Spinnable composition (SC), and polyester fibers (PF) made therefrom
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Solution Overview
Problem
The existing melt spinning process for producing polyester fibers has a narrow production window due to conflicting factors like melt strength and viscosity at high shear rates, limiting the temperature range and resulting in inefficient fiber production and dyeability.
Innovation Solution
A spinnable composition comprising 80-99.5% terephthalate polyester, 0.49-19.9% aliphatic-aromatic polyester, 0.01-3% oligomer, and 0-5% additive, which allows for higher temperature spinning and wider production window, improving dyeability and fiber properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the temperature of the melt is increased to improve flow rate and throughput, then the flow rate increases and production speed improves, but the polyester fibers can tear under their dead weight due to reduced melt strength
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition parameters of the polyester mixture. Specifically, it combines PBT (polybutylene terephthalate) with a small amount of oligomer (0.1-5 wt%) to change the rheological parameters of the melt. This composition modification allows the melt to maintain adequate strength at higher temperatures while achieving improved flow rate and throughput, thus resolving the contradiction between productivity and melt strength.
2Productivity
If the temperature of the melt is increased to improve flow rate, then the flow rate increases, but the viscosity at high shear rates increases leading to a narrow production window
Solution Approach 1:
The patent employs composite materials by creating a blended polyester system consisting of PBT as the base polymer with oligomer additives. This composite composition exhibits synergistic rheological properties where the oligomer modifies the melt behavior to maintain low viscosity at high shear rates while broadening the acceptable temperature range for spinning. The composite nature of the material allows simultaneous achievement of high flow rate and wide production window.
3Ease of manufacture
If conventional polyester compositions are used, then the spinning process is simple, but the dyeability of the polyester fibers is poor
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition to include specific oligomers (0.1-5 wt%) in the PBT-based polyester mixture. This compositional parameter change fundamentally improves the dyeability of the resulting fibers without complicating the spinning process. The oligomer incorporation creates functional groups or structural features that enhance dye affinity, allowing conventional spinning equipment and procedures to be used while achieving superior dyeing performance.
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 enables polyester fibers to be spun at higher temperatures with a broader production window, ensuring improved dyeability, light and wash fastness, and a broad color spectrum, suitable for blends with other fibers like wool or cotton.
Implementation Method 1
Heating gives rise to a melt which is extruded through spinnerets to obtain the polyester fibers
Implementation Method 2
the flow rate of the melt which is extruded through the spinnerets
Data Source
AI summary
The present invention relates to a process for the preparation of a spinnable composition (sC) by mixing at least one terephthalate polyester (A), at least one aliphatic-aromatic polyester (B), at least one oligomer (C) and optionally at least one additive (D). Moreover, the present invention relates to the spinnable composition (sC) obtained by this process, a process for the preparation of polyester fibers (PF) by extruding the spinnable composition (sC) through at least one spinneret, the polyester fibers (PF) obtained by this process, textile materials (T) comprising the polyester fibers (PF) a process for dying the textile materials (T), and the use of the oligomer (C) for the improvement of the rheology and/or the dyeability of a composition comprising at least one terephthalate polyester (A) and at least one aliphatic aromatic polyester (B).