Carbonate Polyol Composition for Fast-Curing Heat-Resistant Polyurethane
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Solution Overview
Problem
Existing polycarbonate diols with phenolic hydroxy groups have slow reaction rates with isocyanate groups, leading to unsuitable polyurethane production, and existing aromatic polycarbonate diols lack sufficient mechanical characteristics and physical properties.
Innovation Solution
A carbonate group-containing polyol with a specific molecular structure and composition, including aromatic and aliphatic hydrocarbon groups linked by an ether bond, is developed to enhance mechanical characteristics such as breaking strength, breaking elongation, scratch resistance, and heat resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If phenolic hydroxy groups are used in polycarbonate diol, then heat resistance and weather resistance are improved, but reaction rate with isocyanate group becomes too slow for practical polyurethane production
Solution Approach 1:
The patent introduces a specific structural feature (aromatic cyclic structure linked through ether bond at specific position) to create local reactive sites with enhanced nucleophilicity. This allows the polymer to maintain overall heat resistance while having specific local regions that react rapidly with isocyanate groups, resolving the contradiction between bulk stability and reactive activity.
Solution Approach 2:
The patent changes the chemical structure parameters of the hydroxy groups by introducing specific aromatic cyclic structures linked through ether bonds. This structural modification alters the electronic properties and steric environment of the hydroxy groups, increasing their reaction rate with isocyanate while preserving the thermal stability provided by the aromatic core structure.
2Strength
If aromatic polycarbonate diol is used to improve mechanical characteristics, then breaking strength is enhanced, but other physical properties and mechanical characteristics become insufficient
Solution Approach 1:
The patent creates a composite molecular structure combining aromatic cyclic structures (for strength) with ether bond linkages and aliphatic hydrocarbon groups (for flexibility and elongation). This molecular-level composite structure delivers balanced mechanical characteristics including breaking strength, breaking elongation, adhesiveness, and scratch resistance, rather than excelling in only one property.
3Ease of manufacture
If polyester polyol is used as starting material, then ease of manufacture is improved, but hydrolysis resistance becomes poor
Solution Approach 1:
The patent extracts the problematic ester bond from the polymer backbone and replaces it with a carbonate group-containing structure. This removal of the hydrolysis-vulnerable ester linkage while retaining the manufacturability benefits of polyester synthesis methods resolves the contradiction between ease of production and hydrolytic stability.
4Ease of manufacture
If polyether polyol is used as starting material, then ease of manufacture is improved, but weather resistance and heat resistance become poor
Solution Approach 1:
The patent combines the ease of polyether polyol manufacture with aromatic cyclic structures that provide inherent weather and heat resistance. The resulting carbonate group-containing polyol maintains the processing advantages of polyether systems while gaining the environmental stability of aromatic structures, resolving the contradiction between manufacturability and durability.
Data Source
AI summary
Provided is a carbonate group-containing polyol comprising a constituent unit represented by the following formula (I), and having a melt viscosity of 500 to 200000 mPa·s at 50°C: wherein R1 is an organic group containing a) an organic group having two or more aromatic cyclic structures, and b) an optional aliphatic hydrocarbon group, and has at least one structure wherein the aromatic cyclic structure and the aliphatic hydrocarbon group are linked through an ether bond.