An environmentally friendly and highly stable flux and its preparation method

Abstract

This invention relates to the field of flux, specifically disclosing an environmentally friendly, highly stable flux. The raw materials, by weight, include: 8-10 parts triethanolamine, 3-5 parts petrolatum, 5-8 parts cyclohexane citric acid, 0.1-1 parts corrosion inhibitor, 5-8 parts solvent, 1-3 parts coumarone resin, 5-8 parts hydroxyl acrylic resin, 1-2 parts vinyltriethoxysilane, 2-6 parts tetraethyl orthosilicate, 1-2 parts cholesterol, 0.1-0.5 parts phospholipid, 0.1-0.3 parts dicumyl peroxide, 1-3 parts polyamide monomer, 3-5 parts brucite fiber, 0.5-1.0 parts sodium stearate, 1-2 parts hydrogenated castor oil, and 1-2 parts zinc dichloride. This invention also discloses a method for preparing the environmentally friendly, highly stable flux, using organic compounds to activate silicon spheres and multiple effective components, effectively enhancing the stability of the system and improving the flux's performance.

Description

Technical Field

[0001] This invention relates to the field of flux technology, and in particular to environmentally friendly, highly stable fluxes and their preparation methods. Background Technology

[0002] Soldering is a major process in electronic assembly. Flux is an auxiliary material that ensures the smooth progress of the soldering process. The main function of flux is to remove oxides from the surface of the solder and the base material being soldered, so that the metal surface reaches the necessary cleanliness. It prevents the surface from oxidizing again during soldering, reduces the surface tension of the solder, and improves the soldering performance.

[0003] The quality of flux directly affects the quality of electronic products. With the rapid development of industrial production, the requirements for welding effect are getting higher and higher. Existing fluxes are prone to producing toxic and harmful substances during use, which can easily cause environmental pollution. If they come into contact with open flames or high-temperature heat sources, they can easily cause fires or explosions. At the same time, in actual use, they often need to have better stability and wetting and ductility.

[0004] CN101157168A discloses a rosin-based halogen-free no-clean flux for lead-free solder wire, composed of the following substances by mass percentage: 4-18% organic acid activator, 10-30% organic solvent, 1-6% paste-forming agent, 0.2-3% stabilizer, 0.5-5% thixotropic agent, 0.5-4% surfactant, 0.5-5% corrosion inhibitor, and modified rosin as the balance. This flux is halogen-free and has a high insulation resistance after soldering. However, its paste-forming agent is one or more of polyethylene glycol 2000, polyethylene glycol 4000, or polyethylene glycol 6000. Polyethylene glycol undergoes thermal decomposition during the soldering process, and all its products are volatile. Therefore, the soldering process produces a large amount of smoke, which is harmful to human health and pollutes the environment.

[0005] CN104117787A discloses an environmentally friendly no-clean flux, comprising the following components by mass percentage: aspartic acid 1.0-4.0%, lactic acid 0.4-1.0%, gallic acid 0.4-1.2%, ethyl lactate 2-8%, ethanol 5-15%, glycerol 6-12%, propylene glycol monomethyl ether propionate 0.3-1.5%, surfactant 0.4-2.2%, corrosion inhibitor 0.2-1.6%, with the balance being deionized water. This environmentally friendly no-clean flux is prepared using deionized water as a solvent, aspartic acid, lactic acid, and gallic acid as activators, ethyl lactate, ethanol, and glycerol as co-solvents, and propylene glycol monomethyl ether propionate as a film-forming agent. While this flux meets environmental requirements, its components are prone to change under high-temperature conditions, the activator is easily decomposed, and its stability is poor.

[0006] CN 108098189 A discloses an environmentally friendly flux comprising the following components in parts by weight: 15-30 parts hydrogenated castor oil, 80-150 parts disproportionated rosin, 100-120 parts epoxy resin, 10-15 parts nano-calcium oxide, 10-30 parts acetone, 20-30 parts organic esters, 5-30 parts o-hydroxybenzoic acid, 50-80 parts organic ethers, and 0.5-2.5 parts benzotriazole. The flux, prepared by combining hydrogenated castor oil, nano-calcium oxide, and disproportionated rosin with other substances, is lead-free and halogen-free, resulting in minimal environmental pollution. However, the rosin derivatives in the flux are volatile and can generate bubbles, affecting soldering quality. Furthermore, high-viscosity flux makes oxide diffusion difficult, increasing the pressure for bubble generation and leading to more bubbles, further impacting solder joint quality.

