Stretchable Conductive Paste With 3D Filler Network

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Solution Overview

Problem

Existing electrically conductive pastes are not stretchable due to high filler levels required for conductivity, limiting their extensibility.

Innovation Solution

A conductive paste comprising an elastic binder with a combination of conductive spherical, platelet-shaped, and rod-like fillers, allowing for high conductivity at low filler levels and high extensibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high filler levels are used to achieve sufficient conductivity, then electrical conductivity is improved, but extensibility deteriorates

Engineering Contradiction:
Improveelectrical conductivityVSAvoidextensibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent uses a composite filler system combining spherical, platelet-shaped, and rod-like conductive particles. This multi-morphology composite approach creates an efficient three-dimensional conductive network that achieves sufficient conductivity at lower overall filler levels (30-70 wt.%), thereby preserving the extensibility of the elastic binder (≥100% elongation).

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

Different filler morphologies serve specialized functions: spherical fillers provide conductivity and flow, platelet-shaped fillers create conductive planes, and rod-like fillers establish conductive bridges. This local functional differentiation optimizes the conductive network efficiency, reducing the total filler content needed while maintaining both conductivity and stretchability.

Inventive Principle:
Principle #3Local quality

2Reliability

If high filler levels are used to form sufficient conducting paths, then electrical conductivity is improved, but the maximum elongation is limited

Engineering Contradiction:
Improveelectrical conductivityVSAvoidmaximum elongation
Core Design Contradiction:
ReliabilityVSLength of moving object

Solution Approach 1:

The synergistic combination of three filler morphologies creates a percolation network that achieves conductivity thresholds at lower filler concentrations. This composite approach allows the elastic binder to maintain its extensibility (≥100% elongation) while still providing sufficient conductive pathways.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes the size parameters of different fillers (spherical: 0.5-10 μm, platelet: specific aspect ratios, rod-like: varying lengths) to maximize conductive network efficiency. By controlling particle size distributions and morphology parameters, the system achieves effective conductivity at reduced filler levels, preserving elongation capability.

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 paste maintains conductivity while being highly extensible, adapting to deformation without loss of conductivity due to a three-dimensional network formed by the fillers.

Implementation Method 1

The paste maintains conductivity while being highly extensible, adapting to deformation without loss of conductivity due to a three-dimensional network formed by the fillers

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP4114893B1Electrically conductive paste
Publication Date: 2025.09.03 CARL FREUDENBERG KG

AI summary

The invention relates to an electrically conductive paste comprising an elastic binder (A) and a conductive filler (B), the conductive filler (B) comprising the following components: at least one conductive filler (B1) in bead form, at least one conductive filler (B2) in flake form and at least one conductive filler (B3) in tube form.