Crimped Polyamide Conjugate Yarn for Uniform Wet-Heat Shrinkage
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Solution Overview
Problem
Conjugate polyamide fibers exhibit variations in shrinkage rate, orientation, and crystallinity due to slight differences in polymer viscosity, leading to issues like dyeing specks, crimped spots, and wrinkles during wet-heat processes, which affect the stretchability of woven or knitted fabrics.
Innovation Solution
A crimped polyamide yarn with a side-by-side or eccentric sheath-core structure, composed of two polyamides with different shrinkage characteristics, having a wet-heat-shrinkage stress variation rate of 150% or less, and a stretch elongation rate of 15% to 100%, to minimize shrinkage variations and improve fabric quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If two kinds of polyamides having different viscosity are combined to form conjugate fiber, then crimping property is improved, but variation in shrinkage rate increases
Solution Approach 1:
The patent applies parameter changes by carefully controlling the viscosity difference between the two polyamides to be within a specific range (0.05-0.50), and by controlling the orientation difference to be within 5 degrees. These parameter constraints resolve the contradiction by finding the optimal balance between achieving sufficient crimping property through viscosity difference while preventing excessive variation in shrinkage rate.
2Object-generated harmful factors
If tension is applied to woven or knitted fabric during wet-heat process, then wrinkles are removed, but crimps cannot be sufficiently exhibited
Solution Approach 1:
The patent changes the parameter of shrinkage rate uniformity by controlling the orientation difference between polyamides to within 5 degrees and viscosity difference within a specific range. This creates a conjugate fiber where both components shrink at similar rates during wet-heat processing, allowing crimps to be exhibited without generating wrinkles that would require tension to remove.
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 solution reduces dyeing specks and wrinkles, ensuring a fabric with consistent shrinkage and enhanced stretchability, resulting in high-quality, stretchable woven or knitted fabrics.
Implementation Method 1
two kinds of polyamides having different shrinkage characteristics are laminated in a side-by-side or an eccentric sheath-core
Data Source
Figure 1(a)~1(b)
Figure 2
AI summary
The present invention provides a latently crimped polyamide conjugate fiber which is suppressed in shrinkage rate variation and has few crepes or wrinkles due to dyeing speck or crimp unevenness, thereby having good quality. A crimped polyamide yarn according to the present invention is formed of a side-by-side type or eccentric core-sheath type polyamide conjugate fiber, and has a wet heat shrinkage stress variation rate of 150% or less.