Blue passivated direct quenching liquid and preparation method thereof

Abstract

The present application relates to the technical field of metal surface treatment, and particularly relates to a blue passivation direct cooling liquid and a preparation method thereof, which is prepared from the following raw materials in parts by weight: water-based polyphenylene sulfide 50-70 parts, ammonium molybdate 3-8 parts, ammonium metavanadate 5-10 parts, phosphoric acid 2-10 parts, blue color paste 1-2 parts, defoaming agent 0.5-1 part, leveling agent 0.5-1 part, cosolvent 5-8 parts, film-forming aid 6-9 parts, crosslinking agent 2-4 parts and deionized water 20-30 parts. The blue passivation direct cooling liquid provided by the present application has the ability to cope with high temperature, acid and other harsh environments, and has good adhesion performance, can maintain good performance even after long-term exposure to outdoor environments, and the blue passivation direct cooling liquid prepared by the present application has high gloss, which can facilitate detection of whether film formation is achieved.

Description

Technical Field

[0001] This invention relates to the field of metal surface treatment technology, and in particular to a blue passivation direct cooling liquid and its preparation method. Background Technology

[0002] The electrochemical behavior of a metal caused by changes in its surface state gives it certain characteristics of noble metals (low corrosion rate, positive electrode potential). If this change occurs naturally between the metal and the medium, it is called chemical passivation or self-passivation.

[0003] Passivation is a process in which metal is treated in a solution of nitrite, nitrate, chromate, or dichromate to form a chromate passivation film on the metal surface. It is often used as a post-treatment for zinc and cadmium plating to improve the corrosion resistance of the plating; to protect non-ferrous metals; and to improve the adhesion of paint films.

[0004] Passivation solutions are solutions that passivate metal surfaces. They are generally used for post-plating treatment of zinc, cadmium, and other coatings. The purpose is to create a surface condition on the coating that prevents normal metal reactions, thereby improving its corrosion resistance and enhancing the product's appearance.

[0005] Chinese patent document CN 106637353 B discloses a passivation treatment solution and method for stainless steel surfaces, comprising: a rare earth metal salt, a silicate, and an oxidant. The rare earth metal salt is cerium sulfate, the silicate is sodium silicate, and the oxidant is potassium permanganate. The above substances are added to a certain amount of distilled water and stirred thoroughly until all the solids are dissolved. This invention uses stainless steel as the working electrode, placing it in the passivation treatment solution to form a three-electrode system with a reference electrode and a counter electrode. The working electrode is anodized, forming a passivation film layer on the stainless steel surface, thus achieving passivation treatment of the stainless steel surface.

[0006] Although the passivating agent in the aforementioned patent has increased corrosion resistance compared to ordinary passivating agents, its adhesion to the metal surface is insufficient. During later use, the passivation layer on its surface is easily detached due to the influence of external environment, friction and impact, and it cannot play a protective role. Summary of the Invention

[0007] In view of this, the purpose of this invention is to provide a blue passivation direct cooling liquid and its preparation method, which is particularly suitable for use under complex working conditions.

[0008] To achieve the above objectives, the present invention provides a blue passivation direct cooling liquid, which is prepared from the following raw materials in parts by weight: 50-70 parts of aqueous polyphenylene sulfide, 3-8 parts of ammonium molybdate, 5-10 parts of ammonium metavanadate, 2-10 parts of phosphoric acid, 1-2 parts of blue pigment, 0.5-1 part of defoamer, 0.5-1 part of leveling agent, 5-8 parts of cosolvent, 6-9 parts of film-forming aid, 2-4 parts of crosslinking agent, and 20-30 parts of deionized water.

[0009] The aqueous polyphenylene sulfide 50-70 parts are prepared from the following raw materials in parts by weight: sulfonated polyphenylene sulfide 40-50 parts, hydrogen peroxide 12-15 parts, acetic acid 15-20 parts, sulfuric acid 5-10 parts, initiator 1-3 parts, and deionized water 60-70 parts.

[0010] The preparation method of the sulfonated polyphenylene sulfide is as follows:

[0011] S11: Disperse polyphenylene sulfide in sulfonating agent, stir well, heat to 100-120℃ under nitrogen atmosphere, keep warm for 1 hour, and obtain unpurified sulfonated polyphenylene sulfide after multiple ultrafiltrations.

