JPS6086286A - Water treating chemical agent - Google Patents

Abstract

PURPOSE:To provide a water treating chemical agent having an excellent corrosion inhibiting action of a metal, obtained by together using aliphatic oxycarboxylic acid or a salt thereof, benzotriazoles and alkali metal silicate. CONSTITUTION:A water treating chemical agent contains aliphatic oxycarboxylic acid or a salt thereof, benzotriazoles, alkali metal silicate and, if necessary, polyacrylic acid or a salt thereof. By adding this chemical agent to a recirculating cooling water passing system so as to bring the amount of the total chemically effective component to about 20-500ppm, the metal wall surface contacted with water is effectively protected from corrosion and adhesion of scale and other suspended substances.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to water treatment agents for the protection of metals in contact with water. More specifically, metal walls in contact with water in circulating cooling water systems, hot water systems, and other water circulation systems are corroded.
The present invention relates to water treatment agents for protecting against adhesion of scale and other suspended matter.

Any water system can be dangerous if the water pipe material is not corrosion resistant and is not protected against corrosion. In a circulating cooling water system such as an air conditioning system, the cooling water is circulated and reused, and it is also a general management method to suppress the amount of blow water, resulting in concentration of the cooling water and an increase in salt concentration. As a result, scale and suspended solids are deposited on the wall surface, and corrosion of the metal is increased due to this, and scale damage and corrosion damage are likely to occur. Scale and the like that adhere to the heat conductive surfaces of equipment heat exchangers and the like may cause a decrease in heat exchange efficiency and may lead to cracking or high pressure cuts. Rust lumps in pipes may cause blockages and water leaks.

The present inventors have developed a salt of an aliphatic oxycarboxylic acid or a salt thereof,
It has been found that by using benzotriazoles and alkali silicates in combination, an extremely excellent anticorrosion effect can be obtained. Furthermore, it has been found that when polyacrylic acid or its salt is used in combination with these, the anticorrosion effect is further enhanced.

The present invention provides a patented drug characterized by containing an aliphatic oxycarboxylic acid or a salt thereof, a benzotriazole, and an alkali salt of thiic acid, and a patented drug which further contains polyacrylic acid or a salt thereof. Regarding water treatment chemicals.

The aliphatic oxycarboxylic acid or its salt used in the present invention is water-soluble and is known to be used as a -Fi, anti-corrosion agent for metals due to its chelating action. Examples include gluconic acid, citric acid, malic acid, tartaric acid, lactic acid, and glycolic acid as representative examples. Good examples of salts include sodium salts and potassium salts. It is known that the anticorrosion effect of these oxycarboxylic acids alone is not strong enough to be used for practical purposes.

Typical incitriazoles that can be used in the present invention have the general formula (I): (wherein,
These are water-soluble compounds represented by the following formula (indicating an alkali metal), and are known as anticorrosive agents for copper-based metals. However, these do not have the anticorrosion effect of iron.

Typical examples of the compounds represented by Itoki General 2〇) include the following (including their alkali metal salts): IH-benzotriazole, 4-methyl to IH-benzotriazole, 5 -Methyl-IH-benzotriazole, 4-carboxy-IH-benzotriazole, 4-
Butoxycarbonyl-IH-benzotriazole Examples of alkali metal salts thereof include sodium salt and potassium salt.

Examples of the alkali silicate salts that can be used in the present invention include sodium silicate, sodium metasilicate, potassium silicate, and the like. The vipers include those that have an average molecular weight of 20, nn0N degrees or less and are water-soluble or have the property of easily dispersing in water and exhibiting vine properties (including those that can be dispersed and vine with the aid of adjuvants). can be mentioned. A typical example is sodium polyacrylate. Although such polymers are known to have a calcium carbonate scale dispersion effect (scale adhesion inhibiting effect), this effect is weak and they are rarely used alone.

According to the present invention, iron-based 71-arsenic metal is added to the water receiving part by using the above-mentioned fatty acid ff/J group mexicarboxylic acid, benzotriazole, and alkali silicate. Excellent effects can be obtained in preventing corrosion, scaling, and adhesion of suspended matter in the water flow system used. According to the present invention, the anti-corrosion effect is further stabilized and enhanced by further adding polyacrylic acid or a salt thereof to the above-mentioned components. In a typical formulation for the present invention, rL1 each of the above-mentioned components is used in the form of water-soluble or ice-water dispersible crystals, so in this case,! The composition of the invention can be provided in the form of a solution or in the form of a powder or powder in a size convenient for use. , 5 to 30% (weight ratio) of aliphatic oxycarboxylic acid or its salt.

(same below), benzotriazoles in 1 to 10%, and alkali silicate in 5 to 30%. However, when forming an aqueous solution, it is necessary to dissolve it in water as a solvent and to form an aqueous solution. It goes without saying that the choice must be made from within the range in which the product can be obtained. The blending ratio of polyacrylic acid or its salt is 5 to 3 in the product.
You can choose from a range of 0%.

