Efficient environment-friendly acidic degreaser and preparation method thereof

Abstract

The invention relates to the technical field of circuit board processing, in particular to an efficient environment-friendly acidic degreaser and a preparation method thereof. An efficient environment-friendly acidic degreasing agent is prepared from the following preparation raw materials in parts by mass: 30-40 parts of inorganic acid, 12-15 parts of a corrosion inhibitor, 40-50 parts of a wetting agent, 10-12 parts of an emulsion stabilizer, 8-10 parts of isoeugenol, 15-18 parts of plant degreasing liquid and 850-870 parts of deionized water. The efficient and environment-friendly acidic degreaser has a rapid and excellent degreasing effect, can effectively protect metal on the surface of a circuit board and improve the binding force of a plating layer, has the characteristics of good high and low temperature stability, environmental protection, simple preparation method, low production cost, excellent comprehensive performance and the like, and is suitable for electroplating acidic degreasing procedures of various circuit boards.

Description

Technical Field

[0001] The present application relates to the technical field of circuit board processing, and in particular to a highly efficient and environmentally friendly acidic degreasing agent and a preparation method 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, a layer of oil will inevitably adhere to the copper surface, and at the same time it will be contaminated by fingerprints, oil stains, glue marks, oxidation points, etc. If it is not effectively removed, it will affect the quality of the subsequent processing coating or conversion film and reduce the yield rate of circuit board products. Therefore, it is necessary to pre-treat the PCB board to remove oil.

[0004] There are some existing technologies for acidic degreasing of circuit boards. Patent CN112064050B discloses an acidic degreasing agent for electroplating copper and its preparation method. The main components are: 120-160g / L oxalic acid, 30-50g / L citric acid, 10-50g / L potassium salicylate, 8-20g / L sodium sulfate, 6-10g / L surfactant, 2-5g / L emulsifier stabilizer, 13g / L disodium ethylenediaminetetraacetic acid. The acidic degreasing agent is easy to wash with water; it can quickly remove fingerprints, oil stains and oxides on the surface of the electroplated substrate, has a high degreasing rate, good rust prevention performance, low corrosion performance on the metal substrate, and can effectively improve the bonding strength of the coating.

[0005] Patent CN112877143A discloses a method for preparing an acidic degreasing agent for PCB circuit boards. The raw materials include: 80-100 parts of deionized water, 22-34 parts of cycloalkanes, 18-30 parts of ethanol, 10-20 parts of organic amine esters, 5-10 parts of emulsifiers, 10-20 parts of metal cleaning agents and 4-8 parts of surfactants. The acidic degreasing agent has an excellent degreasing effect. At the same time, the ethanol solution in the components can not only disinfect the surface of the PCB circuit board, but also the ethanol is volatile and can accelerate the air-drying time of the moisture on the surface of the PCB circuit board, thereby improving the work efficiency. However, the ethanol is volatile, and the proportion of the content of each component in the solution will change, and the effect cannot be sustained.

[0006] The existing technology has a certain degreasing effect, but it still has disadvantages: 1) The acidity of organic acids such as oxalic acid and citric acid is generally weak, and it is difficult to achieve the effect of rust removal, oil removal and oxide removal. A larger concentration of organic acid is required to have a significant degreasing effect, which increases the material cost; 2) Amine compounds are often added to acidic degreasing agents as additives to improve the degreasing effect, but their ammonia nitrogen content is high and can easily cause pollution; therefore, researchers have also developed some more environmentally friendly degreasing agents, but the industrial process is complicated and costly, and is not suitable for modern industrial production. Summary of the invention

[0007] The purpose of the present application is to provide an efficient and environmentally friendly acidic degreasing agent and a preparation method thereof in view of the deficiencies in the current technology. The efficient and environmentally friendly acidic degreasing agent prepared in the present application has a fast and excellent degreasing effect, will not corrode the metal on the surface of the circuit board during use, can effectively improve the bonding strength of the coating, and the degreasing agent has good stability at high and low temperatures. The preparation method is simple, the production cost is low, the ammonia nitrogen content of each component is low, and it meets the requirements of green and environmentally friendly production and satisfies the acidic degreasing process for electroplating of various circuit boards.

