CN112760658B - Corrosion inhibitor for dynamic cleaning of high Wen Xiaosuan washing liquid and preparation method thereof - Google Patents

Abstract

The preparation method of the corrosion inhibitor for dynamic cleaning of the high Wen Xiaosuan washing liquid comprises the following raw materials in parts by mass: 2-4 parts of E-51 epoxy resin; 0.5-1 part of triglycidyl isocyanurate; 0.2-0.5 part of pentaerythritol tetraglycidyl ether; DMF 0.3-0.6 parts; 0.5-1 part of water; 0.08-0.15 part of 2-methylimidazole; 0.1-0.3 part of ethylenediamine; 0.5-0.8 part of ethanolamine. The corrosion inhibitor for dynamic cleaning of the high Wen Xiaosuan washing liquor has the advantages that the epoxy equivalent is more than 1500g/mol, the molecular weight is larger, the corrosion inhibitor cannot be damaged due to oxidization of nitric acid, and the corrosion inhibitor contains regular hydroxyl, amino, imidazoline ring and other groups, has strong and stable adsorption effect on metal base materials, has good water solubility and storage stability, and has excellent corrosion inhibition performance in the high-temperature dynamic cleaning process of the nitric acid washing liquor.

Description

Corrosion inhibitor for dynamic cleaning of high-temperature nitric acid lotion and preparation method thereof

technical field

The invention relates to the field of metal electroplating, in particular to a corrosion inhibitor for dynamic cleaning of a high-temperature nitric acid lotion used before metal electroplating and a preparation method thereof.

Background technique

Before the metal is electroplated or painted, it generally needs to be pickled to remove the oxide film on the surface, so as to achieve the effect of excellent film adhesion and comprehensive performance of the subsequent coating.

For metals with less oxide film, ordinary room temperature pickling is generally used, and normal temperature pickling generally uses hydrochloric acid solution. corrosion.

For heavily rusted metal substrates, high-temperature pickling is generally used in order to clean thoroughly, speed up the removal of oxide film, and improve production efficiency. The high temperature is generally around 80°C, and the most commonly used pickling solution is nitric acid medium.

In the pickling process, in order to reduce the corrosion of the metal substrate itself by the pickling solution and achieve the effect of removing only the oxide film as much as possible while lowering the consumption of the metal substrate, it is generally necessary to add a pickling corrosion inhibitor to the pickling solution. The pickling corrosion inhibitor has the ability to combine with the metal substrate, and forms an adsorption layer on the surface of the metal substrate to isolate or slow down the corrosion of the metal substrate by the acid solution.

For pickling at room temperature, there are many types of corrosion inhibitors that can be used, such as the commonly used urotropine, thiourea, potassium thiocyanate, imidazoline, etc. as the main corrosion inhibitor components. The molecules of the agent products are small, all of which are single-molecule substances, and can form a relatively stable adsorption layer with the surface of the metal substrate at room temperature.

However, in the process of high-temperature pickling, due to the high temperature, the corrosion rate of the acid solution is significantly enhanced, and the molecular motion is intensified. The single-molecule corrosion inhibitor cannot form a stable adsorption layer on the surface of the metal substrate, and it is prone to desorption, which leads to its corrosion inhibition ability. Significantly decreased. Moreover, for nitric acid medium, it has a certain oxidation ability at high temperature, which will also lead to oxidation and deactivation of single-molecule corrosion inhibitor products. Bring greater losses to the enterprise.

In response to this problem, some related manufacturers have also conducted research. For example, the products in ZL201910231996.X are suitable for brass materials, and the highest temperature can reach 50°C at medium temperature, and the static corrosion inhibition effect is obvious. However, in order to improve the cleaning efficiency, manufacturers often use high-temperature dynamic pickling method. Due to the small molecular weight of the above-mentioned corrosion inhibitors, the corrosion inhibition effect of the above-mentioned corrosion inhibitors is significantly reduced under high-temperature dynamic conditions.

Therefore, need badly a kind of new corrosion inhibitor suitable for dynamic cleaning of high-temperature nitric acid lotion to solve the above-mentioned technical problems.

Contents of the invention

In order to solve the above-mentioned technical problems, a corrosion inhibitor for dynamic cleaning of high-temperature nitric acid lotion of the present invention and a preparation method thereof are proposed.

