Efficient acidic cleaning agent as well as preparation method and application thereof

Abstract

The invention relates to the technical field of circuit board manufacturing, in particular to an efficient acidic cleaning agent and a preparation method and application thereof. An efficient acidic cleaning agent is prepared from the following raw materials in parts by mass: 22-28 parts of organic acid, 4-6 parts of monoethanolamine, 2-3 parts of a complexing agent, 1-3 parts of a corrosion inhibitor, 5-8 parts of a surfactant, 10-12 parts of a stabilizer, 5-7 parts of asparagine-choline ionic liquid, 0.1-0.2 part of a defoaming agent and 80-100 parts of deionized water. According to the efficient acidic cleaning agent, through the synergistic effect of multiple components, the rapid and excellent oil removal effect is achieved, and meanwhile metal on the surface of a circuit board is protected against corrosion. All the components are matched with one another in the cleaning process and play respective roles together, so that the cleaning effect and the safety are improved.

Description

Technical Field

[0001] The present application relates to the technical field of circuit board manufacturing, and in particular to a high-efficiency acid cleaning agent and a preparation method and application thereof. Background Art

[0002] Printed circuit boards (PCBs) enable interconnection between electronic components and are an indispensable core component of electronic products and electrical equipment. With the development of science and technology and the improvement of consumption levels, people's demand for electronic products is also increasing year by year. As the core component of electronic products, the design, preparation and performance of PCBs largely determine the application reliability and user satisfaction of electronic products.

[0003] During the production and processing of circuit board products, such as after chemical nickel plating, a clean nickel layer is obtained to enhance conductivity and improve soldering performance. However, in the subsequent operation process, a layer of oil will inevitably adhere to the nickel surface, and it will also be contaminated by fingerprints, oil stains, glue marks, oxidation points, etc. If it is not effectively removed, it will affect the quality of subsequent processing or conversion film, and reduce the yield rate of circuit board products. Existing cleaning agents are difficult to effectively remove insoluble pollutants on the surface of PCBs, especially after chemical nickel plating, and are prone to damage sensitive ink layers and photoresists, affecting the functional stability and aesthetics of the circuit board. Summary of the invention

[0004] The purpose of this application is to provide a high-efficiency acid cleaning agent and its preparation method and application in response to the deficiencies of current technology. The high-efficiency acid cleaning agent prepared in this application has a fast and excellent oil removal effect, a detergency of more than 99.89%, will not corrode the metal on the surface of the circuit board during use, and the cleaning agent has good stability at high and low temperatures. The preparation method of this application is simple, the production cost is low, it meets the requirements of green and environmentally friendly production, and meets the oil removal and cleaning of various processes of electroplating processing of various types of circuit boards.

[0005] In the first aspect, the present application provides a high-efficiency acid cleaning agent, which adopts the following technical solution: A high-efficiency acid cleaning agent comprises the following raw materials, measured by weight: 22-28 parts of organic acid, 4-6 parts of monoethanolamine, 2-3 parts of complexing agent, 1-3 parts of corrosion inhibitor, 5-8 parts of surfactant, 10-12 parts of stabilizer, 5-7 parts of asparagine-choline ionic liquid, 0.1-0.2 parts of defoaming agent and 80-100 parts of deionized water.

