Composite Fiber Core-Sheath Structure for Low Force Elongation
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Solution Overview
Problem
Existing composite fibers require a high force for elongation, leading to an uncomfortable wearing feel and potential unrecoverable elongation when used in clothing that undergoes repeated expansion and contraction.
Innovation Solution
A composite fiber with a core-sheath structure, where the core is made of a polyvinyl-based thermoplastic elastomer or a thermoplastic polyurethane elastomer with a glass transition temperature of 0° C. or lower, and the sheath is an easily soluble thermoplastic polymer, with a mass ratio of X:Y ranging from 90:10 to 50:50.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a composite fiber with a polyurethane elastomer core and easily soluble thermoplastic polymer sheath is used, then the fiber structure is improved for potential low force elongation, but high stress is still generated during elongation requiring relatively large force
Solution Approach 1:
The patent changes the material parameters by selecting specific elastomers with glass transition temperatures of 0°C or lower (such as polyvinyl-based thermoplastic elastomers or thermoplastic polyurethane elastomers with Tg ≤ 0°C). This parameter change enables the fiber to be elongated with small force while maintaining excellent elasticity and high flexibility, resolving the contradiction between strength and force required for elongation.
2Reliability
If conventional composite fibers are used to provide tightening feel, then structural support is achieved, but unrecoverable elongation occurs when subjected to repeated expansion and contraction
Solution Approach 1:
The patent uses composite materials consisting of an elastomer core (component X) and an easily soluble thermoplastic polymer sheath (component Y) in a core-sheath structure. The elastomer component provides excellent elasticity and recovery, while the specific composition (with glass transition temperature ≤ 0°C) ensures durability under repeated expansion and contraction without unrecoverable elongation, resolving the contradiction between elasticity recovery and durability.
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 fiber can be elongated with a small force, exhibits excellent elasticity and flexibility, and provides a natural wearing feel with moderate tightening, while minimizing unrecoverable elongation even under repeated expansion and contraction.
Implementation Method 1
a fiber obtained by dissolving and removing the sheath component from the composite fiber
Implementation Method 2
a thermoplastic polyurethane elastomer having a glass transition temperature of 0° C. or lower
Data Source
AI summary
The present invention relates to a composite fiber for obtaining a fiber having a strength at 100% elongation of 0.04 cN/dtex or less,wherein the composite fiber is composed of component X comprising a polyvinyl-based thermoplastic elastomer, or a thermoplastic polyurethane elastomer having a glass transition temperature of 0° C. or lower, and component Y which is an easily soluble thermoplastic polymer,wherein the composite ratio (mass ratio) X:Y of the component X and the component Y is within the range of from 90:10 to 50:50, andwherein the composite fiber has a core-sheath structure in which the component X constitutes the core component, and the component Y constitutes the sheath component, in a cross section of the fiber.