A high temperature halogen-free lead-free soldering flux and preparation method thereof

Abstract

The invention relates to the technical field of soldering flux, and discloses a high-temperature halogen-free lead-free soldering flux and a preparation method thereof. The soldering flux is prepared from the following ingredients: an organic solvent, modified rosin, benzotriazole, an organic amine, a thixotropic agent, an antioxidant, a surfactant and a corrosion inhibitor. The high-temperature halogen-free lead-free soldering flux prepared by the invention has the characteristics of being non-toxic and having no irritating odor. It is not only non-toxic and odorless at room temperature, but also does not generate toxic or irritating odorous substances during welding, and is green and safe.

Description

Technical Field

[0001] The invention relates to the technical field of soldering flux, in particular to a high-temperature halogen-free lead-free soldering flux and a preparation method thereof. Background Art

[0002] Halogen compounds are usually chlorine compounds or bromine compounds. After the solder paste containing chlorine compounds or bromine compounds completes its welding function, the chlorine compounds or bromine compounds will still exist in the applied electronic products in the form of residues. As the electronic products are used for a long time, chlorine compounds and bromine compounds will cause certain corrosion to the electronic products, thus affecting the reliability of the products.

[0003] For example, the Chinese invention patent with the prior art publication number CN104858571 B discloses a halogen-free soldering flux for tin-bismuth lead-free solder paste and a preparation method thereof. The present invention provides a halogen-free soldering flux for tin-bismuth lead-free solder paste and a preparation method thereof. The soldering flux is composed of 20-47% rosin, 8-20% tackifier, 0.5-12% antioxidant, 4-15% organic acid, 0.2-3% benzotriazole, 6-14% organic amine, 0.5-8% surfactant, 4-10% thixotropic agent and the remainder solvent. The soldering flux of the present invention optimizes and selects the active system of the soldering flux, so that the solder paste prepared by the soldering flux of the present invention and the tin-bismuth lead-free tin powder not only does not contain any fluorine, chlorine, bromine, iodine and astatine halogen elements, but also exhibits good solderability in brazing. After brazing, the solder joints are full and bright, no black oxide is generated, and the surface insulation resistance is high. It is particularly suitable for the assembly and welding of electronic components with low brazing temperature requirements. However, its expansion performance is poor, which limits its development.

[0004] Based on this, we propose a high-temperature halogen-free lead-free flux, hoping to solve the shortcomings of the existing technology. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a high-temperature halogen-free lead-free soldering flux and a preparation method thereof.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solutions:

[0007] A high-temperature halogen-free lead-free soldering flux is prepared from the following ingredients by weight: 30-50 parts of an organic solvent, 20-25 parts of modified rosin, 1-3 parts of benzotriazole, 1.5-2 parts of an organic amine, 1.2-1.8 parts of a thixotropic agent, 2-3 parts of an antioxidant, 1.8-2.6 parts of a surfactant, and 1-2 parts of a corrosion inhibitor.

[0008] As a further technical solution, the modified rosin preparation method comprises the following steps:

[0009] (1) adding methyl ethylene oxide to a reaction kettle, and then introducing dried trimethylamine, and after the introduction is completed within 2-3 hours, stirring the reaction for 1-2 hours, and always controlling the temperature in the reaction kettle at 20-25° C. After the reaction is completed, filtering and separating to obtain a reaction product, washing the reaction product with acetone, and vacuum drying to obtain a white reaction material;

[0010] The trimethylamine drying treatment temperature is 50-60°C and the drying time is 2-3h;

[0011] (2) Add rosin, white reaction material, and modified turpentine oil to a reactor in sequence, introduce inert gas into the reactor, exhaust the air in the reactor, then add anhydrous ethanol, stir evenly, heat to the ethanol reflux temperature, react for 2-3 hours, and then perform rotary evaporation on the mixed liquid in the reactor to recover the ethanol to obtain modified rosin.

[0012] As a further technical solution, the molar ratio of methyl ethylene oxide to trimethylamine is 10:3-4.

[0013] As a further technical solution: the mass ratio of the rosin, white reaction material, modified turpentine and anhydrous ethanol is 30-35:3-5:5-7:45-50.