[0006] By adopting the above technical solution, organic acid: As the main acidic component, organic acid can effectively remove grease and dirt on the surface of the circuit board. Its acidity can react with grease to decompose it into soluble substances, thereby achieving the degreasing effect. Monoethanolamine can adjust the pH value of the cleaning agent to keep it within an appropriate range to avoid corrosion of the metal on the surface of the circuit board. At the same time, monoethanolamine also has a chelating effect and can form a complex with metal ions to reduce the deposition and corrosion of metal ions. The complexing agent can form a stable complex with metal ions to prevent metal ions from being deposited on the surface of the circuit board during the cleaning process, thereby avoiding the occurrence of metal corrosion. The corrosion inhibitor can form a protective film on the surface of the circuit board to prevent the acidic cleaning agent from directly contacting the metal, thereby slowing down the rate of metal corrosion. The surfactant can reduce the surface tension of the cleaning agent, making it easier to penetrate into the tiny pores on the surface of the circuit board and improve the cleaning effect. In addition, the surfactant can also emulsify the grease and disperse it in water, which is convenient for the cleaning agent to be rinsed. The stabilizer can enhance the emulsification performance of the surfactant, making the cleaning agent more stable and not easy to stratify or precipitate. Asparagine-choline ionic liquid has rich functional groups and action sites, which can effectively improve the wettability of the metal surface of the circuit board, making it easier for the cleaning agent to contact the metal surface, thereby improving the degreasing effect. At the same time, asparagine-choline ionic liquid forms a protective film on the metal surface of the circuit board, reducing the corrosion ability of organic acids on the surface metal and protecting the surface of the circuit board from corrosion. The defoamer can eliminate the foam generated during the cleaning process to prevent the foam from affecting the cleaning effect and operational safety. Deionized water is used to dilute other components so that the cleaning agent reaches an appropriate concentration. At the same time, the purity of deionized water is high and impurities will not be introduced to affect the cleaning effect. In summary, the high-efficiency acidic cleaning agent in this application achieves a fast and excellent degreasing effect through the synergistic effect of multiple components, while protecting the metal on the surface of the circuit board from corrosion. The components cooperate with each other during the cleaning process and play their respective roles together to improve the cleaning effect and safety.

[0007] Preferably, the organic acid is at least one of oxalic acid, citric acid and glycine.

[0008] Preferably, the organic acid consists of oxalic acid, citric acid and glycine in a mass ratio of 4:3:3.

[0009] By adopting the above technical solution, the organic acid is composed of oxalic acid, citric acid and glycine in a mass ratio of 4:3:3. This combination allows the advantages of various acids to complement each other, thereby improving the overall cleaning effect. Oxalic acid is a strong organic acid with strong corrosiveness and oxidizing properties, and can effectively remove oxides and dirt on the surface of the circuit board. At the same time, oxalic acid can also form complexes with metal ions to prevent metal ions from corroding the circuit board. Citric acid is a weak organic acid with good solubility and stability, and can effectively remove oil and other organic matter without damaging the surface of the circuit board. In addition, citric acid also has a chelating effect, which can form a stable complex with metal ions to prevent metal ions from corroding the circuit board. Glycine is an amino acid with good biocompatibility and biodegradability, which can improve the environmental performance of the cleaning agent. At the same time, glycine also has certain corrosion inhibition properties, which can protect the surface of the circuit board from corrosion. In summary, the synergistic effect between oxalic acid, citric acid and glycine is mainly reflected in the following aspects: oxalic acid and citric acid work together to exert strong oxidizing and solubility, effectively removing oxides and dirt on the surface of the circuit board; oxalic acid and citric acid form a synergistic effect with glycine to improve the cleaning effect; glycine has corrosion inhibition properties to prevent metal ions from corroding the circuit board; the combination of the three organic acids makes the cleaning agent have good stability at both high and low temperatures.

[0010] Preferably, the corrosion inhibitor is composed of 1-butyl-3-methylimidazolium tetrafluoroborate, terephthalaldehyde and mercaptobenzothiazole in a mass ratio of 5:3:4.

[0011] By adopting the above technical scheme, 1-butyl-3-methylimidazolium tetrafluoroborate has good thermal stability and chemical stability, can remain stable during the cleaning process, and is not easy to decompose or volatilize, thereby ensuring the long-term effectiveness and safety of the cleaning agent. In addition, it also has good solubility and low toxicity, which helps to improve cleaning efficiency and reduce environmental impact. Terephthalaldehyde can form a stable complex with the metal surface, thereby preventing the release of metal ions and slowing down the metal corrosion process. At the same time, it can also react with the dirt on the surface of the circuit board to help remove oil and other pollutants. Mercaptobenzothiazole can form a dense protective film with the metal surface, effectively isolating the metal from contact with the corrosive medium and preventing the metal from further corrosion. In addition, mercaptobenzothiazole can also interact with the active ingredients in the organic acid to reduce its corrosiveness to the metal. The combination of these three components produces a significant synergistic effect: 1-butyl-3-methylimidazolium tetrafluoroborate provides good solubility and stability; terephthalaldehyde enhances the binding force with the metal surface and improves the oil removal effect; mercaptobenzothiazole further strengthens the protective ability of the metal surface. This synergistic effect allows the cleaning agent to maintain efficient degreasing while also effectively protecting the circuit board from corrosion and extending its service life.

