Polyurethane Resin Hard Segment Domain Size
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Solution Overview
Problem
Existing polyurethane resins face a trade-off between heat resistance and stretching properties, with increasing urethane or urea group concentrations improving heat resistance but decreasing residual strain and elongation.
Innovation Solution
A polyurethane resin composition with specific molecular weight ranges for diol and organic diisocyanate components, along with a chain extender, achieving a balanced concentration of urethane and urea groups and hard segment domains for enhanced heat resistance and stretching properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the urethane group concentration and/or the urea group concentration of a polyurethane resin is increased to improve heat resistance, then the heat resistance is improved, but the residual strain or the elongation of the resin decreases
Solution Approach 1:
The invention changes the physical parameters of the hard segment domains (specifically the domain size to 20-30 nm and the concentration of urethane and urea groups to 1.25-2.50 mmol/g) to achieve a balance between heat resistance and stretching properties. This specific parameter optimization allows the resin to maintain both improved thermal stability and elastic performance.
Solution Approach 2:
The invention creates a composite microstructure within the polyurethane resin by forming discrete hard segment domains (20-30 nm) dispersed in a soft segment matrix. This composite structure at the nanoscale allows the material to simultaneously exhibit the thermal resistance of concentrated urethane/urea groups and the elasticity of the softer matrix regions.
2Temperature
If the urethane group concentration and/or the urea group concentration of a polyurethane resin is increased to improve heat resistance, then the heat resistance is improved, but the stretching properties are insufficient
Solution Approach 1:
The invention optimizes the concentration parameters of urethane and urea groups (1.25-2.50 mmol/g) and the domain size (20-30 nm) to achieve a balance between heat resistance and stretching properties. This specific parameter optimization allows the resin to maintain both improved thermal stability and elastic performance.
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 polyurethane resin exhibits high heat resistance and excellent stretching properties, including improved tensile strength, elongation, and residual strain, making it suitable for various applications.
Implementation Method 1
reacting a diol (a1) having a number average molecular weight of 500 to 10,000 and an organic diisocyanate (b1)
Implementation Method 2
The present invention relates to a polyurethane resin including, as constituent units, a diol (a1) having a number average molecular weight of 500 to 10,000, an organic diisocyanate (b), and a chain extender (a2)
Implementation Method 3
The total concentration of urethane groups and urea groups in the polyurethane resin being 1.25 to 2.50 mmol/g
Data Source
AI summary
The present invention relates to a polyurethane resin including, as constituent units, a diol (a1) having a number average molecular weight of 500 to 10,000, an organic diisocyanate (b), and a chain extender (a2). The total concentration of urethane groups and urea groups in the polyurethane resin is 1.25 to 2.50 mmol/g based on the weight of the polyurethane resin. Hard segment domains of the polyurethane resin have an average domain size of 20 to 30 nm as measured with an atomic force microscope.