Preparation method of silver powder for low-temperature conductive adhesive

A technology of conductive adhesive and silver powder, which is applied in the field of preparation of silver powder for low-temperature conductive adhesive, which can solve the problems of rising solution temperature, unfriendly environment, unfavorable scale-up production, etc., and achieve suitable particle size distribution, strong process controllability, and scale-up strong effect

Inactive Publication Date: 2019-02-15
西安宏星电子浆料科技股份有限公司
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  • Abstract
  • Description
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  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Chinese patent document CN105817644A discloses a method for preparing high-concentration ultra-fine silver powder. In this method, the oxidizing solution is configured into silver-ammonia solution. The silver-ammonia system is not friendly to the environment, has a pungent smell, and the waste water treatment cost is high, which is not conducive to scale-up. Production
[0004] Chinese patent document CN105345023B discloses a method for preparing ultra-fine silver powder with good dispersibility. Silver nitrate solution is mixed with hydrazine hydrate aqueous solution. This method is applied to ultrasonic crushing treatment equipment. This process requires strict control of ultrasonic time and intensity. Ultrasound will cause the temperature of the solution to rise rapidly, resulting in the agglomeration of ultra-fine silver powder, and insufficient ultrasound will fail to achieve the crushing effect
In addition, this process is not conducive to large-scale production

Method used

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  • Preparation method of silver powder for low-temperature conductive adhesive

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] (1) Dissolve 100kg of high-purity silver nitrate crystals with 500L deionized water to form a silver nitrate solution, add deionized water to make the total volume 1000L, and the concentration is 100g / L (calculated as elemental silver);

[0021] (2) Weigh 35kg of NaOH solid and dissolve it in deionized water to 350L, add 350L of sodium hydroxide solution prepared in (1), adjust the pH of the system to 11-12, heat the solution to 65°C, and stir well ;

[0022] (3) Measure 10L of 80% hydrazine hydrate (mass concentration) solution, dilute it to 18L with deionized water, add the diluted hydrazine hydrate solution to the solution of (2) above within 60 minutes under stirring conditions for reduction , after the addition is complete, continue to stir for 30 minutes;

[0023] (4) After the slurry is clarified, separate and remove the supernatant, add deionized water to wash the silver powder in the lower layer, and wash repeatedly 7 times until the conductivity is 12 μs / cm; ...

Embodiment 2

[0026] (1) Dissolve 100kg of high-purity silver nitrate crystals with 500L deionized water to form a silver nitrate solution, add deionized water to make the total volume 1000L, and the concentration is 100g / L (calculated as elemental silver);

[0027] (2) Weigh 72kg of ammonium carbonate solid, dissolve it in deionized water and fix it to 350L, add 350L of the prepared solution to (1) to adjust the pH of the system to 11-12 alkaline solution, so that the solution temperature is 36°C, Stir well;

[0028] (3) Measure 10L of 80% hydrazine hydrate (mass concentration) solution, dilute it to 18L with deionized water, add the diluted hydrazine hydrate solution to the solution of (2) above within 30 minutes under stirring conditions for reduction , after the addition is complete, continue to stir for 30 minutes;

[0029] (4) After the slurry is clarified, separate and remove the supernatant, add deionized water to wash the silver powder in the lower layer, and wash repeatedly 5 tim...

Embodiment 3

[0032] (1) Dissolve 100kg of high-purity silver nitrate crystals with 500L deionized water to form a silver nitrate solution, add deionized water to make the total volume 1000L, and the concentration is 100g / L (calculated as elemental silver);

[0033] (2) Weigh 72kg of NaOH solid and dissolve it in deionized water to 150L, ​​add 150L of sodium hydroxide solution prepared in (1) to adjust the pH of the system to an alkaline solution of 11-12, so that the solution temperature is 38°C , stir evenly;

[0034] (3) Weigh 8kg of glucose, dilute it to 50L with deionized water, add the diluted glucose solution to the solution of (2) above for reduction within 10 minutes under stirring conditions, and continue stirring for 30 minutes after the addition is complete ;

[0035] (4) After the slurry is clarified, separate and remove the supernatant, add deionized water to wash the silver powder in the lower layer, and wash repeatedly 6 times until the conductivity is 18μs / cm;

[0036] (5...

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Abstract

The invention discloses a preparation method of silver powder for a low-temperature conductive adhesive. At first, silver nitrate crystals are dissolved in deionized water, and the metallic silver concentration of solutions is adjusted to 50g/L-300g/L; then alkali solutions are added and stirred evenly, the pH of the solutions is adjusted to be equal to 8-14, the temperature of the solutions is adjusted to 30-70 DEG C, excessive reductant solutions are slowly dripped, and stirring continues after dripping is finished to obtain superfine silver slurry; and the superfine silver slurry is stilled, the lower layer silver powder is washed, additives are added and fully dispersed for 10 minutes, drying is conducted until the constant weight is reached, and the silver powder for the low-temperature conductive adhesive is obtained. The process amplification is high, the process controllability is high, and the process is environment-friendly. The obtained superfine silver powder has stable indicators, appropriate particle size distribution and good disperstiveness. The preparation method is suitable for low-temperature curing conductive paste.

Description

technical field [0001] The invention belongs to the field of silver powder preparation, and in particular relates to a method for preparing silver powder for low-temperature conductive adhesive. Background technique [0002] Silver powder is an important functional raw material in the electronics industry, and its preparation methods are divided into physical methods and chemical methods. At present, the chemical method is mainly used to prepare ultra-fine silver powder, and the industrial production is mainly based on the liquid phase reduction method. [0003] Chinese patent document CN105817644A discloses a method for preparing high-concentration ultra-fine silver powder. In this method, the oxidizing solution is configured into silver-ammonia solution. The silver-ammonia system is not friendly to the environment, has a pungent smell, and the waste water treatment cost is high, which is not conducive to scale-up. Production. [0004] Chinese patent document CN105345023B...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22F9/24
CPCB22F9/24
Inventor 王大林汪思敏吴高鹏高振威崔国强马倩刘丝颖张亚鹏殷美李艳
Owner 西安宏星电子浆料科技股份有限公司
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