Low-cavity easy-to-clean needle cylinder solder paste and preparation method thereof

Abstract

The invention discloses needle cylinder solder paste low in cavity and easy to clean and a preparation method of the needle cylinder solder paste. The high-temperature-resistant soldering tin powder is composed of the following components in percentage by weight: 78.0%-85.0% of soldering tin powder, 4.0%-6.0% of disproportionated rosin, 1.5%-3.0% of polyimide resin, 1.0%-2.0% of salicylic acid, 0.6%-1.2% of triethanolamine hydrochloride, 2.5%-4.0% of glycol ether, 0.8%-1.5% of organic bentonite, 0.5%-1.0% of gas-phase aluminum oxide, 0.2%-0.4% of tert-butylhydroquinone, 0.3%-0.6% of Tween 80, 0.4%-0.8% of polyvinyl alcohol and 0.15%-0.35% of mercaptobenzothiazole. 0.1 to 0.25 percent of sodium citrate and 0.05 to 0.15 percent of lauryl sodium sulfate; according to the needle cylinder solder paste, through reasonable formula design and a preparation process, the dispensing performance, the storage stability, the welding quality, the cleaning performance and the like of the needle cylinder solder paste are remarkably improved. And the soldering tin powder and the soldering flux act synergistically, so that stable tin discharge of continuous spot coating is ensured, and the hole blocking rate is greatly reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of soldering materials for electronic manufacturing, in particular to a low-cavity and easy-to-clean needle cylinder solder paste and a preparation method thereof. BACKGROUND

[0002] In the surface mounting technology of electronic manufacturing, the needle cylinder solder paste is one of the key materials, and its performance directly affects the welding quality and production efficiency. The existing needle cylinder solder paste has many problems: unstable soldering during dotting, easy to appear broken soldering, multiple soldering phenomenon, high hole blocking rate, affecting continuous production; prone to oxidation, delamination during storage, large viscosity change, poor storage stability; high cavity rate after welding, reducing the mechanical strength and conductivity of the welding point; and the residue of part of the soldering flux is difficult to clean, affecting the subsequent use of electronic components. Therefore, it is of great significance to develop a high-stability dotting needle cylinder solder paste which is stable in dotting, good in storage, high in welding quality and easy to clean. SUMMARY

[0003] In view of the deficiencies of the prior art, the present application provides a low-cavity and easy-to-clean needle cylinder solder paste and a preparation method thereof, which solves the problems raised in the background art.

[0004] To achieve the above purpose, the present application is realized by the following technical scheme: a low-cavity and easy-to-clean needle cylinder solder paste, which is composed of the following components in weight percentage:

[0005] soldering powder 78.0-85.0%, disproportionated rosin 4.0-6.0%, polyimide resin 1.5-3.0%, salicylic acid 1.0-2.0%, triethanolamine hydrochloride 0.6-1.2%, ethylene glycol ether 2.5-4.0%, organic bentonite 0.8-1.5%, fumed alumina 0.5-1.0%, tert-butyl hydroquinone 0.2-0.4%, Tween 80 0.3-0.6%, polyvinyl alcohol 0.4-0.8%, mercaptobenzothiazole 0.15-0.35%, sodium citrate 0.1-0.25%, and sodium dodecyl sulfate 0.05-0.15%.

[0006] Preferably, it is composed of the following components in weight percentage:

[0007] soldering powder 82.0%, disproportionated rosin 5.0%, polyimide resin 2.2%, salicylic acid 1.5%, triethanolamine hydrochloride 0.9%, ethylene glycol ether 3.2%, organic bentonite 1.2%, fumed alumina 0.7%, tert-butyl hydroquinone 0.3%, Tween 80 0.45%, polyvinyl alcohol 0.6%, mercaptobenzothiazole 0.25%, sodium citrate 0.18%, and sodium dodecyl sulfate 0.12%.

[0008] Preferably, it is composed of the following components in weight percentage:

[0009] Solder powder 78.0%, disproportionated rosin 6.0%, polyimide resin 3.0%, salicylic acid 2.0%, triethanolamine hydrochloride 1.2%, ethylene glycol ethyl ether 4.0%, organic bentonite 1.5%, fumed alumina 1.0%, t-butyl hydroquinone 0.4%, Tween 80 0.6%, polyvinyl alcohol 0.8%, mercaptobenzothiazole 0.35%, sodium citrate 0.25%, and sodium dodecyl sulfate 0.15%.