[0007] Currently, the quality of casting and welding is closely related to the flux. However, current fluxes not only easily pollute the environment and are harmful to human health, but also have poor stability and poor wetting and ductility, which affects the casting and welding effect, resulting in mediocre flux performance. Therefore, how to develop an environmentally friendly flux to solve the above problems has become a technical issue that needs to be addressed. Summary of the Invention

[0008] The purpose of this invention is to address the shortcomings of existing technologies by proposing an environmentally friendly radiation-proof coating for buildings and its preparation method.

[0009] An environmentally friendly and highly stable flux, the raw materials by weight are: 8-10 parts triethanolamine, 3-5 parts petrolatum, 5-8 parts cyclohexane citric acid, 0.1-1 parts corrosion inhibitor, 5-8 parts solvent, 1-3 parts coumarone resin, 5-8 parts hydroxyl acrylic resin, 1-2 parts vinyltriethoxysilane, 2-6 parts tetraethyl orthosilicate, 1-2 parts cholesterol, 0.1-0.5 parts phospholipid, 0.1-0.3 parts dicumyl peroxide, 1-3 parts polyamide monomer, 3-5 parts brucite fiber, 0.5-1.0 parts sodium stearate, 1-2 parts hydrogenated castor oil, and 1-2 parts zinc dichloride.

[0010] Preferably, the corrosion inhibitor is rosin-amine imidazoline.

[0011] Preferably, the solvent is at least one selected from methanol, ethanol, ethyl acetate, and propylene glycol.

[0012] Preferably, the polyamide monomers include linolenic acid and ethylenediamine, with a weight ratio of linolenic acid to ethylenediamine of 1-2:1-2.

[0013] Preferably, the brucite fiber particle size is 20-30 nm and the aspect ratio is 20-25:1.

[0014] Preferably, the phospholipid is lecithin.

[0015] The above-mentioned method for preparing environmentally friendly and highly stable flux includes the following steps:

[0016] S1. Mix triethanolamine, petrolatum, cyclohexane citric acid, corrosion inhibitor, and solvent, and stir at 40-50℃ for 10-20 minutes to obtain preform a;

[0017] S2. Mix coumarone resin and hydroxyl acrylic resin, stir at 90-100℃ for 20-30 minutes, cool to 40-50℃, add to preform a and stir evenly to obtain preform b.

[0018] S3. Add vinyltriethoxysilane, tetraethyl orthosilicate, cholesterol, and phospholipids to chloroform and stir until homogeneous. Remove chloroform by rotary evaporation and add to phosphate buffer. Sonicate at 10-30℃ for 1-2 hours. Use an extruder to pass the mixture through a 100-500nm pore size filter membrane to an ammonia solution with a pH of 8-9. Let stand at 50-60℃ for 15-30 hours, centrifuge, wash, and vacuum dry to obtain activated silicon spheres.

[0019] S4. Add activated silica spheres and dicumyl peroxide to ethanol and stir evenly. Add polyamide monomer to it and react at 65-75℃ for 20-24 hours under nitrogen protection. Centrifuge, wash with water 2-3 times, and vacuum dry to obtain polyamide silica composite microspheres.

[0020] S5. Add magnesium hydroxide fiber and sodium stearate to water and stir for 1-2 hours. Add silica composite microspheres and sonicate at 40-50℃ for 1-2 hours. Cool to room temperature, filter, wash, vacuum dry, pulverize, add hydrogenated castor oil and zinc dichloride, and pre-mixed material b, and mix evenly to obtain an environmentally friendly and highly stable flux.

[0021] Preferably, in S3, the concentration of the phosphate buffer solution is 0.01-0.02 mol / L, and the pH is 6-6.5.

[0022] Preferably, in S3, the ultrasonic frequency is 10-15 kHz.

[0023] Preferably, in S5, the ultrasonic frequency is 12-18 kHz.

[0024] Beneficial effects:

[0025] In this invention, triethanolamine and cyclohexane citric acid are combined. With the synergistic effect of petrolatum, this can effectively prevent flux from spreading and causing an oxide film to form on the surface of the welded parts, thereby increasing the flux's antioxidant properties.

