Polycarbonate diol composition
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Solution Overview
Problem
Polycarbonate polyol-based polyurethane resins require high solvent amounts for production and lack optimal low-temperature flexibility and durability, particularly in applications requiring strict physical properties.
Innovation Solution
A polycarbonate diol composition with a specific structure and melt viscosity range, incorporating a polycarbonate diol with a general formula (I) and (II), optimized to reduce solvent usage, enhance low-temperature flexibility, and improve oleic acid resistance and moist heat resistance, while maintaining high solid content film formability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polycarbonate polyol is used to improve heat resistance, chemical resistance, and hydrolysis resistance, then durability is improved, but viscosity increases and requires large amount of solvent
Solution Approach 1:
The patent changes the molecular structure parameters of polycarbonate diol by controlling the average number of repeats (n11) to be 12 or more and specifying the carbon atom count of R11 groups. This structural optimization reduces the melt viscosity to a specific range (1000-10000 mPa·s at 50°C), allowing the use of smaller solvent amounts while maintaining the durability benefits of polycarbonate polyol.
2Reliability
If polycarbonate polyol is used to improve heat resistance and chemical resistance, then durability is improved, but low-temperature flexibility is insufficient
Solution Approach 1:
The patent introduces local quality variation by specifying that R11 can be different hydrocarbon groups (aliphatic, aromatic, cyclic) with 2-20 carbon atoms, and by controlling the distribution of repeat units (n11 ≥ 12). This creates local structural diversity within the polymer chain that provides both durability (from polycarbonate segments) and low-temperature flexibility (from varied hydrocarbon group configurations).
Solution Approach 2:
The patent creates a composite molecular structure combining polycarbonate diol with specific hydrocarbon group configurations (R11) that have different properties. The combination of rigid polycarbonate segments providing durability and flexible hydrocarbon groups providing low-temperature performance creates a composite material effect at the molecular level.
3Quantity of substance
If solid content concentration is increased to reduce solvent usage, then solvent amount is reduced, but film formability deteriorates
Solution Approach 1:
The patent changes the viscosity parameter of the polycarbonate diol to a specific range (1000-10000 mPa·s at 50°C) through molecular structure optimization. This controlled viscosity allows the formulation of coating compositions with high solid content (reduced solvent) while maintaining adequate flow and film formability, as the optimized viscosity ensures proper coating application and film formation even at higher concentrations.
Data Source
AI summary
A polycarbonate diol composition comprising polycarbonate diol having a structure represented by the following general formula (I) and a polycarbonate structure represented by the following general formula (II), wherein melt viscosity at 50° C. is 1000 to 10000 mPa·s, and an average value of the number of repeats represented by n11 in the following general formula (I) is 12 or larger: