CN111978932B

CN111978932B - Organic corrosion inhibition cooling liquid and preparation method thereof

Info

Publication number: CN111978932B
Application number: CN202010657816.7A
Authority: CN
Inventors: 刘雨修; 陈宏春; 王丽丽
Original assignee: Tapoa Technology Co ltd
Current assignee: Tapoa Technology Co ltd
Priority date: 2020-07-09
Filing date: 2020-07-09
Publication date: 2022-02-01
Anticipated expiration: 2040-07-09
Also published as: CN111978932A

Abstract

The invention relates to an organic corrosion inhibition cooling liquid and a preparation method thereof, wherein the organic corrosion inhibition cooling liquid comprises the following components in percentage by mass: 0.05 to 0.2 percent of methyl benzotriazole or benzotriazole; compounding a component A: 0.5 to 2 percent of caprylic acid and 0.50 to 3.0 percent of 2-ethyl caproic acid; compounding a component B: 1.0 to 2.0 percent of azelaic acid, 1.5 to 2.5 percent of terephthalic acid, 2.0 to 3.0 percent of neodecanoic acid and 0.5 to 2.0 percent of sebacic acid; 0.1 to 2.0 percent of sodium benzoate; 0.2 to 0.7 percent of polyhexamethylene guanidine; fluorescein sodium 1-10 ppm; 20-40ppm of organic silicon defoamer; the balance of water and glycol, wherein the water and the glycol are added according to the freezing point proportion. The organic corrosion inhibition cooling liquid disclosed by the invention adopts the principles of proportioning and compounding of organic acid and other organic corrosion inhibitors, synergistic effect between monoacid and dibasic acid and the like, and has the advantages of high stability, stronger corrosion resistance, less environmental pollution, long service life, more environmental and health benefits and the like.

Description

Organic corrosion inhibition cooling liquid and preparation method thereof

Technical Field

The invention relates to the field of engine cooling, in particular to an organic corrosion inhibition cooling liquid and a preparation method thereof.

Background

The total market demand of the vehicle coolant will increase with the increase of the automobile holding capacity, and the engine coolant is a heat-conducting medium in a cooling system, has the functions of cooling, corrosion prevention, scale prevention and freeze prevention, is an indispensable component for normal operation of an engine, and has higher and higher quality requirements on the automobile engine coolant along with the rapid development of the automobile industry at home and abroad in recent years. The commonly used engine coolant is mostly aqueous solution of glycol, water is the main cooling medium, and glycol is used for lowering the freezing point of the coolant; meanwhile, in order to ensure that metal parts of an engine cooling system are not corroded by cooling liquid in the using process, various corrosion inhibitors are generally added into the cooling liquid. The common corrosion inhibition additive used in the cooling liquid is mainly inorganic salt, and the traditional antifreezing liquid mostly adopts inorganic corrosion inhibitor or inorganic and organic compound corrosion inhibitor. The traditional antifreeze is mainly prepared from silicate, but the silicate has poor stability after being stored and used for a period of time, and is easy to form gel precipitate, so that the corrosion inhibition performance is reduced, and the gel is easy to block an engine pipeline in the using process and adheres to the inner surface of a radiator to reduce the heat transfer efficiency to cause the overheating fault of the engine.

Disclosure of Invention

In order to make up for the defects of the prior art, the invention provides the organic corrosion-inhibition cooling liquid which has the advantages of strong corrosion resistance, high storage stability, strong hard water resistance and the like, is long in service life, slow in consumption, long in service life and high in storage stability, and does not contain silicon, phosphorus, chlorine, molybdate, nitrite and ammonium salt which are harmful to human bodies and the environment.