[0010] Preferably, consisting of the following ingredients by weight percentage:

[0011] Solder powder 85.0%, disproportionated rosin 4.0%, polyimide resin 1.5%, salicylic acid 1.0%, triethanolamine hydrochloride 0.6%, ethylene glycol ethyl ether 2.5%, organic bentonite 0.8%, fumed alumina 0.5%, t-butyl hydroquinone 0.2%, Tween 80 0.3%, polyvinyl alcohol 0.4%, mercaptobenzothiazole 0.15%, sodium citrate 0.1%, and sodium dodecyl sulfate 0.05%.

[0012] The role of each component in the raw material is as follows:

[0013] Solder powder: provides the metal matrix required for soldering, ensuring the mechanical strength and electrical conductivity of the solder joints, composed of tin, lead, and silver in specific proportions, with appropriate melting point and fluidity.

[0014] Disproportionated rosin: as the main flux, it has excellent wettability and thermal stability, can effectively remove the oxide layer on the metal surface, and promote the spread of solder.

[0015] Polyimide resin: enhances the adhesion strength and high-temperature resistance of the solder paste, improves the anti-aging and impact resistance of the solder joints.

[0016] Salicylic acid: as an organic acid activator, it helps remove the oxide film on the metal surface, enhances soldering activity, and the residue is easy to clean.

[0017] Triethanolamine hydrochloride: an organic amine salt activator that enhances the fluxing effect, especially for various metal substrates.

[0018] Ethylene glycol ethyl ether: an environmentally friendly solvent that adjusts the viscosity of the solder paste, ensures smoothness during spot coating, and promotes the compatibility of the components, and is easy to evaporate for subsequent cleaning.

[0019] Organic bentonite: a thixotropic agent that gives the solder paste good thixotropy, good flowability during spot coating, shape stability when standing still, and reduces collapse and sagging.

[0020] Gas phase alumina: synergistic effect with thixotropic agent, further optimize the rheological properties of tin paste, improve the stability of continuous point coating, while enhancing the hardness of the solder joints.

[0021] Tert-butyl hydroquinone: antioxidant, inhibit the oxidation of tin paste during storage and use, prolong the shelf life.

[0022] Tween 80: non-ionic surfactant, reduce the interfacial tension, improve the compatibility of solder powder and flux, reduce agglomeration, and help improve the cleaning properties.

[0023] Polyvinyl alcohol: thickening agent, adjust the viscosity of the tin paste, prevent the solder powder from settling, improve the stability of the system.

[0024] Mercaptobenzothiazole: metal passivator, forms a protective film on the metal surface, prevents subsequent corrosion of the solder joints, and improves the long-term reliability of the solder joints.

[0025] Sodium citrate: metal chelating agent, forms stable chelates with metal ions, prevents metal ions from catalyzing oxidation reactions, and enhances storage stability.

[0026] Sodium dodecyl sulfate: anionic surfactant, enhances the penetration ability of the flux, improves the soldering effect, and helps clean the residual flux.

[0027] Preferably, the solder powder is composed of tin, lead, and silver in a mass ratio of 90:8:2, has a particle size of 15-30 microns, and is prepared by centrifugal atomization; the disproportionated rosin has an acid value of 140-160 mgKOH / g and a softening point of 80-90°C; the polyimide resin has a molecular weight of 4000-6000 and a glass transition temperature of 200-250°C.

[0028] A method for preparing a low-cavity easy-to-clean needle cylinder tin paste, comprising the following steps:

[0029] Step 1, solder powder preparation: tin, lead, and silver are added to a vacuum melting furnace in a mass ratio of 90:8:2, and are melted and mixed at 300-350°C under inert gas protection for 40-50 minutes to form an alloy melt; the melt is atomized into powder by centrifugal atomization at a rotation speed of 8000-10000 rpm, and the solder powder with a particle size of 15-30 microns is screened out after cooling for standby; the inert gas is helium or neon, and the cooling medium for centrifugal atomization is cooling oil;

[0030] Step 2, Raw material pretreatment: Dry disproportionated rosin and polyimide resin separately in a vacuum drying oven at 70-80℃ for 3-4 hours; grind salicylic acid, triethanolamine hydrochloride, tert-butylhydroquinone, mercaptobenzothiazole, and sodium citrate to a 120-150 mesh sieve; preheat organic bentonite, fumed alumina, and polyvinyl alcohol in an oven at 60-65℃ for 1-2 hours;

