JPH0780470A - Water treatment agent for sterilization - Google Patents

Abstract

(57) [Summary] [Purpose] It has excellent bactericidal effect of Legionella bacteria at a minute concentration,
A water treatment agent that is not corrosive to metals and is easy to handle. [Structure] A sterilizing water treatment agent containing a specific halocyanoacetamide derivative and a water-soluble cationic polymer as active ingredients. [Effect] The water treatment agent of the present invention, which is used in combination with a specific halocyanoacetamide derivative and a water-soluble cationic polymer, exerts an extremely excellent effect on sterilization of Legionella bacteria generated in a cooling water system and corrodes metals. It is also non-irritating and is not irritating to the human body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disinfecting water treatment agent, and more particularly to a disinfecting water treatment agent in a cooling water system in which Legionella bacteria are generated.

[0002]

2. Description of the Related Art With the recent development of industry, a large amount of industrial water is required. In addition to industrial tap water, seawater, lake water, river water, groundwater, etc. are used as water sources for water.

Various microorganisms inhabit these waters, and among these microorganisms, many continue to proliferate due to the water quality and the environment in which they exist, and cause various obstacles. For example, when used as cooling water, microorganisms that live in the water multiply and grow on the walls of water facilities to form slime, which causes problems such as lower heat exchange rates and poor running water. To do.

In particular, in the circulating use of water, in the case of an open type using open type cooling, etc., the circulating water is forcibly aerated and comes into contact with air in a part of the system, and the sunlight is irradiated. Promotes the reproduction of microorganisms such as bacteria and algae. In addition, a similar problem occurs in the cooling water system in which small cooling towers are installed in the air conditioning and heating / cooling equipment of buildings and factories.

By the way, recently, Legionella bacteria detected in such a cooling water system has become a serious problem. Legionella is a gram-negative elongated bacterium, and its optimum growth temperature is 35 to 36 ° C, which matches the temperature of cooling water, and is a symbiotic bacterium that obtains a nutritional source from algae, heterotrophic bacteria, etc.
The cooling water system in which the microorganisms are easily propagated as described above provides a suitable growth environment. Legionella bacteria are caused by the cooling water in which the Legionella bacteria proliferate are scattered from the cooling tower, or in the case of air conditioning equipment, the splash of cooling water contaminates the air and enters the air conditioning facility from the outside air intake and enters the legionella of the indoor air. It is known to cause bacterial contamination and infect the human body. Infections caused by Legionella bacteria are called veterans' illnesses, which may cause symptoms similar to pneumonia, and may even lead to death, which requires countermeasures.

As a method for preventing the growth and growth of Legionella bacteria in cooling water, (a) the addition of a bactericidal agent or a slime control agent to indirectly remove the nutrients of Legionella bacteria to prevent the growth of Legionella bacteria. (B) Keep the cooling tower clean by regularly cleaning the cooling water system with a chemical cleaning agent such as hydrogen peroxide. And (c) Measures such as killing the Legionella bacteria themselves by adding a bactericide are considered.

[0007] However, the above method (a) is poor in actively eliminating Legionella bacteria, it is difficult to apply it to a cooling water system in which Legionella bacteria have already been generated, and it is practically possible to completely suppress the growth. It is difficult. Also,
Although the method (b) is temporarily effective, it cannot be expected to prevent permanent outbreak of Legionella. Therefore, the method (c) is considered to be the most effective and reliable method.

Conventionally, as bactericides effective against Legionella bacteria, glutaraldehyde, isothiazolone-based and bromonitroalcohol-based agents are known. However, when applied to an actual cooling water system, these drugs require a considerably high concentration for sterilization, and the effects are poor in sustainability, and it is necessary to continuously add the drugs. Not only is it economically problematic. Also,
Particularly, the isothiazolone-based drug, which is considered to be the most effective among conventional drugs, is highly corrosive to metals and irritates the skin of the human body, which is a safety problem.

Therefore, the most preferable method for sterilizing the Legionella bacterium has been to combine the above-mentioned (a) and (b) and further use the (c) bactericide. However, this method also needs to interrupt the operation of the cooling water system for chemical cleaning, not only becomes economically expensive, but also has a sufficient effect because the fungicide is fundamentally poor in efficacy. The reality is that it often does not work.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an economical and safe water treatment agent for sterilizing Legionella bacteria, which has an excellent bactericidal effect on Legionella bacteria at a minute concentration.