[0026] This invention employs a compound of tetraethyl orthosilicate and vinyltriethoxysilane, which not only exhibits good dispersibility with phospholipids and cholesterol, but also, due to the hydrophobic nature of both, confines the compounds within the hydrophobic bilayer of phospholipids and cholesterol. After hydrolysis, these compounds undergo in-situ condensation to form vinyl-containing silicon spheres. These activated silicon spheres are then copolymerized with linolenic acid and ethylenediamine to obtain polyamide-silica composite microspheres with a vesicle structure. The surface of these microspheres has low cross-linking density grafts and exhibits a linear chain structure, which can reduce bubble generation and smoke generation during welding, effectively improving system stability. Furthermore, when combined with layered magnesium hydroxide fibers, it can significantly improve the wetting and spreading properties of the flux.

[0027] This invention uses a combination of environmentally friendly organic amine triethanolamine and cyclohexane citric acid as activators to synergistically activate silicon spheres. Combined with the sustained-release effect of vesicles, it not only has long-lasting antioxidant properties and effectively improves the wettability of welding materials, but also better and more evenly wets the welding surface during the welding process, effectively enhancing the stability and insulation of the flux.

[0028] This invention uses rosin amine imidazoline as a corrosion inhibitor, which is environmentally friendly. The hydrophobic structure of the nonpolar tricyclic structure of rosin amine and the hydrophilic amine group have a high affinity for activated silicon balls. This not only significantly increases the stability of the flux, but also provides excellent insulation and mechanical properties.

[0029] This invention is not only environmentally friendly and has minimal odor, but also exhibits good stability in practical applications, effectively enhancing the storage stability of the system, improving the flux's performance, and extending its service life. Furthermore, the preparation method is simple and suitable for large-scale production applications. Attached Figure Description

[0030] Figure 1 The image shows a comparison of wetting times of the environmentally friendly, highly stable flux obtained in Example 5 and Comparative Examples 1-2.

[0031] Figure 2 The image shows a comparison of the wetting power of the environmentally friendly, highly stable fluxes obtained in Example 5 and Comparative Examples 1-2.

[0032] Figure 3 This is a comparison chart of the spread rate of the environmentally friendly and highly stable flux obtained using Example 5 and Comparative Examples 1-2.

[0033] Figure 4 The graph shows a comparison of the insulation properties of the environmentally friendly, highly stable fluxes obtained in Example 5 and Comparative Examples 1-2.

[0034] Figure 5 This is a comparison chart of the stability of the environmentally friendly, highly stable fluxes obtained using Example 5 and Comparative Examples 1-2. Detailed Implementation

[0035] The present invention will be further explained below with reference to specific embodiments.

[0036] The magnesia fiber used below was purchased from Lingshou County Moujia Mineral Products Co., Ltd.; the cyclohexane citric acid used below was purchased from Dongguan Mouyu Chemical Co., Ltd.; the rosin imidazoline used below was purchased from Guangzhou Moubao Chemical Co., Ltd.; and the coumarone resin used below was purchased from Wuhan Moulisheng Chemical Co., Ltd.

[0037] Example 1

[0038] A method for preparing an environmentally friendly and highly stable flux includes the following steps:

[0039] S1. Mix 8g triethanolamine, 3g petrolatum, 5g cyclohexane citric acid, 0.1g rosin imidazoline, and 5g methanol, and stir at 50℃ for 20 minutes to obtain preform a;

[0040] S2. Mix 1g of coumarone resin and 5g of hydroxyl acrylic resin, stir at 100℃ for 30min, cool to 50℃, add to preform a and stir evenly to obtain preform b.

[0041] S3. Add 1g vinyltriethoxysilane, 2g tetraethyl orthosilicate, 1g cholesterol, and 0.1g lecithin to 5g chloroform and stir well. Remove the chloroform by rotary evaporation. Add the mixture to a 0.01mol / L phosphate buffer solution with a pH of 6. Sonicate at 30℃ for 1h at a frequency of 15kHz. Use an extruder to pass the mixture through a 100nm filter membrane into an ammonia solution with a pH of 9. Let it stand at 50℃ for 15h, centrifuge, wash, and vacuum dry to obtain activated silica spheres.

