Water-based alkaline cleaning agent and method for preparing the same

Abstract

The present application relates to the field of cleaning agent, provide a kind of water-based alkaline cleaning agent and its preparation method, with 100wt% count, the cleaning agent includes the following raw materials: sodium hydroxide 5-8%, acidic substance 9-13%, chelating dispersant 5.5-10.5%, passivation agent 1-4%, organic amine corrosion inhibitor 0.2-0.4%, antirust agent 0.2-0.4%, surfactant 8-12%, the rest is water.The water-based alkaline cleaning agent provided by the present application has good cleaning effect, and also has good flash rust and passivation function.

Description

Technical Field

[0001] This invention relates to the field of cleaning agents, and in particular to a water-based alkaline cleaning agent and its preparation method. Background Technology

[0002] During processing, storage, and transportation, metal products are prone to accumulating contaminants such as oil, rust, and scale, requiring cleaning. Traditional metal cleaning agents are primarily solvent-based, but they suffer from drawbacks such as significant environmental pollution and poor safety. With increasing environmental awareness, water-based cleaning agents are gradually becoming the mainstream approach for metal cleaning. Based on pH values, water-based cleaning agents are mainly classified into alkaline, acidic, and neutral water-based cleaning agents. Water-based alkaline cleaning agents have gained significant attention due to their advantages such as good penetration and emulsification.

[0003] Currently, the application of alkaline water-based industrial cleaning agents is gradually maturing, but there are still some shortcomings. Traditional water-based alkaline cleaning agents usually only have cleaning functions and lack anti-flash rust and passivation functions, which can easily lead to flash rust during the cleaning process, affecting the appearance and performance of metal products. Alternatively, cleaning agents on the market may add a single corrosion inhibitor to play the role of anti-flash rust and passivation, but they still have the problems of short anti-flash rust time or poor density and stability of passivation film.

[0004] Patent CN 117757575 A discloses an alkaline water-based cleaning agent comprising the following raw materials by weight percentage: 5-15% cosolvent, 0.1-3% surfactant, 1%-10% alkaline salt, 3%-6% corrosion inhibitor, 0.005%-0.015% defoamer, and the balance being water. The corrosion inhibitor is one or a mixture of inorganic and organic corrosion inhibitors. In Example 1, the inorganic corrosion inhibitor is sodium nitrite, and the organic corrosion inhibitor is triethanolamine. Sodium nitrite is carcinogenic, and both sodium nitrite and triethanolamine have limited anti-flash rust and passivation effects.

[0005] Therefore, there is an urgent need in the market for a water-based alkaline cleaning agent that combines good anti-flash rust and passivation functions. Summary of the Invention

[0006] In view of the problems existing in the prior art, the present invention discloses a water-based alkaline cleaning agent. The cleaning agent uses sodium hydroxide as the alkaline component, adds a designed and synthesized passivating agent, and combines it with acidic substances, chelating dispersants, organic amine corrosion inhibitors, rust inhibitors and surfactants, so that it has both good anti-flash rust and passivation functions.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The present invention provides a water-based alkaline cleaning agent, which, in 100 wt%, comprises the following raw materials: 5-8% sodium hydroxide, 9-13% acidic substances, 5.5-10.5% chelating dispersant, 1-4% passivating agent, 0.2-0.4% organic amine corrosion inhibitor, 0.2-0.4% rust inhibitor, 8-12% surfactant, and the balance being water.

[0008] In some embodiments of the present invention, the acidic substance is a mixture of sebacic acid, boric acid, neodecanoic acid and octanoic acid.

[0009] Preferably, by weight, the acidic substances include: 1-2 parts sebacic acid, 4-6 parts boric acid, 2-3 parts neodecanoic acid, and 2-3 parts octanoic acid.

[0010] Boric acid, as a weak acid, can form a buffer pair with sodium hydroxide to stabilize pH. Long-chain carboxylic acids, neodecanoic acid and octanoic acid, can achieve directional adsorption on metal surfaces. The dicarboxyl structure of sebacic acid can form a stable chelate film with metal ions, thereby enhancing the rust prevention effect. In other words, the applicant has successfully achieved multiple functions of pH buffering, metal corrosion inhibition, and chelation complexation through the synergistic effect of sebacic acid, boric acid, neodecanoic acid, and octanoic acid.

[0011] In some embodiments of the present invention, the chelating dispersant is a mixture of EDTA-2Na and sodium gluconate.

