Automobile electronic connector through hole printing soldering paste and preparation method thereof

Abstract

The invention relates to the technical field of soldering paste, in particular to automotive electronic connector through hole printing soldering paste and a preparation method thereof, and particularly discloses automotive electronic connector through hole printing soldering paste which comprises the following components in percentage by mass: 88-92% of metal powder and the balance of auxiliaries, the metal powder comprises, by mass, 98-99% of welding alloy powder and the balance skeleton alloy powder, the welding alloy powder is tin-copper alloy powder, and the skeleton alloy powder is silver-copper-titanium alloy powder; the auxiliary agent is prepared from the following components in percentage by mass: 5 to 8 percent of hydrogenated rosin methyl ester, 2 to 6 percent of hydrogenated rosin pentaerythritol ester, 3 to 8 percent of ethanolamine and the balance of trimethyl pentanediol. The method has the advantage of high welding spot strength.

Description

Technical Field

[0001] This invention relates to the technical field of solder paste, and in particular to a through-hole printing solder paste for automotive electronic connectors and its preparation method. Background Technology

[0002] As the automotive industry rapidly iterates towards electrification, intelligence, and connectivity, the complexity and integration of automotive electronic systems continue to increase, leading to an explosive growth in the use of automotive electronics. Automotive electronics have become the core carrier determining vehicle performance, safety, and user experience. Solder paste, as the core interconnecting material that enables mechanical fixation, electrical connection, and heat conduction between automotive electronic components (chips, sensors, connectors, etc.) and printed circuit boards (PCBs), directly determines the reliability, stability, and lifespan of automotive electronic systems. It is one of the key basic materials for the high-quality development of the automotive electronics industry.

[0003] Traditional solder paste used in automotive electronic connectors often suffers from poor alloy strength, weak fluxing force in forming the solder joint alloy layer, thin solder joints, and poor solder joint strength. In particular, solder joints with insufficient welding strength are prone to cracking or loose connections after long-term vibration or bumps, leading to automotive electronic malfunctions, affecting vehicle safety, and causing traffic accidents or personal injury. Summary of the Invention

[0004] To improve solder joint strength, this invention addresses the problems of existing technologies by providing a through-hole printed solder paste for automotive electronic connectors and its preparation method.

[0005] In a first aspect, this application provides a through-hole printed solder paste for automotive electronic connectors, employing the following technical solution:

[0006] The present invention provides a through-hole printed solder paste for automotive electronic connectors, which adopts the following technical solution:

[0007] A through-hole printed solder paste for automotive electronic connectors, comprising, by weight percentage, the following components: 88-92% metal powder, with the balance being additives. The metal powder comprises 98-99% by weight of solder alloy powder and the balance of skeleton alloy powder. The solder alloy powder is a tin-copper alloy powder, and the skeleton alloy powder is a silver-copper-titanium alloy powder. The additives comprise 5-8% by weight of hydrogenated rosin methyl ester, 2-6% by weight of hydrogenated rosin pentaerythritol ester, 3-8% by weight of ethanolamine, with the balance being trimethylpentanediol.

[0008] Preferably, the solder paste comprises the following components by mass percentage: 90% metal powder, with the balance being additives, wherein the metal powder comprises 98.75% solder alloy powder and 1.25% skeleton alloy powder by mass, the solder alloy powder being tin-copper alloy powder and the skeleton alloy powder being silver-copper-titanium alloy powder; the additives comprise 7% hydrogenated rosin methyl ester, 4% hydrogenated rosin pentaerythritol ester, 5% ethanolamine, and the balance being trimethylpentanediol.

[0009] Preferably, the tin content in the welding alloy powder is 98.05% by mass of the metal powder, and the copper content in the welding alloy powder is 0.7% by mass of the metal powder; the silver content in the skeleton alloy powder is 0.75% by mass of the metal powder, the copper content in the skeleton alloy powder is 0.35% by mass of the metal powder, and the titanium content in the skeleton alloy powder is 0.15% by mass of the metal powder.

[0010] Preferably, the particle size range of the welding alloy powder is 25-45 μm, and the particle size range of the skeleton alloy powder is 35-45 μm.

