Silver Paste Coated with Fatty Acid for Stable Polar Dispersion

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Solution Overview

Problem

Conventional conductive pastes using organic solvents for nano-sized metal particles face issues with ventilation requirements, combustion treatment, waste disposal, and unstable particle size, as well as poor redispersibility in polar solvents, which affect industrial productivity and environmental impact.

Innovation Solution

A composition of silver particles coated with a linear fatty acid, such as hexanoic acid, dispersed in a polar solvent like water or alcohol, which allows for stable existence and easy redispersion, enabling efficient production and use in electronic device applications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional conductive pastes using organic solvents are used, then the paste can be applied to form conductive patterns, but ventilation requirements, combustion treatment, and waste disposal issues arise due to organic solvent use

Engineering Contradiction:
Improveconductive paste applicationVSAvoidventilation requirements, combustion treatment, waste disposal
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent changes the solvent parameter from organic to polar (water-based), eliminating the need for ventilation, combustion treatment, and special waste disposal while maintaining paste applicability for conductive pattern formation

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses water as a replacement for expensive and hazardous organic solvents, creating a safer, more environmentally friendly conductive paste that does not require special handling infrastructure

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

2Manufacturing precision

If nano-sized metal particles are used to improve pattern precision and electrical conductivity, then fine line formation and conductivity improve, but particle size stability and redispersibility in polar solvents deteriorate

Engineering Contradiction:
Improvefine line formation precisionVSAvoidparticle size stability and redispersibility
Core Design Contradiction:
Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The patent introduces a polar solvent mediator that stabilizes nano-sized metal particles and enables their redispersibility, allowing fine line formation precision to be maintained while solving particle stability issues

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a composite conductive paste system combining nano-sized metal particles with polar solvent and appropriate additives, achieving both fine line precision and particle stability through material composition optimization

Inventive Principle:
Principle #40Composite materials

3Ease of operation

If conventional organic solvent-based conductive pastes are used, then the paste can be stored and applied, but poor redispersibility in polar solvents affects industrial productivity

Engineering Contradiction:
Improvepaste storage and applicationVSAvoidindustrial productivity due to poor redispersibility
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The patent changes the solvent system parameter to polar-based, fundamentally improving redispersibility and enabling better industrial productivity while maintaining ease of storage and application

Inventive Principle:
Principle #35Parameter changes

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

The composition provides fine silver particles with improved stability, redispersibility, and increased mass productivity, reducing environmental impact and operational costs while maintaining high electrical conductivity.

Implementation Method 1

the linear fatty acid adheres to the surface of the silver particles

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 2

metal fine particles formed by reduction of metal ions in an aqueous phase

Methodology Applied
Scientific EffectReduction: Reduction

Data Source

PatentEP2208559B1Silver microparticle-containing composition, process for production of the composition, process for production of the silver microparticle, and paste containing the silver microparticle
Publication Date: 2016.04.20 DOWA ELECTRONICS MATERIALS CO LTD
  • EP2208559B1 patent drawingFigure 1(a)~1(b)
  • EP2208559B1 patent drawingFigure 2(a)~2(b)
  • EP2208559B1 patent drawingFigure 3(a)~3(b)

AI summary

A composition containing fine silver particles which have a uniform particle size, can form a fine drawing pattern, and have a small environmental impact, a method for producing that composition, a method for producing fine silver particles, and a paste having fine silver particles are provided. The fine silver particles are produced by carrying out a fluid preparation step of preparing a reduction fluid, a silver reaction step, and a filtration/washing step. The reaction step is carried out by adding an aqueous silver nitrate fluid to a reduction fluid whose temperature has been increased to a range between 40 and 80°C. The aqueous silver nitrate fluid is added at a stretch. The composition containing fine silver particles is produced by dispersing the composition containing the fine silver particles in a polar fluid.