High-efficiency flux and preparation method thereof

Abstract

The application belongs to the technical field of welding materials, and particularly relates to a high-efficiency flux and a preparation method thereof; the high-efficiency flux is composed of the following components in mass percentage: 4%-10% of organic acid activator, 1%-2% of thiourea enhancer, 0.15%-0.3% of wetting agent, 0.2%-0.6% of antioxidant, 0.3%-0.5% of surfactant, 0.05%-0.2% of defoaming agent, 3%-5% of film forming agent, 10%-15% of solvent, and the balance of water; the flux prepared by the application has good spreading property, stability, corrosion resistance and other performances.

Description

TECHNICAL FIELD

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

[0002] In the process of lead-free, lead-free solder is constantly proposed, since the lead-free solder often cannot be well directly wetted on the substrate, therefore, soldering needs to be performed with the aid of flux. The flux is a chemical substance capable of promoting or accelerating the wetting of metal by molten solder in the soldering process, and has a protective effect, mainly including solvents, active agents, film formers, surfactants and various components, and the flux mainly plays the roles of removing the oxides and impurities on the surface of the solder and the substrate metal, and preventing the solder from being oxidized again in the soldering process.

[0003] The traditional flux often uses organic halide activators to improve the solderability in the soldering process, but the organic halide activators usually have strong corrosiveness, and can cause certain harm to the human body or the environment; therefore, low-halogen or halogen-free fluxes are research hotspots.

[0004] A Chinese patent application file with the application publication number CN102248317A discloses a halogen-free lead-free soldering wire, and components of the flux include rosin 0.1-0.2 parts, non-fluorine and chlorine type environment-friendly organic solvent 0.1-0.2 parts, thixotropic agent 0.05-0.06 parts, organic active agent 0.02-0.4 parts, corrosion inhibitor 0.01-0.02 parts, and surfactant 0.01-0.02 parts; the active agent system in the technical solution mainly adopts glutaric acid and ethylenediamine, and only a small amount of organic acid is used as the active agent in the flux, the activity of the flux is obviously insufficient, the oxides on the surface of the solder are difficult to be fully removed in a short time, the wetting and spreading effect of the solder on the surface of the solder may be poor, the welding quality is affected, and problems such as virtual welding and false welding occur.

[0005] In summary, there is a need for a halogen-free flux with strong fluxing performance and good comprehensive performance. SUMMARY

[0006] The existing flux has the problem that halogen-free and strong fluxing performance are difficult to be achieved simultaneously; in order to solve the problem, the application provides a high-efficiency flux and a preparation method thereof.

[0007] In order to achieve the purpose of the application, the following technical solutions are adopted in the application:

[0008] In a first aspect, the application provides a high-efficiency flux, which is composed of the following components in mass percentage:

[0009] 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%, defoamer 0.05%-0.2%, film forming agent 3%-5%, solvent 10%-15%, and the rest is water;

[0010] By adopting the above technical scheme, the content of the organic acid activator is 4%-10%, which can effectively remove the oxides on the welding surface, the 1%-2% thiourea enhancer can enhance the activity of the organic acid activator, further reduce defects such as virtual welding and missed welding, and the composition of the wetting agent, the surfactant, the antioxidant and the like makes the flux have good spreading property, oxidation resistance and the like.

[0011] The organic acid activator is a mixture of acrylic activator, malic acid and salicylic acid in a mass ratio of (3-4) :(1.5-2.5) :1.

[0012] By adopting the above technical scheme, under the above ratio, the ratio of the three components is balanced, and the comprehensive performance is good; the acrylic activator provides strong activity, the malic acid plays a role in auxiliary activation, and at the same time has a certain mildness, which can reduce the corrosion to the welding parts, the appropriate addition of the salicylic acid can improve the wettability and spreading property of the flux, so that the flux can spread better on the surface of the welding parts, prevent re-oxidation, and improve the welding quality.

