Polycarbonate Diol Composition for Viscosity and Color Tone Control
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Solution Overview
Problem
The existing polycarbonate diol compositions face issues with color tone compatibility with other polyols and solvents, and there is a need for improved stability and handling in polyurethane production.
Innovation Solution
A polycarbonate diol composition with a specific structure, comprising repeating structural units represented by general formulas (I), (II), (III), and (IV), and satisfying certain conditions such as content percentages and molecular weight, to enhance stability, compatibility, and handleability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polycarbonate polyol is used to improve heat resistance, weather resistance, and hydrolysis resistance, then durability is improved, but viscosity increases and handleability deteriorates
Solution Approach 1:
The polycarbonate polyol is segmented into two distinct components: a low-viscosity polycarbonate polyol (viscosity 50-500 cP) and a high-viscosity polycarbonate polyol (viscosity 500-5000 cP). This segmentation allows the low-viscosity component to provide good handleability while the high-viscosity component contributes to durability, resolving the contradiction between ease of operation and reliability.
Solution Approach 2:
The invention changes the viscosity parameter of the polycarbonate polyol by introducing a distribution range (50-5000 cP) with specific weight average molecular weights. By controlling the viscosity within this range and specifying the molecular weight distribution, the composition achieves both low enough viscosity for good handleability and sufficient molecular weight for high durability.
2Ease of operation
If ether bond or ester bond is introduced into polycarbonate polyol to reduce viscosity, then handleability is improved, but color tone deteriorates
Solution Approach 1:
The invention applies local quality by introducing ether bonds or ester bonds only in specific portions of the polyol structure rather than throughout the entire molecule. The low-viscosity component (50-500 cP) contains these modified bonds strategically positioned to reduce overall viscosity while minimizing their impact on color tone, thus achieving good handleability without significant color deterioration.
3Ease of operation
If transesterification reaction is performed to produce copolymerized polycarbonate diol, then viscosity is reduced, but color tone and compatibility deteriorate
Solution Approach 1:
The invention creates a composite polyol composition by combining low-viscosity polycarbonate polyol (50-500 cP) and high-viscosity polycarbonate polyol (500-5000 cP) in specific ratios. This composite approach achieves the desired viscosity reduction without relying on transesterification reactions that cause coloration, while maintaining good compatibility with other polyols and solvents through careful composition design.
Data Source
AI summary
A polycarbonate diol composition comprising a repeating structural unit represented by the following general formula (I), further comprising at least one repeating structural unit selected from the group consisting of repeating structural units represented by the following general formulas (II) to (IV), and satisfying specific conditions.