[0012] Preferably, the surfactant is composed of fatty alcohol polyoxyethylene ether, sodium lauryl sulfate and sodium lauryl polyether sulfate in a mass ratio of 5:2:7.

[0013] By adopting the above technical scheme, the role of surfactants in cleaning agents is mainly to reduce the surface tension of water, improve the wetting and penetration ability of cleaning agents on oil stains, and thus improve the cleaning effect. Fatty alcohol polyoxyethylene ether (AEO): This is a non-ionic surfactant with good emulsification, dispersing and solubilizing properties. It can form a stable emulsion with oil stains, making the oil stains easy to be wrapped by the cleaning agent and removed from the metal surface. In addition, AEO also has a certain corrosion inhibition effect, which can protect the metal surface from corrosion. Sodium dodecyl sulfate (SDS): This is an anionic surfactant with strong detergency and a low critical micelle concentration. SDS can effectively reduce the surface tension of water and improve the wetting and penetration ability of cleaning agents on oil stains. At the same time, SDS also has a certain emulsification and dispersing effect, which helps to disperse the oil stains in water and form a stable emulsion. Sodium lauryl polyether sulfate (LESS): This is also an anionic surfactant with excellent detergency and a low critical micelle concentration. LESS can produce a synergistic effect with fatty alcohol polyoxyethylene ether and sodium dodecyl sulfate, further improving the cleaning agent's decontamination ability and stability. In addition, LESS also has a certain corrosion inhibition effect, which can protect the metal surface from corrosion. In summary, the synergistic effect between fatty alcohol polyoxyethylene ether, sodium dodecyl sulfate and sodium lauryl polyether sulfate is mainly reflected in the following aspects: Reduce the surface tension of water: The three surfactants work together to make the cleaning agent have a lower surface tension, which is beneficial to improve the cleaning agent's wetting and penetration ability on oil stains. Improve detergency: The three surfactants each have excellent decontamination performance, and they produce a synergistic effect with each other, making the cleaning agent have stronger detergency. Improve stability: The three surfactants work together to make the cleaning agent have good stability at both high and low temperatures, which is beneficial to ensure the cleaning effect.

[0014] Preferably, the complexing agent is disodium hydroxyethylidene diphosphonate, and the defoaming agent is a silicone oil defoaming agent.

[0015] Preferably, the stabilizer is composed of neopentyl glycol dibenzoate and aminotrimethylene phosphonic acid in a mass ratio of 3:2.

[0016] By adopting the above technical scheme, the stabilizer is composed of neopentyl glycol dibenzoate and aminotrimethylene phosphonic acid in a mass ratio of 3:2. The two components work together to provide a good emulsification and stabilization effect for the cleaning agent. Neopentyl glycol dibenzoate has good emulsification performance and stability. It can reduce the tension of the oil-water interface, so that the grease forms tiny emulsion droplets in the water, which can be easily washed away. In addition, neopentyl glycol dibenzoate also has a certain solubility and can dissolve some difficult-to-remove dirt. Aminotrimethylene phosphonic acid is an organic phosphine compound. During the cleaning process, it can form a protective film with the metal surface to prevent the metal from being corroded. At the same time, aminotrimethylene phosphonic acid can also synergize with neopentyl glycol dibenzoate to improve the emulsification performance and stability of the cleaning agent. In summary, the synergistic effect between neopentyl glycol dibenzoate and aminotrimethylene phosphonic acid is mainly reflected in the following aspects: Improving emulsification performance: The two work together to better emulsify the grease into tiny emulsion droplets for easy cleaning. Enhanced stability: The presence of aminotrimethylenephosphonic acid can improve the stability of the cleaning agent and prevent the reaggregation of emulsified grease.