[0013] Preferably, the preparation method of the acrylic activator comprises the following steps:

[0014] (1) uniformly mix 2-ethyl imidazole, vinyl benzyl chloride, potassium carbonate and N,N-dimethyl formamide, heat and react, filter, rotary evaporate, extract, wash, dry, and pass through a chromatographic column to obtain compound A;

[0015] (2) uniformly mix compound A, methyl methacrylic acid, an initiator and tetrahydrofuran, heat and react, rotary evaporate, separate, wash, dry, and obtain the acrylic activator.

[0016] By adopting the above technical scheme, the imidazole ring introduced on the acrylic activator has strong basicity and coordination ability, can react with the oxides on the surface of the metal, and effectively removes the oxide layer. At the same time, after polymerization with methyl methacrylic acid, the active groups on the polymer chain are uniformly distributed, which can quickly and fully react with the oxides on the surface of the welding parts during the welding process, and improve the activation efficiency.

[0017] The reaction formula of the compound A is as follows:

[0018]

[0019] The reaction formula of the acrylic activator is as follows:

[0020]

[0021] Preferably, 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℃, and the reaction time is 7-10h.

[0022] By adopting the above technical solution, under the above ratio, the 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 the temperature and time range, the reaction of 2-ethylimidazole and vinylbenzyl chloride can proceed smoothly, and the occurrence of side reactions can be avoided.

[0023] Preferably, in the step (2), the molar ratio of compound A and methacrylic acid is (1.1-1.5) : 1; the amount of initiator is 0.5%-1% of the total mass of compound A and methacrylic acid; the reaction temperature is 75-85℃, and the reaction time is 8-12h.

[0024] By adopting the above technical solution, when the molar ratio of compound A and methacrylic acid is (1.1-1.5) : 1, the number of imidazole groups and acrylic acid groups on the acrylic activator can achieve a good balance, the imidazole group has strong coordination ability and reactivity to metal oxides, and the acrylic acid group provides certain acidity and polarity, and the balance of the number of the two can make the activation performance and wetting performance of the flux be better. Too low amount of initiator can easily lead to insufficient number of free radicals, slow reaction rate and long reaction time; too high amount of initiator can lead to fast reaction rate, which can make the reaction difficult to control and increase the by-products.

[0025] Preferably, the thiourea-based enhancer is selected from one or more of thiourea, methylthiourea and dimethylthiourea.

[0026] By adopting the above technical solution, the active groups such as amino and mercapto in the thiourea compound can react with metal oxides, further improving the removal effect of the surface oxide layer of the welding part, effectively enhancing the reducing capacity of the acrylic activator, and being beneficial to welding; at the same time, in the welding process, the thiourea compound can be adsorbed on the surface of the welding part, cooperating with the acrylic activator to enhance the adhesion and corrosion resistance of the film, prevent the welding part from being oxidized again during welding, and ensure the welding quality.

[0027] Preferably, the wetting agent is selected from one or more of ethylene glycol butyl ether acetate, diethyl succinate or dihexyl adipate.

[0028] By adopting the technical scheme, substances such as ethylene glycol butyl ether acetate can effectively reduce the liquid surface tension, have a good wetting effect on the surface of the welding part, make the flux rapidly spread on the metal surface in the welding process, and improve the uniformity and reliability of welding.

[0029] Preferably, the antioxidant is a mixture of tert-butyl hydroquinone, tea polyphenol and ferulic acid in a mass ratio of 1:(2-3):1.

[0030] By adopting the technical scheme, the tert-butyl hydroquinone can effectively inhibit the oxidation of oil and fat, the tea polyphenol can provide hydrogen atoms to neutralize free radicals, and the benzene ring structure of the ferulic acid can stabilize free radicals through the conjugation effect, so that the three components synergistically work together to ensure the antioxidant effect while reducing the use amount of synthetic antioxidants.

[0031] Preferably, the film-forming agent is one or more of polyethylene glycol 1000, polyethylene glycol 2000, polyethylene glycol 4000 and polyethylene glycol 6000.

