Polyamide 46 Multifilament Drawing for Strength and Thermal Stability
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Solution Overview
Problem
Conventional polyamide 46 multifilament yarns lack the ability to simultaneously achieve high strength, high thermal dimensional stability, and high stretchability, making them unsuitable for applications requiring both properties.
Innovation Solution
A polyamide 46 multifilament produced through melt-spinning and multi-step drawing, with specific draw ratios and heat treatment, maintaining molecular orientation and crystallinity to achieve high strength and thermal stability while allowing for high stretchability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional stretchability development techniques are used (Taslan processing with semi-drawing polyamide multifilament as sheath yarn), then stretchability is improved, but strength is impaired
Solution Approach 1:
The patent applies parameter changes by precisely controlling the draw ratios in each drawing step (first drawing: 1.5-2.5, second drawing: 1.05-1.20, third drawing: 1.00-1.10) and setting specific spinning conditions (temperature 280-320°C, vacuum degree 10-100 Pa) to achieve the optimal balance between strength and stretchability. This resolves the contradiction by finding specific parameter values that satisfy both requirements simultaneously.
2Stability of the object's composition
If polyamide 46 is used to achieve high melting point and high strength, then thermal dimensional stability is improved, but stretchability deteriorates
Solution Approach 1:
The patent applies preliminary action by performing heat treatment at 80-120°C for 0.5-48 hours before the final drawing step. This pre-heat treatment modifies the molecular structure and crystallinity in advance, creating a more favorable state for subsequent drawing operations. As a result, the yarn achieves both high thermal dimensional stability (heat shrinkage rate 0.1-3.0%) and high stretchability (elongation rate difference <1.5%) simultaneously.
3Strength
If high strength is achieved through improved spinning and drawing conditions, then strength is improved, but stretchability remains insufficient
Solution Approach 1:
The patent applies segmentation by dividing the drawing process into three distinct steps, each with specific draw ratios and conditions. The first drawing (1.5-2.5) establishes basic orientation, the second drawing (1.05-1.20) with intermediate heat treatment refines the structure, and the third drawing (1.00-1.10) provides final optimization. This segmented approach allows progressive development of both strength and stretchability without compromising either property.
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 resulting polyamide 46 multifilament exhibits strength of 6.0 to 9.0 cN/dtex, elongation at break of 15% to 30%, and heat shrinkage rate of 0.5% to 2.0%, demonstrating high strength, thermal dimensional stability, and stretchability, suitable for industrial applications like belt cords and sewing threads.
Implementation Method 1
produced by melt-spinning polyamide 46
Implementation Method 2
melt-spinning and multi-step drawing
Implementation Method 3
heat treatment at 120° C. for 24 hours
Implementation Method 4
thermal dimensional stability
Implementation Method 5
subjecting the undrawn yarn to multi-step drawing, wherein the multi-step drawing contains at least a first step drawing and a final step drawing
Implementation Method 6
maintaining molecular orientation and crystallinity
Data Source
AI summary
A polyamide 46 multifilament has a strength of 6.0 to 9.0 cN/dtex and an elongation at break of 15% to 30%, an elongation rate (E′10) of less than 2.5% after heat treatment at 120° C. for 24 hours and subsequent stretching performed 10 times in a room temperature environment, and the difference (E′10−E′1) between the elongation rate (E′1) of the heat-treated fiber measured after stretching it once in a room temperature environment and its elongation rate (E′10) measured after stretching it ten times in a room temperature environment is less than 0.60%.