[0031] Step 3, Flux Preparation: Add ethylene glycol ethyl ether to the reactor, heat to 50-60℃, stir at 300-400 rpm, and add disproportionated rosin and polyimide resin sequentially until completely dissolved; add salicylic acid and triethanolamine hydrochloride, and stir for 20-25 minutes; add organobentonite and fumed alumina, heat to 70-75℃, and stir for 40-50 minutes; add tert-butylhydroquinone, Tween 80, polyvinyl alcohol, mercaptobenzothiazole, sodium citrate, and sodium dodecyl sulfate, and stir for 35-45 minutes to obtain the flux; the agitator of the reactor is a ribbon agitator.

[0032] Step 4, Mixing: Add the solder powder from Step 1 and the flux from Step 3 to a twin-screw mixer at a mass ratio of 82:18, and stir for 20-25 minutes at 800-1000 rpm under helium protection.

[0033] Step 5, Grinding and Dispersing: Transfer the mixture to a three-roll mill, adjust the roller gap to 5-10 micrometers, and grind at 150-200 rpm for 30-40 minutes to evenly disperse the solder powder;

[0034] Step 6, Degassing treatment: Degas the ground material under vacuum conditions of -0.1 to -0.09 MPa and 40-45℃ for 25-30 minutes;

[0035] Step 7, Aging treatment: Aging the degassed material in a constant temperature chamber at 30-35℃ for 36-60 hours. Stir once every 12 hours during the aging process, with a stirring speed of 200-250 rpm and a stirring time of 8 minutes.

[0036] Step 8, Sieving and Filtration: Use a 150-200 mesh sieve to remove impurities and large particles;

[0037] Step 9, Filling: In a Class 500 cleanroom environment, fill the syringe with a pressure of 0.3-0.4 MPa;

[0038] Step 10, Packaging: Vacuum-packed in aluminum foil bags and stored at 2-8℃.

[0039] Preferably, in step 3, the reactor is kept under vacuum of -0.06 to -0.04 MPa during stirring to ensure that the flux components are evenly dispersed.

[0040] Preferably, in step 7, the viscosity change rate of the solder paste after 30 days of storage following chemical treatment is ≤5%, and the uniformity of solder powder dispersion is ≥98%.

[0041] Preferably, in step 9, the filled syringe solder paste has a blockage rate of ≤1%, a solder joint void rate of ≤5%, and a bonding strength of ≥35MPa during spot application.

[0042] Preferably, the cooling medium for centrifugal atomization in step 1 is cooling oil, and the total stirring time for flux preparation in step 3 is 120-150 minutes to ensure that all components react fully.

[0043] Compared with the prior art, the present invention has the following advantages:

[0044] This invention, through rational formulation design and preparation process, significantly improves the dispensing performance, storage stability, soldering quality, and cleanability of syringe solder paste. The synergistic effect of solder powder and flux ensures stable continuous dispensing and a substantial reduction in pore blockage. The addition of various additives effectively inhibits oxidation and delamination, improving storage stability. Post-soldering, the paste exhibits low void ratio, good solder joint strength and conductivity, and easy-to-clean flux residue, providing a superior material choice for high-density electronic assembly. Attached Figure Description

[0045] Figure 1 This is a flowchart of the preparation method of the present invention. Detailed Implementation

[0046] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0047] Please see Figure 1 This invention provides a technical solution: a low-void, easy-to-clean syringe solder paste, composed of the following components by weight percentage:

[0048] The composition includes: solder powder 78.0-85.0%, disproportionated rosin 4.0-6.0%, polyimide resin 1.5-3.0%, salicylic acid 1.0-2.0%, triethanolamine hydrochloride 0.6-1.2%, ethylene glycol ethyl ether 2.5-4.0%, organobentonite 0.8-1.5%, fumed alumina 0.5-1.0%, tert-butylhydroquinone 0.2-0.4%, Tween 80 0.3-0.6%, polyvinyl alcohol 0.4-0.8%, mercaptobenzothiazole 0.15-0.35%, sodium citrate 0.1-0.25%, and sodium dodecyl sulfate 0.05-0.15%.

[0049] The functions of each component in the raw material are as follows:

[0050] Solder powder: provides the metal matrix required for welding, ensuring the mechanical strength and conductivity of the solder joint. It is composed of tin, lead and silver in a specific ratio and has a suitable melting point and fluidity.