In the water treatment agent of the present invention, the total amount of the medicinal ingredients of the present agent in the water system is usually approximately 20 to 500 ppm, preferably 40 ppm.
It is added to the water flow system to be treated so that it becomes ~J1111 ppm. In order to ensure the effectiveness, and in high-temperature water flow systems where the water temperature is around 500C or more frequently, it is convenient to use a high y-fluidity within the above 4 degree range. For example, the total amount of medicinal ingredients. as 50~5nO
It is desirable to use a similar material in the ppm range ○ Experimental Example 1 Cutting Steel Test Piece Standard 88-. 41 Size: 50 mm x 30 mm x 1 mm, with a hole 3 mm in diameter at the top. 31.6 cm2 Pretreatment The mild steel pieces were pretreated by a conventional method. In other words, IM-N was immersed in petroleum benzine for one length a day to be humiliated.
Soaked in aOH for 9000 min, rinsed with distilled water,
30 crab in HO1 for 1 minute, 20% in vessel 03 for 20 seconds,
After immersing for 1 minute in 30% HO1, wash with distilled water and methanol in that order, dry, weigh accurately, and test.

Practical method: Add the test chemical to Osaka city water at a predetermined temperature of 4 degrees, make the overall view 51111 rr+l, and keep the water at the predetermined temperature. A pretreated @structure test piece was coated with a piano wire covered with Cassie paint. It was suspended and immersed in the solution described above.

Stir the 7R liquid with a stirrer, 4 (111 rpm),
In addition, water that evaporated during the test period was replenished with Osaka city water as appropriate. Corrosion products on the test piece are removed by brushing and then immersed in a 1% HC/solution containing 1% propargyl alcohol as an inhibitor. The test piece was weighed and the corrosion rate and corrosion protection rate were calculated. The results are shown in the table below.

△W: Weight loss before and after test (mg) S: Area (4m2) J): Between ears (days) Conditions Water temperature 25°C ± 0.200 Immersion time 48 hours Osaka city water analysis value MS: Sodium metasilicate BT :IH-Benzotriazole Experimental Example 2 For water treatment agent of Example 1+lI2 formulation (1) Liquid temperature 5±
Actual shot example 1 at 0.02°C and (2+42” 0.5°C)
A corrosion inhibition effect test was conducted according to the method described in . The results are shown in the table below. Note that the concentration (ppm) in the table is the maximum concentration (ppm).

1) When the liquid temperature is (1) 2) When the liquid temperature is (2) Experimental example 3 Corrosion inhibition effect according to the method of Experimental example 1 at liquid drying ratio ±0.200 for the water treatment agent prescribed in Example 3 I passed the exam. The results are shown in the following table.
is 4 degrees (ppm) as a formulation.

Experimental Example 4 Using the water treatment agent formulated in Example 3, an on-site experiment was conducted on the corrosion inhibiting effect in the Hayabusa Building heat storage tank. N quality SS-, 4
The mild steel test piece of No. 1 was dipped in two places with a hanging string. Other procedures followed the methods of Example 1 and Example 1.

Conditions Amount of water held in the building heat storage tank Approximately 40 tons Water temperature 55
~60°C Experimental heat 121 days G1g agent addition fd 2A) kg (H so 500p pm
) Water chromaticity 12 pH8,6 (2000) (0/-':l 26.' my/ /IC8od 1
47.8mg// Iron 0.11 mg/l Copper 0.02mg/IJ Zinc 0.02mg/1 (Si02) 192mg/l Total alkalinity 71.8 mg/l Total hardness 111 mg#' Electrical conductivity 396 μ/ cm The results are shown in the table below. In addition, 4 degrees (ppm) in the table is the concentration as a drug (ppm).

Reference Example According to the method of Milling Example 1, the anticorrosion properties of the chemicals listed in the table were investigated.

Conditions: ±0.580 Soaking time: 240 hours Next, some actual chewing examples will be shown, but it goes without saying that the quality and proportion of the ingredients can be changed within the scope of the present invention.

'ρ1 Width Example 1 Polyacrylic Sodium (J1%Wo Kayacrylic Resin H
-35N) 2F 1% Sodium metasilicate 5% Sodium gluconate 5% 1) A water treatment agent prepared by uniformly dissolving 1% 4-benzotriazole in 69% water.

This treatment agent is used to prevent corrosion of metals in cold 711A water systems.

Mizuya Example 2 Polyacrylic Soda (40%) Kayacrylic Resin I
A water treatment agent made by uniformly dissolving 20% sodium silica vinegar 10% 0% sodium gluconate 5% 114-benzotriazole 1% in 64% water.

This water treatment agent is used to prevent corrosion of metals in cold Δ and λ water systems [(−
used for.

Actual I fabric example 3 Polyacrylic 4 soda (40% product Kayacrylic resin ■ (-
3FN) 2I)% Sodium metasilicate 5% Sodium gluconate 10I 11-T-benzotriazole 1I A water treatment agent prepared by uniformly dissolving 1I in 64% water.

Claims (1)

[Claims] (1) A water treatment agent characterized by containing an aliphatic oxycarboxylic acid or its salt, benzotriazoles and an alkali silicate salt (2) an aliphatic oxycarboxylic acid or its salt, benzotriazoles, Water treatment agent 0 characterized by containing an alkali silicate salt and polyacrylic acid or its salt