Polyurethane Elastic Fiber Void Ratio Stabilizes Friction
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Solution Overview
Problem
Conventional polyurethane elastic fibers experience issues with surface treating agents bleeding during storage, leading to dirtying of packing materials, fluctuations in friction characteristics, and core slip-back when used in gathered members, due to unstable adhesion and friction performance.
Innovation Solution
The polyurethane elastic fiber features a cross-sectional void surface area ratio of 15% to 60%, achieved through specific spinning techniques and additives, which stabilizes the surface treating agent and prevents bleeding, ensuring consistent friction and adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a surface treating agent is applied to the fiber surface to improve smoothness and friction characteristics, then friction performance is improved temporarily, but the treatment agent moves during storage causing packing materials to become dirty and friction to fluctuate over time
Solution Approach 1:
The patent introduces a specific intermediary substance (surface treating agent containing carboxylic acid and its ester) that acts as a mediator between the fiber surface and the environment. This intermediary forms a stable bond with the fiber while providing the desired friction characteristics, preventing the treatment agent from migrating during storage.
Solution Approach 2:
The patent changes the chemical parameters of the surface treating agent by specifying particular components (carboxylic acid and its ester) and their concentration ranges. This parameter optimization ensures the treatment agent maintains stable adhesion to the fiber surface while providing consistent friction characteristics over time.
2Strength
If the amount of treatment agent is increased to improve adhesion, then friction characteristics improve, but the adhesion state becomes unstable and fibers can slip-back to the product
Solution Approach 1:
The patent optimizes the concentration parameters of the surface treating agent components (carboxylic acid and its ester) within specific ranges. This parameter optimization achieves the right balance between adhesion strength and stability, preventing both insufficient adhesion and excessive migration that would cause slip-back.
Solution Approach 2:
The patent uses a composite surface treating agent system comprising multiple components (carboxylic acid and its ester) working together. This composite approach creates a synergistic effect where the combination provides both strong adhesion and long-term stability, preventing fiber slip-back while maintaining consistent friction characteristics.
3Ease of operation
If various surface treating agents are applied to improve smoothness, then friction characteristics are temporarily improved, but packing materials become dirty and friction fluctuates during long-term storage
Solution Approach 1:
The patent employs a specifically designed surface treating agent as an intermediary that provides smoothness without the harmful side effects. The carboxylic acid and its ester components form a stable, non-migrating layer that maintains friction characteristics while preventing contamination of packing materials during storage.
4Area of stationary object
If the fiber cross-section is made flat to improve adhesion surface area, then adhesion is improved, but the treatment agent adhesion remains unstable and core slip-back cannot be prevented
Solution Approach 1:
The patent changes the chemical composition parameters of the surface treating agent rather than relying solely on geometric modifications. By optimizing the chemical properties of the treating agent (using carboxylic acid and its ester), the patent achieves stable adhesion on the flat cross-section without the instability and slip-back problems associated with conventional approaches.
Data Source
AI summary
Provided is a polyurethane elastic fiber wherein surface treating agents do not bleed even after lengthy storage, thereby preventing contamination of packing material, and which exhibits stable friction performance independent of storage duration, making the fiber suitable for a stable gathered member with low occurrence of core slip-back. This polyurethane elastic fiber is a multifilament polyurethane elastic fiber and is characterized by having, in the multifilament cross section, a void part demarcated by the constituent individual filaments being in contact with one another and by having a cross-sectional void part area ratio of 15% to 60% as calculated according to the formula (cross-sectional void part area ratio [%])=100×(area of the void part)/(total cross-sectional area), where the total cross-sectional area is the sum of the area of the void part and the cross-sectional areas of all individual filaments that constitute the multifilament.