Method for producing spunbonded webs
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Solution Overview
Problem
Existing methods for producing spunbond nonwovens, particularly cellulose-based, struggle with adjusting spinning width and maintaining consistent basis weight distribution during operation, leading to waste and inefficiencies due to thermal degradation and clogging issues with modular designs.
Innovation Solution
The method involves variably adjusting the spinning mass flow rate through die holes along the transverse direction, using temperature and pressure control to achieve uniform basis weight distribution and minimize edge cutting waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If modular spinneret design is used to adjust spinning width, then spinning width adaptability is improved, but thermal degradation and clogging occur due to shutdown modules
Solution Approach 1:
The patent implements dynamic control of individual heater zones along the spinneret length, allowing real-time adjustment of temperature distribution. This enables selective heating of active modules while keeping shutdown modules at lower temperatures, preventing thermal degradation and clogging in inactive zones while maintaining adaptability for different spinning widths
Solution Approach 2:
The patent applies local quality by differentiating temperature control for different spatial zones of the spinneret. Each heater zone can be independently controlled to match the actual melt flow requirements in that region, ensuring optimal temperature for active modules and reduced temperature for shutdown modules to prevent clogging
2Loss of substance
If spinning width is reduced to minimize waste, then material loss is reduced, but basis weight distribution becomes difficult to maintain
Solution Approach 1:
The patent changes the temperature parameter distribution along the spinneret length to control basis weight distribution. By adjusting the temperature of individual heater zones, the melt viscosity and flow rate are controlled, enabling precise control of basis weight in different transverse regions even when spinning width is reduced
Solution Approach 2:
The patent implements feedback control by measuring the basis weight distribution of the produced nonwoven fabric and using this information to adjust the heater zone temperatures. This closed-loop control system maintains precise basis weight distribution while adapting to different spinning widths and minimizing waste
3Adaptability or versatility
If spinneret plates are changed to adjust spinning width, then spinning width adaptability is improved, but production downtime increases
Solution Approach 1:
The patent replaces static mechanical adjustment (changing plates) with dynamic thermal control. The heater zones can be activated or deactivated electronically without any physical changes to the spinneret structure, allowing instant adjustment of spinning width and eliminating plate changing downtime while maintaining full adaptability
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 enables reliable, efficient production of spunbond nonwovens with adjustable basis weight distribution, reducing waste and improving productivity by maintaining consistent basis weight and quality, even with fluctuations in spinning mass.
Implementation Method 1
a spinning mass is extruded through a plurality of nozzle holes of at least one spinneret
Implementation Method 2
the filaments are deposited on a perforated conveying device to form a spunbond nonwoven fabric and wherein the nozzle holes of the spinneret are arranged along a main axis oriented in a transverse direction to the conveying direction of the conveying device
Data Source
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AI summary
The invention relates to a method for producing spunbonded fabric (1), wherein a spinning material (2) is extruded through a plurality of nozzle holes (4) of at least one spinneret (3, 40, 50) in order to form filaments (5), and each of the filaments (5) is stretched in the extrusion direction, wherein the filaments (5) are laid on a perforated conveyor device (10) in order to form a spunbonded fabric (1), and the nozzle holes (4) of the spinneret (3, 40, 50) are arranged along a main axis (6) aligned in the transverse direction (12) relative to the conveyor direction (11) of the conveyor device (10) such that the spunbonded fabric (1) formed on the conveyor device (10) is stretched in said transverse direction (12). The aim of the invention is to allow a reliable adjustment of the spinning width and the weight distribution per surface unit of the spunbonded fabric or allow the weight distribution per surface unit to be kept constant during an ongoing operation using said method. This is achieved in that the spinning material throughput (31) of the nozzle holes (4) is variably set along the transverse direction (12).