Expandable Graphite Textile Coating for Heat-Protective Clothing

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Solution Overview

Problem

Current flame protective clothing for firefighters and industrial workers faces challenges in providing adequate thermal insulation without increasing heat stress, as thicker insulation layers often lead to higher weight and reduced breathability, compromising performance in high-heat environments.

Innovation Solution

A polymer resin-expandable graphite mixture is applied to a flame-resistant, thermally stable textile in a discontinuous pattern to enhance thermal protective performance (TPP) while maintaining comfort and flexibility, with the mixture expanding by at least 200% after exposure to 300°C, thereby increasing TPP by at least 2 cal/cm² without significantly increasing weight or reducing breathability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If thicker insulation layers are added to increase thermal protection, then thermal protective performance (TPP) is improved, but heat stress burden increases and breathability is reduced

Engineering Contradiction:
Improvethermal protective performanceVSAvoidheat stress burden
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The expandable graphite undergoes a phase transition from a compact state to an expanded state when exposed to heat, creating an insulating barrier that protects the wearer from thermal radiation and convective heat transfer without requiring thick pre-compression insulation layers

Inventive Principle:
Principle #36Phase transitions

Solution Approach 2:

The expandable graphite material expands dramatically (up to 95 times its original volume) when heated, forming a low-density thermal barrier that provides high thermal protection while maintaining breathability and reducing heat stress burden compared to traditional thick insulation

Inventive Principle:
Principle #37Thermal expansion

2Reliability

If thicker insulation layers are added to increase thermal protection, then thermal protective performance (TPP) is improved, but garment weight increases

Engineering Contradiction:
Improvethermal protective performanceVSAvoidgarment weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The insulation material transitions from a compact low-weight state during normal wear to an expanded high-protection state when exposed to fire or extreme heat, providing high thermal protection without the permanent weight penalty of thick insulation layers

Inventive Principle:
Principle #36Phase transitions

Solution Approach 2:

The system combines a thermally stable textile substrate with expandable graphite particles to create a composite material that provides both structural integrity and on-demand thermal protection, optimizing the weight-protection balance

Inventive Principle:
Principle #40Composite materials

3Reliability

If thicker insulation layers are added to increase thermal protection, then thermal protective performance (TPP) is improved, but breathability is reduced

Engineering Contradiction:
Improvethermal protective performanceVSAvoidbreathability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The expandable graphite creates a porous expanded structure that provides thermal barrier properties while maintaining micro-ventilation channels, allowing moisture vapor transmission and breathability even in the expanded protective state

Inventive Principle:
Principle #36Phase transitions

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 significantly enhances thermal protective performance by increasing TPP while maintaining low thermal resistance, reducing heat stress, and ensuring breathability, thus improving the overall protective capabilities of the clothing without adverse effects on comfort or weight.

Implementation Method 1

the mixture expanding by at least 200% after exposure to 300°C

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

to provide suitable insulation (to reduce burn caused by heat transfer)

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP2664456B1Thermally protective materials
Publication Date: 2018.10.24 W L GORE & ASSOC GMBH
  • EP2664456B1 patent drawingFigure 1
  • EP2664456B1 patent drawingFigure 2
  • EP2664456B1 patent drawingFigure 3

AI summary

A mixture comprising an expandable graphite and a polymer resin is described wherein the polymer resin-expandable graphite mixture has a volume increase and structural integrity after exposure to heat. Methods are described for increasing the thermal protective performance (TPP) of of textiles and laminates while optionally maintaining comfort, flexibility, and liquid protective properties.