[0051] Disproportionated rosin: As the main flux component, it has excellent wettability and thermal stability, effectively removes the oxide layer on the metal surface, and promotes solder spreading.

[0052] Polyimide resin: enhances the bonding strength and high-temperature resistance of solder paste, and improves the aging resistance and impact resistance of solder joints.

[0053] Salicylic acid: As an organic acid surfactant, it helps remove oxide films from metal surfaces, improves welding activity, and leaves residues that are easy to clean.

[0054] Triethanolamine hydrochloride: An organic amine salt activator that enhances soldering performance, especially effective on various metal substrates.

[0055] Ethylene glycol ethyl ether: an environmentally friendly solvent that adjusts the viscosity of solder paste, ensuring smooth application, promoting compatibility of components, and is volatile for easy cleaning later.

[0056] Organic bentonite: a thixotropic agent that imparts good thixotropic properties to solder paste, allowing it to flow well during application and maintain its shape when left to stand, thus reducing collapse and sagging.

[0057] Fumed alumina: works synergistically with thixotropic agents to further optimize the rheological properties of solder paste, improve the stability of continuous spot coating, and enhance the hardness of solder joints.

[0058] tert-Butylhydroquinone: An antioxidant that inhibits oxidation and deterioration of solder paste during storage and use, extending its shelf life.

[0059] Tween 80: A nonionic surfactant that reduces interfacial tension, improves the compatibility of solder powder and flux, reduces agglomeration, and helps improve cleanability.

[0060] Polyvinyl alcohol: a thickener that adjusts the viscosity of solder paste, prevents solder powder from settling, and improves system stability.

[0061] Mercaptobenzothiazole: a metal passivating agent that forms a protective film on the metal surface to prevent subsequent corrosion of the weld joint and improve the long-term reliability of the welded joint.

[0062] Sodium citrate: A metal chelating agent that forms stable chelates with metal ions, preventing metal ions from catalyzing oxidation reactions and enhancing storage stability.

[0063] Sodium dodecyl sulfate: An anionic surfactant that enhances the penetration of flux, improves welding results, and also helps in cleaning flux residues.

[0064] The solder powder is composed of tin, lead, and silver in a mass ratio of 90:8:2, with a particle size of 15-30 micrometers, and is prepared by centrifugal atomization. The disproportionated rosin has an acid value of 140-160 mgKOH / g and a softening point of 80-90℃. The polyimide resin has a molecular weight of 4000-6000 and a glass transition temperature of 200-250℃.

[0065] A method for preparing a low-void, easy-to-clean syringe solder paste includes the following steps:

[0066] Step 1: Solder powder preparation: Tin, lead, and silver are added to a vacuum melting furnace at a mass ratio of 90:8:2. Under inert gas protection, they are melted and mixed at 300-350℃ for 40-50 minutes to form an alloy melt. The melt is then atomized into powder using centrifugal atomization at a speed of 8000-10000 rpm. After cooling, solder powder with a particle size of 15-30 micrometers is screened out for later use. The inert gas is helium or neon, and the cooling medium for centrifugal atomization is cooling oil.

[0067] Step 2, Raw material pretreatment: Dry disproportionated rosin and polyimide resin separately in a vacuum drying oven at 70-80℃ for 3-4 hours; grind salicylic acid, triethanolamine hydrochloride, tert-butylhydroquinone, mercaptobenzothiazole, and sodium citrate to a 120-150 mesh sieve; preheat organic bentonite, fumed alumina, and polyvinyl alcohol in an oven at 60-65℃ for 1-2 hours;

[0068] Step 3, Flux Preparation: Add ethylene glycol ethyl ether to the reactor, heat to 50-60℃, stir at 300-400 rpm, and add disproportionated rosin and polyimide resin sequentially until completely dissolved; add salicylic acid and triethanolamine hydrochloride, and stir for 20-25 minutes; add organobentonite and fumed alumina, heat to 70-75℃, and stir for 40-50 minutes; add tert-butylhydroquinone, Tween 80, polyvinyl alcohol, mercaptobenzothiazole, sodium citrate, and sodium dodecyl sulfate, and stir for 35-45 minutes to obtain the flux; the stirring paddle in the reactor is a ribbon-type stirring paddle; the reactor is kept under vacuum of -0.06 to -0.04 MPa during stirring to ensure uniform dispersion of the flux components; the total stirring time for flux preparation is 120-150 minutes;

[0069] Step 4, Mixing: Add the solder powder from Step 1 and the flux from Step 3 to a twin-screw mixer at a mass ratio of 82:18, and stir for 20-25 minutes at 800-1000 rpm under helium protection.

