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

A technology of methylolamine and amine compounds is applied in the field of preparation of spherical silver powder, which can solve the problems of large influence of washing steps, poor solubility, and difficulty in washing, and achieves easy control of morphology, simple operation, and small particle size of silver powder. Effect

Inactive Publication Date: 2011-04-20
SOUTHEAST UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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

Method used

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preparation example Construction

[0016] The preparation method of spherical silver powder using methylolamine condensate as dispersant comprises the following steps: 1. reacting amine compound with formaldehyde solution to prepare methylolamine condensate as dispersant; 2. preparing reducing agent and dispersant Mix the solution, adjust the pH value of the mixed solution of the reducing agent and the dispersant with ammonia water or nitric acid solution, add the silver nitrate solution to the mixed solution of the reducing agent and the dispersant while stirring, wait until the reaction is complete, let stand and filter , washing and drying to obtain ultrafine spherical silver powders with different particle sizes of 0.5 to 3 microns.

[0017] In the first step of the above method, the amine compounds include urea, ethylenediamine, 1.3-propylenediamine, 1.2-butanediamine, 1.3-cyclohexanediamine, 1.4-cyclohexanediamine, piperazine, Tetrahydropyrazole, tetrahydroimidazole, piperidine, melamine, and the molar ra...

Embodiment approach 1

[0022] First prepare the hydroxymethylamine condensate dispersant: get 4.5 grams of anhydrous ethylenediamine solution and dissolve it in 4.5 grams of deionized water, then take 25 grams of formaldehyde solution with a mass fraction of 37%, and add the formaldehyde solution to the In the ethylenediamine solution, the reaction was stopped after 2 hours, and it was used as a dispersant for later use.

[0023] Take 10 grams of silver nitrate and dissolve it in 100 milliliters of water as an oxidizing agent solution, weigh 6 grams of ascorbic acid and 16 milliliters of the above-mentioned dispersant and dissolve it in 100 milliliters of deionized water as a reducing agent solution, and adjust the composition of the reducing agent and the dispersing agent with 5% nitric acid solution The pH value of the mixed solution is 6.0. Slowly add the oxidizing agent solution to the reducing agent mixed solution under stirring conditions. The dropwise addition time is 4 minutes, and then stop ...

Embodiment approach 2

[0025] First prepare the hydroxymethylamine condensate dispersant: get 50 grams of formaldehyde solution with a mass fraction of 37%, adjust the pH value of the solution to 9.0 with 5% sodium hydroxide solution, add 9 grams of urea to the formaldehyde under stirring In the solution, the reaction was stopped after 1 hour, and it was used as a dispersant for subsequent use.

[0026] Get 10 grams of silver nitrate and dissolve it in 100 milliliters of water as the oxidizing agent solution, weigh 6 grams of ascorbic acid and 30 milliliters of the above-mentioned dispersant and dissolve it in 100 milliliters of deionized water, and use 5% ammonia solution to adjust the mixing solution composed of the reducing agent and the dispersant. The pH value is 4.0. Slowly add the oxidizing agent solution to the reducing agent mixed solution under stirring conditions. The dropwise addition time is 4 minutes, and then stop the reaction for 20 minutes. Let stand, filter, and wash with deionized ...

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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...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B22F9/24
Inventor 林保平杨臻荣唐霁楠
Owner SOUTHEAST UNIV
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