AU2002214357B2

AU2002214357B2 - Multifunctional water-treating composition and method of water-treating using the same

Info

Publication number: AU2002214357B2
Application number: AU2002214357A
Authority: AU
Inventors: Dong Jin Choi; Ki Seung Choi; Soon Jong Hahn; Jin Man Kim
Original assignee: Tsk Water Co Ltd
Current assignee: Tsk Water Co Ltd
Priority date: 2000-11-03
Filing date: 2001-11-02
Publication date: 2004-11-18
Anticipated expiration: 2021-11-02
Also published as: KR100683036B1; WO2002036503A1; AU1435702A; JP2004513102A; KR20020034694A; CN1473137A; CN1280213C

Description

WO 02/36503 PCT/KR01/01860 MULTIFUNCTIONAL WATER-TREATING COMPOSITION AND METHOD OF WATER-TREATING USING THE SAME FIELD OF THE INVENTION The present invention relates to a multifunctional water-treating composition and method of water treating using the same. More particularly, the present invention relates to a water-treating composition which has superior stability during storage or use thereof, as well as is capable of suppressing a corrosion, a scale formation and a growth of microorganisms simultaneously, which take place in an open-circulation cooling water system.

BACKGROUNDS OF THE INVENTION In an open-circulation cooling water system, the temperature of cooling water is controlled with equipment that is called a cooling tower. Since air always flows into the water-temperature controlling system having the cooling tower, the system is called as the open-circulation cooling water system. During the recycling of the cooling water, various minerals contained in water are concentrated due to the water-evaporation. And in accordance with a treatment method of used-water, various phenomena that influence the cooling operation take place. These phenomena are largely classified into problems of corrosion, a scale formation and microorganisms.

Simply, the corrosion means a rust formation on a metal material.

Generally, metal is made by refining an oxidized substance, so it has a strong property to return to the oxidized state that is a thermodynamically stable state.

Therefore, it is natural that the corrosion may occur in the open-circulation cooling WO 02/36503 PCT/KR01/01860 water system.

The scale is formed by sediments resulted from the metal corrosion, or by combination of various divalent metal ions in the water with negative ion compounds. As the temperature of the cooling water increases, solubility of metal salt decreases. Thus, the scale is easily formed on a place in the state of a comparatively high temperature due to heat, for example, a freezer or a heat exchanger of the open-circulation cooling water system. If the scale is excessively formed, a pipe may get clogged up and heat transfer efficiency becomes low, which result in the undue energy loss.

Microorganisms such as bacteria, fungi, moss etc can grow well or not according to environmental conditions. Unfortunately, the environments of the cooling tower, including a water temperature, pH, dissolved oxygen content, mineral contents, and sunlight provide very suitable conditions for the growth of microorganisms. If microorganisms, which grow in such a suitable environment, were coagulated each other and were stuck to fillers in the cooling tower, they interfere the flow of water and air, which results in the decrease of the cooling efficiency. Microorganism sludge adhered to the filler in the cooling tower is called a slime. If such slime was adhered to a surface of metal pipe, the partial corrosion due to the microorganism may occur.

It is easily founded that the corrosion, the scale and the slime are generated in various kinds of industrial equipments having water flowing pipes, WO 02/36503 PCT/KR01/01860 including a heat exchanger of a cooling facility. In this case, there may be serious problems including a curtailment of designated life of the cooling system, a reduction of heat transfer efficiency, bacteria infection, an environmental pollution, etc, which result in enormous economic loss.

To overcome above-mentioned problems, various water-treating compositions have developed conventionally. However, the conventional watertreating method uses a corrosion inhibitor, a scale inhibitor, and a microorganism inhibitor separately for the water-treatment. Thus, it is impossible to solve problems of the corrosion, the scale formation and the growth of microorganisms simultaneously with only a chemical composition. For example, a conventional water-treating method suppressed the scale formation by introducing a scale inhibitor, and then suppressed the growth of microorganisms by introducing a microorganism inhibitor. As an example of water-treating composition having such a single effect, a water-treating composition including azole compound and phosphate salt was disclosed in U.S. Pat. No. 4,134,959. Also, U.S. Pat. No.

