Efficient soldering flux and preparation method thereof

Abstract

The invention belongs to the technical field of welding materials, and particularly relates to efficient scaling powder and a preparation method thereof. The efficient scaling powder is composed of, by mass, 4%-10% of organic acid activating agents, 1%-2% of thiourea reinforcing agents, 0.15%-0.3% of wetting agents, 0.2%-0.6% of antioxidants, 0.3%-0.5% of surfactants, 0.05%-0.2% of defoaming agents, 3%-5% of film forming agents, 10%-15% of solvents and the balance water. The prepared scaling powder has good spreadability, stability, corrosion resistance and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of welding materials, and particularly relates to a high-efficiency soldering flux and a preparation method thereof. Background Art

[0002] In the lead-free process, lead-free solders are constantly being proposed. However, since lead-free solders often do not wet substrates directly, soldering requires the assistance of flux. Flux is a chemical substance that promotes or accelerates the wetting of metals by molten solder during the soldering process and also provides protection. It primarily includes solvents, activators, film-forming agents, surfactants, and other components. During the soldering process, flux primarily removes oxides and impurities from the metal surfaces of the solder and substrate, preventing further oxidation of the solder.

[0003] Traditional fluxes often use organic halide activators to improve the solderability of the soldering process, but organic halide activators are usually highly corrosive and can cause certain harm to the human body or the environment; therefore, low-halogen or halogen-free fluxes have become a research hotspot.

[0004] The Chinese patent application document with application publication number CN102248317A discloses a halogen-free and lead-free solder wire. The components of the flux include 0.1-0.2 parts of rosin, 0.1-0.2 parts of non-fluorine and chlorine-free environmentally friendly organic solvents, 0.05-0.06 parts of thixotropic agents, 0.02-0.4 parts of organic active agents, 0.01-0.02 parts of corrosion inhibitors, and 0.01-0.02 parts of surfactants. The active agent system in this technical solution mainly uses glutaric acid and ethylenediamine. Only a small amount of organic acid is used as an active agent in the flux. The flux activity is obviously insufficient, and it is difficult to fully remove the oxides on the solder surface in a short time. This may cause poor wetting and spreading of the solder on the solder surface, affecting the welding quality and causing problems such as cold soldering and false soldering.

[0005] In summary, there is a need for a flux that is halogen-free, has strong soldering performance and has good comprehensive properties. Summary of the Invention

[0006] Existing soldering fluxes have the problem of being difficult to achieve both halogen-free and high soldering performance. In order to solve this problem, the present invention provides a high-efficiency soldering flux and a preparation method thereof.

[0007] In order to achieve the purpose of the present invention, the present invention adopts the following technical solutions: In a first aspect, the present invention provides a high-efficiency soldering flux, comprising the following components in percentage by mass: Organic acid activator 4%-10%, thiourea enhancer 1%-2%, wetting agent 0.15%-0.3%, antioxidant 0.2%-0.6%, surfactant 0.3%-0.5%, defoaming agent 0.05%-0.2%, film former 3%-5%, solvent 10%-15%, the balance is water; By adopting the above technical solution, the content of organic acid activator is 4%-10%, which can effectively remove oxides on the welding surface. The 1%-2% thiourea enhancer can enhance the activity of the organic acid activator, further reducing defects such as cold solder joints and leaking solder joints. When compounded with wetting agents, surfactants, antioxidants and other components, the flux has good spreadability, antioxidant properties and other properties.

[0008] The organic acid activator is prepared by mixing an acrylic acid activator, malic acid and salicylic acid in a mass ratio of (3-4): (1.5-2.5):1.

[0009] By adopting the above technical solution, the proportions of the three components are relatively balanced and the overall performance is good. The acrylic activator provides strong activity, and the malic acid plays an auxiliary activation role. At the same time, it has a certain mildness and can reduce corrosion to the weldment. The appropriate addition of salicylic acid can improve the wettability and spreadability of the flux, so that the flux can spread better on the surface of the weldment, prevent re-oxidation, and improve the welding quality.