[0012] Preferably, the chelating dispersant is a mixture of EDTA-2Na and sodium gluconate in a mass ratio of 1:(1.3-2).

[0013] The applicant combines EDTA-2Na and sodium gluconate to form a chelating dispersant that has both good chelating ability and ensures good environmental protection and low cost.

[0014] In some embodiments of the present invention, the method for preparing the passivating agent includes the following steps: (1) Mix sodium tungstate and deionized water, add hydrochloric acid solution to adjust pH to 3.8-4.4, stir to obtain solution 1 for later use; mix sodium molybdate and deionized water, add hydrochloric acid solution to adjust pH to 3.8-4.4, stir to obtain solution 2 for later use; mix sodium silicate and deionized water, add hydrochloric acid solution to adjust pH to 3.8-4.4, stir to obtain solution 3 for later use; (2) Mix solution 1 and solution 2 from step (1), stir, heat to 85-95℃, add solution 3, then add hydrochloric acid aqueous solution to adjust pH=3.8-4.4, stir, react at 85-95℃ for 1-1.5h, cool to room temperature, extract, take the bottom oily substance, heat to evaporate, add to deionized water, recrystallize, and obtain the product for later use; (3) Mix yttrium oxide and hydrochloric acid aqueous solution, heat and stir to obtain solution 4 for later use; add the product of step (2) to deionized water, stir, add cerium nitrate, stir, add solution 4, stir, adjust pH=4-5, add tannic acid while stirring, stir for 40-60 min, filter, take the liquid, and the passivating agent is obtained.

[0015] In some embodiments of the present invention, in step (1), the mass ratio of sodium tungstate, sodium molybdate, and sodium silicate is 1:(0.3-0.5):(0.08-0.12).

[0016] In some embodiments of the present invention, in step (3), the mass ratio of the product to yttrium oxide, cerium nitrate, and tannic acid is 1:(0.3-0.5):(0.5-0.7):(0.15-0.3).

[0017] Sodium molybdate can ionize into MoO4 in aqueous solution. 2- When in contact with a metal surface, MoO4 2- Sodium molybdate can form insoluble molybdate compounds with metal ions, thereby forming a dense oxide film on the metal surface, isolating the metal from the corrosive medium and thus playing a passivation role. However, the passivation film formed by sodium molybdate alone has poor density and stability, resulting in limited corrosion resistance and passivation effect.

[0018] The applicant first synthesized a tungsten-molybdenum-silicon heteropolyacid (product) using sodium tungstate, sodium molybdate, and sodium silicate as raw materials, and controlled the ratio among the three to achieve both high reactivity and a stable structure, making the passivation film on the metal surface denser and effectively isolating the metal from the corrosive medium. Furthermore, the applicant introduced two rare earth elements, cerium and yttrium, through yttrium oxide and cerium nitrate. This forms a hydroxide colloid on the metal surface to inhibit the cathodic reaction, further improving the stability of the passivation film and enabling the cleaning agent to maintain good passivation performance even under harsh environments such as high temperature and strong acid. Cerium nitrate can also quickly form a temporary protective film on the metal surface, providing some anti-flash rust effect. Even further, the applicant introduced a certain amount of tannic acid, which forms an organic complex film by complexing with metal ions, synergistically improving the passivation effect of the cleaning agent. The phenolic hydroxyl groups of tannic acid can also form hydrogen bonds with the tungsten-molybdenum-silicon heteropolyacid, thus giving the passivating agent good stability.

[0019] In some embodiments of the present invention, the organic amine corrosion inhibitor is dicyclohexylamine.

[0020] In some embodiments of the present invention, the rust inhibitor is benzotriazole.

[0021] The applicant added a certain amount of organic amine corrosion inhibitor dicyclohexylamine and rust inhibitor benzotriazole, which synergistically improved the anti-flash rust performance of the cleaning agent.

[0022] In some embodiments of the present invention, the surfactant is a polyoxyethylene ether.

[0023] In another aspect, the present invention provides a method for preparing a water-based alkaline cleaning agent, comprising the following steps: A water-based alkaline cleaning agent is obtained by mixing sodium hydroxide, acidic substances, chelating dispersants, passivating agents, organic amine corrosion inhibitors, rust inhibitors, surfactants, and water, and stirring.

[0024] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention discloses a water-based alkaline cleaning agent. The cleaning agent uses sodium hydroxide as the alkaline component, adds a designed and synthesized passivating agent, and combines it with acidic substances, chelating dispersants, organic amine corrosion inhibitors, rust inhibitors and surfactants. Through the synergistic effect between the components, it has both good anti-flash rust and passivation functions.