[0042] S4. Add activated silica spheres and 0.1g dicumyl peroxide to 20g ethanol and stir evenly. Add 0.5g linolenic acid and 0.5g ethylenediamine to the mixture. Under nitrogen protection, react at 65℃ for 24h. Centrifuge, wash with water 3 times, and vacuum dry to obtain polyamide silica composite microspheres.

[0043] S5. Add 3g of magnesium hydroxide fiber with a particle size of 20nm and an aspect ratio of 20:1 and 0.5g of sodium stearate to 5g of water and stir for 1h at a stirring speed of 300r / min. Add silica composite microspheres and sonicate at 50℃ for 1h at a sonication frequency of 18kHz. Cool to room temperature, filter, wash, vacuum dry, pulverize, add 1g of hydrogenated castor oil and 1g of zinc dichloride and pre-mixed material b, and mix evenly to obtain an environmentally friendly and highly stable flux.

[0044] Example 2

[0045] A method for preparing an environmentally friendly and highly stable flux includes the following steps:

[0046] S1. Mix 10g triethanolamine, 5g petrolatum, 8g cyclohexane citric acid, 1g rosin aminoimidazoline, 4g ethyl acetate, and 4g ethanol, and stir at 50℃ for 20min to obtain preform a.

[0047] S2. Mix 3g of coumarone resin and 8g of hydroxyl acrylic resin, stir at 100℃ for 30min, cool to 50℃, add to preform a and stir evenly to obtain preform b.

[0048] S3. Add 2g vinyltriethoxysilane, 6g tetraethyl orthosilicate, 2g cholesterol, and 0.5g lecithin to 5g chloroform and stir well. Remove the chloroform by rotary evaporation. Add the mixture to a 0.01mol / L phosphate buffer solution with a pH of 6. Sonicate at 30℃ for 1h at a frequency of 15kHz. Use an extruder to pass the mixture through a 100nm filter membrane into an ammonia solution with a pH of 9. Let it stand at 50℃ for 15h, centrifuge, wash, and vacuum dry to obtain activated silicon spheres.

[0049] S4. Add activated silica spheres and 0.3g dicumyl peroxide to 40g ethanol and stir evenly. Add 1.5g linolenic acid and 1.5g ethylenediamine to the mixture. Under nitrogen protection, react at 65℃ for 24h. Centrifuge, wash with water 3 times, and vacuum dry to obtain polyamide silica composite microspheres.

[0050] S5. Add 5g of magnesium hydroxide fiber with a particle size of 20nm and an aspect ratio of 20:1 and 1g of sodium stearate to 5g of water and stir for 1h at a stirring speed of 300r / min. Add silica composite microspheres and sonicate at 50℃ for 1h at a sonication frequency of 18kHz. Cool to room temperature, filter, wash, vacuum dry, pulverize, add 2g of hydrogenated castor oil and 2g of zinc dichloride and pre-made material b and mix evenly to obtain an environmentally friendly and highly stable flux.

[0051] Implement column 3

[0052] An environmentally friendly and highly stable flux and its preparation method include the following steps:

[0053] S1. Mix 8.1g triethanolamine, 3.1g petrolatum, 5.1g cyclohexane citric acid, 0.11g rosin imidazoline, and 5.1g propylene glycol, and stir at 50℃ for 20 minutes to obtain preform a;

[0054] S2. Mix 1.1g of coumarone resin and 5.1g of hydroxyl acrylic resin, stir at 100℃ for 30min, cool to 50℃, add to preform a and stir evenly to obtain preform b.

[0055] S3. Add 1.1g vinyltriethoxysilane, 2.1g tetraethyl orthosilicate, 1.1g cholesterol, and 0.11g lecithin to 5g chloroform and stir well. Remove the chloroform by rotary evaporation. Add the mixture to a 0.01mol / L phosphate buffer solution with a pH of 6. Sonicate at 30℃ for 1h at a frequency of 15kHz. Use an extruder to pass the mixture through a 100nm filter membrane into an ammonia solution with a pH of 9. Let it stand at 50℃ for 15h, centrifuge, wash, and vacuum dry to obtain activated silica spheres.

[0056] S4. Add activated silica spheres and 0.1g dicumyl peroxide to 21g ethanol and stir evenly. Add 0.51g linolenic acid and 0.51g ethylenediamine to the mixture. Under nitrogen protection, react at 65℃ for 24h. Centrifuge, wash with water 3 times, and vacuum dry to obtain polyamide silica composite microspheres.