5,227,133 disclosed a cooling water-treatment method using a composition containing zinc salt, molybdenum salt and phosphate salt, and U.S. Pat. No.

5,156,665 disclosed a method for preventing a growth of the microorganism.

However, the water-treating composition for preventing corrosion and scale formation is less effective in preventing the growth of microorganisms, and the water-treating composition for preventing the growth of microorganisms is less effective in preventing the corrosion and scale formation. Therefore, the use of WO 02/36503 PCT/KR01/01860 the conventional water-treating composition is restrictive, and a user must inject suitable water-treating compositions according to a water condition. The reason that the corrosion inhibitor, the scale inhibitor and the microorganism inhibitor each is developed respectively is because, if they all are mixed to form a composition, the stability of the product is deteriorated, and precipitates are formed due to a lack of compatibility between the respective components. In addition, the possible effects derived from the respective components cannot be performed sufficiently.

SUMMARY OF THE INVENTION As a result of a several-year research in order to solve the abovementioned problems, the present inventors have developed a water-treating composition, which has a superior stability during storage or use thereof, and is capable of solving the problems related to corrosion, a scale formation, and a growth of microorganisms simultaneously in an open-circulation cooling water system.

Accordingly, an object of the present invention is to provide a watertreating composition for a cooling tower which is capable of simultaneously suppressing a corrosion, a scale formation and microorganism growth, and is easy to use, and a method of water-treating using the same, with compared to the conventional a water-treating composition.

Another object of the present invention is to provide a water-treating composition which has superior compatibility between the respective components of the composition, and has superior stability during storage or use of the WO 02/36503 PCT/KR01/01860 composition product, and a method of water-treating using the same.

To achieve the above objects, it is provided a uniform multifunctional water-treating composition comprising at least one component selected from a group consisting of a mixture including azole compound and carboxylate, orthophosphate salt and zinc salt, a microorganism growth inhibitor, a scale formation inhibitor, an organic phosphonate and nitrate. Preferably, 3isothiazolinone can be used as the microorganism growth inhibitor, and acrylate polymer can be used as the scale formation inhibitor. Also preferably, in the water-treating composition, the amount of the microorganism growth inhibitor is from 0.05 to 15% by weight, the amount of the scale formation inhibitor is from to 50% by weight, the amount of the above organic phosphonate is from 0.2 to by weight, wherein the amount is the amount of organic phosphonate ion, and amount of the nitrate is from 0.02 to 20% by weight, wherein the amount is the amount of nitrate ion.

If the orthophosphate salt and/or zinc salt are used, the preferred amount of orthophosphate and/or zinc salt is from 0.1 to 30% by weight, wherein the amount is the total amount of orthophosphate ion and zinc ion. If the mixture including azole compound and carboxylate is used, the preferred amount of azole compound is from 0.01 to 10% by weight, and amount of carboxylate is from 0.2 to by weight, wherein the amount is the amount of carboxylate compound.

In addition, the present invention also provides a water-treating method for preventing a corrosion, a scale formation and a growth of microorganisms, the WO 02/36503 PCT/KR01/01860 method including a step of introducing a multifunctional water-treating composition comprising at least one component selected from a group consisting of mixture including azole compound and carboxylate, orthophosphate salt and zinc salt, a microorganism growth inhibitor, a scale formation inhibitor, an organic phosphonate and nitrate into a cooling water system.

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, the present invention will be described in more detail.

As the inhibitor of the microorganism growth used in the water-treating composition according to the present invention, the conventional inhibitors of the microorganism growth may be used. However, 3-isothiazolinone of the following Chemical Formula 1 is preferable as the inhibitor of the microorganism growth due to the superior compatibility of 3-isothiazolinone with another compounds such as the inhibitor of scale formation, organic phosphonate, azole compound, carboxylate, orthophosphate salt and zinc salt, superior growth suppressing effect on various microorganisms, and longtime-continuing inhibiting property.

[Chemical formula 1] Ro CH3 0 In chemical formula 1, Ro represents hydrogen or chloride.

