Multi-Row Coaxial Spinneret With Angled Conduits for Isotropic Fabrics
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Solution Overview
Problem
Current multi-row coaxial spunbond and/or melt-blown type plants produce non-woven fabrics that are robust along the main development direction but weak perpendicular to it, leading to issues such as tearing and compromised liquid tightness in applications like diapers.
Innovation Solution
A spinneret design with acceleration conduits arranged in rows at different inclinations, including some at 90°, to extrude polymer filaments in multiple directions, enhancing fabric robustness and layer coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If acceleration conduits are arranged in a single direction (main development direction), then productivity is improved through efficient polymer flow, but the non-woven fabric becomes weak perpendicular to the main direction, leading to tearing and compromised liquid tightness
Solution Approach 1:
The spinneret is divided into multiple groups of acceleration conduits, with each group having a different inclination angle relative to the main development direction. This segmentation allows the polymer filaments to be deposited in multiple directions, creating a more isotropic fabric structure that resists tearing in all directions while maintaining manufacturing efficiency.
Solution Approach 2:
The acceleration conduits are deliberately arranged with asymmetric inclination angles (e.g., 0°, 45°, 90°) rather than uniform alignment. This asymmetric arrangement ensures that filaments are deposited at various orientations, enhancing the fabric's strength perpendicular to the main direction without requiring complete symmetry in all conduit configurations.
2Reliability
If acceleration conduits are arranged at multiple inclinations to improve fabric robustness in all directions, then fabric strength and durability are enhanced, but the spinneret structure becomes more complex
Solution Approach 1:
Different groups of acceleration conduits are assigned different inclination angles based on their specific position and function within the spinneret. For example, some conduits are oriented at 0° for primary deposition efficiency, while others are oriented at 45° or 90° to provide cross-directional reinforcement. This local differentiation of conduit qualities achieves enhanced reliability without requiring all conduits to be equally complex.
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 spinneret enables the production of robust non-woven fabrics and diapers with improved resistance and durability by ensuring equal strength in all directions, reducing breakage and enhancing functionality.
Implementation Method 1
The polymer inside the dispensing conduit is pushed under pressure and at high temperatures, usually above 200°C, towards the extrusion head
Implementation Method 2
the molten polymer reaches the distributor... the polymer is extruded into filaments constituting the NWF spundbond
Data Source
Figure 1~2
Figure 3~4
Figure 5~6b
AI summary
There is provided a spinneret (1) for a multi-row coaxial spunbond and/or melt-blown type plant developing along a main axis (1a) and a main plane (1b), defining a vertical axis (1c) perpendicular to the main axis and plane (1a, 1b) and comprising a first end (10) adapted to interface with a polymeric fluid distributor of a multi-row coaxial spunbond and/or melt-blown type plant; a second end (11) arranged at a side of the spinneret (1) opposite the first end (10) with respect to the main plane (1a) at which the polymer fluid exits from the spinneret (1) in the form of polymer filaments; and a plurality of acceleration conduits (2) extending at least from the first end (10) to the second end (11) each along its own dispensing axis (2a), each adapted to dispense a respective polymer filament along the dispensing axis (2a) and distributed both along a distribution axis (2b) transverse to the main axis (1a) and the vertical axis (1c) so as to create a first row (2'), and parallel to the main axis (1a) so as to make at least a second row (2") offset with respect to the first row (2') along the main axis (1a); and wherein at least one of the dispensing axes (2a) of the acceleration conduits (2) of the first row (2') defines a first angle of inclination (α') with respect to the main plane (1b) other than 90° and at least one of the dispensing axes (2a) of the acceleration conduits (2) of the second row (2') defines a second angle of inclination (α') with respect to the main plane (1b) different from the first angle of inclination (α').