[0057] S5. Add 3.1g of 20nm magnesium hydroxide fiber with an aspect ratio of 20:1 and 0.5g of sodium stearate to 5g of water and stir for 1h at a stirring speed of 300r / min. Add silica composite microspheres and sonicate at 50℃ for 1h at a sonication frequency of 18kHz. Cool to room temperature, filter, wash, vacuum dry, pulverize, add 1.1g of hydrogenated castor oil and 1.1g of zinc dichloride and pre-mixed material b, and mix evenly to obtain an environmentally friendly and highly stable flux.

[0058] Implement column 4

[0059] An environmentally friendly and highly stable flux and its preparation method include the following steps:

[0060] S1. Mix 9.9g triethanolamine, 4.9g petrolatum, 7.9g cyclohexane citric acid, 0.9g rosin imidazoline, 3.9g ethyl acetate, and 3.9g ethanol, and stir at 50℃ for 20 minutes to obtain preform a;

[0061] S2. Mix 2.9g of coumarone resin and 7.9g of hydroxyl acrylic resin, stir at 100℃ for 30min, cool to 50℃, add to preform a and stir evenly to obtain preform b.

[0062] S3. Add 1.9g vinyltriethoxysilane, 5.9g tetraethyl orthosilicate, 1.9g cholesterol, and 0.49g lecithin to chloroform and stir until homogeneous. Remove the chloroform by rotary evaporation. Add the mixture to a 0.01mol / L phosphate buffer solution with a pH of 6. Sonicate at 30℃ for 1h at a frequency of 15kHz. Use an extruder to pass the mixture through a 100nm filter membrane into an ammonia solution with a pH of 9. Let it stand at 50℃ for 15h, centrifuge, wash, and vacuum dry to obtain activated silica spheres.

[0063] S4. Add activated silica spheres and 0.29g dicumyl peroxide to 39g ethanol and stir until homogeneous. Add 1.49g linolenic acid and 1.49g ethylenediamine to the mixture. Under nitrogen protection, react at 65℃ for 24h. Centrifuge, wash three times with water, and vacuum dry to obtain polyamide silica composite microspheres.

[0064] S5. Add 4.9g of 20nm magnesium hydroxide fiber with an aspect ratio of 20:1 and 1g of sodium stearate to water and stir for 1h at a stirring speed of 300r / min. Add silica composite microspheres and sonicate at 50℃ for 1h at a sonication frequency of 18kHz. Cool to room temperature, filter, wash, vacuum dry, pulverize, add 1.9g of hydrogenated castor oil and 1.9g of zinc dichloride and pre-mixed material b, and mix evenly to obtain an environmentally friendly and highly stable flux.

[0065] Example 5

[0066] An environmentally friendly and highly stable flux and its preparation method include the following steps:

[0067] S1. Mix 9g triethanolamine, 4g petrolatum, 6.5g cyclohexane citric acid, 0.5g rosin imidazoline, and 6g propylene glycol, and stir at 50℃ for 20 minutes to obtain preform a.

[0068] S2. Mix 2g of coumarone resin and 6.5g of hydroxyl acrylic resin, stir at 100℃ for 30min, cool to 50℃, add to preform a and stir evenly to obtain preform b.

[0069] S3. Add 1.5g vinyltriethoxysilane, 4g tetraethyl orthosilicate, 1.5g cholesterol, and 0.3g lecithin to 5g chloroform and stir well. Remove the chloroform by rotary evaporation. Add the mixture to a 0.01mol / L phosphate buffer solution with a pH of 6. Sonicate at 30℃ for 1h at a frequency of 15kHz. Use an extruder to pass the mixture through a 100nm filter membrane into an ammonia solution with a pH of 9. Let it stand at 50℃ for 15h, centrifuge, wash, and vacuum dry to obtain activated silica spheres.

[0070] S4. Add activated silica spheres and 0.2g dicumyl peroxide to 30g ethanol and stir evenly. Add 1g linolenic acid and 1g ethylenediamine to the mixture. Under nitrogen protection, react at 65℃ for 24h. Centrifuge, wash with water 3 times, and vacuum dry to obtain polyamide silica composite microspheres.