Specifically, it is more preferred that 2-methyl-4-isothiazolone-3-one in which Ro is a hydrogen in the chemical formula 1, or 5-chloro-2-methyl-4isothiazolone-3-one in which Ro is a chloride in the chemical formula 1 is used. It WO 02/36503 PCT/KR01/01860 is most preferred that mixture of 2-methyl-4-isothiazolone-3-one and 5-chloro-2methyl-4-isothiazolone-3-one with the mix ratio of 1:20 to 20:1 by weight is used.

In the water-treating composition of the present invention, the amount of 3isothiazolinone of chemical formula 1 is preferably 0.05 to 15% by weight in the total amount of the water-treating composition. If the amount of 3-isothiazolinone is less than 0.05% by weight, the sterilization effect is lowered, and if the amount of 3-isothiazolinone is more than 15% by weight, the sterilization effect improves, but the composition is not economical.

As the inhibitor of the scale formation used in the water-treating composition according to the present invention, the conventional inhibitor of the scale formation may be used. However, acrylate polymer of the following Chemical Formula 2 is preferable as the inhibitor of the scale formation due to the superior compatibility of acrylate polymer with another compounds such as the inhibitor of microorganism growth, organic phosphonate, azole compound, carboxylate, orthophosphate salt and zinc salt, and superior preventing effect of scale formation due to divalent metal salts.

[Chemical formula 2]

R

2 Ra I I R-[H C- C-EHC-C R, R R COOX C=O N- R Rs SO ,Y In above chemical formula 2, 1, m, n which can be same or different, are an integer from 0 to 1000. R represents a hydrogen, a methyl or a carboxyl group, WO 02/36503 PCT/KR01/01860 and when R is a carboxyl group, it can be combined with neighboring carbonyl groups to form an anhydrous ring. R 1 and Rs which can be same or different, each represents a hydrogen, an alkyl group, a hydroxyl group or a phosphono group. R 2 and R 3 which can be same or different, each represents a hydrogen or an alkyl group of C1-C2. R 4 represents a hydrogen, an alkyl group of C1-C5, and represents an alkyl group of C1-C8 or an aralkyl group of C8-C10. X and Y which can be same or different, each represents a hydrogen, an alkyl group of C1or a hydroxyalkyl group of C1-C5. Besides, Ro includes one or more group selected from the following chemical formulas 3, 4 and [Chemical formula 3] Rs

COOR,

[Chemical formula 4] -{HC-CH

C=O

CHa [Chemical formula

R,

2 -H,C-C

C=O

N

R

1 3 R 14 In above chemical formulas, R 6 and R 12 which can be same or different, each represents a hydrogen or an alkyl group of C1-C2, and R 13 and R 14 which can be same or different, each represents a hydrogen, an alkyl group of C1-C8, a WO 02/36503 PCT/KR01/01860 cycloalkyl group of C6-C8, a benzyl group or a group of the following chemical formula 6. R 7 represents an alkyl group of C1-C6, an aralkyl group of C6-C10 or a group of the following chemical formula 6.

[Chemical formula 6]

R

9

-[H

2 C-C-0-R,] In chemical formula 6, i is 1,2 or 3, and R 9 represents a hydrogen or an alkyl group of C1-C2, Rio represents a hydrogen or an alkyl group of C1-C6.

It is preferred that the amount of acrylate polymer in the water-treating composition of the present invention is 0.5 to 50% by weight. If the amount of acrylate polymer is less than 0.5% by weight, inhibition ability of the scale formation is lowered, and if the amount of acrylate polymer is more than 50% by weight, the inhibition ability of the scale improves, but the composition is not economical.

To enhance the compatibility between the components and the corrosionpreventing property, the water-treating composition of the present invention further includes at least one component selected from a group consisting of mixture including azole compound and carboxylate, orthophosphate salt and zinc salt.

As the azole compound, benzotriazole, tolyltriazole, mercaptobenzothiazole or mixtures thereof is preferably used, and benzotriazole is more preferably used. As the carboxylate, carboxylate compounds having carbon numbers of 3 to 12 or mixtures thereof is preferably used, and citrate is more preferably used. Preferably, the amount of azole compound in the water- WO 02/36503 PCT/KR01/01860 treating composition is 0.01 to 10% by weight, and more preferably 0.05 to 8% by weight. If amount of azole compound is less than 0.01% by weight, a prevention of the corrosion could not be performed efficiently, and if amount of azole compound is more than 10% by weight, it is economically inefficient. Preferably, the amount of carboxylate is 0.2 to 40% by weight, wherein the amount is the amount of the carboxylate compound, and more preferably 0.5 to 30% by weight. If amount of the carboxylate compound is less than 0.2% by weight, a prevention of the corrosion could not be performed efficiently, and if amount of carboxylate compound is more than 40% by weight, it is economically inefficient.

