JP2011045861A - Water treatment agent and water treatment method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a corrosion inhibitor and a corrosion inhibiting method which contain no environmental contaminants, such as heavy metals and phosphorus, or are excellent in a metal corrosion inhibiting effect even when used in a very low concentration, thereby effectively performing corrosion inhibition while inhibiting scale adhesion to the metal surface in a water system. <P>SOLUTION: A water treatment agent includes, as an active ingredient, a copolymer containing (1) itaconic acid and (2) maleic acid and/or fumaric acid as active ingredients, wherein the mixing weight ratio of (1) to (2) is from 10-90:90-10, and the total of (1) and (2) is equal to or more than 80 wt.% in the monomer composition of the copolymer, and a water treatment method adds the copolymer to a target water system. A water treatment agent contains, as active ingredients, the copolymer and a polymer containing a sulfonic group, and a water treatment method adds the copolymer and the polymer containing a sulfonic group to a target water system. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention effectively suppresses scale adhesion and corrosion suppression on the surface of metal materials in contact with water in various water systems such as industrial water systems, cooling water systems, hot water systems, boiler water systems, cleaning water, process water systems, and drainage systems. The present invention relates to a water treatment agent and a water treatment method.

  In various water systems such as a cooling water system, a hot water system, a boiler water system, a washing water, and a process water system, the metal material in contact with water is likely to be corroded or scaled. Therefore, conventionally, heavy metals such as chromate, zinc salt, molybdate, and various phosphorus compounds have been used as corrosion inhibitors and scale inhibitors. However, due to the recent emphasis on environmental issues, such as the release of highly toxic heavy metals such as chromate and zinc into the environment, eutrophication of lakes by phosphorus and the occurrence of red tides in closed waters, these compounds and Wastewater concentration regulations for heavy metals have been strengthened, and the trend is toward reducing emissions. Therefore, various methods using carboxylic acid polymers have been proposed as environmentally friendly treatment agents that replace conventional products.

  For example, a method using a 100: 40 to 100: 1 (molar ratio) copolymer hydrolyzate of a monoethylenically unsaturated monomer such as (meth) acrylic acid and its ester and maleic anhydride (see Patent Document 1) ), A method using a terpolymer of 30 to 80% by weight of maleic anhydride, 10 to 40% by weight of ethyl acrylate and 10 to 30% by weight of styrene or 1-decene (see Patent Document 2), maleic acid and isobutylene And the Langerian index is 1. Corrosion control method (see Patent Document 3) that manages 5 or more and the product of silica concentration and Ca hardness is 2000 or more, co-weight of 80 to 90 mol% maleic anhydride and 10 to 20 mol% olefin having 5 to 12 carbon atoms A method for inhibiting metal corrosion using a combined hydrolyzate (see Patent Document 4) is disclosed. However, in consideration of the influence on the surrounding environment, no method has yet been obtained that does not contain heavy metals and phosphorus and exhibits a satisfactory metal corrosion inhibition effect and scale inhibition effect.

Japanese Patent Publication No.54-29998 Japanese Patent No. 2942991 Japanese Patent Publication No. 4-33868 Japanese Patent Publication No. 5-81320

  The problem of the present invention is that it does not contain any environmental pollutants such as heavy metals and phosphorus, or has an excellent corrosion inhibition effect on metals that come into contact with water even when used at a very low concentration. An object of the present invention is to provide a water treatment agent and a water treatment method capable of effectively suppressing corrosion while suppressing.

  The present inventor makes full use of the polymer synthesis technology and the corrosion inhibition effect of metal in contact with water and the evaluation technology of the scale inhibition effect to determine the relationship between the polymer composition and the corrosion inhibition effect and scale inhibition effect of the metal in contact with water. As a result of intensive studies, a specific copolymer containing itaconic acid is significantly more effective in preventing scale than homopolymers such as itaconic acid homopolymers, maleic acid homopolymers, and fumaric acid homopolymers. The inventors have found that a corrosion inhibiting effect is exhibited, and have completed the present invention.

  That is, the invention according to claim 1 is a copolymer containing (1) itaconic acid and (2) maleic acid and / or fumaric acid as active ingredients, wherein the blending weight ratio of (1) and (2) is 10 to 90: 90 to 10 and a water treatment agent comprising, as an active ingredient, a copolymer in which the sum of (1) and (2) is 80% by weight or more of the monomer composition of the copolymer It is.

  The invention according to claim 2 is a copolymer comprising (1) itaconic acid and (2) maleic acid and / or fumaric acid as active ingredients, wherein the blending weight ratio of (1) and (2) is 10 to 10. 90: 90-10, and a water treatment method characterized by adding a copolymer in which the sum of (1) and (2) is 80% by weight or more of the monomer composition of the copolymer to the target aqueous system. is there.

  The invention according to claim 3 is a copolymer comprising (1) itaconic acid and (2) maleic acid and / or fumaric acid as active ingredients, wherein the blending weight ratio of (1) and (2) is 10 to 10. 90: 90-10, and a copolymer having a total of (1) and (2) of 80% by weight or more of the monomer composition of the copolymer and a sulfonic acid group-containing polymer as an active ingredient It is a water treatment agent.

  The invention according to claim 4 is a copolymer comprising (1) itaconic acid and (2) maleic acid and / or fumaric acid as active ingredients, wherein the blending weight ratio of (1) and (2) is 10 to 10. 90: 90-10, and adding the sulfonic acid group-containing polymer to the target aqueous system together with the copolymer in which the sum of (1) and (2) is 80% by weight or more of the monomer composition of the copolymer. It is the water treatment method characterized.

  Since the water treatment agent and water treatment method of the present invention have an effect equal to or higher than the corrosion inhibition effect of conventional water treatment agents using heavy metals and phosphorus, environmental pollutants such as heavy metals and phosphorus are removed. It can be used at a very low concentration, or it can be used at a very low concentration, has no impact on the environment, and also has a scale control effect, which can greatly contribute to stable operation of the factory, reduction of maintenance costs for equipment and facilities, and safe operation.

It is a systematic diagram which shows the test apparatus used for the Example.

Hereinafter, embodiments of the present invention will be described in detail.
The water treatment agent of the present invention is a copolymer containing (1) itaconic acid and (2) maleic acid and / or fumaric acid as active ingredients, wherein the blending weight ratio of (1) and (2) is 10 to 10. 90:90 to 10 and a copolymer in which the total of (1) and (2) is 80% by weight or more of the monomer composition of the copolymer is included as an active ingredient.

