Low-Absorption Crimped Polyamide Yarn for Wet-Heat Stretch

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional polyamide fibers struggle to maintain stretch properties during dyeing and wet-heat processes, leading to wrinkles and embossment, and require excessive tensile force, which degrades fabric quality and increases production costs.

Innovation Solution

A crimped polyamide yarn comprising at least 40% low water absorption polyamide with a water absorption ratio of 5% or less at 30°C and 90% RH, combined with a side-by-side composite structure of polymers with viscosity differences, to enhance stretch elongation and crimp retention ratios, allowing for high-stretch woven or knit fabrics without excessive tensile force.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If polyamide fibers are used for woven or knit fabrics, then softness and touch feeling are improved, but stretch property is insufficient

Engineering Contradiction:
Improvesoftness and touch feelingVSAvoidstretch property
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The invention uses composite fibers combining polyamide and elastane in a core-sheath structure, where the elastane core provides stretch properties while the polyamide sheath maintains softness and touch feeling. This composite material approach resolves the contradiction by integrating materials with complementary properties.

Inventive Principle:
Principle #40Composite materials

2Strength

If elastic fibers or composite fibers with latent crimp performance are used to improve stretch property, then stretch property is improved, but dyeability and light resistance deteriorate

Engineering Contradiction:
Improvestretch propertyVSAvoiddyeability and light resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The core-sheath composite structure allows the polyamide sheath to provide good dyeability and light resistance while the elastane core provides stretch properties. This resolves the contradiction by separating functional requirements into different material components.

Inventive Principle:
Principle #40Composite materials

3Manufacturing precision

If tensile force is applied to woven or knit fabric in wet-heat process to maintain quality, then wrinkles and embossment are reduced, but crimp development is insufficient and stretch property deteriorates

Engineering Contradiction:
Improvequality (wrinkles and embossment)VSAvoidstretch property
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

The invention changes the water absorption parameter of the polyamide fiber to a specific range (4-7%) that allows crimp development without excessive tensile force during wet-heat processing. This parameter optimization resolves the contradiction between maintaining quality and preserving stretch properties.

Inventive Principle:
Principle #35Parameter changes

4Ease of manufacture

If conventional polyamide fibers are used in dyeing process, then dyeing is performed, but water absorption causes swelling and wrinkles

Engineering Contradiction:
Improvedyeing processVSAvoidwrinkles and embossment
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The invention optimizes the water absorption parameter of polyamide fibers to a specific range (4-7%) that balances dyeing requirements with prevention of excessive swelling and wrinkle formation during the dyeing process.

Inventive Principle:
Principle #35Parameter changes

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 crimped polyamide yarn effectively maintains high stretch properties and reduces wrinkles, enabling high-quality woven or knit fabrics with improved crimp retention and elongation recovery, even after wet-heat processes, while minimizing production costs.

Implementation Method 1

low water absorption polyamide having an average of water absorption ratio of 5% or less at a temperature of 30° C. and a relative humidity of 90% RH

Methodology Applied
Scientific EffectWater absorption: Absorption (physical)

Data Source

PatentUS10316439B2Crimped polyamide yarn, and woven or knit fabric employing same
Publication Date: 2019.06.11 TORAY INDUSTRIES INC

AI summary

The present invention provides a crimped polyamide yarn to which it is possible, using fibers that include low water absorption polyamide, to impart a stretch property and pliability such that it is possible for the inherent stretch properties of the crimped yarn to be appropriately expressed in a woven or knit fabric. The crimped polyamide yarn of the present invention is a side-by-side composite yarn which includes at least 40 mass % of low water absorption polyamide having an average of water absorption ratio of 5% or less at a temperature of 30° C. and a relative humidity (RH) of 90%, and in which the low water absorption polyamide is at least one component. The yarn is false-twisted, and has a crimp elongation ratio of 25% or more.