As orthophosphate, orthophosphate mono basic, orthophosphate di basic, orthophosphate tri basic, phosphoric acid, or mixtures thereof is preferably used, and phosphoric acid is more preferably used. As the zinc salt, zinc chloride, zinc sulfate, zinc nitrate, or mixtures thereof is preferably used. Preferably, the amount of orthophosphate salt and/or zinc salt in the water-treating composition is 0.1 to 30% by weight, wherein the amount is the total amount of the respective ion, namely, the total amount of orthophosphate ion and zinc ion. More preferably, the amount of the zinc ion is 0.1 to 20% by weight, and the amount of the orthophosphate ion is 0.5 to 30% by weight. If amount of zinc ion is less than 0.1% by weight, a prevention of the corrosion could not be performed efficiently, and if amount of zinc ion is more than 20% by weight, it will cause bad influence to fish and shellfishes when discarded as sewage. If amount of the orthophosphate ion is less than 0.5% by weight, a prevention of the corrosion could not be performed efficiently, and if amount of orthophosphate ion is more than 30% by WO 02/36503 PCT/KR01/01860 weight, it will cause the scale of calcium phosphate.

As the organic phosphonate of the present invention, hydroxyethylidene diphosphonic acid, hydroxyphosphono carboxylic acid, aminotrimethylene phosphonic acid, phosphonobuthane tricarboxylic acid, ethylenediamine tetramethylidene phosphonic acid or mixtures thereof is preferably used.

Preferably, the amount of organic phosphonate in the water-treating composition is 0.2 to 30% by weight, wherein the amount is the amount of the organic phosphonate ion. If amount of the organic phosphonate ion is less than 0.2 wt%, prevention of the corrosion and scale formation could not be performed efficiently, and if amount of the organic phosphonate ion is more than 30 wt%, it is economically inefficient.

Nitrate used in the present invention improves the compatibilities between the inhibitor of microorganism growth, the inhibitor of scale formation, organic phosphonate, azole compound, and carboxylate, and also improves the storage stability. As the nitrate, magnesium nitrate, copper nitrate, etc can be used.

Preferably, the amount of the nitrate in the water-treating composition of the present invention is 0.02 to 20% by weight, wherein the amount is the amount of the nitrate ion. If amount of the nitrate ion is less than 0.02% by weight, the anticorrosive ability and storage stability of product is deteriorated, and if amount of the nitrate ion is more than 20% by weight, it is economically inefficient.

The water-treating composition of the present invention is preferably introduced into the cooling water so that the concentration of the composition is WO 02/36503 PCT/KR01/01860 from l ppm to 500,000ppm, The water-treating composition of the present invention is effectively used to inhibit the scale formation and the corrosion, which can be occurred in various industrial water flowing pipes such as cooling tower and heat exchanger. Therefore, the water-treating composition of the present invention is preferably used for the open-circulation cooling water system or the various water flowing cooling system. Among them, the water-treating composition of the present invention is more preferably used for the opencirculation cooling water system in which the corrosion and the growth of the microorganism induce more serious problems.

The following examples are provided for better illustration of the present invention, but nothing therein should be taken as a limitation of the invention.

[Example 1-3 and Comparative example 1-3] The water treating compositions including azole compound, carboxylate, orthophosphate salt, zinc salt, acrylate copolymer, organic phosphonate, isothiazolinone, or nitrate were dissolved into water so that the amounts of the effective ingredients in the test water-samples are as shown in Tables 1 and 2 (Examples 1-9) and Tables 3 and 4 (Comparative examples The tests for inhibiting the corrosion, the scale formation, the microorganism growth were conducted.

