Polymer Polyol Synthesis via Melt Emulsification
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Solution Overview
Problem
The use of C—C unsaturated alcohol compounds as carriers for polymer polyols in radical polymerization often results in high viscosity products that are difficult to process, require time-consuming filtration due to the formation of large particles, and yield non-homogeneous products, making it challenging for standard applications, especially for hydrophobic polymer polyols needed in polyurethane coating applications.
Innovation Solution
A melt emulsification process is employed, which is a purely mechanical method that differs from radical polymerization, using stabilizers to maintain dispersion stability, and involves mixing melted thermoplastic styrene-acrylonitrile copolymers with polyols under shear to create small droplets, with specific stabilizers and polybutadiene diols to achieve stable and homogeneous polymer polyol dispersions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If radical polymerization is used to synthesize polymer polyols from C—C unsaturated alcohol compounds, then polymer polyol products are obtained, but the products exhibit high viscosity, form large particles requiring time-consuming filtration, and show non-homogeneous structure
Solution Approach 1:
The patent replaces the chemical radical polymerization process with a mechanical melt emulsification process. By using high-shear mixing and rotor-stator devices, the thermoplastic polymer is mechanically dispersed into the polyol carrier to form fine droplets (D50 < 10 µm) without chemical reaction, thereby avoiding the formation of large particles and high viscosity associated with radical polymerization
Solution Approach 2:
The patent changes the fundamental process parameter from chemical reaction (radical polymerization) to physical mechanical dispersion (melt emulsification). This parameter change transforms the synthesis approach, enabling the production of homogeneous polymer polyol dispersions with controlled particle size and reduced viscosity through mechanical energy input rather than chemical transformation
2Adaptability or versatility
If C—C unsaturated alcohol compounds are used as carriers for polymer polyols, then renewable raw materials are utilized, but side reactions during radical polymerization occur leading to high viscosity and difficult processing
Solution Approach 1:
The patent replaces chemical radical polymerization with mechanical melt emulsification, eliminating side reactions that occur during radical polymerization of C—C unsaturated compounds. The mechanical dispersion process avoids unwanted chemical reactions while maintaining the ability to use renewable polyol carriers, thereby improving manufacturing ease without sacrificing raw material flexibility
Solution Approach 2:
The patent extracts the problematic chemical polymerization step from the process and replaces it with purely mechanical dispersion. By removing the radical polymerization reaction entirely and using only physical mixing and emulsification, the harmful side reactions are eliminated while the beneficial use of renewable polyol carriers is preserved
3Productivity
If radical polymerization is used to produce polymer polyols, then polymerization occurs, but filtration is very difficult and time consuming due to formation of undesired larger particles
Solution Approach 1:
The patent replaces chemical polymerization with mechanical emulsification, which directly produces fine particle dispersions (D50 < 10 µm) suitable for injection molding without requiring filtration. The mechanical high-shear mixing and rotor-stator processing create uniformly dispersed droplets that eliminate the need for time-consuming filtration steps, thereby both increasing production rate and reducing time loss
Solution Approach 2:
The patent performs the dispersion action during the mixing and processing stages themselves, rather than as a separate post-processing step. The high-shear mixing and rotor-stator devices create the fine particle dispersion in-situ during manufacturing, eliminating the need for subsequent filtration operations and thereby reducing total process time
4Productivity
If radical polymerization is used in C—C unsaturated alcohol compounds, then polymer polyol is formed, but the product is not quite homogeneous
Solution Approach 1:
The patent replaces chemical radical polymerization with mechanical melt emulsification, which provides superior mixing and dispersion control. The high-shear mixing and rotor-stator devices create uniform droplet distributions throughout the polyol carrier, achieving homogeneous polymer polyol products (D10-D90 < 20 µm) that are more uniform than those obtained by radical polymerization
Solution Approach 2:
The patent uses dynamic high-shear mixing and rotor-stator processing to achieve uniform dispersion. The mechanical energy input and continuous mixing action during emulsification create homogeneous particle distributions, whereas static or less intensive mixing in radical polymerization leads to non-uniform products
Data Source
AI summary
The present invention relates to the synthesis of polymer polyols in unsaturated polyols as liquid phase, polymer polyols and their use.