  The copolymer used in the present invention is produced by copolymerizing an itaconic acid monomer with a maleic acid monomer and / or a fumaric acid monomer. Examples of the itaconic acid monomer include itaconic acid and neutralized salts thereof, itaconic anhydride and a mixture thereof. Examples of the neutralized salt include alkali metal salts (specifically, potassium salts, sodium salts, etc.) and ammonium salts, and one or more of these may be used. Examples of maleic monomers include maleic acid and neutralized salts thereof, maleic anhydride, and mixtures thereof. The neutralized salt is the same as that exemplified for the itaconic acid monomer. Examples of the fumaric acid monomer include fumaric acid and neutralized salts thereof, and the neutralized salt is the same as that exemplified for the itaconic acid monomer.

  The monomer composition in the copolymer used in the present invention is 10 to 90% by weight of itaconic acid, preferably 40 to 80% by weight. The total amount of maleic acid and fumaric acid is 90 to 10% by weight, preferably 60 to 20% by weight.

  The copolymer used in the present invention may contain other monomers other than itaconic acid, maleic acid and fumaric acid as long as the effects of the present invention are not impaired. % By weight or less.

  Examples of the other monomers include unsaturated carboxylic acids such as acrylic acid, methacrylic acid and crotonic acid; (meth) acrylic acid alkyl esters; (meth) acrylic acid hydroxyl alkyl esters; (meth) acrylamide; N- Alkyl substituted (meth) acrylamides; olefins such as ethylene, propylene, isopropylene, butylene, isobutylene, hexene, 2-ethylhexene, pentene, isopentene, octene, isooctene; vinyl alkyl methyl ethers, etc. Two or more kinds may be used.

  The molecular weight of the copolymer used in the present invention is usually 300 to 3000, preferably 400 to 2000. If the molecular weight is out of this range, the corrosion inhibiting effect and the scale inhibiting effect are reduced, which is not preferable. The copolymer may be a block or random copolymer.

  The method for producing the copolymer used in the present invention is not particularly limited, and a method generally used as a polymerization method of these unsaturated carboxylic acids, that is, unsaturated carboxylic acids as monomers in an aqueous solution or xylene, In an organic solvent such as toluene or isopropyl alcohol, in the presence of a polymerization initiator such as hydrogen peroxide, benzoyl peroxide, persulfate, or di-t-butyl peroxide, add a polymerization regulator as necessary and heat. It is manufactured by doing.

  Adjustment of the molecular weight of the copolymer used in the present invention can be achieved by appropriately changing the amount of polymerization initiator, polymerization temperature, polymerization time, monomer concentration, type and concentration of polymerization regulator, and the like. The temperature of the polymerization reaction varies depending on the type of polymerization initiator, the type of solvent, and the like, but is usually controlled to a reflux temperature or a temperature lower than the reflux temperature, and is usually in the range of 40 to 200 ° C. The polymerization initiator is preferably added dropwise sequentially over about 15 minutes to 6 hours, rather than being added all at once at the start of the polymerization reaction.

  When the solvent used in the production of the copolymer used in the present invention is a non-aqueous solvent such as toluene or xylene, itaconic acid esters, itaconic anhydride, maleic acid instead of itaconic acid, maleic anhydride or maleic acid ester instead of itaconic acid In place of fumaric acid, a monomer that is soluble in a non-aqueous solvent such as fumaric acid ester is used, and a polymerization initiator that is soluble in a non-aqueous solvent such as benzoyl peroxide or di-t-butyl peroxide is used. . After producing a copolymer containing an anhydride or ester, the solvent is removed by decantation or evaporation, and the desired water-soluble copolymer is obtained by hydrolyzing the ester or anhydride while heating by adding water. Obtainable. However, since polymerization in a non-aqueous solvent requires a solvent removal step and hydrolysis step, not only is the operation complicated, but the heating energy cost and solvent cost used in these steps are large, Not economical. In addition, when harmful organic solvents are released into the atmosphere, waste water, soil, etc., the impact on the environment of the human body cannot be ignored.

  For this reason, in the manufacturing method of the copolymer used by this invention, it is preferable to manufacture by the water-system polymerization method which does not require a solvent removal process and a hydrolysis process. In the case of an aqueous polymerization method using mainly water as a solvent, it is possible to use a monomer soluble in water such as itaconic acid, itaconic anhydride, maleic acid, maleic anhydride, fumaric acid, hydrogen peroxide, persulfate It is produced using a polymerization initiator that is soluble in water, such as a water-soluble azo catalyst. However, in this state, the polymerization reaction rate cannot be sufficiently increased, and a considerable amount of unreacted itaconic acid, maleic acid and / or fumaric acid remains, so that sufficient corrosion inhibition effect and scale inhibition effect are obtained. It is difficult.

  Therefore, in order to synthesize the copolymer with high yield by an aqueous polymerization method, at the time of polymerization of the copolymer, monomers such as itaconic acid, maleic acid and / or fumaric acid, sodium hydroxide, potassium hydroxide, etc. It is preferable to add an alkali metal hydroxide. The amount of the alkali metal hydroxide used here is such that the alkali metal hydroxide is added in a molar ratio of 0.2 to 2 with respect to the total number of unsaturated carboxylic acids such as maleic acid and fumaric acid. Is preferred. The alkali metal hydroxide is added all at once before the start of polymerization, or is added sequentially or all at once with the polymerization initiator in the polymerization reaction stage.

  In the production of a copolymer by an aqueous polymerization method, the amount of the monomer blended with respect to the total production charge is not particularly limited, but is usually in the range of 10 to 60% by weight. In addition, as the addition timing of the monomer, itaconic acid may be added together with water before the start of polymerization, or may be added sequentially or batchwise in the polymerization reaction stage, but maleic acid, maleic anhydride, fumaric acid It is preferable to add all together with water before the start of polymerization.

  As the polymerization initiator in the aqueous polymerization method, it is preferable to use hydrogen peroxide and persulfate together, rather than using either hydrogen peroxide or persulfate alone. The amount of the polymerization initiator is 0.5 to 20% by weight of hydrogen peroxide and 0.1 to 5% of persulfate with respect to the amount charged for production in order to synthesize a copolymer by an aqueous polymerization method with high yield. The range of weight is preferable, and the polymerization reaction temperature is preferably in the range of 60 to 120 ° C.

  Further, in the aqueous polymerization, it is preferable to add a redox catalyst together with the polymerization initiator. Preferred redox catalysts are reducible cations, including metal ions obtained from iron, zinc, cobalt, molybdenum, chromium, nickel, vanadium and cesium and combinations thereof. Preferred metal ions are ferrous ammonium sulfate, ferrous sulfate, ferrous chloride, cobalt salts (eg, cobalt sulfate hexahydrate), vanadium salts and combinations thereof. The amount of the redox catalyst is preferably in the range of 0.001 to 0.1% by weight in terms of metal with respect to the production charge.