[0025] (2) The present invention designs and synthesizes a passivating agent. First, a tungsten-molybdenum-silicon heteropoly acid is synthesized using sodium tungstate, sodium molybdate and sodium silicate as raw materials. The ratio between the three is controlled to make it have both high reactivity and stable structure, so that the passivation film on the metal surface is more dense and effectively isolates the metal from the contact with the corrosive medium. Furthermore, the applicant introduces two rare earth elements, cerium and yttrium, through yttrium oxide and cerium nitrate, as well as a certain amount of tannic acid, to synergistically improve the passivation effect and stability of the cleaning agent, and to a certain extent improve the anti-flash rust performance of the cleaning agent. Detailed Implementation

[0026] The present invention will be described below with reference to specific embodiments. It should be noted that the following embodiments are examples of the present invention and are used only to illustrate the invention, not to limit it. Other combinations and various modifications within the scope of the present invention can be made without departing from its spirit or scope.

[0027] In the following examples and comparative examples, except for the passivating agent, all other compound monomers and related reagents used were commercially available. Among them, the polyoxyethylene ether surfactant was Nourion Berol 266.

[0028] Preparation Example 1 The method for synthesizing passivating agent A includes the following steps: (1) Mix 50g sodium tungstate and 150ml deionized water, add 0.1mol / L hydrochloric acid aqueous solution to adjust pH=4, stir well to obtain solution 1 for later use; mix 20g sodium molybdate and 80ml deionized water, add 0.1mol / L hydrochloric acid aqueous solution to adjust pH=4, stir well to obtain solution 2 for later use; mix 5g sodium silicate and 30ml deionized water, add 0.1mol / L hydrochloric acid aqueous solution to adjust pH=4, stir well to obtain solution 3 for later use; (2) Mix solution 1 and solution 2 from step (1), stir evenly, heat to 90°C, add solution 3, then add 0.5 mol / L sulfuric acid aqueous solution to adjust pH=4, stir evenly, react at 90°C for 1.2 h, cool to room temperature, extract (a mixed solution of 30 ml ethyl acetate and 30 ml 60 wt% sulfuric acid aqueous solution), take the bottom oily substance, heat at 50°C to evaporate to solid, add to deionized water, recrystallize to obtain the product for later use; (3) Mix 10g of yttrium oxide and 100ml of 6mol / L hydrochloric acid aqueous solution, heat to 80℃, stir for 1.5h to obtain solution 4 for later use; add 25g of the product of step (2) to 250ml of deionized water, stir evenly at 40℃, add 15g of cerium nitrate, stir evenly, add solution 4, stir evenly, adjust pH=4.5 with 0.1mol / L hydrochloric acid aqueous solution or 0.1mol / L sodium hydroxide aqueous solution, add 6g of tannic acid while stirring, stir for 50min, filter, take the liquid to obtain passivating agent A.

[0029] Preparation Example 2 Passivating agent B is implemented in the same way as passivating agent A, except that the mass of sodium molybdate in step (1) is replaced with 12g.

[0030] Preparation Example 3 Passivating agent C is implemented in the same way as passivating agent A, except that the mass of sodium silicate in step (1) is replaced with 2g.

[0031] Preparation Example 4 Passivating agent D is implemented in the same way as passivating agent A, except that the mass of yttrium oxide in step (3) is replaced with 5g.

[0032] Preparation Example 5 Passivating agent E is implemented in the same way as passivating agent A, except that the mass of cerium nitrate in step (3) is replaced with 10g.

[0033] Preparation Example 6 Passivating agent F is implemented in the same way as passivating agent A, except that the mass of tannic acid in step (3) is replaced with 2.5g.

[0034] Example 1 A water-based alkaline cleaning agent, in 100 wt%, comprises the following raw materials: 6% sodium hydroxide, 11% acidic substance, 8% chelating dispersant, 2.5% passivating agent A, 0.3% dicyclohexylamine, 0.3% benzotriazole, 10% surfactant Berol 266, and the balance being water.

[0035] By weight, the acidic substances include: 1.5 parts sebacic acid, 5 parts boric acid, 2.5 parts neodecanoic acid, and 2.5 parts octanoic acid.

[0036] The chelating dispersant is a mixture of EDTA-2Na and sodium gluconate in a mass ratio of 1:1.7.

