a general water system configured to include a heat exchanger, a circulating water channel, and a cooling tower.

[0100] The type of circulating cooling water system is not particularly limited, but it may be either an open circulating cooling water system or a closed circulating cooling water system. The open circulating cooling water system preferably has a configuration that allows cooling water to circulate in an open manner, while the closed circulating cooling water system preferably has a configuration that allows cooling water to circulate in a closed manner.

[0101] Furthermore, the metal corrosion protection treatment method for a cooling water system of this embodiment (more specifically, the metal corrosion protection treatment method for metal members in a cooling water system) preferably includes at least a step of adding the film-forming amine, the polymer, and the phosphorus compound to the cooling water system and bringing them into contact with the metal members. In this case, the film-forming amine and the polymer, or the film-forming amine, the polymer, and the phosphorus compound may be added as a one-component metal corrosion protection agent, or as a multi-component combination product of metal corrosion protection agents. The film-forming amine, the polymer, and the phosphorus compound may be added to the cooling water system at the same time or at different times, and it is preferable to add them so that these three components are present together in the aqueous system. The period during which these three components are present together in the aqueous system is not particularly limited and 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 that order. Furthermore, after mixing these, the aforementioned polymer (second polymer) may be added. The first and second polymers may be the same or different polymers. The amount of the second polymer added is preferably 0.5 to 2 times or more the amount of the first polymer added, and more preferably about 1.5 to 2.5 times. If the first and second polymers are the same polymer, the total amount used for the first and second polymers may be used as the total amount used or total amount added. Furthermore, the location of chemical addition is not particularly limited and can be anywhere in the cooling water system, such as blowers, water sprayers, pits, makeup water supply systems, chemical injection systems, circulation channels, transfer pumps, heat exchangers, etc. Preferably, the chemicals are added at one or more locations selected from these, such as makeup water supply systems, chemical injection systems, circulation channels, and transfer pumps. By adding these three components so that they are present at any location in the water system, a better corrosion protection effect can be obtained for metal materials in contact with water downstream. Also, if all or part of the water system is circulating, the circulation of the water system will mix these three components, resulting in a better corrosion protection effect for metal materials in contact with the water in the water system.

[0102] Thus, the metal corrosion protection treatment method of this embodiment can provide excellent corrosion protection to metal components that come into contact with water.

[0103] An example of this embodiment, a method for treating metal corrosion on an open-circulating cooling water system 1, will be described with reference to Figure 1, but this embodiment is not limited to this. In the open-circulating cooling water system 1, the water containing the film-forming amine, the polymer, and the phosphorus compound is transferred from the pit 15 to the heat exchanger 30 via the circulation channel 20 by the transfer pump 21, and then returns to the open-type cooling tower 10 via the circulation channel 20 after passing through the heat exchanger 30. Within the cooling tower 10, the water containing these components is stored in the pit 15 after passing through the water spraying means 12 and the packing material area 13, and is again transferred to the circulation channel 20 by the pump 21. In this embodiment, the corrosion-preventive effect on the cooling water system can be maintained during this circulation. Through this circulation, the film-forming amine and the polymer, or the film-forming amine and the polymer and the phosphorus compound present in the water system, can come into contact with the metal member and exert a corrosion-preventive effect on the metal member. Furthermore, it is preferable to add the film-forming amine, the polymer, and the phosphorus compound to the aqueous system using a chemical injection device capable of adding each of these components individually or as a mixture of two or three components, so that these three components are present together in the aqueous system. In addition, the amount of each component added may be adjusted so that each component is within a predetermined concentration range in the aqueous system.

[0104] The film-forming amine and the polymer, or the film-forming amine and the polymer and the phosphorus compound, are transferred to the pit 15 simultaneously or separately by one or more drug injection means 17, and the two may be mixed in the piping during this transfer, or they may be mixed in the pit 15. The drug injection means 17 may consist of one or more units; for example, there may be multiple separate drug injection means for the film-forming amine, the polymer, and the phosphorus compound, or there may be one drug injection means for adding a one-component drug containing these to an aqueous system or for mixing these components. Water that is insufficient due to evaporation, etc., is supplied to the pit 15 as needed by a makeup water supply means 16, and the flow path for supplying this makeup water to the pit 15 may be configured to allow the addition of one or more drugs from the drug injection means 17. Cooling air is discharged from the outside air by the blower means 11, through louvers 18, 13, and 12, and then from 11.