[0032] By adopting the technical scheme, the polyethylene glycol series compounds are used as the film-forming agent, which can effectively protect the welding part from the erosion of the external environment after welding; meanwhile, the polyethylene glycol series compounds and the components such as the acrylic activator in the flux system can be uniformly mixed, the long-chain molecular structure of the polyethylene glycol can be inserted between the acrylic activator molecules to form a stable dispersion system, and the stratification and flocculation phenomena can be avoided, so that the uniformity of the flux can be ensured during storage and use.

[0033] Preferably, the solvent is a mixture of ethylene glycol and isopropyl alcohol in a mass ratio of (2-3):1.

[0034] By adopting the technical scheme, the mixture of ethylene glycol and isopropyl alcohol can uniformly disperse and fully dissolve various components such as the organic acid activator and polyethylene glycol in the flux, so that a stable and uniform flux system is formed, the precipitation and stratification of the components caused by poor dissolution are avoided, and the performance of the flux is affected; in the above ratio, the evaporation rate is moderate, and the spreading property of the flux is better.

[0035] In a second aspect, the application provides a preparation method of the high-efficiency flux.

[0036] S1: uniformly mix the film-forming agent, the solvent and water at a temperature of 65-80 DEG C to obtain a mixture A;

[0037] S2: uniformly mix the wetting agent, the antioxidant, the surfactant and the mixture A at a temperature of 65-80 DEG C to obtain a mixture B;

[0038] S3: the organic acid activator, thiourea enhancer, defoaming agent are mixed with mixture B, the pH is adjusted to 6-7, and the mixture is uniformly mixed at a temperature of 65-80 DEG C to obtain a high-efficiency flux.

[0039] By adjusting the component mixing order, temperature control, pH adjustment and other links in the preparation method, the prepared flux has good component uniformity and chemical stability.

[0040] In summary, the beneficial effects of the present application are:

[0041] (1) The organic acid activator and thiourea enhancer are compounded in the present application to reduce the surface tension of the solder and strengthen the activation performance; the addition of wetting agent, surfactant, defoaming agent and other components can improve the spreading and penetration of the flux on the surface of the welding part, ensure the system stability, and optimize the welding effect; the mutual cooperation of the components makes the flux have good spreading, stability, corrosion resistance and other properties;

[0042] (2) The present application prepares an acrylic activator with an imidazole ring, which has strong basicity and coordination ability, and can effectively remove the oxide layer; the nitrogen atom in the imidazole ring contains a lone pair of electrons, which can form a coordination bond with the metal surface, helping the activator to be evenly distributed on the metal surface and improving the spreading and other properties of the flux;

[0043] (3) The present application further compounds the acrylic activator, malic acid and salicylic acid, so that the flux has stronger activity and better spreading, and improves the welding quality. BRIEF DESCRIPTION OF DRAWINGS

[0044] Figure 1 The infrared spectrum of the acrylic activator of the present application is shown in the figure. DETAILED DESCRIPTION

[0045] The technical solutions of the present application will be explained in detail below with reference to several representative embodiments of the present application.

[0046] The experimental methods used in the following examples and comparative examples are conventional methods unless otherwise specified. The materials, reagents and the like used in the following examples and comparative examples can be obtained from commercial channels unless otherwise specified.

[0047] Example 1

[0048] The high-efficiency flux of the present embodiment is composed of the following components by mass:

[0049] Acrylic activator 4g, malic acid 3g, salicylic acid 1g, methyl thiourea 2g, adipic acid dihexyl ester 0.2g, tert-butyl hydroquinone 0.1g, tea polyphenol 0.2g, ferulic acid 0.1g, Tween 80 0.3g, dimethicone 0.2g, polyethylene glycol 6000 3g, ethylene glycol 9g, isopropyl alcohol 3g, water 73.9g;

[0050] The preparation method of the high-efficiency flux of the embodiment is as follows:

[0051] S1: 3g of polyethylene glycol 6000, 9g of ethylene glycol, 3g of isopropyl alcohol, and 73.9g of water are stirred at 80℃ for 1h to obtain a mixture A;

