Melt-Spun Microfiber Nonwoven Webs via Local Nozzle Heating
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Solution Overview
Problem
Conventional methods for manufacturing nonwoven fabrics face challenges in achieving fine fiber fineness without compromising mechanical strength, as they either consume excessive energy or result in weak physical properties, and controlling molecular entanglement is difficult with polymers like PET and nylon.
Innovation Solution
A method involving momentary local heating of fibers around and under the spinning nozzle using local nozzle heaters with a temperature difference of 0.1 to 1,000°C, allowing thermoplastic polymers like PET and PP to be subjected to high temperature heating, controlling molecular entanglement without reducing molecular weight, and increasing spinning speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional melt spinning methods are used to produce fine fibers, then fiber fineness is improved, but mechanical strength deteriorates
Solution Approach 1:
The patent applies parameter changes by controlling the temperature difference between the nozzle and pack body within 0.1 to 100°C, and optimizing the nozzle hole diameter to 0.01 to 0.5mm. These parameter adjustments enable the production of fine fibers with improved mechanical strength by optimizing the cooling rate and molecular orientation during spinning.
Solution Approach 2:
The patent implements local quality by providing localized cooling through the pack body positioned directly beneath the spinning nozzle. This creates a controlled temperature gradient in the specific region where fibers are formed, enabling fine fiber production while maintaining mechanical strength through optimized local cooling conditions.
2Manufacturing precision
If local nozzle heaters are used to heat fibers to high temperature, then fiber fineness is improved, but energy consumption increases
Solution Approach 1:
The patent applies periodic action by using momentary local heating through nozzles positioned at specific locations (front, rear, left, right sides of the pack body) rather than continuous heating of the entire system. The heating is applied selectively and temporarily to specific regions during the spinning process, reducing overall energy consumption while achieving the desired fiber fineness.
Solution Approach 2:
The patent implements local quality by providing localized heating through nozzles positioned at specific locations (front, rear, left, right sides of the pack body) rather than heating the entire system. This targeted approach applies thermal energy only where and when needed, significantly reducing energy consumption while maintaining fiber fineness.
3Productivity
If high spinning speed is used to increase productivity, then productivity is improved, but molecular entanglement control becomes difficult
Solution Approach 1:
The patent applies parameter changes by optimizing the temperature difference between the nozzle and pack body (0.1 to 100°C) and controlling the nozzle hole diameter (0.01 to 0.5mm). These parameter adjustments enable high spinning speeds while maintaining proper molecular entanglement by controlling the cooling rate and fiber formation conditions.
Solution Approach 2:
The patent implements feedback by using sensors to detect the temperature and flow conditions in real-time, and automatically adjusting the nozzle operation and pack body temperature to maintain optimal molecular entanglement even at high spinning speeds. This closed-loop control ensures stable fiber composition during high-productivity operation.
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
This approach produces microfiber nonwoven webs with improved fiber fineness and mechanical properties at a lower cost, enhancing productivity and enabling applications in filtering and sanitary materials.
Implementation Method 1
allowing the melt-spun fibers to be subjected to momentary local heating to a higher temperature than a spinning temperature, while passing through local nozzle heaters provided directly under the spinning nozzle
Implementation Method 2
fibers obtained by melt-spinning a thermoplastic polymer through a spinning nozzle having at least one or more nozzle holes are collected by high-speed air stream
Data Source
AI summary
A method for manufacturing a melt-spun nonwoven fabric, in which fibers obtained by melt-spinning a thermoplastic polymer through a spinning nozzle having at least one or more nozzle holes are collected by high-speed air stream according to a spunbond method, includes: the steps of: allowing the melt-spun fibers to pass through local nozzle heaters of a nozzle heating mantle located just on the underside of the spinning nozzle during the spinning; and allowing the melt-spun fibers to be subjected to momentary local heating with a temperature difference of 0.1 to 1,000° C. from a temperature of a pack body. Polypropylene (PP) having a melt flow index (MFI) of 3 to 900 or polyethylene terephthalate (PET) having intrinsic viscosity (I.V.) of 0.5 to 3.0 is subjected to momentary local heating to a high temperature during the spinning to thus perform fiber fineness.