  If any of the amount of the alkali metal hydroxide, the amount of the polymerization initiator, or the amount of the metal catalyst is out of the above range, the monomer reaction rate is not sufficiently increased, and a considerable amount of unreacted monomer remains. Therefore, it is difficult to obtain a sufficient corrosion inhibiting effect and scale inhibiting effect.

  Furthermore, secondary alcohols such as isopropyl alcohol and 2-butyl alcohol, bisulfites, sulfites and the like may be added as a polymerization regulator for aqueous polymerization.

  When the copolymer used in the present invention is produced by an aqueous polymerization method, it is preferable to add an antifoaming agent because foaming is likely to occur if the ratio of itaconic acid in the copolymer is high. The antifoaming agent used here is a polyethylene glycol type nonionic surfactant having a cloud point of 20 ° C. or higher, such as polyoxyethylene polyoxypropylene glycol, higher alcohol ethylene oxide adduct, higher alcohol ethylene oxide / propylene oxide adduct, This is preferable because separation in an aqueous solution does not occur at room temperature.

  The sulfonic acid group-containing polymer used in the present invention is a polymer containing monoethylenically unsaturated sulfonic acid, preferably a copolymer of monoethylenically unsaturated sulfonic acid and monoethylenically unsaturated carboxylic acid, A copolymer of an ethylenically unsaturated sulfonic acid, a monoethylenically unsaturated carboxylic acid and another copolymerizable monoethylenically unsaturated monomer, wherein the monomer composition in the copolymer is monoethylenic 10 to 90% by weight of unsaturated sulfonic acid, preferably 30 to 70% by weight, and the total amount of monoethylenically unsaturated carboxylic acid and other copolymerizable monoethylenically unsaturated monomers Is 10 to 90% by weight, preferably 30 to 70% by weight.

  Examples of the monoethylenically unsaturated sulfonic acid include 2-acrylamido-2-methylpropanesulfonic acid, 3-allyloxy-2-hydroxy-1-propanesulfonic acid, conjugated diene sulfonated products such as butadienesulfonic acid and isoprenesulfonic acid. One or more of styrene sulfonic acid, sulfoalkyl (meth) acrylate ester, sulfoalkyl (meth) allyl ether, sulfopheno (meth) allyl ether, (meth) allyl sulfonic acid and the like are used.

  As the monoethylenically unsaturated carboxylic acid, one or more of acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride and the like can be used. Ethylenically unsaturated monomers include (meth) acrylic acid esters (meth) acrylic acid alkyl esters, (meth) acrylic acid hydroxyl alkyl esters; (meth) acrylamides (meth) acrylamides, N-alkyl substituted (Meth) acrylamide; ethylene, propylene, isopropylene, butylene, isobutylene, hexene, 2-ethylhexene, pentene, isopentene, octene, isooctene, etc. of olefins having 2 to 8 carbon atoms; vinyl methyl ether of vinyl alkyl ether, vinyl ethyl Ether; maleic acid Alkyl ester, and the like, that one or more may be used.

  The sulfonic acid group-containing polymer used in the present invention is preferably a copolymer of 2-acrylamido-2-methylpropanesulfonic acid and (meth) acrylic acid, 3-allyloxy-2-hydroxy-1-propanesulfonic acid and (meta ) A copolymer of acrylic acid, a conjugated diene sulfonated product and a copolymer of (meth) acrylic acid. The molecular weight of the sulfonic acid group-containing polymer is usually 1,000 to 100,000, preferably 4,000 to 20,000 as a weight average molecular weight.

  The water treatment agent of the present invention is a copolymer containing (1) itaconic acid and (2) maleic acid and / or fumaric acid as active ingredients, wherein the blending weight ratio of (1) and (2) is 10 to 10. 90: 90-10, and the total content of (1) and (2) is a copolymer containing 80% by weight or more of the monomer composition of the copolymer as an active ingredient. Use an aqueous solution of the water-soluble copolymer prepared by hydrolysis of the copolymer obtained after polymerization using a non-aqueous solvent, or an aqueous solution of the water-soluble copolymer obtained by an aqueous polymerization method. be able to. Furthermore, if necessary for handling, the aqueous copolymer solution may be diluted with water to prepare a water treatment agent. Further, the water treatment agent according to the present invention comprising a sulfonic acid group-containing polymer together with the copolymer as an active ingredient is obtained by stirring and mixing the aqueous copolymer solution and the aqueous sulfonic acid group-containing polymer solution at room temperature. The mixing order of the two is not particularly limited. The blending weight ratio of the copolymer: sulfonic acid group-containing polymer in this water treatment agent is in the range of 90:10 to 10:90, preferably 70:30 to 30:70. In addition, the water treatment agent thus prepared can be diluted with water as needed for handling, or a water treatment agent in a diluted form is prepared by adding water during preparation of the water treatment agent. You can also.

  In the water treatment method of the present invention, the method of adding the water treatment agent of the present invention to the target water system, the method of adding the copolymer used in the present invention to the target water system, and the copolymer and sulfonic acid group containing in the present invention There is a method of adding the polymer separately to the target aqueous system, and the addition weight ratio when the copolymer and the sulfonic acid group-containing polymer are separately added is (the copolymer) :( sulfonic acid group-containing polymer) is 90. : 10 to 10:90, but preferably 70:30 to 30:70.

  The amount of the water treatment agent of the present invention to be added to the target water system varies depending on the target water system conditions, particularly water quality, temperature, etc., but is generally 1 to 1, as the active ingredient concentration of the blended copolymer. 000 mg / L, preferably 5 to 500 mg / L, more preferably 10 to 100 mg / L, and addition of a sulfonic acid group-containing polymer in a water treatment agent containing a copolymer and a sulfonic acid group-containing polymer as active ingredients The amount is generally from 1 to 1,000 mg / L, preferably from 5 to 500 mg / L, preferably from 10 to 100 mg / L, as the active ingredient concentration of the blended sulfonic acid group-containing polymer.

  In addition, when the copolymer and the sulfonic acid group-containing polymer used in the present invention are separately added to the target aqueous system, the amount of each addition varies depending on the target aqueous system conditions, particularly the water quality, temperature, etc. The effective concentration of the copolymer and the sulfonic acid group-containing polymer is 1 to 1,000 mg / L, preferably 5 to 500 mg / L, more preferably 10 to 100 mg / L.

  In the addition of the water treatment agent of the present invention to the target aqueous system, the addition of the copolymer used in the present invention to the target aqueous system, or the separate addition of the copolymer and the sulfonic acid group-containing polymer to the target aqueous system, Is added to a place where the scale and corrosion of the target water system are upstream and where stirring is good. When the target water system is a circulating water system, it can be added to any place in the water system, but it is generally easy to add to a place where the circulating water tank is well stirred.

  Since the water treatment agent and the water treatment method of the present invention have the effect of preventing precipitation and adhesion to various scales such as calcium carbonate, calcium sulfate, magnesium silicate, and silica, they can be applied to water quality with severe scale properties.

