Flame Resistant Polycarbonate Composition Reducing Smoke
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Solution Overview
Problem
Flame retardant polycarbonate compositions used in architectural and transportation applications often generate excessive smoke upon burning, which is a critical acceptance criterion that existing technologies have not adequately addressed.
Innovation Solution
A thermoplastic molding composition comprising 95 to 60 percent aromatic (co)polycarbonate, 5 to 40 percent bromine-substituted oligocarbonate, and 0.04 to 0.2 percent alkali or alkaline-earth salt of perfluoroalkane sulfonic acid, which significantly reduces smoke generation and flammability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If flame retardant polycarbonate compositions are used to improve flame retardance, then flammability is reduced, but smoke generation increases
Solution Approach 1:
The invention uses a composite formulation combining polycarbonate with bromine-substituted oligocarbonate and perfluoroalkane sulfonic acid salt. This composite approach allows the material to achieve both flame retardance and low smoke generation by leveraging the synergistic effects of multiple components working together, rather than relying on a single additive that would compromise one property for the other.
Solution Approach 2:
The invention optimizes specific parameters including the bromine content (5-40%), the amount of perfluoroalkane sulfonic acid salt (0.04-0.2%), and the molecular weight of the oligocarbonate. By precisely controlling these parameters, the composition achieves the optimal balance between flame retardance and smoke suppression, transforming the trade-off into a controlled optimization problem.
2Reliability
If bromine-substituted oligocarbonate is added to improve flame retardance, then flammability is reduced, but smoke generation increases
Solution Approach 1:
The perfluoroalkane sulfonic acid salt acts as an intermediary substance that mediates between the bromine-substituted oligocarbonate and the polycarbonate matrix. This intermediary component facilitates the decomposition pathway that produces water and carbon dioxide instead of smoke, enabling the bromine-containing additive to provide flame retardance without the harmful smoke generation that would otherwise occur.
3Object-generated harmful factors
If flame retardant additives are increased to suppress smoke, then smoke generation is reduced, but flammability resistance decreases
Solution Approach 1:
The invention demonstrates that excessive amounts of bromine-substituted oligocarbonate (beyond 5-40%) lead to poor flame retardance performance. By optimizing the parameter of additive concentration within this specific range, the composition achieves both smoke suppression and maintained flame retardance, proving that more additive is not always better and that an optimal point exists.
Data Source
AI summary
A thermoplastic molding composition that releases upon burning a limited amount of smoke is disclosed. The composition includes 95 to 60 percent aromatic (co)polycarbonate, 5 to 40 percent bromine-substituted oligocarbonate, and 0.04 to 0.2 percent alkali or alkaline-earth salt of perfluoroalkane sulfonic acid, the percents all occurrences being relative to the weight of the composition.