[0052] S2: 0.2g of adipic acid dihexyl ester, 0.1g of tert-butyl hydroquinone, 0.2g of tea polyphenol, 0.1g of ferulic acid, and 0.3g of Tween 80 are added to the mixture A obtained in step S1, and stirred at 80℃ for 1h to obtain a mixture B;

[0053] S3: 4g of acrylic activator, 3g of malic acid, 1g of salicylic acid, 2g of methyl thiourea, and 0.2g of dimethicone are added to the mixture B obtained in step S2, and adjusted to pH 7, and stirred at 80℃ for 3h to obtain the high-efficiency flux.

[0054] The preparation method of the acrylic activator of the embodiment is as follows:

[0055] (1) 6.25g of 2-ethylimidazole, 7.6g of vinylbenzyl chloride, 10.37g of potassium carbonate, and 100mL of N,N-dimethylformamide are added to a three-necked flask, heated to 80℃ for 10h, filtered, and N,N-dimethylformamide is removed by rotary evaporation, extracted by dichloromethane, washed by hydrochloric acid and deionized water, dried by anhydrous magnesium sulfate, and passed through a chromatographic column to obtain compound A;

[0056] (2) 2.76g of compound A, 8.6g of methyl methacrylate, 0.09g of benzoyl peroxide, and 65mL of tetrahydrofuran are added to a three-necked flask, stirred for 30min, heated to 80℃ for 10h, and tetrahydrofuran is removed by rotary evaporation, precipitated by adding n-hexane, filtered, washed by deionized water, and dried in a vacuum drying box at 60℃ for 10h to obtain the acrylic activator.

[0057] Figure 1 The infrared spectrum of the acrylic activator is shown in the figure. Figure 1 It can be seen that 2998cm -1 is the stretching vibration peak of -OH; 2938cm -1 , 2869cm -1 are the stretching vibration absorption peaks of -CH; 1752cm -1stretching vibration peak of C=0; 1637 cm -1 stretching vibration peak of benzene ring skeleton; 1590 cm -1 and 1520 cm -1 stretching vibration peak of C=N; 1494 cm -1 , 1455 cm -1 bending vibration peak of benzene ring hydrogen; 1391 cm -1 stretching vibration peak of C-N; 839 cm -1 and 761 cm -1 out-of-plane bending vibration peak of C-H on benzene ring.

[0058] Example 2

[0059] The high-efficiency flux of this example is composed of the following components by mass:

[0060] 3.5 g of acrylic activator, 1.5 g of malic acid, 1 g of salicylic acid, 2 g of thiourea, 0.15 g of diethyl succinate, 0.14 g of tert-butyl hydroquinone, 0.32 g of tea polyphenol, 0.14 g of ferulic acid, 0.4 g of Tween 80, 0.05 g of polydimethylsiloxane, 5 g of polyethylene glycol 4000, 10 g of ethylene glycol, 5 g of isopropyl alcohol, and 73.8 g of water;

[0061] The preparation method of the high-efficiency flux of this example is as follows:

[0062] S1: 5 g of polyethylene glycol 4000, 10 g of ethylene glycol, 5 g of isopropyl alcohol, and 73.8 g of water were stirred at 65°C for 1 h to obtain a mixture A;

[0063] S2: 0.15 g of diethyl succinate, 0.14 g of tert-butyl hydroquinone, 0.32 g of tea polyphenol, 0.14 g of ferulic acid, and 0.4 g of Tween 80 were added to the mixture A prepared in step S1, and stirred at 65°C for 1 h to obtain a mixture B;

[0064] S3: 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 were added to the mixture B prepared in step S2, and the pH was adjusted to 7, and stirred at 65°C for 3 h to obtain the high-efficiency flux.