[0014] As a further technical solution, the modified turpentine preparation method comprises the following steps:

[0015] The turpentine oil is dried to obtain dry turpentine oil;

[0016] Add dry turpentine and propylene oxide to the reactor in sequence, then add glycerol, stir for 30-40 minutes, then add the catalyst, adjust the temperature to 80-88°C, keep warm and stir for 2-3 hours. After the reaction is completed, cool to room temperature, extract the reactants with n-hexane for 3 times, combine the extracts, and then wash with water for 3 times. After drying, recover the n-hexane by rotary evaporation to obtain modified turpentine.

[0017] As a further technical solution, the mass ratio of the turpentine oil, propylene oxide, glycerol and catalyst is 20-24:3-7:25-30:0.8-1.2.

[0018] As a further technical solution: the catalyst is potassium hydroxide.

[0019] As a further technical solution: the organic amine is diisopropanolamine;

[0020] The thixotropic agent is N,N-ethylene bisstearamide;

[0021] The surfactant is sodium dodecylbenzene sulfonate;

[0022] The antioxidant is 2,6-di-tert-butyl-4-methylphenol;

[0023] The corrosion inhibitor is sodium molybdate;

[0024] The organic solvent is ethylene glycol.

[0025] A method for preparing a high-temperature halogen-free lead-free soldering flux comprises the following steps:

[0026] (1) Weigh each component by weight and set aside;

[0027] (2) Add two equal parts of organic solvent, ab;

[0028] (3) Add benzotriazole and organic amine to the organic solvent in part (a) in sequence, adjust the temperature to 50-60°C, stir at this temperature for 40-50 minutes, and let it stand;

[0029] (4) adding modified rosin to step (3), adjusting the temperature to 120-140° C., stirring at this temperature for 35-40 min, and cooling naturally to room temperature to obtain an intermediate;

[0030] (5) Add the thixotropic agent, antioxidant, surfactant and corrosion inhibitor to the organic solvent in part (b) in sequence, heat to 105-110° C., and stir for 30-35 minutes to obtain a mixed solution;

[0031] (6) Add the mixed solution obtained above to the intermediate, adjust the temperature to 80-90° C., keep warm and stir for 1-2 hours, then cool naturally to room temperature and stand for 40-50 minutes to obtain the product.

[0032] The halogen-free lead-free soldering flux prepared by the present invention can assist the solder in spreading on the substrate and can promote the smooth progress of the soldering process. When electronic packaging is performed by using soft soldering, oxides or impurities may exist on the surface of the substrate to be soldered, which may directly hinder the expansion of the molten solder on the substrate. After adopting the halogen-free lead-free soldering flux of the present invention, the oxides and impurities can be removed to promote the spreading of the molten solder. At the same time, a protective film can be formed on the molten solder and the substrate during soldering to prevent them from being oxidized again.

[0033] The invention can improve the heat transfer efficiency of the soldering flux by introducing the modified rosin, can better transfer the heat to the area to be soldered, thereby greatly improving the soldering efficiency, and also has good thermal stability. The invention can greatly improve the diffusion speed of the halogen-free lead-free soldering flux by modifying the rosin, and the diffusion speed of the soldering flux directly determines the spreading speed of the solder, which in turn directly affects the soldering efficiency. The diffusion speed of the soldering flux is greatly improved, thereby significantly improving the soldering efficiency.

[0034] The modified turpentine is introduced into the preparation of the modified rosin, so that the activity of the modified rosin in a liquid state can be further improved, and the modified rosin can react with the metal oxide faster to form a reaction salt, thereby achieving the effect of removing the metal oxide film. In addition, the molten modified rosin has better fluidity and thermal conductivity, and can reduce the occurrence of poor welding. In addition, during welding, the secondary oxidation of the metal can be prevented. At the same time, the hydrophobic film formed during welding can play an excellent waterproof and moisture-proof function.

[0035] Compared with the prior art, the present invention provides a high-temperature halogen-free lead-free soldering flux and a preparation method thereof, which has the following beneficial effects:

[0036] The high-temperature halogen-free lead-free soldering flux prepared by the present invention is non-toxic and has no irritating odor. It is not only non-toxic and odorless at room temperature, but also does not generate toxic or irritating odor substances during welding. It is green and safe. The residue after welding is easy to remove and will not have an adverse effect on the solder joint. It can be stored for a long time at room temperature, thereby extending its shelf life. DETAILED DESCRIPTION

[0037] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] The following are specific embodiments:

[0039] Example 1

[0040] A high-temperature halogen-free lead-free soldering flux is prepared from the following ingredients by weight: 30 parts of an organic solvent, 20 parts of modified rosin, 1 part of benzotriazole, 1.5 parts of an organic amine, 1.2 parts of a thixotropic agent, 2 parts of an antioxidant, 1.8 parts of a surfactant, and 1 part of a corrosion inhibitor.