  The water quality to which the water treatment agent and the water treatment method of the present invention are applied has a pH of 6 or more, preferably in the range of 8 to 9.5, and from the viewpoint of corrosion inhibition, pH, Ca hardness, M alkalinity. In addition, a scaled water quality having a high silica concentration is preferred. Here, specifically, the scaleable water quality means that the Retner index: RI is 6.0 or less, preferably 5.0 or less, and it is preferable to adjust the water quality of the aqueous system so that RI is in this range.

Here, specifically, the scaleable water quality means that the Retner index: RI is 6.0 or less, preferably 5.0 or less, and it is preferable to adjust the water quality of the aqueous system so that RI is in this range.
Here, RI is an index indicating the precipitation tendency of calcium carbonate, and is calculated by the following equation.
RI = 2 × pHs−pH
Moreover, pH is the pH of circulating water, and pHs is the saturated pH of calcium carbonate shown by Formula (1).

here,
pK2: second dissociation constant of carbonic acid pKs: solubility product of calcium carbonate pCa = -log [Ca hardness] (mg-CaCO3 / L)
pA = -log [M alkalinity] (mg-CaCO3 / L)
μ: Ionic strength, calculated by the following formula.
μ = [electric conductivity] (μS / cm) × 0.0000175

  An open circulating cooling water system has a large number of heat exchangers, and the operating conditions are constantly changing. Therefore, it is difficult to accurately grasp the temperature distribution in the system. Therefore, the temperature used for the calculation of the present invention is 40 ° C., which is a typical temperature of the outlet water of the heat exchanger in the open circulating cooling water system. The pK2 at 40 ° C. is 10.2, and the pKs is 8.5. pCa, pA, and μ can be determined by measuring the Ca hardness, M alkalinity, and electrical conductivity of the circulating water by the method described in JIS K0101 (Industrial Water Test Method) and substituting it into the above formula.

  The method of adjusting the aqueous RI is usually achieved by increasing the concentration of the aqueous system and increasing the Ca hardness and the concentration and pH of the M alkalinity component contained in the makeup water. However, when the Ca hardness or M alkalinity component concentration contained in the makeup water is sufficiently small, or when it is difficult to increase the concentration, it may be difficult to reduce the RI of the aqueous system to 6 or less. In such a case, a sufficient corrosion-inhibiting effect can be exerted by adding a small amount of zinc or an alkaline compound together with the copolymer of the present invention or the copolymer of the present invention and a sulfonic acid group-containing polymer. For example, by adding about 0.2 to 3 mg / L of a zinc compound in terms of zinc, a sufficient corrosion inhibiting effect can be exhibited even when the RI is corrosive water quality of 6 or more. Alternatively, by adding an alkaline compound so that the aqueous RI is 6 or less, or 5 or less, when the Ca hardness or M alkalinity component concentration in the makeup water is low, or when it is difficult to increase the concentration However, it can be done by adjusting the addition amount of the alkaline compound.

  Alkaline compounds used here are alkali metal hydroxides such as sodium hydroxide and potassium hydroxide; calcium oxide or calcium hydroxide; carbonates and bicarbonates of alkali metals such as sodium carbonate and potassium carbonate. .

  At the start of operation of the aqueous system, it is preferable to use the condensed phosphate together with the copolymer of the present invention or the copolymer of the present invention and a sulfonic acid group-containing polymer. The condensed phosphate is a phosphate having a condensation degree of 2 or more, but pyrophosphate (condensation degree 2), tripolyphosphate (condensation degree 3), tetrapolyphosphate (condensation degree 4), hexametaphosphate, etc. Can be used. Generally, what is marketed under the trade name of sodium hexametaphosphate is a chain condensed phosphate having an average condensation degree of 10 or more, but a more preferable condensed phosphate has an average condensation degree of 30 to 100. It is a chain condensed phosphate. The addition amount of the condensed phosphate at the start of the aqueous operation is usually 3 to 200 mg / L, preferably 5 to 100 mg / L.

The water quality of the treated water system (target water system) to which the water treatment agent and the water treatment method of the present invention are applied is not particularly limited, but is usually pH 6.0 to 12.0, electrical conductivity is 5000 μS / cm or less, and Ca hardness Or Mg hardness is 0 to 1000 mg CaCO ₃ / L, M alkalinity is 0 to 500 mg CaCO ₃ / L, silica is 0 to 250 mg / L, chloride ion is 0 to 3000 mg / L, sulfate ion is 0 to 3000 mg / L, all Iron is 10 ppm or less, preferably 3 ppm or less, aluminum is 3 mg / L or less, turbidity or suspended solids concentration is 100 degrees or less, preferably 20 degrees or less, the stability index of Ritsner is 3.0 or more, and the saturation index of Langeria Is in the range of 3.0 or less.

  Although the temperature of the to-be-processed water system to which the water treatment agent and water treatment method of this invention are applied is not specifically limited, Usually, it is the range of 0-300 degreeC. Moreover, although the flow rate of the to-be-processed water system to which the water treatment agent and water treatment method of this invention are applied is not specifically limited, Usually, it is the range of 0.1-5.0 m / s.

The half-life of the water system to be treated to which the water treatment agent and the water treatment method of the present invention are applied is not particularly limited, but is usually 300 hours or less. Where the half time is the formula:
Half time [h] = (Retained water amount [m ³ ] / Blowdown water amount [m ³ /h])×0.693
Indicated by

  Along with the copolymer of the present invention of the present invention, or the copolymer of the present invention and a sulfonic acid group-containing polymer, another kind of compound known as a corrosion inhibitor, a scale inhibitor, a scale dispersant, a microbial disorder inhibitor, You may use together well-known compounds, such as an oxygen scavenger, a pH adjuster, a can, an anti-fouling water system anticorrosive, and an antifoamer.

  The compounds as corrosion inhibitors that are preferably used in combination are organic phosphonic acid, phosphonocarboxylic acid, phosphinopolycarboxylic acid, phosphoric acid or phosphate, and molybdate.

  The organic phosphonic acid is an organic compound having one or more phosphono groups in the molecule, specifically, 1-hydroxyethylidene-1,1-diphosphonic acid, aminotrimethylenephosphonic acid, ethylenediaminetetramethylenephosphonic acid. , Diethylenetriaminepentamethylenephosphonic acid, hexamethylenediaminetetramethylenephosphonic acid, and the like, preferably 1-hydroxyethylidene-1,1-diphosphonic acid.