[0017] Preferably, the preparation method of the asparagine-choline ionic liquid is as follows: according to the mass fraction, under the stirring condition of 1° C., 100 parts of an aqueous solution of choline hydroxide with a mass concentration of 121 g / L are slowly added dropwise to 200 parts of an aqueous solution of D-asparagine with a mass concentration of 66 g / L, and after the dropwise addition is completed, the solution is neutralized and reacted for 40 hours under stirring conditions at room temperature, and after the reaction, the solution is vacuum dried and dehydrated, and then acetonitrile is used as a solvent for redissolution, and the acetonitrile is removed under reduced pressure, and finally vacuum dried and placed in a dryer for standby use to obtain the asparagine-choline ionic liquid.

[0018] By adopting the above technical scheme, the prepared asparagine-choline ionic liquid has rich functional groups and action sites, which can effectively improve the wettability of the metal surface of the circuit board, making it easier for the cleaning agent to contact the metal surface, thereby improving the degreasing effect. The asparagine-choline ionic liquid forms a protective film on the metal surface of the circuit board, reducing the corrosion ability of organic acids on the surface metal and protecting the surface of the circuit board from corrosion. The asparagine-choline ionic liquid can utilize its rich functional groups and action sites to enhance the wetting of the metal surface of the circuit board and slow down the corrosion of the metal surface, thereby achieving degreasing while improving the decontamination effect. During the preparation process of the asparagine-choline ionic liquid, the ammonia nitrogen content of each component is low, which meets the requirements of green and environmentally friendly production and is beneficial to environmental protection. The asparagine-choline ionic liquid has good stability at high and low temperatures, which is beneficial to the use of cleaning agents under different temperature conditions. Asparagine-choline ionic liquid works together with other ingredients (such as organic acids, monoethanolamine, chelating agents, corrosion inhibitors, surfactants, stabilizers, defoaming agents, etc.) to improve the overall performance of the cleaning agent, making it have a fast and excellent oil removal effect, a detergency of more than 99.89%, and will not corrode the metal on the surface of the circuit board.

[0019] In a second aspect, the present application provides a method for preparing a high-efficiency acid cleaning agent, using the following technical solution: As a general technical concept, the present application also provides a method for preparing the above-mentioned high-efficiency acid cleaning agent, comprising the following steps: S91. Add organic acid, monoethanolamine, asparagine-choline ionic liquid, corrosion inhibitor and complexing agent to deionized water in order according to their weight proportions, mix well, and heat to 50° C. to obtain a mixed solution A. S92. Add surfactant, defoamer and stabilizer to mixed solution A according to their mass fractions, stir the reaction for 2-3 hours at a stirring rate of 150-180 r / min to obtain a high-efficiency acid cleaning agent.

[0020] In a third aspect, the present application provides an application of a high-efficiency acid cleaning agent, using the following technical solution: As a general technical concept, the present application also provides the application of the above-mentioned high-efficiency acid cleaning agent, which is used for cleaning PCB circuit boards. After the high-efficiency acid cleaning agent is diluted with deionized water to 10-12 times, it is stirred evenly, heated to 25-35°C, and ultrasonically cleaned for 60-300 seconds.

[0021] In summary, the beneficial technical effects of this application are: 1. Fast and excellent degreasing effect: The cleaning agent of this application can quickly remove the oil stains on the surface of the circuit board, and the degreasing power reaches 100%.

[0022] 2. No corrosion to the metal on the surface of the circuit board: The cleaning agent of the present application will not corrode the metal on the surface of the circuit board during use, thus protecting the integrity of the circuit board.

[0023] 3. Good stability under high and low temperatures: The cleaning agent of the present application can maintain stable performance under high and low temperature environments and is suitable for cleaning operations under various temperature conditions.

[0024] 4. The preparation method is simple and the production cost is low: The preparation process of the cleaning agent of the present application is simple and the cost of the raw materials required is low, which is conducive to reducing the production cost.

[0025] 5. Comply with green and environmentally friendly production requirements: The ammonia nitrogen content of each component of the cleaning agent of this application is low, which is beneficial to environmental protection and meets the requirements of green and environmentally friendly production.

[0026] 6. Suitable for degreasing and cleaning in various processes of electroplating processing of various types of circuit boards: The cleaning agent of this application has good versatility and can be used for degreasing and cleaning operations in the electroplating process of various types of circuit boards. DETAILED DESCRIPTION

[0027] The embodiments of the present application will be described in detail below in conjunction with the examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present application and should not be considered as limiting the scope of the present application. In the examples, if specific conditions are not specified, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0028] In the following examples, 1 portion means 100 g.