The technical scheme adopted by the invention for solving the technical problems is as follows:

an organic corrosion inhibition cooling liquid comprises the following components in percentage by mass:

0.05 to 0.2 percent of methyl benzotriazole or benzotriazole; compounding a component A: 0.5 to 2 percent of caprylic acid and 0.50 to 3.0 percent of 2-ethyl caproic acid; compounding a component B: 1.0 to 2.0 percent of azelaic acid, 1.5 to 2.5 percent of terephthalic acid, 2.0 to 3.0 percent of neodecanoic acid and 0.5 to 2.0 percent of sebacic acid; 0.1 to 2.0 percent of sodium benzoate; 0.2 to 0.7 percent of polyhexamethylene guanidine; fluorescein sodium 1-10 ppm; 20-40ppm of organic silicon defoamer; the balance of water and glycol, wherein the water and the glycol are added according to the freezing point proportion.

The method for preparing the organic corrosion inhibition cooling liquid comprises the following steps:

a. adding glycol and water into a reaction kettle according to a freezing point proportion, and uniformly stirring;

b. after ethylene glycol and water are uniformly stirred, adding methylbenzotriazole, caprylic acid, azelaic acid, terephthalic acid, 2-ethylhexanoic acid, 80% polyhexamethylene guanidine, neodecanoic acid, sodium benzoate and sebacic acid according to a proportion; because the PH values of the polyhexamethylene guanidine are different due to different purities of the polyhexamethylene guanidine, only 80 percent of the total amount of the polyhexamethylene guanidine is added when the polyhexamethylene guanidine is added for the first time in order to prevent the PH value from exceeding the standard;

c. measuring the pH value, continuously adding polyhexamethylene guanidine according to the measured pH value, and adjusting the pH value to be 7.5-11.0, which meets the national standard range;

d. adding sodium fluorescein and an organic silicon defoaming agent, and uniformly stirring to obtain the organic corrosion inhibition cooling liquid.

The invention adopts the structure, and has the advantages that:

1. the organic corrosion inhibition cooling liquid disclosed by the invention adopts the principles of proportioning and compounding of organic acid and other organic corrosion inhibitors, synergistic effect between monoacid and dibasic acid and the like, and has the characteristics of high stability, stronger corrosion resistance, less environmental pollution, long service life, more environmental and health benefits and the like.

2. The organic corrosion-inhibiting cooling liquid completely eliminates the addition of inorganic salt, greatly reduces the precipitation of organic matters, eliminates silicate and ensures that the gelation phenomenon cannot occur. The action mechanism of the organic corrosion inhibition cooling liquid is different from that of a silicate cooling liquid, the inorganic corrosion inhibition cooling liquid directly reacts on the metal surface to form a film, namely, the metal surface is wrapped, and once a protective film disappears, the protective film is immediately supplemented, so that the consumption is high, the organic corrosion inhibition cooling liquid is formed by closely adsorbing organic matters on the metal surface without reacting to form a film, and the metal is completely protected by intermolecular force, so that the service life of the cooling liquid is greatly prolonged.

3. The components in the cooling liquid are coordinated and compounded, and the corrosion inhibition rate of the red copper and the brass is greatly enhanced by the added methylbenzotriazole; the added octanoic acid and 2-ethyl caproic acid enhance the corrosion inhibition rate on aluminum, and in addition, the added sodium benzoate enhances the corrosion resistance of the antifreeze; the azelaic acid, terephthalic acid, neodecanoic acid and sebacic acid in the formula have extremely strong corrosion inhibition performance on red copper, soldering tin, brass, cast steel, cast iron and cast aluminum; the cavitation corrosion of the engine is serious, so in order to enhance the cavitation corrosion resistance, an organic silicon defoaming agent is added in the formula, and the defoaming agent has stronger water solubility and long-acting property than other types; in addition, GB29743-2013Z requires the pH and the appearance of the antifreeze, so polyhexamethylene guanidine is added to adjust the pH of the antifreeze to meet the range of national standard 7.5-11.0, and the coolant has low conductivity after the polyhexamethylene guanidine is used, so that the coolant is suitable for automobiles and other high-requirement engines. The appearance was prepared by adding sodium fluorescein. The proportions of the components in the formula are coordinated with each other, the dosage of the components is completely suitable for the optimal corrosion prevention value of various metals, and the negative effect caused by overhigh concentration is effectively avoided.

