Textile Composite with Expandable Graphite Layer to Reduce Afterflame
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional flame-resistant protective garments for hazardous environments are often expensive, difficult to dye or print, lack abrasion resistance, and provide unsatisfactory tactile comfort, while also being impractical for occasional flash fire exposure due to high costs and limited breathability.
Innovation Solution
A flexible textile composite is developed, comprising a meltable, flammable outer textile layer combined with a thermally stable convective barrier and a heat reactive material layer made of a polymer resin-expandable graphite mixture, which reduces afterflame time and char length, and enhances breathability and comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional inherently flame resistant fibers (aramids, PBI, PBO) are used, then flame resistance is improved, but cost increases significantly
Solution Approach 1:
The patent applies composite materials by combining a flammable outer textile layer with a heat reactive material layer containing expandable graphite and polymer resin. This composite structure provides flame resistance through the heat reactive layer that expands and forms an insulating barrier when exposed to heat, rather than relying on inherently flame resistant fibers throughout the entire garment structure.
Solution Approach 2:
The patent applies local quality by concentrating the flame protective function in a specific heat reactive material layer applied to the inner surface of the outer textile. Only the areas exposed to flame contact receive this protective treatment, allowing the use of cheaper flammable outer materials while providing targeted flame resistance where needed.
2Reliability
If traditional inherently flame resistant fibers are used, then flame resistance is improved, but tactile comfort deteriorates
Solution Approach 1:
The protective heat reactive material is applied locally to the inner surface of the outer textile, allowing the outer fabric to maintain its desirable tactile properties while the inner heat reactive layer provides flame protection. This localized approach preserves the comfort benefits of materials like nylon or polyester in the areas contacting the skin.
3Reliability
If traditional inherently flame resistant fibers are used, then flame resistance is improved, but breathability deteriorates
Solution Approach 1:
The composite structure allows the outer textile to be made from breathable materials like nylon or polyester, while the heat reactive material layer provides flame protection. The heat reactive layer expands upon heating to create an insulating barrier that does not permanently block breathability under normal conditions.
4Quantity of substance
If flammable, meltable outer textile is used, then cost and comfort are improved, but flame resistance deteriorates
Solution Approach 1:
The heat reactive material is applied in advance to the inner surface of the outer textile to prevent flame propagation. When heat is applied, the heat reactive material expands and forms a protective barrier that prevents the flammable outer textile from igniting or sustaining combustion, thereby providing preliminary protection against flame.
Solution Approach 2:
The patent converts the harmful flammability of the outer textile into a benefit by using the melt behavior of the outer layer to trigger the heat reactive material. As the outer textile melts or degrades under heat exposure, it exposes and activates the heat reactive material layer, which then expands to provide protective char formation and insulation.
5Reliability
If heat reactive material is applied to reduce afterflame, then flame resistance is improved, but device complexity increases
Solution Approach 1:
The patent extracts the flame protective function from the bulk textile structure and concentrates it in a separate heat reactive material layer applied to the inner surface. This separation allows the outer textile to maintain its simple, comfortable structure while the extracted protective layer provides the necessary flame resistance.
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 composite achieves a significant reduction in afterflame time and char length, improved breathability, and increased comfort while maintaining flame resistance, making it suitable for hazardous environments without the high costs associated with traditional materials.
Implementation Method 1
the expandable graphite has an expansion of at least 900 μm upon heating to 280°C according to the Thermo-Mechanical Analysis (TMA) Expansion Test
Implementation Method 2
an endotherm of at least 100 J/g when measured according to the DSC Endotherm Test
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method is described for reducing the afterflame of a flammable, meltable material. A textile composite is described comprising an outer textile comprising a flammable, meltable material, and a continuous layer of heat reactive material comprising a polymer resin-expandable graphite mixture.