[0105] In the description of the example of the aqueous metal corrosion protection treatment method according to this embodiment described above, explanations of the phosphorus compound, the film-forming amine, the polymer, their usage concentrations and ratios, and the technical features, configurations, definitions, terms, treatment methods, and various means of aqueous metal corrosion protection treatment, aqueous metal corrosion protection treatment management, aqueous metal corrosion protection system, aqueous metal corrosion protection treatment method, etc., which are the same as or overlap with the content described later (for example, "2." to "3."), will be omitted as appropriate. However, the explanations in "1." to "3.", etc., apply to any of the embodiments and can be appropriately adopted in each embodiment.

[0106] 2. Metal corrosion inhibitors, etc. according to this embodiment In describing examples of metal corrosion inhibitors, water treatment agents, water treatment agent combination products, etc., according to the present invention, explanations of the phosphorus compound, the film-forming amine, the polymer, their usage concentrations and usage ratios, and technical features, configurations, definitions, terms, treatment methods, and various means, such as those described above (e.g., "1.") and below (e.g., "3."), will be omitted as appropriate. However, explanations such as "1." to "3." apply to any of the embodiments and can be appropriately adopted in each embodiment.

[0107] By using the phosphorus compound, the film-forming amine, and the polymer in an aqueous system, a very excellent corrosion-preventive effect can be achieved. That is, the combination of the phosphorus compound, the film-forming amine, and the polymer can be included as an active ingredient in aqueous corrosion-preventive compositions, aqueous metal corrosion inhibitors, water treatment agents, chemicals, etc., or can be used in such compositions, etc. In this embodiment, the composition may be an agent, or the agent may be a composition. Furthermore, in this embodiment, it is preferable that the phosphorus compound, the film-forming amine, and the polymer used are configured such that the amount added to the aqueous system is greater than or equal to a predetermined amount, or that they are used in such a way that the amount added to the aqueous system is greater than or equal to a predetermined amount. Furthermore, the phosphorus compound, the film-forming amine, and the polymer or mixture thereof can be used to produce the water-based metal corrosion inhibitor of this embodiment. Furthermore, this embodiment may also provide the use of the phosphorus compound, the film-forming amine, and the polymer or a mixture thereof for water-based metal corrosion protection and the like. This embodiment also provides a water-based metal corrosion prevention method or water-based metal corrosion prevention treatment method using the phosphorus compound, the film-forming amine, and the polymer or a mixture thereof, or a water-based metal corrosion inhibitor, water treatment agent, water treatment agent combination product, etc.

[0108] Furthermore, as another aspect of this embodiment, a metal corrosion inhibitor comprising a phosphorus compound, a film-forming amine, and a polymer can be provided.

[0109] Furthermore, as another aspect of this embodiment, it is also possible to provide phosphorus compounds, film-forming amines, and polymers or their use, or compositions containing these three components or their use, for use in metal corrosion protection or as metal corrosion inhibitors.

[0110] Another aspect of this embodiment is the provision of phosphorus compounds, film-forming amines, and polymers or their uses, or compositions containing these three components or their uses, for manufacturing or using metal corrosion inhibitors.

[0111] Another aspect of this embodiment is a water treatment agent containing at least one of a phosphorus compound, a film-forming amine, or a polymer. When used for water-based metal corrosion protection, a water treatment agent for metal corrosion protection can also be provided, which is used in combination with a phosphorus compound, a film-forming amine, and a polymer in the water system. This water treatment agent may also be a combination product for water treatment agents, consisting of at least one, two, or three selected from a first water treatment agent containing the phosphorus compound, a second water treatment agent containing the film-forming amine, and a third water treatment agent containing the polymer.

[0112] Another aspect of this embodiment is a water treatment agent containing a film-forming amine and / or a polymer. It is also possible to provide a water treatment agent that, when used in an aqueous system, is used in combination with the film-forming amine and the polymer to enhance metal corrosion protection by phosphorus compounds.