[0012] S12: Disperse the unpurified sulfonated polyphenylene sulfide after ultrafiltration in an ethanol solution, heat it in ether and let it stand. Centrifuge and take the lower layer of liquid and dry it under vacuum to obtain sulfonated polyphenylene sulfide.

[0013] In step S11, the ratio of polyphenylene sulfide to sulfonating agent is 80-100g:1-1.5L;

[0014] In step S12, the ratio of unpurified sulfonated polyphenylene sulfide, ethanol, and diethyl ether is 80-100g:0.5-1L:1-2L.

[0015] Furthermore, the preparation method of the aqueous polyphenylene sulfide is as follows:

[0016] Mix hydrogen peroxide, acetic acid, sulfuric acid and deionized water, and stir for 20-30 minutes to obtain an oxidizing agent solution;

[0017] Sulfonated polyphenylene sulfide and an initiator are added to an oxidant solution, and the mixture is heated to 80-100℃ under a nitrogen atmosphere and stirred for 30-50 minutes to obtain aqueous polyphenylene sulfide through polymerization.

[0018] Furthermore, the co-solvent is ethylene glycol ethyl ether acetate, and the film-forming aid is propylene glycol.

[0019] Furthermore, the leveling agent is a polyether siloxane copolymer; the defoamer is an organosilicon defoamer.

[0020] Furthermore, the leveling agent is a polyether polyester modified organosiloxane, and the defoamer is an organosilicone defoamer.

[0021] Furthermore, the crosslinking agent is nano-silica.

[0022] Furthermore, the sulfonating agent is 20% fuming sulfuric acid or concentrated sulfuric acid, and the initiator is ammonium persulfate.

[0023] Furthermore, a method for preparing a blue passivation direct cooling liquid includes the following steps:

[0024] (1) Mix waterborne polyphenylene sulfide, ammonium molybdate, defoamer, cosolvent, leveling agent, film-forming aid, ammonium metavanadate and deionized water, and stir for 20-30 minutes to obtain a mixture.

[0025] (2) Add acid solution while stirring, and adjust the pH of the mixture to 3-4;

[0026] (3) Add the crosslinking agent and blue pigment to the pH-adjusted solution and stir for 10-20 minutes to obtain the blue passivation direct cooling solution.

[0027] Furthermore, in step (2), the acid solution is phosphoric acid, and in step (3), the blue pigment can be a yellow pigment.

[0028] The beneficial effects of this invention are:

[0029] The blue passivation cooling liquid provided by this invention has the ability to cope with harsh environments such as high temperature and acid, and has good adhesion performance. It can ensure that even when exposed to the outdoor environment for a long time, it can maintain good performance. Moreover, the blue passivation cooling liquid prepared by this invention has high gloss, which makes it easy to detect whether a film has formed.

[0030] This invention modifies poorly soluble polyphenylene sulfide by sulfonation and further chemically modifies it to improve its hydrophilicity and subsequent adhesion, making the polyphenylene sulfide soluble in water. The aqueous polyphenylene sulfide is then introduced into the passivation solution, resulting in a passivation layer with high strength, high temperature resistance, and chemical resistance, which in turn gives it excellent impact resistance and corrosion resistance. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0032] The raw materials used in the specific embodiments of this invention are sourced as follows: hydrogen peroxide, phosphoric acid, sulfuric acid, acetic acid, and diethyl ether were purchased from Guangzhou Chemical Reagent Factory; polyphenylene sulfide was purchased from Ticona; and ammonium molybdate and ammonium metavanadate were purchased from Guangdong Wengjiang Chemical Reagent Co., Ltd.

[0033] Example 1: Preparation of a blue passivation direct cooling liquid:

[0034] (1) Disperse 8g of polyphenylene sulfide in 100ml of 20% fuming sulfuric acid, stir well, heat to 105℃ under nitrogen atmosphere, keep warm for 1h, and obtain unpurified sulfonated polyphenylene sulfide after 3 ultrafiltrations.

[0035] (2) Disperse 6g of unpurified sulfonated polyphenylene sulfide in 40ml of ethanol solution, heat 80ml of diethyl ether and let stand, centrifuge and take the lower layer of liquid and dry it under vacuum. Repeat this step twice to obtain sulfonated polyphenylene sulfide.