[0011] Preferred, preferred

[0012] Secondly, this application provides a method for preparing through-hole printed solder paste for automotive electronic connectors, employing the following technical solution:

[0013] A method for preparing through-hole solder paste for automotive electronic connectors includes the following steps:

[0014] S1: Melt the copper-tin alloy at 350-370℃ and stir for 25-35 minutes, then atomize it by centrifugation to obtain welding alloy powder;

[0015] S2: Heat the silver-copper-titanium alloy to 890-910℃ to melt and stir for 4-6 minutes, then cast and cool it into a silver-copper-titanium alloy block. Then, the silver-copper-titanium alloy block is ball-milled to obtain skeleton alloy powder.

[0016] S3: Place the welding alloy powder and the skeleton alloy powder into the granulator, and add isopropanol of the same mass as the welding alloy powder and the skeleton alloy powder. The stirring speed of the granulator is 25-35 rpm, and the granulation time is 1-2 hours. After granulation, turn on the granulator and heat it to 80-90℃ to dry it completely to obtain metal powder.

[0017] S4: An auxiliary agent is obtained by mixing hydrogenated rosin methyl ester, hydrogenated rosin pentaerythritol ester, ethanolamine, and trimethylpentanediol;

[0018] S5: Mix the metal powder with the additives and add them to a star mixer. Stir at 50-60 rpm and keep at room temperature for 1-2 hours to obtain solder paste.

[0019] Preferably, in step S1, the tin content in the welding alloy powder accounts for 98.05% of the mass percentage of the metal powder, and the copper content in the welding alloy powder accounts for 0.7% of the mass percentage of the metal powder; in step S3, the silver content in the skeleton alloy powder accounts for 0.75% of the mass percentage of the metal powder, the copper content in the skeleton alloy powder accounts for 0.35% of the mass percentage of the metal powder, and the titanium content in the skeleton alloy powder accounts for 0.15% of the mass percentage of the metal powder.

[0020] Preferably, in step S5, the additive contains 5-8% by mass of hydrogenated rosin methyl ester, 2-6% by mass of hydrogenated rosin pentaerythritol ester, 3-8% by mass of ethanolamine, and the balance being trimethylpentanediol.

[0021] Preferably, in step S4, the solder paste contains 88-92% metal powder by mass, with the remainder being additives.

[0022] Preferably, the particle size range of the welding alloy powder is 25-45 μm, and the particle size range of the skeleton alloy powder is 35-45 μm.

[0023] In summary, the present invention has at least one of the following beneficial technical effects:

[0024] Adding silver-copper-titanium alloy powder to solder paste greatly improves the structural strength of solder joints, making it less prone to cracks and poor connections between the PCB and connectors. Detailed Implementation

[0025] As used herein, the terms “consisting of,” “including,” “comprising,” “having,” “having,” or any other variation thereof are intended to cover the meaning of non-exclusive inclusion. For example, a process, method, article, or apparatus that includes a list of features is not necessarily limited to the respective features, but may include other features not expressly listed or inherent to such a process, method, article, or apparatus.

[0026] As used herein, unless otherwise expressly stated, "or" means inclusive "or" rather than exclusive "or". For example, any of the following can satisfy condition A or B: A is true (or exists) and B is false (or does not exist), A is false (or does not exist) and B is true (or exists), and both A and B are true (or exist). The present application will be further described in detail below with reference to embodiments.

[0027] The present application will be further described in detail below with reference to the embodiments.

[0028] Example

[0029] Example 1

[0030] A type of through-hole printed solder paste for automotive electronic connectors is prepared according to the following steps:

[0031] S1: 1000g of copper-tin alloy is heated to 350℃ to melt and stirred for 25 minutes. Then, it is centrifuged and atomized to obtain welding alloy powder. The mass of tin in the copper-tin alloy is 993g, the mass of copper is 7g, and the particle size of the welding alloy powder is 25μm.

[0032] S2: Heat 1000g of silver-copper-titanium alloy to 890℃ to melt and stir for 4 minutes, then cast and cool it into a silver-copper-titanium alloy block. Then, the silver-copper-titanium alloy block is ball-milled to obtain skeleton alloy powder. The mass of silver in the silver-copper-titanium alloy is 600g, the mass of copper is 280g, the mass of titanium is 120g, and the particle size of the skeleton alloy powder is 35μm.

[0033] S3: Place 980g of welding alloy powder and 20g of skeleton alloy powder into a granulator, add 1000g of isopropanol, the granulator stirring speed is 25 rpm, the granulation time is 1 hour, after granulation is completed, turn on the granulator and heat to 80℃ to dry completely to obtain metal powder.

