Conductive Pattern Adhesion via Chemical Bonding Primer

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Solution Overview

Problem

Conductive ink does not adhere well to flexible substrates like polyimide resin, leading to separation and disconnection of electronic circuits, especially when bent, due to insufficient adhesion between the conductive ink and the substrate.

Innovation Solution

A conductive pattern is formed by creating a bond between a conductive layer containing a compound with a basic nitrogen atom-containing group and a primer layer containing a compound with a functional group, enhancing adhesion and maintaining electrical conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conductive ink is applied directly onto a substrate, then the manufacturing process is simple, but the adhesion between conductive ink and substrate is poor

Engineering Contradiction:
Improvesimplicity of manufacturing processVSAvoidadhesion between conductive ink and substrate
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent introduces a primer layer as an intermediary between the substrate and conductive ink. This primer layer contains functional groups that chemically bond with both the substrate and the conductive ink, thereby improving adhesion without significantly complicating the manufacturing process. The primer acts as a mediator that bridges the interface between substrate and conductive material.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs a composite structure consisting of substrate + primer layer + conductive ink layer. This multi-layer composite approach combines materials with different functions: the substrate provides mechanical support, the primer provides adhesion, and the conductive ink provides electrical conductivity. This composite structure resolves the adhesion problem while maintaining manufacturing feasibility.

Inventive Principle:
Principle #40Composite materials

2Reliability

If a latex layer is provided on the substrate to improve adhesion, then adhesion is enhanced, but the bond strength between latex layer and conductive ink is insufficient

Engineering Contradiction:
Improveadhesion between primer layer and conductive inkVSAvoidbond strength between latex layer and conductive ink
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent modifies the chemical parameters of the primer layer by selecting compounds with specific functional groups (carboxyl, hydroxyl, amino, epoxy, or isocyanate groups) that can form strong chemical bonds with the conductive ink. By changing the chemical composition and functional group types, the bond strength between the primer layer and conductive ink is significantly enhanced beyond what conventional latex layers can achieve.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If the substrate is made flexible (polyimide or polyethylene terephthalate resin), then the device can be bent, but the conductive ink easily separates from the substrate when bent

Engineering Contradiction:
Improveflexibility of substrateVSAvoidadhesion during bending
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The primer layer serves as a flexible intermediary that maintains strong adhesion between the flexible substrate and conductive ink during bending. The primer's chemical bonding capability ensures that the conductive ink remains attached to the substrate even when the flexible device is bent, preventing separation that would occur with direct application.

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

The conductive pattern achieves excellent adhesion and long-term electrical conductivity without disconnection, suitable for flexible electronic devices and applications like organic solar cells and RFID tags.

Implementation Method 1

a bond being formed by reacting the basic nitrogen atom-containing group of the compound (a1) contained in the conductive layer (A) with the functional group [X] of the compound (b1) contained in the primer layer (B)

Methodology Applied
Scientific EffectChemical Bonding: Chemical Bonding

Data Source

PatentEP2833705B1Electroconductive pattern, electric circuit, electromagnetic wave shield, and method for manufacturing electroconductive pattern
Publication Date: 2019.01.16 DIC CORP

AI summary

An object to be achieved by the present invention is to provide a conductive pattern having such a level of adhesion that a conductive layer containing a conductive substance such as silver does not separate from a primer layer with time. The present invention relates to a conductive pattern including a conductive layer (A) containing a compound (a1) having a basic nitrogen atom-containing group and a conductive substance (a2); a primer layer (B) containing a compound (b1) having a functional group [X]; and a substrate layer (C), the conductive layer (A), the primer layer (B), and the substrate layer (C) being stacked, in which a bond is formed by reacting the basic nitrogen atom-containing group of the compound (a1) contained in the conductive layer (A) with the functional group [X] of the compound (b1) contained in the primer layer (B).