JPS60100502A - Agent for preventing adhesion of slime in water - Google Patents

Abstract

PURPOSE:To provide the titled slime-controlling agent for a cooling water system, having low toxicity and high safety in handling, containing a hydrazide compound such as carbohydrazide, etc., and exhibiting excellent effect to prevent the adhesion of slime and to disperse the slime in spite of the weak antibacterial property. CONSTITUTION:The objective agent contains one or more hydrazide compounds selected from carbohydrazide, maleic acid hydrazide and its polymer known as an oxygen scavenger for boiler, and an acrylic acid hydrazide polymer disclosed as an antiscaling agent. The molecular weight of the above polymer is 500- 50,000. The polymer is a water-soluble polymeric compound of the monomer or polymer containing the group of formula [X is H or CH3; Y is H or carboxyl; A is (meth)acrylamide or (meth)acrylic acid ester residue; l is 10-100mol%; m is 0-90mol%] as a structural unit. The agent is applied at a concentration of 0.1-1,000ppm in terms of the hydrazine compound.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a slime adhesion inhibitor for aqueous systems, and more particularly to a slime adhesion inhibitor for aqueous systems suitable for preventing slime adhesion in aqueous systems such as cooling water systems or pulp and paper manufacturing systems. .

[Prior art]

BACKGROUND ART Slime from various fungi and plants and animals adheres to water systems such as cooling water systems of various factory facilities and pulp and paper manufacturing systems, causing various problems.

For example, in a cooling water system, slime such as zooglaea bacteria, algae, and filamentous fungi adheres to the cooling water system, causing a decrease in thermal efficiency, deterioration of water flow, and induction of corrosion of metal materials.

In addition, in pulp and paper manufacturing systems, slime from bacteria, filamentous fungi, yeast, etc. is mainly generated during the papermaking process, and this slime gets mixed in and adheres to the valve slurry as foreign matter, not only reducing the quality of the product but also reducing the quality of the product. , causing various problems such as paper breaks and significantly reducing production efficiency. especially,
In recent years, in pulp and paper manufacturing systems, there has been a tendency to increase the concentration of circulating water, and the problem caused by slime has become more serious.

In addition, organisms such as seawater algae, seawater bacteria, mussels, and sea squirts adhere to the inside surfaces of the cooling water intakes and cooling pipes of thermal power plants, steel mills, and other factories that use seawater. It causes functional decline. In addition, these attached organisms are stripped off by water pressure, flow velocity, etc., and cause clogging of other parts such as heat exchanger tubes and strainers, which obstructs the flow of seawater and reduces the functionality of the entire facility.

Conventionally, in order to prevent problems caused by such slime, methylene bisthiocyanate, hydrazine, tareoshi, and
In seawater cooling water systems, chemicals such as chlorine agents, organic tin compounds, and dithiocarbamate compounds are used.

By the way, slime adhesion is caused by fungal slime produced by slime. Therefore, in order to prevent slime adhesion, methods such as (1) killing the fungal bodies, (2) preventing the production of mucilaginous substances, and (2) denaturing the mucilaginous substances to eliminate their adhesion properties can be considered.

Conventionally used chlorine agents kill the bacteria present in the water system, so if fungal slime has already been produced when the chlorine agent is added, the adhesion may occur during circulation. This could not be avoided, and it was not possible to sufficiently prevent slime adhesion. Moreover, the drugs proposed so far are compounds with strong antibacterial or bactericidal effects such as killing microorganisms. Therefore, since it is thought that it may have an effect on other living organisms such as the human body, there is a desire for a slime adhesion preventing agent that is highly effective in preventing slime adhesion and is highly safe.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to be able to extremely effectively prevent slime adhesion, to disperse slime, and to be able to prevent slime adhesion from existing slime adhesion prevention agents. It is an object of the present invention to provide a slime adhesion preventive agent for aqueous systems, which has low toxicity and high handling safety.

[Structure of the invention]

As a result of intensive studies to achieve this objective, the present inventors found that a specific hydrazide compound or its water-soluble polymer has an extremely good slime adhesion prevention effect and slime dispersion effect despite its weak antibacterial properties. They discovered this and arrived at the present invention.

That is, the present invention provides an aqueous slime adhesion inhibitor characterized by containing at least one hydrazide compound selected from the group consisting of carbohydrazide, maleic hydrazide, luic acid hydrazide polymer, and acrylic acid hydrazide polymer. The gist of this paper is as follows.

