Dendrite-Shaped Conductive Filler in Elastomer for Fatigue Resistance

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Solution Overview

Problem

Conventional extendable conductive films suffer from insufficient durability in maintaining conductivity during repeated extension and contraction, leading to an increase in resistance values.

Innovation Solution

A conductive sheet comprising a polyurethane-based elastomer with a dendrite-shaped conductive filler, where the filling factor of the filler is between 70 weight% and 95 weight%, ensuring improved contact between fillers and maintaining conductivity even during extension.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If flaky conductive filler is used to increase contact area, then conductivity before and after extension is improved, but durability during repeated extension and contraction is insufficient

Engineering Contradiction:
Improveconductivity maintenanceVSAvoiddurability during repeated extension and contraction
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent changes the geometric parameter of the conductive filler from flaky to dendrite-shaped, which fundamentally alters the contact mechanism. The dendrite shape with its branched structure provides multiple contact points along its length, maintaining conductivity through a different geometric configuration that is more resistant to separation during repeated extension and contraction cycles.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite material system combining polyurethane-based elastomer with dendrite-shaped conductive filler. This composite structure leverages the flexibility of the elastomer matrix and the conductive network of the dendrite filler, achieving both extendibility and durability through the synergistic combination of different material properties.

Inventive Principle:
Principle #40Composite materials

2Reliability

If filling factor of conductive filler is increased to improve conductivity, then resistance value decreases, but extendibility may be compromised

Engineering Contradiction:
ImproveconductivityVSAvoidextendibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent optimizes the filling factor parameter to a specific range (70-95 weight%) where the dendrite-shaped filler achieves optimal packing density. This parameter optimization ensures sufficient conductive pathways while leaving enough elastomer matrix to maintain flexibility and extendibility, resolving the trade-off between conductivity and adaptability.

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 solution effectively restrains the increase in resistance value during extension, providing a conductive composition with good resistance to fatigue and deterioration, achieving low resistance values even under repeated tensile strain.

Implementation Method 1

the contact between the conductive fillers can be maintained even during extension of the conductive film

Methodology Applied
Scientific EffectConduction (electrical): Conduction (electrical)

Implementation Method 2

a polyurethane-based elastomer; and a dendrite-shaped conductive filler filled in the polyurethane-based elastomer

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3196257B1Conductive composition and conductive sheet containing the same
Publication Date: 2022.09.21 TATSUTA ELECTRICWIRE & CABLE
  • EP3196257B1 patent drawingFigure 1~2A
  • EP3196257B1 patent drawingFigure 2B
  • EP3196257B1 patent drawingFigure 2C

AI summary

A conductive sheet 10 includes a peeling film 11 and a conductive film 12. The conductive film 12 is formed on one surface of the peeling film 11. The conductive film 12 is made of conductive composition. The conductive composition contains an elastomer and a dendrite-shaped conductive filler filled in the elastomer.