[0070] Step 5, Grinding and Dispersing: Transfer the mixture to a three-roll mill, adjust the roller gap to 5-10 micrometers, and grind at 150-200 rpm for 30-40 minutes to evenly disperse the solder powder;

[0071] Step 6, Degassing treatment: Degas the ground material under vacuum conditions of -0.1 to -0.09 MPa and 40-45℃ for 25-30 minutes;

[0072] Step 7, Aging treatment: The degassed material is aged in a constant temperature chamber at 30-35℃ for 36-60 hours. During the aging process, it is stirred once every 12 hours at a stirring speed of 200-250 rpm for 8 minutes. After 30 days of storage after aging treatment, the viscosity change rate of the solder paste is ≤5%, and the uniformity of solder powder dispersion is ≥98%.

[0073] Step 8, Sieving and Filtration: Use a 150-200 mesh sieve to remove impurities and large particles;

[0074] Step 9, Filling: In a Class 500 cleanroom environment, fill the syringe with 0.3-0.4 MPa pressure; the filled syringe solder paste should have a pore blockage rate of ≤1%, a solder joint void rate of ≤5%, and a bonding strength of ≥35 MPa when applied.

[0075] Step 10, Packaging: Vacuum-packed in aluminum foil bags and stored at 2-8℃.

[0076] Example 1:

[0077] Formula composition (by weight):

[0078] The composition includes 82.0% solder powder, 5.0% disproportionated rosin, 2.2% polyimide resin, 1.5% salicylic acid, 0.9% triethanolamine hydrochloride, 3.2% ethylene glycol ethyl ether, 1.2% organobentonite, 0.7% fumed alumina, 0.3% tert-butylhydroquinone, 0.45% Tween 80, 0.6% polyvinyl alcohol, 0.25% mercaptobenzothiazole, 0.18% sodium citrate, and 0.12% sodium dodecyl sulfate.

[0079] Preparation method:

[0080] Step 1: In the preparation of solder powder, the melting temperature is 320℃, the atomization speed is 9000 rpm, and the powder with a particle size of 20-25 micrometers is screened.

[0081] Step 3: When preparing the flux, heat the ethylene glycol ethyl ether to 55°C, stir at 350 rpm, add the components, and operate according to the above time and temperature parameters.

[0082] Step 4: Mix at 900 rpm using a twin-screw mixer for 22 minutes.

[0083] Step 5: Grind for 35 minutes at a three-roll mill with a roller spacing of 8 micrometers and a rotation speed of 180 rpm.

[0084] Step 6: Vacuum degassing, vacuum degree -0.095MPa, temperature 42℃, time 28 minutes.

[0085] Step 7: Aging temperature 32℃, time 48 hours.

[0086] Example 2:

[0087] Formula composition (by weight):

[0088] The composition includes 78.0% solder powder, 6.0% disproportionated rosin, 3.0% polyimide resin, 2.0% salicylic acid, 1.2% triethanolamine hydrochloride, 4.0% ethylene glycol ethyl ether, 1.5% organobentonite, 1.0% fumed alumina, 0.4% tert-butylhydroquinone, 0.6% Tween 80, 0.8% polyvinyl alcohol, 0.35% mercaptobenzothiazole, 0.25% sodium citrate, and 0.15% sodium dodecyl sulfate.

[0089] Preparation method:

[0090] Step 1: Melting temperature 300℃, atomization speed 8000 rpm, screening powder with a particle size of 15-20 micrometers.

[0091] Step 3: Heat the ethylene glycol ethyl ether to 50°C and stir at 300 rpm.

[0092] Step 4: Mix at 800 rpm for 25 minutes.

[0093] Step 5: Grind the rollers of the grinder with a gap of 5 micrometers, rotate at 150 rpm, and grind for 40 minutes.

[0094] Step 6: Degassing vacuum degree -0.1MPa, temperature 40℃, time 30 minutes.

[0095] Step 7: Aging temperature 30℃, time 60 hours.