[0010] Preferably, the preparation method of the acrylic activator comprises the following steps: (1) 2-Ethylimidazole, vinylbenzyl chloride, potassium carbonate and N,N-dimethylformamide were mixed evenly, heated to react, filtered, rotary evaporated, extracted, washed, dried, and passed through a chromatographic column to obtain compound A; (2) Compound A, methacrylic acid, initiator and tetrahydrofuran are mixed evenly, heated to react, rotary evaporated, separated, washed and dried to obtain an acrylic activator.

[0011] By adopting this technical solution, the imidazole ring introduced into the acrylic activator possesses strong basicity and coordination capacity, reacting with oxides on the metal surface and effectively removing the oxide layer. Furthermore, after polymerization with methacrylic acid, the active groups on the polymer chain are evenly distributed, allowing for rapid and sufficient reaction with oxides on the weld surface during welding, improving activation efficiency.

[0012] The reaction formula of compound A is as follows:

[0013] The reaction formula of the acrylic activator is as follows:

[0014] Preferably, in step (1), the molar ratio of 2-ethylimidazole, vinylbenzyl chloride and potassium carbonate is (1.2-1.45):1:(1.5-1.9); the reaction temperature is 80-95°C, and the reaction time is 7-10 hours.

[0015] By adopting the above technical solution, under this ratio, vinylbenzyl chloride can participate in the reaction as completely as possible, reducing the residual unreacted vinylbenzyl chloride and improving the conversion rate of the reaction; within this temperature and time range, the reaction of 2-ethylimidazole and vinylbenzyl chloride can proceed smoothly and the occurrence of side reactions can be avoided.

[0016] Preferably, in step (2), the molar ratio of compound A to methacrylic acid is (1.1-1.5):1; the amount of initiator used is 0.5%-1% of the total mass of compound A and methacrylic acid; the reaction temperature is 75-85°C, and the reaction time is 8-12 hours.

[0017] By adopting the above technical solution, when the molar ratio of compound A to methacrylic acid is (1.1-1.5):1, the number of imidazole and acrylic acid groups on the acrylic activator is well balanced. The imidazole groups have strong coordination ability and reactivity towards metal oxides, while the acrylic acid groups provide certain acidity and polarity. This balance between the two can effectively exert the activation and wetting properties of the flux. Too low an initiator dosage can easily lead to insufficient free radical generation, slow reaction rate, and long reaction time. Too high an initiator dosage can lead to excessively fast reaction rate, making the reaction difficult to control and increasing the number of byproducts.

[0018] Preferably, the thiourea enhancer is selected from one or more of thiourea, methylthiourea and dimethylthiourea.

[0019] By adopting the above technical solution, active groups such as amino and thiol groups in the thiourea compound can react with metal oxides, further improving the removal effect of the oxide layer on the surface of the weldment, and can effectively enhance the reducing ability of the acrylic activator, which is beneficial to welding; at the same time, during the welding process, the thiourea compound can be adsorbed on the surface of the weldment and cooperate with the acrylic activator to enhance the adhesion and corrosion resistance of the film, prevent the weldment from being oxidized again during the welding process, and ensure the welding quality.

[0020] Preferably, the wetting agent is selected from one or more of ethylene glycol butyl ether acetate, diethyl succinate or dihexyl adipate.

[0021] By adopting the above technical solution, substances such as ethylene glycol butyl ether acetate can effectively reduce the surface tension of the liquid, have a good wetting effect on the surface of the weldment, and enable the flux to spread quickly on the metal surface during the welding process, thereby improving the uniformity and reliability of the welding.

[0022] Preferably, the antioxidant is prepared by mixing tert-butylhydroquinone, tea polyphenols and ferulic acid in a mass ratio of 1:(2-3):1.

[0023] By adopting the above technical solution, tert-butylhydroquinone can effectively inhibit the oxidation of oils and fats, tea polyphenols contain multiple phenolic hydroxyl groups, which can provide hydrogen atoms to neutralize free radicals, and the benzene ring structure of ferulic acid can stabilize free radicals through the conjugation effect. The three work synergistically to ensure the antioxidant effect while reducing the use of synthetic antioxidants.

