Halogen-free high-impedance soldering flux and preparation method

Abstract

The invention relates to a halogen-free high-impedance soldering flux and a preparation method. The halogen-free high-impedance soldering flux is characterized by containing the following components according to weight: 2-8% of organic acid activating agent, 0.1-2% of non-ionic surface active agent, 3-8% of organic solvent having a high boiling point, 0.01-0.5% corrosion inhibitor and the balance of modified rosin. The preparation method comprises the following steps: adding modified rosin into a container for heating and stirring until the modified rosin is completely fused; adding the organic acid activating agent, the non-ionic surface active agent, the corrosion inhibitor and the organic solvent having a high boiling point in sequence at a temperature of 130-150 DEG C, and continuing to stir for 20-30 minutes to obtain the soldering flux. The halogen-free high-impedance soldering flux has excellent welding assisting effect to lead-free solder, is halogen-free, has no harm to health and environment, causes little splashing, has less residue after welding, has high insulation resistance on the surface, and ensures the advantage and effect of reliability of electronic products after welding.

Description

technical field [0001] The invention relates to a halogen-free high-impedance soldering flux, in particular to a halogen-free high-impedance soldering flux for lead-free solder wires, and belongs to the field of soldering materials for electronic and electrical products. [0002] The invention also relates to a preparation method of the halogen-free high-resistance soldering flux. Background technique [0003] In recent years, due to the increasing awareness of human environmental protection and the successive promulgation of lead prohibition laws, electronic packaging solder has gradually transitioned from traditional leaded solder to lead-free solder, of which Sn-Cu and Sn-Ag- Cu-based solders are recognized in the industry as better and commercialized lead-free solders. However, their melting point is 30-45°C higher than the 183°C of traditional Sn-Pb eutectic solders. Traditional Sn-Pb It is difficult for the flux used for solder wire to meet the soldering requirements ...

AI Technical Summary

Problems solved by technology

[0003] In recent years, due to the increasing awareness of human environmental protection and the successive promulgation of lead prohibition laws, electronic packaging solder has gradually transitioned from traditional leaded solder to lead-free solder, of which Sn-Cu and Sn-Ag- Cu-based solders are recognized in the industry as better and commercialized lead-free solders. However, their melting point is 30-45°C higher than the 183°C of traditional Sn-Pb eutectic solders. Traditional Sn-Pb Flux for solder wire is difficult to meet the soldering requirements of lead-free process

[0004] To this end, major electronics manufacturing companies and solder manufacturers have devoted themselves to the research of highly active fluxes for lead-free solder, and have achieved remarkable results. They have developed a variety of fluxes for lead-free solder wires, but comprehensive analysis and research The patents for fluxes for lead-free solder wires that have appeared in China today found that most of the fluxes for lead-free solder wires in China currently use halogen-containing compounds or salts. However, this type of flux has a lot of halogen residues after soldering. The reliability of the use has brought great safety hazards, especially in the case of high temperature and high humidity, such as the high ambient temperature and high air humidity during the rainy season in southern my country, this type of halogen-containing flux makes the reliability of electronic products facing a huge test

For example, Chinese patent 200710022404.0 discloses a flux for lead-free solder wire, which uses halogen-containing compounds such as dibromobutene diol, dibromoethylbenzene, cetylpyridinium bromide, and amine salts. , the halogen residue after soldering is high. However, as the package size of electronic and electrical products continues to shrink and the pitch of component pins becomes smaller and smaller, the halogen residue on the surface of the circuit board often moves directional in the electric field environment, resulting in The surface insulation resistance decreases, which can easily lead to short circuit between component pins, and eventually lead to component failure; Chinese patent 200810025124. Halogen-containing compounds such as ethylene glycol and 5-chlorosalicylic acid have many halogen residues after soldering, and are easy to corrode circuit boards and solder joints during the use of components, reducing the surface insulation resistance of circuit boards and component pins. Ultimately, it will cause a short circuit between the pins of the component, making the component fail during service, and cannot meet the high reliability requirements of high-end electronic products

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