Lead-free solder paste with good fluidity and no agglomeration and preparation method thereof

Abstract

The invention discloses a lead-free solder paste with good fluidity and no agglomeration and a preparation method thereof. The components are calculated by mass percentage as follows: 40%-50% of rosin raw materials, 35%-45% of solvents, 1%-6% of active agents, 8%-12% of thixotropic agents and 1%-3% of other additives. The invention has the following beneficial effects: by adding an emulsification step in the preparation process of the lead-free solder paste, the quality of the solder paste is improved, and the fluidity of the solder paste is further improved, so that the solder paste can be used more smoothly when used, and the probability of agglomeration caused by the environment is reduced; multiple grinding operations are added after the emulsification step to improve the quality of the solder paste product itself, and it is essentially ensured that no agglomeration occurs inside the solder paste, so that poor printing and insufficient tin leakage at the level of fine solder joints are avoided, resulting in no conduction between electronic circuits and components, and causing failure of poorly functioning solder joints.

Description

Technical Field

[0001] The invention relates to the technical field of solder paste preparation, in particular to a lead-free solder paste with good fluidity and no agglomeration and a preparation method thereof. Background Art

[0002] In recent years, electronic products have been constantly updated and replaced with the continuous advancement of science and technology and people's needs. A typical representative of this is the increasing trend towards refinement and miniaturization, which is a big challenge for the mounting of electronic components on electronic circuit boards. In order to achieve this goal, the requirements for SMT surface mounting solder paste are stringent in terms of new materials. The current industry solder paste products can meet 0.4 mm pitch screen printing. When the pitch is less than 0.4 mm and is between 0.3 mm and 0.2 mm, the current industry solder paste has agglomeration inside, which will cause poor printing and insufficient tin leakage at the level of fine solder joints, resulting in no conduction between electronic circuits and components, resulting in poor function and failure of solder joints. Therefore, the present invention proposes a lead-free solder paste with good fluidity and no agglomeration. Summary of the invention

[0003] The object of the present invention is to provide a lead-free solder paste with good fluidity and no agglomeration and a preparation method thereof, so as to solve the problems raised in the above background technology.

[0004] To achieve the above purpose, the present invention provides the following technical solutions

[0005] A lead-free solder paste with good fluidity and no agglomeration, wherein the components are as follows by mass percentage: rosin raw material 40%-50%, solvent 35%-45%, active agent 1%-6%, thixotropic agent 8%-12% and other additives 1%-3%;

[0006] A method for preparing a lead-free solder paste with good fluidity and no agglomeration, specifically comprising the following steps:

[0007] S1, mixing the rosin raw material and the solvent in a specified ratio to obtain a mixed raw material;

[0008] S2, adding the mixed raw material obtained in S1 to a vacuum emulsifying stirring device for preliminary stirring, then adding an active agent according to a proportion for secondary stirring, then adding a thixotropic agent according to a proportion for third stirring, and finally adding other additives according to a proportion for final stirring to obtain an emulsified product;

[0009] S3, adding the emulsified product obtained in S2 into a grinding device for grinding, and after the grinding is completed, mixing the ground material with the tin-based alloy powder to obtain a finished solder paste, and finally packaging it.

[0010] As a preferred embodiment of the present invention: the rosin raw material is preferably one of KE604, AX-E, RHR125 and RHR101, the solvent is preferably one of diethylene glycol monohexyl ether, diethylene glycol monobutyl ether and tripropylene glycol butyl ether, the activator is preferably one or more of sebacic acid, succinic acid, malonic acid, NA anhydride, dihydroxymethylpropionic acid and adipic acid, the thixotropic agent is preferably one of modified hydrogenated castor oil, PEG4000 and stearic acid, and the other additives are preferably one or more of antioxidant 1010, triethanolamine and BYK410.