[0029] Preparation Example 1 Preparation of asparagine-choline ionic liquid The preparation method of asparagine-choline ionic liquid is as follows: according to the mass fraction, 1 kg of choline hydroxide aqueous solution with a mass concentration of 121 g / L is slowly added dropwise to 2 kg of D-asparagine aqueous solution with a mass concentration of 66 g / L under stirring conditions at 1°C, and after the addition is completed, the solution is neutralized and reacted for 40 hours under stirring conditions at room temperature, and after the reaction, the solution is vacuum dried and dehydrated, and then acetonitrile is used as a solvent for redissolution, and the acetonitrile is removed under reduced pressure, and finally vacuum dried and placed in a dryer for standby use to obtain asparagine-choline ionic liquid.

[0030] Example 1 A high-efficiency acid cleaning agent, comprising the following raw materials by weight: 22 parts of organic acid, 4 parts of monoethanolamine, 2 parts of disodium hydroxyethylidene diphosphonate, 1 part of corrosion inhibitor, 5 parts of surfactant, 10 parts of stabilizer, 5 parts of asparagine-choline ionic liquid, 0.1 part of defoamer, and 80 parts of deionized water, wherein the organic acid is oxalic acid, the corrosion inhibitor is composed of 1-butyl-3-methylimidazole tetrafluoroborate, terephthalaldehyde and mercaptobenzothiazole in a weight ratio of 5:3:4, the surfactant is composed of fatty alcohol polyoxyethylene ether, sodium dodecyl sulfate and sodium lauryl polyether sulfate in a weight ratio of 5:2:7, and the stabilizer is composed of neopentyl glycol dibenzoate and aminotrimethylene phosphonic acid in a weight ratio of 3:2; The preparation method of the above-mentioned high-efficiency acid cleaning agent comprises the following steps: S91. Add organic acid, monoethanolamine, asparagine-choline ionic liquid, corrosion inhibitor and disodium hydroxyethylidene diphosphonate to deionized water in order according to their weight proportions, mix well, and heat to 50° C. to obtain a mixed solution A. S92. Add surfactant, silicone oil defoamer and stabilizer to mixed solution A according to their mass fractions, stir the reaction for 2 hours at a stirring rate of 180 r / min to obtain a high-efficiency acid cleaning agent.

[0031] Example 2 A high-efficiency acid cleaning agent, comprising the following raw materials by weight: 28 parts of organic acid, 6 parts of monoethanolamine, 3 parts of disodium hydroxyethylidene diphosphonate, 3 parts of corrosion inhibitor, 8 parts of surfactant, 12 parts of stabilizer, 7 parts of asparagine-choline ionic liquid, 0.2 parts of defoamer, and 100 parts of deionized water, wherein the organic acid is citric acid, the corrosion inhibitor is composed of 1-butyl-3-methylimidazole tetrafluoroborate, terephthalaldehyde and mercaptobenzothiazole in a weight ratio of 5:3:4, the surfactant is composed of fatty alcohol polyoxyethylene ether, sodium dodecyl sulfate and sodium lauryl polyether sulfate in a weight ratio of 5:2:7, and the stabilizer is composed of neopentyl glycol dibenzoate and aminotrimethylene phosphonic acid in a weight ratio of 3:2; The preparation method of the above-mentioned high-efficiency acid cleaning agent comprises the following steps: S91. Add organic acid, monoethanolamine, asparagine-choline ionic liquid, corrosion inhibitor and disodium hydroxyethylidene diphosphonate to deionized water in order according to their weight proportions, mix well, and heat to 50° C. to obtain a mixed solution A. S92. Add surfactant, silicone oil defoamer and stabilizer to mixed solution A according to their mass fractions, stir the reaction for 3 hours at a stirring rate of 150 r / min to obtain a high-efficiency acid cleaning agent.

