Thermoplastic Polyurethane with Spirocyclic Chain Extender
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Solution Overview
Problem
Current thermoplastic polyurethane (TPU) compositions lack sufficient heat resistance for applications in high-temperature environments, such as Class D type cables and systems requiring temperatures above 125 °C, while maintaining mechanical properties like tensile strength and elongation.
Innovation Solution
A TPU composition is developed through the reaction of an aromatic diisocyanate, an alkylene substituted spirocyclic compound, and a polycarbonate polyol, where the spirocyclic compound contains two rings with 5 to 7 atoms each, substituted with an alkylene group of 1 to 4 carbon atoms, terminated by a hydroxy group or primary/secondary amine, and processed into a hot extruded tube to enhance heat resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional TPU compositions are used, then mechanical properties like tensile strength and elongation are maintained, but heat resistance is insufficient for high-temperature environments above 125 °C
Solution Approach 1:
The patent modifies the chemical structure of the polyol component by introducing spirocyclic compounds with specific ring structures (5-7 atoms) and alkylene substitutions. This structural parameter change in the polymer backbone increases the glass transition temperature and thermal stability, enabling the TPU to maintain mechanical properties at temperatures above 125 °C while meeting Class D cable requirements
Solution Approach 2:
The invention creates a composite polymer system combining aromatic diisocyanate, spirocyclic polyol, and polycarbonate polyol in specific ratios. This composite material approach integrates the thermal stability of spirocyclic structures with the mechanical properties of polycarbonate polyol, achieving both heat resistance and maintained tensile strength/elongation at elevated temperatures
2Temperature
If TPU is designed for high heat resistance above 125 °C, then thermal stability improves, but mechanical properties like tensile strength and elongation may deteriorate
Solution Approach 1:
The patent introduces spirocyclic structures at specific locations within the polymer chain (as polyol components) rather than uniformly modifying the entire polymer structure. This localized structural modification provides thermal stability at critical points while preserving the overall mechanical integrity and flexibility of the TPU material
Solution Approach 2:
By carefully controlling the molecular weight, hydroxyl value, and structural parameters of the spirocyclic polyol and polycarbonate polyol components, the patent optimizes the balance between thermal stability and mechanical properties. The specific parameter ranges for the polyol components ensure heat resistance above 125 °C while maintaining adequate tensile strength and elongation
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 resulting TPU exhibits significant heat resistance improvements, performing well under short-term heat aging conditions exceeding 175 °C, maintaining mechanical properties and preventing thermal damage, as demonstrated by ISO 6722 Type D and UL1581 standards.
Implementation Method 1
reacting (1) an aromatic diisocyanate, (2) an alkylene substituted spirocyclic compound comprising an alkylene substituted saturated spirocyclic-diol, an alkylene substituted saturated spirocyclic-diamine, or a combination thereof, and (3) a polycarbonate polyol
Implementation Method 2
cooling the hot extruded tube to below the melting point of the thermoplastic polyurethane composition to produce an extruded thermoplastic polyurethane
Implementation Method 3
below the melting point of the thermoplastic polyurethane composition
Data Source
AI summary
The present invention relates to novel thermoplastic polyurethane (TPU) compositions that contain alkylene substituted spirocyclic compounds as chain extender and polycarbonate polyol. The present invention provides for TPUs which exhibit high temperature resistance.