Halogen-Free Polycarbonate Fire-Retardant Composition
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Solution Overview
Problem
Current polycarbonate compositions face challenges in achieving enhanced transparency and fire-retardance while being environmentally friendly, as existing additives like brominated and chlorinated compounds are prohibited, and phosphate additives compromise mechanical performance.
Innovation Solution
A halogen-free polycarbonate composition is developed, combining potassium diphenylsulfone sulfonate (KSS) with sodium salt of toluene sulfonic acid (NaTS) and optionally a siloxane oligomer, which provides improved fire-retardancy and transparency without halogen content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If phosphate additives are used to achieve fire-retardance, then flame resistance is improved, but mechanical performance deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters by using aromatic sulfone sulfonate and aromatic sulfonate additives instead of phosphate additives, achieving fire-retardance (UL 94 V0 rating) while maintaining mechanical properties such as impact strength and tensile strength
Solution Approach 2:
The patent creates a composite flame retardant system combining aromatic sulfone sulfonate and aromatic sulfonate additives with polycarbonate, achieving synergistic fire-retardance effects while preserving the base polymer's mechanical performance
2Reliability
If brominated and chlorinated flame retardants are used, then fire-retardance is improved, but environmental compliance worsens
Solution Approach 1:
The patent extracts and eliminates harmful halogen elements (bromine and chlorine) from the flame retardant composition, replacing them with halogen-free aromatic sulfone sulfonate and aromatic sulfonate additives that provide equivalent fire-retardance while achieving Blue Angel and other environmental compliance certifications
Solution Approach 2:
The patent converts the previously harmful halogen-based flame retardants into beneficial halogen-free alternatives that not only provide fire-retardance but also enable environmental compliance, turning a regulatory liability into a marketing advantage
3Device complexity
If KSS is used alone for fire-retardance, then simplicity is maintained, but fire-retardance performance is insufficient
Solution Approach 1:
The patent merges aromatic sulfone sulfonate and aromatic sulfonate additives in a synergistic combination, where the two components work together to achieve superior fire-retardance performance (UL 94 V0 at 3.0mm) that exceeds the sum of their individual effects, while maintaining a relatively simple two-component system
4Reliability
If conventional additives are used to achieve fire-retardance, then flame resistance is improved, but transparency worsens
Solution Approach 1:
The patent changes the optical parameters by using aromatic sulfone sulfonate and aromatic sulfonate additives that are optically transparent, achieving fire-retardance while maintaining high light transmittance and clarity, unlike many conventional flame retardants that cause haze or discoloration
Data Source
AI summary
A halogen-free polycarbonate composition is disclosed having improved fÊre-retardancy and/or transparency characteristics. The composition comprises a polycarbonate, and a synergic combination of an aromatic s?lfone sulfonate such as potassium diphenylsulfone sulfonate, an aromatic sulfonate such as sodium salt of toluene sulfonic acid, and optionally a siloxane oligomer. The polycarbonate composition is useful for manufacture of electronic and mechanical parts, among others.