[0011] As a preferred solution of the present invention: the specific operation steps of the vacuum emulsification device of S2 are as follows:

[0012] S2.1, first add the mixed raw materials obtained in S1, then increase the temperature of the vacuum emulsification device to 120°C and stir for 120 minutes;

[0013] S2.2, lower the temperature of the vacuum emulsification device to 110°C, then add the active agent and stir for 120 minutes;

[0014] S2.3, lower the temperature of the vacuum emulsification device to 100°C, then add the thixotropic agent and stir for 60 minutes;

[0015] S2.4. Lower the temperature of the vacuum emulsification device to 90°C, then add other additives, then lower the temperature of the vacuum emulsification device to 22°C, and stir for 30 minutes to obtain an emulsified product.

[0016] As a preferred solution of the present invention: before grinding, the grinding equipment in S3 needs to load the emulsified product obtained in S2 onto the first grinding roller and the second grinding roller for primary grinding, and then adhere the emulsified product after the primary grinding to the second grinding roller and cooperate with the third grinding roller for secondary grinding.

[0017] As a preferred solution of the present invention: the rotation speed of the first grinding roller is 29 revolutions per minute, the rotation speed of the second grinding roller is 88 revolutions per minute, and the rotation speed of the third grinding roller is 264 revolutions per minute.

[0018] As a preferred solution of the present invention, the specific steps of mixing the ground material in S3 with the tin-based alloy powder are as follows:

[0019] S3.1, weighing tin-based alloy powder according to the ratio of ground material to tin-based alloy powder of 100:1 to obtain tin-based alloy powder raw material;

[0020] S3.2, add the ground material into a mixer, and then add one sixth of the tin-based alloy powder raw material in S3.1 into the mixer for initial mixing;

[0021] S3.3, adding one third of the tin-based alloy powder raw material in S3.1 into a mixing and stirring machine, and performing secondary mixing and stirring;

[0022] S3.4. Add half of the tin-based alloy powder raw material in S3.1 into a mixing and stirring machine, and perform final mixing and stirring to obtain a finished solder paste.

[0023] As a preferred solution of the present invention: in the mixing and stirring operation in S3.2, the rotation speed of the stirring rod is 300 revolutions per second, and the stirring time is set at one minute per 8 kg of the total mass of the raw materials.

[0024] As a preferred solution of the present invention: in the mixing and stirring operation in S3.3, the rotation speed of the stirring rod is 500 revolutions per second, and the stirring time is set at two minutes for every 8 kg of the total mass of the raw materials.

[0025] As a preferred solution of the present invention: in the mixing and stirring operation in S3.4, the rotation speed of the stirring rod is 800 revolutions per second, and the stirring time is set at five minutes for every 8 kg of the total mass of the raw materials.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The present invention improves the quality of the solder paste and further improves the fluidity of the solder paste by adding an emulsification step during the preparation of the lead-free solder paste, so that the solder paste can be used more smoothly and the probability of agglomeration caused by the environment is reduced; multiple grinding operations are added after the emulsification step to improve the quality of the solder paste product itself, and essentially ensure that the solder paste will not agglomerate, thereby avoiding poor printing and insufficient tin leakage at the level of fine solder joints, resulting in no conduction between electronic circuits and components, and causing poor function of the solder joint failure. DETAILED DESCRIPTION

[0028] The present invention provides a technical solution:

[0029] A lead-free solder paste with good fluidity and no agglomeration, wherein the components are as follows by mass percentage: rosin raw material 40%-50%, solvent 35%-45%, active agent 1%-6%, thixotropic agent 8%-12% and other additives 1%-3%;

[0030] A method for preparing a lead-free solder paste with good fluidity and no agglomeration, specifically comprising the following steps:

[0031] S1, mixing the rosin raw material and the solvent in a specified ratio to obtain a mixed raw material;

[0032] S2, adding the mixed raw material obtained in S1 to a vacuum emulsifying stirring device for preliminary stirring, then adding an active agent according to a proportion for secondary stirring, then adding a thixotropic agent according to a proportion for third stirring, and finally adding other additives according to a proportion for final stirring to obtain an emulsified product;

[0033] S3, adding the emulsified product obtained in S2 into a grinding device for grinding, and after the grinding is completed, mixing the ground material with the tin-based alloy powder to obtain a finished solder paste, and finally packaging it.

