JP2002001352A - Slime deposition prevention method for water system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively prevent slime from being deposited on a water system with a low concentration of a sterilizing agent. SOLUTION: In this method, the slime is prevented from being deposited on the water system to be treated by adding maleimide into the water system so that its concentration in the water is less than sterilization concentration.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preventing slime from adhering to water, and more particularly, to a water system for cooling, a metal working liquid system, and a water system for papermaking (water for papermaking process, coating liquid for paper, latex, paste, etc.). ) And industrial water systems including textile manufacturing water systems, recreational water systems including swimming pools, fountains, appreciation ponds and appreciation running water systems, toilet water systems, storage tank water systems, septic tank water systems and sewage treatment water systems. The present invention relates to a method for effectively preventing slime from adhering to a member surface in contact with water in various water systems such as water systems for sanitary facilities including a small amount of chemicals.

[0002]

2. Description of the Related Art In an industrial water system such as a cooling water system or a papermaking water system, microorganisms adhere to and grow on a tube wall or a vessel wall while generating a viscous substance, forming slime. When such slime is generated, for example, in a cooling water system,
This causes problems such as a decrease in heat exchange efficiency, corrosion of the piping surface, and blockage in the piping system. In a papermaking water system, slime adhered to a wall surface falls off and causes product defects such as paper breakage and spots.

As a means for solving such a problem, conventionally, a chemical substance (biocide) is added at a concentration sufficient to kill microorganisms in an aqueous system or to suppress the growth thereof. I have.

[0004] For example, Japanese Patent Application Laid-Open No. 2000-63209 discloses a method for sterilizing or inhibiting the growth (antibacterial) of microorganisms present in a dispersed state in water (hereinafter sometimes referred to as “dispersed bacteria”). A first component comprising a maleimide,
It describes that a second component comprising another bactericide is used in combination.

[0005]

However, in order to prevent the adhesion of water-based slime, it is necessary to add a bactericide to the water system to such an extent that microorganisms can be sterilized or their growth can be suppressed. It is industrially disadvantageous because the concentration is high and not only drug cost but also adverse effects on the environment are feared.

[0006] Japanese Patent Application Laid-Open No. 2000-63209 also aims to obtain a bactericidal or antibacterial action of dispersing bacteria. Therefore, according to the method described in the same patent, when maleimide alone is added, the addition concentration is 2 mg / ml. It is considered that a bactericidal effect cannot be obtained with L or so, and it is necessary to add maleimide at a high concentration, and it is necessary to use another bactericide in a concentration higher than the concentration at which a synergistic effect is obtained.

[0007] It is an object of the present invention to solve the above-mentioned conventional problems and to provide a method for effectively preventing the adhesion of slime to an aqueous system using a low concentration of a bactericide.

[0008]

The method for preventing slime from adhering to an aqueous system according to the present invention is characterized in that maleimide is added to an aqueous system to be treated so that the concentration of maleimide in water is lower than the concentration at which maleimide exhibits a bactericidal effect. And

That is, the present inventors have conducted intensive studies to achieve the above object, and as a result, it has been found that maleimide exhibits an effect of preventing slime adhesion even in a low concentration region in which maleimide does not exhibit a bactericidal effect. As a result, it has been found that a sufficient effect can be obtained by adding such a low concentration, and the present invention has been completed.

It is a characteristic of maleimide that maleimide exhibits an effect of sufficiently preventing slime from adhering to the surface of a member in contact with an aqueous system even at such a low concentration that it does not exhibit a bactericidal effect against dispersed bacteria. Yes, for example, DBNPA (2,
Unless 2-dibromo-3-nitrilopropionamide is added at a concentration that exhibits a bactericidal effect, slime adhesion cannot be prevented. In addition to DBNPA, generally, in order to prevent slime from adhering, it is necessary to add a high concentration so as to exhibit a bactericidal effect, as described in JP-A-2000-63209.
The publication also does not suggest that slime can be prevented from sticking with a low concentration of maleimide that does not exhibit a bactericidal effect.

The details of the effect of maleimide, which does not show a bactericidal effect at a low concentration, which effectively prevent slime from adhering, are not clear. It is considered that the adhesion of the viscous substance to be performed can be prevented, and thereby the slime adhesion failure can be effectively prevented.

In the present invention, the addition concentration of maleimide is particularly preferably 0.1 mg / L or more and less than 20 mg / L.

[0013]

Embodiments of the present invention will be described below in detail.

