Liquid Crystal Polyester Fiber Structure for Fatigue Resistance
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Solution Overview
Problem
Liquid crystal polyester fibers exhibit weakness in compressive strength and fatigue resistance when subjected to stresses in both tensile and compressive directions, limiting their effectiveness as reinforcing materials in applications like automotive components and electronic components.
Innovation Solution
A liquid crystal polyester fiber with specific structural units, low ketone bond content, and optimized tensile and compressive strengths, enhancing its fatigue resistance through molecular chain packing and reduced side reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If liquid crystal polyester fiber is used as reinforcing material in applications requiring durability against stretching and vibration, then tensile strength is improved, but compressive strength and fatigue resistance deteriorate
Solution Approach 1:
The patent applies parameter changes by precisely controlling the ketone bond content to 0.050 mol% or less and optimizing the tensile strength to 18 cN/dtex or more and compressive strength to 0.55 cN/dtex or more. These parameter optimizations resolve the contradiction by creating a fiber structure that simultaneously achieves high tensile strength and improved fatigue resistance against both tensile and compressive stresses
Solution Approach 2:
The patent creates a composite structure at the molecular level by controlling the arrangement of structural units and minimizing ketone bonds, which creates a more uniform and resilient fiber architecture. This composite approach allows the fiber to better distribute and resist both tensile and compressive stresses, improving overall fatigue resistance
2Object-affected harmful factors
If inorganic fine particles are attached to fiber surface to improve abrasion resistance and flexural fatigue resistance, then surface durability is improved, but fatigue resistance against both tensile and compressive stresses is not sufficiently improved
Solution Approach 1:
The patent extracts the dependency on surface-mounted inorganic particles by focusing instead on controlling the intrinsic molecular structure of the fiber itself. By taking out the ketone bonds (reducing them to 0.050 mol% or less) and optimizing the structural unit arrangement, the invention achieves fatigue resistance without relying on surface particles, thereby resolving the insufficiency of particle-based solutions
Solution Approach 2:
The patent introduces controlled structural units as intermediaries that mediate between the fiber's tensile and compressive properties. These structural units act as molecular-level intermediaries that distribute stress more evenly throughout the fiber, improving fatigue resistance against both tensile and compressive stresses simultaneously
3Ease of operation
If fiber flexibility is enhanced to improve fatigue resistance against repeated bending, then flexural fatigue resistance is improved, but fatigue resistance against both tensile and compressive stresses in composite materials is not sufficiently improved
Solution Approach 1:
The patent applies parameter changes by optimizing the balance between flexibility and strength parameters. By controlling tensile strength at 18 cN/dtex or more and compressive strength at 0.55 cN/dtex or more while maintaining appropriate flexibility, the fiber achieves comprehensive fatigue resistance in composite material applications where both tensile and compressive stresses occur
Data Source
AI summary
Provided is a liquid crystal polyester fiber having excellent fatigue resistance against tensile deformation and compressive deformation. The liquid crystal polyester fiber has a ketone bond amount of 0.050 mol% or less, a tensile strength of 18 cN/dtex or more, and a single fiber compressive strength of 0.55 cN/dtex or more. For example, the liquid crystal polyester fiber may have a total amount of carboxy end groups (total CEG amount) of more than 5.0 mEq/kg and 85.0 mEq/kg or less. Further, the liquid crystal polyester fiber may include a liquid crystal polyester having a structural unit including a 2,6-naphthylene group at a proportion of 28 mol% or more based on a total content of all structural units.