[0011]

[Means for Solving the Problems] The inventors of the present invention have conducted extensive studies on a drug capable of sterilizing Legionella bacteria in an actual cooling water system even at a very small concentration, and have found that a halocyanoacetamide derivative and a certain cationic polymer. The present invention has been made by finding that it is extremely effective to use a combination of and.

That is, the present invention is a bactericidal water treatment agent containing a halocyanoacetamide derivative represented by the general formula (1) and a cationic polymer represented by the general formula (2) or (3) as active ingredients. Pertain to.

[Chemical 3] (In the formula, X is a halogen atom, Y is a halogen atom or a hydrogen atom, and R ¹ is a hydrogen atom or a lower alkyl group.)

[Chemical 4]

Examples of the halocyanoacetamide derivative represented by the general formula (1) in the present invention include monochlorocyanoacetamide, monobromocyanoacetamide, dichlorocyanoacetamide, dibromocyanoacetamide, N-methyldibromocyanoacetamide and the like. . Among these compounds, it is preferable to use dibromocyanoacetamide (hereinafter, referred to as DBNPA) from the viewpoint of performance and easy availability of the preparation as a commercial product.

The cationic polymer represented by the general formula (2), poly [hydroxyethylene (dimethylimino) ethylene (dimethylimino) methylene chloride] in the present invention is described in, for example, Japanese Patent Publication No. 55-49042. As obtained, it is obtained as a reaction product of N, N, N ′, N′-tetramethylethylenediamine and epichlorohydrin.

The cationic polymer represented by the general formula (3), poly [oxyethylene (dimethylimino) ethylene (dimethylimino) methylene chloride], is described in, for example, Japanese Patent Publication No. 53-23377. N,
Obtained as a reaction product of N, N ', N'-tetramethylethylenediamine and dichloroethyl ether.

Of both compounds, the cationic polymer represented by the general formula (2) is generally commercially available as a preparation (for example, manufactured by Buckman Co., trade name WSCP, 60% active ingredient) and easily available. It is preferable from the point.

By the way, the halocyanoacetamide derivative used in the present invention is known as a drug having a bactericidal action against Legionella. However, it is generally said that the effect of the halocyanoacetamide derivative on Legionella bacteria is weaker than that of halogenated aliphatic nitroalcohol such as bronopol, and in fact, according to the study by the present inventors, in the actual cooling water system at a concentration up to about 100 ppm. Almost no bactericidal action was observed. Halocyanoacetamide derivatives such as DBNPA are expensive compounds, and it is difficult to put them into practical use because it is economically problematic to use them in amounts of 100 ppm or more.

On the other hand, the halocyanoacetamide derivative is
It is a highly safe drug without the risk of corroding metals, and can be said to be a preferred drug from the viewpoint of secondary damage and the environment.

The cationic polymer used in the present invention is
It is known to be effective as an algaecide as described in the above-mentioned publication. However, as a result of examination by the present inventors, the bactericidal action against the Legionella bacterium is extremely poor, and almost no effect is observed even when used at a concentration of about 1000 ppm.

As a result of various investigations conducted by the present inventors, the use of the above halocyanoacetamide derivative and the cationic polymer in combination was extremely excellent and could not be expected at all when used alone. It was confirmed that the above effect was exhibited.

In the present invention, the halocyanoacetamide derivative and the cationic polymer must be present in the water system at the same time, but these agents may be added individually to the water system, or both may be mixed in advance. May be added. Usually, it is preferable to use it as a premixed mixture because it is convenient in terms of work.

In the present invention, the compounding ratio of the both is generally 1 to 20% by weight of the halocyanoacetamide derivative and 5 to 5 of the cationic polymer.
It is in the range of 0% by weight. The balance may be usually mixed with water as a solvent, but a hydrophilic solvent such as alcohol may be used.

