Silver Ink Composition for Low-Temperature Conductive Traces

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Solution Overview

Problem

Current methods for forming metallic silver with sufficient electrical conductivity require high-temperature heat treatment, limiting the use of substrates and increasing production complexity, especially for communication devices where heat-resistant materials are not always necessary.

Innovation Solution

A silver ink composition comprising silver carboxylates, nitrogen-containing compounds, and reducing agents like oxalic acid or hydrazine, which allows for the formation of metallic silver at lower temperatures without heat treatment, enabling the use of non-heat-resistant substrates and expanding the range of applications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high-temperature heat treatment is used to form metallic silver with sufficient electrical conductivity, then electrical conductivity is improved, but substrate material selection is limited and production complexity increases

Engineering Contradiction:
Improveelectrical conductivityVSAvoidsubstrate material selection
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent changes the chemical parameters of the silver ink composition by incorporating specific organic compounds (silver carboxylates, amines, carboxylic acids) that enable silver metallization at lower temperatures. This parameter change allows the process to work with heat-sensitive substrates while maintaining sufficient electrical conductivity, thus resolving the contradiction between conductivity requirements and substrate material selection flexibility.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If high-temperature heat treatment is applied to form metallic silver, then sufficient electrical conductivity is achieved, but production complexity and restrictions increase

Engineering Contradiction:
Improveelectrical conductivityVSAvoidproduction process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent modifies the chemical composition parameters of the silver ink to include specific ratios of silver carboxylates, amines, and carboxylic acids. This compositional parameter change enables the metallization process to occur at reduced temperatures, thereby simplifying the production process and reducing equipment requirements while maintaining electrical conductivity performance.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If low silver concentration liquid composition is used, then application process is simpler, but sufficient electrical conductivity cannot be achieved

Engineering Contradiction:
Improveapplication process simplicityVSAvoidelectrical conductivity
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent creates a composite chemical system combining silver carboxylates with specific amines and carboxylic acids. This composite material approach enhances the reactivity and efficiency of the silver deposition process, allowing sufficient electrical conductivity to be achieved even at lower silver concentrations, thus maintaining application simplicity while meeting conductivity requirements.

Inventive Principle:
Principle #40Composite materials

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 silver ink composition achieves sufficient electrical conductivity at lower temperatures, facilitating the production of conductive materials and communication devices with improved design flexibility and reduced material constraints.

Implementation Method 1

one or more reducing compounds selected from the group consisting of oxalic acid, hydrazine and compounds represented by a general formula (5)

Methodology Applied
Scientific EffectChemical reduction: Reduction

Implementation Method 2

subjecting the resulting printed material to a heat (baking) treatment

Methodology Applied
Scientific EffectHeat treatment: Heat Treatment

Data Source

PatentUS10040960B2Silver ink composition, conductor and communication device
Publication Date: 2018.08.07 TOPPAN HOLDINGS INC

AI summary

There are provided a silver ink composition which is capable of forming metallic silver having sufficient electrical conductivity without carrying out a heat treatment at high temperatures; and a conductor and communication device which are obtained using this silver ink composition. Such a silver ink composition is characterized by being obtained by blending: a silver carboxylate having a group represented by a formula “—COOAg”; one or more nitrogen-containing compounds selected from the group consisting of amine compounds and quaternary ammonium salts of not more than 25 carbon atoms, ammonia, and ammonium salts obtained by reacting the above amine compounds or ammonia with an acid; and one or more reducing compounds selected from the group consisting of oxalic acid, hydrazine and compounds represented by a general formula (5) shown below (in the formula, R21 represents an alkyl group, alkoxy group or N,N-dialkylamino group of not more than 20 carbon atoms, a hydroxyl group or an amino group): or obtained by preparing a second mixture by supplying carbon dioxide to a first mixture formed by mixing a silver carboxylate having a group represented by a formula “—COOAg” and one or more nitrogen-containing compounds selected from the group consisting of amine compounds and quaternary ammonium salts of not more than 25 carbon atoms, ammonia, and ammonium salts obtained by reacting the amine compounds or ammonia with an acid; and further mixing one or more reducing compounds selected from the group consisting of oxalic acid, hydrazine and compounds represented by a general formula (5) shown below to the mixture: H—C(═O)—R21 (5).