[0065] The preparation method of the acrylic activator of this example is as follows:

[0066] (1) 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 were added into a three-necked flask, and the mixture was reacted at 95°C for 7 h, filtered, and N,N-dimethylformamide was removed by rotary evaporation, extracted with dichloromethane, washed with hydrochloric acid and deionized water, dried over anhydrous magnesium sulfate, and then subjected to column chromatography to obtain compound A;

[0067] (2) 2.55 g of compound A, 8.6 g of methacrylic acid, 1.11 g of benzoyl peroxide and 65 mL of tetrahydrofuran were added into a three-necked flask, and the mixture was stirred for 30 min, and then reacted at 75°C for 12 h. Tetrahydrofuran was removed by rotary evaporation, and then precipitated by adding n-hexane, filtered, washed with deionized water, and dried in a vacuum drying oven at 60°C for 10 h to obtain an acrylic activator.

[0068] Example 3

[0069] The high-efficiency flux of the present example is composed of the following components by mass:

[0070] 3 g of acrylic activator, 2 g of malic acid, 1 g of salicylic acid, 2 g of methyl thiourea, 0.3 g of ethylene glycol butyl ether acetate, 0.05 g of tert-butyl hydroquinone, 0.1 g of tea polyphenol, 0.05 g of ferulic acid, 0.4 g of Tween 80, 0.1 g of polydimethylsiloxane, 4 g of polyethylene glycol 2000, 8.7 g of ethylene glycol, 4.3 g of isopropyl alcohol, and 74.5 g of water;

[0071] The preparation method of the high-efficiency flux of the present example is as follows:

[0072] S1: 4 g of polyethylene glycol 2000, 8.7 g of ethylene glycol, 4.3 g of isopropyl alcohol and 74.5 g of water were stirred at 70°C for 1 h to obtain a mixture A;

[0073] S2: 0.3 g of ethylene glycol butyl ether acetate, 0.05 g of tert-butyl hydroquinone, 0.1 g of tea polyphenol, 0.05 g of ferulic acid and 0.4 g of Tween 80 were added into the mixture A obtained in step S1, and the mixture was stirred at 70°C for 1 h to obtain a mixture B;

[0074] S3: 3 g of acrylic activator, 2 g of malic acid, 1 g of salicylic acid, 2 g of methyl thiourea, 0.1 g of polydimethylsiloxane were added into the mixture B obtained in step S2, and the pH was adjusted to 6, and then the mixture was stirred at 70°C for 3 h to obtain a high-efficiency flux.

[0075] The preparation method of the acrylic activator of the present example is as follows:

[0076] (1) 6.92 g of 2-ethyl imidazole, 7.6 g of vinyl benzyl chloride, 11.759 g of potassium carbonate and 100 mL of N,N-dimethyl formamide were added into a three-necked flask, and the mixture was reacted at 90°C for 8 h, filtered, and N,N-dimethyl formamide was removed by rotary evaporation, extracted by dichloromethane, washed by hydrochloric acid and deionized water, dried by anhydrous magnesium sulfate, and then subjected to column chromatography to obtain compound A;

[0077] (2) 2.34 g of compound A, 8.6 g of methacrylic acid, 0.06 g of benzoyl peroxide and 65 mL of tetrahydrofuran were added into a three-necked flask, stirred for 30 min, and then the mixture was reacted at 85°C for 8 h. Tetrahydrofuran was removed by rotary evaporation, precipitated by adding n-hexane, filtered, washed by deionized water, and dried in a vacuum drying oven at 60°C for 10 h to obtain an acrylic activator.

[0078] Example 4

[0079] The high-efficiency flux of the present example is composed of the following components:

[0080] 5.1 g of acrylic activator, 3.5 g of malic acid, 1.4 g of salicylic acid, 2 g of dimethyl thiourea, 0.2 g of ethylene glycol butyl ether acetate, 0.1 g of tert-butyl hydroquinone, 0.3 g of tea polyphenol, 0.1 g of ferulic acid, 0.5 g of Tween 80, 0.05 g of polydimethylsiloxane, 4 g of polyethylene glycol 1000, 7.2 g of ethylene glycol, 2.8 g of isopropyl alcohol and 72.75 g of water;