[0024] Preferably, the film-forming agent is one or more of polyethylene glycol 1000, polyethylene glycol 2000, polyethylene glycol 4000 and polyethylene glycol 6000.

[0025] By adopting the above technical solution, using polyethylene glycol series compounds as film-forming agents can effectively protect the welding parts from corrosion by the external environment after welding; at the same time, the polyethylene glycol series compounds can be evenly mixed with components such as acrylic activators in the flux system, and the long-chain molecular structure of polyethylene glycol can be interspersed between the acrylic activator molecules to form a stable dispersion system without stratification, flocculation and other phenomena, thereby ensuring that the flux maintains uniformity during storage and use.

[0026] Preferably, the solvent is prepared by mixing ethylene glycol and isopropyl alcohol in a mass ratio of (2-3):1.

[0027] By adopting the above technical solution, the compounding of ethylene glycol and isopropyl alcohol can make various ingredients in the flux, such as organic acid activators and polyethylene glycol, uniformly dispersed and fully dissolved, forming a stable and uniform flux system, avoiding precipitation and stratification of ingredients caused by poor dissolution, which affects the performance of the flux; under this ratio, the volatilization rate of the two is moderate, and the spreadability of the flux is better.

[0028] In a second aspect, the present invention provides a method for preparing the above-mentioned high-efficiency soldering flux, comprising the following steps: S1: Mix the film-forming agent, solvent and water at 65-80°C to obtain mixture A; S2: Mixing the wetting agent, antioxidant, surfactant and mixture A at 65-80°C to obtain mixture B; S3: Evenly mix the organic acid activator, thiourea enhancer, defoamer and mixture B, adjust the pH to 6-7, and evenly mix at a temperature of 65-80°C to obtain a high-efficiency soldering flux.

[0029] By adopting the above technical solution and adjusting the component mixing sequence, temperature control, pH adjustment and other links in the preparation method, the prepared flux has good composition uniformity and chemical stability.

[0030] In summary, the beneficial effects of the present invention are: (1) The present invention compounds an organic acid activator with a thiourea enhancer to reduce the surface tension of the solder and enhance the activation performance; adding components such as a wetting agent, a surfactant, and a defoaming agent can improve the spreadability and permeability of the flux on the surface of the weldment, ensure the stability of the system, and optimize the welding effect; the various components cooperate with each other to make the flux have good spreadability, stability, corrosion resistance and other properties; (2) The present invention prepares an acrylic activator with an imidazole ring, which has strong alkalinity and coordination ability and can effectively remove the oxide layer; the nitrogen atom in the imidazole ring contains a lone pair of electrons and can form a coordination bond with the metal surface, which helps the activator to be evenly distributed on the metal surface and improves the spreadability and other properties of the flux; (3) The present invention further compounds acrylic acid activator, malic acid and salicylic acid to make the flux more active and spread better, thereby improving the welding quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is the infrared spectrum of the acrylic activator of the present invention. DETAILED DESCRIPTION

[0032] The technical solution of the present invention is explained in detail below with reference to several representative embodiments of the present invention.

[0033] Unless otherwise specified, the experimental methods used in the following examples and comparative examples are all conventional methods. Unless otherwise specified, the materials, reagents, etc. used in the following examples and comparative examples are all commercially available.

[0034] Example 1 A high-efficiency soldering flux of this embodiment is composed of the following components: Acrylic activator 4g, malic acid 3g, salicylic acid 1g, methylthiourea 2g, dihexyl adipate 0.2g, tert-butylhydroquinone 0.1g, tea polyphenols 0.2g, ferulic acid 0.1g, Tween 80 0.3g, polydimethylsiloxane 0.2g, polyethylene glycol 6000 3g, ethylene glycol 9g, isopropyl alcohol 3g, water 73.9g; The preparation method of a high-efficiency soldering flux of this embodiment comprises the following specific steps: S1: Stir 3 g of polyethylene glycol 6000, 9 g of ethylene glycol, 3 g of isopropyl alcohol, and 73.9 g of water at 80°C for 1 h to obtain mixture A; S2: Add 0.2 g of dihexyl adipate, 0.1 g of tert-butylhydroquinone, 0.2 g of tea polyphenols, 0.1 g of ferulic acid, and 0.3 g of Tween 80 to the mixture A prepared in step S1, and stir at 80° C. for 1 h to obtain a mixture B; S3: Add 4 g of acrylic activator, 3 g of malic acid, 1 g of salicylic acid, 2 g of methylthiourea, and 0.2 g of polydimethylsiloxane to the mixture B prepared in step S2, adjust the pH to 7, and stir at 80°C for 3 h to obtain a high-efficiency flux.