[0036] (3) Mix 12ml hydrogen peroxide, 16ml acetic acid, 8ml sulfuric acid and 60ml deionized water and stir for 22min to obtain an oxidizing agent solution;

[0037] (4) Add 8g of sulfonated polyphenylene sulfide and initiator to the oxidant solution, heat to 85°C under nitrogen atmosphere, stir for 35min, and the polymerization reaction yields waterborne polyphenylene sulfide.

[0038] (5) Mix 55g of waterborne polyphenylene sulfide, 5g of ammonium molybdate, 6g of ammonium metavanadate, 0.8g of defoamer BYK-8820, 0.6g of leveling agent HY-5030, 6.5g of propylene glycol, 6g of ethylene glycol ethyl ether acetate and 20ml of deionized water, and stir for 20min to obtain a mixture.

[0039] (6) Add 7 ml of phosphoric acid solution while stirring, and adjust the pH of the mixture to 3;

[0040] (7) Add 2g of nano silica and 1ml of blue pigment to the pH-adjusted solution and stir for 12min to obtain blue passivation direct cooling solution.

[0041] Example 2: Preparation of a blue passivation direct cooling liquid:

[0042] (1) Disperse 9g of polyphenylene sulfide in 120ml of 20% fuming sulfuric acid, stir well, heat to 115℃ under nitrogen atmosphere, keep warm for 1h, and obtain unpurified sulfonated polyphenylene sulfide after 3 ultrafiltrations.

[0043] (2) Disperse 8g of unpurified sulfonated polyphenylene sulfide in 70ml of ethanol solution, heat 80ml of diethyl ether and let stand, centrifuge and take the lower layer of liquid and vacuum dry. Repeat this step twice to obtain sulfonated polyphenylene sulfide.

[0044] (3) Mix 13ml hydrogen peroxide, 17ml acetic acid, 8ml sulfuric acid and 65ml deionized water and stir for 25min to obtain an oxidizing agent solution;

[0045] (4) Add 9g of sulfonated polyphenylene sulfide and initiator to the oxidant solution, heat to 90°C under nitrogen atmosphere, stir for 40min, and the polymerization reaction yields waterborne polyphenylene sulfide.

[0046] (5) Mix 60g of waterborne polyphenylene sulfide, 6g of ammonium molybdate, 8g of ammonium metavanadate, 0.8g of defoamer BYK-8820, 0.7g of leveling agent HY-5030, 7g of propylene glycol, 6g of ethylene glycol ethyl ether acetate and 25ml of deionized water, and stir for 20min to obtain a mixture.

[0047] (6) Add 8 ml of phosphoric acid solution while stirring, and adjust the pH of the mixture to 3;

[0048] (7) Add 3g of nano silica and 1ml of blue pigment to the solution after adjusting the pH, stir for 15min to obtain blue passivation direct cooling liquid.

[0049] Example 3: Preparation of a blue passivation direct cooling liquid:

[0050] (1) Disperse 10g of polyphenylene sulfide in 150ml of 20% fuming sulfuric acid, stir well, heat to 120℃ under nitrogen atmosphere, keep warm for 1h, and obtain unpurified sulfonated polyphenylene sulfide after 3 ultrafiltrations.

[0051] (2) Disperse 10g of unpurified sulfonated polyphenylene sulfide in 100ml of ethanol solution, heat 200ml of diethyl ether and let stand, centrifuge and take the lower layer of liquid and vacuum dry. Repeat this step twice to obtain sulfonated polyphenylene sulfide.

[0052] (3) Mix 15ml hydrogen peroxide, 20ml acetic acid, 10ml sulfuric acid and 70ml deionized water and stir for 30 minutes to obtain an oxidizing agent solution;

[0053] (4) Add 9g of sulfonated polyphenylene sulfide and initiator to the oxidant solution, heat to 100℃ under nitrogen atmosphere, stir for 50min, and the polymerization reaction yields waterborne polyphenylene sulfide.

[0054] (5) Mix 60g of waterborne polyphenylene sulfide, 8g of ammonium molybdate, 9g of ammonium metavanadate, 1g of defoamer BYK-8820, 1g of leveling agent HY-5030, 8g of propylene glycol, 8g of ethylene glycol ethyl ether acetate and 30ml of deionized water, stir for 30min to obtain a mixture.