  The phosphonocarboxylic acid is an organic compound having one or more phosphono groups and one or more carboxyl groups in the molecule. Specifically, 2-phosphonobutane-1,2,4-tricarboxylic acid, hydroxyphosphonic acid is used. Nonacetic acid, phosphonopolymaleic acid, phosphonic succinic acid and the like can be mentioned, and 2-phosphonobutane-1,2,4-tricarboxylic acid and phosphonopolymaleic acid are preferable. Here, phosphonocarboxylic acid is commercially available from Rhodia under the trade name BRICORRR288 and from BWA under the trade name BELCOR585. The phosphonocarboxylic acid can be produced, for example, by heating phosphorous acid and monoethylenically unsaturated carboxylic acid in a neutral to alkaline aqueous solvent in the presence of a free radical initiator (for example, special (See Kaihei 4-334392). The phosphonocarboxylic acid can be obtained by reacting a reaction product of hypophosphorous acid with a carbonyl compound or an imine compound with an unsaturated carboxylic acid in the presence of a reaction initiator (see Japanese Patent No. 3284318). ).

  The phosphinopolycarboxylic acid is a compound having one or more phosphino groups and two or more carboxyl groups in the molecule. Specifically, it is a bis-- obtained by reacting acrylic acid and hypophosphorous acid. Poly (2-carboxyethyl) phosphinic acid, bis-poly (1,2-dicarboxyethyl) phosphinic acid obtained by reacting maleic acid with hypophosphorous acid, reacting maleic acid with acrylic acid and hypophosphorous acid Bis-poly [2-carboxy- (2-carboxymethyl) obtained by reacting poly (2-carboxyethyl) (1,2-dicarboxyethyl) phosphinic acid, itaconic acid and hypophosphorous acid Ethyl] phosphinic acid, acrylic acid, a reaction product of 2-acrylamido-2-methylpropanesulfonic acid and hypophosphorous acid, etc., preferably acrylic acid The reaction product of maleic acid and hypophosphorous acid is the reaction product of itaconic acid and maleic acid and hypophosphorous acid. The preparation of phosphinopolycarboxylic acid is usually carried out by heating hypophosphorous acid and monoethylenically unsaturated carboxylic acid in an aqueous solvent in the presence of a free radical initiator, for example, JP-B-54-29316. No. 5, JP-B-5-57992 and JP-B-6-47113. Further, phosphinopolycarboxylic acids are commercially available from Bio Labs under trade names such as BELCLENE500, BELPERSE164, and BELCLENE400.

  In the case where copper or a copper alloy is present in a part of the water-system equipment targeted by the water treatment agent and water treatment method of the present invention, it is preferable to use an azole compound in combination. Examples of the azole compound include tolyltriazole, benzotriazole, substituted benzotriazole, mercaptobenzothiazole and the like.

  Although microbial damage as well as corrosion and scale are major obstacles in water systems, it is particularly preferable to use a microbial damage inhibitor together with the water treatment agent and the water treatment method of the present invention because microbial damage cannot be prevented. Examples of microbial disorder inhibitors used in combination include sodium hypochlorite, calcium hypochlorite, liquefied chlorine, bromine chloride, reaction products of hypochlorite and bromide, chloroisocyanuric acids, chlorodimethylhydantoic acids, bromo Compounds that dissolve in water, such as dimethylhydantoic acids and chlorobromodimethylhydantoic acids, to form hypochlorous acid and / or hypobromite; hydrazine; 2-methylisothiazolin-3-one, 2-methyl-4-chloroisothiazoline -3-one, 2-methyl-5-chloroisothiazolin-3-one, 2-methyl-4,5-dichloroisothiazolin-3-one, 1,2-benzisothiazolin-3-one, 2-n-octyl- 4-isothiazolin-3-one, 4,5-dichloro-2-n-octyl-3 (2H) isothiazoline Isothiazoline compounds; organic bromine compounds such as 2,2-dibromo-2-nitroethanol, 2-bromo-2-nitropropane-1,3-diol, 2,2-dibromo-3-nitrilopropionamide; methylenebisthiocyanate Bis- (1,4-dibromoacetoxy) -2-butene, benzyl bromoacetate, sodium bromide, α-bromocinnamaldehyde, 2-pyridinethiol-1-oxide sodium, bis (2-pyridinethiol-1- Oxide) zinc, 2- (4-thiazolyl) benzimidazole, hexahydro-1,3,5-tris- (2-hydroxyethyl) -S-triazine, bis (trichloromethyl) sulfone, dithiocarbamate, 3,5-dimethyl Rutetrahydro-1,3,5,2H-thiadiazine- -Thion, bromoacetic acid ethylthiophenyl ester, α-chlorobenzoaldoxime acetate, 2,4,5,6-tetrachloroisophthalonitrile, 1,2-dibromo-2,4-dicyanobutane, 3-iodo- Examples include 2-propenylbutylcarbamate, salicylic acid, sodium salicylate, p-oxybenzoic acid ester, and p-chloro-m-xylenol.

In the water treatment agent and the water treatment method of the present invention, the microbial disorder inhibitor preferably used in combination is a compound that generates hypochlorous acid and / or hypobromite, but the amount added is free halogen concentration (free The sum of chlorine and free bromine) is usually 0.05 to ₂ mg / L (in terms of Cl ₂ ).

  In the water treatment agent and water treatment method of the present invention, the form of corrosion targeted is not particularly limited, but overall corrosion, pitting corrosion, crevice corrosion, oxygen concentration cell corrosion, stress corrosion cracking, galvanic corrosion, microbial corrosion, flow induction Local corrosion, erosion corrosion, cavitation corrosion, decomponent corrosion, dezincification corrosion, etc. are included.

  The water treatment agent and the water treatment method of the present invention have a scale-inhibiting effect, but the type of scale to be used is not particularly limited, and carbonate scales such as calcium carbonate and magnesium carbonate; calcium sulfate, barium sulfate, strontium sulfate Sulfate scales such as; phosphate scales such as calcium phosphate, zinc phosphate, iron phosphate, aluminum phosphate; silicates such as magnesium silicate, calcium silicate, aluminum silicate, iron silicate, zinc silicate Scale; amorphous silica scale; magnesium hydroxide; aluminum hydroxide; iron oxide, iron hydroxide, and the like.

  Metals that form a passivated film such as stainless steel and titanium are prone to pitting corrosion and stress corrosion cracking due to crevice corrosion at the scale adhering portion, but in the water treatment agent and water treatment method of the present invention, By preventing scale adhesion, it is possible to indirectly prevent corrosion of a metal that forms a passivation film such as stainless steel or titanium.

  The present invention will be specifically described below, but the present invention is not limited to these examples.

