Non-Round Solution-Spun Spandex Filaments for Efficient Drying

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Solution Overview

Problem

Existing spandex fiber production methods primarily focus on round filaments, limiting the surface area and film thickness, which can affect drying efficiency and performance.

Innovation Solution

The production of non-round or shaped spandex filaments, such as dogbone or peanut-shaped filaments, using a spinneret with closely spaced holes or capillaries, allowing for increased surface area and thinner films, achieved through solution dry spinning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of moving object

If round spinneret holes are used for spandex fiber production, then the manufacturing process is simple, but the surface area is limited and film thickness is greater

Engineering Contradiction:
Improvesurface areaVSAvoidspinneret hole configuration
Core Design Contradiction:
Area of moving objectVSDevice complexity

Solution Approach 1:

The spinneret hole is divided into multiple segments or lobes (bilobal, trilobal, quadrilobal configurations) instead of a single round opening. This segmentation increases the surface area of the extruded filament while maintaining a manageable hole configuration in the spinneret plate.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The spinneret holes are designed with asymmetric or non-circular geometries (such as kidney-shaped, cloverleaf, or multi-lobed patterns) to create filaments with enhanced surface area and reduced film thickness. The asymmetric design allows the molten polymer to form complex cross-sections that improve drying characteristics.

Inventive Principle:
Principle #4Asymmetry

2Productivity

If round spinneret holes are used, then the device structure is simple, but drying efficiency is reduced due to limited surface area and thicker films

Engineering Contradiction:
Improvedrying efficiencyVSAvoidspinneret hole configuration
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The spinneret hole geometry transitions from a two-dimensional round cross-section to a three-dimensional multi-lobed structure. This dimensional complexity creates filaments with increased surface area-to-volume ratio, enabling more efficient solvent evaporation and improved drying efficiency without adding external drying components.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Area of moving object

If non-round spinneret holes are used, then surface area increases and film thickness decreases, but manufacturing precision requirements increase

Engineering Contradiction:
Improvesurface areaVSAvoidhole spacing and geometry control
Core Design Contradiction:
Area of moving objectVSManufacturing precision

Solution Approach 1:

The invention specifies precise parameters for non-round hole geometries including lobe count (2-8 lobes), lobe angle ranges (30-60 degrees), and hole spacing (0.25-1.27mm). By defining these parameter ranges, the patent balances the need for increased surface area with manufacturability constraints, allowing standard fabrication tolerances to produce consistent multi-lobed spinneret holes.

Inventive Principle:
Principle #35Parameter changes

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 non-round spandex filaments promote better drying and potentially enhance performance by providing more surface area and thinner films.

Implementation Method 1

a spinneret with a plate comprising two or more holes or capillaries spaced less than 1.27 mm (0.05 inches) apart

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Data Source

PatentEP3458631B1Non-round solution spun spandex filaments and methods for the production thereof
Publication Date: 2025.10.29 THE LYCRA CO UK LTD
  • EP3458631B1 patent drawingFigure 1A~1B
  • EP3458631B1 patent drawingFigure 2A~2B
  • EP3458631B1 patent drawingFigure 3A~3B

AI summary

Non-round or shaped solution spun spandex filaments as well as methods and devices for production of these non-round or shaped solution spun spandex filaments are provided.