[0008] In the first aspect, the present application provides a highly efficient and environmentally friendly acidic degreasing agent, which adopts the following technical solution: A highly efficient and environmentally friendly acidic degreasing agent comprises the following raw materials, measured by weight: 30-40 parts of inorganic acid, 12-15 parts of corrosion inhibitor, 40-50 parts of wetting agent, 10-12 parts of emulsifier stabilizer, 8-10 parts of isoeugenol, 15-18 parts of plant degreasing liquid and 850-870 parts of deionized water.

[0009] By adopting the above technical scheme, the high-efficiency and environmentally friendly acidic degreasing agent of the present application achieves a fast and excellent degreasing effect through the synergistic effect of inorganic acid, corrosion inhibitor, wetting agent, emulsifier stabilizer, isoeugenol, plant degreasing liquid and deionized water, while avoiding corrosion of the metal on the surface of the circuit board and improving the bonding strength of the coating. Inorganic acid can dissolve and remove fingerprints, grease and oxides on the copper surface; corrosion inhibitor forms a stable acid-resistant adsorption protective film on the metal surface, reducing the corrosion ability of inorganic acid on the surface metal; wetting agent reduces the surface tension or interfacial tension of the solution, so that the surface of the circuit board can be wetted by the solution, improving the degreasing performance; emulsifier stabilizer can be adsorbed on the interface of oil and water, so that the gravitational force between the oil stains on the surface of the circuit board and the surface of the circuit board is gradually weakened, and the oil stains on the surface of the circuit board can easily become dispersed small oil droplets, detach from the surface of the circuit board, and enter the solution; isoeugenol has a dissolving and dispersing effect on oil, accelerates the degreasing rate, and improves the degreasing effect; plant degreasing liquid is extracted from the plant liquid of orange peel and lemon peel, fully mixed with citric acid, and the plant liquid is used to separate oil and improve the efficiency of degreasing and cleaning. Therefore, the high-efficiency and environmentally friendly acidic degreasing agent of the present application not only has excellent degreasing performance, but also meets the requirements of green and environmentally friendly production, and meets the acidic degreasing process of electroplating of various circuit boards.

[0010] Preferably, the inorganic acid is composed of 98% sulfuric acid and 37% hydrochloric acid in a mass ratio of 4:1-2.

[0011] Preferably, the corrosion inhibitor is composed of β-cyclocitral, terephthalaldehyde and mercaptobenzothiazole in a mass ratio of 5:3:2.

[0012] By adopting the above technical scheme, the corrosion inhibitor is composed of β-cyclocitral, terephthalaldehyde and mercaptobenzothiazole in a mass ratio of 5:3:2, and its function is to form a stable acid-resistant adsorption type protective film on the surface of the circuit board to reduce the corrosion ability of inorganic acids to the surface metal. β-cyclocitral has good antioxidant properties and can effectively prevent the oxidation of the metal on the surface of the circuit board, thereby protecting the conductive properties of the circuit board. Terephthalaldehyde has good corrosion resistance and can form a stable protective film on the surface of the circuit board to prevent the corrosion of the metal on the surface of the circuit board by inorganic acids. Mercaptobenzothiazole has good adsorption properties and can be effectively adsorbed on the surface of the circuit board to form a uniform protective film. The synergistic effect of these three substances enables the corrosion inhibitor to form a uniform, stable, acid-resistant protective film on the surface of the circuit board, effectively preventing the corrosion of the metal on the surface of the circuit board by inorganic acids, and improving the service life of the circuit board.

[0013] Preferably, the wetting agent is composed of lauryl polyoxyethylene ether, dodecyl ethoxy sulfobetaine and asparagine-choline ionic liquid in a mass ratio of 4:7:3.