[0041] As a further technical solution, the modified rosin preparation method comprises the following steps:

[0042] (1) adding methyl ethylene oxide to a reaction kettle, and then introducing dried trimethylamine, and after the introduction is completed within 2 hours, stirring the reaction for 1 hour, and always controlling the temperature in the reaction kettle at 20° C. After the reaction is completed, filtering and separating to obtain a reaction product, washing the reaction product with acetone, and vacuum drying to obtain a white reaction material;

[0043] The trimethylamine drying treatment temperature is 50°C and the drying time is 2h;

[0044] (2) Add rosin, white reaction material, and modified turpentine oil to a reactor in sequence, introduce inert gas into the reactor, exhaust the air in the reactor, and then add anhydrous ethanol, stir evenly, heat to the ethanol reflux temperature, react for 2 hours, and then perform rotary evaporation on the mixed liquid in the reactor to recover ethanol to obtain modified rosin.

[0045] As a further technical solution, the molar ratio of methyl ethylene oxide to trimethylamine is 10:3.

[0046] As a further technical solution: the rosin, white reaction material, modified turpentine and anhydrous ethanol are mixed in a mass ratio of 30:3:5:45.

[0047] As a further technical solution, the modified turpentine preparation method comprises the following steps:

[0048] The turpentine oil is dried to obtain dry turpentine oil;

[0049] Add dry turpentine and propylene oxide to the reactor in sequence, then add glycerol, stir for 30 minutes, then add the catalyst, adjust the temperature to 80°C, keep stirring for 2 hours, after the reaction is completed, cool to room temperature, extract the reactants with n-hexane for 3 times, combine the extracts, and then wash with water for 3 times. After drying, recover the n-hexane by rotary evaporation to obtain modified turpentine.

[0050] As a further technical solution, the mass ratio of the turpentine oil, propylene oxide, glycerol and catalyst is 20:3:25:0.8.

[0051] As a further technical solution: the catalyst is potassium hydroxide.

[0052] As a further technical solution: the organic amine is diisopropanolamine;

[0053] The thixotropic agent is N,N-ethylene bisstearamide;

[0054] The surfactant is sodium dodecylbenzene sulfonate;

[0055] The antioxidant is 2,6-di-tert-butyl-4-methylphenol;

[0056] The corrosion inhibitor is sodium molybdate;

[0057] The organic solvent is ethylene glycol.

[0058] A method for preparing a high-temperature halogen-free lead-free soldering flux comprises the following steps:

[0059] (1) Weigh each component by weight and set aside;

[0060] (2) Add two equal parts of organic solvent, ab;

[0061] (3) Add benzotriazole and organic amine to the organic solvent in part (a) in sequence, adjust the temperature to 50°C, stir and keep warm for 40 minutes, and let it stand;

[0062] (4) adding modified rosin to step (3), adjusting the temperature to 120° C., stirring at this temperature for 35 min, and naturally cooling to room temperature to obtain an intermediate;

[0063] (5) Add a thixotropic agent, an antioxidant, a surfactant, and a corrosion inhibitor to the organic solvent in part (b) in sequence, heat to 105° C., and stir at this temperature for 30 minutes to obtain a mixed solution;

[0064] (6) The mixed solution obtained above was added to the intermediate, the temperature was adjusted to 80°C, the mixture was stirred for 1 hour, and then naturally cooled to room temperature and allowed to stand for 40 minutes to obtain the product.

[0065] Example 2

[0066] A high-temperature halogen-free lead-free soldering flux is prepared from the following ingredients by weight: 40 parts of an organic solvent, 22 parts of modified rosin, 2 parts of benzotriazole, 1.8 parts of an organic amine, 1.5 parts of a thixotropic agent, 2.5 parts of an antioxidant, 2.3 parts of a surfactant, and 1.2 parts of a corrosion inhibitor.