The preparation method of corrosion inhibitor for dynamic cleaning of high-temperature nitric acid lotion of the present invention comprises the following raw materials in parts by mass:

Wherein, the preparation method of the corrosion inhibitor for dynamic cleaning of the above-mentioned high-temperature nitric acid lotion also includes the following steps:

A. Stir and mix the formula amount of 2-methylimidazole, ethylenediamine and water at room temperature until completely dissolved to obtain a mixed solution, which is added to the high level tank for later use;

B. Add the E-51 epoxy resin, triglycidyl isocyanurate, pentaerythritol tetraglycidyl ether and DMF into the reactor, and mix thoroughly at 35-40°C until they dissolve into a homogeneous phase;

C. Evenly drop the mixed solution obtained in step A into the reactor to react with the material in step B. After the dropwise addition, continue to keep warm at 35-40°C for a period of time;

D. When the epoxy equivalent of the system mixture>500g/mol, add the ethanolamine of formula quantity and carry out chain extension reaction for a period of time;

D. When the epoxy equivalent of the system mixture is greater than 1500g/mol, stop the reaction and discharge the material to obtain the corrosion inhibitor for dynamic cleaning of the high-temperature nitric acid lotion.

Wherein, in the step A, 2-methylimidazole, ethylenediamine and water are added into a mixer for mixing.

Wherein, in the step A, pump the mixed solution into the elevated tank for standby.

Wherein, the reactor is a reactor.

Wherein, in the step C, the mixed solution obtained in the step A is added dropwise to the reactor by opening the control valve of the head tank containing the mixed solution.

Wherein, in the step C, the dropping time is controlled within 1.5-2.5h (preferably 2h) to finish the dropping.

The present invention also provides the corrosion inhibitor for dynamic cleaning of high-temperature nitric acid lotion prepared by the method for preparing the corrosion inhibitor for dynamic cleaning of high-temperature nitric acid lotion.

Wherein, the appearance of the corrosion inhibitor for dynamic cleaning of high-temperature nitric acid lotion is a uniform viscous liquid with a pH value of 8-9 and an epoxy equivalent of >1500 g/mol.

Compared with the prior art, the present invention has the following advantages:

1. The present invention mainly uses E-51 epoxy resin, triglycidyl isocyanurate, pentaerythritol tetraglycidyl ether, DMF, water, ethylenediamine, ethanolamine, 2-methylimidazole, etc. to react to obtain the obtained Corrosion inhibitor for dynamic cleaning of high temperature nitric acid lotion.

2. The corrosion inhibitor for dynamic cleaning of high-temperature nitric acid lotion has an epoxy equivalent of >1500g/mol, a large molecular weight, will not be oxidized by nitric acid and will not be destroyed, and contains regular hydroxyl groups, amino groups, imidazoline rings and other groups, Strong and stable adsorption with metal substrates, good water solubility and storage stability of the product, excellent corrosion inhibition performance during high temperature dynamic cleaning with nitric acid lotion.

Detailed ways

Below in conjunction with embodiment, the present invention is further described in detail, the purpose is to better understand content of the present invention, therefore, following embodiment is only explanation, does not limit protection scope of the present invention, those skilled in the art can according to the present invention The content makes some non-essential improvements and adjustments to the present invention.

Example 1

A method for preparing a corrosion inhibitor for dynamic cleaning of a high-temperature nitric acid lotion, comprising the following raw materials in parts by mass:

Further, the preparation method comprises the following steps:

A. Add the formula amount of 2-methylimidazole, ethylenediamine and water into the mixer, stir and mix at room temperature until completely dissolved, then pump the mixed solution into the high-level tank for later use;

B. Add the E-51 epoxy resin, triglycidyl isocyanurate, pentaerythritol tetraglycidyl ether and DMF into the reaction kettle, and mix thoroughly at 35°C until they dissolve into a homogeneous phase;

C. Open the control valve of the head tank, evenly drop the mixed solution in step A into the reaction kettle, and control the dropping time at 2.5h. After the dropping, continue to keep warm at 35°C for a period of time;

D. When the epoxy equivalent of the system mixture>500g/mol, add the ethanolamine of formula quantity and carry out chain extension reaction for a period of time;

D. When the epoxy equivalent of the system mixture is greater than 1500g/mol, stop the reaction and discharge the material to obtain the corrosion inhibitor for dynamic cleaning of the high-temperature nitric acid lotion.