[0034] Furthermore, the rosin raw material is preferably one of KE604, AX-E, RHR125 and RHR101, the solvent is preferably one of diethylene glycol monohexyl ether, diethylene glycol monobutyl ether and tripropylene glycol butyl ether, the active agent is preferably one or more of sebacic acid, succinic acid, malonic acid, NA anhydride, dihydroxymethylpropionic acid and adipic acid, the thixotropic agent is preferably one of modified hydrogenated castor oil, PEG4000 and stearic acid, and other additives are preferably one or more of antioxidant 1010, triethanolamine and BYK410.

[0035] Furthermore, the specific operation steps of the vacuum emulsification device of S2 are as follows:

[0036] S2.1, first add the mixed raw materials obtained in S1, then increase the temperature of the vacuum emulsification device to 120°C and stir for 120 minutes;

[0037] S2.2, lower the temperature of the vacuum emulsification device to 110°C, then add the active agent and stir for 120 minutes;

[0038] S2.3, lower the temperature of the vacuum emulsification device to 100°C, then add the thixotropic agent and stir for 60 minutes;

[0039] S2.4. Lower the temperature of the vacuum emulsification device to 90°C, then add other additives, then lower the temperature of the vacuum emulsification device to 22°C, and stir for 30 minutes to obtain an emulsified product.

[0040] Furthermore, before grinding, the grinding equipment in S3 needs to load the emulsified product obtained in S2 onto the first grinding roller and the second grinding roller for primary grinding, and then adhere the emulsified product after the primary grinding to the second grinding roller and cooperate with the third grinding roller for secondary grinding.

[0041] Furthermore, the rotation speed of the first grinding roller is 29 revolutions per minute, the rotation speed of the second grinding roller is 88 revolutions per minute, and the rotation speed of the third grinding roller is 264 revolutions per minute.

[0042] Furthermore, the specific steps of mixing the ground material in S3 with the tin-based alloy powder are as follows:

[0043] S3.1, weighing tin-based alloy powder according to the ratio of ground material to tin-based alloy powder of 100:1 to obtain tin-based alloy powder raw material;

[0044] S3.2, add the ground material into a mixer, and then add one sixth of the tin-based alloy powder raw material in S3.1 into the mixer for initial mixing;

[0045] S3.3, adding one third of the tin-based alloy powder raw material in S3.1 into a mixing and stirring machine, and performing secondary mixing and stirring;

[0046] S3.4. Add half of the tin-based alloy powder raw material in S3.1 into a mixing and stirring machine, and perform final mixing and stirring to obtain a finished solder paste.

[0047] Furthermore, in the mixing and stirring operation in S3.2, the rotation speed of the stirring rod is 300 revolutions per second, and the stirring time is set at one minute per 8 kg of the total mass of the raw materials.

[0048] Furthermore, in the mixing and stirring operation in S3.3, the rotation speed of the stirring rod is 500 revolutions per second, and the stirring time is set at two minutes for every 8 kg of the total mass of the raw materials.

[0049] Furthermore, in the mixing and stirring operation in S3.4, the rotation speed of the stirring rod is 800 revolutions per second, and the stirring time is set at five minutes for every 8 kg of the total mass of the raw materials.

[0050] Example 1

[0051] The invention discloses a lead-free solder paste with good fluidity and no agglomeration. The components thereof are calculated by weight percentage as follows: 45% of rosin raw materials, 40% of solvents, 4% of active agents, 9% of thixotropic agents and 2% of other additives.

[0052] In this embodiment, the rosin raw material is KE604, the solvent is diethylene glycol monohexyl ether, the activator is dimethylol propionic acid and succinic acid, the thixotropic agent is modified hydrogenated castor oil, and other additives are antioxidant 1010 and triethanolamine.