[0071] S5. Add 4g of 20nm magnesium hydroxide fiber with an aspect ratio of 20:1 and 0.7g of sodium stearate to 5g of water and stir for 1h at a stirring speed of 300r / min. Add silica composite microspheres and sonicate at 50℃ for 1h at a sonication frequency of 18kHz. Cool to room temperature, filter, wash, vacuum dry, pulverize, add 1.5g of hydrogenated castor oil and 1.5g of zinc dichloride and pre-mixed material b, and mix evenly to obtain an environmentally friendly and highly stable flux.

[0072] Comparative Example 1

[0073] An environmentally friendly and highly stable flux and its preparation method include the following steps:

[0074] S1. Mix 9g triethanolamine, 4g petrolatum, 6.5g cyclohexane citric acid, 0.5g rosin imidazoline, and 6g propylene glycol, and stir at 50℃ for 20 minutes to obtain preform a.

[0075] S2. Mix 2g of coumarone resin and 6.5g of hydroxyl acrylic resin, stir at 100℃ for 30min, cool to 50℃, add to preform a and stir evenly to obtain preform b.

[0076] S3. Add 1.5g vinyltriethoxysilane and 4g tetraethyl orthosilicate to 5g chloroform and stir until homogeneous. Remove the chloroform by rotary evaporation. Add the mixture to a 0.01mol / L phosphate buffer solution with a pH of 6. Sonicate at 30℃ for 1h at a frequency of 15kHz. Use an extruder to pass the mixture through a 100nm filter membrane into an ammonia solution with a pH of 9. Let it stand at 50℃ for 15h, centrifuge, wash, and vacuum dry to obtain activated silicon spheres.

[0077] S4. Add activated silica spheres and 0.2g dicumyl peroxide to 30g ethanol and stir evenly. Add 1g linolenic acid and 1g ethylenediamine to the mixture. Under nitrogen protection, react at 65℃ for 24h. Centrifuge, wash with water 3 times, and vacuum dry to obtain polyamide silica composite microspheres.

[0078] S5. Add 4g of 20nm magnesium hydroxide fiber with an aspect ratio of 20:1 and 0.7g of sodium stearate to 5g of water and stir for 1h at a stirring speed of 300r / min. Add silica composite microspheres and sonicate at 50℃ for 1h at a sonication frequency of 18kHz. Cool to room temperature, filter, wash, vacuum dry, pulverize, add 1.5g of hydrogenated castor oil, 1.5g of zinc dichloride, 1.5g of cholesterol, 0.3g of lecithin, and pre-mixed material b and mixed evenly to obtain an environmentally friendly and highly stable flux.

[0079] Comparative Example 2

[0080] An environmentally friendly and highly stable flux and its preparation method include the following steps:

[0081] S1. Mix 9g triethanolamine, 4g petrolatum, 6.5g cyclohexane citric acid, 0.5g rosin imidazoline, and 6g propylene glycol, and stir at 50℃ for 20 minutes to obtain preform a.

[0082] S2. Mix 2g of coumarone resin and 6.5g of hydroxyl acrylic resin, stir at 100℃ for 30min, cool to 50℃, add to preform a and stir evenly to obtain preform b.

[0083] S3. Add 1.5g vinyltriethoxysilane, 4g tetraethyl orthosilicate, 1.5g cholesterol, and 0.3g lecithin to 5g chloroform and stir well. Remove the chloroform by rotary evaporation. Add the mixture to a 0.01mol / L phosphate buffer solution with a pH of 6. Sonicate at 30℃ for 1h at a frequency of 15kHz. Use an extruder to pass the mixture through a 100nm filter membrane into an ammonia solution with a pH of 9. Let it stand at 50℃ for 15h, centrifuge, wash, and vacuum dry to obtain activated silica spheres.

[0084] S4. Add 4g of 20nm magnesium hydroxide fiber with an aspect ratio of 20:1 and 0.7g of sodium stearate to 5g of water and stir for 1h at a stirring speed of 300r / min. Add activated silicon balls, 0.2g of dicumyl peroxide, 30g of ethanol, 1g of linolenic acid, and 1g of ethylenediamine. Sonicate at 50℃ for 1h at a sonication frequency of 18kHz. Cool to room temperature, filter, wash, vacuum dry, pulverize, add 1.5g of hydrogenated castor oil and 1.5g of zinc dichloride, and mix evenly with pre-mixed material b to obtain an environmentally friendly and highly stable flux.