Example 2

A method for preparing a corrosion inhibitor for dynamic cleaning of a high-temperature nitric acid lotion, comprising the following raw materials in parts by mass:

Further, the preparation method comprises the following steps:

A. Add the formula amount of 2-methylimidazole, ethylenediamine and water into the mixer, stir and mix at room temperature until completely dissolved, then pump the mixed solution into the high-level tank for later use;

B. Add the E-51 epoxy resin, triglycidyl isocyanurate, pentaerythritol tetraglycidyl ether and DMF into the reaction kettle, and mix them fully at 40°C until they dissolve into a homogeneous phase;

C. Open the control valve of the head tank, and evenly drop the mixed solution in step A into the reaction kettle. The dropping time is controlled at 1.5h. After the dropping, continue to keep warm at 40°C for a period of time;

D. When the epoxy equivalent of the system mixture>500g/mol, add the ethanolamine of formula quantity and carry out chain extension reaction for a period of time;

D. When the epoxy equivalent of the system mixture is greater than 1500g/mol, stop the reaction and discharge the material to obtain the corrosion inhibitor for dynamic cleaning of the high-temperature nitric acid lotion.

Example 3

A method for preparing a corrosion inhibitor for dynamic cleaning of a high-temperature nitric acid lotion, comprising the following raw materials in parts by mass:

Further, the preparation method comprises the following steps:

A. Add the formula amount of 2-methylimidazole, ethylenediamine and water into the mixer, stir and mix at room temperature until completely dissolved, then pump the mixed solution into the high-level tank for later use;

B. Add the E-51 epoxy resin, triglycidyl isocyanurate, pentaerythritol tetraglycidyl ether and DMF into the reaction kettle, and mix them fully at 37°C until they dissolve into a homogeneous phase;

C. Open the control valve of the head tank, evenly drop the mixed solution in step A into the reaction kettle, and control the dropping time at 2.0h. After the dropping, continue to keep warm at 37°C for a period of time;

D. When the epoxy equivalent of the system mixture>500g/mol, add the ethanolamine of formula quantity and carry out chain extension reaction for a period of time;

D. When the epoxy equivalent of the system mixture is greater than 1500g/mol, stop the reaction and discharge the material to obtain the corrosion inhibitor for dynamic cleaning of the high-temperature nitric acid lotion.

Example 4

A method for preparing a corrosion inhibitor for dynamic cleaning of a high-temperature nitric acid lotion, comprising the following raw materials in parts by mass:

Further, the preparation method comprises the following steps:

A. Add the formula amount of 2-methylimidazole, ethylenediamine and water into the mixer, stir and mix at room temperature until completely dissolved, then pump the mixed solution into the high-level tank for later use;

B. Add the E-51 epoxy resin, triglycidyl isocyanurate, pentaerythritol tetraglycidyl ether and DMF into the reaction kettle, and mix them fully at 38°C until they dissolve into a homogeneous phase;

C. Open the control valve of the head tank, evenly drop the mixed solution in step A into the reaction kettle, and control the dropping time at 1.8h. After the dropping, continue to keep warm at 38°C for a period of time;

D. When the epoxy equivalent of the system mixture>500g/mol, add the ethanolamine of formula quantity and carry out chain extension reaction for a period of time;

D. When the epoxy equivalent of the system mixture is greater than 1500g/mol, stop the reaction and discharge the material to obtain the corrosion inhibitor for dynamic cleaning of the high-temperature nitric acid lotion.

Comparative example 1

The product in Example 1 in ZL201910231996.X was used as Comparative Example 1 to test the corrosion inhibition performance.

Comparative example 2

The product in Example 1 in ZL201510879404.7 was used as Comparative Example 2 to test the corrosion inhibition performance.

Comparative example 3

The product in Example 1 in ZL201810005486.6 was used as Comparative Example 3 to test the corrosion inhibition performance.

Test method for corrosion inhibition performance:

The corrosion inhibition rate of the dynamic cleaning process is tested according to GB/T 18175-2000 "Determination of Corrosion Inhibition Performance of Water Treatment Agents by Rotary Coupon Method", in which the washing solution is 10% nitric acid solution and 20% nitric acid The solution is tested, and the quality of the corrosion inhibitor is 0.5% of the mass of the nitric acid lotion; time: 72h; temperature of the lotion: 80°C; linear velocity of the test piece: 0.35m/s; material of the test piece: 20# carbon steel hanging piece .