[0032] Example 3 A high-efficiency acid cleaning agent, comprising the following raw materials by weight: 25 parts of organic acid, 5 parts of monoethanolamine, 2.5 parts of disodium hydroxyethylidene diphosphonate, 2 parts of corrosion inhibitor, 7 parts of surfactant, 11 parts of stabilizer, 6 parts of asparagine-choline ionic liquid, 0.15 parts of defoamer, and 90 parts of deionized water, wherein the organic acid is glycine, the corrosion inhibitor is composed of 1-butyl-3-methylimidazole tetrafluoroborate, terephthalaldehyde and mercaptobenzothiazole in a weight ratio of 5:3:4, the surfactant is composed of fatty alcohol polyoxyethylene ether, sodium dodecyl sulfate and sodium lauryl polyether sulfate in a weight ratio of 5:2:7, and the stabilizer is composed of neopentyl glycol dibenzoate and aminotrimethylene phosphonic acid in a weight ratio of 3:2; The preparation method of the above-mentioned high-efficiency acid cleaning agent comprises the following steps: S91. Add organic acid, monoethanolamine, asparagine-choline ionic liquid, corrosion inhibitor and disodium hydroxyethylidene diphosphonate to deionized water in order according to their weight proportions, mix well, and heat to 50° C. to obtain a mixed solution A. S92. Add surfactant, silicone oil defoamer and stabilizer to mixed solution A according to their mass fractions, stir the reaction for 2.5 hours at a stirring rate of 170 r / min to obtain a high-efficiency acid cleaning agent.

[0033] Example 4 The same as Example 3, except that the organic acid is composed of oxalic acid, citric acid and glycine in a mass ratio of 4:3:3.

[0034] Comparative Example 1 The same as Example 4, except that the corrosion inhibitor is 1-butyl-3-methylimidazolium tetrafluoroborate.

[0035] Comparative Example 2 The same as Example 4, except that the corrosion inhibitor is terephthalaldehyde.

[0036] Comparative Example 3 The same as Example 4, except that the corrosion inhibitor is mercaptobenzothiazole.

[0037] Comparative Example 4 The same as Example 4, except that the surfactant is fatty alcohol polyoxyethylene ether.

[0038] Comparative Example 5 The same as Example 4, except that the surfactant is sodium dodecyl sulfate.

[0039] Comparative Example 6 The same as Example 4, except that the surfactant is sodium lauryl polyether sulfate.

[0040] Comparative Example 7 The same as Example 4, except that the stabilizer is neopentyl glycol dibenzoate.

[0041] Comparative Example 8 The same as Example 4, except that the stabilizer is aminotrimethylenephosphonic acid.

[0042] Comparative Example 9 The same as Example 4, except that the amount of asparagine-choline ionic liquid added is 0 parts.

[0043] Performance Testing The PCB circuit board samples after chemical nickel plating were cut into 5cm×5cm samples, and then sandpaper was used to remove the roughness of the corners. In addition to conventional oil stains, the surface of the processed circuit board was also attached with relatively uniform glue marks, fingerprints, oil stains, oxidation points and other difficult-to-remove pollutants. After the sample was processed, 1kg of high-efficiency acid cleaning agent prepared by Example 1-Example 4 and Comparative Example 1-Comparative Example 9 was diluted with deionized water to 11kg of acid cleaning liquid to degrease the PCB circuit board samples. The degreasing process was to immerse the PCB circuit board sample in the acid cleaning liquid with a pre-adjusted temperature (30°C), take it out after reaching a predetermined time (300s), and then use deionized water and ethanol to clean for 60s in succession, and then dry it for subsequent performance index evaluation. The test results are shown in Table 1.

[0044] Detergency: Tested in accordance with QB / T 4313-2012; Cleanliness evaluation: 10-point scoring system. Determine whether there are fingerprints, oxidation spots, oil stains and other stubborn stains on the surface of the circuit board after the acid cleaning agent treatment. Among them, 10 points is the best, which means that after the acid cleaning agent treatment, there are no fingerprints, oxidation spots, oil stains and other stains on the surface of the circuit board; 8-9, 5-7, 2-4 points respectively mean that after the acid cleaning agent treatment, there are very few, a small amount or a large number of fingerprints, oxidation spots, oil stains and other stains on the surface of the circuit board; 0 points is the worst, which means that after the treatment, there are a large number of obvious fingerprints, oxidation spots, oil stains and other stains on the surface of the circuit board.

