Interlayer Printing Process for Adhesion and Conductivity

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Solution Overview

Problem

Silver nanoparticle inks exhibit poor adhesion on substrates, particularly glass, which limits the robustness and mechanical properties of printed electronic devices, and adding polymeric materials to improve adhesion results in decreased conductivity.

Innovation Solution

A thermally curable interlayer composition is deposited on the substrate using aerosol printing, followed by heat treatment for curing, to enhance adhesion and create a smooth surface for conductive ink application, without compromising electrical conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If polymeric materials are added to conductive ink to improve adhesion, then adhesion is improved, but electrical conductivity decreases

Engineering Contradiction:
ImproveadhesionVSAvoidelectrical conductivity
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent divides the system into separate functional layers: a conductive ink layer for electrical conductivity and a polymeric interlayer for adhesion. The conductive ink is printed first, then a polymeric interlayer is applied over it, allowing each layer to perform its specialized function without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a polymeric interlayer as an intermediary between the substrate and the conductive ink. This interlayer acts as a mediator that enhances adhesion between the substrate and conductive features while maintaining the electrical conductivity of the metal traces through proper material selection and formulation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If conductive ink is printed directly on rough substrates, then manufacturing simplicity is maintained, but adhesion and surface quality deteriorate

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidadhesion
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent applies a polymeric interlayer to the substrate before printing the conductive ink. This preliminary action creates a smooth, adhesive surface that prepares the substrate for subsequent conductive ink deposition, improving both adhesion and surface quality without significantly complicating the manufacturing process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The polymeric interlayer serves as an intermediary between the rough substrate and the conductive ink, providing a smooth surface that enhances adhesion and facilitates proper conductive feature formation while maintaining manufacturing simplicity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If conductive ink is printed directly on rough substrates, then manufacturing simplicity is maintained, but surface smoothness deteriorates

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidsurface smoothness
Core Design Contradiction:
Ease of manufactureVSShape

Solution Approach 1:

The patent applies a polymeric interlayer to the substrate before printing the conductive ink. This preliminary action creates a smooth surface that enables proper conductive feature formation and encapsulation, achieving the desired surface quality without significantly complicating the manufacturing process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The polymeric interlayer acts as an intermediary that smooths the substrate surface, providing a uniform foundation for conductive ink deposition and subsequent encapsulation, thereby achieving good surface smoothness while maintaining manufacturing simplicity.

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 interlayer composition improves adhesion and conductivity of metal nanoparticle inks on various substrates, including 3D printed parts with rough surfaces, maintaining the electrical properties of the metal traces.

Implementation Method 1

A thermally curable interlayer composition is deposited on the substrate using aerosol printing

Methodology Applied
Scientific EffectAerosol: Aerosol

Implementation Method 2

followed by heat treatment for curing, to enhance adhesion

Methodology Applied
Scientific EffectHeat treatment: Heat Treatment

Implementation Method 3

to enhance adhesion and create a smooth surface for conductive ink application

Methodology Applied
Scientific EffectSurface smoothing:

Data Source

PatentEP3355668B1Interlayer printing process
Publication Date: 2022.12.14 XEROX CORP
  • EP3355668B1 patent drawingFigure 1a~1c
  • EP3355668B1 patent drawingFigure 1d~1e
  • EP3355668B1 patent drawingFigure 2

AI summary

Disclosed herein are a printing method and a printing system. The printing method includes providing a substrate and depositing an interlayer composition including a polymer selected from the group of epoxy resins, polyvinyl phenols and poly(melamine-co-formaldehyde) and an interlayer composition solvent on the substrate. The interlayer composition is cured to form a cured interlayer. A conductive metal ink composition is deposited on the cured interlayer and the conductive metal ink composition is cured to form a solid metal trace on the cured interlayer.