[0014] By adopting the above technical scheme, the wetting agent is composed of lauryl polyoxyethylene ether, dodecyl ethoxy sulfobetaine and asparagine-choline ionic liquid in a mass ratio of 4:7:3, and its main function is to reduce the surface tension or interfacial tension of the solution, so that the medicine can better wet the surface of the circuit board, thereby improving the degreasing performance. Lauryl polyoxyethylene ether has good surface activity, which can effectively reduce the surface tension of the solution, so that the medicine can better wet the surface of the circuit board. Dodecyl ethoxy sulfobetaine has good emulsifying properties, which can disperse oil stains into small oil droplets, making it easier to detach from the surface of the circuit board. Asparagine-choline ionic liquid has good penetration properties, which can penetrate into the micropores on the surface of the circuit board and remove the oil stains from the micropores. The synergistic effect of these three substances enables the wetting agent to better wet the surface of the circuit board, disperse the oil stains into small oil droplets, and remove them from the micropores, thereby improving the degreasing performance.

[0015] 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., a choline hydroxide aqueous solution with a mass concentration of 121 g / L is slowly added dropwise to an aqueous solution of D-asparagine with a mass concentration of 66 g / L; after the addition is completed, the solution is neutralized under stirring conditions at room temperature for 36-48 hours; after the reaction, the solution is vacuum dried and dehydrated; acetonitrile is used as a solvent for redissolution; the acetonitrile is removed under reduced pressure; and finally, the solution is vacuum dried and placed in a dryer for standby use to obtain the asparagine-choline ionic liquid.

[0016] By adopting the above technical scheme, asparagine-choline ionic liquid has abundant functional groups and action sites, which can effectively improve the wettability of the copper surface of the circuit board, making it easier for the degreasing agent to contact the copper surface, thereby improving the degreasing effect. Asparagine-choline ionic liquid forms a protective film on the copper surface of the circuit board, reducing the corrosion ability of inorganic acids on the surface metal, and protecting the surface of the circuit board from corrosion. Asparagine-choline ionic liquid can utilize its abundant functional groups and action sites to enhance the wetting of the copper surface of the circuit board and slow down the corrosion of the copper surface, thereby achieving degreasing while improving the decontamination effect. During the preparation process of 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. In summary, asparagine-choline ionic liquid plays an important role in this application, improves the performance and use effect of the degreasing agent, and meets the needs of acid degreasing processes for electroplating of various circuit boards.

[0017] Preferably, the mass ratio of the aqueous solution of choline hydroxide with a mass concentration of 121 g / L to the aqueous solution of D-asparagine with a mass concentration of 66 g / L is 1:2.

[0018] Preferably, the emulsion stabilizer is composed of neopentyl glycol dibenzoate and triethanolamine oleic acid soap in a mass ratio of 3:5.

[0019] By adopting the above technical scheme, neopentyl glycol dibenzoate is a nonionic surfactant with good emulsification, dispersing and wetting properties. It can reduce the surface tension or interfacial tension of the solution, so that when the potion contacts the surface of the circuit board, the lipophilic group adheres to the board surface, and the hydrophilic group extends outward into the liquid, thereby improving the degreasing performance. At the same time, neopentyl glycol dibenzoate can also maintain the chemical balance between the components, prevent the effects of light, thermal decomposition or oxidative decomposition, thereby improving the stability of the potion at high and low temperatures, so that the potion can maintain an excellent degreasing effect for a long time. Triethanolamine oleic acid soap is an anionic surfactant with good emulsification, washing and antistatic properties. It can be adsorbed on the interface of oil and water, and the hydrophilic group therein can have an affinity with the aqueous solution, while the hydrophobic group has an affinity with the oil on the surface of the circuit board. Under the interaction of these two groups, the gravitational force between the oil stains on the surface of the circuit board and the surface of the circuit board is gradually weakened, and the oil stains on the surface of the circuit board are easily transformed into dispersed small oil droplets, which are separated from the surface of the circuit board and enter the solution. The synergistic effect between neopentyl glycol dibenzoate and triethanolamine oleic acid soap is mainly reflected in the following aspects: Complementarity: neopentyl glycol dibenzoate mainly plays the role of emulsification, dispersion and wetting, while triethanolamine oleic acid soap mainly plays the role of emulsification, washing and antistatic. The combination of the two can give full play to their respective advantages and improve the comprehensive performance of the degreaser. Stability: neopentyl glycol dibenzoate can maintain the chemical balance between the components and prevent light, thermal decomposition or oxidative decomposition, while triethanolamine oleic acid soap can be adsorbed at the interface of oil and water to reduce the corrosion ability of inorganic acid on the surface metal. The combination of the two can improve the stability of the degreaser at high and low temperatures, so that the potion can maintain an excellent degreasing effect for a long time. Economic efficiency: neopentyl glycol dibenzoate and triethanolamine oleic acid soap are both common chemical raw materials with relatively low prices, simple preparation methods and low production costs. The combination of the two can reduce production costs while ensuring the performance of the degreaser and meet the requirements of green and environmentally friendly production.

