Multi-zone Spinneret Capillary Design for Filament Uniformity
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Solution Overview
Problem
Current spinnerets for melt-spinning polymeric filaments often result in non-uniform filament and fabric formation due to filament breaks and hard spot defects, particularly at higher polymer throughputs, due to variations in cooling efficiency across the spinneret face.
Innovation Solution
A spinneret design with multiple zones having varying capillary dimensions, including hydraulic diameter, length, and length-to-hydraulic diameter ratios, arranged to minimize frost line variation and optimize polymer throughput, ensuring uniform quenching and reduced defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If uniform capillary dimensions are used throughout the spinneret, then manufacturing is simple, but filament uniformity deteriorates at higher polymer throughputs due to frost line variation
Solution Approach 1:
The spinneret employs different capillary dimensions in different zones (first, second, and third zones with varying hydraulic diameters and lengths) to locally optimize cooling efficiency and frost line position, thereby improving filament uniformity while maintaining overall manufacturing feasibility through modular zone design
2Productivity
If higher polymer throughput is used, then productivity increases, but filament breaks and hard spot defects increase due to cooling inefficiency
Solution Approach 1:
The invention changes capillary geometric parameters (hydraulic diameter and length) across different zones to optimize the length-to-hydraulic-diameter ratio, which controls cooling efficiency and frost line position, enabling higher polymer throughput without increasing filament breaks and hard spot defects
3Manufacturing precision
If capillary length to hydraulic diameter ratio is varied across zones, then frost line variation is reduced, but device complexity increases
Solution Approach 1:
The spinneret face is segmented into multiple zones (first, second, and third zones) with progressively varying capillary dimensions, which systematically reduces frost line variation while keeping the complexity manageable through a structured progressive design rather than complete customization
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 multi-zone spinneret design enhances filament and fabric uniformity, allows higher production throughputs, and minimizes filament breaks and hard spot defects by optimizing capillary dimensions and density across the spinneret face.
Implementation Method 1
The extruded molten filaments are attenuated while passing through a quench zone where a stream of fluid, such as air, is passed across the path of the filaments to cool or solidify them
Data Source
AI summary
A spinneret, apparatus, and method are provided for making filaments for fibrous nonwoven fabrics with more uniform filament and fabric formation while minimizing filament breaks and hard spot defects in webs and fabrics made therefrom. The spinneret has a spinneret body that has an overall length to hydraulic diameter ratio and defines orifices that extend through the spinneret body, wherein the orifices comprise capillaries that open at a face of the spinneret body for polymer filament extrusion therefrom, wherein the capillaries are arranged in a plurality of different rows at the face of the spinneret body, and wherein the plurality of different rows are arranged into a plurality of different zones at the face of the spinneret body. A spinneret body of the spinneret can have an overall length to hydraulic ratio of at least 3 percent and/or a zone-to-zone length to hydraulic ratio of at least 2% and/or the hydraulic diameters, lengths, and length to hydraulic diameter ratios can progressively increase or decrease zone-to-zone for at least three different zones of capillaries, which can be applied to cross-flow quench or quench from a single-side. The spinneret body is designed to better accommodate differing operational proximity of the various different zones to quench air sources or source at commercially useful throughputs and fiber uniformity.