[0067] As a further technical solution, the modified rosin preparation method comprises the following steps:

[0068] (1) adding methyl ethylene oxide to a reaction kettle, and then introducing dried trimethylamine, and after the introduction is completed within 2.3 hours, stirring the reaction for 1.2 hours, and always controlling the temperature in the reaction kettle at 22° C. After the reaction is completed, filtering and separating to obtain a reaction product, washing the reaction product with acetone, and vacuum drying to obtain a white reaction material;

[0069] The trimethylamine drying treatment temperature is 55°C and the drying time is 2.5h;

[0070] (2) Add rosin, white reaction material, and modified turpentine oil to a reactor in sequence, introduce inert gas into the reactor, exhaust the air in the reactor, and then add anhydrous ethanol, stir evenly, heat to the ethanol reflux temperature, react for 2.5 hours, and then perform rotary evaporation on the mixed liquid in the reactor to recover ethanol to obtain modified rosin.

[0071] As a further technical solution, the molar ratio of methyl ethylene oxide to trimethylamine is 10:3.5.

[0072] As a further technical solution: the mass ratio of the rosin, white reaction material, modified turpentine and anhydrous ethanol is 32:4:6:49.

[0073] As a further technical solution, the modified turpentine preparation method comprises the following steps:

[0074] The turpentine oil is dried to obtain dry turpentine oil;

[0075] Add dry turpentine and propylene oxide to the reactor in sequence, and then add glycerol, stir for 35 minutes, then add the catalyst, adjust the temperature to 82°C, keep stirring for 2.5 hours. After the reaction is completed, cool to room temperature, extract the reactants with n-hexane for 3 times, combine the extracts, and then wash with water for 3 times. After drying, recover the n-hexane by rotary evaporation to obtain modified turpentine.

[0076] As a further technical solution, the mixing mass ratio of the turpentine oil, propylene oxide, glycerol and catalyst is 22:5:28:0.9.

[0077] As a further technical solution: the catalyst is potassium hydroxide.

[0078] As a further technical solution: the organic amine is diisopropanolamine;

[0079] The thixotropic agent is N,N-ethylene bisstearamide;

[0080] The surfactant is sodium dodecylbenzene sulfonate;

[0081] The antioxidant is 2,6-di-tert-butyl-4-methylphenol;

[0082] The corrosion inhibitor is sodium molybdate;

[0083] The organic solvent is ethylene glycol.

[0084] A method for preparing a high-temperature halogen-free lead-free soldering flux comprises the following steps:

[0085] (1) Weigh each component by weight and set aside;

[0086] (2) Add two equal parts of organic solvent, ab;

[0087] (3) Add benzotriazole and organic amine to the organic solvent in part (a) in sequence, adjust the temperature to 55°C, stir and keep warm for 45 minutes, and let it stand;

[0088] (4) adding modified rosin to step (3), adjusting the temperature to 130° C., stirring at this temperature for 38 min, and naturally cooling to room temperature to obtain an intermediate;

[0089] (5) Add a thixotropic agent, an antioxidant, a surfactant, and a corrosion inhibitor to the organic solvent in part (b) in sequence, heat to 107° C., and stir at this temperature for 32 minutes to obtain a mixed solution;

[0090] (6) The mixed solution obtained above was added to the intermediate, the temperature was adjusted to 85°C, the mixture was kept warm and stirred for 1.5 hours, and then naturally cooled to room temperature and allowed to stand for 42 minutes to obtain the product.

[0091] Example 3

[0092] A high-temperature halogen-free lead-free soldering flux is prepared from the following ingredients by weight: 50 parts of an organic solvent, 25 parts of modified rosin, 3 parts of benzotriazole, 2 parts of an organic amine, 1.8 parts of a thixotropic agent, 3 parts of an antioxidant, 2.6 parts of a surfactant, and 2 parts of a corrosion inhibitor.

[0093] As a further technical solution, the modified rosin preparation method comprises the following steps:

[0094] (1) adding methyl ethylene oxide to a reaction kettle, and then introducing dried trimethylamine, and after the introduction is completed within 3 hours, stirring the reaction for 2 hours, and always controlling the temperature in the reaction kettle at 25° C. After the reaction is completed, filtering and separating to obtain a reaction product, washing the reaction product with acetone, and vacuum drying to obtain a white reaction material;

[0095] The trimethylamine drying treatment temperature is 60°C and the drying time is 3h;

[0096] (2) Add rosin, white reaction material, and modified turpentine oil to a reactor in sequence, introduce inert gas into the reactor, exhaust the air in the reactor, and then add anhydrous ethanol, stir evenly, heat to the ethanol reflux temperature, react for 3 hours, and then perform rotary evaporation on the mixed liquid in the reactor to recover ethanol to obtain modified rosin.