[0035] The preparation method of the acrylic acid activator of this embodiment comprises the following specific steps: (1) Add 6.25 g of 2-ethylimidazole, 7.6 g of vinylbenzyl chloride, 10.37 g of potassium carbonate and 100 mL of N,N-dimethylformamide to a three-necked flask, heat to 80°C and react for 10 h, filter, remove N,N-dimethylformamide by rotary evaporation, extract with dichloromethane, wash with hydrochloric acid and deionized water, dry with anhydrous magnesium sulfate, and pass through a chromatographic column to obtain compound A; (2) Add 2.76 g of compound A, 8.6 g of methacrylic acid, 0.09 g of benzoyl peroxide and 65 mL of tetrahydrofuran into a three-necked flask and stir for 30 min. Heat to 80 °C and react for 10 h. Remove tetrahydrofuran by rotary evaporation. Add n-hexane to precipitate, filter, wash with deionized water, and dry in a vacuum drying oven at 60 °C for 10 h to obtain an acrylic activator.

[0036] Figure 1 This is the infrared spectrum of acrylic activator. Figure 1 It can be seen that 2998cm -1 The stretching vibration peak of -OH is at 2938cm -1 、2869cm -1 The stretching vibration absorption peak of -CH is at 1752cm -1 The stretching vibration peak of C=O is at 1637cm -1 The peak at 1590 cm is the stretching vibration peak of the benzene ring skeleton; -1 1520cm -1 The stretching vibration peak of C=N is at 1494cm -1 、1455cm -1 The peak at 1391 cm is the bending vibration peak of benzene ring hydrogen; -1 The stretching vibration peak of CN is at 839cm -1 and 761cm -1 The places are the out-of-plane bending vibration peaks of CH on the benzene ring.

[0037] Example 2 A high-efficiency soldering flux of this embodiment is composed of the following components: Acrylic activator 3.5g, malic acid 1.5g, salicylic acid 1g, thiourea 2g, diethyl succinate 0.15g, tert-butylhydroquinone 0.14g, tea polyphenols 0.32g, ferulic acid 0.14g, Tween 80 0.4g, polydimethylsiloxane 0.05g, polyethylene glycol 4000 5g, ethylene glycol 10g, isopropyl alcohol 5g, water 73.8g; The preparation method of a high-efficiency soldering flux of this embodiment comprises the following specific steps: S1: Stir 5 g of polyethylene glycol 4000, 10 g of ethylene glycol, 5 g of isopropyl alcohol, and 73.8 g of water at 65°C for 1 h to obtain mixture A; S2: 0.15 g of diethyl succinate, 0.14 g of tert-butylhydroquinone, 0.32 g of tea polyphenols, 0.14 g of ferulic acid, and 0.4 g of Tween 80 were added to the mixture A prepared in step S1, and the mixture was stirred at 65° C. for 1 h to obtain a mixture B; S3: Add 3.5 g of acrylic activator, 1.5 g of malic acid, 1 g of salicylic acid, 2 g of thiourea, and 0.05 g of polydimethylsiloxane to the mixture B prepared in step S2, adjust the pH to 7, and stir at 65° C. for 3 h to obtain a high-efficiency soldering flux.