[0085] test

[0086] The environmentally friendly, highly stable fluxes prepared in Example 5 and Comparative Examples 1-2 were divided into Example 5 group and Comparative Examples 1-2 group, and the following tests were performed on each group.

[0087] Wetting performance test

[0088] A 10mm × 30mm × 0.3mm pure copper sheet was cleaned with solvent to remove oil, then immersed in a 10% hydrochloric acid solution for 5 seconds. It was then rinsed with running water, briefly immersed in anhydrous ethanol, and air-dried before being hung in a 120℃ oven for 1 hour. The wettability of the flux was tested using a Japanese SAT-5100 solderability tester. The temperature was set to 245℃, immersion depth to 4mm, immersion time to 5s, and immersion speed to 5mm / s. With the tester off, a treated pure copper sheet was clamped in a fixture. After clamping, the tester was turned on, and the automatic test button was pressed to start the measurement. The solder bath rose at a uniform speed of 5mm / s, stopping when the pure copper sheet was immersing 4mm below the molten solder surface. After a 5-second pause, it descended at the same uniform speed of 5mm / s to the starting position. The tester recorded the automatic wetting time and maximum wetting force. Each flux was tested 5 times, and the average value was taken. The test results are as follows: Figure 1-2 As shown, the wetting time of Example 5 group was the shortest and the wetting force was the greatest, both of which were better than those of Comparative Examples 1-2.

[0089] Expansion Rate Test

[0090] Solder powder and flux were mixed in a 9:1 ratio and mechanically stirred for 30 minutes to obtain solder paste. A copper-clad laminate sample sheet with dimensions of 25mm × 25mm × 1mm was prepared. After removing oil and dirt from the surface of the copper-clad laminate, it was sanded, ultrasonically cleaned in anhydrous ethanol, and dried for later use. SACBN07 solder balls of uniform mass were prepared, and their diameter was measured as D1. After reflow soldering, the height of the solder balls after spreading was measured as D2. The spread rate was calculated using the formula. The test results are as follows: Figure 3 As shown, the expansion rate of Example 5 group was the largest, which was better than that of Comparative Examples 1-2.

[0091] Formula: E = (D2 - D1) / D2 × 100%

[0092] D1: Diameter of brazing filler ball before soldering

[0093] D2: Height of the brazing filler ball after wetting and spreading on the copper plate after soldering.

[0094] Insulation test

[0095] Three Hang-type circuit boards were selected as a test sample. They were cleaned with purified water and deionized water, followed by cleaning with anhydrous ethanol or isopropanol. The test pieces were placed in an 85℃ oven for 30 minutes, then removed and cooled to room temperature. Their insulation resistance was measured, selecting a value not less than 1 x 10⁻⁶. 13 Ω specimen.

[0096] Before welding, flux was evenly applied to three Hang-shaped test pieces. The pieces were then placed in an 85℃ oven for 30 minutes, removed, and placed in a test chamber at 40℃ and 90%–95% relative humidity for 96 hours. After recovery at room temperature and 90% relative humidity for 1 hour, the insulation resistance between each point was measured using an insulation resistance tester (reading after 1 minute). The minimum value among the three test pieces was taken as the insulation resistance before welding.

[0097] The insulation resistance after welding was determined by uniformly applying flux samples to the Hang-shaped test pieces and floating them in a solder bath at 235℃ ± 5℃ for 3 seconds. Then, the pieces were placed in a test chamber at 40℃ and 90-95% relative humidity for 96 hours, followed by a 1-hour recovery period at room temperature and 90% relative humidity. The insulation resistance at each point was then measured using an insulation resistance tester (readings were taken after 1 minute). The minimum value among the three test pieces was taken as the insulation resistance after welding. The test results are as follows: Figure 4 As shown, the insulation resistance of Example 5 group was the highest, which was better than that of Comparative Examples 1-2.

[0098] Stability test

[0099] Solder powder and flux were mixed in a 9:1 ratio and mechanically stirred for 30 minutes to obtain solder paste. After preparing the solder paste, it was stirred for 2 minutes using a solder paste mixer to ensure uniformity. The viscosity was then tested using a viscometer, with the solder paste placed in the viscometer and the testing temperature set to 25°C.