In the present invention, maleimide is added to the aqueous system to be treated at a low concentration less than the concentration at which maleimide exhibits a bactericidal effect, preferably 0.1 mg / L to 20 mg / L.
L, more preferably 1 mg / L or more and less than 20 mg / L, particularly 1 to 10 mg / L. Even if maleimide is added at a concentration of 20 mg / L or more, a decrease in the number of bacteria in the aqueous system is observed, but there is no difference in the effect of preventing slime adhesion, which is disadvantageous in terms of drug cost and the like. The lower limit of the amount of maleimide added, that is, the minimum concentration at which maleimide exhibits an effect of preventing slime adhesion, varies depending on the water quality of the water system to be treated, operating conditions, and the like, but this concentration can be easily determined by preliminary experiments and the like.

The maleimide used in the present invention may be either a solid drug or a liquid preparation, and therefore may be a composition containing maleimide.

In the case of a liquid preparation, the form can be used as a solution, dispersion, emulsion, suspension or paste. As the solvent, water or a hydrophilic solvent is preferable. Examples of the hydrophilic solvent include, but are not limited to, alcohols, glycols, amides, glycol esters, esters, and the like.

When used as a composition, in addition to the maleimide, other antibacterial agents, corrosion inhibitors, scale inhibitors, defoamers, surfactants, antialgal agents, pH adjusters and the like may be used, if necessary. Can be blended.

As the antibacterial agent, for example, esters of halogenated aliphatic nitro compounds such as isothiazolone compounds, 2-bromo-2-nitro-1,3-propanediol and 2-2-dibromo-2-nitroethanol , Dibromonitropropionamide, alkylenebisthiocyanate such as methylenebisthiocyanate, 1,4-bisbromoacetoxy-2-butene, hexabromodimethylsulfone, 5-chloro-2,4,6-trifluoroisophthalonitrile, tetrachloro Isophthalonitrile-based compounds such as isophthalonitrile, dimethyldithiocarbamate, 4,5-dichloro-1,2-diol-3-
On, 3,3,4,4-tetrachlorotetrahydrothiophene-1,1-dioxide, triiodoallyl alcohol, bromonitrostyrene, glutaraldehyde,
Aldehyde compounds such as phthalaldehyde, isophthalaldehyde, terephthalaldehyde, dichloroglyoxime, α-chlorobenzaldoxime acetate, α
And benzaldoxime compounds such as -chlorobenzaldoxime and 5,5-methylhydantoin.

As the corrosion inhibitor, for example, tolyltriazole, benzotriazole, methylbenzotriazole, molybdic acid, tungstic acid, silicic acid, nitrous acid, 2-phosphonobutane-1,2,4-tricarboxylic acid, hydroxyethylidene diphosphone Examples thereof include acids, hexametaphosphoric acid, tripolyphosphoric acid, orthophosphoric acid and salts thereof, zinc chloride, zinc chloride hydrochloride, zinc sulfate, zinc ligninsulfonate, hydrazine and the like.

As the scale inhibitor, for example, polyacrylic acid, copolymer of acrylic acid / 2-hydroxyethyl methacrylate, copolymer of acrylic acid / 2-hydroxyethyl methacrylate / methyl acrylate, acrylic acid / allyl glucidyl Ether copolymer, acrylic acid / 2-hydroxy-3-allyloxy-1-propanesulfonic acid copolymer, acrylic acid / isoprenesulfonic acid copolymer, acrylic acid / vinylsulfonic acid copolymer, acrylic Acid / allylsulfonic acid copolymer, polymaleic acid, maleic acid or maleic anhydride / isobutylene copolymer, maleic acid or maleic anhydride / styrenesulfonic acid copolymer, maleic acid or maleic anhydride / acrylic acid Copolymer of maleic acid or maleic anhydride / methacrylic acid Acid copolymer, maleic acid or maleic anhydride / 2-acrylamido-2-methylpropanesulfonic acid copolymer, maleic acid or maleic anhydride / amylene acid copolymer, maleic acid or maleic anhydride / allyl And a copolymer of a fluorinated fluorescent substance (such as 5-allylbenzosuberenol), polyacrylamide, polyitaconic acid, and salts thereof.

Examples of the antifoaming agent include silicone or non-silicone antifoaming agents, examples of surfactants include anionic, cationic, nonionic and amphoteric surfactants, and examples of antialgal agents include And, for example, amethrin.

Examples of the pH adjuster include hydrochloric acid, sulfuric acid, sodium hydroxide, potassium hydroxide and the like.

