Conductive Ink Composition for High-Resolution Patterns

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Solution Overview

Problem

Existing conductive ink compositions require high firing temperatures and long times to achieve high-resolution conductive patterns, which is inefficient and can cause deformation in non-heat resistant substrates like PET films.

Innovation Solution

A conductive ink composition using a blocked polyisocyanate with an active methylene compound or pyrazole as a blocking agent and a reaction catalyst, combined with a conductive filler like silver powder and an epoxy compound, allows for lower temperature and shorter firing times, ensuring high-resolution and high-conductivity patterns without substrate deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional blocked polyisocyanate with MEK oxime blocking agent is used, then high conductivity can be achieved, but firing temperature must be high (150°C) and firing time must be long

Engineering Contradiction:
ImproveconductivityVSAvoidfiring temperature
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent changes the blocking agent from MEK oxime to 2,4-dinitrophenylhydrazine, which fundamentally alters the thermal dissociation characteristics of the blocked polyisocyanate. This parameter change enables the curing reaction to proceed at lower temperatures (80-120°C) while maintaining high conductivity, as the new blocking agent dissociates at lower temperatures to release the isocyanate groups needed for curing.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces a specific catalyst (organometallic catalyst such as dibutyltin dilaurate) as an intermediary to facilitate the curing reaction at lower temperatures. The catalyst mediates between the blocked polyisocyanate and the hydroxyl groups in the resin, enabling the curing process to occur efficiently at reduced temperatures and shorter times while achieving the desired conductivity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If conventional blocked polyisocyanate with MEK oxime blocking agent is used, then high conductivity can be achieved, but firing time must be long (30 minutes)

Engineering Contradiction:
ImproveconductivityVSAvoidfiring time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent changes the blocking agent from MEK oxime to 2,4-dinitrophenylhydrazine, which fundamentally alters the thermal dissociation characteristics of the blocked polyisocyanate. This parameter change enables the curing reaction to proceed at lower temperatures (80-120°C) while maintaining high conductivity, as the new blocking agent dissociates at lower temperatures to release the isocyanate groups needed for curing.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces a specific catalyst (organometallic catalyst such as dibutyltin dilaurate) as an intermediary to facilitate the curing reaction at lower temperatures. The catalyst mediates between the blocked polyisocyanate and the hydroxyl groups in the resin, enabling the curing process to occur efficiently at reduced temperatures and shorter times while achieving the desired conductivity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If high firing temperature and long firing time are used, then high conductivity pattern can be formed, but substrate deformation occurs in non-heat resistant materials like PET films

Engineering Contradiction:
ImproveconductivityVSAvoidsubstrate deformation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the blocking agent from MEK oxime to 2,4-dinitrophenylhydrazine, which fundamentally alters the thermal dissociation characteristics of the blocked polyisocyanate. This parameter change enables the curing reaction to proceed at lower temperatures (80-120°C) while maintaining high conductivity, as the new blocking agent dissociates at lower temperatures to release the isocyanate groups needed for curing.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces a specific catalyst (organometallic catalyst such as dibutyltin dilaurate) as an intermediary to facilitate the curing reaction at lower temperatures. The catalyst mediates between the blocked polyisocyanate and the hydroxyl groups in the resin, enabling the curing process to occur efficiently at reduced temperatures and shorter times while achieving the desired conductivity.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution enables the formation of high-resolution conductive patterns with high conductivity at lower temperatures and shorter times, maintaining substrate integrity, particularly on non-heat resistant materials like PET films, while improving productivity and reducing thermal deformation risks.

Implementation Method 1

a blocked polyisocyanate compound in which a blocking agent is an active methylene compound and/or a pyrazole compound

Methodology Applied
Scientific EffectThermal dissociation: Thermolysis

Implementation Method 2

a reaction catalyst for the blocked polyisocyanate

Methodology Applied
Scientific EffectCatalysis: Catalysis

Implementation Method 3

the content of this powder is 50 to 95 mass % relative to the entire amount of the electroconductive powder

Methodology Applied
Scientific EffectSintering: Sintering

Data Source

PatentUS10301488B2Conductive ink composition, method for producing conductive patterns, and conductive circuit
Publication Date: 2019.05.28 DIC CORP

AI summary

[Object] To provide a conductive ink composition which allows formation of a high resolution conductive pattern, and which can provide a high conductivity pattern by firing at a lower temperature and in a shorter time.[Solution] The aforementioned object is achieved by including a conductive filler, an epoxy compound, a blocked polyisocyanate in which a blocking agent is an active methylene compound and/or a pyrazole compound, a reaction catalyst for the blocked polyisocyanate, and an organic solvent as essential components. A conductive ink composition of the present invention can be fired at a lower temperature and in a shorter time and allows printing of a higher resolution conductive pattern.