Fine Silver Particle Production via Aqueous Amine Reduction

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Solution Overview

Problem

Conventional methods for producing fine silver particles are costly and time-consuming, with high alcohol usage and long reaction times, limiting their efficiency and economic viability.

Innovation Solution

A method involving the use of an aliphatic amine with a carbon number of 6 or more as an organic protective material, a reducing agent, and a silver compound in water at a temperature of 10 to 50 °C to reduce the silver compound, forming fine silver particles with an average primary particle diameter of 10 to 500 nm, using inert gas stirring and specific molar ratios.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional methods using alcohol as solvent and primary amine with unsaturated bonds are employed to produce fine silver particles, then particle formation is achieved, but the reaction time becomes excessively long (5-6 hours) and costs increase

Engineering Contradiction:
Improveparticle size controlVSAvoidreaction time
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The invention changes the chemical parameters by selecting specific aliphatic amines (hexylamine, octylamine, oleylamine) with carbon numbers of 6 or more as protective materials, and using secondary or tertiary amines as reduction supporting agents. This parameter change enables the reaction to complete in 0.5-2 hours instead of 5-6 hours, significantly improving productivity while maintaining particle size control of 10-500 nm

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention replaces expensive alcohol solvents with water as the reaction medium, and uses readily available aliphatic amines as protective materials. This substitution reduces material costs and eliminates the need for expensive organic solvents, making the process more economically viable while achieving the same particle formation objective

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Manufacturing precision

If conventional methods using alcohol as solvent are used to produce fine silver particles, then particle formation is achieved, but the cost of production increases due to expensive solvent and long reaction time

Engineering Contradiction:
Improveparticle size controlVSAvoidproduction cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The invention changes the solvent parameter from alcohol to water, and selects aliphatic amines with carbon numbers of 6 or more as protective materials. These water-soluble or water-dispersible amines enable the reaction to proceed in aqueous medium, eliminating the need for expensive alcohol solvents and reducing production costs while maintaining particle size control

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention replaces expensive alcohol solvents with water, which is inexpensive and readily available. The use of common aliphatic amines as protective materials further reduces material costs. This substitution strategy significantly lowers production costs while achieving the desired particle formation and size control

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Manufacturing precision

If conventional methods are used to produce fine silver particles, then particle formation is achieved, but organic waste is generated due to alcohol solvent usage

Engineering Contradiction:
Improveparticle size controlVSAvoidorganic waste
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The invention changes the solvent parameter from organic alcohol to water, creating an aqueous reaction system. The use of water-soluble or water-dispersible aliphatic amines as protective materials ensures all reaction components are water-based, eliminating organic waste generation while maintaining particle size control of 10-500 nm

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention converts the traditionally harmful organic alcohol solvent into beneficial water, which is environmentally friendly and non-toxic. By using water as the reaction medium and water-soluble amines as protective materials, the process eliminates organic waste and creates an environmentally benign production system that maintains manufacturing precision

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This method allows for the inexpensive and rapid production of fine silver particles, reducing reaction time to under 30 minutes and minimizing organic waste, while maintaining particle shape and size control.

Implementation Method 1

carrying out a reduction treatment of the silver compound to form fine silver particles

Methodology Applied
Scientific EffectReduction: Reduction

Implementation Method 2

an aliphatic amine having a carbon number of not less than 6 serving as an organic protective material

Methodology Applied
Scientific EffectAdsorption: Adsorption

Data Source

PatentEP2902138B1Method for producing fine silver particles
Publication Date: 2020.12.09 DOWA ELECTRONICS MATERIALS CO LTD
  • EP2902138B1 patent drawingFigure 1~2
  • EP2902138B1 patent drawingFigure 3~4
  • EP2902138B1 patent drawingFigure 5~6

AI summary

An aliphatic amine having a carbon number of not less than 6, such as octylamine, hexylamine or oleylamine, serving as an organic protective material is added to water serving as a solvent so that the molar ratio of the aliphatic amine with respect to silver of a silver compound is in the range of 0.05 to 6, a reducing agent, such as hydrazine or NaBH4, being added thereto so that the molar ratio of the reducing agent with respect to silver of the silver compound is in the range of 1 to 6, and the silver compound, such as a silver salt or a silver oxide, being added thereto so that the concentration of silver ions in the aqueous reaction solution is in the range of 0.01 to 1.0 mol/L, and then, the silver compound is reduced at a temperature of 10 to 50 °C to produce fine silver particles having an average primary particle diameter of 10 to 200 nm. Thus, there is provided a method for producing fine silver particles, the method being capable of inexpensively producing fine silver particles in a short time.