[0034] S4: Mix 5g of hydrogenated rosin methyl ester, 2g of hydrogenated rosin pentaerythritol ester, 3g of ethanolamine, and 90g of trimethylpentanediol to obtain the auxiliary agent;

[0035] S5: Mix 880g of metal powder with 120g of additives and add to a star mixer. Stir at 50 rpm and keep at room temperature for 1 hour to obtain solder paste.

[0036] Example 2

[0037] A type of through-hole printed solder paste for automotive electronic connectors is prepared according to the following steps:

[0038] S1: 1000g of copper-tin alloy is heated to 370℃ to melt and stirred for 35 minutes. Then, the welding alloy powder is obtained by centrifugal atomization. The mass of tin in the copper-tin alloy is 993g, the mass of copper is 7g, and the particle size of the welding alloy powder is 45μm.

[0039] S2: Heat 1000g of silver-copper-titanium alloy to 910℃ to melt and stir for 6 minutes, then cast and cool to form a silver-copper-titanium alloy block. The silver-copper-titanium alloy block is then ball-milled to obtain skeleton alloy powder. The mass of silver in the silver-copper-titanium alloy is 600g, the mass of copper is 280g, the mass of titanium is 120g, and the particle size of the skeleton alloy powder is 45μm.

[0040] S3: Place 990g of welding alloy powder and 10g of skeleton alloy powder into a granulator, add 1000g of isopropanol, the granulator stirring speed is 35 rpm, the granulation time is 2 hours, after granulation is completed, turn on the granulator and heat to 90℃ to dry completely to obtain metal powder.

[0041] S4: Mix 8g of hydrogenated rosin methyl ester, 6g of hydrogenated rosin pentaerythritol ester, 8g of ethanolamine, and 78g of trimethylpentanediol to obtain the auxiliary agent;

[0042] S5: Mix 920g of metal powder with 80g of additives and add to a star mixer. Stir at 60 rpm and keep at room temperature for 2 hours to obtain solder paste.

[0043] Example 3

[0044] A type of through-hole printed solder paste for automotive electronic connectors is prepared according to the following steps:

[0045] S1: 1000g of copper-tin alloy is heated to 360℃ to melt and stirred for 30 minutes. Then, it is centrifuged and atomized to obtain welding alloy powder. The mass of tin in the copper-tin alloy is 993g, the mass of copper is 7g, and the particle size of the welding alloy powder is 35μm.

[0046] S2: Heat 1000g of silver-copper-titanium alloy to 900℃ to melt and stir for 5 minutes, then cast and cool to form a silver-copper-titanium alloy block. Then, the silver-copper-titanium alloy block is ball-milled to obtain skeleton alloy powder. The mass of silver in the silver-copper-titanium alloy is 600g, the mass of copper is 280g, the mass of titanium is 120g, and the particle size of the skeleton alloy powder is 40μm.

[0047] S3: Place 987.5g of welding alloy powder and 12.5g of skeleton alloy powder into a granulator, add 1000g of isopropanol, the granulator stirring speed is 30 rpm, the granulation time is 1.5 hours, after granulation is completed, turn on the granulator and heat to 85℃ to dry completely to obtain metal powder.

[0048] S4: Mix 7g of hydrogenated rosin methyl ester, 4g of hydrogenated rosin pentaerythritol ester, 5g of ethanolamine, and 84g of trimethylpentanediol to obtain the auxiliary agent;

[0049] S5: Mix 900g of metal powder with 100g of additive and add to a star mixer. Stir at 55 rpm and keep at room temperature for 1.5 hours to obtain solder paste.

[0050] Comparative Example

[0051] Comparative Example 1

[0052] A type of through-hole printed solder paste for automotive electronic connectors is prepared according to the following steps:

[0053] S1: 1000g of copper-tin alloy is heated to 360℃ to melt and stirred for 30 minutes. Then, it is centrifuged and atomized to obtain welding alloy powder. The mass of tin in the copper-tin alloy is 993g, the mass of copper is 7g, and the particle size of the welding alloy powder is 35μm.

[0054] S3: Place 1000g of welding alloy powder into a granulator and add 1000g of isopropanol. The stirring speed of the granulator is 30 rpm and the granulation time is 1.5 hours. After granulation, turn on the granulator and heat it to 85℃ to dry it completely to obtain metal powder.

[0055] S4: Mix 7g of hydrogenated rosin methyl ester, 4g of hydrogenated rosin pentaerythritol ester, 5g of ethanolamine, and 84g of trimethylpentanediol to obtain the auxiliary agent;

[0056] S5: Mix 900g of metal powder with 100g of additive and add to a star mixer. Stir at 55 rpm and keep at room temperature for 1.5 hours to obtain solder paste.