[0113] Another aspect of this embodiment may also be provided of phosphorus compounds, film-forming amines, and polymers or uses thereof for manufacturing or using the aforementioned agent.

[0114] Furthermore, as another aspect of this embodiment, it is also possible to provide a water-based corrosion prevention method for suppressing the corrosion of metals that come into contact with water, using the aforementioned agent.

[0115] The polymer is preferably a low molecular weight polymer, and more preferably a low molecular weight polymer with a weight-average molecular weight of 500 to 100,000. The polymer is also 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 even more 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. Furthermore, it is preferable that the polymer is included in the composition or used in such a way that it is added to the aqueous system at an amount of 6 mg / L or more.

[0116] The polymer is preferably a (meth)acrylic acid-based polymer containing a sulfonic acid group, and the molar ratio of the (meth)acrylic acid monomer to the sulfonic acid monomer in the polymer is preferably 60-95:40-5. Among the (meth)acrylic acid-based polymers, AA / AMPS polymers and / or AA / HAPS polymers are preferred.

[0117] The phosphorus compound is preferably a phosphonic acid compound. The film-forming amine is preferably a long-chain aliphatic amine compound, of which a long-chain aliphatic diamine compound is preferred.

[0118] The ratio of the film-forming amine and the polymer used in the aqueous system or the blending ratio in the drug is preferably 5-70:3-30. Furthermore, the ratio of phosphorus compounds and the film-forming amines used in the aqueous system or their blending ratio in the drug is preferably 0.1 to 10 parts phosphorus compounds to 5 to 70 parts film-forming amines.

[0119] Furthermore, the ratio of phosphorus compounds and polymers used in the aqueous system or the blending ratio in the drug is preferably 0.1 to 10 parts phosphorus compounds to 3 to 30 parts polymers or 6 to 30 parts polymers.

[0120] Furthermore, the ratio of phosphorus compound, the film-forming amine, and the polymer used, or the blending ratio in the drug, is preferably 0.1-10 parts phosphorus compound, 5-70 parts film-forming amine, and 3-30 parts polymer or 6-30 parts polymer.

[0121] 3. This technology may also employ the following technical features, configurations, or other aspects: · [1] This is a water-based corrosion prevention method for suppressing the corrosion of metals in contact with water. A water-based corrosion prevention method comprising: a phosphorus compound; a film-forming amine; and a copolymer of (meth)acrylic acid monomer and sulfonic acid group-containing monomer. The molecular weight of the copolymer is preferably 500 to 100,000 (weight average molecular weight). The monomer ratio of (meth)acrylic acid monomer to sulfonic acid group-containing monomer in the copolymer is preferably 60 to 95:40 to 5. Preferably, the amount of the copolymer of (meth)acrylic acid monomer and sulfonic acid group-containing monomer used is greater than 5 mg / L. • [2] The method according to [1], wherein the copolymer is a copolymer obtained from (a) a (meth)acrylic acid monomer and (b) (i) an amide group and sulfonic acid group-containing monomer and / or (ii) a hydroxyl group and sulfonic acid group-containing monomer. The monomer ratio of the (meth)acrylic acid monomer to the amide group and sulfonic acid group-containing monomer in the copolymer is preferably 60-95:40-5. • [3] The method according to [1] or [2], 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, and more preferably an aliphatic diamine compound. • [4] The method according to any one of [1] to [3] above, wherein the phosphorus compound is a phosphate compound and / or a phosphonic acid compound, and more preferably a phosphonic acid compound. A mixture of the phosphorus compound and a corrosion inhibitor other than the phosphorus compound (for example, a zinc salt and / or a copper corrosion inhibitor) may be used. • [5] The method according to any one of [1] to [4], wherein when using a film-forming amine in the aqueous system, a copolymer of the (meth)acrylic acid monomer and a sulfonic acid group-containing monomer is used in combination. • [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.