[0020] Preferably, the method for preparing the plant degreasing liquid comprises the following steps: S81. According to the mass fraction, the washed and dried orange peel and lemon peel are crushed to obtain crushed blocks after crushing to 50 mesh; S82. Add the crushed pieces into a citric acid solution with a mass concentration of 50% according to the mass fraction and boil them. After boiling for 30-40 minutes, filter out the impurities to obtain a plant deoiling liquid.

[0021] By adopting the above technical scheme, the plant degreasing liquid can extract the plant liquid of orange peel and lemon peel, mix and boil it with citric acid, fully mix it with citric acid, and use the plant liquid to separate oil and fat, thereby improving the efficiency of degreasing and cleaning. The plant degreasing liquid uses natural plant raw materials, such as orange peel and lemon peel, which has the characteristics of being renewable and degradable, and meets the requirements of green and environmentally friendly production. The plant degreasing liquid and other components (such as inorganic acids, corrosion inhibitors, wetting agents, emulsifiers and stabilizers, etc.) work together to make the efficient and environmentally friendly acidic degreasing agent have a fast and excellent degreasing effect. It will not corrode the metal on the surface of the circuit board during use, can effectively improve the bonding strength of the coating, and the degreasing agent has good stability at high and low temperatures. In summary, the plant degreasing liquid plays a role in improving the degreasing and cleaning efficiency, green environmental protection, and synergistic effects with other components in the efficient and environmentally friendly acidic degreasing agent, meeting the needs of various types of circuit board electroplating acidic degreasing processes.

[0022] Preferably, the mass ratio of the orange peel, lemon peel and 50% citric acid solution is 1:1:4.

[0023] In the second aspect, the present application provides a method for preparing an efficient and environmentally friendly acidic degreasing agent, using the following technical scheme: As a general technical concept, the present application also provides a method for preparing the above-mentioned efficient and environmentally friendly acidic degreasing agent, comprising the following steps: S101, adding inorganic acid, corrosion inhibitor, plant degreasing liquid and isoeugenol in parts by mass to deionized water, mixing well, and heating to a temperature of 50-60° C. to obtain a mixed solution A; S102, adding a wetting agent and an emulsion stabilizer into the mixed solution A, stirring the reaction for 2-3 hours at a stirring rate of 150-180 r / min, to obtain a highly efficient and environmentally friendly acidic degreasing agent.

[0024] In summary, the beneficial technical effects of this application are: 1. Fast and excellent degreasing effect: Through the synergistic effect of components such as inorganic acid, wetting agent, emulsifier stabilizer and isoeugenol, the high-efficiency and environmentally friendly acidic degreasing agent of the present application can quickly dissolve and remove grease, fingerprints and oxides on the surface of the circuit board, thereby improving the degreasing rate and effect.

[0025] 2. Protect the metal on the surface of the circuit board: The corrosion inhibitor forms a stable acid-resistant adsorption protective film on the metal surface, reducing the corrosion ability of inorganic acids on the surface metal, thereby effectively protecting the metal on the surface of the circuit board and preventing it from being damaged.