[Table 1] The amounts of the each component in the water-treating program in which the compositions of the present invention dissolve (Example 1-3) WO 02/36503 PCT/KR01/01860 Amounts (ppm) Components Ex. 1 Ex. 2 Ex. 3 Azole compound 0.5 1 2 Carboxylate 5 7.5 Acrylate polymer 5 7.5 Organic 4 7 phosphonate Isothiazolinone 1.5 2.0 Nitrate ion 2.5 4 [Table 2] The amounts of the each component in the water-treating program in which the compositions of the present invention dissolve (Example 4-9) Amounts (ppm) Components Ex.4 Ex.5 Ex.6 Ex.7 Ex.8 Ex.9 Phosphate ion 8 6 4 0 0 0 Zinc ion 0 0 0 2 2.5 3 Acrylate polymer 5 7.5 10 5 7.5 Organic phosphonate 4 6 8 4 6 8 Isothiazolinone 1.5 2.0 2.5 1.5 2.0 Nitrate ion 2.5 4 6.5 2.5 4 [Table 3] The amounts of the each component in the water-treating program in which the conventional compositions dissolve (Comparative Examples 1-3) Amounts (ppm) Components Comparative Comparative Comparative Ex.1 ex.2 ex.3 Azole compound 0 0 1 Carboxylate 0 2.5 0 Acrylate polymer 0 0 0 Organic phosphonate 0 0 2 Isothiazolinone 0 0.8 0 WO 02/36503 PCT/KR01/01860 Nitrate ion 0 6.5 [Table 4] The amounts of the each component in the water-treating program in which the conventional compositions dissolve (Comparative Examples 4-6) Amounts (ppm) Components Comparative Comparative Comparative Ex.4 ex.5 Ex.6 Orthophosphate ion 8 0 0 Zinc ion 0 0 2 Acrylate polymer 0 0 0 Organic phosphonate 0 2 0 Isothiazolinone 0.8 0 0.8 Nitrate ion 6.5 6.5 In Tables 1-4, the organic phosphonate represents hydroxyethylidene diphosphonic acid [HEDP of LONZA Co., Ltd.], and the acrylate polymer is Belclenece 400 (product of FMC Co., Ltd), and the isothiazolinone is SKYBIO WG(product of SK chemical Co., Ltd). The used azole compounds is benzotriazole, and the used carboxylate is citric acid. As the salts to produce orthophosphate, zinc, and nitrate ion, phosphoric acid, zinc chloride, and magnesium nitrate are used respectively.

A. The corrosion test The corrosion test was carried out with the Rotating corrosion tester.

Carbon steel test specimen was rotated at a rotation speed of 170 rpm, airinjection condition of 10CC/min, and temperature of 30 C, in order to determine the corrosion rate of the carbon steel. The concentrations of the components of 14 WO 02/36503 PCT/KR01/01860 water-treating compositions of the present invention shown in Tables 1 and 2, and the concentrations of the components of conventional water-treating compositions shown in Table 3 and 4 are maintained in water samples having the properties shown in the following Table 5. The carbon steel was digested for five days.

The corrosion rate [mdd, mg/(dm 2 day)] based upon weight loss of the carbon steel was determined and the results were shown in Table 6.

[Table 5] The water samples used in the corrosion test Water Properties1 2 #1 #2 #3 PH 7.5 Calcium hardness (ppm) 100 200 300 M-alkalinity (ppm) 80 100 120 Total hardness (ppm) 120 240 360 Chlorine ion (ppm) 80 160 240 The pH of the water sample was adjusted with 0.1N sodium hydroxide aqueous solution and 0.05N sulfuric acid aqueous solution. The calcium hardness, the M-alkalinity, the magnesium hardness and amount of the chlorine ion were adjusted with calcium chloride, sodium bicarbonate, magnesium sulfate and sodium chloride, respectively. The total hardness represents the sum of the calcium hardness and the magnesium hardness.

