Transparent TPU Composition for Heat-Resistant Pneumatic Hoses
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Solution Overview
Problem
Existing thermoplastic polyurethanes used for hoses suffer from reduced burst pressure at elevated temperatures and expansion under compressive stress, leading to signal transmission issues and unwanted tearing.
Innovation Solution
A thermoplastic polyurethane is produced using propane-1,3-diol as the sole chain extender, combined with specific polyisocyanate and polyol compositions, particularly methylene diphenyl diisocyanate and polytetrahydrofuran, to achieve high burst pressure and heat distortion resistance, maintaining transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional thermoplastic polyurethanes are used for hoses, then processing is simplified, but burst pressure decreases at elevated temperatures
Solution Approach 1:
The patent changes the chemical composition parameters of the polyurethane by specifying exact ratios of polyol (30-70 wt%), chain extender (10-30 wt%), and polyisocyanate (20-40 wt%), along with specific molecular weight ranges, to achieve both high burst pressure and temperature stability simultaneously
Solution Approach 2:
The invention creates a composite polyurethane system combining multiple components with specific functions: polyol provides base polymer matrix, chain extender enhances strength and burst pressure, and polyisocyanate forms crosslinked structure for temperature resistance, achieving synergistic performance
2Reliability
If conventional hose materials are used, then manufacturing is easier, but hoses expand under compressive stress causing signal transmission issues
Solution Approach 1:
The patent optimizes the molecular weight parameters of components (polyol: 500-5000 g/mol, chain extender: 60-400 g/mol) and their ratios to create a polyurethane with controlled elasticity and dimensional stability that resists expansion under compression while maintaining processability
3Strength
If ester variants with high burst pressure are used, then burst pressure requirement is met, but transparency is lost making them unsuitable for many applications
Solution Approach 1:
The patent selects specific transparent polyol components with molecular weights in the range of 500-5000 g/mol and controls their ratio (30-70 wt%) to maintain optical transparency while achieving the required burst pressure through optimized composition and crosslinking structure
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 polyurethane exhibits a burst pressure of over 20 bar at 70°C and localized bursting, with high heat distortion resistance and transparency, suitable for pneumatic hoses.
Implementation Method 1
propane-1,3-diol as chain extender
Implementation Method 2
conversion of at least a polyisocyanate composition, propane-1,3-diol as chain extender and a polyol composition
Implementation Method 3
It is also possible to influence stability via the processing, for example by heat treatment
Data Source
AI summary
The present invention relates to a thermoplastic polyurethane obtainable or obtained by the conversion of at least a polyisocyanate composition, propane-1,3-diol as chain extender and a polyol composition, wherein no further chain extender is used aside from propane-1,3-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.