Silver Nanoparticle Dispersion Liquid Low-Temperature Sintering

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Solution Overview

Problem

Silver nanoparticles used in electronic devices face challenges in achieving low-temperature and short-time calcining for conductivity while maintaining stability and surface smoothness, as existing methods struggle with agglomeration and incomplete sintering due to organic stabilizers.

Innovation Solution

A dispersion liquid containing silver nanoparticles is produced by mixing a silver compound with aliphatic amine compounds having specific carbon chain lengths, followed by thermal decomposition and dispersion in a solvent mixture of 50-90% alcohol-based and 10-50% aliphatic hydrocarbon-based solvents, allowing for effective sintering and surface coating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If silver nanoparticles are coated with organic stabilizers to maintain stability, then dispersion stability is improved, but sintering completeness deteriorates at low temperatures

Engineering Contradiction:
Improvedispersion stabilityVSAvoidsintering completeness
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent extracts and removes the organic stabilizer coating from the silver nanoparticles through thermal decomposition at low temperatures (80-150°C). This extraction process eliminates the barrier that prevents sintering, allowing the silver particles to fuse completely while the stabilizer decomposes and volatilizes, resolving the contradiction between maintaining dispersion stability and achieving sintering completeness

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the thermal parameters (temperature and time) to enable selective removal of the organic stabilizer. By controlling the heating process at specific low temperatures, the organic coating decomposes and evaporates, transforming from a stabilizing layer into a removed component, thus enabling complete sintering without requiring high temperatures that would damage the substrate

Inventive Principle:
Principle #35Parameter changes

2Reliability

If calcining temperature is increased to achieve complete sintering, then conductivity is improved, but substrate heat resistance requirement worsens

Engineering Contradiction:
Improvesintering completenessVSAvoidsubstrate heat resistance
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent applies preliminary action by first forming a uniform silver nanoparticle coating on the substrate, then using a controlled thermal decomposition process to remove the organic stabilizer and enable sintering. This preliminary preparation allows the sintering process to occur at lower temperatures than conventional methods, accommodating heat-sensitive substrates while still achieving complete sintering and excellent conductivity

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent fundamentally changes the temperature parameter from conventional high-temperature sintering (requiring substrates to withstand 200°C or higher) to low-temperature thermal decomposition (80-150°C). This parameter change enables complete sintering of silver nanoparticles on heat-sensitive plastic substrates without compromising substrate integrity

Inventive Principle:
Principle #35Parameter changes

3Reliability

If calcining time is extended to improve sintering completeness, then conductivity is improved, but production efficiency deteriorates

Engineering Contradiction:
Improvesintering completenessVSAvoidproduction efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent changes both temperature and time parameters of the thermal decomposition process. By operating at optimized low temperatures (80-150°C) for controlled durations, the process achieves complete sintering and stabilizer removal in a time frame that balances sintering completeness with production efficiency, avoiding both insufficient sintering and excessive processing time

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

This method enables silver nanoparticles to achieve excellent conductivity and surface smoothness at low temperatures, suitable for various electronic applications, including ink-jet printing, without clogging issues and requiring minimal post-calcining smoothing.

Implementation Method 1

thermally decomposing the complex compound by heating to form silver nano-particles

Methodology Applied
Scientific EffectThermal decomposition: Thermolysis

Implementation Method 2

silver nano-particles can be sintered even at a low temperature. Utilizing this property, a silver coating composition containing silver nano-particles is used to form electrodes or conductive circuit patterns

Methodology Applied
Scientific EffectSintering: Sintering

Data Source

PatentEP3369501B1Method for producing dispersion liquid containing silver nanoparticles, and dispersion liquid containing silver nanoparticles
Publication Date: 2020.02.26 DAICEL CORP
  • EP3369501B1 patent drawingFigure 1
  • EP3369501B1 patent drawingFigure 2
  • EP3369501B1 patent drawingFigure 3

AI summary

The present invention provides a dispersion liquid containing silver nano-particles that develops excellent conductivity by low-temperature calcining and has silver nano-particles stably and well dispersed in a dispersion solvent, and a method for producing the dispersion liquid containing silver nano-particles. [solution] A method for producing a dispersion liquid containing silver nano-particles, comprising: mixing a silver compound with amines comprising an aliphatic monoamine (A) comprising an aliphatic hydrocarbon group and one amino group, said hydrocarbon group having 6 or more carbon atoms in total; and further comprising at least one of: an aliphatic monoamine (B) comprising an aliphatic hydrocarbon group and one amino group, said hydrocarbon group having 5 or less carbon atoms in total; and an aliphatic diamine (C) comprising an aliphatic hydrocarbon group and two amino groups, said hydrocarbon group having 8 or less carbon atoms in total; to form a complex compound comprising the silver compound and the amines; thermally decomposing the complex compound by heating to form silver nano-particles; and dispersing the silver nano-particles in a dispersion solvent containing an alcohol-based solvent and an aliphatic hydrocarbon-based solvent in a specific ratio.