The concentration of the halocyanoacetamide derivative added to the water system is from 1 to 40 ppm, and the cationic polymer is from 5 to 5.
It is preferable to set it in the range of 100 ppm, but due to the synergistic effect of the combination, a bactericidal effect is usually obtained when the halocyanoacetamide derivative is 20 ppm or less and the cationic polymer is 50 ppm or less. In order to obtain a better synergistic effect, the compounding ratio of the halocyanoacetamide derivative and the cationic polymer or the concentration ratio of addition to the water system is 1: 5 to 1: 1.
It is preferable to set it as the range.

Thus, the bactericidal water treatment agent of the present invention is not only excellent in performance but also a cationic polymer as well as a halocyanoacetamide derivative, which is a safe chemical without corrosiveness to metals and is excellent in economical efficiency. .

The bactericidal water treatment agent of the present invention has an excellent bactericidal effect by itself, and therefore, it has a sufficient bactericidal effect even if it is added to a water system in which Legionella bacteria have already propagated. It is of course possible to use after cleaning the water system with a chemical cleaning agent such as hydrogen. Further, the disinfecting water treatment agent of the present invention exhibits an excellent disinfecting action also on algae and bacteria in water systems, and also has a large effect of indirectly inhibiting the growth of Legionella.

[0026]

EXAMPLES Next, the present invention will be specifically described with reference to Examples.
The present invention is not limited to the following examples unless it exceeds the gist.

Example 1. The bactericidal efficacy test of the agent of the present invention was carried out by using the cooling water sampled from the on-site air conditioning system open type circulating cooling water system in which the presence of Legionella bacteria was confirmed as the test water.

The agent of the present invention was adjusted to a predetermined concentration in the test water, and the number of surviving bacteria after 20 hours of action was calculated as BCYEα.
The measurement was carried out by a conventional method using a medium and culturing at 37 ° C. for 3 days. The water quality of the test water is as shown in Table-1, and the number of surviving bacteria at the time of the test was 4.1 × 10 ⁵ cells / 100 ml.

In this embodiment, the halocyanoacetamide derivative is dibromocyanoacetamide (DBNP).
A), a 50% aqueous solution of poly [2-hydroxyethylene (dimethylimino) ethylene (dimethylimino) methylene chloride] molecular weight 6000 represented by the general formula (2) as a cationic polymer (hereinafter referred to as compound A),
Poly [oxyethylene (dimethylimino) ethylene (dimethylimino) methylene chloride] represented by the general formula (3) was used in advance by using 50% aqueous solutions (hereinafter referred to as compound B) each having a molecular weight of 5,000, and tested. . The results are shown in Table-2.

[0030]

[Table 1]

[0031]

[Table 2] The mixing ratio is% by weight.

Example 2 A bactericidal efficacy test was conducted in the same manner as in Example 1. In addition, although the chemicals used in this example are the same as those in Example 1, each of them was individually added and tested by varying the degree of addition. The results are shown in Table-3.

[0033]

[Table 3]

Example 3 Example 1 was repeated except that another halocyanoamide derivative was used as the halocyanoacetamide derivative instead of DBNPA, a cationic polymer was used, and each was individually added.
The sterilizing power test was conducted in the same manner as in. The results are shown in Table-4.

[0035]

[Table 4] However, in the table, MBNPA ・ ・ ・ Monobromocyanoacetamide DCNPA ・ ・ ・ Dichlorocyanoacetamide

Comparative Example 1 In the same manner as in Example 1, a bactericidal activity test was carried out on the halocyanoacetamide derivative alone or the cationic polymer alone. The results are shown in Table-5.

[0037]

[Table 5]

[0038]

Industrial Applicability As is apparent from the above, the present invention can be expected from the independent use of the halocyanoacetamide derivative and the cationic polymer in the sterilization of Legionella bacteria which occur in the cooling water system. It has an extremely excellent effect that cannot be achieved, has no corrosiveness to metals, is highly safe, and has excellent economical efficiency, and is industrially useful.

Claims (2)

[Claims] 1. A disinfecting water treatment agent comprising a halocyanoacetamide derivative represented by the general formula (1) and a cationic polymer represented by the general formula (2) or (3) as active ingredients. [Chemical 1] (In the formula, X is a halogen atom, Y is a halogen atom or a hydrogen atom, and R ¹ is a hydrogen atom or a lower alkyl group.) 2. The water treatment agent according to claim 1, wherein the halocyanoacetamide derivative represented by the general formula (1) is dibromoacetamide.