Silver Particle Coating Composition for Low-Temperature Conductivity

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Solution Overview

Problem

Silver nano-particles used in coating compositions for intaglio offset printing face challenges in achieving excellent conductivity and adhesion to substrates at low temperatures, as the organic stabilizers on their surfaces interfere with sintering and are poorly removed during low-temperature calcining, leading to inadequate conductive performance.

Innovation Solution

A silver particle coating composition comprising silver nano-particles coated with an aliphatic hydrocarbon amine protective agent and silver microparticles, where the short-chain amines facilitate efficient removal during low-temperature calcining, enhancing contact efficiency and adhesion, and including a binder resin, curable monomer, and polymerization initiator for improved substrate adhesion and flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If silver nano-particles with organic stabilizers are used, then particle stability and dispersion are improved, but sintering efficiency and conductivity are worsened due to interference during low-temperature calcining

Engineering Contradiction:
Improveparticle stabilityVSAvoidconductive performance
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent changes the chemical composition parameter of the protective agent from conventional organic stabilizers to specifically aliphatic hydrocarbon amines with 6-18 carbon atoms. This parameter change enables the protective agent to be effectively removed during low-temperature calcining (200°C or less), resolving the contradiction between maintaining particle stability during storage and achieving good sintering efficiency and conductivity after calcining.

Inventive Principle:
Principle #35Parameter changes

2Temperature

If low-temperature calcining is used for plastic substrates, then substrate heat resistance requirements are reduced, but organic stabilizer removal is insufficient leading to poor conductivity

Engineering Contradiction:
Improvecalcining temperatureVSAvoidconductive performance
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent modifies the chemical structure parameter of the protective agent to use aliphatic hydrocarbon amines with specific carbon chain lengths (6-18 atoms). This parameter change makes the protective agent thermally labile enough to be completely removed during low-temperature calcining (200°C or less), thereby achieving both low-temperature processing compatibility and excellent conductive performance after calcining.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent converts the potential harm of organic stabilizers interfering with sintering into a benefit by selecting aliphatic hydrocarbon amines that can serve dual functions: providing adequate particle stability during storage and application, while being easily removable during low-temperature calcining. The specific carbon chain length (6-18 atoms) optimizes this balance, transforming the stabilizer from a sintering obstacle into a controllable parameter for low-temperature processing.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Stability of the object's composition

If conventional organic stabilizers are used, then particle protection is improved, but adhesion to substrate and contact efficiency are worsened due to poor removal during calcining

Engineering Contradiction:
Improveparticle protectionVSAvoidcontact efficiency
Core Design Contradiction:
Stability of the object's compositionVSUse of energy by moving object

Solution Approach 1:

The patent changes the molecular structure parameter of the protective agent to aliphatic hydrocarbon amines with 6-18 carbon atoms. This parameter change provides adequate steric protection and colloidal stability during storage and application, while the moderate molecular weight and chemical structure enable complete removal during low-temperature calcining, thereby achieving excellent contact efficiency and adhesion to the substrate without leaving residual interference.

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 achieves excellent conductivity with low resistance values and improved adhesion to substrates, enabling successful printing on low-heat-resistant plastics like PET and polypropylene, while maintaining flexibility and transferability in intaglio offset printing.

Implementation Method 1

When the substrate is a plastic film or sheet, silver nano-particles need to be sintered at a low temperature (e.g., at 200°C or less) less than a heat resistant temperature of the plastic substrate

Methodology Applied
Scientific EffectThermal decomposition: Pyrolysis

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 on a substrate

Methodology Applied
Scientific EffectSintering: Sintering

Data Source

PatentEP3135405B1Silver particle coating composition
Publication Date: 2022.07.20 DAICEL CORP

AI summary

The present invention provides a silver particle coating composition that develops excellent conductivity by low-temperature and short-time calcining, and preferably achieves excellent adhesion between a silver coating film and a substrate. A silver particle coating composition comprising: silver nano-particles (N) whose surfaces are coated with a protective agent containing an aliphatic hydrocarbon amine; silver microparticles (M); and a dispersion solvent. The silver particle coating composition, further comprising a binder resin. The silver particle coating composition, further comprising a curable monomer and a polymerization initiator. The dispersion solvent comprises at least a glycol ester-based solvent. A silver coating composition that is suitable for intaglio offset printing.