[0038] The preparation method of the acrylic acid activator of this embodiment comprises the following specific steps: (1) Add 5.77 g of 2-ethylimidazole, 7.6 g of vinylbenzyl chloride, 12.44 g of potassium carbonate and 100 mL of N,N-dimethylformamide to a three-necked flask, heat to 95°C and react for 7 h, filter, remove N,N-dimethylformamide by rotary evaporation, extract with dichloromethane, wash with hydrochloric acid and deionized water, dry with anhydrous magnesium sulfate, and pass through a chromatographic column to obtain compound A; (2) Add 2.55 g of compound A, 8.6 g of methacrylic acid, 1.11 g of benzoyl peroxide and 65 mL of tetrahydrofuran into a three-necked flask and stir for 30 min. Heat to 75 °C and react for 12 h. Remove tetrahydrofuran by rotary evaporation. Add n-hexane to precipitate, filter, wash with deionized water, and dry in a vacuum drying oven at 60 °C for 10 h to obtain an acrylic activator.

[0039] Example 3 A high-efficiency soldering flux of this embodiment is composed of the following components: Acrylic activator 3g, malic acid 2g, salicylic acid 1g, methylthiourea 2g, ethylene glycol butyl ether acetate 0.3g, tert-butylhydroquinone 0.05g, tea polyphenols 0.1g, ferulic acid 0.05g, Tween 80 0.4g, polydimethylsiloxane 0.1g, polyethylene glycol 2000 4g, ethylene glycol 8.7g, isopropyl alcohol 4.3g, water 74.5g; The preparation method of a high-efficiency soldering flux of this embodiment comprises the following specific steps: S1: Stir 4 g of polyethylene glycol 2000, 8.7 g of ethylene glycol, 4.3 g of isopropyl alcohol, and 74.5 g of water at 70°C for 1 h to obtain mixture A; S2: Add 0.3 g of ethylene glycol butyl ether acetate, 0.05 g of tert-butylhydroquinone, 0.1 g of tea polyphenols, 0.05 g of ferulic acid, and 0.4 g of Tween 80 to the mixture A prepared in step S1, and stir at 70° C. for 1 h to obtain a mixture B; S3: Add 3 g of acrylic activator, 2 g of malic acid, 1 g of salicylic acid, 2 g of methylthiourea, and 0.1 g of polydimethylsiloxane to the mixture B prepared in step S2, adjust the pH to 6, and stir at 70°C for 3 h to obtain a high-efficiency flux.

[0040] The preparation method of the acrylic acid activator of this embodiment comprises the following specific steps: (1) Add 6.92 g of 2-ethylimidazole, 7.6 g of vinylbenzyl chloride, 11.759 g of potassium carbonate and 100 mL of N,N-dimethylformamide to a three-necked flask, heat to 90°C and react for 8 h, filter, remove N,N-dimethylformamide by rotary evaporation, extract with dichloromethane, wash with hydrochloric acid and deionized water, dry with anhydrous magnesium sulfate, and pass through a chromatographic column to obtain compound A; (2) Add 2.34 g of compound A, 8.6 g of methacrylic acid, 0.06 g of benzoyl peroxide and 65 mL of tetrahydrofuran into a three-necked flask and stir for 30 min. Heat to 85 °C and react for 8 h. Remove tetrahydrofuran by rotary evaporation. Add n-hexane to precipitate, filter, wash with deionized water, and dry in a vacuum drying oven at 60 °C for 10 h to obtain an acrylic activator.

[0041] Example 4 A high-efficiency soldering flux of this embodiment is composed of the following components: Acrylic activator 5.1g, malic acid 3.5g, salicylic acid 1.4g, dimethylthiourea 2g, ethylene glycol butyl ether acetate 0.2g, tert-butylhydroquinone 0.1g, tea polyphenols 0.3g, ferulic acid 0.1g, Tween 80 0.5g, polydimethylsiloxane 0.05g, polyethylene glycol 1000 4g, ethylene glycol 7.2g, isopropyl alcohol 2.8g, water 72.75g; The preparation method of a high-efficiency soldering flux of this embodiment comprises the following specific steps: S1: Stir 4 g of polyethylene glycol 1000, 7.2 g of ethylene glycol, 2.8 g of isopropyl alcohol, and 72.75 g of water at 75°C for 1 h to obtain mixture A; S2: Add 0.2 g of ethylene glycol butyl ether acetate, 0.1 g of tert-butylhydroquinone, 0.3 g of tea polyphenols, 0.1 g of ferulic acid, and 0.5 g of Tween 80 to the mixture A prepared in step S1, and stir at 75° C. for 1 h to obtain a mixture B; S3: Add 5.1 g of acrylic activator, 3.5 g of malic acid, 1.4 g of salicylic acid, 2 g of dimethylthiourea, and 0.05 g of polydimethylsiloxane to the mixture B prepared in step S2, adjust the pH to 6, and stir at 75°C for 3 h to obtain a high-efficiency soldering flux.