[0053] In this embodiment, the specific operation steps are as follows:

[0054] S1, mixing KE604 and diethylene glycol monohexyl ether in a specified ratio to obtain a mixed raw material;

[0055] S2, adding the mixed raw material obtained in S1 to a vacuum emulsification stirring device, raising the temperature of the vacuum emulsification device to 120°C, stirring for 120 minutes, then lowering the temperature of the vacuum emulsification device to 110°C, then adding dimethylolpropionic acid and succinic acid and stirring for 120 minutes, then lowering the temperature of the vacuum emulsification device to 100°C, then adding modified hydrogenated castor oil and stirring for 60 minutes, lowering the temperature of the vacuum emulsification device to 90°C, then adding antioxidant 1010 and triethanolamine, then lowering the temperature of the vacuum emulsification device to 22°C, and stirring for 30 minutes to obtain an emulsified product;

[0056] S3, feeding the emulsified product obtained in S2 to the first grinding roller and the second grinding roller for primary grinding, and then adhering the emulsified product after the primary grinding to the second grinding roller, and performing secondary grinding with the third grinding roller, wherein the rotation speed of the first grinding roller is 29 revolutions per minute, the rotation speed of the second grinding roller is 88 revolutions per minute, and the rotation speed of the third grinding roller is 264 revolutions per minute, to obtain a ground material;

[0057] S4. Weigh tin-based alloy powder according to the ratio of ground material to tin-based alloy powder of 100:1 to obtain tin-based alloy powder raw material, add the ground material into a mixing and blending machine, then add one-sixth of the tin-based alloy powder raw material into the mixing and blending machine, set the rotation speed of the stirring rod to 300 revolutions per second, and set the stirring time to one minute per 8 kg of the total mass of the raw material for initial mixing and blending, then add one-third of the tin-based alloy powder raw material into the mixing and blending machine, set the rotation speed of the stirring rod to 500 revolutions per second, and set the stirring time to two minutes per 8 kg of the total mass of the raw material for secondary mixing and blending, finally add one-half of the tin-based alloy powder raw material into the mixing and blending machine, set the rotation speed of the stirring rod to 800 revolutions per second, and set the stirring time to five minutes per 8 kg of the total mass of the raw material for final mixing and blending to obtain a finished solder paste.

[0058] Example 2

[0059] The invention discloses a lead-free solder paste with good fluidity and no agglomeration. The components thereof are calculated by weight percentage as follows: 45% of rosin raw materials, 40% of solvents, 4% of active agents, 9% of thixotropic agents and 2% of other additives.

[0060] In this embodiment, the rosin raw material is AX-E, the solvent is diethylene glycol monobutyl ether, the activator is malonic acid and succinic acid, the thixotropic agent is stearic acid, and the other additives are antioxidants 1010 and BYK410.

[0061] In this embodiment, the specific operation steps are as follows:

[0062] S1, mixing AX-E and diethylene glycol monobutyl ether in a specified ratio to obtain a mixed raw material;

[0063] S2, adding the mixed raw material obtained in S1 to a vacuum emulsification stirring device, raising the temperature of the vacuum emulsification device to 120°C, stirring for 120 minutes, then lowering the temperature of the vacuum emulsification device to 110°C, then adding malonic acid and succinic acid and stirring for 120 minutes, then lowering the temperature of the vacuum emulsification device to 100°C, then adding stearic acid and stirring for 60 minutes, lowering the temperature of the vacuum emulsification device to 90°C, then adding antioxidants 1010 and BYK410, then lowering the temperature of the vacuum emulsification device to 22°C, and stirring for 30 minutes to obtain an emulsified product;

[0064] S3, feeding the emulsified product obtained in S2 to the first grinding roller and the second grinding roller for primary grinding, and then adhering the emulsified product after the primary grinding to the second grinding roller, and performing secondary grinding with the third grinding roller, wherein the rotation speed of the first grinding roller is 29 revolutions per minute, the rotation speed of the second grinding roller is 88 revolutions per minute, and the rotation speed of the third grinding roller is 264 revolutions per minute, to obtain a ground material;

[0065] S4. Weigh tin-based alloy powder according to the ratio of ground material to tin-based alloy powder of 100:1 to obtain tin-based alloy powder raw material, add the ground material into a mixing and blending machine, then add one-sixth of the tin-based alloy powder raw material into the mixing and blending machine, set the rotation speed of the stirring rod to 300 revolutions per second, and set the stirring time to one minute per 8 kg of the total mass of the raw material for initial mixing and blending, then add one-third of the tin-based alloy powder raw material into the mixing and blending machine, set the rotation speed of the stirring rod to 500 revolutions per second, and set the stirring time to two minutes per 8 kg of the total mass of the raw material for secondary mixing and blending, finally add one-half of the tin-based alloy powder raw material into the mixing and blending machine, set the rotation speed of the stirring rod to 800 revolutions per second, and set the stirring time to five minutes per 8 kg of the total mass of the raw material for final mixing and blending to obtain a finished solder paste.