[0097] As a further technical solution, the molar ratio of methyl ethylene oxide to trimethylamine is 10:4.

[0098] As a further technical solution: the rosin, white reaction material, modified turpentine and anhydrous ethanol are mixed in a mass ratio of 35:5:7:50.

[0099] As a further technical solution, the modified turpentine preparation method comprises the following steps:

[0100] The turpentine oil is dried to obtain dry turpentine oil;

[0101] Add dry turpentine and propylene oxide to the reactor in sequence, and then add glycerol and stir for 40 minutes. Then add the catalyst, adjust the temperature to 88°C, keep stirring for 3 hours. After the reaction is completed, cool to room temperature, extract the reactants with n-hexane for 3 times, combine the extracts, and then wash with water for 3 times. After drying, recover the n-hexane by rotary evaporation to obtain modified turpentine.

[0102] As a further technical solution, the mass ratio of the turpentine oil, propylene oxide, glycerol and catalyst is 24:7:30:1.2.

[0103] As a further technical solution: the catalyst is potassium hydroxide.

[0104] As a further technical solution: the organic amine is diisopropanolamine;

[0105] The thixotropic agent is N,N-ethylene bisstearamide;

[0106] The surfactant is sodium dodecylbenzene sulfonate;

[0107] The antioxidant is 2,6-di-tert-butyl-4-methylphenol;

[0108] The corrosion inhibitor is sodium molybdate;

[0109] The organic solvent is ethylene glycol.

[0110] A method for preparing a high-temperature halogen-free lead-free soldering flux comprises the following steps:

[0111] (1) Weigh each component by weight and set aside;

[0112] (2) Add two equal parts of organic solvent, ab;

[0113] (3) Add benzotriazole and organic amine to the organic solvent in part (a) in sequence, adjust the temperature to 60°C, stir and keep warm for 50 minutes, and let it stand;

[0114] (4) adding modified rosin to step (3), adjusting the temperature to 140° C., stirring at this temperature for 40 min, and cooling naturally to room temperature to obtain an intermediate;

[0115] (5) Add a thixotropic agent, an antioxidant, a surfactant, and a corrosion inhibitor to the organic solvent in part (b) in sequence, heat to 110° C., and stir at this temperature for 35 minutes to obtain a mixed solution;

[0116] (6) The mixed solution obtained above was added to the intermediate, the temperature was adjusted to 90°C, the mixture was stirred for 2 hours, and then naturally cooled to room temperature and allowed to stand for 50 minutes to obtain the product.

[0117] Comparative Example 1: The difference from Example 1 is that the modified rosin is replaced by unmodified rosin;

[0118] Comparative Example 2: The difference from Example 1 is that unmodified turpentine is used in the modified rosin;

[0119] test:

[0120] The size and irritation of the smoke are judged by visual inspection and smelling the medicine in the laboratory:

[0121] Table 1

[0122] Smoke (large, small) Example 1 Small smoke Example 2 Small smoke Example 3 Small smoke Comparative Example 1 Heavy smoke Comparative Example 2 Slightly more smoke

[0123] It can be seen from Table 1 that the generation of smoke is significantly reduced after the soldering flux prepared by the present invention is used.

[0124] Table 2

[0125]

[0126]

[0127] It can be seen from Table 2 that the soldering flux prepared by the method of the present invention has no irritating odor.

[0128] The storage performance of the embodiment and the comparative example samples was compared:

[0129] Stored in a sealed container at 0-10℃ for 6 months, the viscosity increase rate of each group is compared:

[0130] Viscosity increase rate = (test viscosity - initial viscosity) / initial viscosity × 100%:

[0131] Table 3

[0132] Viscosity increase rate / % Example 1 2.35 Example 2 2.28 Example 3 2.33 Comparative Example 1 10.87 Comparative Example 2 8.21

[0133] It can be seen from Table 3 that the viscosity of the soldering flux prepared by the method of the present invention changes little after long-term storage, which shows that it has a long shelf life, indicating that the storage property of the soldering flux can be greatly improved by modifying the rosin.