[0042] The preparation method of the acrylic acid activator of this embodiment comprises the following specific steps: (1) Add 6.73 g of 2-ethylimidazole, 7.6 g of vinylbenzyl chloride, 11.75 g of potassium carbonate and 100 mL of N,N-dimethylformamide to a three-necked flask, heat to 92 °C and react for 9 h, filter, remove N,N-dimethylformamide by rotary evaporation, extract with dichloromethane, wash with hydrochloric acid and deionized water, dry with anhydrous magnesium sulfate, and pass through a chromatographic column to obtain compound A; (2) Add 3.18 g of compound A, 8.6 g of methacrylic acid, 0.08 g of benzoyl peroxide and 65 mL of tetrahydrofuran into a three-necked flask and stir for 30 min. Heat to 75 °C and react for 10 h. Remove tetrahydrofuran by rotary evaporation. Add n-hexane to precipitate, filter, wash with deionized water, and dry in a vacuum drying oven at 60 °C for 10 h to obtain an acrylic activator.

[0043] Comparative Example 1 The difference from Example 1 is that in the preparation method of the acrylic activator of this comparative example, styrene is used instead of an equal amount of compound A to react with methacrylic acid, and the rest is the same as Example 1.

[0044] Comparative Example 2 The difference from Example 1 is that the mass ratio of the acrylic activator, malic acid and salicylic acid in this comparative example is 2:5:3, and the rest is the same as Example 1.

[0045] Comparative Example 3 The difference from Example 1 is that the mass ratio of tert-butylhydroquinone, tea polyphenols and ferulic acid in this comparative example is 3:1:1, and the rest is the same as Example 1.

[0046] Comparative Example 4 The difference from Example 1 is that the solvent in this comparative example is ethylene glycol, and the rest is the same as Example 1.

[0047] Comparative Example 5 The difference from Example 1 is that the high-efficiency soldering flux of this comparative example is composed of the following components: Acrylic activator 1g, malic acid 0.5g, salicylic acid 1g, dihexyl adipate 0.2g, tert-butylhydroquinone 0.1g, ferulic acid 0.1g, Tween 80 0.6g, polydimethylsiloxane 0.2g, polyethylene glycol 6000 3g, ethylene glycol 9g, isopropyl alcohol 3g, water 81.3g.

[0048] Related performance tests According to the relevant test methods specified in the international standard IPC-TM-650, the above-mentioned Examples 1 to 4 and Comparative Examples 1 to 5 were respectively tested for related performance such as expansion rate, copper plate corrosion, and surface insulation resistance. The test results are shown in Table 1.

[0049] Table 1 Test results

[0050] From the comparison between Comparative Example 1 and Example 1, it can be seen that the introduction of imidazole ring into the acrylic activator can improve the surface insulation resistance, corrosion resistance and other properties of the flux.

[0051] From the comparison between Comparative Example 2 and Example 1, it can be seen that reducing the proportion of the acrylic activator may reduce the continuity of the film formed on the surface of the weldment, but due to the good wettability of malic acid, this deficiency can be compensated to a certain extent, so the effect on the expansion rate is not significant; however, malic acid contains more hydroxyl and carboxyl groups and has a certain polarity. Increasing its usage will increase the polar groups, reduce the surface insulation performance, and aggravate the corrosion of the copper plate.

[0052] From the comparison between Comparative Example 3 and Example 1, it can be seen that the performance of the flux is basically not affected. Therefore, the use of tea polyphenols and ferulic acid instead can reduce the use amount of the synthetic antioxidant tert-butylhydroquinone.

