Spunbond Web Filament Guide for Isotropic Orientation
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Solution Overview
Problem
Existing spunbond fabrics exhibit nonisotropic properties due to filament orientation primarily in the machine direction, leading to uneven mechanical properties such as tensile strength and tear resistance, which is undesirable for technical applications.
Innovation Solution
An apparatus with a filament guide system that introduces additional transverse orientation to the filaments before deposition, using rotating shafts and disks to deflect filaments, ensuring uniform distribution and orientation across the spunbond web, thereby achieving isotropic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If filaments are deposited using conventional apparatus without additional transverse orientation, then the deposition process is simple and cost-effective, but the filaments become oriented primarily in the machine direction resulting in nonisotropic mechanical properties
Solution Approach 1:
A filament guide is introduced as an intermediary component between the stretcher and deposition device. This guide includes a movable guide part that can be displaced transversely to the machine direction, causing the filaments to follow a curved path and acquire transverse orientation components. This simple intermediary device resolves the contradiction by adding transverse orientation capability without requiring complex multi-directional stretching mechanisms or expensive specialized equipment.
2Stability of the object's composition
If a diffuser is used for deposition, then filament distribution is improved, but the filaments still orient primarily in the machine direction resulting in nonisotropic properties
Solution Approach 1:
The guide part of the filament guide is designed to be movable, allowing dynamic adjustment of the filament path during the deposition process. By displacing the guide part transversely to the machine direction, the filaments are forced to follow a curved trajectory, which imparts transverse orientation components. This dynamic adjustment capability enables isotropic property development while maintaining manufacturing simplicity, as the same basic apparatus can be used for both isotropic and nonisotropic deposition by adjusting the guide position.
3Strength
If needle-punching measures are applied to consolidate the nonwoven web, then mechanical properties are enhanced, but the nonisotropic effects are increased and the apparatus becomes more complex
Solution Approach 1:
The filament guide performs the orientation-adjusting action before deposition, preliminarily configuring the filaments with the desired transverse orientation components. This preliminary action eliminates the need for complex post-deposition consolidation measures like hyperpunch needle-punching devices that would otherwise be required to achieve isotropic properties. The orientation is built into the deposited web structure itself, simplifying the overall apparatus while maintaining enhanced mechanical properties.
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 apparatus ensures identical strength properties in both the machine and transverse directions, enhancing dimensional stability and tear propagation resistance while maintaining a homogeneous basis weight, and is cost-effective and operationally reliable.
Implementation Method 1
a cooling chamber (2) for cooling the filaments
Implementation Method 2
aerodynamically stretched filaments
Data Source
AI summary
An apparatus for the continuous manufacture of a spunbond web from aerodynamically stretched thermoplastic filaments has at least one spinneret, a cooling chamber for cooling the filaments, a stretcher, and a deposition device for the deposition of the filaments to form the spunbond web. At least one filament guide having a plurality of filament-guide gaps opens toward the stretcher between the stretcher and the deposition device, and the filament guide or at least one guide part of the filament guide can be moved such that the filament-guide gap or the stretcher-side openings thereof are displaced transversely to the travel direction of the spunbond web. Thus the filaments or filament bundles guided along or through the filament-guide gap are given a transverse orientation to the travel direction of the spunbond web when deposited onto the deposition device.