Method for preparing solution of tin methane sulfonate

Abstract

The invention relates to a method for preparing a solution of tin methane sulfonate for electroplating. The method is characterized by comprising the following steps that: 1) an anion exchange membrane is used for dividing an electrolytic cell into a cathode chamber and an anode chamber, wherein the electrolyte used in the anode chamber is a solution of methane sulfonic acid with the mass concentration of between 20 and 40 percent, and the electrolyte used in the cathode chamber is a solution of methane sulfonic acid with the mass concentration of between 10 and 50 percent; the anode in the anode chamber is made of a tin plate or tin flower, and the cathode in the cathode chamber is made of a tin plate or copper plate; and 2) the anode and the cathode are connected with a DC power supply for electrolysis, the electrolytic temperature is between 20 and 60 DEG C, and under the action of the DC with the voltage of 1.8 to 3V, the anode is subjected to anodic dissolution and enters the anode chamber; and when the concentration of tin ion in the anode chamber reaches between 100 and 130g / L, the electrolysis stops, and the electrolyte in the anode chamber is taken out and filtered, and the filtrate is subjected to vacuum concentration at a temperature of between 40 and 120 DEG C, so that the solution of tin methane sulfonate, of which the content of tin ion is 300 to 310g / L, can be obtained. The method has the advantages of less equipment investment, simple process and high product purity.

Description

technical field

[0001] The invention belongs to the technical field of special chemicals for electroplating, and in particular relates to a method for preparing an aqueous solution of tin methanesulfonate for electronic electroplating. Background technique

[0002] Tin and tin-lead alloy coatings have been widely used in the electronics industry due to their excellent corrosion resistance and solderability. However, in recent years, due to the great restriction of lead, the electroplating tin process will become the main plating type of solderable coating in electronic electroplating. Previous tin plating baths were mainly based on highly polluting fluoroborates, phenol sulfonates, and halides. In recent years, the sulfate tin plating process has greatly improved environmental pollution, but the baths are unstable. Methanesulfonate tin plating can basically solve the above problems and has high industrial application value. Therefore, the tin plating process of tin methane...