Halogenless soldering flux for tin and bismuth low-temperature solder wire and preparation method thereof

Abstract

The invention discloses a halogenless soldering flux for a tin and bismuth low-temperature solder wire, which comprises the following components in percentage by total weight: 3-5 percent of benzene acid activating agent, 1-2 percent of carbazole active strengthening agent, 0.5-1.0 percent of alcohol amine inhibitor, 5-10 percent of resin softening agent and the balance of resin, wherein the resin is at least one of polyamide resin, fully-hydrogenated rosin resin and modified rosin resin. The halogenless soldering flux has the beneficial effects that the benzene acid activating agent and the carbazole active strengthening agent are mutually matched, so that the welding activity is greatly improved, a metal oxide film is effectively removed, and the welding wettability is improved; meanwhile, the alcohol amine inhibitor is adopted for preventing the secondary oxidation of a pad, components are not corroded after the completion of welding, the insulation resistance is high, and residues after welding are prevented from blackening; with the adoption of the resin softening agent, the residues are not only stable, but also cool and transparent in appearance; and the tin and bismuth low-temperature welding requirements in the electronic industry can be met.

Description

technical field [0001] The invention relates to a halogen-free flux for tin wire, in particular to a halogen-free flux for tin-bismuth low-temperature tin wire and a preparation method thereof. Background technique [0002] In recent years, with the rapid development of the electronics industry, more and more lead-free tin wires have been used. The main components of lead-free tin wire alloy are tin-copper and tin-silver-copper, both of which have melting points as high as 218°C. The soldering temperature should not be too high, so the application of tin-bismuth low-temperature tin wire has been rapidly developed. The active agents in the flux used in traditional lead-free tin wire are mainly organic acids (such as succinic acid, adipic acid, etc.) or organic halides (dimethylamine hydrochloride, cyclohexylamine hydrochloride, etc.), but due to their The acidity is too strong, and it is easy to produce bismuth oxides when used in the welding of tin-bismuth low-temperature ...

AI Technical Summary

Problems solved by technology

The active agents in the flux used in traditional lead-free tin wire are mainly organic acids (such as succinic acid, adipic acid, etc.) or organic halides (dimethylamine hydrochloride, cyclohexylamine hydrochloride, etc.), but due to their The acidity is too strong, and it is easy to produce bismuth oxide when used in the welding of tin-bismuth low-temperature tin wire, and the residue of the solder joint becomes black; and because the welding temperature is lower than 200°C, the organic acid or organic halide cannot be effectively dissolved after welding. Volatile, remaining in rosin, resulting in increased surface insulation resistance, resulting in the risk of corrosion and short circuit, so there is an urgent need for a flux suitable for tin-bismuth low-temperature tin wire

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