[0066] Embodiment 3,

[0067] The invention discloses a lead-free solder paste with good fluidity and no agglomeration. The components thereof are calculated by weight percentage as follows: 45% of rosin raw materials, 40% of solvents, 4% of active agents, 9% of thixotropic agents and 2% of other additives.

[0068] In this embodiment, the rosin raw material is RHR125, the solvent is tripropylene glycol butyl ether, the activator is dimethylol propionic acid and adipic acid, the thixotropic agent is PEG4000, and other additives are antioxidant 1010 and triethanolamine.

[0069] In this embodiment, the specific operation steps are as follows:

[0070] S1, mixing RHR125 and tripropylene glycol butyl ether in a specified ratio to obtain a mixed raw material;

[0071] S2, adding the mixed raw material obtained in S1 to a vacuum emulsifying stirring device, raising the temperature of the vacuum emulsifying device to 120°C, stirring for 120 minutes, then lowering the temperature of the vacuum emulsifying device to 110°C, then adding dimethylolpropionic acid and adipic acid and stirring for 120 minutes, then lowering the temperature of the vacuum emulsifying device to 100°C, then adding PEG4000 and stirring for 60 minutes, lowering the temperature of the vacuum emulsifying device to 90°C, then adding antioxidant 1010 and triethanolamine, then lowering the temperature of the vacuum emulsifying device to 22°C, and stirring for 30 minutes to obtain an emulsified product;

[0072] S3, feeding the emulsified product obtained in S2 to the first grinding roller and the second grinding roller for primary grinding, and then adhering the emulsified product after the primary grinding to the second grinding roller, and performing secondary grinding with the third grinding roller, wherein the rotation speed of the first grinding roller is 29 revolutions per minute, the rotation speed of the second grinding roller is 88 revolutions per minute, and the rotation speed of the third grinding roller is 264 revolutions per minute, to obtain a ground material;

[0073] S4. Weigh tin-based alloy powder according to the ratio of ground material to tin-based alloy powder of 100:1 to obtain tin-based alloy powder raw material, add the ground material into a mixing and blending machine, then add one-sixth of the tin-based alloy powder raw material into the mixing and blending machine, set the rotation speed of the stirring rod to 300 revolutions per second, and set the stirring time to one minute per 8 kg of the total mass of the raw material for initial mixing and blending, then add one-third of the tin-based alloy powder raw material into the mixing and blending machine, set the rotation speed of the stirring rod to 500 revolutions per second, and set the stirring time to two minutes per 8 kg of the total mass of the raw material for secondary mixing and blending, finally add one-half of the tin-based alloy powder raw material into the mixing and blending machine, set the rotation speed of the stirring rod to 800 revolutions per second, and set the stirring time to five minutes per 8 kg of the total mass of the raw material for final mixing and blending to obtain a finished solder paste.

[0074] The actual application performance of the lead-free solder paste prepared in this application: The results are as follows

[0075]

[0076]

[0077] It can be seen from the above table that in the process of producing lead-free solder paste, by adding the preparation method proposed in the present invention, in a combination of emulsification and grinding, it can be effectively guaranteed that the internal agglomeration of the solder paste product is reduced. After multiple grindings, it can be guaranteed that there will be no agglomeration inside the solder paste, which effectively reduces the occurrence of poor printing and insufficient tin leakage at the level of fine solder joints, resulting in no conduction between electronic circuits and components, and causing poor functional solder joints. Failure.

[0078] In the present invention, unless otherwise clearly stipulated and limited, the terms such as "installation", "setting", "connection", "fixation" and "screw-on" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. Unless otherwise clearly defined, ordinary technicians in this field can understand the specific meanings of the above terms in the present invention according to the specific circumstances.