[0055] (6) Add 10 ml of phosphoric acid solution while stirring, and adjust the pH of the mixture to 3;

[0056] (7) Add 4g of nano silica and 1ml of blue pigment to the solution after adjusting the pH, stir for 20min to obtain blue passivation direct cooling liquid.

[0057] Comparative Example 1:

[0058] The difference between Comparative Example 1 and Example 2 is that step (4) is removed and the aqueous polyphenylene sulfide in step (5) is replaced with sulfonated polyphenylene sulfide. The remaining steps are the same as in Example 2, and will not be repeated here.

[0059] Comparative Example 2:

[0060] The difference between Comparative Example 2 and Example 2 is that the aqueous polyphenylene sulfide in step 5 is replaced with an aqueous polyurethane dispersion. The remaining steps are the same as in Example 2 and will not be repeated here.

[0061] Comparative Example 3:

[0062] The difference between Comparative Example 3 and Example 2 is that the waterborne polyphenylene sulfide in step 5 is replaced with waterborne acrylic resin. The waterborne acrylic resin was purchased from Guangzhou Ruyi Chemical Co., Ltd. The remaining steps are the same as in Example 2, and will not be repeated here.

[0063] To demonstrate the performance of the aluminum pigments prepared in the examples and comparative examples, the following verification experiments are provided:

[0064] The experiment used galvanized steel sheets of the same batch with dimensions of 30mm×50mm as experimental materials. The surface of the galvanized steel sheets was polished, then cleaned with an industrial degreasing agent, immersed in a 50℃ water bath for 8 minutes, and then ultrasonically degreased with a degreasing agent. After rinsing with clean water and drying, the passivation solutions produced in Examples 1-3 and Comparative Examples 1-3 were uniformly coated onto the galvanized steel sheets using a coating device, and then cured at 100℃ for 10 minutes to obtain a passivation film layer of 0.60μm.

[0065] Neutral salt spray test: Following the national standard GB / T 10125-2012, a salt solution containing 5% sodium chloride and with a pH of 6.5–7.2 was sprayed using a spray device, allowing the salt spray to settle onto the test specimen. The surface corrosion state was observed after a certain period. The test chamber temperature was required to be 35℃, humidity greater than 95%, mist drop rate 1–2 mL / (h·cm²), and nozzle pressure 80 kPa for 240 hours. The test results are shown in Table 1.

[0066] Adhesion test: The film layer is divided into grids (grid spacing 1mm) using a cross-cut tester. 3M tape is used to adhere to the center of the grid and then peeled off at a 60-degree angle. The adhesion is rated according to the degree of coating peeling, with a total of 6 levels, from 0 to 5.

[0067] Boiling water resistance test: Immerse the galvanized steel sheet in a boiling water bath for 5 minutes and check whether the film layer is damaged or peeled off, and check whether the water turns blue.

[0068] Impact resistance test: A (1000+1)g hammer will be released from a fixed height according to the national standard GB / T 1732-2020 to impact the galvanized steel plate. The passivation film layer will be observed at what height the hammer rises, and cracks, wrinkles and peeling will occur. The hammer will rise 5cm each time, and the impact strength value at that height will be calculated.

[0069] The comprehensive test results are shown in Table 1.

[0070] Table 1 Performance verification experiment results

[0071]

[0072] Data Analysis:

[0073] As can be seen from Examples 1-3, the blue passivation cooling liquid prepared by the present invention has the ability to cope with high temperature and harsh environment, and can maintain good performance even when exposed to outdoor environment for a long time. Moreover, it has high adhesion and will not easily fall off during use.

[0074] As can be seen from the data in Example 2 and Comparative Example 1 above, the waterborne polyphenylene sulfide prepared by the present invention can effectively improve the corrosion resistance and adhesion of the passivation coating. This is mainly because the waterborne polyphenylene sulfide is uniformly dispersed, which increases the high temperature resistance of the passivation coating. Moreover, its own chemical resistance greatly enhances the corrosion resistance of the entire passivation coating.

[0075] As can be seen from the data in Example 2 and Comparative Example 1 above, the adhesion ability of directly using sulfonated polyphenylene sulfide decreases, mainly because sulfonated polyphenylene sulfide has strong hydrophobicity, which can lead to agglomeration during subsequent polymerization. However, modifying sulfonated polyphenylene sulfide into water-based polyphenylene sulfide before polymerization with other reagents can effectively prevent agglomeration, thus ensuring its adhesion. Due to the enhanced adhesion and reduced agglomeration, the passivation solution is more uniform, and its overall performance is improved accordingly.

