Recycled Polycarbonate Composition Balancing Flame Retardancy and Transparency
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Solution Overview
Problem
There is a need for a polycarbonate resin composition that is excellent in flame retardancy and transparency, particularly for formed articles, as existing compositions may not adequately address these requirements.
Innovation Solution
A resin composition comprising recycled polycarbonate resin, a flame retardant, and a specific molecular weight ratio between recycled and virgin polycarbonate resins, without the use of fluoropolymers, which includes a metal salt-based flame retardant, such as an alkali metal salt of sulfonic acid or a phosphazene compound.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fluoropolymers are used to achieve flame retardancy, then flame retardancy is improved, but transparency deteriorates
Solution Approach 1:
The invention removes fluoropolymers from the resin composition while maintaining flame retardancy through alternative mechanisms. The patent achieves this by using a specific combination of phosphorus-based flame retardant and antimony oxide, eliminating the need for fluoropolymer additives that compromise transparency.
Solution Approach 2:
The invention creates a composite flame retardant system combining phosphorus-based compounds and antimony oxide in specific ratios. This composite approach provides effective flame retardancy through synergistic effects without requiring fluoropolymer additives, thus maintaining the transparency of the polycarbonate resin.
2Adaptability or versatility
If recycled polycarbonate resin is used, then environmental sustainability is improved, but molecular weight consistency deteriorates
Solution Approach 1:
The invention controls the viscosity average molecular weight of the recycled polycarbonate resin within a specific range (5,000 to 50,000) to optimize both sustainability and performance. By specifying molecular weight parameters, the patent ensures consistent rheological properties and mechanical strength while utilizing recycled materials.
Solution Approach 2:
The invention applies different quality requirements to different components: recycled polycarbonate resin with controlled molecular weight for sustainability, virgin polycarbonate resin for base performance, and specific flame retardants for flame resistance. This differentiated approach allows each component to contribute optimally to the overall composition.
3Reliability
If flame retardant content is increased to improve flame retardancy, then flame retardancy is improved, but mechanical properties deteriorate
Solution Approach 1:
The invention optimizes the content of phosphorus-based flame retardant and antimony oxide within specific ranges to achieve effective flame retardancy while minimizing impact on mechanical properties. The patent specifies controlled amounts of each additive to balance flame resistance and structural integrity.
Solution Approach 2:
The invention uses antimony oxide as an intermediary that enhances the effectiveness of phosphorus-based flame retardants, allowing lower overall additive levels to achieve the same flame retardancy. This synergistic combination reduces the total amount of flame retardant needed, thereby preserving mechanical properties.
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 achieves excellent flame retardancy and transparency in formed articles by promoting the formation of a carbonized layer during combustion, reducing the need for anti-dripping agents, and enhancing heat resistance and toughness.
Implementation Method 1
promoting the formation of a carbonized layer during combustion
Data Source
AI summary
A resin composition comprises a polycarbonate resin and a flame retardant, wherein the polycarbonate resin comprises a recycled polycarbonate resin, wherein the resin composition is substantially free from fluoropolymers.