[0026] 3. Improve the bonding strength of the coating: Since the degreasing agent of the present application can achieve efficient degreasing without corroding the metal on the surface of the circuit board, it can effectively improve the bonding strength between the coating and the surface of the circuit board after use, thereby improving the quality of the circuit board.

[0027] 4. Good high and low temperature stability: Emulsion stabilizers can maintain the chemical balance between the components, prevent light, thermal decomposition or oxidative decomposition, thereby improving the stability of the potion at high and low temperatures, so that the potion can maintain excellent oil removal effect for a long time.

[0028] 5. Green and environmentally friendly: The degreasing agent of the present application adopts environmentally friendly raw materials, such as plant degreasing liquid, which has a low ammonia nitrogen content, meets the requirements of green and environmentally friendly production, and is beneficial to environmental protection and sustainable development.

[0029] 6. Simple and low-cost preparation method: The degreasing agent preparation method of the present application is simple and has low production cost, which is beneficial to reducing the production cost of the enterprise and improving the competitiveness of the enterprise.

[0030] 7. Wide applicability: It can be used in acid degreasing processes for electroplating of various circuit boards, and has high practical value and market potential. DETAILED DESCRIPTION

[0031] 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. If specific conditions are not specified in the examples, 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.

[0032] 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, 10 kg of choline hydroxide aqueous solution with a mass concentration of 121 g / L is slowly added dropwise to 20 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 under stirring conditions at room temperature for 42 hours, 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.

[0033] Preparation Example 2 Preparation of plant degreasing liquid The method for preparing a plant degreasing liquid comprises the following steps: S81, according to the mass fraction, 10 kg of washed and dried orange peel and 10 kg of washed and dried lemon peel were crushed to 50 mesh to obtain crushed blocks; S82. Add the crushed pieces into 40 kg of 50% citric acid solution according to the mass fraction and boil them. After boiling for 35 minutes, filter out the impurities to obtain a plant deoiling liquid.

[0034] Example 1 A highly efficient and environmentally friendly acidic degreasing agent comprises the following raw materials, measured by weight: 30 kg of inorganic acid, 12 kg of corrosion inhibitor, 40 kg of wetting agent, 10 kg of emulsifier stabilizer, 8 kg of isoeugenol, 15 kg of plant degreasing liquid, and 850 kg of deionized water, wherein the inorganic acid is composed of 98% sulfuric acid and 37% hydrochloric acid in a weight ratio of 4:1, the corrosion inhibitor is composed of β-cyclocitral, terephthalaldehyde and mercaptobenzothiazole in a weight ratio of 5:3:2, the wetting agent is composed of lauryl polyoxyethylene ether, dodecyl ethoxysulfobetaine and asparagine-choline ionic liquid in a weight ratio of 4:7:3, and the emulsifier stabilizer is composed of neopentyl glycol dibenzoate and triethanolamine oleic acid soap in a weight ratio of 3:5.

[0035] The preparation method of the above-mentioned high-efficiency and environmentally friendly acidic degreasing agent comprises the following steps: S101, adding inorganic acid, corrosion inhibitor, plant degreasing liquid and isoeugenol in parts by mass to deionized water, mixing well, and heating to 50° C. to obtain a mixed solution A; S102, adding a wetting agent and an emulsion stabilizer into the mixed solution A, stirring the reaction for 2 hours at a stirring rate of 180 r / min, to obtain a highly efficient and environmentally friendly acidic degreasing agent.

[0036] Example 2 A highly efficient and environmentally friendly acidic degreasing agent comprises the following raw materials, measured by weight: 40 kg of inorganic acid, 15 kg of corrosion inhibitor, 50 kg of wetting agent, 12 kg of emulsifier stabilizer, 10 kg of isoeugenol, 18 kg of plant degreasing liquid, and 870 kg of deionized water, wherein the inorganic acid is composed of sulfuric acid with a mass concentration of 98% and hydrochloric acid with a mass concentration of 37% in a mass ratio of 4:2, the corrosion inhibitor is composed of β-cyclocitral, terephthalaldehyde and mercaptobenzothiazole in a mass ratio of 5:3:2, the wetting agent is composed of lauryl polyoxyethylene ether, dodecyl ethoxy sulfobetaine and asparagine-choline ionic liquid in a mass ratio of 4:7:3, and the emulsifier stabilizer is composed of neopentyl glycol dibenzoate and triethanolamine oleic acid soap in a mass ratio of 3:5.