[Table 6] The corrosion test result of Examples 1-9 and Comparative examples 1-6 The corrosion rate (mdd) Components Water #1 Water #2 Water #3 Example 1 7.68 8.25 9.43 Example 2 5.35 6.10 7.89 WO 02/36503 PCT/KR01/01860 Example 3 3.73 4.82 5.43 Example 4 4.86 6.35 7.53 Example 5 4.98 6.21 6.08 Example 6 5.96 7.52 7.43 Example 7 4.56 4.72 4.64 Example 8 3.86 4.08 4.21 Example 9 3.08 2.86 3.27 Comparative ex.l 312.39 212.29 167.06 Comparative ex.2 287.12 198.34 161.18 Comparative ex.3 33.28 42.37 58.06 Comparative ex.4 20.08 27.48 18.86 Comparative ex.5 35.36 45.03 67.94 Comparative ex.6 20.08 27.48 18.86 mdd mg/(dm 2 day) As shown in Table 6, the corrosion preventing abilities of compositions of Examples 1 to 3 are much superior to them of Comparative examples 1-3. And the corrosion preventing abilities of compositions of Examples 4 to 9 are much superior to them of Comparative examples 4-6 which are including orthophosphate, zinc salt or organic phosphonate, separately. Thus, the uniform multifunctional water-treating composition of the present invention is stable in the mixed state and has superior corrosion preventing property.

B. Inhibition test of the scale formation Test solution was tightly sealed up, and was reserved for 24 hours at The test solution was filtered with 0,45 Ipm filter, then scale inhibitor efficiency was determined by measuring the total hardness. The concentrations of the components of water-treating compositions of the present invention shown in Tables 1 and 2, and the concentrations of the components of conventional watertreating compositions shown in Table 3 and 4 are maintained in water samples 16 WO 02/36503 PCT/KR01/01860 having the properties shown in the following Table 7. The scale inhibitor efficiencies were calculated with the following mathematical formula 1, and the results were shown in Table 8.

[Mathematical formula 1] scale inhibitor efficiency Ce/Ct x 100 In mathematical formula 7, the Ct represents total hardness of water sample before the test, and the Ce represents total hardness of water sample after the test.

[Table 7] The water sample used in the scale-inhibition test Water Properties 2 #1 #2 #3 Calcium hardness (ppm) 100 200 300 M-alkalinity (ppm) 100 200 300 Chlorine ion (ppm) 80 160 240 In the water samples of Table 7, calcium hardness was adjusted with calcium chloride, and M-alkalinity and chlorine ion were adjusted with sodium bicarbonate and sodium chloride, respectively.

[Table 8] The scale-inhibition test result of Examples 1-9 and Comparative examples 1-6 scale inhibitor efficiency Components Water #1 Water #2 Water #3 Example 1 100 98 Example 2 100 100 100 Example 3 100 100 100 WO 02/36503 PCT/KR01/01860 Example 4 98 98 Example 5 100 100 98 Example 6 100 100 100 Example 7 100 100 98 Example 8 100 100 100 Example 9 100 100 100 Comparative ex.1 90 63 33 Comparative ex.2 88 68 Comparative ex.3 93 78 67 Comparative ex.4 86 58 29 Comparative ex.5 93 78 67 Comparative ex.6 86 58 29 As shown in Table 8, the scale inhibitor efficiencies of examples 1-9 according to the present invention are superior to them of comparative examples 1-6.

