Polyurethane Elastic Fiber with Optimized Polyol Molecular Weight
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Solution Overview
Problem
Conventional polyurethane elastic fibers struggle to maintain high active force and recovery properties when fabric thickness is reduced, leading to uncomfortable and poorly fitting clothing.
Innovation Solution
Development of a polyurethane elastic fabric using a polyol with a minimum number average molecular weight of 450 and a maximum of 1600, combined with an organic diisocyanate compound and a diamine compound, spun from a solution-polymerized polyurethane polymer solution, with specific molecular weight ratios and terminal group concentrations to achieve enhanced strength and recoverability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the fabric is thinned and lightened to provide softer texture and comfort, then the fabric weight and thickness are reduced, but the active force and recovery properties are insufficient leading to poor fit
Solution Approach 1:
The patent changes the chemical composition parameters of the polyurethane elastic fiber by specifying a polyol with number average molecular weight of 450-1600 and using a diamine compound with specific terminal group concentration (5-50 meq/kg), thereby achieving at least 1.5 times the active force and recovery per unit fineness compared to conventional fibers
Solution Approach 2:
The patent creates a composite polyurethane urea polymer structure by reacting polyol with organic diisocyanate compound to form prepolymer, then reacting with diamine compound to achieve high-powered elastic fiber properties
2Strength
If the polyol molecular weight is increased to improve strength, then the tensile strength increases, but the active force per unit fineness at 100-200% elongation is not sufficiently enhanced
Solution Approach 1:
The patent optimizes the polyol molecular weight parameter to a specific range (450-1600) that balances tensile strength with high active force per unit fineness, and controls the terminal group concentration of the polyurethane urea polymer at 5-50 meq/kg to achieve the desired elastic properties
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 solution results in a polyurethane elastic fiber with at least 1.5 times the active force and recovery per unit fineness at 100 to 200% elongation compared to conventional fibers, enabling comfortable wear and fit in thin and light fabrics.
Implementation Method 1
a prepolymer is synthesized by reacting a molar excess of organic diisocyanate compound with a polymer diol having hydroxyl groups at both ends
Implementation Method 2
using the polyurethane urea polymer solution obtained by reacting a diamine compound with the prepolymer
Implementation Method 3
spin the polymer solution at a temperature range of between 90 and 130° C.
Data Source
AI summary
To provide elastic fabric that has comfortable wear and fit even in thin and light fabric by using a high-powered polyurethane elastic fiber that has at least 1.5 times the active force and recovery per unit fineness at the time of 100 to 200% elongation compared to conventional polyurethane elastic fiber. Resolution means an elastic fabric comprising a polyurethane elastic fiber made of a polyol, with a molecular weight between 450 and 1600 with a ratio of weight average molecular weight to number average molecular weight of at least 1.8, an organic diisocyanate compound, and a diamine compound.