Detailed Description

In order to more clearly explain the overall concept of the present application, the following detailed description is given by way of example. In the following description, specific details are given to provide a more thorough understanding of the present application. It will be apparent, however, to one skilled in the art, that the present application may be practiced without one or more of these specific details.

Raw material purity: methyl benzotriazole: not less than 99%; octanoic acid: ≧ 98%; 2-ethylhexanoic acid: ≧ 99.5%; azelaic acid: not less than 99%; terephthalic acid: not less than 97%; neodecanoic acid: not less than 99%; sebacic acid: ≧ 98%; sodium benzoate: ≧ 95%; polyhexamethylene guanidine: ≧ 99.5%; sodium fluorescein: jiangsu caragana actual Co., Ltd; and (3) organic silicon defoaming agent: guangzhou DeluVium trade, Inc.; ethylene glycol: ≧ 99.9%.

The organic corrosion inhibition cooling liquid is prepared by the following method, and specifically comprises the following steps:

b. after the ethylene glycol and the water are uniformly stirred, the components are put into and mixed according to the proportion;

wherein, the PH value is different due to different polyhexamethylene guanidine purities, so that only 80 percent of the total amount of the polyhexamethylene guanidine is added when the polyhexamethylene guanidine is added for the first time in order to prevent the PH value from exceeding the standard;

Embodiment 1 provides an organic corrosion-inhibiting cooling liquid, which comprises the following components in percentage by weight: 0.15 percent of methyl benzotriazole or benzotriazole; compounding a component A: 0.8% of caprylic acid and 2.45% of 2-ethylhexanoic acid; compounding a component B: 1.35% of azelaic acid, 1.8% of terephthalic acid, 2.5% of neodecanoic acid and 0.8% of sebacic acid; 1.2 percent of sodium benzoate; 0.7% of polyhexamethylene guanidine; fluorescein sodium 5 ppm; 25ppm of organic silicon defoamer; the balance being water and ethylene glycol. Technical indexes of the organic corrosion inhibition cooling liquid prepared in the example 1 are shown in the following table 1:

the control experiment provides an inorganic cooling liquid which comprises the following components in percentage by mass: 0.15% of benzotriazole, 0.35% of triethanolamine, 0.21% of sebacic acid, 0.15% of sodium hydroxide, 0.14% of sodium nitrate, 0.3% of sodium nitrite and 1.0% of sodium silicate, and water and glycol are added according to the proportion of freezing point. The preparation method comprises the following steps: a. adding glycol and water into a reaction kettle according to a freezing point proportion, and uniformly stirring; b. after ethylene glycol and water are uniformly stirred, adding methylbenzotriazole, triethanolamine, sebacic acid, partial sodium hydroxide, sodium nitrate, sodium nitrite and sodium silicate according to a proportion, and measuring the pH value; c. sodium hydroxide is properly added according to the measured pH value, so that the pH value meets the national standard range of 7.5-11.0. d. Adding 5ppm of fluorescein sodium and 25ppm of organic silicon defoaming agent into the prepared cooling liquid, and uniformly stirring to obtain inorganic cooling liquid, wherein the technical indexes of the inorganic cooling liquid are shown in the following table 1:

TABLE 1 technical indices of the coolants corresponding to example 1 and the control experiments

The corrosion test of the cooling liquid glassware of the motor vehicle engine is carried out according to SH/T0085-1991, and the measurement results of the example 1 and the control test are as follows, and are specifically shown in a table 2:

table 2 results of glassware corrosion test measurements on coolants of example 1 and control experiments

As can be seen from Table 2, all indexes of the cooling liquid prepared in the embodiment 1 of the invention meet the SH/T0085-91 industrial standard. Through the compounding of all the components, the corrosion-resistant paint has good corrosion-resistant effect on red copper, brass, soldering tin, cast iron, cast steel and cast aluminum, can avoid the introduction of nitrite, chromate, nitrate, phosphate, silicate or ammonium salt, and cannot cause pollution to the environment. The action mechanism of the organic corrosion inhibitor is as follows: the organic matter is closely adsorbed on the metal surface, a compact adsorption film can be formed on the metal surface, the corrosion of the metal by products formed by the decomposition or acidification of glycol in the cooling liquid is prevented, and the corrosion-resistant and anti-scaling performance is good.

