Halogen-Free Fire Retardant Coating for Aircraft Interiors
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Solution Overview
Problem
Developing effective and environmentally friendly halogen-free fire retardant coatings for aircraft interior components that meet FAR 25.853 standards, particularly at film thicknesses below 200 microns, while maintaining aesthetics and mechanical properties, has been challenging due to the limitations of intumescent systems which are primarily used in structural applications and generate excessive smoke.
Innovation Solution
A halogen-free, non-intumescent fire retardant coating composition comprising a (meth)acrylate polymer with a glass transition temperature of at least 45°C, a polyurethane based on a polycarbonate polyol, and ammonium polyphosphate, applied in thin layers without a charring agent or blowing agent, and formulated as a waterborne or solventborne system to provide excellent fire retardant characteristics and long storage stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If intumescent systems are used for fire retardant coating, then fire resistance is improved, but film thickness must be greater than 200 microns and smoke generation increases
Solution Approach 1:
The invention changes the chemical composition parameters of the coating system by using a polyurethane based on polycarbonate polyol with specific glass transition temperature (at least 45°C) combined with ammonium polyphosphate, replacing the conventional intumescent formulation. This parameter change enables effective fire protection at reduced film thicknesses below 200 microns while maintaining aesthetic properties.
Solution Approach 2:
The invention creates a composite coating system combining polyurethane polymer matrix with ammonium polyphosphate fire retardant additives. This composite material approach provides both mechanical properties and fire protection in a single coating layer, eliminating the need for thick intumescent layers while achieving FAR 25.853 compliance.
2Reliability
If intumescent coatings are used, then fire protection is achieved, but smoke generation increases and aesthetics are compromised
Solution Approach 1:
The invention modifies the chemical parameters of the fire protection system by using halogen-free ammonium polyphosphate in a polyurethane matrix, changing the decomposition behavior and smoke generation characteristics. This results in reduced smoke and toxic fume production during fire exposure while maintaining fire protection performance.
Solution Approach 2:
The invention converts the potential harm of smoke generation into a benefit by selecting fire retardant additives that promote char formation with low smoke emission. The ammonium polyphosphate promotes protective char layer formation that suppresses both fire spread and smoke generation, turning the fire exposure scenario into a controlled process with minimal harmful emissions.
3Weight of moving object
If thin film thickness is used for weight constraints, then weight is reduced, but fire protection effectiveness decreases
Solution Approach 1:
The invention changes the functional parameters of the coating by incorporating high-performance fire retardant additives (ammonium polyphosphate) that are effective at low concentrations and thin film thicknesses. This enables achieving FAR 25.853 fire protection standards with coatings applied at 50-100 microns, significantly reducing weight compared to conventional thick intumescent coatings.
4Object-affected harmful factors
If halogen-free fire retardants are used, then environmental friendliness is improved, but achieving FAR 25.853 standards at thin film thicknesses becomes more difficult
Solution Approach 1:
The invention develops a composite coating formulation combining polyurethane polymer with ammonium polyphosphate fire retardant. This composite approach synergistically enhances fire protection performance while maintaining environmental friendliness through halogen-free composition, achieving both FAR 25.853 compliance and ecological safety.
Solution Approach 2:
The invention optimizes the concentration and distribution parameters of ammonium polyphosphate within the polyurethane matrix to maximize fire protection efficiency at thin film thicknesses. By carefully controlling the formulation parameters, the coating achieves effective fire retardancy with halogen-free additives, meeting both performance and environmental requirements.
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 coating composition meets the flammability and smoke density requirements of FAR 25.853, offers good mechanical and stain resistance, and is environmentally safe, with a low volatile organic content, allowing for application in thin layers without compromising performance, and demonstrating comparable heat release performance to halogen-based systems.
Implementation Method 1
a (meth)acrylate polymer, wherein the glass transition temperature Tg of the (meth)acrylate polymer is at least 45°C
Implementation Method 2
a polyurethane, wherein the polyurethane is based on a polycarbonate polyol
Implementation Method 3
ammonium polyphosphate
Data Source
AI summary
The invention relates to a halogen-free, non-intumescent, fire retardant coating composition comprising (a) a (meth)acrylate polymer, wherein the glass transition temperature (Tg) of the (meth)acrylate polymer is at least 45°C, measured with MDSC at 5°C/min as described in the description, (b) a polyurethane, wherein the polyurethane is based on a polycarbonate polyol, and (c) ammonium polyphosphate (APP). The coating compositions have a long storage stability and result in coatings with good fire retardant properties, mechanical strength and chemical and stain resistance. The coating composition contains only halogen-free fire retardants for environmental safety and toxicity reduction. The coating compositions can be used for various substrates including plastic, composite, metal substrates, and are especially suitable for cabin coatings.