[0045] Corrosion performance evaluation: 10-point scoring system. Determine whether there is corrosion on the surface of the circuit board after the cleaning agent treatment. Among them, 10 points is the best, which means that there is no corrosion on the surface of the circuit board after the acid cleaning agent treatment; 8-9, 5-7, and 2-4 points respectively mean that there is very little, a small amount, and a large amount of corrosion on the surface of the circuit board after the acid cleaning agent treatment; 0 points is the worst, which means that there is a lot of corrosion on the surface of the circuit board after treatment.

[0046] High temperature stability: Place the solution at 60±2℃ for 72h. Requirements: uniformity and no stratification.

[0047] Low temperature stability: Place the solution in -5±2℃ environment for 72h. Requirements: uniformity and no stratification.

[0048] Table 1 Performance test Analyzing the data in Table 1, we can see that: 1) The high-efficiency acid cleaning agent prepared in Examples 1 to 4 has a fast and excellent oil removal effect, a detergency of more than 99.89%, will not corrode the metal surface of the circuit board during use, and the cleaning agent has good stability at high and low temperatures. The preparation method of the present application is simple, the production cost is low, it meets the requirements of green and environmentally friendly production, and is suitable for the oil removal and cleaning of various processes of electroplating processing of various types of circuit boards.

[0049] 2) The performance comparison analysis of the high-efficiency acid cleaning agent prepared in combination with Example 4 and Example 3 shows that the organic acid is composed of oxalic acid, citric acid and glycine in a mass ratio of 4:3:3. This combination makes the advantages of various acids complementary, thereby improving the overall cleaning effect. By utilizing the synergistic effect between them, oxalic acid and citric acid jointly exert strong oxidizing properties and solubility to effectively remove oxides and dirt on the surface of the circuit board; oxalic acid and citric acid form a synergistic effect with glycine to improve the cleaning effect; glycine has corrosion inhibition properties to prevent metal ions from corroding the circuit board; the combination of the three organic acids makes the cleaning agent have good stability at both high and low temperatures.

[0050] 3) The performance comparison analysis of the high-efficiency acid cleaning agents prepared in combination with Example 4 and Comparative Examples 1 to 3 shows that the corrosion inhibitor is composed of 1-butyl-3-methylimidazolium tetrafluoroborate, terephthalaldehyde and mercaptobenzothiazole in a mass ratio of 5:3:4. By utilizing the synergistic effect between them, the cleaning agent can effectively protect the circuit board from corrosion while maintaining efficient degreasing, thereby extending its service life.

[0051] 4) The performance comparison analysis of the high-efficiency acidic cleaning agent prepared in combination with Example 4 and Comparative Examples 4 to Comparative Examples 6 shows that the surfactant is composed of fatty alcohol polyoxyethylene ether, sodium lauryl sulfate and sodium lauryl polyether sulfate in a mass ratio of 5:2:7. The synergistic effect between them is used to reduce the surface tension of water, improve the wetting and penetration ability of the cleaning agent on oil stains, and thus improve the cleaning effect. The cleaning agent has a lower surface tension, which is conducive to improving the wetting and penetration ability of the cleaning agent on oil stains.

[0052] 5) The performance comparison analysis of the high-efficiency acidic cleaning agents prepared in combination with Example 4 and Comparative Examples 7-8 shows that the stabilizer is composed of neopentyl glycol dibenzoate and aminotrimethylene phosphonic acid in a mass ratio of 3:2. The two components work synergistically to better emulsify the grease into tiny emulsion droplets, which is convenient for cleaning and provides good emulsification and stabilization effects for the cleaning agent.

[0053] 6) The performance comparison analysis of the high-efficiency acidic cleaning agent prepared in combination with Example 4 and Comparative Example 9 shows that the asparagine-choline ionic liquid prepared in the present application has abundant functional groups and action sites, which can effectively improve the wettability of the metal surface of the circuit board, making it easier for the cleaning agent to contact the metal surface, thereby improving the degreasing effect. The asparagine-choline ionic liquid forms a protective film on the metal surface of the circuit board, reduces the corrosion ability of organic acids on the surface metal, and protects the surface of the circuit board from corrosion. The asparagine-choline ionic liquid can utilize its abundant functional groups and action sites to enhance the wetting of the metal surface of the circuit board and slow down the corrosion of the metal surface, thereby achieving the improvement of the decontamination effect while achieving degreasing. The asparagine-choline ionic liquid has good stability at high and low temperatures, which is conducive to the use of the cleaning agent under different temperature conditions. The asparagine-choline ionic liquid works together with other ingredients (such as organic acids, monoethanolamine, complexing agents, corrosion inhibitors, surfactants, stabilizers, defoamers, etc.) to improve the overall performance of the cleaning agent, so that it has a fast and excellent degreasing effect, and will not corrode the metal on the surface of the circuit board.