Among the compounds related to the slime adhesion preventive agent of the present invention, carbohydrazide is known as an oxygen scavenger for boilers (USP 4,269,717), but is completely unknown as an aqueous slime adhesion preventive agent. It has not been done. Furthermore, although polyacrylic acid hydrazide has been disclosed as a scale inhibitor (Japanese Unexamined Patent Publication No. 54-94482), it is a high molecular weight polymer with a molecular weight of 700,000 to 1,000,000, and it is completely unknown that it has the effect of preventing slime adhesion. It has not been done.

The present invention will be explained in detail below.

The slime adhesion inhibitor of the present invention contains at least one hydrazide compound selected from the group consisting of carbohydrazide, maleic hydrazide, maleic hydrazide polymer, and carboxylic acid hydrazide polymer.

As the maleic acid hydrazide polymer and the acrylic acid hydrazide polymer, a water-soluble polymer compound of a monomer or copolymer containing maleic acid hydrazide or acrylic acid hydrazide as a structural unit, specifically, a polymer of a compound represented by the following formula 1 is used. Can be mentioned.

In the above formula, or hydrogen atom or methyl group, Y is hydrogen atom or carboxyl group, A is acrylamide, methacrylamide, acrylic ester or methacrylic ester, l is 10 to 100 molti, m is θ to 90 molti Each is represented.

In addition, as the polymer of the present invention, in the above formula 1, Zarani A
It is also possible to use a terpolymer obtained by polymerizing the structural unit B that can be copolymerized with. Structural unit B specifically includes vinyl sulfonic acid, allyl sulfonic acid, styrene sulfonic acid, acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, cinnamic acid, vinylbenzoic acid, and acrylonitrile. Examples include monomers such as , styrene, and vinyl acetate.

These polymers can be easily produced by conventionally known methods. For example, when producing an acrylic acid hydrazide polymer, after synthesizing polyacrylamide by a known method, an aqueous hydrazine hydrate solution is added and the temperature is raised to 50 to 90°C.
It can be obtained by reacting under the temperature conditions of If necessary, the component represented by B may be copolymerized with acrylamide to obtain a terpolymer.

In the present invention, the molecular weight of these polymers is from 500 to
It is preferably in the range of 50,000, particularly about 500 to 1oooo.

The concentration of the slime adhesion inhibitor of the present invention is hydrazide compound concentration, 0.1 to 1100 OpI), particularly 1 to 1
00 PI)m is appropriate. In this concentration range, when the concentration used is low, the slime adhesion preventive agent of the present invention has the effect of preventing the formation of mucus and the effect of denaturing the mucus to eliminate adhesion. In the case of high concentration, the effect of killing bacteria itself is added, effectively preventing slime adhesion.

The excellent slime adhesion prevention effect of the slime adhesion prevention agent of the present invention is achieved by adsorbing and acting on slime slime substances such as microorganisms and reducing the viscosity of the slime substance.
This is done by dispersing the slime and preventing it from sticking. Therefore, although the antibacterial property is low, the slime adhesion prevention effect is extremely high.

The slime adhesion inhibitor of the present invention may be used by using the above-mentioned hydrazide compound alone or by blending other additives.

[Embodiments of the invention]

The present invention will be explained in more detail by examples below.
The present invention is not limited to the following examples without exceeding its gist.

Example l Sewage coagulation and sedimentation treated water 100A! The flow rate is 20α/see
Water circulation channel (width 5cWL, depth 5ctn)
), the slime adhesion prevention effect of the compound according to the present invention was investigated.

After adding the compound according to the present invention in the amount shown in Table 1 to the waterway, the synthetic rubber plate was immersed in the treated water of the waterway for 5 days, and the dry weight of the slime adhering to the plate surface was measured.

The results are shown in Table 1.

Comparative Example 1 The weight of the adhered slime was measured in the same manner as in Example 1 except that no chemicals were added. Results Table 1 From Table 1, it is recognized that the compound according to the trap of the present invention has an excellent slime adhesion prevention effect in freshwater systems.

Example 2 Using a model waterway 1 as shown in FIG. 1, the effect of each compound on preventing the adhesion of slime such as sea breath adhering organisms was investigated.

