Polyurethaneurea Fiber Hard Segment Optimization
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Solution Overview
Problem
Elastic polyurethane fibers struggle to achieve a balance of high recovery stress, low hysteresis loss, and high heat resistance, which is essential for applications in sport clothing, innerwear, and industrial materials, while maintaining ease of use and processing.
Innovation Solution
A polyurethaneurea fiber is produced using a copolyalkylene ether diol, diisocyanate, and diamine, with a hard segment content within a specified range of 14.0% to 25.0%, optimizing the molecular weights of urethane and urea moieties to achieve the desired properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the polyurethane is designed to provide low stretch stress, then the hysteresis loss is reduced, but the recovery stress becomes low
Solution Approach 1:
The invention changes the chemical composition parameters of the polyurethane by incorporating specific ratios of hard segments (urea and isocyanate groups) and soft segments (polyether diol). By controlling the hard segment content at 15-30% and using diamines with 2-6 carbon atoms, the material achieves optimal balance between low hysteresis loss and high recovery stress
Solution Approach 2:
The invention creates a composite polyurethane structure combining hard segments (providing strength and recovery) and soft segments (providing elasticity and low hysteresis). The specific composition of urea moieties, isocyanate groups, and polyether diol forms a multi-phase composite material that simultaneously achieves low energy loss during deformation and high recovery force
2Force
If the stretch stress is increased to provide higher support, then the fit is improved, but the clothing becomes difficult to stretch and hard to put on
Solution Approach 1:
The invention adjusts the molecular weight and composition parameters to control the stress characteristics. By using polyether diols with specific molecular weights (1000-3000) and controlling the hard segment content, the material achieves moderate stretch stress for ease of wear while maintaining high recovery stress for support during wear
3Temperature
If the hard segment content is increased to improve heat resistance, then the processability is improved, but the stretch properties may deteriorate
Solution Approach 1:
The invention optimizes the hard segment content parameter within the specific range of 15-30%, which provides sufficient heat resistance for knitting and weaving processes while maintaining adequate stretch properties for wearable applications
Solution Approach 2:
The invention creates local hard segments dispersed within the soft matrix, providing heat resistance at the molecular level while maintaining overall material flexibility and stretch properties through the continuous soft phase
Data Source
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AI summary
Provided are novel polyurethane elastic fibers having a high recovery stress, low hysteresis loss, and high heat resistance. The polyurethane elastic fibers of the present invention are polyurethane elastic fibers formed from a polyurethaneurea obtained from a copolyalkylene ether diol produced from different C2-10 alkylene ethers; a diisocyanate; and a diamine, the polyurethane elastic fibers being characterized in that the polyurethaneurea has a hard segment percentage of 14.0% to 25.0% as defined by formula (1): hard segment percentage (%) = (urea moiety number-average molecular weight)/{(urea moiety number-average molecular weight) + (moiety segment number-average molecular weight)} x 100 (formula (1)).