Thixotropic Polyurea via Acoustic Vibration
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Solution Overview
Problem
Existing thixotropic polyurea compositions face challenges in achieving high thixotropic efficiency with minimal impact on optical and mechanical properties of cured coatings, often requiring carrier resins that may not be optimal for the final paint composition, leading to reduced formulation freedom and compatibility issues.
Innovation Solution
A process involving the reaction of polyisocyanate and mono-amine or polyamine in a liquid medium with acoustic vibration applied during or after the reaction to form polyurea particles, which are then precipitated, resulting in high thixotropic efficiency without the need for carrier resins and minimizing particle coarseness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If thixotropic polyurea compositions are prepared using conventional methods with carrier resins, then the thixotropic efficiency is improved, but the formulation freedom is reduced and compatibility issues arise due to unwanted resin components
Solution Approach 1:
The invention extracts and removes the carrier resin component from the thixotropic composition formulation. By preparing polyurea particles directly without requiring a carrier resin medium, the formulation eliminates unwanted resin components that previously constrained formulation freedom and caused compatibility issues in paint compositions.
Solution Approach 2:
The invention uses a liquid medium as an intermediary during the polyurea particle formation process. This liquid medium facilitates the reaction between polyisocyanate and amine to form polyurea particles, which are then precipitated. The liquid medium can be easily removed, leaving pure polyurea particles without carrier resin contamination.
2Manufacturing precision
If high concentration of SCA is used in master batch to achieve high thixotropic efficiency, then the thixotropic effect is enhanced, but the amount of carrier resin introduced into the paint recipe increases
Solution Approach 1:
The invention removes the carrier resin from the system entirely, allowing high concentrations of polyurea SCA to be incorporated into paint formulations without the accompanying burden of large amounts of carrier resin. This extraction enables high thixotropic efficiency while minimizing the quantity of unwanted resin introduced.
Solution Approach 2:
The invention creates a simplified version of the traditional master batch concept by forming polyurea particles directly in a liquid medium that can be easily removed. This approach copies the essential function of master batches (concentrated SCA delivery) without requiring the carrier resin vehicle that previously necessitated high resin amounts in paint recipes.
3Adaptability or versatility
If polyurea particles are formed without carrier resin, then the formulation freedom is improved, but the particle coarseness increases which affects coating appearance
Solution Approach 1:
The invention applies acoustic vibration (ultrasound) during the polyurea particle formation and precipitation process. This mechanical vibration energy prevents particle coarseness by keeping particles dispersed and fine during formation, ensuring good coating appearance while maintaining formulation freedom without carrier resin.
Solution Approach 2:
The invention employs periodic acoustic vibration treatment during the particle formation process. This periodic application of ultrasonic energy continuously breaks up developing aggregates and maintains fine particle size distribution, preventing coarseness even as polyurea particles form and precipitate from the liquid medium.
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
The process achieves high thixotropic efficiency with reduced compliance and improved Hegman fineness, allowing for the use of polyurea compositions as master batches in paint formulations without introducing unwanted resin components, thereby enhancing sag resistance and coating appearance.
Implementation Method 1
acoustic vibration is applied during contacting of the reactants or, as a post-treatment, on the formed polyurea particles or both
Implementation Method 2
precipitating the polyurea to form polyurea particles
Data Source
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AI summary
The invention relates to a process for the preparation of a thixotropic composition comprising polyurea particles, said process comprising contacting and reacting in a liquid medium reactants to form a polyurea and precipitating the polyurea to form polyurea particles, wherein acoustic vibration is applied during contacting of the reactants or as a post-treatment on the formed polyurea particles or both. The invention further relates to a thixotropic composition obtainable by the process, in particular thixotropic composition comprising high amounts of polyurea particles and optionally a polymer resin having high thixotropic efficiency. The compositions can be used, in particular as a masterbatch, in preparation of i.a. coating compositions.