[0053] From the comparison between Comparative Example 4 and Example 1, it can be seen that using ethylene glycol as the only solvent will reduce the spreadability of the flux.

[0054] By comparing Comparative Example 5 with Example 1, it can be seen that the components and dosage ratio of the high-efficiency flux are adjusted in this comparative example, and the spreadability, corrosion resistance and other properties of the flux are reduced, which proves that the components and dosage ratio of the high-efficiency flux of the present invention have been optimized. Changing the dosage ratio and replacing the components will make the effect of the obtained flux worse.

[0055] The above is an exemplary description of the present invention. It should be noted that, without departing from the core of the present invention, any simple deformation, modification or other equivalent replacement that can be made by other skilled in the art without expending creative labor shall fall within the scope of protection of the present invention.

Claims

1. A high-efficiency soldering flux, characterized in that: It is composed of the following components in percentage by mass: Organic acid activator 4%-10%, thiourea enhancer 1%-2%, wetting agent 0.15%-0.3%, antioxidant 0.2%-0.6%, surfactant 0.3%-0.5%, defoaming agent 0.05%-0.2%, film former 3%-5%, solvent 10%-15%, the balance is water; The organic acid activator is prepared by mixing an acrylic acid activator, malic acid and salicylic acid in a mass ratio of (3-4): (1.5-2.5):

1.

2. A high-efficiency soldering flux according to claim 1, characterized in that: The preparation method of the acrylic activator comprises the following steps: (1) 2-Ethylimidazole, vinylbenzyl chloride, potassium carbonate and N,N-dimethylformamide were mixed evenly, heated to react, filtered, rotary evaporated, extracted, washed, dried, and passed through a chromatographic column to obtain compound A; (2) Compound A, methacrylic acid, initiator and tetrahydrofuran are mixed evenly, heated to react, rotary evaporated, separated, washed and dried to obtain an acrylic activator.

3. A high-efficiency soldering flux according to claim 2, characterized in that, In the step (1), the molar ratio of 2-ethylimidazole, vinylbenzyl chloride and potassium carbonate is (1.2-1.45):1:(1.5-1.9); the reaction temperature is 80-95°C, and the reaction time is 7-10 hours.

4. A high-efficiency soldering flux according to claim 2, characterized in that: In step (2), the molar ratio of compound A to methacrylic acid is (1.1-1.5):1; the amount of initiator used is 0.5%-1% of the total mass of compound A and methacrylic acid; the reaction temperature is 75-85°C, and the reaction time is 8-12 hours.

5. A high-efficiency soldering flux according to claim 1, characterized in that: The thiourea enhancer is selected from one or more of thiourea, methylthiourea and dimethylthiourea.

6. A high-efficiency soldering flux according to claim 1, characterized in that: The wetting agent is selected from one or more of ethylene glycol butyl ether acetate, diethyl succinate or dihexyl adipate.

7. A high-efficiency soldering flux according to claim 1, characterized in that: The antioxidant is prepared by mixing tert-butylhydroquinone, tea polyphenols and ferulic acid in a mass ratio of 1:(2-3):

1.

8. A high-efficiency soldering flux according to claim 1, characterized in that: The film-forming agent is one or more of polyethylene glycol 1000, polyethylene glycol 2000, polyethylene glycol 4000 and polyethylene glycol 6000.

9. The high-efficiency soldering flux according to claim 1, characterized in that: The solvent is prepared by mixing ethylene glycol and isopropyl alcohol in a mass ratio of (2-3):

1.

10. The method for preparing a high-efficiency soldering flux according to any one of claims 1 to 9, wherein: The steps include: S1: Mix the film-forming agent, solvent and water at 65-80°C to obtain mixture A; S2: Mixing the wetting agent, antioxidant, surfactant and mixture A at 65-80°C to obtain mixture B; S3: Evenly mix the organic acid activator, thiourea enhancer, defoamer and mixture B, adjust the pH to 6-7, and evenly mix at a temperature of 65-80°C to obtain a high-efficiency soldering flux.

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