Zero-Halogen Flame-Retardant PET Compound with Coupling Agent
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Solution Overview
Problem
Current halogen-free flame-retardant poly(ethylene terephthalate) (FR-PET) materials fail to meet stringent flame test requirements due to prolonged burn time, flame spread, and emission of flaming drips, and are prone to degradation when exposed to heat, especially in the presence of moisture, limiting their effectiveness in thermoplastics and polyesters.
Innovation Solution
A zero-halogen flame-retardant compound comprising poly(ethylene terephthalate) (PET), melamine cyanurate (MC), melamine polyphosphate (MPP), and an organo titanate coupling agent, which allows for extrusion of thin films, sheets, and yarns while maintaining thermal stability and preventing PET degradation, by using fine powders with controlled moisture and particle sizes, and a coupling agent that facilitates dispersion and reduces compounding temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If phosphorus-containing flame retardant compounds are added to PET during polycondensation, then flame-retardant properties are improved, but the material fails to meet stringent flame test requirements and exhibits prolonged burn time and flame spread
Solution Approach 1:
The patent uses a composite flame retardant system combining melamine cyanurate (MC) with phosphorus-containing compounds (ammonium polyphosphate, melamine phosphates, or phosphoric acid derivatives) in PET. This composite approach synergistically improves flame retardancy while controlling burn characteristics, achieving both MC's intumescent effect and phosphorus compounds' flame inhibition without the drawbacks of single-system FR-PET
Solution Approach 2:
The patent modifies the flame retardant mechanism by changing the chemical parameters of the FR system - specifically using nitrogen-containing melamine cyanurate in combination with phosphorus compounds, rather than relying on phosphorus alone. This parameter change enables the material to meet stringent flame tests by altering the decomposition and flame suppression chemistry
2Productivity
If compounding temperature is increased to process PET, then manufacturing efficiency is improved, but PET degradation occurs especially in the presence of moisture
Solution Approach 1:
The patent introduces an intermediary moisture control system using desiccants or moisture absorbers in the compounding process. This intermediary substance removes moisture from the PET and processing environment, allowing higher compounding temperatures to be used without causing PET degradation, thus resolving the conflict between processing efficiency and material stability
3Object-affected harmful factors
If halogen-free flame retardant systems are used, then environmental safety is improved, but the material emits flaming drips and fails UL VW-1 flame test
Solution Approach 1:
The patent converts the potential harm of flaming drips into a benefit by using phosphorus-containing flame retardants that promote char formation and melt drip suppression. The phosphorus compounds modify the melting behavior of PET, creating a protective char layer that prevents dripping while maintaining the halogen-free, environmentally safe composition
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 compound achieves excellent flame-retardant properties, meeting stringent flame test requirements, such as UL94 and FAR, with reduced degradation and emission of toxic smoke, and maintains tensile strength and low smoke density, suitable for various industries including aerospace and automotive.
Implementation Method 1
The coupling agent not only acts as a dispersion agent to the fine powders of PET, MC and MPP
Implementation Method 2
melamine cyanurate (MC) and melamine polyphosphate (MPP)... excellent flame-retardant properties
Implementation Method 3
The MC decomposes into melamine and cyanuric acid, while the MPP decomposes into melamine and phosphoric acid
Implementation Method 4
The compound can be extruded as a thin film or sheet or tubing, and also as a filament or yarn
Data Source
AI summary
A zero-halogen flame-retardant compound and continuous materials extruded therefrom comprise poly(ethylene terephthalate) (PET), fire-retardant ingredients melamine cyanurate (MC) and melamine polyphosphate (MPP), and an organo titanate coupling agent. The coupling agent acts as a dispersion agent to the fine powders of PET, MC and MPP and also allows the resin of the fine powders to be compounded at a reduced temperature which prevents degradation of the PET. The compound can be extruded as a thin film, sheet or tubing, and also as a filament or yarn, including monofilaments and multifilaments, which can ultimately be used to construct a protective sleeve.