1. Corrosion inhibition test by rotation method (1) Copolymer used in examples (polymer 1)
To a 500 mL five-necked flask, add 20 parts by weight (0.20 mol) of maleic anhydride, 0.03 part by weight of ferrous sulfate heptahydrate and 40 parts by weight of water, and add 48% potassium hydroxide aqueous solution thereto. 23.8 parts by weight (0.20 mol) was added. A cooling tube, a stirrer, a thermometer, a nitrogen introduction tube, and a dropping funnel were attached to the flask, and nitrogen was continuously bubbled while stirring during the entire reaction process. After the liquid was heated to 90 ° C., a solution obtained by dissolving 20 parts by weight (0.15 mol) of itaconic acid and 9.0 parts by weight (0.08 mol) of a 48% potassium hydroxide aqueous solution in 50 parts by weight of water and 35% A solution prepared by dissolving 16 parts by weight of hydrogen peroxide and 0.6 part by weight of sodium persulfate in 24 parts by weight of water was placed in a separate dropping funnel, and dropped over 2 hours while maintaining at 90 ° C. After completion of the dropwise addition, 0.02 part by weight of ferrous sulfate heptahydrate was added and then maintained at 90 ° C. for 2 hours. Itaconic acid-maleic acid (weight ratio 46:54) copolymer having a weight average molecular weight of 800 Got. As a result of measuring the residual monomer by high performance liquid chromatography, itaconic acid reaction rate was 100% and maleic acid reaction rate was 88%.

(Polymer 2 to Polymer 5)
An itaconic acid-maleic acid copolymer having the composition shown in Table 1 was produced by the same production method as that for the polymer 1 except that the amounts of maleic anhydride and itaconic acid were changed.

(Polymer 6, Polymer 7)
Itaconic acid-maleic acid copolymers having the compositions shown in Table 1 were produced by the same production method as that for polymer 1 except that the amounts of hydrogen peroxide and sodium persulfate were changed.

(Polymer 8)
An itaconic acid-fumaric acid (weight ratio 50:50) copolymer was produced by the same production method as the polymer 1 except that 20 parts by weight of fumaric acid was added instead of 20 parts by weight of maleic anhydride.

(Polymer 9)
In a 500 mL five-necked flask, itaconic acid 10 parts by weight (0.08 mol), maleic anhydride 20 parts by weight (0.20 mol), fumaric acid 10 parts by weight (0.09 mol), ferrous sulfate 7 water 0.03 parts by weight of a Japanese product and 75 parts by weight of water were added, and 22.4 parts by weight (0.19 mol) of a 48% aqueous potassium hydroxide solution was added thereto. A cooling tube, a stirrer, a thermometer, a nitrogen introduction tube, and a dropping funnel were attached to the flask, and nitrogen was continuously bubbled while stirring during the entire reaction process. After the liquid was heated to 90 ° C., a solution prepared by dissolving 16 parts by weight of 35% hydrogen peroxide and 0.6 part by weight of sodium persulfate in 24 parts by weight of water was added dropwise over 90 minutes while maintaining the temperature at 90 ° C. After completion of the dropwise addition, the temperature was further maintained at 90 ° C. for 2 hours to obtain a 23.9% aqueous solution of an itaconic acid-maleic acid-fumaric acid (weight ratio 23:54:23) copolymer having a weight average molecular weight of 800. As a result of measuring the residual monomer by high performance liquid chromatography, the reaction rate of itaconic acid was 100%, the reaction rate of maleic acid was 90%, and the reaction rate of fumaric acid was 97%.

(Polymer 10)
Instead of 20 parts by weight of itaconic acid, itaconic acid-maleic acid-acrylic acid (weight ratio 40:40) was prepared by the same production method as polymer 1 except that 23.7 parts by weight of itaconic acid and 11.8 parts by weight of acrylic acid were used. 20) A copolymer was produced.

(2) Polymer and copolymer (polymer 11) used in comparative examples
Itaconic acid-maleic acid by the same production method as Polymer 1 except that 12.7 parts by weight of maleic anhydride and 15.0 parts by weight of itaconic acid and 12.8 parts by weight of acrylic acid instead of 20 parts by weight of itaconic acid An acid-acrylic acid (weight ratio 35:35:30) copolymer was synthesized.

(Polymer 12)
An itaconic acid polymer was synthesized by the same production method as the polymer 9 except that 10 parts by weight of itaconic acid, 20 parts by weight of maleic anhydride and 10 parts by weight of fumaric acid were used instead of 40 parts by weight of itaconic acid.

(Polymer 13)
A maleic acid polymer was synthesized by the same production method as polymer 9 except that 10 parts by weight of itaconic acid, 20 parts by weight of maleic anhydride and 10 parts by weight of fumaric acid were used instead of 40 parts by weight of maleic anhydride.

(Polymer 14)
A fumaric acid polymer was synthesized by the same production method as polymer 9 except that 10 parts by weight of itaconic acid, 20 parts by weight of maleic anhydride, and 10 parts by weight of fumaric acid were replaced by 40 parts by weight of fumaric acid.

(Polymer 15)
Maleic acid-acrylic acid (weight ratio 50:50) co-polymerization by the same production method as polymer 1 except that maleic anhydride is 20 parts by weight and acrylic acid is 23.7 parts by weight instead of itaconic acid 20 parts by weight A coalescence was synthesized.

(Polymer 16)
Maleic acid-acrylic acid (weight ratio 50: 50% by weight) is the same as that of Polymer 1 except that 20 parts by weight of itaconic acid is used instead of 20 parts by weight of maleic anhydride and 20 parts by weight of acrylic acid is used instead of 20 parts by weight of itaconic acid. 50) A copolymer was synthesized.

(Polymer 17)
BAKA-made SOKALAN PA15 (trade name, main component is polyacrylic acid) was used as it was.

(Polymer 18)
A maleic anhydride-ethyl acrylate-styrene (weight ratio 49:25:26) copolymer was synthesized by the method described in Example 1 of Japanese Patent No. 2942991.

(Examples 1 to 10)
In Examples 1 to 10, Polymers 1 to 10 were used in corrosion inhibition tests by the following rotation method, respectively.

(Comparative Examples 1-8)
Polymer 11 for Comparative Example 1, Polymer 12 for Comparative Example 2, Polymer 13 for Comparative Example 3, Polymer 14 for Comparative Example 4, Polymer 15 for Comparative Example 5, Polymer 15 for Comparative Example 6 The polymer 16, the polymer 17 in the comparative example 7, and the polymer 18 in the comparative example 8 were used for the corrosion inhibition test by the following rotation method.

(Comparative Example 9)
In the corrosion inhibition test by the following rotation method, it is a blank to which the polymer of the present invention and other water treatment agents are not added at all.