All indexes of the cooling liquid prepared by contrast experiments meet the SH/T0085-91 industrial standard. The anti-corrosion antifreezing solution has the advantages that the anti-corrosion antifreezing solution has good anti-corrosion effect on six metals, namely red copper, brass, soldering tin, cast iron, cast steel and cast aluminum, the action mechanism is that a layer of oxide film is formed on the surface of the metal through reaction with the metal, so that the corrosion rate of the metal is slowed down, although the anti-corrosion antifreezing solution has good anti-corrosion performance, the concentration of various additives in the anti-corrosion antifreezing solution is gradually reduced along with consumption, and the corrosion of the metal is accelerated due to the fact that the concentration cannot meet the protection requirement in the later period.

The test results of the cast aluminum corrosion test of the cooling liquid of the motor vehicle engine are carried out according to SH/T0085-1991, and the test results of the example 1 and the control test are as follows, and are specifically shown in Table 3:

TABLE 3 results of corrosion test of cast aluminum for the cooling liquid of example 1 and the control experiment

	Cast aluminum test piece	Phenomenon(s)
			GB29743-2013	±1.0mg/cm²
Example 1	+0.2mg/cm²	Transparent, free from impurities, unchanged test piece
			Control experiment	+0.6mg/cm²	With gel, no change in test piece

As can be seen from Table 3, the protective effects of the cooling liquid prepared in example 1 and the comparative experiment on various metals all meet the national standard, but the cooling liquid in the comparative experiment has certain gelation phenomenon after being subjected to aluminum cast corrosion measurement of the engine cooling liquid, and the diffusion head of the gas diffusion tube is obviously blocked. Whereas example 1 had no gel phenomenon.

Comparative experimental examples 2-11 of example 1 were set up to further investigate the effect of the components and component ratios on the cooling fluid, as shown in table 4.

TABLE 4 compositions and percentages by mass of the coolants of examples 1 to 11

The corrosion test of the glassware of the engine coolant of a motor vehicle was carried out according to SH/T0085-1991, and the results of the measurements of examples 1 to 11 corresponding to Table 4 are as follows, in particular, see Table 5:

TABLE 5 results of glassware corrosion test measurements on coolants of examples 1-11

As can be seen from Table 4, the difference between example 2 and example 1 is that the mass percentages of the compound component A and the compound component B are increased, and polyhexamethylene guanidine as a PH regulator is adjusted accordingly; as shown in the test results in Table 5, the cooling liquid of example 2 has data that is significantly beyond the national standard, and the corrosion resistance of the six metals, namely red copper, brass, solder, cast iron, cast steel and cast aluminum, is reduced because, although a dense adsorption film is still formed on the metal surface in the early stage, and corrosion of the metal by products formed by glycol decomposition or acidification in the cooling liquid is prevented, the concentration of each acid added in the example is too high, which leads to increased corrosion of the metal in the later stage.

As can be seen from Table 4, the difference between example 3 and example 1 is that the mass percent of the compound component B is reduced, and polyhexamethylene guanidine as a PH regulator is adjusted accordingly; as shown in the test results in Table 5, the data of the cooling liquid of example 3 is over the national standard, and the corrosion resistance of the cooling liquid to the six metals of red copper, brass, solder, cast iron, cast steel and cast aluminum is reduced, because example 3 hardly forms an adsorption film on the metal surface in the initial stage, the corrosion of the metal by the products formed by the decomposition or acidification of glycol in the cooling liquid cannot be inhibited, and because of the addition of various additives, various ions and the metal form galvanic cells, which aggravates the corrosion of the metal.