[0037] The preparation method of the above-mentioned high-efficiency and environmentally friendly acidic degreasing agent comprises the following steps: S101, adding inorganic acid, corrosion inhibitor, plant degreasing liquid and isoeugenol in parts by mass to deionized water, mixing well, and heating to 60° C. to obtain a mixed solution A; S102, adding a wetting agent and an emulsion stabilizer into the mixed solution A, stirring the reaction for 3 hours at a stirring rate of 150 r / min, to obtain a highly efficient and environmentally friendly acidic degreasing agent.

[0038] Example 3 A highly efficient and environmentally friendly acidic degreasing agent comprises the following raw materials, measured by weight: 35 kg of inorganic acid, 14 kg of corrosion inhibitor, 45 kg of wetting agent, 11 kg of emulsifier stabilizer, 9 kg of isoeugenol, 16 kg of plant degreasing liquid, and 860 kg of deionized water, wherein the inorganic acid is composed of 98% sulfuric acid and 37% hydrochloric acid in a weight ratio of 4:1.5, the corrosion inhibitor is composed of β-cyclocitral, terephthalaldehyde and mercaptobenzothiazole in a weight ratio of 5:3:2, the wetting agent is composed of lauryl polyoxyethylene ether, dodecyl ethoxysulfobetaine and asparagine-choline ionic liquid in a weight ratio of 4:7:3, and the emulsifier stabilizer is composed of neopentyl glycol dibenzoate and triethanolamine oleic acid soap in a weight ratio of 3:5.

[0039] The preparation method of the above-mentioned high-efficiency and environmentally friendly acidic degreasing agent comprises the following steps: S101, adding inorganic acid, corrosion inhibitor, plant degreasing liquid and isoeugenol in parts by mass to deionized water, mixing well, and heating to 55° C. to obtain a mixed solution A; S102, adding a wetting agent and an emulsion stabilizer into the mixed solution A, stirring the reaction for 2.5 hours at a stirring rate of 170 r / min, to obtain a highly efficient and environmentally friendly acidic degreasing agent.

[0040] Comparative Example 1 The same as Example 3, except that the corrosion inhibitor is β-cyclocitral.

[0041] Comparative Example 2 The same as Example 3, except that the corrosion inhibitor is terephthalaldehyde.

[0042] Comparative Example 3 The same as Example 3, except that the corrosion inhibitor is mercaptobenzothiazole.

[0043] Comparative Example 4 The same as Example 3, except that the wetting agent is lauryl polyoxyethylene ether.

[0044] Comparative Example 5 The same as Example 3, except that the wetting agent is dodecylethoxysulfobetaine.

[0045] Comparative Example 6 The same as Example 3, except that the wetting agent is asparagine-choline ionic liquid.

[0046] Comparative Example 7 The same as Example 3, except that the emulsion stabilizer is neopentyl glycol dibenzoate.

[0047] Comparative Example 8 The same as Example 3, except that the emulsion stabilizer is triethanolamine oleic acid soap.

[0048] Performance Testing The processed PCB circuit board samples 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 processed circuit board surface was also attached with relatively uniform glue marks, fingerprints, oil stains, oxidation points and other difficult-to-remove pollutants. After the sample was processed, the circuit board samples were degreased using the high-efficiency and environmentally friendly acidic degreasers prepared in Example 1-Example 3 and Comparative Example 1-Comparative Example 8. The degreasing process was to immerse the circuit board sample in the high-efficiency and environmentally friendly acidic degreaser with a pre-adjusted temperature (30°C), take it out after reaching a predetermined time (200s), and then use deionized water and ethanol to clean it for 60s in succession, and then dry it for subsequent performance index evaluation. The test results are shown in Table 1.

