Nonwoven Nanofiber Formation via Aerodynamic Polymer Drawing
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Solution Overview
Problem
Existing non-woven fiber production methods, such as electrospinning and melt blowing, face limitations in achieving small fiber diameters, especially for high viscosity polymer melts, and are not scalable for large-scale production across different molecular weight polymers, due to inherent slowness, solvent intensity, and limited polymer availability.
Innovation Solution
A system that outputs a melted polymer into a high-speed gas stream using aerodynamic lifting and gravity forces, without pressurized flow, at a non-heated temperature below 200°C, allowing for the formation of non-woven fibers with diameters ranging from 1 nanometer to 1 micrometer, enabling higher throughput and scalability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If electrospinning is used to produce nanofibers, then fiber diameter can be reduced to nanometer scale, but production speed is inherently slow and solvent intensive
Solution Approach 1:
The patent replaces the electrostatic field-based electrospinning mechanism with a mechanical gas stream-based system. High velocity gas flow (20-100 m/s) mechanically draws and stretches polymer melts through a nozzle to form nanofibers, eliminating the need for high voltages and solvents while enabling continuous high-speed production
Solution Approach 2:
The patent changes the fundamental process parameters from electrostatic conditions (high voltage, low speed) to aerodynamic conditions (high gas velocity, atmospheric pressure). This parameter transformation enables both nanoscale fiber production and high throughput by using gas flow rates of 10-100 L/min at velocities exceeding 20 m/s
2Productivity
If melt blowing is used for fiber production, then production scalability is improved, but fiber diameters are limited to microfiber range of 2-4 μm
Solution Approach 1:
The patent introduces dynamic gas flow conditions with velocities of 20-100 m/s that actively stretch and thin the polymer melt stream as it exits the nozzle. This dynamic aerodynamic drawing process enables continuous production of nanofibers with diameters below 1 μm while maintaining high throughput scalability
Solution Approach 2:
The patent uses high velocity gas streams (pneumatic force) to replace the traditional melt blowing mechanism. The gas flow creates aerodynamic lifting and pulling forces that elongate the polymer melt into nanofibers, achieving both the scalability of melt blowing and the nanoscale dimensions previously only attainable through electrospinning
3Adaptability or versatility
If high viscosity polymer melts are used, then material selection is improved, but achieving small fiber diameters becomes difficult with conventional methods
Solution Approach 1:
The patent changes the processing conditions to high gas velocity (20-100 m/s) and atmospheric pressure, which enables the aerodynamic drawing of high viscosity polymer melts into nanofibers. The strong aerodynamic forces overcome the high viscosity resistance, allowing materials like polyethylene and polypropylene to be processed into sub-micrometer fibers without requiring molecular weight reduction
Data Source
AI summary
A system and method for forming non-woven fibers includes an extruder for melting a substance, a nozzle on an end of the extruder for outputting the melted substance, and a gas source in fluid communication with the nozzle. The nozzle may be configured to output the substance in a melted form at atmospheric pressure proximate an output of the gas source. The system may be configured to output a gas stream at lower temperature.