[0057] Comparative Example 2

[0058] A type of through-hole printed solder paste for automotive electronic connectors is prepared according to the following steps:

[0059] S1: 1000g of copper-tin alloy is heated to 360℃ to melt and stirred for 30 minutes. Then, it is centrifuged and atomized to obtain welding alloy powder. The mass of tin in the copper-tin alloy is 993g, the mass of copper is 7g, and the particle size of the welding alloy powder is 35μm.

[0060] S2: Add 600g of silver powder, 280g of copper powder and 120g of titanium powder to a mixer and stir for 30 minutes to mix evenly to obtain a skeleton alloy powder. The particle size of silver powder, copper powder and titanium powder is 40μm.

[0061] S3: Place 987.5g of welding alloy powder and 12.5g of skeleton alloy powder into a granulator, add 1000g of isopropanol, the granulator stirring speed is 30 rpm, the granulation time is 1.5 hours, after granulation is completed, turn on the granulator and heat to 85℃ to dry completely to obtain metal powder.

[0062] S4: Mix 7g of hydrogenated rosin methyl ester, 4g of hydrogenated rosin pentaerythritol ester, 5g of ethanolamine, and 84g of trimethylpentanediol to obtain the auxiliary agent;

[0063] S5: Mix 900g of metal powder with 100g of additive and add to a star mixer. Stir at 55 rpm and keep at room temperature for 1.5 hours to obtain solder paste.

[0064] Comparative Example 3

[0065] A type of through-hole printed solder paste for automotive electronic connectors is prepared according to the following steps:

[0066] S1: Add 993g of tin powder and 7g of copper powder to a mixer and stir for 30 minutes to obtain a uniform welding alloy powder. The particle size of both tin powder and copper powder is 35μm.

[0067] S2: Heat 1000g of silver-copper-titanium alloy to 900℃ to melt and stir for 5 minutes, then cast and cool to form a silver-copper-titanium alloy block. Then, the silver-copper-titanium alloy block is ball-milled to obtain skeleton alloy powder. The mass of silver in the silver-copper-titanium alloy is 600g, the mass of copper is 280g, the mass of titanium is 120g, and the particle size of the skeleton alloy powder is 40μm.

[0068] S3: Place 987.5g of welding alloy powder and 12.5g of skeleton alloy powder into a granulator, add 1000g of isopropanol, the granulator stirring speed is 30 rpm, the granulation time is 1.5 hours, after granulation is completed, turn on the granulator and heat to 85℃ to dry completely to obtain metal powder.

[0069] S4: Mix 7g of hydrogenated rosin methyl ester, 4g of hydrogenated rosin pentaerythritol ester, 5g of ethanolamine, and 84g of trimethylpentanediol to obtain the auxiliary agent;

[0070] S5: Mix 900g of metal powder with 100g of additive and add to a star mixer. Stir at 55 rpm and keep at room temperature for 1.5 hours to obtain solder paste.

[0071] Comparative Example 4

[0072] A type of through-hole printed solder paste for automotive electronic connectors is prepared according to the following steps:

[0073] S1: Add 993g of tin powder and 7g of copper powder to a mixer and stir for 30 minutes to obtain a uniform welding alloy powder. The particle size of both tin powder and copper powder is 35μm.

[0074] S2: Add 600g of silver powder, 280g of copper powder and 120g of titanium powder to a mixer and stir for 30 minutes to mix evenly to obtain a skeleton alloy powder. The particle size of silver powder, copper powder and titanium powder is 40μm.

[0075] S3: Place 987.5g of welding alloy powder and 12.5g of skeleton alloy powder into a granulator, add 1000g of isopropanol, the granulator stirring speed is 30 rpm, the granulation time is 1.5 hours, after granulation is completed, turn on the granulator and heat to 85℃ to dry completely to obtain metal powder.

[0076] S4: Mix 7g of hydrogenated rosin methyl ester, 4g of hydrogenated rosin pentaerythritol ester, 5g of ethanolamine, and 84g of trimethylpentanediol to obtain the auxiliary agent;

[0077] S5: Mix 900g of metal powder with 100g of additive and add to a star mixer. Stir at 55 rpm and keep at room temperature for 1.5 hours to obtain solder paste.

