Polycarbonate-Modified TPU for Heat- and Hydrolysis-Resistant Cable Sheathing

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Solution Overview

Problem

Current materials used for cable sheathing in automobile applications, such as ETFE and crosslinked polyolefin materials, fail to meet stringent requirements for high temperature resistance, hydrolysis resistance, and fire performance, particularly in electrical vehicles and hybrid vehicles, where they are exposed to higher temperatures and harsh conditions.

Innovation Solution

A thermoplastic polyurethane is produced through a process involving the reaction of a thermoplastic polyester with a diol and an isocyanate composition, including a polycarbonate polyol, to create a material with enhanced mechanical and hydrolysis resistance, which can be combined with flame retardants for improved performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If ETFE is used for cable sheathing in high temperature applications, then temperature resistance is improved, but corrosive gases are formed during fire

Engineering Contradiction:
Improvetemperature resistanceVSAvoidcorrosive gases during fire
Core Design Contradiction:
TemperatureVSObject-generated harmful factors

Solution Approach 1:

The patent uses a composite material system consisting of thermoplastic polyester, polycarbonate polyol, and polyisocyanate to create TPU with superior fire performance. This composite approach achieves both high temperature resistance (up to 150°C) and flame retardancy without generating corrosive gases, resolving the contradiction between temperature resistance and fire safety

Inventive Principle:
Principle #40Composite materials

2Temperature

If crosslinked compounded polyolefin materials are used, then temperature resistance is improved, but production complexity and cost increase

Engineering Contradiction:
Improvetemperature resistanceVSAvoidproduction complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent extracts the crosslinking step from the production process by using thermoplastic polyurethane that achieves high temperature resistance through its molecular structure and composition rather than through crosslinking. This eliminates the need for post-crosslinking by irradiation or vulcanization, significantly simplifying production while maintaining temperature resistance up to 150°C

Inventive Principle:
Principle #2Taking out (Extraction)

3Strength

If conventional thermoplastic polyurethanes are used, then mechanical properties are maintained, but hydrolysis resistance deteriorates under high temperature and humidity

Engineering Contradiction:
Improvemechanical propertiesVSAvoidhydrolysis resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters by incorporating polycarbonate polyol with specific molecular weight (500-4000) and using polyisocyanate in controlled ratios. This compositional parameter change provides both the desired mechanical properties and enhanced hydrolysis resistance, allowing the material to withstand 3000 hours at 85°C and 85% relative humidity while maintaining mechanical integrity

Inventive Principle:
Principle #35Parameter changes

4Temperature

If materials are selected to meet temperature class D requirements, then temperature resistance is improved, but hydrolysis resistance requirements become more stringent

Engineering Contradiction:
Improvetemperature resistanceVSAvoidhydrolysis resistance
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent employs a composite material system combining thermoplastic polyester, polycarbonate polyol, and polyisocyanate in specific proportions. This composite formulation simultaneously achieves temperature class D resistance (up to 150°C) and enhanced hydrolysis resistance, meeting the stringent LV 112 standard requirement of 3000 hours at 85°C and 85% relative humidity

Inventive Principle:
Principle #40Composite materials

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 thermoplastic polyurethane exhibits improved mechanical properties, high abrasion resistance, and increased resistance to heat and hydrolysis, meeting the stringent requirements of temperature class D and LV 112 standards, while also providing effective flame retardancy.

Implementation Method 1

reaction of a thermoplastic polyester (PE-1) with a diol (D1) to give a composition (Z1) comprising a polyester (PE-2)

Methodology Applied
Scientific EffectCondensation reaction:

Implementation Method 2

reaction of the composition (Z1) obtained in step (i) with an isocyanate composition (I1) comprising at least one polyisocyanate, and with a polyol composition (P1)

Methodology Applied
Scientific EffectPolyaddition reaction:

Data Source

PatentUS11851523B2Aging-resistant TPU
Publication Date: 2023.12.26 BASF SE

AI summary

The present invention relates to thermoplastic polyurethanes obtainable or obtained by a process comprising the reaction of a thermoplastic polyester (PE-1) with a diol (D1) to give a composition (Z1) comprising a polyester (PE-2), and the reaction of the composition (Z1) obtained in step (i) with an isocyanate composition (I1) comprising at least one polyisocyanate, and with a polyol composition (P1), where the polyol composition (P1) comprises at least one polycarbonate polyol (PC1), and also to a process for the production of the thermoplastic polyurethane. The present invention further relates to a composition comprising a thermoplastic polyurethane of the invention and at least one flame retardant. The present invention also relates to the use of this thermoplastic polyurethane for the production of cable sheathing, and also to films, moldings, rollers, fibers, automobile cladding, hoses, cable plugs, folding bellows, drag cables, cable sheathing, gaskets, belts or damping elements comprising this thermoplastic polyurethane.