[0079] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A lead-free solder paste with good fluidity and no agglomeration, characterized in that: The components are calculated by mass percentage as follows: rosin raw materials 45%-50%, solvents 40%-45%, active agents 1%-6%, thixotropic agents 8%-12% and other additives 1%-2%; The rosin raw material is one of KE604, AX-E, RHR125 and RHR101, the solvent is one of diethylene glycol monohexyl ether, diethylene glycol monobutyl ether and tripropylene glycol butyl ether, the active agent is one or more of sebacic acid, succinic acid, malonic acid, NA anhydride, dimethylol propionic acid and adipic acid, the thixotropic agent is one of modified hydrogenated castor oil, PEG4000 and stearic acid, and the other additives are one or more of antioxidant 1010, triethanolamine and BYK410; A method for preparing a lead-free solder paste with good fluidity and no agglomeration, specifically comprising the following steps: S1, mixing the rosin raw material and the solvent in a specified ratio to obtain a mixed raw material; S2, adding the mixed raw material obtained in S1 to a vacuum emulsifying stirring device for preliminary stirring, then adding an active agent according to a proportion for secondary stirring, then adding a thixotropic agent according to a proportion for third stirring, and finally adding other additives according to a proportion for final stirring to obtain an emulsified product; S3, adding the emulsified product obtained in S2 into a grinding device for grinding, and after the grinding is completed, mixing the ground material with the tin-based alloy powder to obtain a finished solder paste, and finally packaging it; The specific operation steps of the vacuum emulsification device of S2 are as follows: S2.1, first add the mixed raw materials obtained in S1, then increase the temperature of the vacuum emulsification device to 120°C and stir for 120 minutes; S2.2, lower the temperature of the vacuum emulsification device to 110°C, then add the active agent and stir for 120 minutes; S2.3, lower the temperature of the vacuum emulsification device to 100°C, then add the thixotropic agent and stir for 60 minutes; S2.4, lowering the temperature of the vacuum emulsification device to 90°C, then adding other additives, and then lowering the temperature of the vacuum emulsification device to 22°C, and stirring for 30 minutes to obtain an emulsified product; The specific steps of mixing the ground material and the tin-based alloy powder in S3 are as follows: S3.1, weighing tin-based alloy powder according to the ratio of ground material to tin-based alloy powder of 100:1 to obtain tin-based alloy powder raw material; S3.2, add the ground material into a mixer, and then add one sixth of the tin-based alloy powder raw material in S3.1 into the mixer for initial mixing; S3.3, adding one third of the tin-based alloy powder raw material in S3.1 into a mixing and stirring machine, and performing secondary mixing and stirring; S3.4, adding half of the tin-based alloy powder raw material in S3.1 into a mixing and stirring machine, and performing final mixing and stirring to obtain a finished solder paste; Before grinding, the grinding equipment in S3 needs to feed the emulsified product obtained in S2 to the first grinding roller and the second grinding roller for primary grinding, and then adhere the emulsified product after the primary grinding to the second grinding roller and cooperate with the third grinding roller for secondary grinding; A method for preparing a lead-free solder paste with good fluidity and no agglomeration, which combines emulsification and grinding to ensure that no agglomeration occurs inside the solder paste after four times of grinding.

2. The lead-free solder paste with good fluidity and no agglomeration according to claim 1, characterized in that: The rotation speed of the first grinding roller is 29 revolutions per minute, the rotation speed of the second grinding roller is 88 revolutions per minute, and the rotation speed of the third grinding roller is 264 revolutions per minute.

3. The lead-free solder paste with good fluidity and no agglomeration according to claim 2, characterized in that: In the mixing and stirring operation in S3.2, the rotation speed of the stirring rod is 300 revolutions per second, and the stirring time is set at one minute per 8 kg of the total mass of the raw materials.

4. The lead-free solder paste with good fluidity and no agglomeration according to claim 1, characterized in that: In the mixing and stirring operation in S3.3, the rotation speed of the stirring rod is 500 revolutions per second, and the stirring time is set at two minutes per 8 kg of the total mass of the raw materials.

5. The lead-free solder paste with good fluidity and no agglomeration according to claim 1, characterized in that: In the mixing and stirring operation in S3.4, the rotation speed of the stirring rod is 800 revolutions per second, and the stirring time is set at five minutes for every 8 kg of the total mass of the raw materials.

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