Dimensionally Stable Polyester Yarn via High-Speed Spin-Draw
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Solution Overview
Problem
Polyester yarns for tire reinforcement lack sufficient energy to break and dimensional stability for high-speed and run-flat tire applications, where existing manufacturing processes face challenges in achieving the required properties, especially at high spinning speeds.
Innovation Solution
A continuous spin-draw-winding process that stabilizes polyester yarn production by setting the spinning speed at 4600 to 5500 m/min, combined with rapid gaseous cooling and high draw ratios, inducing orientation-induced crystallization and high crystallinity in the filaments, resulting in drawn polyester yarns with high energy to break and improved dimensional stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If spinning speed is increased to improve productivity, then output increases, but filament breakage occurs and manufacturing reliability deteriorates
Solution Approach 1:
The patent applies parameter changes by optimizing the spinning speed to a specific range (4600-5500 m/min) and controlling the draw ratio (1.27-1.56) to achieve stable production at high speeds without filament breakage. This resolves the contradiction by finding the optimal parameter window that simultaneously improves productivity and maintains reliability.
Solution Approach 2:
The patent employs preliminary action through orientation-induced crystallization during the spinning process, where the filaments are pre-oriented and crystallized before the drawing step. This preliminary structural preparation allows the yarn to withstand high spinning speeds without breakage, enabling both high productivity and reliability.
2Stability of the object's composition
If draw ratio is increased to improve dimensional stability, then crystallinity increases, but energy to break may decrease
Solution Approach 1:
The patent resolves this contradiction by precisely controlling the draw ratio within the range of 1.27-1.56, which is sufficient to achieve the required crystallinity (30-50%) and dimensional stability without excessive drawing that would reduce energy to break. This optimal parameter selection balances both requirements.
Solution Approach 2:
The orientation-induced crystallization during spinning performs a preliminary orientation of the polymer chains before drawing. This pre-orientation reduces the stress concentration during subsequent drawing, allowing higher draw ratios to be achieved while maintaining adequate energy to break values.
3Ease of manufacture
If continuous spin-draw-winding process is used to improve ease of manufacture, then production efficiency increases, but manufacturing precision becomes more difficult to control
Solution Approach 1:
The patent maintains manufacturing precision in the continuous process by implementing specific parameter controls: spinning speed (4600-5500 m/min), draw ratio (1.27-1.56), and crystallinity (30-50%). These controlled parameters ensure consistent yarn properties throughout continuous production, resolving the contradiction between ease of manufacture and manufacturing precision.
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 process produces polyester yarns with enhanced energy to break and dimensional stability, enabling their use in high-speed and run-flat tires by achieving stable production at previously unattainable spinning speeds and improving performance metrics such as TASE 5% s.c.d.c. and energy to break.
Implementation Method 1
solidifying the spun filaments by a gaseous cooling medium
Implementation Method 2
inducing orientation-induced crystallization and high crystallinity in the filaments
Data Source
AI summary
A continuous spin-draw-winding process to prepare a drawn polyester yarn suitable for use in high-speed tires and run-flat tires having high energy to break in combination with a good dimensional stability, comprising extruding molten polyester through spinning holes in a spinneret to form a bundle of molten spun filaments, solidifying the spun filaments by a gaseous cooling medium, fixing the spinning speed of the solidified filaments at a first godet in the range of 4050 to 5000 m/min for DMT-based polyester or 4500 to 5500 m/min for PTA-based polyester, drawing the solidified filaments at a draw ratio less than 1.75 for DMT-based polyester or less than 1.60 for PTA-based polyester, to form drawn filaments. The drawn polyester yarn has a high amorphous orientation distribution, a high crystallinity and a coarse structure. Dipped cords comprising such polyester drawn yarns exhibit excellent dimensional stability at higher temperatures.