Recycled Polyester Filament With C-Shaped Spinneret Holes for 3D Crimp
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Solution Overview
Problem
Current recycled polyester fibers lack a three-dimensional crimp shape, limiting their application in thermal insulation and other products like filling materials and cold-proof supplies.
Innovation Solution
A method for preparing recycled polyester filament using C-shaped and circular spinneret holes with controlled distribution, followed by relaxation heat treatment, to create asymmetrical stress and thickness on the fiber cross-section, resulting in a three-dimensional crimp shape and random crimp directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If conventional spinneret holes are used for recycled polyester fiber production, then the production process is simple, but the fiber lacks three-dimensional crimp shape and thermal insulation properties
Solution Approach 1:
The patent applies asymmetry by using C-shaped spinneret holes instead of conventional circular holes. The C-shaped holes create asymmetric stress distribution during fiber formation, with one side experiencing higher stress and the other lower stress, which directly leads to the formation of three-dimensional crimp shapes in the recycled polyester fiber. This asymmetric geometry is the core mechanism for achieving the desired fiber morphology without complex additional processing steps.
Solution Approach 2:
The patent implements local quality by creating different stress conditions at different locations within the spinneret hole structure. The C-shaped hole design ensures that different regions of the fiber cross-section experience different cooling rates and stress levels, with the inner arc experiencing different conditions than the outer arc. This local variation in quality parameters (stress, cooling rate) throughout the fiber structure enables the formation of three-dimensional crimp while maintaining overall fiber integrity.
2Temperature
If C-shaped spinneret holes are used to create three-dimensional crimp, then thermal insulation properties improve, but the monofilament crimping directions become uniform causing strip unevenness
Solution Approach 1:
The patent applies dimensionality change by introducing angular orientation as an additional variable. Instead of only varying the C-shaped hole geometry, the patent distributes the holes at different angles (0°-360°) around the spinneret circumference. This adds an angular dimension to the hole distribution, causing monofilaments to crimp in different directions and preventing the uniform crimping pattern that causes strip unevenness, while still maintaining the thermal insulation benefits of three-dimensional crimp.
Solution Approach 2:
The patent implements parameter changes by systematically varying the angular position parameter of C-shaped spinneret holes. The holes are distributed at different angles (randomly or uniformly distributed in 0°-360° range), which changes the orientation parameter of the resulting fiber crimps. This parameter variation ensures that not all monofilaments crimp in the same direction, eliminating the strip unevenness problem while preserving the thermal insulation properties provided by the three-dimensional crimp structure.
3Manufacturing precision
If ring-blowing cooling is applied during FDY process, then fiber formation is controlled, but without specific temperature and wind speed control the crimp quality is insufficient
Solution Approach 1:
The patent applies parameter changes by optimizing the ring-blowing cooling parameters to specific ranges: temperature 20°C-25°C and wind speed 1.80-2.30 m/s. These precise parameter settings control the cooling rate and stress distribution during fiber formation, ensuring optimal three-dimensional crimp development. By defining specific parameter ranges rather than using arbitrary values, the patent achieves consistent high-quality crimp formation while avoiding excessive energy consumption that would result from higher wind speeds or lower temperatures.
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 method produces recycled polyester filaments with excellent mechanical properties, including three-dimensional crimp shape, improved thermal insulation, and reduced strip unevenness in knitted fabrics.
Implementation Method 1
After the melt is extruded from the C-shaped spinneret hole, the cooling rate of different positions is inconsistent
Implementation Method 2
a relaxation heat treatment is performed
Data Source
AI summary
A type of recycled polyester filament and preparation method therefor is disclosed, in the process of preparing a fiber from a recycled polyester according to the FDY process, the ring-blowing is used for cooling, and the distribution of spinneret holes on the spinneret is controlled to meet certain conditions, then a recycled polyester filament is obtained by relaxation heat treatment after a fully drawn yarn is produced; wherein the spinneret holes are C-shaped spinneret holes and circular spinneret holes, the cross-section of the C-shaped spinneret hole is composed of an outer arc M, an inner arc N and two line segments, and two endpoints of the outer arc M are A and B respectively; wherein the certain conditions comprise: all the spinneret holes are distributed in concentric circles, and the C-shaped spinneret holes are located on the outermost circle, rotating at different angles and randomly distributed; wherein the prepared recycled polyester filament has a three-dimensional crimp shape, and the monofilament crimping directions are randomly distributed. The present invention uses a simple method to produce recycled polyester filaments with three-dimensional crimp shapes, and solves the problem of "strip unevenness" in knitted fabrics made from three-dimensional crimp fibers.