In the method of the present invention, except that maleimide is added at a low concentration as described above, chemical injection control can be performed in accordance with a conventional method, such as addition to an aqueous system, continuous injection or intermittent injection. Is not particularly limited.

The aqueous system to be treated in the method of the present invention is not particularly limited, and the present invention relates to a cooling aqueous system, a metal working liquid system, a papermaking aqueous system (papermaking process water, paper coating liquid, latex, Water for industrial use including water systems for fabric production, etc., recreational water systems including swimming pools, fountains, appreciation ponds and running water systems for appreciation, water systems for toilets, water systems for reservoirs, water systems for septic tanks and sewage. It is possible to effectively prevent slime from adhering to a member surface in contact with water in a wide range of water systems such as a water system for sanitary facilities including a water system for treatment.
Here, the member that comes into contact with the water is a member that at least partially contacts the water of the aqueous system continuously or intermittently, and is not particularly limited, and is a member that is immersed in water and comes into contact with the water flow. Examples thereof include a member and a member that is wet with water, and the material may be any of a hydrophobic material and a hydrophilic material. Specific examples include, but are not limited to, metal and concrete surfaces such as inside pumps, pipes, cooling towers, and heat exchangers.

[0025]

The present invention will be described more specifically with reference to the following examples.

Example 1 Maleimide was added to a mixed bacterial culture cultivated in a PY medium (5 mg-BOD / L) so as to have a concentration shown in Table 1, and the mixture was passed through a silicon tube having an inner diameter of 3 mm at 30 ° C. Water was passed at a water speed of 5.5 m / sec, and the amount of slime attached after 3 days was measured. The measurement of the amount of slime adhered was performed by scraping slime adhered to the inner surface per 30 cm of the silicon tube, centrifuging, and measuring the wet capacity. Based on the result of the wet capacity, a slime adhesion ratio (vs. blank) at each concentration was determined. In addition, the number of surviving bacteria of the dispersed bacteria in the liquid was measured. Table 1 shows the results.

As the PY medium, 25.2 g of polypeptone, 25.2 g of yeast extract, 55.2 g of NaCl were added to 5 L of tap water.
A solution prepared by dissolving 12.6 g and 3.25 g of NaOH and autoclaving (120 ° C. × 15 minutes) was used.

[0028]

[Table 1]

As is clear from the results shown in Table 1, when the maleimide concentration is 0.5 mg / L or more, there is an effect of preventing slime adhesion. In particular, addition of 1 mg / L or more completely suppresses slime adhesion. Can be. Among them, No. 10 having an addition concentration of 20 mg / L or less was used. In Nos. 3 to 9, the number of surviving bacteria was blank No. 3; There was no difference from 1 and no bactericidal effect was obtained. Therefore, from this result, it can be seen that in the range of 0.5 to 20 mg / L, slime is prevented from adhering, although no bactericidal effect by maleimide is observed.

[0030]

As described above in detail, according to the method for preventing slime from adhering to an aqueous system according to the present invention, it is possible to use a low-concentration drug, thus reducing the cost of the drug and preventing adverse effects on the environment. It is possible to effectively prevent slime adhesion failure in various water systems.

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[Procedure amendment]

[Submission date] August 21, 2001 (2001.8.2
1)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0026

[Correction method] Change

[Correction contents]

Example 1 Maleimide was added to a mixed bacterial culture cultivated in a PY medium (5 mg-BOD / L) so as to have a concentration shown in Table 1, and the mixture was passed through a silicon tube having an inner diameter of 3 mm at 30 ° C. and passing water with water rate 5.5 c m / sec, to measure the slime adhesion amount after 3 days. The measurement of the amount of slime adhered was performed by scraping slime adhered to the inner surface per 30 cm of the silicon tube, centrifuging the slime, and measuring the wet capacity. Based on the result of the wet capacity, the slime adhesion ratio (vs. blank) at each concentration was determined. In addition, the number of surviving bacteria of the dispersed bacteria in the liquid was measured. Table 1 shows the results.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C02F 1/50 540 C02F 1/50 540C A01N 37/32 101 A01N 37/32 101

Claims (2)

[Claims] 1. A method for preventing adhesion of slime by adding maleimide to an aqueous system to be treated, wherein maleimide is added so that the concentration of maleimide in water is lower than the concentration at which maleimide exhibits a bactericidal effect. Water-based slime prevention method. 2. The method according to claim 1, wherein the maleimide is added so that the maleimide concentration in the water is 0.1 mg / L or more and less than 20 mg / L.