[0076] As can be seen from the data of Comparative Examples 1, 2 and 3 in the table above, the introduction of sulfonated polyphenylene sulfide, compared with the use of existing waterborne resins, introduces the characteristics of polyphenylene sulfide, thus improving the performance of the passivation liquid film layer.

[0077] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity.

[0078] This invention is intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A blue passivating direct cooling liquid, characterized in that, It is prepared from the following raw materials in parts by weight: 50-70 parts of water-based polyphenylene sulfide, 3-8 parts of ammonium molybdate, 5-10 parts of ammonium metavanadate, 2-10 parts of phosphoric acid, 1-2 parts of blue pigment, 0.5-1 part of defoamer, 0.5-1 part of leveling agent, 5-8 parts of cosolvent, 6-9 parts of film-forming aid, 2-4 parts of crosslinking agent, and 20-30 parts of deionized water; The aqueous polyphenylene sulfide 50-70 parts are prepared from the following raw materials in parts by weight: sulfonated polyphenylene sulfide 40-50 parts, hydrogen peroxide 12-15 parts, acetic acid 15-20 parts, sulfuric acid 5-10 parts, initiator 1-3 parts, and deionized water 60-70 parts. The sulfonated polyphenylene sulfide is prepared as follows: S11: Disperse polyphenylene sulfide in sulfonating agent, stir well, heat to 100-120℃ under nitrogen atmosphere, keep warm for 1h, and obtain unpurified sulfonated polyphenylene sulfide after multiple ultrafiltrations. S12: Disperse the unpurified sulfonated polyphenylene sulfide after ultrafiltration in an ethanol solution, heat it in ether and let it stand. Centrifuge and take the lower layer of liquid and dry it under vacuum to obtain sulfonated polyphenylene sulfide. In step S11, the ratio of polyphenylene sulfide to sulfonating agent is 80-100g:1-1.5L; In step S12, the ratio of unpurified sulfonated polyphenylene sulfide, ethanol, and diethyl ether is 80-100g:0.5-1L:1-2L. The preparation method of the aqueous polyphenylene sulfide is as follows: Mix hydrogen peroxide, acetic acid, sulfuric acid and deionized water, and stir for 20-30 minutes to obtain an oxidizing agent solution; Sulfonated polyphenylene sulfide and an initiator are added to an oxidant solution, and the mixture is heated to 80-100℃ under a nitrogen atmosphere and stirred for 30-50 minutes to obtain aqueous polyphenylene sulfide through polymerization.

2. The blue passivating direct cooling liquid according to claim 1, characterized in that, The cosolvent is ethylene glycol ethyl ether acetate, and the film-forming aid is propylene glycol.

3. The blue passivating direct cooling liquid according to claim 1, characterized in that, The leveling agent is a polyether siloxane copolymer; the defoamer is an organosilicon defoamer.

4. The blue passivating direct cooling liquid according to claim 1, characterized in that, The leveling agent is a polyether polyester modified organosiloxane, and the defoamer is an organosilicone defoamer.

5. The blue passivating direct cooling liquid according to claim 1, characterized in that, The crosslinking agent is nano-silica.

6. The blue passivating direct cooling liquid according to claim 1, characterized in that, The sulfonating agent is 20% fuming sulfuric acid or concentrated sulfuric acid, and the initiator is ammonium persulfate.

7. The method for preparing the blue passivation direct cooling liquid according to any one of claims 1-6, characterized in that, The steps include the following: (1) Mix water-based polyphenylene sulfide, ammonium molybdate, defoamer, cosolvent, leveling agent, film-forming aid, ammonium metavanadate and deionized water, and stir for 20-30 minutes to obtain a mixture; (2) Add acid solution while stirring, and adjust the pH of the mixture to 3-4; (3) Add the crosslinking agent and blue pigment to the solution after adjusting the pH, stir for 10-20 min to obtain blue passivation direct cooling liquid.

8. The method for preparing the blue passivation direct cooling liquid according to claim 7, characterized in that, In step (2), the acid solution is phosphoric acid.

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