As can be seen from Table 4, example 4 differs from example 1 in that 2-ethylhexanoic acid in compounding component A is replaced with 3-methylbutyric acid; the difference between the embodiment 5 and the embodiment 1 is that a 3-methylbutyric acid component is added into the compound component A; example 6 differs from example 1 in that only octanoic acid is present in the formulated component a; example 7 differs from example 1 in that only 2-ethylhexanoic acid is present in the built-up component A; the mass percentage of the compound component A in the total amount is not changed. As shown in the experimental results of the examples 4 to 7 in Table 5, the data of the cooling liquid of the examples 5 to 7 are greatly beyond the national standard, and the corrosion resistance of the cooling liquid to the red copper, the brass, the soldering tin, the cast iron, the cast steel and the cast aluminum is remarkably reduced, because the combination of the octanoic acid and the 2-ethylhexanoic acid in the compound components has a synergistic effect, and a better corrosion resistance effect is achieved. And the addition of acid with similar performance can affect the compounding effect of the acid and the acid, and further affect the corrosion resistance.

Example 8 differs from example 1 in that the neodecanoic acid in the compounded component B is replaced by 1,2, 3-methylpentanoic acid; the difference between the embodiment 9 and the embodiment 1 is that the dosage of neodecanoic acid in the compound component B is reduced, and another 1,2, 3-methylvaleric acid is added; example 10 differs from example 1 in that the neo-decanoic acid is absent from the formulated component B; example 11 differs from example 1 in that azelaic acid is absent from the formulated component B; the mass percentage of the compound component B in the total amount is unchanged. As can be seen from the experimental results of examples 8 to 11 in Table 5, the data of the cooling liquid of examples 8 to 11 tested are seriously beyond the national standard, and the corrosion resistance of the cooling liquid to red copper, brass, soldering tin, cast iron, cast steel and cast aluminum is remarkably reduced, because the combination of azelaic acid, terephthalic acid, neodecanoic acid and sebacic acid in the compound component B according to a certain proportion has a synergistic effect, and a better corrosion resistance effect is achieved after the compound. The addition of acid with similar performance or acid replacement can affect the compounding effect of each component and the corrosion resistance.

The cast aluminum corrosion test of the cooling liquid of the motor vehicle engine is carried out according to SH/T0085-1991, and the measurement results of examples 1-11 are as follows, and are specifically shown in Table 6:

TABLE 6 results of corrosion test for cast aluminum using the cooling liquids of examples 1 to 11

As can be seen from the test results in Table 6, the cooling liquid of example 1 has no corrosion and no change in the cast aluminum test piece when tested in the cast aluminum corrosion test; the coolants of examples 2 to 11, on the other hand, all showed corrosion after the corrosion test in cast aluminum, and the test pieces tended to turn black or black, except for examples 5 and 9.

As can be seen from the experimental results in tables 5 and 6, the cooling liquid obtained by mutually coordinating and compounding the components has a good anti-corrosion effect.

The above-described embodiments should not be construed as limiting the scope of the invention, and any alternative modifications or alterations to the embodiments of the present invention will be apparent to those skilled in the art. The details of the present invention are not described in detail, but are known to those skilled in the art.

Claims

1. The organic corrosion inhibition cooling liquid is characterized by comprising the following components in percentage by mass:

0.15 percent of methyl benzotriazole or benzotriazole;

compounding a component A: 0.8% of caprylic acid and 2.45% of 2-ethylhexanoic acid;

compounding a component B: 1.35% of azelaic acid, 1.8% of terephthalic acid, 2.5% of neodecanoic acid and 0.8% of sebacic acid;

1.2 percent of sodium benzoate;

0.7% of polyhexamethylene guanidine;

fluorescein sodium 5 ppm;

25ppm of organic silicon defoamer;

the balance of water and glycol, wherein the water and the glycol are added according to the freezing point proportion.

2. The method of claim 1, comprising the steps of:

b. after ethylene glycol and water are uniformly stirred, adding methylbenzotriazole, caprylic acid, azelaic acid, terephthalic acid, 2-ethylhexanoic acid, 80% polyhexamethylene guanidine, neodecanoic acid, sodium benzoate and sebacic acid according to a proportion;

c. measuring the pH value, and continuously adding polyhexamethylene guanidine according to the measured pH value to adjust the pH value to be between 7.5 and 11.0;