Modified Polyester Industrial Sewing Thread
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Solution Overview
Problem
Polyester fibers face challenges in dyeing due to their hydrophobic nature and compact molecular structure, leading to difficult dye penetration and low dye uptake, which requires high energy consumption and limited dye options.
Innovation Solution
The use of modified polyester fibers produced through a process involving tert-butyl branched dicarboxylic acid, trimethylsilyl branched diol, and doped Sb2O3 catalyst, which enhances void free volumes and catalytic activity, allowing for improved dye penetration and reduced energy consumption during the dyeing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional polyester fiber is used, then the fiber has good mechanical properties and strength, but the dyeing performance is poor due to hydrophobic nature and compact molecular structure
Solution Approach 1:
The patent introduces grafted side chains at specific locations along the polyester molecular chain to create local regions of increased free volume. These localized modifications allow dye molecules to penetrate more easily without compromising the overall mechanical strength of the fiber, as the main chain structure remains intact.
Solution Approach 2:
The patent creates a composite molecular structure by grafting side chains onto the polyester main chain. This composite structure combines the strength-providing polyester backbone with the dyeing-enhancing grafted side chains, achieving both good mechanical properties and improved dyeing performance simultaneously.
2Quantity of substance
If high temperature and high pressure are used for dyeing polyester, then dye uptake can be achieved, but energy consumption increases and dyeing process becomes complex
Solution Approach 1:
The patent changes the physical-chemical parameters of the polyester fiber by introducing grafted side chains that increase void free volume. This structural parameter change allows dye molecules to penetrate the fiber more easily at lower temperatures and pressures, significantly reducing energy consumption while maintaining high dye uptake.
3Productivity
If antimony compounds are used as catalyst in large dose, then polyester synthesis can be catalyzed effectively, but the production mode becomes non-environmentally-friendly and the polyester product turns gray and dull
Solution Approach 1:
The patent changes the catalyst system from conventional antimony compounds to a novel catalyst with different chemical properties. This parameter change in catalyst type enables effective polyester synthesis at lower dosages, reducing environmental impact and preventing the grayish discoloration caused by excessive antimony compounds.
Solution Approach 2:
The patent replaces persistent antimony compounds with a more environmentally friendly catalyst system that can be used at lower dosages. This substitution reduces the accumulation of harmful substances in the environment and improves product quality without sacrificing synthesis efficiency.
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 dye uptake and improved mechanical properties, achieving higher dyeing efficiency with lower temperatures and energy consumption, while also reducing the environmental impact by minimizing antimony usage.
Implementation Method 1
the branched groups will move prior to the main chain, and when the temperature of dyeing bath reaches 120 ̃130° C., the movements of branched groups become more intense than those of main chains, so as to form more void free volumes which are larger in size than the slit free volumes generated by the main chains
Implementation Method 2
the modified polyester is the product of esterification and the following polycondensation of evenly mixed terephthalic acid, ethylene glycol, the tert-butyl branched dicarboxylic acid, the trimethylsilyl branched diol and the doped Sb2O3 powder
Data Source
AI summary
A type of polyester yarn for an industrial sewing thread and preparing method thereof are provided. The preparing method is composed of a viscosity enhancing by a solid state polycondensation and a melt spinning for a modified polyester, and the modified polyester is a product of esterification and polycondensation of evenly mixed terephthalic acid, ethylene glycol, tert-butyl branched dicarboxylic acid, trimethylsilyl branched diol and a doped Sb2O3 powder, wherein the tert-butyl branched dicarboxylic acid is selected from the group consisting of 5-tert-butyl-1,3-benzoic acid, 2-tert-butyl-1,6-hexanedioic acid, 3-tert-butyl-1,6-hexanedioic acid and 2,5-di-tert-butyl-1,6-hexanedioic acid. Moreover, the modified polyester is dispersed with a doped ZrO2 powder. An obtained fiber has an intrinsic viscosity drop of 23-28% when stored at 25° C. and R.H. 65% for 60 months.