Thermoplastic Polyurethane Flame Retardant Composition
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Solution Overview
Problem
Thermoplastic polyurethane (TPU) compositions used in cable sheaths are prone to dripping and inadequate flame resistance at high temperatures, leading to rapid fire expansion, and existing solutions like irradiation crosslinking are costly and non-recyclable, while adding polysiloxane compromises fire retardancy.
Innovation Solution
A thermoplastic composition comprising TPU, modified polysiloxane in limited amounts (0.1-0.75% by weight) with functional groups, and conventional flame retardants, which forms a crusty layer preventing dripping and providing heat insulation during fires, while maintaining excellent flame retardancy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If irradiation crosslinking is used to prevent dripping, then flame resistance is improved, but production cost increases and recyclability is lost
Solution Approach 1:
The patent changes the chemical composition parameters by incorporating specific flame retardant additives (phosphorus-nitrogen compounds, metal hydroxides) and modifying the polymer structure with reactive silane groups, transforming the material from a simple TPU to a chemically modified composition that achieves flame resistance through controlled decomposition and char formation rather than crosslinking
Solution Approach 2:
The patent creates a composite material system combining TPU base polymer with multiple flame retardant additives (phosphorus-nitrogen compounds, metal hydroxides, synergistic agents) to achieve the desired flame resistance properties while maintaining thermoplastic processability and avoiding the need for crosslinking
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 effectively prevents molten material from dripping during fires, maintains high flame retardancy, and is cost-effective, passing stringent fire tests like UL VW-1, with improved processing characteristics and recyclability.
Implementation Method 1
forms a crusty layer preventing dripping and providing heat insulation during fires
Data Source
AI summary
Flame retardant thermoplastic composition comprising at least one thermoplastic polymer, preferably a thermoplastic polyurethane polymer, at least one conventional flame retardant and optionally at least one mineral filler together with modified polysiloxane in an amount of less than 1% by weight based on the total composition, preferably between 0.1 and 0.9% and most preferably between 0.25 and 0.75% by weight. The thermoplastic compositions are useful in applications where low flame properties are desirable, such as wire and cable applications.