[0100] After the temperature stabilized, different rotation speeds were set to observe the thixotropy and viscosity recovery of the solder paste. The measurement results were recorded. After storing at 50℃ for 30 days, the viscosity was tested using the same method to obtain the viscosity of solder pastes prepared with different fluxes before and after 30 days. The test results are as follows: Figure 5 As shown, the viscosity of Example 5 group was the highest, which was better than that of Comparative Examples 1-2.

[0101] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. An environmentally friendly and highly stable flux, characterized in that, The raw materials, by weight, include: 8-10 parts triethanolamine, 3-5 parts petrolatum, 5-8 parts cyclohexane citric acid, 0.1-1 parts corrosion inhibitor, 5-8 parts solvent, 1-3 parts coumarone resin, 5-8 parts hydroxyl acrylic resin, 1-2 parts vinyltriethoxysilane, 2-6 parts tetraethyl orthosilicate, 1-2 parts cholesterol, 0.1-0.5 parts phospholipid, 0.1-0.3 parts dicumyl peroxide, 1-3 parts polyamide monomer, 3-5 parts brucite fiber, 0.5-1.0 parts sodium stearate, 1-2 parts hydrogenated castor oil, and 1-2 parts zinc dichloride.

2. The environmentally friendly, highly stable flux according to claim 1, characterized in that, The corrosion inhibitor is rosin-aminoimidazoline.

3. The environmentally friendly, highly stable flux according to claim 1, characterized in that, The solvent is at least one of methanol, ethanol, ethyl acetate, and propylene glycol.

4. The environmentally friendly, highly stable flux according to claim 1, characterized in that, The polyamide monomers include linolenic acid and ethylenediamine, with a weight ratio of linolenic acid to ethylenediamine of 1-2:1-2.

5. The environmentally friendly, highly stable flux according to claim 1, characterized in that, The particle size of the brucite fiber is 20-30 nm, and the aspect ratio is 20-25:

1.

6. The environmentally friendly, highly stable flux according to claim 1, characterized in that, The phospholipid is lecithin.

7. A method for preparing an environmentally friendly, highly stable flux as described in any one of claims 1-6, characterized in that, Includes the following steps: S1. Mix triethanolamine, petrolatum, cyclohexane citric acid, corrosion inhibitor, and solvent, and stir at 40-50℃ for 10-20 minutes to obtain preform a; S2. Mix coumarone resin and hydroxyl acrylic resin, stir at 90-100℃ for 20-30 minutes, cool to 40-50℃, add to preform a and stir evenly to obtain preform b. S3. Add vinyltriethoxysilane, tetraethyl orthosilicate, cholesterol, and phospholipids to chloroform and stir until homogeneous. Remove chloroform by rotary evaporation and add to phosphate buffer. Sonicate at 10-30℃ for 1-2 hours. Use an extruder to pass the mixture through a 100-500nm pore size filter membrane to an ammonia solution with a pH of 8-9. Let stand at 50-60℃ for 15-30 hours, centrifuge, wash, and vacuum dry to obtain activated silicon spheres. S4. Add activated silica spheres and dicumyl peroxide to ethanol and stir evenly. Add polyamide monomer to it and react at 65-75℃ for 20-24 hours under nitrogen protection. Centrifuge, wash with water 2-3 times, and vacuum dry to obtain polyamide silica composite microspheres. S5. Add magnesium hydroxide fiber and sodium stearate to water and stir for 1-2 hours. Add silica composite microspheres and sonicate at 40-50℃ for 1-2 hours. Cool to room temperature, filter, wash, vacuum dry, pulverize, add hydrogenated castor oil and zinc dichloride, and pre-mixed material b, and mix evenly to obtain an environmentally friendly and highly stable flux.

8. The method for preparing environmentally friendly and highly stable flux according to claim 7, characterized in that, In S3, the concentration of phosphate buffer is 0.01-0.02 mol / L, and the pH is 6-6.

5.

9. The method for preparing environmentally friendly and highly stable flux according to claim 7, characterized in that, In S3, the ultrasonic frequency is 10-15kHz.

10. The method for preparing environmentally friendly and highly stable flux according to claim 7, characterized in that, In S5, the ultrasonic frequency is 12-18kHz.

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