[0096] Example 3:

[0097] Formula composition (by weight):

[0098] The composition includes 85.0% solder powder, 4.0% disproportionated rosin, 1.5% polyimide resin, 1.0% salicylic acid, 0.6% triethanolamine hydrochloride, 2.5% ethylene glycol ethyl ether, 0.8% organobentonite, 0.5% fumed alumina, 0.2% tert-butylhydroquinone, 0.3% Tween 80, 0.4% polyvinyl alcohol, 0.15% mercaptobenzothiazole, 0.1% sodium citrate, and 0.05% sodium dodecyl sulfate.

[0099] Preparation method:

[0100] Step 1: Melting temperature 350℃, atomization speed 10000 rpm, screening powder with a particle size of 25-30 micrometers.

[0101] Step 3: Heat the ethylene glycol ethyl ether to 60°C and stir at 400 rpm.

[0102] Step 4: Mix at 1000 rpm for 20 minutes.

[0103] Step 5: Grind the rollers of the grinder with a spacing of 10 micrometers, a rotation speed of 200 rpm, and grind for 30 minutes.

[0104] Step 6: Degassing vacuum degree -0.09MPa, temperature 45℃, time 25 minutes.

[0105] Step 7: Aging temperature 35℃, time 36 hours.

[0106] The following table compares Embodiments 1-3 of the present invention with the prior art:

[0107]

[0108]

[0109] This invention, through rational formulation design and preparation process, significantly improves the dispensing performance, storage stability, soldering quality, and cleanability of syringe solder paste. The synergistic effect of solder powder and flux ensures stable continuous dispensing and a substantial reduction in pore blockage. The addition of various additives effectively inhibits oxidation and delamination, improving storage stability. Post-soldering, the paste exhibits low void ratio, good solder joint strength and conductivity, and easy-to-clean flux residue, providing a superior material choice for high-density electronic assembly.

[0110] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A low-void, easy-to-clean syringe solder paste, characterized in that, It consists of the following components by weight percentage: The composition includes: solder powder 78.0-85.0%, disproportionated rosin 4.0-6.0%, polyimide resin 1.5-3.0%, salicylic acid 1.0-2.0%, triethanolamine hydrochloride 0.6-1.2%, ethylene glycol ethyl ether 2.5-4.0%, organobentonite 0.8-1.5%, fumed alumina 0.5-1.0%, tert-butylhydroquinone 0.2-0.4%, Tween 80 0.3-0.6%, polyvinyl alcohol 0.4-0.8%, mercaptobenzothiazole 0.15-0.35%, sodium citrate 0.1-0.25%, and sodium dodecyl sulfate 0.05-0.15%.

2. The low-void, easy-to-clean syringe solder paste according to claim 1, characterized in that, It consists of the following components by weight percentage: The composition includes 82.0% solder powder, 5.0% disproportionated rosin, 2.2% polyimide resin, 1.5% salicylic acid, 0.9% triethanolamine hydrochloride, 3.2% ethylene glycol ethyl ether, 1.2% organobentonite, 0.7% fumed alumina, 0.3% tert-butylhydroquinone, 0.45% Tween 80, 0.6% polyvinyl alcohol, 0.25% mercaptobenzothiazole, 0.18% sodium citrate, and 0.12% sodium dodecyl sulfate.

3. The low-void, easy-to-clean syringe solder paste according to claim 1, characterized in that, It consists of the following components by weight percentage: The composition includes 78.0% solder powder, 6.0% disproportionated rosin, 3.0% polyimide resin, 2.0% salicylic acid, 1.2% triethanolamine hydrochloride, 4.0% ethylene glycol ethyl ether, 1.5% organobentonite, 1.0% fumed alumina, 0.4% tert-butylhydroquinone, 0.6% Tween 80, 0.8% polyvinyl alcohol, 0.35% mercaptobenzothiazole, 0.25% sodium citrate, and 0.15% sodium dodecyl sulfate.

4. The low-void, easy-to-clean syringe solder paste according to claim 1, characterized in that, It consists of the following components by weight percentage: The composition includes 85.0% solder powder, 4.0% disproportionated rosin, 1.5% polyimide resin, 1.0% salicylic acid, 0.6% triethanolamine hydrochloride, 2.5% ethylene glycol ethyl ether, 0.8% organobentonite, 0.5% fumed alumina, 0.2% tert-butylhydroquinone, 0.3% Tween 80, 0.4% polyvinyl alcohol, 0.15% mercaptobenzothiazole, 0.1% sodium citrate, and 0.05% sodium dodecyl sulfate.

