Polyurethane-Polyurea Dispersion Simultaneous Distillation
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Solution Overview
Problem
The conventional acetone method for producing polyurethane-polyurea (PU) dispersions is inefficient in terms of space-time yield, energy input, and product quality, failing to meet market requirements for high molecular weights and narrow particle size distributions, which are essential for advanced applications.
Innovation Solution
A method involving the simultaneous dispersion and distillation of isocyanate-functional prepolymers in organic solvents with controlled volumetric content, achieving a solvent-free PU dispersion with a narrow and uniform particle size distribution, and high molecular weights, using specific reactants and solvents like acetone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the conventional acetone method is used to produce PU dispersions, then the process is simple and well-established, but the space-time yield is low and energy input is high
Solution Approach 1:
The patent combines the dispersion step and the solvent removal (distillation) step into a single integrated process. Water is added to the polymer solution and simultaneous distillation occurs, merging two separate unit operations into one continuous process that increases productivity and reduces energy consumption compared to conventional sequential methods
Solution Approach 2:
The process maintains continuous operation by performing dispersion and distillation simultaneously in a single reactor system. The useful actions of dispersing the polymer and removing the solvent occur continuously without interruption or intermediate steps, maximizing space-time yield and energy efficiency
2Manufacturing precision
If the conventional acetone method is used, then the process is established and reliable, but the molecular weight and particle size distribution uniformity are insufficient
Solution Approach 1:
The patent changes the physical parameters of the process by conducting dispersion and distillation simultaneously under controlled conditions. This parameter change enables precise control over polymer particle formation, resulting in narrow particle size distributions and high molecular weight uniformity while maintaining high production efficiency
Solution Approach 2:
The process performs preliminary dispersion of the polymer in the presence of water before complete solvent removal occurs. This preliminary action establishes uniform particle size distribution early in the process, which is then maintained through the distillation phase, ensuring high manufacturing precision
3Manufacturing precision
If hydrophilic groups are increased to narrow particle size distribution, then particle size uniformity improves, but water resistance and waterproofness deteriorate
Solution Approach 1:
The patent extracts the solvent (acetone) from the system through simultaneous distillation during dispersion. This extraction approach allows the formation of uniform particles through controlled water addition without requiring excessive hydrophilic groups, thereby maintaining water resistance while achieving narrow particle size distributions
Solution Approach 2:
Water acts as an intermediary substance that enables particle dispersion and size control without permanently modifying the polymer's hydrophilic character. The simultaneous distillation removes excess water and solvent, leaving particles with controlled size distribution while preserving the polymer's inherent water resistance properties
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
This method significantly increases the space-time yield by 10-80% compared to conventional methods, producing PU dispersions with improved particle size uniformity and thickening ability, suitable for advanced applications in coatings and adhesives.
Implementation Method 1
simultaneous distillation of the organic solvent in a dispersion and distillation unit
Implementation Method 2
dispersion takes place by mixing water with the polymer solution
Data Source
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AI summary
The invention relates to a method for producing aqueous polyurethane-polyurea dispersions, aqueous polyurethane-polyurea dispersions produced by this method and their use to produce coating agents and adhesives.