[0037] The preparation method of the water-based alkaline cleaning agent in this embodiment includes the following steps: Sodium hydroxide, acidic substances, chelating dispersants, passivating agent A, dicyclohexylamine, benzotriazole, surfactant Berol 266, and water are mixed and stirred evenly to obtain a water-based alkaline cleaning agent.

[0038] Example 2 A water-based alkaline cleaning agent, in 100 wt%, comprises the following raw materials: 5% sodium hydroxide, 9% acidic substance, 5.5% chelating dispersant, 1% passivating agent A, 0.2% dicyclohexylamine, 0.2% benzotriazole, 8% surfactant Berol 266, and the balance being water.

[0039] By weight, the acidic substances include: 1 part sebacic acid, 4 parts boric acid, 2 parts neodecanoic acid, and 2 parts octanoic acid.

[0040] The chelating dispersant is a mixture of EDTA-2Na and sodium gluconate in a mass ratio of 1:1.3.

[0041] The preparation method of the water-based alkaline cleaning agent in this embodiment is the same as that in Example 1.

[0042] Example 3 A water-based alkaline cleaning agent, in 100 wt%, comprises the following raw materials: 8% sodium hydroxide, 13% acidic substance, 10.5% chelating dispersant, 4% passivating agent A, 0.4% dicyclohexylamine, 0.4% benzotriazole, 12% surfactant Berol 266, and the balance being water.

[0043] By weight, the acidic substances include: 2 parts sebacic acid, 6 parts boric acid, 3 parts neodecanoic acid, and 3 parts octanoic acid.

[0044] The chelating dispersant is a mixture of EDTA-2Na and sodium gluconate in a mass ratio of 1:2.

[0045] The preparation method of the water-based alkaline cleaning agent in this embodiment is the same as that in Example 1.

[0046] Example 4 This embodiment provides a water-based alkaline cleaning agent and its preparation method. The specific implementation method is the same as in Embodiment 1, except that passivating agent A is replaced by passivating agent B in an equal amount.

[0047] Example 5 This embodiment provides a water-based alkaline cleaning agent and its preparation method. The specific implementation method is the same as that in Embodiment 1, except that passivating agent A is replaced by passivating agent C in an equal amount.

[0048] Example 6 This embodiment provides a water-based alkaline cleaning agent and its preparation method. The specific implementation method is the same as that in Embodiment 1, except that passivating agent D is used to replace passivating agent A in an equal amount.

[0049] Example 7 This embodiment provides a water-based alkaline cleaning agent and its preparation method. The specific implementation method is the same as that in Embodiment 1, except that passivating agent A is replaced by an equal amount of passivating agent E.

[0050] Example 8 This embodiment provides a water-based alkaline cleaning agent and its preparation method. The specific implementation method is the same as that in Embodiment 1, except that passivating agent A is replaced by an equal amount of passivating agent F.

[0051] Example 9 This embodiment provides a water-based alkaline cleaning agent and its preparation method. The specific implementation method is the same as that in Embodiment 1, except that sodium molybdate is used to replace passivating agent A in an equal amount.

[0052] Performance testing The relevant performance of the water-based alkaline cleaning agents in Examples 1-9 above was tested, and the test results are shown in Tables 1-2.

[0053] Test piece: Carbon steel (50mm×120mm); 1. Cleaning effect: The washing performance of the cleaning agents in Examples 1-3 on the test pieces was tested. The treated test pieces were weighed on a balance and recorded as m1. The oil stains were drained and weighed and recorded as m2. After weighing, the test pieces were soaked in the cleaning agent at 40℃ for 3 minutes, then rinsed for 2 minutes. After being taken out, they were washed with water and dried in an oven at 70℃. The weighed mass was recorded as m3. The detergency was calculated as: p=(m2-m3)÷(m2-m1)×100%. The test results are shown in Table 1. 2. Anti-flash rust performance: Under the conditions of temperature 23℃ and relative humidity 50±5%, the test pieces after rust removal treatment were immersed in the cleaning solution of Examples 1-9 for 5 minutes, rinsed with deionized water, and then placed under normal temperature and humidity conditions for 24 hours. The test pieces were observed to see if rust spots appeared on the surface. No obvious rust spots proved that the anti-flash rust performance was good. The test results are shown in Table 2. 3. Passivation performance: The test pieces that have been cleaned and passivated by the cleaning solutions of Examples 1-9 were placed in a salt spray test chamber and subjected to a neutral salt spray test at 35°C and 5wt% NaCl aqueous solution. After 72 hours, the surface corrosion of the test pieces was observed. No obvious corrosion indicates good passivation performance. The test results are shown in Table 2.