[0122] • [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, and more preferably a low molecular weight polymer with a weight-average molecular weight of 500 to 100,000. The polymer is preferably a water-soluble organic polymer, and more preferably a copolymer of a (meth)acrylic acid monomer and a sulfonic acid group-containing monomer. The polymer is preferably the copolymer described in any one of [1] to [6] above. The phosphorus compound and / or the film-forming amine is preferably the compound described in [3] and / or [4] above. The metal corrosion inhibitor is preferably configured so that the polymer can be added in an amount greater than 5 mg / L, or the metal corrosion inhibitor is preferably used so that the polymer is added in an amount greater than 5 mg / L. • [8] A phosphorus compound, a film-forming amine, and a polymer or the use thereof, or a composition containing these three components or the use thereof, for use in metal corrosion protection or as a metal corrosion inhibitor. The polymer is preferably the polymer described in [7] above or the copolymer described in any one of [1] to [6] above. The phosphorus compound and / or the film-forming amine is preferably the compound described in [3] and / or [4] above. The polymer is preferably used in a solution of water at a concentration of more than 5 mg / L, or the composition is preferably configured to be used with a polymer addition amount of more than 5 mg / L. • [9] The use of a phosphorus compound, a film-forming amine, and a polymer, or one, two, or three of these, or a composition containing these three components, or the use thereof, in the manufacture of metal corrosion inhibitors, etc. The polymer is preferably the polymer described in [7] above or the copolymer described in any one of [1] to [6] above. The phosphorus compound and / or the film-forming amine is preferably the compound described in [3] and / or [4] above. The polymer is preferably used in an aqueous system in a concentration of more than 5 mg / L, or the composition is preferably configured to be usable with a polymer addition amount of more than 5 mg / L.

[0123] ·

[10] A water treatment agent containing at least one of a phosphorus compound, a film-forming amine, or a polymer, which is used for water-based metal corrosion prevention, and is used in combination with or for use with a water system containing a phosphorus compound, a film-forming amine, and a polymer. The water treatment agent may also be a combination product of at least one, two, or three water treatment agents selected from a first water treatment agent containing the phosphorus compound, a second water treatment agent containing the film-forming amine, and a third water treatment agent containing the polymer. The polymer is preferably the polymer described in [7] above or the copolymer described in any one of [1] to [6] above. The phosphorus compound and / or the film-forming amine is preferably the compound described in [3] and / or [4] above. The polymer is preferably used in a concentration of more than 5 mg / L in the water system, or the water treatment agent is preferably configured to be used with a polymer addition amount of more than 5 mg / L.

[0124]

[11] A water treatment agent containing a film-forming amine and / or a polymer, A water treatment agent used in water systems to enhance metal corrosion protection by phosphorus compounds by using the film-forming amine and the polymer in combination. The polymer is preferably the polymer described in [7] or the copolymer described in any one of [1] to [6]. The phosphorus compound and / or the film-forming amine are preferably the compounds described in [3] and / or [4].

[0125] ·

[12] Phosphorus compounds, film-forming amines, and polymers or uses thereof for manufacturing, manufacturing, or using any one of the agents described in [7] to

[11] above. ·

[13] A water-based corrosion prevention method for suppressing the corrosion of metals in contact with water, a method for strengthening metal corrosion prevention by phosphorus compounds, or a method for reducing the amount of phosphorus used in a water system, using the components or agents described in [7] to

[12] above. [Examples]

[0126] The embodiments of the present invention will be described with reference to the following examples and comparative examples. The examples described below are merely representative examples of the present invention and should not be interpreted as narrowing the scope of the invention.

[0127] [Test Example 1] <Experimental conditions> Pure water was placed in a 1L glass beaker, and sodium bicarbonate solution and calcium chloride solution were added to adjust the pH to 8.4, acid consumption to 150 mg CaCO3 / L, and calcium hardness to 150 mg CaCO3 / L. As a corrosion inhibitor, 4 mg of HEDP (hydroxyethylidene diphosphonic acid) was added at PO4 / L, and as a scale inhibitor, 5 mg of AA / AMPS polymer (monomer ratio (mol% ratio) 80:20, average weight molecular weight 20,000) was added at solid / L. After adding 50 mg of film-forming amine (alkylpropanediamine (alkyl with 16-18 carbon atoms)), 10 mg of various polymers were added at solid / L.

