Thermoplastic Polyurethane Multifilaments Melt Spinning
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Solution Overview
Problem
Existing melt spinning processes for thermoplastic polyurethane multifilaments often result in filament rupture during preparation, lacking in tensile strength and elongation properties, and require inefficient production methods.
Innovation Solution
The development of melt spun multifilaments based on thermoplastic polyurethane, produced through a specific reaction of organic diisocyanates, polyether carbonate polyols, chain extenders, and optional additives, with a controlled molar ratio and drying process to achieve high tensile strength and elongation properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional melt spinning processes are used for thermoplastic polyurethane multifilaments, then production can proceed with standard methods, but filament rupture occurs during preparation and mechanical properties are insufficient
Solution Approach 1:
The patent applies parameter changes by optimizing the polyol composition (using polyether polyol with specific molecular weight range of 500-2500 and polyester polyol with molecular weight of 1000-5000) and controlling the molar ratio of isocyanate groups to hydroxyl groups (1.0-1.01). These parameter adjustments result in multifilaments with tensile strength of 3.0-6.0 cN/dtex and elongation at break of 200-400%, while preventing filament rupture during preparation.
2Ease of manufacture
If conventional thermoplastic polyurethane compositions are used, then production simplicity is maintained, but the multifilaments lack sufficient elongation and elastic properties
Solution Approach 1:
The patent employs composite materials by combining polyether polyol and polyester polyol in a specific formulation. The polyether polyol (500-2500 molecular weight) provides elastic properties and low-temperature flexibility, while the polyester polyol (1000-5000 molecular weight) contributes to mechanical strength. This composite approach achieves elongation at break of 200-400% and maintains good elastic recovery, all through a conventional melt spinning process.
3Adaptability or versatility
If standard polyol molecular weights are used, then material availability is high, but the resulting multifilaments show poor low-temperature elastic properties
Solution Approach 1:
The patent applies parameter changes by specifying precise molecular weight ranges for the polyols: polyether polyol with number average molecular weight of 500-2500 and polyester polyol with number average molecular weight of 1000-5000. This control enables the multifilaments to maintain excellent elastic properties at low temperatures (down to -40°C) while remaining producible through standard melt spinning processes.
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 multifilaments exhibit improved mechanical properties, including higher tensile strength and better elongation at break, while maintaining excellent elastic properties at low temperatures, and are produced through a simplified and efficient process.
Implementation Method 1
reacting a polyol composition (A) which consists essentially of a polyester polyol (A-1) having a crystallization enthalpy of at most 70 J/g and a number average molecular weight of from 1000 to 5000, and a polyether polyol (A-2) having a number average molecular weight of from 500 to 2500, and in which the average functionality (f) of the composition (A) is between 2.006 and 2.100, and a chain extender (C), with an organic diisocyanate (B)
Implementation Method 2
a method for producing polyurethane elastic monofilaments by melt-spinning the thermoplastic polyurethane. The filaments are melt-spun and air-quenched in conventional manner
Implementation Method 3
The filaments are melt-spun and air-quenched in conventional manner
Implementation Method 4
a polyester polyol (A-1) having a crystallization enthalpy of at most 70 J/g and a number average molecular weight of from 1000 to 5000
Data Source
AI summary
The invention relates to melt spun multifilaments based on thermoplastic polyurethane, their production and the use of said melt spun multifilaments to produce technical textiles and clothing such as socks, stockings, compression textiles like medical bandage, surgical hose, orthopedic elastic bandage, sport textiles, underwear etc.