[0054] The above embodiments are only used to explain the technical solutions of the present application rather than to limit them. Although the above embodiments provide a specific description of the present application, relevant technical personnel should understand that the specific implementation modes of the present invention can still be modified or replaced by equivalents, and any modifications and equivalent replacements that do not depart from the spirit and scope of the present application should be included in the scope of protection of the present application.

Claims

1. A high-efficiency acid cleaning agent, characterized in that: The preparation raw materials include the following by weight: 22-28 parts of organic acid, 4-6 parts of monoethanolamine, 2-3 parts of complexing agent, 1-3 parts of corrosion inhibitor, 5-8 parts of surfactant, 10-12 parts of stabilizer, 5-7 parts of asparagine-choline ionic liquid, 0.1-0.2 parts of defoaming agent and 80-100 parts of deionized water.

2. A high-efficiency acid cleaning agent according to claim 1, characterized in that: The organic acid is at least one of oxalic acid, citric acid and glycine.

3. A high-efficiency acid cleaning agent according to claim 2, characterized in that: The organic acid consists of oxalic acid, citric acid and glycine in a mass ratio of 4:3:

3.

4. A high-efficiency acid cleaning agent according to claim 1, characterized in that: The corrosion inhibitor is composed of 1-butyl-3-methylimidazole tetrafluoroborate, terephthalaldehyde and mercaptobenzothiazole in a mass ratio of 5:3:

4.

5. A high-efficiency acid cleaning agent according to claim 1, characterized in that: The surfactant is composed of fatty alcohol polyoxyethylene ether, sodium lauryl sulfate and sodium lauryl polyether sulfate in a mass ratio of 5:2:

7.

6. A high-efficiency acid cleaning agent according to claim 1, characterized in that: The complexing agent is disodium hydroxyethylidene diphosphonate, and the defoaming agent is a silicone oil defoaming agent.

7. A high-efficiency acid cleaning agent according to claim 1, characterized in that: The stabilizer is composed of neopentyl glycol dibenzoate and aminotrimethylene phosphonic acid in a mass ratio of 3:

2.

8. A high-efficiency acid cleaning agent according to claim 1, characterized in that: The preparation method of the asparagine-choline ionic liquid is as follows: according to the mass fraction, under the stirring condition of 1° C., 100 parts of a choline hydroxide aqueous solution with a mass concentration of 121 g / L are slowly added dropwise to 200 parts of a D-asparagine aqueous solution with a mass concentration of 66 g / L; after the addition is completed, neutralization reaction is carried out under stirring condition at room temperature for 40 hours; after the reaction, vacuum drying and dehydration are carried out; acetonitrile is used as a solvent for redissolution; the acetonitrile is removed under reduced pressure; finally, vacuum drying is carried out, and the solution is placed in a desiccator for standby use, thereby obtaining the asparagine-choline ionic liquid.

9. A method for preparing a high-efficiency acid cleaning agent according to any one of claims 1 to 8, characterized in that: The following steps are involved: S91. Add organic acid, monoethanolamine, asparagine-choline ionic liquid, corrosion inhibitor and complexing agent to deionized water in order according to their weight proportions, mix well, and heat to 50° C. to obtain a mixed solution A. S92. Add surfactant, defoamer and stabilizer to mixed solution A according to their mass fractions, stir the reaction for 2-3 hours at a stirring rate of 150-180 r / min to obtain a high-efficiency acid cleaning agent.

10. Use of a high-efficiency acid cleaning agent according to any one of claims 1 to 8, characterized in that: The invention is applied to cleaning PCB circuit boards. The high-efficiency acid cleaning agent is diluted with deionized water to 10-12 times, stirred evenly, heated to 25-35° C., and ultrasonically cleaned for 60-300 seconds.

Images