Flame-Retardant Thermoplastic Polyurethane for Cable Sheathing
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Solution Overview
Problem
Existing thermoplastic polyurethane compositions for cable sheathing lack adequate flame retardancy and mechanical properties, particularly for thin cables, as they either fail to pass stringent flame tests like UL 94V or have low Limiting Oxygen Index (LOI) values, which are essential for safety standards.
Innovation Solution
A composition combining thermoplastic polyurethane with melamine cyanurate and a combination of phosphorus-containing flame retardants, specifically phosphoric acid esters and phosphinates, where melamine cyanurate has a particle size of 0.1 to 100 μm, optimizing flame retardancy and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If halogen-free flame retardants are added to thermoplastic polyurethanes, then toxic smoke production is reduced, but flame retardancy is insufficient
Solution Approach 1:
The patent combines multiple flame retardant components (melamine cyanurate, phosphoric acid esters, and phosphinates) with thermoplastic polyurethane to create a composite material system. This composite approach allows the material to achieve both low smoke toxicity and adequate flame retardancy by leveraging the synergistic effects of different flame retardant mechanisms.
Solution Approach 2:
The patent optimizes the particle size of melamine cyanurate (0.1 to 100 μm) and carefully controls the ratios of phosphorus-containing flame retardants to achieve the desired balance between flame retardancy and smoke toxicity. By adjusting these parameters, the material meets both safety requirements.
2Length of moving object
If thin cable jackets are used to meet flame tests, then cable thickness is reduced, but mechanical properties deteriorate
Solution Approach 1:
The patent optimizes the particle size of melamine cyanurate (0.1 to 100 μm) to achieve effective flame retardancy in thin wall applications while maintaining mechanical integrity. The controlled particle size ensures proper distribution and effectiveness without compromising the structural properties of thin cable jackets.
Solution Approach 2:
The combination of multiple flame retardants with TPU creates a composite material that provides sufficient flame protection in thin sections while maintaining the mechanical strength required for cable applications.
3Reliability
If combinations of melamine cyanurate with phosphoric acid esters and phosphonic acid esters are used, then UL 94V test results improve, but LOI values decrease
Solution Approach 1:
The patent carefully controls the ratios and amounts of phosphoric acid esters and phosphinates to achieve the desired balance between UL 94V vertical burn resistance and LOI oxygen index values, optimizing the flame retardant system for cable applications.
Solution Approach 2:
The patent combines melamine cyanurate with a specific mixture of phosphoric acid esters and phosphinates to create a composite flame retardant system that achieves synergistic effects, improving both UL 94V ratings and maintaining adequate LOI values.
4Object-affected harmful factors
If combinations of melamine cyanurate with phosphinates are used, then LOI values increase, but UL 94V test results deteriorate
Solution Approach 1:
The patent combines phosphinates with phosphoric acid esters and melamine cyanurate to create a balanced composite flame retardant system that achieves both high LOI values and good UL 94V vertical burn resistance through synergistic interactions between components.
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 improved flame retardancy and mechanical properties, passing flame tests like VW1 and maintaining high LOI values, making it suitable for thin cable sheathing while reducing toxic smoke production.
Implementation Method 1
A composition combining thermoplastic polyurethane with melamine cyanurate and a combination of phosphorus-containing flame retardants, specifically phosphoric acid esters and phosphinates
Implementation Method 2
at least one first phosphorus-containing flame retardant (F1) selected from the group consisting of derivatives of phosphoric acid and derivatives of phosphonic acid and at least one further phosphorus-containing flame retardant (F2) selected from the group consisting of derivatives of phosphinic acid
Implementation Method 3
halogen-free flame-retardant thermoplastic polyurethanes generally have the advantage that they produce less toxic and less corrosive smoke gases when burned
Data Source
AI summary
The present invention relates to compositions containing at least one thermoplastic polyurethane, at least melamine cyanurate, at least one first phosphorus-containing flame retardant (F1) selected from the group consisting of derivatives of phosphoric acid and derivatives of phosphonic acid and at least one other phosphorus-containing flame retardant (F2) selected from the group consisting of derivatives of phosphinic acids, and to the use of a composition of this type for producing cable sheathing.