(Corrosion suppression test procedure by rotation method)
According to JIS K0100-1990 industrial water corrosion test method (rotation method), a test piece of low carbon steel (JIS G 3141SPCC-SB) having dimensions of 50 × 30 × 1 mm and a surface area of 0.316 dm ² is degreased with acetone, dried and weighed. Was measured. Next, the polymers shown in Table 1 were added to the test water so that the concentration of each active ingredient was 10 mg / L. The water quality of the test solution was pH: 8.8, M alkalinity: 300 ppm, calcium hardness: 300 ppm, chloride ion: 212 ppm, and Ritsner index (40 ° C.): 4.5. According to JIS K0100-1990 industrial water corrosion test method (rotation method), 500 mL of the test solution is put into a reflux condenser and a flask with a stirrer and kept in a constant temperature bath at 40 ° C., and the test piece is defined in the test method. The motor of the corrosion test apparatus was attached to a holder of a rotating shaft, immersed in a flask containing a test solution at 40 ° C., and the test piece was continuously rotated at a linear velocity of 0.3 m / sec for 3 days. After 3 days, remove the test piece, remove the corrosive products and scale deposits on the surface with a brush under running water, dry it, measure the weight of the test piece, and calculate the corrosion rate (mdd) using the following formula. did.
Corrosion rate (mdd) = (weight loss of test piece: mg) / [(test piece surface area: dm ² ) × (test days: days)]
Moreover, the test piece was observed with the scanning electron microscope, and the adhesion condition of the scale crystal was confirmed. The results are shown in Table 1.

スケール付着状況：
（−）：付着なし （＋）：小程度の付着 （＋＋）：中程度の付着
（＋＋＋）：かなりの付着

Scale adhesion status:
(-): No adhesion (+): Small adhesion (++): Medium adhesion (++): Significant adhesion

  From the results of Examples 1 to 9 in Table 1, it is a copolymer containing (1) itaconic acid and (2) maleic acid and / or fumaric acid as active ingredients, and is a combination polymerization of (1) and (2) It was found that by adding a copolymer having a ratio of 10 to 90:90 to the target aqueous system, corrosion and scale of the metal in contact with water can be effectively suppressed. In addition, when the results of Example 10 and Comparative Example 1 are compared, a copolymer in which the sum of (1) and (2) is 80% by weight of the monomer composition of the copolymer is added to the target aqueous system, thereby adding water. However, if the sum of (1) and (2) is 70% by weight of the monomer composition of the copolymer, the corrosion and scale of the metal in contact with water can be effectively suppressed. It was found that it cannot be effectively suppressed. In addition, the results of Comparative Examples 2 to 7, which are examples using a copolymer that does not contain (1) itaconic acid and (2) maleic acid and / or fumaric acid as an active ingredient, are inferior to the examples. It has been found that a copolymer containing (1) itaconic acid and (2) maleic acid and / or fumaric acid as an active ingredient is effective in inhibiting corrosion of metal and inhibiting scale. Moreover, even if it compares with the result of the comparative example 8 which is a prior art, the copolymer which contains itaconic acid and maleic acid and / or fumaric acid as an active ingredient shown by Examples 1-10 of Table 1 is shown. It has been found that the water treatment agent and the water treatment method of the present invention using the above have obtained excellent corrosion inhibition effect and scale inhibition effect.

2. Corrosion and scale prevention evaluation test by on-site test method The corrosion prevention effect and scale prevention effect of the combined treatment of the copolymer of the present invention and a sulfonic acid group-containing polymer were evaluated.

(1) Example (Example 11)
The polymer 1 used in the corrosion inhibition test by the rotation method described above and the following sulfonic acid group-containing polymer (1) were added separately and used for the corrosion and scale prevention evaluation test by the on-site test method.
Sulfonic acid group-containing polymer (1):
40% by weight aqueous solution of a copolymer of acrylic acid and 2-acrylamido-2-methylpropanesulfonic acid. [Copolymerization ratio (weight) 60:40, weight average molecular weight 10,000]

(Examples 12 and 13)
The polymer 1 used in the corrosion inhibition test by the rotation method described above and the sulfonic acid group-containing polymer (1) used in Example 11 were added separately, and used for the corrosion and scale prevention evaluation test by the on-site test method. It was.

(Example 14)
The polymer 1 used in the corrosion inhibition test by the rotation method described above and the following sulfonic acid group-containing polymer (2) were added separately and used for the corrosion and scale prevention evaluation test by the on-site test method.
Sulfonic acid group-containing polymer (2):
40% by weight aqueous solution of a copolymer of acrylic acid and 3-allyloxy-2-hydroxy-1-propanesulfonic acid. [Copolymerization ratio (weight) 50:50, weight average molecular weight 5,000]

(Example 15)
The polymer 6 used in the corrosion inhibition test by the rotation method described above and the following sulfonic acid group-containing polymer (3) were added separately and used for the corrosion and scale prevention evaluation test by the on-site test method.
Sulfonic acid group-containing polymer (3):
40% by weight aqueous solution of a copolymer of acrylic acid and isopropyl sulfonic acid.
[Copolymerization ratio (weight) 50:50, weight average molecular weight 10,000]

(Example 16)
The polymer 1 used in the corrosion inhibition test by the rotation method described above was used for the corrosion and scale prevention evaluation test by the on-site test method.

(Example 17)
The polymer 6 used in the corrosion inhibition test by the rotation method described above was used for the corrosion and scale prevention evaluation test by the on-site test method.

(Example 18)
68.4 g of the polymer 1 (active ingredient 18.5% by weight) 68.4 g used in the above-described corrosion inhibition test by the rotation method and 31.6 g of the active ingredient 40% by weight used in Example 11) are mixed to form one liquid. The water treatment agent 1 was prepared so that the weight ratio of the active ingredient of the polymer 1 and the sulfonic acid group-containing polymer (1) was 50:50.
The water treatment agent was used for the corrosion and scale prevention evaluation test by the on-site test method.

(Comparative Example 10)
The sulfonic acid group-containing polymer (1) used in Example 11 was used in an evaluation test for corrosion and scale prevention by an on-site test method.

(Comparative Example 11)
The sulfonic acid group-containing polymer (2) used in Example 14 was used for the corrosion and scale prevention evaluation test by the on-site test method.

(Comparative Example 12)
The sulfonic acid group-containing polymer (3) used in Example 15 was used in an evaluation test for corrosion and scale prevention by an on-site test method.

(Comparative Example 13)
The following polyacrylic acid and the sulfonic acid group-containing polymer (1) used in Example 11 were added separately, and used for corrosion and scale prevention evaluation tests by the on-site test method.
Acrylic acid polymer:
BAKA-made SOKALAN PA20 (trade name, main component is polyacrylic acid) was used as it was. (Molecular weight 2500)

(Comparative Example 14)
In the corrosion and scale prevention evaluation test by the following on-site test method, the water treatment agent or copolymer of the present invention or the sulfonic acid group-containing polymer and other water treatment agents are not added at all.

