Thermoplastic Polyurethane Flame Retardant Char Layer Formation
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Solution Overview
Problem
Thermoplastic polyurethane (TPU) materials used in cable sheaths tend to drip and ignite at high temperatures, compromising flame resistance and leading to rapid fire expansion, as existing flame-resistant additives are often inadequate at extremely high temperatures.
Innovation Solution
A formulation combining thermoplastic polyurethane with a flame retardant composition comprising metal or metalloid oxides, phosphate components, and oligomeric phosphate esters, which reduces dripping and enhances flame retardancy, particularly effective in UL VW-1 Vertical-Wire Flame Test applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional flame-resistant additives are used in TPU formulation, then flame resistance is improved, but at extremely high temperatures the additives become inadequate and burning material drips
Solution Approach 1:
The patent uses a composite flame retardant system combining three distinct components: metal/metalloid oxides (MgO, SiO2, Al2O3) that form stable char structures, phosphate components (APP, melamine phosphate) that provide intumescent behavior, and oligomeric phosphate esters that enhance char stability. This multi-component composite approach creates a synergistic effect where each component addresses specific limitations of conventional single-additive systems, preventing dripping at extremely high temperatures while maintaining flame resistance.
Solution Approach 2:
The patent optimizes the weight ratios of flame retardant components within specific ranges: metal/metalloid oxides (1-8%), phosphate components (25-85%), and oligomeric phosphate esters (10-70%). By carefully controlling these parameter ranges, the formulation achieves optimal char formation and stability characteristics that prevent dripping while maintaining effective flame retardancy across different temperature conditions.
2Reliability
If flame retardant composition is added to TPU formulation, then flame retardancy is enhanced, but the formulation complexity increases
Solution Approach 1:
The flame retardant composition serves multiple functions simultaneously: metal/metalloid oxides form protective char barriers, phosphate components provide intumescent swelling and acid release, and oligomeric phosphate esters enhance char stability and reduce dripping. This multi-functionality allows a single additive package to address flame retardancy, drip prevention, and thermal stability requirements, simplifying the overall formulation approach despite the multiple components involved.
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 formulation forms a stable char layer that prevents molten material from dripping, offering improved heat insulation and reducing the risk of fire acceleration, thereby enhancing flame retardancy and safety in wire and cable applications.
Implementation Method 1
The formulation forms a stable char layer that prevents molten material from dripping, offering improved heat insulation
Implementation Method 2
The formulation forms a stable char layer that prevents molten material from dripping, offering improved heat insulation
Implementation Method 3
at least one phosphate component selected from the group comprising ammonium polyphosphate (APP), melamine phosphate, melamine pyrophosphate and melamine polyphosphate
Data Source
AI summary
The present invention relates to a formulation comprising at least one thermoplastic polyurethane polymer and a flame retardant composition, the flame retardant composition comprising i) at least one metal or metalloid oxide particle selected from magnesium oxide, magnesium hydroxide, silicon oxide, or aluminium oxide; ii) at least one phosphate component selected from the group comprising ammonium polyphosphate (APP), melamine phosphate, melamine pyrophosphate and melamine polyphosphate or mixture thereof, and iii) at least one oligomeric phosphate ester.