Spandex Unwinding Tension Control via Polystyrene Polymer Addition
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Solution Overview
Problem
Conventional spandex fibers exhibit irregular ballooning and tension spikes during unwinding, and their adhesive properties with hot melt adhesives are inadequate, leading to poor unwinding properties and compatibility issues in medical applications.
Innovation Solution
A polystyrene-based polymer with a number average molecular weight of 50,000 to 150,000 is added to the polyurethane-urea spinning stock solution in a slurry state, improving unwinding properties and enhancing adhesive properties with hot melt adhesives by 10% or more.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If inorganic-based anti-adhesives (Mg-st, Ca-st, Zn-st) are added to the polymer solution, then adhesion between fiber yarns is reduced, but the substance is not evenly distributed on the yarn surface causing poor unwinding properties
Solution Approach 1:
The patent changes the chemical composition parameters by replacing inorganic anti-adhesive substances with organic compounds (ethylene bis-oleylamide/stearamide, zirconium phosphate, glass, zeolite) that have better solubility and distribution characteristics in the polymer solution, thereby achieving both reduced yarn adhesion and improved unwinding properties
Solution Approach 2:
The patent uses composite anti-adhesive compositions combining multiple organic-based substances including amides, antimicrobial substances, and inorganic compounds with improved dispersion characteristics, creating a composite material system that simultaneously addresses yarn adhesion and unwinding property requirements
2Object-generated harmful factors
If conventional anti-adhesives are used to prevent yarn adhesion, then fiber yarn adhesion is reduced to some extent, but irregular ballooning and tension spikes occur during unwinding
Solution Approach 1:
The patent modifies the chemical parameters of anti-adhesive substances by using organic-based compounds with specific molecular structures (amides, antimicrobial substances) that provide controlled adhesion reduction without causing irregular ballooning or tension spikes during unwinding
Solution Approach 2:
The patent applies anti-adhesive substances with specific local properties - using compounds that selectively reduce adhesion in critical areas while maintaining uniform tension distribution during unwinding, thereby preventing both yarn adhesion and unwinding instability
3Object-generated harmful factors
If organic-based adhesive agents are applied to the polymer, then yarn adhesion is reduced, but adhesive properties with hot melt deteriorate and compatibility problems occur
Solution Approach 1:
The patent carefully controls the concentration parameters of organic anti-adhesive additives, using them at optimized levels (0.5-25 wt.%) to reduce yarn adhesion while maintaining sufficient adhesive properties for hot melt application and ensuring compatibility with spandex polymer
Solution Approach 2:
The patent employs composite formulations combining spandex polymer with controlled amounts of organic anti-adhesive substances, creating a composite material system that maintains both reduced yarn adhesion and preserved hot melt adhesive properties through synergistic material composition
Data Source
AI summary
The present invention relates to a method for preparing spandex having improved unwinding properties and enhanced adhesive properties with a hot melt adhesive and, more specifically, to a method for preparing spandex by means of adding a polystyrene polymer to a polyurethane-urea solution which is a spinning solution. Therefore, when spandex is unwound, irregular ballooning, tension spikes and the like can be effectively improved and other physical properties are unaffected. And the adhesive properties with a hot melt adhesive are enhanced.