[0081] The preparation method of the high-efficiency flux of the present example is as follows:

[0082] S1: 4 g of polyethylene glycol 1000, 7.2 g of ethylene glycol, 2.8 g of isopropyl alcohol and 72.75 g of water were stirred at 75°C for 1 h to obtain mixture A;

[0083] S2: 0.2 g of ethylene glycol butyl ether acetate, 0.1 g of tert-butyl hydroquinone, 0.3 g of tea polyphenol, 0.1 g of ferulic acid and 0.5 g of Tween 80 were added into the mixture A obtained in step S1, and the mixture was stirred at 75°C for 1 h to obtain mixture B;

[0084] S3: 5.1 g of acrylic activator, 3.5 g of malic acid, 1.4 g of salicylic acid, 2 g of dimethyl thiourea and 0.05 g of polydimethylsiloxane were added into the mixture B obtained in step S2, and the pH was adjusted to 6. The mixture was stirred at 75°C for 3 h to obtain the high-efficiency flux.

[0085] The preparation method of the acrylic activator of the present example is as follows:

[0086] (1) 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 were added into a three-necked flask, warmed to 92°C for 9 h, filtered, N,N-dimethylformamide was removed by rotary evaporation, extracted by dichloromethane, washed by hydrochloric acid and deionized water, dried by anhydrous magnesium sulfate, and then passed through a chromatographic column to obtain compound A;

[0087] (2) 3.18 g of compound A, 8.6 g of methacrylic acid, 0.08 g of benzoyl peroxide and 65 mL of tetrahydrofuran were added into a three-necked flask, stirred for 30 min, warmed to 75°C for 10 h, tetrahydrofuran was removed by rotary evaporation, precipitated by n-hexane, filtered, washed by deionized water, dried in a vacuum drying box at 60°C for 10 h to obtain an acrylic activator.

[0088] Comparative Example 1

[0089] The difference between the present comparative example and Example 1 is that, in the preparation method of the acrylic activator of the present comparative example, styrene is used to replace an equal amount of compound A to react with methacrylic acid, and the rest is the same as Example 1.

[0090] Comparative Example 2

[0091] The difference between the present comparative example and Example 1 is that, in the present comparative example, the mass ratio of the acrylic activator, malic acid and salicylic acid is 2:5:3, and the rest is the same as Example 1.

[0092] Comparative Example 3

[0093] The difference between the present comparative example and Example 1 is that, in the present comparative example, the mass ratio of tert-butyl hydroquinone, tea polyphenol and ferulic acid is 3:1:1, and the rest is the same as Example 1.

[0094] Comparative Example 4

[0095] The difference between the present comparative example and Example 1 is that, in the present comparative example, the solvent is ethylene glycol, and the rest is the same as Example 1.

[0096] Comparative Example 5

[0097] The difference between the present comparative example and Example 1 is that, in the present comparative example, the high-efficiency flux is composed of the following components with the following mass:

[0098] Acrylic activator 1 g, malic acid 0.5 g, salicylic acid 1 g, dihexyl adipate 0.2 g, tert-butyl hydroquinone 0.1 g, ferulic acid 0.1 g, Tween 80 0.6 g, polydimethylsiloxane 0.2 g, polyethylene glycol 6000 3 g, ethylene glycol 9 g, isopropyl alcohol 3 g, and water 81.3 g.

[0099] Related performance test

[0100] According to the relevant test methods stipulated in the international standard IPC-TM-650, the relevant performance tests such as the expansion rate, copper plate corrosion, and surface insulation resistance of the above-mentioned examples 1-4 and comparative examples 1-5 were carried out, and the test results are shown in Table 1.

[0101] Table 1 Test results

[0102]

[0103] As can be seen from the comparison between comparative example 1 and example 1, the introduction of an imidazole ring into the acrylic activator can improve the surface insulation resistance, corrosion resistance and other properties of the flux.