[0054] Table 1

[0055] Table 2

[0056] As can be seen from the data in Table 1, the cleaning agents in Examples 1-3 of the present invention all have high detergency, that is, they have good cleaning effect.

[0057] As shown in Table 2, the cleaning agents in Examples 1-3 of this invention exhibit high anti-flash rust and passivation performance. Examples 4-8 involve altering the proportions of the main substances during the passivating agent synthesis process. Changes in the amounts of sodium molybdate and sodium silicate reduced the reactivity and stability of the synthesized tungsten-molybdenum-silicon heteropolyacid, weakening its isolation effect on metals and corrosive media. Changes in the amounts of yttrium oxide and cerium nitrate reduced the effectiveness of the two rare earth elements in improving the stability of the passivation film. Changes in the mass of tannic acid reduced the stability of the organic complex film formed by its complexation with metal ions. All of these factors contribute to varying degrees of decrease in the density and stability of the passivation film formed by the passivating agent and the metal, resulting in poor passivation performance of the cleaning agent. Example 9 involved replacing passivating agent A with an equal amount of sodium molybdate; tests revealed that the cleaning agent exhibited poor anti-flash rust and passivation performance.

[0058] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A water-based alkaline cleaning agent, characterized in that, The cleaning agent comprises, by weight (100 wt%), the following raw materials: 5-8% sodium hydroxide, 9-13% acidic substances, 5.5-10.5% chelating dispersant, 1-4% passivating agent, 0.2-0.4% organic amine corrosion inhibitor, 0.2-0.4% rust inhibitor, 8-12% surfactant, and the balance being water.

2. The water-based alkaline cleaning agent according to claim 1, characterized in that, The acidic substance is a mixture of sebacic acid, boric acid, neodecanoic acid, and octanoic acid.

3. The water-based alkaline cleaner as set forth in claim 1, characterized by, The chelating dispersant is a mixture of EDTA-2Na and sodium gluconate.

4. The aqueous-based alkaline cleaner of claim 1, wherein, The method for preparing the passivating agent includes the following steps: (1) Mix sodium tungstate and deionized water, add hydrochloric acid solution to adjust pH to 3.8-4.4, stir to obtain solution 1 for later use; mix sodium molybdate and deionized water, add hydrochloric acid solution to adjust pH to 3.8-4.4, stir to obtain solution 2 for later use; mix sodium silicate and deionized water, add hydrochloric acid solution to adjust pH to 3.8-4.4, stir to obtain solution 3 for later use; (2) Mix solution 1 and solution 2 from step (1), stir, heat to 85-95℃, add solution 3, then add hydrochloric acid aqueous solution to adjust pH=3.8-4.4, stir, react at 85-95℃ for 1-1.5h, cool to room temperature, extract, take the bottom oily substance, heat to evaporate, add to deionized water, recrystallize, and obtain the product for later use; (3) Mix yttrium oxide and hydrochloric acid aqueous solution, heat and stir to obtain solution 4 for later use; add the product of step (2) to deionized water, stir, add cerium nitrate, stir, add solution 4, stir, adjust pH=4-5, add tannic acid while stirring, stir for 40-60 min, filter, take the liquid, and the passivating agent is obtained.

5. The aqueous-based alkaline cleaner of claim 4, wherein, In step (1), the mass ratio of sodium tungstate, sodium molybdate, and sodium silicate is 1:(0.3-0.5):(0.08-0.12).

6. The water-based alkaline cleaner according to claim 4, wherein In step (3), the mass ratio of the product to yttrium oxide, cerium nitrate, and tannic acid is 1:(0.3-0.5):(0.5-0.7):(0.15-0.3).

7. The water-based alkaline cleaner of claim 1, wherein, The organic amine corrosion inhibitor is dicyclohexylamine.

8. The water-based alkaline cleaner as set forth in claim 1, characterized by, The rust inhibitor is benzotriazole.

9. The aqueous-based alkaline cleaner of claim 1, wherein, The surfactant is a polyoxyethylene ether.

10. A method for preparing a water-based alkaline cleaning agent according to any one of claims 1-9, characterized in that, Includes the following steps: A water-based alkaline cleaning agent is obtained by mixing sodium hydroxide, acidic substances, chelating dispersants, passivating agents, organic amine corrosion inhibitors, rust inhibitors, surfactants, and water, and stirring.

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