Brominated Polycarbonate Composition for Aircraft Smoke and Flame Control
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Solution Overview
Problem
Current thermoplastic polycarbonate compositions used in aircraft interiors face challenges in meeting both smoke density and flammability standards, as halogenated flame retardants like bromine improve flame spread but increase smoke generation, conflicting with safety requirements.
Innovation Solution
A thermoplastic polymer composition combining cyanophenyl endcapped polycarbonate, aromatic sulphone sulphonate, and brominated polycarbonate is developed, optimizing the amounts of these components to achieve both smoke density and flammability compliance, specifically using potassium diphenyl sulphon-3-sulphonate and varying bromine content to pass stringent tests like ASTM E662-06 and NF-P-92-505.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If halogenated flame retardants like brominated polycarbonate are used to improve flame spread resistance, then flammability performance is improved, but smoke density increases
Solution Approach 1:
The patent combines brominated polycarbonate (flame retardant) with cyanophenyl endcapped polycarbonate and aromatic sulphone sulphonate to create a composite material system. This composite approach allows the brominated component to provide flame spread resistance while the cyanophenyl endcapped polycarbonate suppresses smoke generation, achieving both flammability and smoke density requirements simultaneously
Solution Approach 2:
The patent optimizes the bromine content parameter within a specific range (0.26 wt.% to 5.2 wt.%) to balance flame retardancy and smoke generation. By precisely controlling this parameter and combining it with cyanophenyl endcapped polycarbonate, the material achieves NF-P-92-504 flame spread compliance while maintaining smoke density below 200 in ASTM E662-06 testing
2Reliability
If flame retardant additives are added to meet flammability standards, then flame spread resistance is improved, but burning drips may occur
Solution Approach 1:
The patent creates a composite system where brominated polycarbonate provides flame spread resistance while cyanophenyl endcapped polycarbonate suppresses dripping behavior. The synergistic interaction between these components allows the material to pass NF-P-92-505 drip testing without compromising flame retardancy
Solution Approach 2:
The aromatic sulphone sulphonate acts as an intermediary component that mediates between the flame retardant properties of brominated polycarbonate and the anti-drip properties of cyanophenyl endcapped polycarbonate, enabling the composite to achieve both flame spread and drip resistance
3Object-generated harmful factors
If smoke density is reduced to meet safety standards, then smoke generation is controlled, but flame retardancy may be compromised
Solution Approach 1:
The patent employs a composite material system where cyanophenyl endcapped polycarbonate serves as the smoke-suppressing matrix and brominated polycarbonate provides flame retardancy. This composite structure enables the material to achieve smoke density below 200 in ASTM E662-06 testing while simultaneously meeting NF-P-92-504 flame spread requirements
Solution Approach 2:
The patent utilizes specific parameter ranges for cyanophenyl endcapped polycarbonate and brominated polycarbonate to optimize the balance between smoke density and flame retardancy, achieving compliance with both ASTM E662-06 smoke density standards and NF-P-92-504 flame spread standards
Data Source
AI summary
A thermoplastic polymer composition comprises a cyanophenyl endcapped polycarbonate, a potassium diphenyl sulphon-3-sulphonate; and brominated polycarbonate. In some embodiments, when the thermoplastic polymer composition is in the form of a 3 mm thick extruded sheet, the sheet has a smoke density of less than 200 at an exposure period of 240 seconds in accordance with the smoke density test as set forth in ASTM E662-06, and has no burning drips on the sheet for a duration of 10 minutes in accordance with the flammability test as set forth in NF-P-92-505.