[0104] As can be seen from the comparison between comparative example 2 and example 1, the reduction of the proportion of the acrylic activator may reduce the continuity of the film formed on the surface of the welding part, but due to the good wetting property of malic acid, this deficiency can be compensated to some extent, so that the influence on the expansion rate is not great; however, malic acid contains more hydroxyl and carboxyl groups, and has a certain polarity, and the increase of its amount will increase the polar groups, reduce the surface insulation property, and aggravate the corrosion of the copper plate.

[0105] As can be seen from the comparison between comparative example 3 and example 1, the performance of the flux is basically not affected, so the use of tea polyphenol and ferulic acid instead of can reduce the use amount of the synthetic antioxidant, i.e. tert-butyl hydroquinone.

[0106] As can be seen from the comparison between comparative example 4 and example 1, the use of ethylene glycol as the solvent can reduce the spreading property of the flux.

[0107] As can be seen from the comparison between comparative example 5 and example 1, the component and amount ratio of the high-efficiency flux are adjusted in the present comparative example, and the spreading property, corrosion resistance and other properties of the flux are reduced, which proves that the component and amount ratio of the high-efficiency flux of the present application has been optimized, and the change of the amount ratio and the replacement of the components will make the prepared flux worse.

[0108] The above has described the present application by way of examples, and it should be noted that any simple modification, change or other equivalent replacement which can be made by the person skilled in the art without creative labor, without departing from the core of the present application, falls within the protection scope of the present application.​

Claims

1. A high-efficiency fluxing agent, characterized by comprising: consists of the following components by mass percentage: 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 forming agent 3%-5%, solvent 10%-15%, and the balance being water; the organic acid activator is an acrylic acid activator, malic acid and salicylic acid are mixed in a mass ratio of (3-4):(1.5-2.5):1 to obtain the organic acid activator; The preparation method of the acrylic acid activator comprises the following steps: (1) uniformly mixing 2-ethyl imidazole, vinyl benzyl chloride, potassium carbonate and N,N-dimethyl formamide, heating and reacting, filtering, rotary evaporation, extraction, washing, drying, and passing through a chromatographic column to obtain compound A; (2) uniformly mixing compound A, methacrylic acid, an initiator and tetrahydrofuran, heating and reacting, rotary evaporation, separation, washing, and drying to obtain the acrylic acid activator. In the step (1), the molar ratio of 2-ethyl imidazole, vinyl benzyl 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 7-10h.

2. The flux according to claim 1, wherein In the step (2), the molar ratio of compound A and methacrylic acid is (1.1-1.5):1; the amount of the initiator 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 8-12h.

3. The flux according to claim 1, wherein The thiourea enhancer is selected from one or more of thiourea, methyl thiourea and dimethyl thiourea.

4. The flux according to claim 1, wherein The wetting agent is selected from one or more of ethylene glycol butyl ether acetate, diethyl succinate or dihexyl adipate.

5. The flux according to claim 1, wherein The antioxidant is prepared by mixing t-butyl hydroquinone, tea polyphenol and ferulic acid in a mass ratio of 1:(2-3):

1.

6. The flux according to claim 1, wherein The film forming agent is one or more of polyethylene glycol 1000, polyethylene glycol 2000, polyethylene glycol 4000 and polyethylene glycol 6000.

7. The flux according to claim 1, wherein The solvent is prepared by mixing ethylene glycol and isopropyl alcohol in a mass ratio of (2-3):

1.

8. The flux according to claim 1, wherein comprises the following steps:

9. A method of preparing a high efficiency flux according to any one of claims 1 to 8, wherein S1: uniformly mixing the film forming agent, the solvent and water at a temperature of 65-80°C to obtain a mixture A; S2: uniformly mixing the wetting agent, the antioxidant, the surfactant and the mixture A at a temperature of 65-80°C to obtain a mixture B; S3: uniformly mixing the organic acid activator, the thiourea enhancer and the defoaming agent with the mixture B, adjusting the pH to 6-7, and uniformly mixing at a temperature of 65-80°C to obtain the high-efficiency flux. ​

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