C. The microorganism inhibition test The solutions including 8 species microorganisms (8 species of Enterobacter aerogens ATCC 13048, Escherichia coil ATCC 11229, Micrococcus luteus ATCC 9341, Pseudomonas aeruginosa ATCC 15442, Klebsiella pneumoniae ATCC 1560, Staphylococcus edidermis ATCC, Staphylococcus aureus ATCC 6538, Bacillus subtilis ATCC 6984) were introduced into samples under the conditions of 30°C, 170rpm, and air-injection condition of 10ml/min. After two days, concentration reductions of microorganisms were measured. At this time, the microorganism solutions were produced to the concentration of 10 6 CFU/ml, and introduced into the water sample having the properties shown in Table 9 so that the concentrations of microorganisms were 105 CFU/ml. In addition, the concentrations of the components of water-treating compositions of 18 WO 02/36503 PCT/KR01/01860 the present invention shown in Tables 1 and 2, and the concentrations of the components of conventional water-treating compositions shown in Table 3 and 4 are maintained in the water samples. The measured concentration reductions of microorganisms are shown in the following Table [Table 9] The water sample used in inhibition test of the microorganism growth Water Properties 1 4 #1 #2 #3 PH 7.5 Calcium hardness (ppm) 100 200 300 M-alkalinity (ppm) 80 100 120 Total hardness (ppm) 120 240 360 Chlorine ion (ppm) 80 160 240 Number of initial 10 5 10 5 10 microorganism (CFU/m) [Table 10] The inhibition test result of the microorganism growth of Examples 1-9 and Comparative examples 1-6 Number of microorganism (CFU/ml) Components Water #1 Water #2 Water #3 Example 1 101 102 Example 2 0 0 101 Example 3 0 0 0 Example 4 10 1 102 102 Example 5 0 101 101 Example 6 0 0 0 Example 7 101 10 10 2 Example 8 0 101 101 Example 9 0 0 0 Comparative ex.1 10 7 108 108 WO 02/36503 PCT/KR01/01860 Comparative ex.2 10 3 10 4 10 4 Comparative ex.3 10 7 108 108 Comparative ex.4 10 3 10 4 10 4 Comparative ex.5 i0 7 108 108 Comparative ex.6 10 3 10 4 10 4 CFU/m Colony Forming Unit/mi As shown in Table 10, if the water treating compositions of the present invention were used, inhibition rate of microorganism is very high, compared to the cases of using the inhibitor of microorganism growth separately or using the inhibitor of microorganism growth with other material. Therefore, it is clear that the water-treating composition of present invention is stable in mixed state and has better inhibition effect of microorganism growth.

In conclusion, the water-treating composition for the open-circulation cooling water system according to the present invention simultaneously improves the functions of preventing metal corrosion, scale formation and microorganism growth, and has the superior stability during storage or use thereof.

The water-treating composition of present invention has longtimecontinuing sterilizing power, and its sterilization effect for all microorganisms is very effective in the open-circulation cooling water system. In addition, the composition can prevent both of the anode reaction and the cathode reaction of the corrosion reactions. Therefore, the composition effectively reduces the corrosion, which can occur on metal surface. In addition, the acrylate copolymer and organic phosphonate modify the crystalline structure of the scale of the divalent metal salt, and thus effectively prevent the scale formation. Thus, the water-treating composition according to the present invention simultaneously WO 02/36503 PCT/KR01/01860 improves the functions of preventing metal corrosion, scale formation and microorganism growth.

Claims

1. A multifunctional water-treating composition comprising: c at least one component selected from a group consisting of a mixture including azole compound and carboxylate, orthophosphate salt and zinc salt; In 5 a microorganism growth inhibitor; o a scale formation inhibitor; 0 an organic phosphonate; and a nitrate.

2. The multifunctional water-treating composition according to claim 1, wherein the microorganism growth inhibitor is a 3-isothiazolinone, and the scale formation inhibitor is acrylate polymer.

3. The multifunctional water-treating composition according to claim 2, wherein the 3-isothiazolinone is a compound represented by the following chemical formula 1, and the acrylate polymer is a polymer represented by the following chemical formula 2. [Chemical formula 1] CH 3N II 0 [Chemical formula 2] R R, EHC-1- H,C-C h4R, 1R. R COOX C=0 N-IR, ZSO .Y 23 where, in chemical formula 1, Ro represents hydrogen or chloride; and in chemical formula 2, 1, m, n which can be same or different, are an integer from 0 to 1000; R represents a hydrogen, a methyl or a carboxyl group, and when R is a oJ carboxyl group, it can be combined with neighboring carbonyl groups to form an Ni 5 anhydrous ring; R 1 and R 8 can be same or different, each represents a hydrogen, an alkyl group, a hydroxyl group or a phosphono group; R 2 and R3 can be same or different, each represents a hydrogen or an alkyl group of C1-C2; R 4 represents a hydrogen, an alkyl group of C1-C5, and R 5 represents an alkyl group of Cl-C8 or an aralkyl group of C8-C1; X and Y can be same or different, 10 each represents a hydrogen, an alkyl group of Cl-C5 or a hydroxyalkyl group of N Cl-C5; and R 0 includes one or more group selected from the following chemical formulas 3, 4 and [Chemical formula 3] COOR, [Chemical formula 4] -w 2 C-CH (=O I CH, [Chemical formula I C=0 RIN R.1 1_ -24- 0 O where, in the above chemical formulas, R 6 and R 12 can be same or different, Seach represents a hydrogen or an alkyl group of C1-C2; and R 1 3 and R 14 can be O same or different, each represents a hydrogen, an alkyl group of C1-C8, a c cycloalkyl group of C6-C8, a benzyl group or a group of the following chemical formula 6; and R 7 represents an alkyl group of C1-C6, an aralkyl group of C6- or a group of the following chemical formula 6: In [Chemical formula 6] 0 Rg -H-C-OC -0-R o where, in chemical formula 6, i is 1, 2 or 3, and R 9 represents a hydrogen or an alkyl group of C1-C2, and Rio represents a hydrogen or an alkyl group of C1-C6.