(Test equipment and test procedure for corrosion and scale prevention evaluation test by on-site test method)
The test apparatus and the test method used for evaluating the method of the present invention were based on the on-site test method of JIS G0593-2002 “Evaluation Test Method for Corrosion and Scale Prevention of Water Treatment Agent”. An outline of the test apparatus is shown in FIG. A carbon steel pipe STKM11A (JIS G3445) having an outer diameter of 12.7 mm and a length of 510 mm was used as a test heat transfer tube. The water capacity of the entire system including the water tank 2 and the piping was 62 L, and the water temperature was controlled by the water temperature controller 9 so that the water temperature of the water tank was 35 ° C. Water is passed through the circulation pump 3 while being controlled by the flow rate adjusting valve 5 so that the flow rate is 210 L / h corresponding to the linear flow rate of 0.3 m / s in the test heat transfer tube evaluation unit, and the heat flux of the heat exchanger 7 is 70 kW. / M ² . The cooling tower 1 used was an induced draft counterflow contact type having a cooling capacity of 1.8 cooling tons. The temperature difference between the circulating water at the inlet and outlet of the cooling tower was 15 ° C., and the amount of evaporated water was 4.4 L / h. The electrical conductivity of the circulating water is continuously measured by the electrical conductivity measuring cell 4 so that the electrical conductivity corresponding to 7 times the concentration is obtained from the electrical conductivity input signal using the electrical conductivity controller 11. The blowdown pump 10 was controlled.

  Yokkaichi city water was used as makeup water 12. The water quality of Yokkaichi city water is pH: 7, electrical conductivity: 13 mS / m, Ca hardness: 38 mg-CaCO 3 / L, Mg hardness: 8 mg-CaCO 3 / L, M alkalinity: 40 mg-CaCO 3 / L, chloride ion: 10 mg / L, sulfate ion: 11 mg / L, silica: 12 mg / L.

  As an initial treatment, Yokkaichi City water is spread in the water tank, and only 200 mg / L of hexametaphosphate sodium salt (average degree of condensation 40) is added as the total concentration of active ingredients of the water treatment agent or polymer and sulfonic acid group-containing polymer or polymer shown in Table 2. 12.5 mg / L was added and circulated at room temperature for 48 hours. Thereafter, the heat load was started, and the concentration reached 5 times 3 days after the start of the heat load. Therefore, blowdown was immediately started to maintain the concentration at 7 times. At the same time as the start of blowdown, only the water treatment agent or polymer shown in Table 2 and the sulfonic acid group-containing polymer or polymer shown in Table 2 are used as active ingredients shown in Table 2 using the water treatment agent injection device 13. Concentration equivalents were added. The test period was one month. After completion of the test, the test heat transfer tube was removed, and the average corrosion rate, maximum corrosion depth, and adhesion rate were measured. The results are shown in Table 2.

  Comparing the results of Examples 11 to 15 and Tables 16 and 17 in Table 2, when the copolymer used in the present invention is used in combination with a sulfonic acid group-containing polymer, further excellent corrosion inhibition effect and scale inhibition effect are obtained. It turns out that it is obtained. Further, the results of Example 11 and Example 18 were not different, and even when the copolymer and the sulfonic acid group-containing polymer were separately added to the target aqueous system, the water in which the copolymer and the sulfonic acid group-containing polymer were mixed in advance was used. It has been found that even if a treatment agent is prepared and the water treatment agent is added to the target water system, the same effect can be obtained. The results of Comparative Examples 10 to 12 show that the sulfonic acid group-containing polymer may be used alone, and the corrosion inhibitory effect and the scale inhibitory effect cannot be obtained. From the results of Comparative Example 13, the sulfonic acid group-containing polymer It is shown that a corrosion inhibitory effect and a scale inhibitory effect may not be obtained when a polymer (polyacrylic acid) other than the copolymer used in the present invention may be used in combination.

3. Example of copolymer polymerization (Reference Example 1)
An itaconic acid-maleic acid copolymer was synthesized by the same production method as polymer 1 except that 48% potassium hydroxide was not added. The itaconic acid reaction rate was 84% and the maleic acid reaction rate was 52%. It was.

(Reference Example 2)
An itaconic acid-maleic acid copolymer was synthesized by the same production method as that of the polymer 1 except that sodium persulfate was not added. The itaconic acid reaction rate was 87% and the maleic acid reaction rate was 70%.

(Reference Example 3)
An itaconic acid-maleic acid copolymer was synthesized by the same production method as that of the polymer 1 except that ferrous sulfate heptahydrate was not added. The itaconic acid reaction rate was 85% and the maleic acid reaction rate was 45. %Met.

  From the results of Reference Examples 1 to 3, in the aqueous polymerization method of the copolymer used in the present invention, any of the amount of alkali metal hydroxide, the amount of polymerization initiator, and the amount of metal catalyst is outside the appropriate range. This indicates that the monomer reaction rate does not increase sufficiently.

  INDUSTRIAL APPLICABILITY The present invention can be used for metal corrosion inhibition and scale inhibition in water systems such as open circulation cooling water systems, closed circulation cooling water treatment agents, transient cooling water systems, boiler water systems, circulating cold / hot water systems, and circulating heating water systems. it can.

DESCRIPTION OF SYMBOLS 1 Cooling tower 2 Water tank 3 Circulation pump 4 Electrical conductivity measurement cell 5 Flow rate adjustment valve 6 Flowmeter 7 Heat exchanger 8 Test piece holder 9 Water temperature control device 10 Blow down pump 11 Electrical conductivity control device 12 Supply water 13 Water treatment Agent injection device

Claims (4)

  (1) a copolymer containing itaconic acid and (2) maleic acid and / or fumaric acid as active ingredients, wherein the blending weight ratio of (1) and (2) is 10-90: 90-10, A water treatment agent comprising, as an active ingredient, a copolymer in which the total of (1) and (2) is 80% by weight or more of the monomer composition of the copolymer.   (1) a copolymer containing itaconic acid and (2) maleic acid and / or fumaric acid as active ingredients, wherein the blending weight ratio of (1) and (2) is 10-90: 90-10, A water treatment method comprising adding a copolymer having a total of (1) and (2) of 80% by weight or more of the monomer composition of the copolymer to a target water system.   (1) a copolymer containing itaconic acid and (2) maleic acid and / or fumaric acid as active ingredients, wherein the blending weight ratio of (1) and (2) is 10-90: 90-10, And the water treatment agent characterized by including a sulfonic acid group containing polymer as an active ingredient with the copolymer whose sum total of (1) and (2) is 80 weight% or more of the monomer composition of a copolymer. (1) a copolymer containing itaconic acid and (2) maleic acid and / or fumaric acid as active ingredients, wherein the blending weight ratio of (1) and (2) is 10-90: 90-10, And the water processing method characterized by adding a sulfonic acid group containing polymer to an object water system with the copolymer whose sum total of (1) and (2) is 80 weight% or more of the monomer composition of a copolymer.

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