[0128] Tables 1-3 show test examples 1 (Reference Examples 1-1 to 1-6 and Examples 1-7 to 1-10), 2 (Reference Example 2-1 and Examples 2-2 to 2-4), and 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 polymers. For reference, we also conducted tests without adding HEDP and without adding film-forming amines. As shown in Tables 1 and 2, the polymers used were AA / AMPS polymers, AA / HAPS polymers, and polymaleic acid polymers, with an average weight molecular weight of 400 to 110,000. The molecular weight of the polymers is the average weight molecular weight and was determined by GPC analysis (standard material: PAANA, manufactured by PSS: sodium polyacrylate).

[0129] <Corrosion rate test (mg / dm 2 / day)> The test specimen 101 was made of SPCC (15 mm x 30 mm) and immersed in test water 102. The test was conducted using a rotary corrosion test apparatus 100 (Figure 2) equipped with a stirring device 103 for agitating the test water with a stirrer and a temperature control device 104 for heating and cooling the test water 102. The test was performed at a water temperature of 40°C for 3 days at 150 rpm. The SPCC (Steel Plate Cold Commercial: a type of cold-rolled steel sheet) is a low-carbon steel with a carbon content of 0.15% or less. After the test was completed, the test specimens were removed, derubbed with hydrochloric acid, and then the corrosion weight was measured. Based on the corrosion weight, the corrosion rate (mg / dm²) was calculated. 2 I calculated ( / day). In addition, to verify the effects of different corrosion inhibitors used, we also conducted evaluations using PBTC (4 mg PO4 / L) instead of HEDP (4 mg PO4 / L).

[0130] [Table 1]

[0131] [Table 2]

[0132] [Table 3]

[0133] <Results / Discussion> Tables 1 and 2 show the results when HEDP was used as a corrosion inhibitor, and Table 3 shows the results when PBTC was used. Regardless of the type of corrosion inhibitor, it was confirmed that using AA / AMPS or AA / HAPS with a molecular weight of 4,000 to 20,000 significantly increased the corrosion inhibitory effect and extended the lifespan of the metal during the addition of film-forming amines. Furthermore, considering the corrosion rate trends, the AA / AMPS ratio and AA / HAPS ratio (mol%) of AA / AMPS polymers and AA / HAPS polymers are considered to be preferably 1 to 95:99 to 5, more preferably 60 to 95:40 to 5, and more preferably 75 to 90:25 to 10. This confirmed that the corrosion prevention effect on metal materials in contact with water is significantly enhanced by the presence of three components—a film-forming amine, a (meth)acrylic acid-based polymer containing low molecular weight sulfur atoms, and a phosphonic acid compound—in an aqueous system. Furthermore, a synergistic effect on the corrosion inhibition of metal materials in contact with water was confirmed by using the film-forming amine and the (meth)acrylic acid-based polymer containing low molecular weight sulfur atoms in combination. It is also preferable to use the polymer in an aqueous system at a concentration of more than 5 mg / L.

[0134] In this specification, numbers, letters, etc., such as "first, second, third...", "A, B, C...", and "primary, secondary, tertiary...", may be used for convenience in explanations, but this does not mean that the present invention will be narrowly limited in meaning by order, and the order may be changed at will. Combination products may be used in combination. Also, in this specification, "to do" such as "to manage" may be replaced with "method," "process," "means," or "step," and these terms may be replaced as appropriate. For example, "step" may be replaced with "to do," "method," "process," or "means," and "means" may be replaced with "to do," "method," "process," or "step." Furthermore, in this specification, "system" may also mean a mechanism, apparatus, means, or part; "mechanism" may also mean a system, apparatus, means, or part; "apparatus" may also mean a system, mechanism, means, or part; "means" may also mean a mechanism, system, apparatus, or part; and "part" may mean a mechanism, means, apparatus, or system, or a mechanism, means, or apparatus for providing these. [Explanation of symbols]

[0135] 1 Open circulating cooling water system, 10 Open-type cooling tower, 11 Air blower, 12 Water spraying means, 13 Packing material area, 14 Space, 15 Pit, 16 Makeup water supply means, 17 Chemical injection means, 18 Louver, 20 Circulation channel, 21 Transfer pump, 30 Heat exchanger