The test results are shown in Table 1.

Table 1 is prepared by the performance test result of the corrosion inhibitor of embodiment and comparative example

From the comparison of Examples 1-4 and Comparative Examples 1-3 in Table 1, it can be seen that the product of the present invention slows down in the dynamic cleaning process of nitric acid lotion at 80°C/72h through mutual reactions and synergistic effects between the components. Excellent corrosion performance, whether it is 10% mass concentration or 20% nitric acid washing solution, the dynamic corrosion inhibition rate is above 95%, and it has excellent storage stability, and long-term storage does not occur stratification, settlement and other phenomena.

The product in Comparative Example 1 is used as a corrosion inhibitor. After adding 0.5% of the mass of nitric acid lotion, the weight loss is obvious after dynamic cleaning at 80°C/72h. In the nitric acid lotion (mass concentration 10% or 20%), the corrosion inhibition rate is only It can reach between 87-91%, obviously lower than the product of the present invention, and because it is a compound product, a small amount of solid matter will settle after long-term storage.

The corrosion inhibitor products in Comparative Example 2 and Comparative Example 3, due to small molecules and low solid content of the product, the formed adsorption film layer is not firm, and is easily destroyed under high temperature and dynamic cleaning, resulting in the use of nitric acid lotion Under the condition of high temperature dynamic cleaning (80℃/72h), the corrosion inhibition effect is poor, and the corrosion inhibition performance is lower than 80%.

Apparently, the above-mentioned embodiments are only examples for clear description, rather than limiting the implementation. For those of ordinary skill in the art, other changes or changes in different forms can be made on the basis of the above description. It is not necessary and impossible to exhaustively list all the implementation manners here. And the obvious changes or changes derived therefrom are still within the scope of protection of the present invention.

Claims (7)

1. The preparation method of the corrosion inhibitor for dynamic cleaning of the high Wen Xiaosuan washing liquid comprises the following raw materials in parts by mass:

the preparation method comprises the following steps:

A. stirring and mixing 2-methylimidazole, ethylenediamine and water in a formula amount at room temperature until the components are completely dissolved to obtain a mixed solution, and adding the mixed solution into a head tank for later use;

B. adding E-51 epoxy resin, triglycidyl isocyanurate, pentaerythritol tetraglycidyl ether and DMF (dimethyl formamide) in the formula amount into a reactor, and fully mixing at 35-40 ℃ until the mixture is dissolved into homogeneous phase;

C. uniformly dripping the mixed solution obtained in the step A into a reactor to react with the materials in the step B, and continuously carrying out heat preservation reaction for a period of time at 35-40 ℃ after dripping is finished;

D. when the epoxy equivalent of the system mixture is more than 500g/mol, adding the ethanolamine with the formula amount for chain extension reaction for a period of time;

D. stopping the reaction when the epoxy equivalent of the system mixture is more than 1500g/mol, and discharging to obtain the corrosion inhibitor for dynamic cleaning of the high-temperature nitric acid washing liquid;

the corrosion inhibitor obtained has an epoxide equivalent of > 1500 g/mol.

2. The method for preparing a corrosion inhibitor according to claim 1, wherein in the step A, 2-methylimidazole, ethylenediamine and water are added into a mixer to be mixed.

3. The method for preparing corrosion inhibitor according to claim 1, wherein in the step A, the mixed solution is pumped into an elevated tank for standby.

4. The method for producing a corrosion inhibitor according to claim 1, wherein in the step C, the mixed solution obtained in the step A is dropped into the reactor by opening a control valve of an overhead tank containing the mixed solution.

5. The method for preparing a corrosion inhibitor according to claim 1, wherein in the step C, the dripping time is controlled to be 1.5-2.5 h.

6. The corrosion inhibitor for dynamic cleaning of high Wen Xiaosuan lotion, which is prepared by the method for preparing the corrosion inhibitor for dynamic cleaning of high Wen Xiaosuan lotion according to any one of claims 1 to 5.

7. The corrosion inhibitor for dynamic cleaning of high Wen Xiaosuan lotion according to claim 6, wherein the corrosion inhibitor has a pH of 8-9 and an epoxy equivalent of > 1500 g/mol.