5. A low-void, easy-to-clean syringe solder paste according to any one of claims 1-4, characterized in that, The solder powder is composed of tin, lead, and silver in a mass ratio of 90:8:2, with a particle size of 15-30 micrometers, and is prepared by centrifugal atomization. The disproportionated rosin has an acid value of 140-160 mgKOH / g and a softening point of 80-90℃. The polyimide resin has a molecular weight of 4000-6000 and a glass transition temperature of 200-250℃.

6. A method for preparing a low-void, easily cleanable syringe solder paste according to any one of claims 1-5, characterized in that, Includes the following steps: Step 1, Solder powder preparation: Add tin, lead and silver in a mass ratio of 90:8:2 into a vacuum melting furnace, and melt and mix them at 300-350℃ for 40-50 minutes under inert gas protection to form an alloy melt; The melt is atomized into powder using centrifugal atomization at a speed of 8000-10000 rpm. After cooling, solder powder with a particle size of 15-30 micrometers is screened out for later use. The inert gas is helium or neon. Step 2, Raw material pretreatment: Dry disproportionated rosin and polyimide resin separately in a vacuum drying oven at 70-80℃ for 3-4 hours; grind salicylic acid, triethanolamine hydrochloride, tert-butylhydroquinone, mercaptobenzothiazole, and sodium citrate to a 120-150 mesh sieve; preheat organic bentonite, fumed alumina, and polyvinyl alcohol in an oven at 60-65℃ for 1-2 hours; Step 3, Flux Preparation: Add ethylene glycol ethyl ether to the reactor, heat to 50-60℃, stir at 300-400 rpm, and add disproportionated rosin and polyimide resin sequentially until completely dissolved; add salicylic acid and triethanolamine hydrochloride, and stir for 20-25 minutes; add organobentonite and fumed alumina, heat to 70-75℃, and stir for 40-50 minutes; add tert-butylhydroquinone, Tween 80, polyvinyl alcohol, mercaptobenzothiazole, sodium citrate, and sodium dodecyl sulfate, and stir for 35-45 minutes to obtain the flux; the agitator of the reactor is a ribbon agitator. Step 4, Mixing: Add the solder powder from Step 1 and the flux from Step 3 to a twin-screw mixer at a mass ratio of 82:18, and stir for 20-25 minutes at 800-1000 rpm under helium protection. Step 5, Grinding and Dispersing: Transfer the mixture to a three-roll mill, adjust the roller gap to 5-10 micrometers, and grind at 150-200 rpm for 30-40 minutes to evenly disperse the solder powder; Step 6, Degassing treatment: Degas the ground material under vacuum conditions of -0.1 to -0.09 MPa and 40-45℃ for 25-30 minutes; Step 7, Aging treatment: Aging the degassed material in a constant temperature chamber at 30-35℃ for 36-60 hours. Stir once every 12 hours during the aging process, with a stirring speed of 200-250 rpm and a stirring time of 8 minutes. Step 8, Sieving and Filtration: Use a 150-200 mesh sieve to remove impurities and large particles; Step 9, Filling: In a Class 500 cleanroom environment, fill the syringe with a pressure of 0.3-0.4 MPa; Step 10, Packaging: Vacuum-packed in aluminum foil bags and stored at 2-8℃.

7. The method for preparing a low-void, easily cleanable syringe solder paste according to claim 6, characterized in that, In step 3, the reactor is kept under vacuum of -0.06 to -0.04 MPa during stirring to ensure that the flux components are evenly dispersed.

8. The method for preparing a low-void, easily cleanable syringe solder paste according to claim 6, characterized in that, In step 7, the viscosity change rate of the solder paste after 30 days of storage following chemical treatment is ≤5%, and the uniformity of solder powder dispersion is ≥98%.

9. The method for preparing a low-void, easily cleanable syringe solder paste according to claim 6, characterized in that, In step 9, the filled syringe solder paste has a blockage rate of ≤1%, a solder joint void rate of ≤5%, and a bonding strength of ≥35MPa during spot application.

10. The method for preparing a low-void, easily cleanable syringe solder paste according to claim 6, characterized in that, In step 1, the cooling medium for centrifugal atomization is cooling oil, and in step 3, the total stirring time for flux preparation is 120-150 minutes to ensure that all components react fully.

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