Feather-like Polyester Fiber with Four-fold Flat Cross-section
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Solution Overview
Problem
Conventional polyester fibers, such as PET, face challenges with poor dyeability, high dyeing equipment requirements, high energy consumption, and slow degradation due to their hydrophobic nature and tight molecular structure, leading to environmental concerns with waste disposal.
Innovation Solution
The development of feather-like polyester fibers with a four-fold flat cross-section, produced using a modified polyester made from terephthalic acid, ethylene glycol, main-chain silicated diol, and fluorinated dicarboxylic acid, which enhances dye uptake, reduces dyeing temperature and time, and accelerates natural degradation through increased free volume and reduced steric hindrance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional PET fiber is used, then high strength and good elasticity are achieved, but poor dyeability and high energy consumption occur
Solution Approach 1:
The patent introduces main-chain silicated diol and fluorinated dicarboxylic acid as modifiers to change the molecular structure parameters of PET fiber. The silicated diol creates Si-O-Si bonds with longer bond length and lower internal rotation activation energy, increasing free volume. The fluorinated dicarboxylic acid reduces steric hindrance and accelerates degradation. These parameter changes enable easier dyeing at lower temperatures while maintaining fiber strength.
2Strength
If conventional PET fiber is used, then high strength is achieved, but tight molecular structure causes slow degradation
Solution Approach 1:
The patent modifies the molecular structure by incorporating main-chain silicated diol and fluorinated dicarboxylic acid. The silicated diol increases free volume through Si-O-Si bonds, while the fluorinated dicarboxylic acid specifically accelerates degradation by reducing steric hindrance around ester bonds. This allows the fiber to maintain strength during use but degrade faster when discarded, resolving the contradiction between durability and environmental friendliness.
3Shape
If flat-shaped cross-section fiber is used, then improved luster and moisture absorption are achieved, but easy to break occurs
Solution Approach 1:
The patent creates a composite molecular structure within the fiber by combining modified polyester (with silicated diol and fluorinated dicarboxylic acid) in the flat cross-section fiber. This composite approach allows the fiber to exhibit both the aesthetic benefits of flat cross-section (luster, moisture absorption) and the mechanical strength provided by the modified molecular structure, resolving the contradiction between shape benefits and strength.
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 improved dyeability, reduced energy consumption, and accelerated degradation, while maintaining mechanical properties, thus addressing the limitations of conventional fibers and promoting environmental sustainability.
Implementation Method 1
The bond length between silicon atom and oxygen atom is relatively long and the internal rotation activation energy is rather low, which is favorable to the free rotation of atoms. Meanwhile, the silicon atoms in the main chain are bonded with —CH3 which is perpendicular to the plane where —Si—O—Si— lies in, and the steric repulsion between those methyl groups will further enlarge the length of Si—O bond, in addition, the macromolecular chains themselves are also spaced by those inert methyl groups. Therefore, such silicated diol contained polyester has a fairly flexible molecular chain structure and an obviously enlarged free volume compared with unmodified one.
Implementation Method 2
During the hydrolysis process of polyester, the electron cloud density in the C—O bond is reduced by the electron-withdrawing effect of fluorine atom hence the stability of the tetrahedral anion intermediate formed by ester carbonyl together with nucleophilic attacker will also decrease, which is conducive to the nucleophilic addition reaction.
Implementation Method 3
Moreover, the steric hindrance of fluorinated dicarboxylic acid is less than that of terephthalic acid, which will promote the nucleophilic addition reaction further and significantly increase the degradation rate.
Data Source
AI summary
A type of feather-like polyester fiber and a preparing method thereof are disclosed. The preparing method is to manufacture filament from a modified polyester through a POY process with a four-fold flat spinneret and a successive DTY processes, wherein said modified polyester is the product of the esterification and the successive polycondensation reactions of evenly mixed terephthalic acid, ethylene glycol, main-chain silicated diol and fluorinated dicarboxylic acid, and the spinneret is the one set with four-fold flat shaped orifices. The obtained fiber has a dye uptake of 89.6-93.7% when dyed at 130° C., and has an intrinsic viscosity drop of 13-20% when stored at 25° C. and R.H. 65% for 60 months. This invention is simple to apply and features a product with good dyeing and degradation performance.