In FIG. 1, 2 is a submersible pump that supplies seawater to the model waterway 1. 3 is a drug tank, and the stored drugs are supplied to the model waterway 1 by a chemical pump (not shown). Note that 4 is a branch header.

The model waterway 1 has a length of 2.5 (IrL width x 8 cIIL depth x 1 m), a flow rate of seawater passing through it x ojy minutes, and a flow rate of 8 (iIL/sec).

A 5USIJ adhesion plate was immersed in this model waterway, seawater was passed through it, and the chemicals shown in Table 2 were injected from the chemical tank 3 at the rate shown in Table 2 using a chemical pump. The amount of bacterial slime, algae, mussels, and Fujibbo was observed.

The results are shown in Table 2.

Comparative Example 2 The amount of adhered slime was measured in the same manner as in Example 2, except that no chemicals were added. The results are shown in Table 2.

Table 2 In Table 2, + indicates the following 5-level evaluation based on visual and microscopic observation.

++ Very much adhesion +1000 A lot of adhesion ++ Somewhat much adhesion 10 Slight adhesion - No adhesion According to Table 2, it is recognized that the compound according to the present invention has an excellent slime adhesion prevention effect even in seawater systems.

Example 3 To a 1-inch suspension of pulp slurry, 1 inch of calcium carbonate (average particle size 10 μm) was added to the pulp slurry, and a bacterial suspension consisting of paper pulp-generated slime cultured bacteria was added as a microbial component. (average particle size: 3 μm) was added to the pulp slurry.

To this, the compound according to the present invention was added in the proportions shown in Table 3,
The mixture was stirred at 30° C. and 300 rpm for 24 hours, and the average particle size in water was measured using a centrifugal sedimentation particle size distribution analyzer, and the rate of increase in the particle size was determined from the initial average particle size (10 μ).

The results are shown in Table 3.

Comparative Example 3 Polymaleic acid (molecular weight 5
ooo), polyacrylic acid (molecular weight 2000), Table 3
The particle size magnification was determined in the same manner as in Example 3, except that the proportions shown were added.

The results are shown in Table 3.

Comparative Example 4 Particle size magnification was determined in the same manner as in Example 3, except that no drug was added. The results are shown in Table 3.

Table 3 According to Table 3, it can be seen that polyacrylic acid or polymaleic acid has a slight dispersion effect on slurry, and the compounds according to the present invention have a better dispersion effect than these. This is considered to be because the compound according to the present invention disperses not only calcium carbonate but also microorganisms. Therefore, it is clear that the slime adhesion prevention agent of the present invention can reliably prevent slime adhesion even in paper pulp manufacturing systems due to its excellent dispersion effect.

〔Effect of the invention〕

As detailed above, the slime adhesion inhibitor of the present invention contains at least one hydrazide compound selected from the group consisting of carbohydrazide, maleic hydrazide, maleic hydrazide polymer, and acrylic hydrazide polymer. It exhibits extremely good slime adhesion prevention effect and slime dispersion effect in various water systems such as freshwater systems, seawater systems, cooling water systems, and paper pulp manufacturing systems.
Various slime problems that have been a problem in the past can be prevented.

Moreover, the anti-slime adhesion agent of the present invention has extremely weak antibacterial activity and therefore has low toxicity, does not cause environmental pollution, and is highly safe to handle.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view schematically showing a seawater-flow model waterway used in Example 2 of the present invention and Comparative Example 2. l...model waterway, 2...submersible pump, 3...
drug tank. Agent Patent Attorney Tsuyoshi Shigeno

Claims (6)

[Claims] (1) An aqueous slime adhesion inhibitor characterized by containing at least one hydrazide compound selected from the group consisting of carbohydrazide, maleic hydrazide, maleic hydrazide polymer, and acrylic hydrazide polymer. (2) The inhibitor according to claim 1, wherein the water system is a cooling water system. (3) The inhibitor according to claim 1, wherein the aqueous system is a paper valve manufacturing system. (4) The inhibitor according to claim 2, wherein the hydrazide compound is a carbohydrazide. (5) The inhibitor according to claim 3, wherein the hydrazide compound is a maleic hydrazide polymer and/or an acrylic hydrazide polymer. (6) The maleic acid hydrazide polymer and the acrylic acid hydrazide polymer each have a molecular weight of 500 to 5ooo. The inhibitor according to claim 5, which is characterized in that: