Fine Silver Particle Dispersion Resistivity Stability

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Solution Overview

Problem

Fine silver particle dispersions face challenges in maintaining resistivity stability over time, which affects the performance of conductive thick films in electrical devices.

Innovation Solution

A fine silver particle dispersion comprising 60 to 95 wt.% fine silver particles with a particle diameter of 50 to 300 nm, 4.5 to 39 wt.% solvent, and 0.1 to 3 wt.% resin with a glass transition temperature of 70 to 300°C, where the particles are coated with an organic protective material like amine to prevent sintering, and the dispersion is formulated with specific solvents and resins to enhance stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If fine silver particles are dispersed in a solvent to form conductive thick films, then electrical conductivity is achieved, but resistivity stability deteriorates over time

Engineering Contradiction:
Improveresistivity stabilityVSAvoidpreservation period
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent introduces a specific resin as an intermediary substance between the fine silver particles and the solvent. This resin, with carefully controlled molecular weight (10,000-300,000) and glass transition temperature (70-300°C), acts as a stabilizing agent that prevents particle aggregation and maintains uniform dispersion over time, thereby ensuring resistivity stability during long-term preservation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies parameter changes by precisely controlling multiple parameters of the resin component including molecular weight range (10,000-300,000), glass transition temperature (70-300°C), and content ratio (0.1-3 wt%). By optimizing these parameters, the dispersion maintains its stability characteristics throughout the preservation period, preventing resistivity degradation.

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 dispersion provides preservation stability of resistivity, ensuring consistent performance of conductive thick films even after extended periods, as demonstrated by maintaining comparable resistivity values over 100 days.

Implementation Method 1

the particles are coated with an organic protective material like amine to prevent sintering

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 2

0.1 to 3 wt.% resin, wherein the glass transition temperature (Tg) of the resin is 70 to 300° C.

Methodology Applied
Scientific EffectGlass transition:

Data Source

PatentUS11441010B2Fine silver particle dispersion
Publication Date: 2022.09.13 DOWA ELECTRONICS MATERIALS CO LTD

AI summary

This disclosure relates to a fine silver particle dispersion comprising: (i) 60 to 95 wt. % of fine silver particles, wherein particle diameter (D50) of the fine silver particles is 50 to 300 nm, (ii) 4.5 to 39 wt. % of a solvent; and (iii) 0.1 to 3 wt. % of a resin, wherein the glass transition temperature (Tg) of the resin is 70 to 300° C., wherein the weight percentages are based on the weight of the fine silver particle dispersion.