Polyurethane Urea Fiber Hard Segment Optimization
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Solution Overview
Problem
Existing polyurethane urea fibers exhibit insufficient breaking extension, high tension at moderate stretching, poor recovery, and high modulus, leading to discomfort and aesthetics issues in textiles, particularly in sportswear and medical applications.
Innovation Solution
A polyurethane urea fiber or film with a hard segment content of 8.0-13.0% by weight, prepared using a copolymer glycol with specific molecular weights and aromatic carboxylic acid components, is produced through a process involving diisocyanate reaction, chain extension, and optional chain termination, resulting in high elongation, low modulus, and excellent elastic recovery with low hysteresis loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional polyurethane urea fibers are used to achieve elasticity and extensibility, then good elastic recovery is obtained, but breaking extension is insufficient and tension is high at moderate stretching
Solution Approach 1:
The patent changes the chemical composition parameters of the polyol component, specifically using copolymer polyols with aromatic carboxylic acid groups (6-20 wt%) to modify the polymer structure. This compositional parameter change enables simultaneous improvement of breaking extension (>500%) and maintenance of elastic recovery, resolving the contradiction between these two properties.
Solution Approach 2:
The invention uses composite polyol systems combining polytetrahydrofuran glycol with aromatic carboxylic acid copolymer glycols. This composite approach creates a synergistic effect where the aromatic carboxylic acid groups form specific interactions that enhance both elongation and recovery properties, overcoming the limitations of conventional single-component polyols.
2Strength
If polyurethane urea fibers with high breaking elongation are used to achieve soft stretching, then low stretch stress is obtained, but elastic recovery is poor causing bulging or lagging
Solution Approach 1:
The patent optimizes the hard segment content to 8-13 wt% and controls the molecular weight of the copolymer polyol (500-5000 g/mol) to achieve the right balance. These parameter changes ensure that the fiber can stretch beyond 500% elongation while maintaining excellent elastic recovery above 90%, preventing bulging and lagging.
Solution Approach 2:
The aromatic carboxylic acid groups are distributed within the polyol chains at specific concentrations (6-20 wt%), creating localized interaction zones that enhance both extensibility and recovery. This local quality modification allows the material to exhibit superior performance in both breaking elongation and elastic recovery simultaneously.
3Strength
If polyurethane urea fibers with high modulus are used to achieve structural stability, then strength is improved, but comfortability and aesthetics are deteriorated
Solution Approach 1:
The patent reduces the modulus to 13 MPa or lower by optimizing the soft segment to hard segment ratio and controlling the aromatic carboxylic acid content. This parameter optimization maintains sufficient structural stability while dramatically improving comfortability and aesthetics for soft-fit apparels, eliminating the harsh feel associated with high modulus fibers.
4Ease of manufacture
If conventional polyurethane urea solutions are prepared to achieve fiber production, then processing is simplified, but viscosity stability is poor and gelation occurs
Solution Approach 1:
The aromatic carboxylic acid groups in the copolymer polyol act as internal stabilizing agents that prevent gelation during processing. These functional groups create controlled interactions that stabilize viscosity without requiring complex external additives or strict processing conditions, maintaining solution stability throughout the spinning process.
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 achieves a breaking elongation greater than 500%, a modulus of 13 MPa or lower, and a hysteresis loss of 20% or less, enhancing the comfort and aesthetic properties of textile articles by providing balanced performance.
Implementation Method 1
reacting copolymer glycol with at least one diisocyanate to obtain urethane prepolymer
Implementation Method 2
excellent elastic recovery as well as low hysteresis loss
Data Source
AI summary
A polyurethane urea fiber or film is made having high elongation, low modulus, low hysteresis loss, and excellent clastic recovery. The clastic polyurethane clastic fiber or film is formed from a copolymer glycol, a diisocyanate, a chain extender and optionally a chain terminator. The hard segment content of the polyurethane fibers is in the range of 8.0-13.0% by weight.