Different-shrinkage composite yarn and preparation method therefor
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Solution Overview
Problem
Polyester fibers, particularly PET fibers, face challenges in dyeing due to their high crystallinity and lack of functional groups, leading to poor dye uptake and uneven dyeing, along with high energy consumption in the dyeing process, which affects their mechanical properties and processing efficiency.
Innovation Solution
The development of a modified polyester fiber with a branched diol chain segment and an elliptical spinneret arrangement, which increases the space gap between molecular chains, allowing for better dye diffusion and uniform cooling, thereby improving dyeing performance and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high temperature and high pressure method is used for dyeing PET fibers, then dye uptake rate is improved, but energy consumption increases and mechanical properties deteriorate
Solution Approach 1:
The patent modifies the chemical structure of polyester by introducing branched chain diol segments, which changes the molecular packing and creates more free volume. This structural parameter change allows dye molecules to access the fiber interior more easily at lower temperatures, reducing the need for high energy input while maintaining or improving dye uptake rate.
Solution Approach 2:
The invention creates a composite molecular structure within the polyester by combining linear chains with branched chain diol segments. This composite structure at the molecular level provides both the mechanical strength of conventional polyester and the enhanced dyeability through the branched segments that create pathways for dye diffusion.
2Quantity of substance
If high temperature and high pressure method is used for dyeing PET fibers, then dye uptake rate is improved, but mechanical properties worsen
Solution Approach 1:
By changing the molecular architecture to include branched chain segments, the patent creates a structure with increased free volume that facilitates dye penetration without requiring the high energy input that would damage mechanical properties. The branched structure modifies the packing density and intermolecular forces, enabling better dye access while preserving fiber strength.
3Productivity
If conventional cooling and blowing method is used, then production capacity is improved, but cooling uniformity and energy efficiency worsen
Solution Approach 1:
The patent employs a circular spinneret configuration with radially arranged cooling channels, creating a symmetric geometric pattern that ensures uniform heat distribution and efficient heat transfer. This circular geometry allows cooling air to reach all fiber regions equally, improving cooling uniformity while maintaining high production capacity through optimized heat dissipation pathways.
4Productivity
If conventional cooling and blowing method is used, then production capacity is improved, but cooling uniformity worsens
Solution Approach 1:
The circular spinneret design with radial cooling channels creates geometric symmetry that ensures uniform cooling across all fiber positions. This curved, radially symmetric configuration allows cooling air to distribute evenly, achieving consistent cooling uniformity while maintaining high production throughput through efficient heat dissipation.
Solution Approach 2:
The integrated cooling system within the circular spinneret serves multiple functions simultaneously: it cools the fiber, removes moisture, and maintains structural integrity during high-speed production. This multi-functional design achieves both high production capacity and uniform cooling without requiring separate systems.
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 modified polyester fibers exhibit enhanced dyeing uniformity and mechanical properties, with improved dye uptake and reduced energy consumption, maintaining the excellent properties of polyester fibers while allowing for easier processing.
Implementation Method 1
the space gap between molecular chains of modified polyester fibers is much larger than that of ordinary polyester fibers without branched chains at the same temperature, which is beneficial to the degree of tiny particles such as dye into the interior and to the higher dyeing rate
Implementation Method 2
Cooling and blowing can accelerate the cooling rate of melt fine flow, which is helpful to increase the spinning speed, strengthen the convection of air around the yarn strip, make the inner and outer layer yarn strip cool evenly
Data Source
Figure 1
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AI summary
This invention relates to the different shrinkage composite yarn and its preparation method. The modified polyester is spun with a porous spinneret to produce a different shrinkage composite yarn, and the arrangement of the spinneret holes on the porous spinneret is arranged in an elliptical arrangement. That is, the spinning hole center of the spinneret is located on the concentric ellipse, the concentric ellipse is a series of ellipses, all the ellipses are long axis collinear, and short axis collinear. The different shrinkage composite yarn is obtained by winding modified polyester POY yarn and FDY yarn, network recombining, and coiling them. The preparation method of modified polyester is as follows: terephthalic acid reacts with ethylene glycol to produce ethylene terephthalate. The modified polyester is obtained by the reaction of terephthalic acid with branched diol. The fiber of the invention has good properties and the deviation rate of fiber density. The CV value of breaking strength is ≤ 4.0%, the CV value of elongation at break is ≤ 8.0%, the CV value of coefficient of variation of coiling shrinkage is ≤ 8.0%.