Claims

1. This is a water-based corrosion prevention method for suppressing the corrosion of metals in contact with water. The aqueous system used contains a phosphorus compound, a film-forming amine, and a copolymer of a (meth)acrylic acid monomer and a sulfonic acid group-containing monomer with a weight-average molecular weight of 500 to 100,000 determined by GPC analysis, at a concentration of more than 5 mg / L. The phosphorus compound is a phosphonic acid compound, The film-forming amine is a long-chain aliphatic amine compound, which has a long-chain aliphatic group, and the long-chain aliphatic group is a long-chain alkyl group, and the number of carbon atoms of the long-chain alkyl group is 10 to 22. A method for preventing corrosion in the aforementioned water system.

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

3. The method according to claim 1 or 2, wherein the copolymer has a molar ratio of acrylic acid monomer to sulfonic acid group-containing monomer of 60 to 95:40 to 5.

4. The method according to claim 1 or 2, wherein the sulfonic acid group-containing monomer in the copolymer is 2-acrylamido-2-methylpropanesulfonic acid and / or 3-alyloxy-2-hydroxypropanesulfonic acid.

5. The method according to claim 1 or 2, wherein the long-chain aliphatic amine compound is a long-chain aliphatic diamine compound.

6. The method according to claim 1 or 2, wherein the long-chain aliphatic amine compound is an alkylpropanediamine.

7. The method according to claim 1 or 2, wherein the phosphonic acid compound is 2-phosphonobutane-1,2,4-tricarboxylic acid and / or 1-hydroxyethylidene-1,1-diphosphonic acid.

8. The method according to claim 1 or 2, wherein when using the long-chain aliphatic amine compound in the aqueous system, a copolymer of the (meth)acrylic acid monomer and the sulfo group-containing monomer is used in combination.

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

10. The material 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 determined by GPC analysis, wherein the phosphorus compound is a phosphonic acid compound. The film-forming amine is a long-chain aliphatic amine compound, the long-chain aliphatic amine compound has a long-chain aliphatic group, the long-chain aliphatic group is a long-chain alkyl group, and the number of carbon atoms of the long-chain alkyl group is 10 to 22. The polymer is a copolymer of a (meth)acrylic acid monomer and a sulfonic acid group-containing monomer. Yes, the polymer in question is included as a metal corrosion inhibitor to be used in amounts exceeding 5 mg / L.

11. A water treatment agent containing at least one of a phosphorus compound, a film-forming amine, or a copolymer of a (meth)acrylic acid monomer with a weight-average molecular weight of 500 to 100,000 and a sulfonic acid group-containing monomer. When used in water-based metal corrosion protection, the phosphorus compound, the film-forming amine, and the copolymer of the (meth)acrylic acid monomer and the sulfonic acid group-containing monomer are used in combination with the water-based solution. The copolymer is included to be used in an amount greater than 5 mg / L. The phosphorus compound is a phosphonic acid compound, The film-forming amine is a long-chain aliphatic amine compound, which has a long-chain aliphatic group, and the long-chain aliphatic group is a long-chain alkyl group, and the number of carbon atoms of the long-chain alkyl group is 10 to 22. Water treatment agent for metal corrosion prevention.

12. A water treatment agent containing a film-forming amine and / or a copolymer of a (meth)acrylic acid monomer with a weight-average molecular weight of 500 to 100,000 and a sulfonic acid group-containing monomer, When used in aqueous systems, the film-forming amine and the copolymer of the (meth)acrylic acid monomer and the sulfonic acid group-containing monomer are used in combination to enhance metal corrosion protection by phosphorus compounds. The copolymer is included to be used in an amount greater than 5 mg / L. The phosphorus compound is a phosphonic acid compound, The film-forming amine is a long-chain aliphatic amine compound, which has a long-chain aliphatic group, and the long-chain aliphatic group is a long-chain alkyl group, and the number of carbon atoms of the long-chain alkyl group is 10 to 22. Water treatment agent.

13. A water-based corrosion prevention method for suppressing the corrosion of metals in contact with water, using the agent described in claim 10, 11, or 12.

Images