Method for preparing spherical silver powder by using hydroxymethyl amino condensation product as dispersant

Abstract

The invention relates to a method for preparing spherical silver powder by using a hydroxymethyl amino condensation product as a dispersant. The obtained superfine spherical silver powder can be used for preparing conductive slurry in the electronic industry. The method comprises the following steps: (1) preparing the hydroxymethyl amino condensation product serving as the dispersant by using an amine compound and formaldehyde solution; and (2) preparing mixed solution of a reducing agent and the dispersant, adjusting the pH value of the mixed solution of the reducing agent and the dispersantby using aqueous ammonia or nitric acid solution, adding silver nitrate solution into the mixed solution consisting of the reducing agent and the dispersant while stirring, and after the reaction is completed, standing, filtering, washing and drying the reaction product to obtain the superfine silver powder with different granularity from 0.5 to 3 microns.

Description

technical field [0001] The invention relates to a preparation method of silver powder, in particular to a preparation method of spherical silver powder using methylolamine condensate as a dispersant. Background technique [0002] Ultrafine silver powder is widely used in the electronics industry. In addition to producing various conductive pastes, it can also be used for internal and external electrodes of printed circuits and electronic components. With the rapid development of microelectronics technology and electronic component manufacturing in my country, the precision and miniaturization of printed circuits and electronic components require silver powder to develop in the direction of high purity, high dispersion and ultrafine, and the demand for ultrafine silver powder is also increasing. increase. At present, the silver powder produced by domestic enterprises has problems of uneven particle size and particle agglomeration, and the silver powder required for the produc...

AI Technical Summary

Problems solved by technology

The patent publication number that Japan's Mitsui Metal Mining Co., Ltd. applied for is that the used dispersant of the preparation method of CN 1925941A is polyvinylpyrrolidone or gelatin, and wherein the optimum consumption of polyvinylpyrrolidone is 20%~40% of silver nitrate quality, uses The amount is very large, the cost is high, and the solubility of polyvinylpyrrolidone is not good, which has a great influence on the subsequent washing steps. When gelatin is used as the dispersant, the required temperature is high, the solubility is poor, and there is a certain impact on the production equipment. requirements, undoubtedly increasing production costs

The patent publication number is that the used dispersant of the preparation method of CN 101342596A is organic acid including oleic acid, stearic acid etc., these dispersants are very poor in water solubility, and wherein oleic acid is easily adsorbed on the silver powder surface of generation, is difficult for washing, has increased production cost and production cycle

Frequently used dispersants include sodium dodecylbenzenesulfonate, polyethylene glycol, Span series, Tween series, cetyltrimethylammonium bromide, etc., which are very important for controlling the particle size and morphology of silver powder. Unsatisfactory results