Styrenic Block Copolymer Flame-Retardant Composition
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Solution Overview
Problem
Current flexible flame retardant elastomer compositions for wire and cable insulation lack a balance of high flame retardant performance, heat stability, and mechanical properties, failing to meet the requirements for consumer electronics and similar applications.
Innovation Solution
Development of halogen-free, flame-retardant compositions comprising a styrenic block copolymer, a low-melting phosphorus-based flame retardant, and a blend of solid intumescent phosphorus and nitrogen-containing phosphoric acid salts, such as melamine derivative and piperazine pyrophosphate, which synergistically enhance flame-retardant properties and provide good mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional flame retardant compositions are used, then flame retardant performance can be achieved, but heat stability and mechanical properties deteriorate
Solution Approach 1:
The patent uses a composite flame retardant system combining low-melting phosphorus-based flame retardant (e.g., bisphenol A diphosphate) with solid intumescent flame retardants (melamine derivative and piperazine pyrophosphate). This composite approach creates synergistic effects where the phosphorus-based component provides initial flame inhibition and the intumescent components form a protective char layer, achieving UL-62 VW-1 flame test passage while maintaining mechanical properties through balanced formulation at 25-40 wt% total flame retardant content.
Solution Approach 2:
The patent optimizes the melting temperature parameter of the phosphorus-based flame retardant to be no higher than 170°C, which allows it to melt and activate at appropriate temperatures during fire exposure to provide flame inhibition. This parameter control ensures the flame retardant activates before the polymer degradation temperature, providing heat stability while maintaining mechanical integrity at service temperatures.
2Reliability
If high loading of flame retardants is used, then flame retardant performance is improved, but flexibility and processing properties worsen
Solution Approach 1:
The patent controls the total flame retardant loading to be in the range of 25-40 wt% of the composition, with the low-melting phosphorus-based flame retardant at 5-20 wt% and solid intumescent flame retardants at 20-35 wt%. This parameter optimization ensures sufficient flame retardant performance (passing UL-62 VW-1) while maintaining flexibility by avoiding excessive loading that would overly stiffen the polymer matrix.
Solution Approach 2:
The composite flame retardant system uses the low-melting phosphorus-based flame retardant to provide liquid-phase flame inhibition at lower loadings, reducing the need for high loadings of solid intumescent flame retardants. This synergy allows achieving UL-62 VW-1 passage at 25-40 wt% total loading rather than requiring higher loadings, thereby maintaining flexibility and processing properties.
3Object-affected harmful factors
If halogen-free flame retardants are used, then environmental safety is improved, but flame retardant performance may worsen
Solution Approach 1:
The patent employs a composite halogen-free flame retardant system combining low-melting phosphorus-based flame retardants (e.g., bisphenol A diphosphate) with solid intumescent flame retardants (melamine derivative and piperazine pyrophosphate). This composite approach achieves synergistic flame inhibition mechanisms: phosphorus-based components promote char formation and inhibit flaming, while intumescent components expand to form insulating foam layers. The formulation achieves UL-62 VW-1 flame test passage without any halogenated compounds, ensuring environmental safety while maintaining high flame retardant performance.
Solution Approach 2:
The patent optimizes the ratio and loading of halogen-free flame retardant components, with phosphorus-based flame retardant at 5-20 wt% and solid intumescent flame retardants at 20-35 wt%, to achieve synergistic flame inhibition. This parameter optimization ensures that the halogen-free formulation achieves UL-62 VW-1 passage, matching or exceeding the performance of conventional halogenated systems while eliminating environmental and health concerns associated with halogens.
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 compositions pass the UL-62 VW-1 flame test, exhibit excellent mechanical properties, and are suitable for various applications, including wire and cable jacketing and insulation, with the styrenic block copolymer accounting for at least 40% of the polymer content and the flame retardants making up at least 25% of the composition.
Implementation Method 1
a low-melting, phosphorus-based flame retardant having a melting temperature no higher than 170 °C
Implementation Method 2
a blend of solid intumescent phosphorus and nitrogen-containing flame retardants
Data Source
AI summary
Halogen-free, flame-retardant thermoplastic compositions that include a styrenic block copolymer, a low-melting, phosphorus-based flame retardant having a melting temperature no higher than 170° C, and a blend of solid intumescent phosphorus and nitrogen-containing flame retardants. The blend of solid intumescent flame retardants include at least two phosphorous and nitrogen-containing phosphoric acid salts that synergistically enhance the flame-retardant properties of the compositions relative to compositions that include other flame-retardant packages.