Cross-linked Polycarbonate Flame Retardance
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Solution Overview
Problem
Conventional polycarbonate compositions fail to achieve UL 94 V0 and 5VA performance characteristics, especially in thin-walled applications, due to poor flame retardance and drippage issues, while maintaining necessary physical and mechanical properties.
Innovation Solution
A cross-linked polycarbonate composition derived from non-cross-linked polycarbonates with 0.5 mol% to 5 mol% endcap groups from monohydroxybenzophenone and a flame retardant, such as potassium perfluorobutane sulfonate, which achieves UL94 5VA rating at thicknesses of 1.5 mm or less without impact modifiers, brominated, or chlorinated flame retardants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polycarbonate compositions are used, then transparency and mechanical properties are maintained, but flame retardance and drippage resistance are insufficient especially in thin-walled applications
Solution Approach 1:
The patent changes the chemical composition parameters by incorporating specific flame retardant compounds (potassium perfluorobutane sulfonate and potassium diphenyl sulfone-3-sulfonate) at optimized concentrations (0.06-0.10 wt% and 0.08-0.12 wt% respectively) to achieve UL 94 V0 and 5VA ratings while maintaining transparency and mechanical properties in thin-walled applications
Solution Approach 2:
The patent creates a composite material system by combining polycarbonate resin with multiple flame retardant additives and processing aids, forming a multi-component composition that achieves synergistic flame retardance without compromising the base polymer's transparency and mechanical performance
2Reliability
If flame retardants are added to improve flame resistance, then UL 94 V0 and 5VA ratings are achieved, but transparency and mechanical properties may deteriorate
Solution Approach 1:
The patent optimizes the concentration parameters of flame retardants to extremely low levels (0.06-0.10 wt% for potassium perfluorobutane sulfonate, 0.08-0.12 wt% for potassium diphenyl sulfone-3-sulfonate) to achieve UL 94 V0 and 5VA ratings while minimizing impact on transparency and mechanical properties
Solution Approach 2:
The patent introduces processing aids as intermediary substances to facilitate the uniform dispersion of flame retardants at low concentrations, ensuring effective flame retardance while maintaining the mechanical integrity and transparency of the polycarbonate matrix
3Reliability
If brominated or chlorinated flame retardants are used, then flame resistance is improved, but environmental and safety concerns increase
Solution Approach 1:
The patent replaces harmful brominated and chlorinated flame retardants with environmentally benign alternatives (potassium perfluorobutane sulfonate and potassium diphenyl sulfone-3-sulfonate) that provide equivalent or superior flame retardance (UL 94 V0 and 5VA ratings) without the toxic byproducts and environmental persistence associated with traditional halogenated additives
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 composition exhibits improved flame retardance, transparency, and mechanical properties, including impact strength and ductility, while maintaining chemical resistance and weatherability, suitable for thin-walled articles.
Implementation Method 1
a cross-linked polycarbonate, the cross-linked polycarbonate derived from a non-cross-linked polycarbonate comprising 0.5 mol% to 5 mol% endcap groups that are derived from a monohydroxybenzophenone
Data Source
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Figure 3
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AI summary
Disclosed herein are compositions including a cross-linked polycarbonate. The cross-linked polycarbonate may be derived from a polycarbonate having about 0.5 mol% to about 5 mol% endcap groups derived from a monohydroxybenzophenone. A plaque including the composition can achieve a UL94 5VA rating. Also disclosed herein are articles including the compositions, methods of using the compositions, and processes for preparing the compositions.