[0078] Comparative Example 5

[0079] A type of through-hole printed solder paste for automotive electronic connectors is prepared according to the following steps:

[0080] S1: Add 993g of tin powder and 7g of copper powder to a mixer and stir for 30 minutes to obtain a uniform welding alloy powder. The particle size of both tin powder and copper powder is 35μm.

[0081] S2: Add 600g of silver powder, 280g of copper powder and 120g of titanium powder to a mixer and stir for 30 minutes to mix evenly to obtain a skeleton alloy powder. The particle size of silver powder, copper powder and titanium powder is 40μm.

[0082] S3: Place 987.5g of welding alloy powder and 12.5g of skeleton alloy powder into a granulator, add 1000g of isopropanol, the granulator is stirred at 30 rpm, the granulation time is 1.5 hours, after granulation is completed, turn on the granulator and heat to 85℃ to dry completely to obtain solder paste.

[0083] Performance testing

[0084] Prepare multiple identical PCB boards and connectors, and use the same parameters on the same printing press and reflow oven. Solder the PCB boards and connectors using the solder pastes prepared in Examples 1-3 and Comparative Examples 1-4. After the PCBAs prepared with the solder pastes prepared in Examples 1-3 and Comparative Examples 1-4 are soldered, they are subjected to temperature shock tests under the same conditions, followed by vibration verification and drop tests. The specific experimental methods and steps are as follows:

[0085] 1. Temperature cycling shock tests were conducted on the above four groups of samples (three in the example and four in the comparative example) at 0-125℃, with a heating and cooling rate of 15%, for a total of 800 cycles.

[0086] 2. After the temperature cycling is completed, vibration tests are performed on each sample. The vibration test conditions refer to the requirements of GB / T 2423.56-2006 standard. The plate is fixed on the vibration table with its plane perpendicular to the vibration axis. The vibration type is set to random vibration, the frequency range is 20-100Hz, the sweep rate is 6dB / oct, the acceleration spectral density is 0.5-1.0g² / Hz, and the test time is 100 minutes.

[0087] 3. Drop test: After completing the above two steps, the sample is placed on a drop test platform 1 meter high, according to the requirements of IEC60068-2-32 standard, and dropped 50 times.

[0088] 4. Perform X-ray scanning on the samples that have undergone the above experiments 1, 2, and 3, and count whether there are cracks or holes in the solder joints.

[0089] Table 1 Test Data Table

[0090] Are there any cracks or holes? quantity Example 1 none 0 Example 2 none 0 Example 3 none 0 Comparative Example 1 Yes, a crack has appeared between the connector pin and the solder. 2 Comparative Example 2 Yes, a crack has appeared between the connector pin and the solder. 2 Comparative Example 3 Yes, a crack has appeared between the connector pin and the solder. 2 Comparative Example 4 Yes, a crack has appeared between the connector pin and the solder. 2 Comparative Example 5 Yes, the connector pin is broken from the solder. /

[0091] As can be seen from Example 3 and Comparative Example 1, and Table 1, when no silver-copper-titanium alloy powder was added to the solder paste, cracks appeared at the solder joints of the soldered PCB after testing. This indicates that adding silver-copper-titanium alloy powder to the solder paste can greatly improve the structural strength of the solder joints, making it less likely for cracks to appear at the solder joints between the PCB and the connector, thus preventing poor connections.

[0092] As can be seen from Example 3 and Comparative Example 2, and Table 1, when silver powder, copper powder and titanium powder are simply added directly to the solder paste, cracks appeared at the solder joints of the soldered PCB after testing. This indicates that the silver-copper-titanium alloy needs to be melted and made into powder before being added to the solder paste to significantly improve the strength of the solder joints.

[0093] As can be seen from Example 3 and Comparative Example 3, and Table 1, when copper powder and tin powder are simply mixed directly, cracks appeared in the solder joints of the soldered PCB after testing. This indicates that the copper-tin alloy needs to be melted, made into powder, and then made into solder paste to significantly improve the strength of the solder joints.

[0094] Based on Example 3 and Comparative Example 4, and in conjunction with Table 1, it can be seen that when copper powder and tin powder are simply mixed directly, or when silver powder, copper powder, and titanium powder are directly added to the solder paste, cracks appear at the solder joints of the soldered PCB after testing. This indicates that it is necessary to melt the copper-tin alloy and the silver-copper-titanium alloy separately, make them into powder, and then make them into the solder paste to significantly improve the strength of the solder joints.