[0049] Degreasing effect evaluation: a five-point scoring system. Determine whether there are any light oil residues such as grease film on the surface of the circuit board after the degreasing agent treatment. Among them, 10 points is the best, which means that after the acid degreasing agent treatment, there are no light oil residues such as grease film on the surface of the circuit board; 8-9, 5-7, and 2-4 points respectively mean that after the acid degreasing agent treatment, there are very little, a small amount, and a large amount of light oil residues such as grease film on the surface of the circuit board; 0 points is the worst, which means that after the treatment, there are a lot of light oil residues such as grease film on the surface of the circuit board.

[0050] Cleanliness evaluation: 5-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 degreasing agent treatment. Among them, 10 points is the best, which means that after the acid degreasing 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 degreasing 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.

[0051] Corrosion performance evaluation: a five-point scoring system. Determine whether there is corrosion on the surface of the circuit board after the degreasing 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 degreasing 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 degreasing 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.

[0052] High temperature stability: Place the solution in an environment of 60±2℃ for 24h. Requirements: uniformity and no stratification.

[0053] Low temperature stability: Place the solution in -5±2℃ for 24h. Requirements: uniformity and no stratification.

[0054] Ammonia nitrogen content: Take a small amount of acidic degreasing agent and detect its ammonia nitrogen content using Nessler's reagent photometry. The principle is that alkaline solutions of mercuric iodide and potassium iodide react with ammonia to form a light reddish brown colloidal compound with strong absorption in the wavelength range of 410-425nm.

[0055] Table 1 Performance test Analyzing the data in Table 1, we can see that: 1) The highly efficient and environmentally friendly acidic degreasing agent prepared in Examples 1 to 3 has a fast and excellent degreasing effect, will not corrode the metal on the surface of the circuit board during use, has good stability at high and low temperatures, is simple to prepare, has low production cost, and has low ammonia nitrogen content in each component, which meets the requirements of green and environmentally friendly production and is suitable for the acidic degreasing process of electroplating of various circuit boards.

[0056] 2) The performance comparison analysis of the high-efficiency and environmentally friendly acidic degreasers prepared in combination with Example 3 and Comparative Examples 1 to 3 shows that the corrosion inhibitor is composed of β-cyclocitral, terephthalaldehyde and mercaptobenzothiazole in a mass ratio of 5:3:2. By utilizing the synergistic effect therebetween, the corrosion inhibitor can form a uniform, stable, acid-resistant protective film on the surface of the circuit board, effectively preventing the corrosion of the metal on the surface of the circuit board by inorganic acid, and improving the service life of the circuit board.

[0057] 3) The performance comparison analysis of the high-efficiency and environmentally friendly acidic degreasers prepared in combination with Example 3 and Comparative Examples 4 to 6 shows that the wetting agent is composed of lauryl polyoxyethylene ether, dodecyl ethoxy sulfobetaine and asparagine-choline ionic liquid in a mass ratio of 4:7:3. By utilizing the synergistic effect therebetween, the wetting agent can better wet the surface of the circuit board, disperse the oil into small oil droplets, and remove them from the micropores, thereby improving the degreasing performance.

[0058] 4) The performance comparison analysis of the high-efficiency and environmentally friendly acidic degreasers prepared in combination with Example 3 and Comparative Examples 7-8 shows that the emulsifying stabilizer is composed of neopentyl glycol dibenzoate and triethanolamine oleic acid soap in a mass ratio of 3:5. The synergistic effect between neopentyl glycol dibenzoate and triethanolamine oleic acid soap is mainly reflected in the following aspects: Complementarity: neopentyl glycol dibenzoate mainly plays the role of emulsification, dispersion and wetting, while triethanolamine oleic acid soap mainly plays the role of emulsification, washing and antistatic. The combination of the two can give full play to their respective advantages and improve the comprehensive performance of the degreaser. Stability: neopentyl glycol dibenzoate can maintain the chemical balance between the components, prevent light, thermal decomposition or oxidative decomposition, while triethanolamine oleic acid soap can be adsorbed at the interface of oil and water, reducing the corrosion ability of inorganic acid to surface metal. The combination of the two can improve the stability of the degreaser at high and low temperatures, so that the potion can maintain an excellent degreasing effect for a long time.