4. The multifunctional water-treating composition according to claim 3, wherein the 3-isothiazolinone is a mixture of 2-methyl-4-isothiazolone-3-one and chloro-2-methyl-4-isothiazolone-3-one with the mix ratio of 1:20 to 20:1 by weight.

The multifunctional water-treating composition according to any one of the preceding claims, wherein the azole compound is benzotriazole, tolyltriazole, or mercaptobenzothiazole.

6. The multifunctional water-treating composition according to any one of the preceding claims, wherein the carboxylate is at least one compound selected from the group consisting of carboxylate compounds having carbon numbers of 3 to 12.

7. The multifunctional water-treating composition according to any one of the preceding claims, wherein the orthophosphate salt is phosphoric acid. 25 8

8. The multifunctional water-treating composition according to any one of the c preceding claims, wherein the zinc salt is at least one compound selected o from the group consisting of zinc chloride, zinc sulfate, and zinc nitrate. 0 N

9. The multifunctional water-treating composition according to any one of the preceding claims, wherein the organic phosphonate is at least one compound selected from the group consisting of hydroxyethylidene diphosphonic acid, hydroxyphosphono carboxylic acid, aminotrimethylene phosphonic acid, N phosphonobuthane tricarboxylic acid, and ethylenediamine tetramethylidene o phosphonic acid. 0

10.The multifunctional water-treating composition according to any one of the preceding claims, wherein the nitrate is at lest one compound selected from the group consisting of magnesium nitrate, and copper nitrate.

11.The multifunctional water-treating composition according to any one of the preceding claims, wherein the amount of the microorganism growth inhibitor is from 0.05 to 15% by weight, the amount of the scale formation inhibitor is from 0.5 to 50% by weight, the amount of the organic phosphonate is from 0.2 to 30% by weight (expressed as organic phosphonate ion), the amount of the azole compound is from 0.01 to 10% by weight, the amount of carboxylate is 0.2 to 40% by weight, and the amount of the nitrate is from 0.02 to 20% by weight (expressed as nitrate ion).

12. The multifunctional water-treating composition according to any one of claims 1 to 10, wherein the amount of microorganism growth inhibitor is from 0.05 to by weight, the amount of the scale formation inhibitor is from 0.5 to by weight, the amount of the organic phosphonate is from 0.2 to 30% by weight (expressed as organic phosphonate ion), the amount of orthophosphate salt and/or zinc salt is from 0.1 to 30% by weight (expressed as orthophosphate ion and zinc ion), and the amount of the nitrate is from 0.02 to 20% by weight (expressed as nitrate ion). 1 -26- o

13.A water-treating method comprising the step of introducing a multifunctional N water-treating composition comprising at least one component selected from c to a group consisting of mixture including azole compound and carboxylate, 0 orthophosphate salt and zinc salt; a microorganism growth inhibitor; a scale C 5 formation inhibitor; an organic phosphonate; and nitrate into a cooling water system. t

14.The water-treating method according to claim 13, wherein the water-treating ccomposition is introduced into the cooling water system with a concentration oof from 1 ppm to 500,000ppm.

15.A multifunctional water-treating composition substantially as herein described with reference to the description of any one of examples 1 to 3. Dated this Twenty Second day of October 2004. SK Chemicals Co., Ltd Applicant Wray Associates Perth, Western Australia Patent Attorneys for the Applicant .1