TPU Pneumatic Tube Composition for High-Temperature Burst Resistance

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Solution Overview

Problem

Existing thermoplastic polyurethanes for hose applications lack sufficient burst pressure at elevated temperatures and heat distortion resistance, making them unsuitable for many applications, especially pneumatic hoses and cable sheathing.

Innovation Solution

A thermoplastic polyurethane is produced using a polyisocyanate composition, ethane-1,2-diol as the sole chain extender, and a polyol composition that includes polytetrahydrofuran, which provides improved burst pressure and heat distortion resistance, particularly at 70°C, with a burst pressure exceeding 20 bar and enhanced creep characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional thermoplastic polyurethanes are used for hose applications, then processing is simplified, but burst pressure at elevated temperatures is insufficient

Engineering Contradiction:
Improveburst pressureVSAvoidheat resistance
Core Design Contradiction:
StrengthVSTemperature

Solution Approach 1:

The patent changes the chemical composition parameters of the polyurethane by using specific polyol mixtures (polyester polyol and polyether polyol in specific ratios) and controlled chain extension with ethane-1,2-diol, which fundamentally alters the material's thermal and mechanical properties to achieve both high burst pressure and heat resistance simultaneously

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite polyurethane system by combining polyester polyol and polyether polyol in specific proportions (where the polyether polyol content is 10-50% by weight), leveraging the complementary properties of both polyol types to achieve superior burst pressure and heat resistance compared to conventional single-polyol systems

Inventive Principle:
Principle #40Composite materials

2Strength

If multiple chain extenders are used to improve burst pressure, then mechanical properties improve, but heat distortion resistance deteriorates

Engineering Contradiction:
Improveburst pressureVSAvoidheat distortion resistance
Core Design Contradiction:
StrengthVSStability of the object's composition

Solution Approach 1:

The patent extracts and eliminates all chain extenders except ethane-1,2-diol from the formulation, demonstrating that the combination of specific polyols with this single chain extender achieves both high burst pressure and heat distortion resistance, whereas conventional formulations using multiple chain extenders fail to maintain heat resistance

Inventive Principle:
Principle #2Taking out (Extraction)

3Strength

If ester variants are used to achieve high burst pressure, then strength improves, but transparency is lost and heat distortion resistance decreases

Engineering Contradiction:
Improveburst pressureVSAvoidheat distortion resistance
Core Design Contradiction:
StrengthVSStability of the object's composition

Solution Approach 1:

The patent creates a composite polyol system where polyether polyol (providing heat resistance and transparency) is combined with polyester polyol (providing burst pressure), with the polyether content controlled at 10-50% by weight, achieving a balance of all three properties that neither pure ester nor pure ether variants can achieve alone

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes the ratio parameters of polyester to polyether polyol and controls the chain extension degree by limiting ethane-1,2-diol content, which simultaneously optimizes burst pressure, heat distortion resistance, and transparency to meet all application requirements

Inventive Principle:
Principle #35Parameter changes

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 excellent burst pressure and heat distortion resistance, making it suitable for high-temperature applications such as pneumatic hoses and cable sheathing, with improved creep characteristics and Shore hardness.

Implementation Method 1

conversion of at least a polyisocyanate composition, ethane-1,2-diol as chain extender and a polyol composition

Methodology Applied
Scientific EffectPolyaddition reaction: Chemical Bonding

Data Source

PatentUS11168175B2TPU pneumatic tubes made with mono ethyleneglycol as chain extender for high temperature use
Publication Date: 2021.11.09 BASF SE

AI summary

The present invention relates to a thermoplastic polyurethane obtainable or obtained by the conversion of at least a polyisocyanate composition, ethane-1,2-diol as chain extender and a polyol composition, wherein no further chain extender is used aside from ethane-1,2-diol, to a process for preparing such a thermoplastic polyurethane, and to the use of such a polyurethane for production of injection molded products, extrusion products, films and shaped bodies.