[0059] 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 highly efficient and environmentally friendly acidic degreasing agent, characterized in that: The preparation raw materials include the following by weight: 30-40 parts of inorganic acid, 12-15 parts of corrosion inhibitor, 40-50 parts of wetting agent, 10-12 parts of emulsion stabilizer, 8-10 parts of isoeugenol, 15-18 parts of plant degreasing liquid and 850-870 parts of deionized water.

2. A highly efficient and environmentally friendly acidic degreasing agent according to claim 1, characterized in that: The inorganic acid is composed of sulfuric acid with a mass concentration of 98% and hydrochloric acid with a mass concentration of 37% in a mass ratio of 4:1-2.

3. A highly efficient and environmentally friendly acidic degreasing agent according to claim 1, characterized in that: The corrosion inhibitor consists of β-cyclocitral, terephthalaldehyde and mercaptobenzothiazole in a mass ratio of 5:3:

2.

4. The highly efficient and environmentally friendly acidic degreasing agent according to claim 1, characterized in that: The wetting agent is composed of lauryl polyoxyethylene ether, dodecyl ethoxy sulfobetaine and asparagine-choline ionic liquid in a mass ratio of 4:7:

3.

5. A highly efficient and environmentally friendly acidic degreasing agent according to claim 4, 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., a choline hydroxide aqueous solution with a mass concentration of 121 g / L is slowly added dropwise to an aqueous solution of D-asparagine with a mass concentration of 66 g / L; after the addition is completed, the solution is neutralized and reacted for 36-48 hours under the stirring condition of room temperature; after the reaction, the solution is vacuum dried and dehydrated; acetonitrile is used as a solvent for redissolution; the acetonitrile is removed under reduced pressure; and finally, the solution is vacuum dried and placed in a desiccator for standby use, thereby obtaining the asparagine-choline ionic liquid.

6. A highly efficient and environmentally friendly acidic degreasing agent according to claim 5, characterized in that: The mass ratio of the choline hydroxide aqueous solution with a mass concentration of 121 g / L to the D-asparagine aqueous solution with a mass concentration of 66 g / L is 1:

2.

7. The highly efficient and environmentally friendly acidic degreasing agent according to claim 1, characterized in that: The emulsion stabilizer is composed of neopentyl glycol dibenzoate and triethanolamine oleic acid soap in a mass ratio of 3:

5.

8. The highly efficient and environmentally friendly acidic degreasing agent according to claim 1, characterized in that: The method for preparing the plant degreasing liquid comprises the following steps: S81. According to the mass fraction, the washed and dried orange peel and lemon peel are crushed to obtain crushed blocks after crushing to 50 mesh; S82. Add the crushed pieces into a citric acid solution with a mass concentration of 50% according to the mass fraction and boil them. After boiling for 30-40 minutes, filter out the impurities to obtain a plant deoiling liquid.

9. A highly efficient and environmentally friendly acidic degreasing agent according to claim 8, characterized in that: The mass ratio of the orange peel, lemon peel and citric acid solution with a mass concentration of 50% is 1:1:

4.

10. A method for preparing a highly efficient and environmentally friendly acidic degreasing agent according to any one of claims 1 to 9, characterized in that: The following steps are involved: S101, adding inorganic acid, corrosion inhibitor, plant degreasing liquid and isoeugenol in parts by mass to deionized water, mixing well, and heating to a temperature of 50-60° C. to obtain a mixed solution A; S102, adding a wetting agent and an emulsion stabilizer into the mixed solution A, stirring the reaction for 2-3 hours at a stirring rate of 150-180 r / min, to obtain a highly efficient and environmentally friendly acidic degreasing agent.

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