Silver Molecular Ink Low Viscosity Sintering

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Solution Overview

Problem

Current silver neodecanoate inks have low solubility issues leading to thin silver deposits and high viscosity, requiring multiple layers for thick traces, and high processing temperatures, which are costly and time-consuming, limiting their application in various printing techniques and substrates.

Innovation Solution

A molecular silver ink formulation with a silver carboxylate loading of 23 wt% or more, combined with an organic amine and a polymeric binder, achieving lower viscosity and lower processing temperatures, allowing for higher silver content and improved print quality at reduced thermal sintering temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If silver neodecanoate is diluted to form a uniform ink, then solubility and uniformity are improved, but silver loading decreases and viscosity increases

Engineering Contradiction:
ImproveuniformityVSAvoidsilver loading
Core Design Contradiction:
Stability of the object's compositionVSQuantity of substance

Solution Approach 1:

The patent changes the chemical parameters of the ink formulation by introducing specific solvents (ethanolamine, isopropanolamine) and polymeric binders (PVP, polyesters) to improve silver salt solubility without requiring excessive dilution. This allows maintaining high silver loading (30-40 wt%) while achieving uniform ink composition through enhanced molecular-level dissolution.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If silver neodecanoate ink is diluted to reduce viscosity, then viscosity decreases and printability is improved, but silver loading decreases and deposit thickness reduces

Engineering Contradiction:
ImproveprintabilityVSAvoidsilver loading
Core Design Contradiction:
Ease of operationVSQuantity of substance

Solution Approach 1:

The patent creates a composite ink system combining silver neodecanoate with multiple functional components: ethanolamine/isopropanolamine as solvents and chelating agents, PVP as a polymeric binder, and additional polyesters. This composite formulation achieves low viscosity for excellent printability while maintaining high silver loading (30-40 wt%) through synergistic interactions between components.

Inventive Principle:
Principle #40Composite materials

3Quantity of substance

If multiple layers are printed to achieve thick silver traces, then deposit thickness is improved, but processing time increases and print quality deteriorates

Engineering Contradiction:
Improvedeposit thicknessVSAvoidprocessing time
Core Design Contradiction:
Quantity of substanceVSLoss of time

Solution Approach 1:

The patent modifies the ink's physical parameters by formulating it with low viscosity through the addition of ethanolamine/isopropanolamine and polymeric binders. This enables single-pass printing to achieve thick silver deposits (up to 10 micrometers) without requiring multiple layer applications, thereby reducing processing time and improving print quality consistency.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If high processing temperature is used for sintering, then silver sintering is achieved, but substrate cost increases and thermal damage risk increases

Engineering Contradiction:
Improvesintering completionVSAvoidprocessing temperature
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent changes the thermal parameters of the ink formulation by incorporating ethanolamine or isopropanolamine which decompose at lower temperatures (190-220°C), and polymeric binders that facilitate sintering at reduced temperatures. This enables complete silver sintering and conductivity achievement at lower processing temperatures (150-200°C), reducing substrate cost requirements and minimizing thermal damage risk to temperature-sensitive substrates.

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 ink achieves higher silver loading and lower processing temperatures, enabling the production of conductive silver traces with improved conductivity and flexibility, suitable for diverse printing techniques and substrates, including those at lower cost, with reduced substrate damage.

Implementation Method 1

a polymeric binder comprising a polyester, polyimide, polyether imide or any mixture thereof having functional groups which are polar groups capable of participating in hydrogen bonding that render the polymeric binder compatible with the organic amine

Methodology Applied
Scientific EffectHydrogen bonding: Chemical Bonding

Implementation Method 2

sintering the non-conductive trace of the ink on the substrate to form the conductive silver trace

Methodology Applied
Scientific EffectSintering: Sintering

Data Source

PatentEP3580285B1Silver molecular ink with low viscosity and low processing temperature
Publication Date: 2024.02.21 E2IP TECH INC
  • EP3580285B1 patent drawingFigure 1A~1B
  • EP3580285B1 patent drawingFigure 2
  • EP3580285B1 patent drawingFigure 3

AI summary

A molecular ink contains: a silver carboxylate; and a polymeric binder comprising a polyester, polyimide, polyether imide or any mixture thereof having functional groups that render the polymeric binder compatible with the organic amine. Such an ink may have higher silver loading, lower viscosity and lower processing temperatures than existing silver inks.