[0095] As can be seen from Example 3 and Comparative Example 5, and Table 1, the solder joint strength is extremely low when no additives are added to the solder paste.

[0096] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and modifications made to the above embodiments based on the present invention without departing from the scope of the present invention are within the scope of the present invention.

Claims

1. An automobile electronic connector through-hole printing solder paste, characterized by comprising: The solder paste comprises the following components by weight percentage: 88-92% metal powder, The remainder is an auxiliary agent. The metal powder contains 98-99% by mass of welding alloy powder and the balance of skeleton alloy powder. The welding alloy powder is tin-copper alloy powder and the skeleton alloy powder is silver-copper-titanium alloy powder. The additive contains 5-8% by mass of hydrogenated rosin methyl ester, 2-6% by mass of hydrogenated rosin pentaerythritol ester, 3-8% by mass of ethanolamine, and the balance being trimethylpentanediol.

2. The automotive electronic connector through-hole printed solder paste according to claim 1, characterized in that: The solder paste comprises the following components by weight percentage: 90% metal powder, The remainder is an auxiliary agent. The metal powder contains 98.75% by mass of welding alloy powder and 1.25% by mass of skeleton alloy powder. The welding alloy powder is tin-copper alloy powder, and the skeleton alloy powder is silver-copper-titanium alloy powder. The additive contains 7% hydrogenated rosin methyl ester, 4% hydrogenated rosin pentaerythritol ester, 5% ethanolamine, and the balance is trimethylpentanediol.

3. The automotive electronic connector through-hole printed solder paste according to claim 1, characterized in that: The mass ratio of tin to copper in the welding alloy powder is 99.3%:0.7%, and the mass ratio of silver, copper, and titanium in the skeleton alloy powder is 60%:28%:12%.

4. The automotive electronic connector through-hole printed solder paste according to claim 1, characterized in that: The particle size range of the welding alloy powder is 25-45 μm, and the particle size range of the skeleton alloy powder is 35-45 μm.

5. The solder paste according to claim 4, wherein: the solder paste is used for an automotive electronic connector through-hole soldering. The particle size of the welding alloy powder is 35 μm, and the particle size of the skeleton alloy powder is 40 μm. ​ 6. The method for preparing a solder paste for automotive electronic connector through-hole printing according to any one of claims 1 to 5, characterized in that: Includes the following steps: S1: Melt the copper-tin alloy at 350-370℃ and stir for 25-35 minutes, then atomize it by centrifugation to obtain welding alloy powder; S2: Heat the silver-copper-titanium alloy to 890-910℃ to melt and stir for 4-6 minutes, then cast and cool it into a silver-copper-titanium alloy block. Then, the silver-copper-titanium alloy block is ball-milled to obtain skeleton alloy powder. S3: Place the welding alloy powder and the skeleton alloy powder into the granulator, and add isopropanol of the same mass as the welding alloy powder and the skeleton alloy powder. The stirring speed of the granulator is 25-35 rpm, and the granulation time is 1-2 hours. After granulation, turn on the granulator and heat it to 80-90℃ to dry it completely to obtain metal powder. S4: An auxiliary agent is obtained by mixing hydrogenated rosin methyl ester, hydrogenated rosin pentaerythritol ester, ethanolamine, and trimethylpentanediol; S5: Mix the metal powder with the additives and add them to a star mixer. Stir at 50-60 rpm and keep at room temperature for 1-2 hours to obtain solder paste.

7. The method for preparing a solder paste for through-hole printing of an automotive electronic connector according to claim 6, wherein: In step S1, the mass ratio of tin to copper in the welding alloy powder is 99.3%:0.7%; in step S3, the mass ratio of silver, copper, and titanium in the skeleton alloy powder is 60%:28%:12%.

8. The method for preparing through-hole printed solder paste for automotive electronic connectors according to claim 6, characterized in that: In step S4, the additive contains 5-8% by mass of hydrogenated rosin methyl ester, 2-6% by mass of hydrogenated rosin pentaerythritol ester, 3-8% by mass of ethanolamine, and the balance being trimethylpentanediol.

9. The method for preparing through-hole printed solder paste for automotive electronic connectors according to claim 6, characterized in that: In step S5, the solder paste contains 88-92% metal powder by mass, with the remainder being additives.

10. The method for preparing through-hole printed solder paste for automotive electronic connectors according to claim 6, characterized in that: The particle size of the welding alloy powder ranges from 25 to 45 μm, and the particle size of the skeleton alloy powder ranges from 35 to 45 μm.