[0134] The spreading performance of the samples of the embodiments and comparative examples was tested in accordance with SJ / T11273-2002;

[0135] Table 4

[0136] <![CDATA[Spreading area / mm 2 > Example 1 62.34 Example 2 63.58 Example 3 62.76 Comparative Example 1 46.27 Comparative Example 2 55.14

[0137] It can be seen from Table 4 that the soldering flux prepared by the method of the present invention has excellent spreading performance.

[0138] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A high temperature halogen-free lead-free soldering flux, characterized in that: The composition is made of the following ingredients by weight: 30-50 parts of organic solvent, 20-25 parts of modified rosin, 1-3 parts of benzotriazole, 1.5-2 parts of organic amine, 1.2-1.8 parts of thixotropic agent, 2-3 parts of antioxidant, 1.8-2.6 parts of surfactant, and 1-2 parts of corrosion inhibitor; The modified rosin preparation method comprises the following steps: (1) Add methyl ethylene oxide to a reaction kettle, and then introduce dried trimethylamine. After the introduction is completed within 2-3 hours, stir the reaction for 1-2 hours, and always control the temperature in the reaction kettle at 20-25°C. After the reaction is completed, filter and separate to obtain a reaction product. Wash the reaction product with acetone, and vacuum dry to obtain a white reaction material. The trimethylamine drying treatment temperature is 50-60°C and the drying time is 2-3h; (2) Add rosin, white reaction material and modified turpentine oil to a reactor in sequence, introduce inert gas into the reactor, exhaust the air in the reactor, then add anhydrous ethanol, stir evenly, heat to the reflux temperature of ethanol, react for 2-3 hours, and then perform rotary evaporation on the mixed liquid in the reactor to recover ethanol to obtain modified rosin; The molar ratio of methyl ethylene oxide to trimethylamine is 10:3-4; The modified turpentine preparation method comprises the following steps: The turpentine oil is dried to obtain dry turpentine oil; Add dry turpentine and propylene oxide to the reactor in sequence, then add glycerol, stir for 30-40 minutes, then add the catalyst, adjust the temperature to 80-88°C, keep warm and stir for 2-3 hours. After the reaction is completed, cool to room temperature, extract the reactants with n-hexane for 3 times, combine the extracts, and then wash with water for 3 times. After drying, recover the n-hexane by rotary evaporation to obtain modified turpentine.

2. A high temperature halogen-free lead-free soldering flux according to claim 1, characterized in that: The mixing mass ratio of the rosin, the white reaction material, the modified turpentine and the anhydrous ethanol is 30-35:3-5:5-7:45-50.

3. A high temperature halogen-free lead-free soldering flux according to claim 1, characterized in that: The mixing mass ratio of the turpentine oil, propylene oxide, glycerol and catalyst is 20-24:3-7:25-30:0.8-1.

2.

4. A high temperature halogen-free lead-free soldering flux according to claim 3, characterized in that: The catalyst is potassium hydroxide.

5. The high temperature halogen-free lead-free soldering flux according to claim 1, characterized in that: The organic amine is diisopropanolamine; The thixotropic agent is N,N-ethylene bisstearamide; The surfactant is sodium dodecylbenzene sulfonate; The antioxidant is 2,6-di-tert-butyl-4-methylphenol; The corrosion inhibitor is sodium molybdate; The organic solvent is ethylene glycol.

6. A method for preparing a high temperature halogen-free lead-free soldering flux according to any one of claims 1 to 5, characterized in that: The following steps are involved: (1) Weigh each component by weight and set aside; (2) Add two equal parts of organic solvent, ab; (3) Add benzotriazole and organic amine to the organic solvent in part (a) in sequence, adjust the temperature to 50-60°C, stir and keep warm for 40-50 minutes, and let it stand; (4) Add modified rosin to step (3), adjust the temperature to 120-140°C, keep stirring for 35-40 minutes, and cool naturally to room temperature to obtain an intermediate; (5) Add the thixotropic agent, antioxidant, surfactant and corrosion inhibitor to the organic solvent in part (b) in sequence, heat to 105-110°C, and stir at this temperature for 30-35 minutes to obtain a mixed solution; (6) Add the mixed solution obtained above to the intermediate, adjust the temperature to 80-90°C, keep stirring for 1-2 hours, then cool naturally to room temperature and let stand for 40-50 minutes to obtain the product.

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