Optically Active Polyurea Rheology Control Agents for Sagging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional rheology control agents in coating compositions are insufficient in achieving high viscosity at low shear and require high amounts, and they often discolor coatings, especially in polyol-isocyanate curing systems and radiation curing coatings, while also failing to provide effective sag control and clear, transparent coats.
Innovation Solution
The use of specific polyurea compounds formed by reacting optically active polyisocyanates with optically active monoamines or polyamines, which are not racemic mixtures and do not include optically active amino acids or their derivatives, to create rheology control agents that enhance viscosity build-up and sag control in coatings without affecting clarity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional rheology control agents are used to achieve high viscosity at low shear, then high amounts of the agent are required, but this increases the quantity of substance added to the coating composition and may affect coating clarity
Solution Approach 1:
The patent applies parameter changes by modifying the molecular structure of the rheology control agent through the use of optically active amines or isocyanates with specific chiral configurations. This structural parameter change results in significantly higher viscosity at low shear conditions, allowing effective sag control with much lower additive concentrations compared to conventional agents.
Solution Approach 2:
The invention creates composite molecular structures by reacting optically active components to form polyurea compounds with specific stereochemical properties. These composite structures exhibit enhanced thixotropic behavior and viscosity building characteristics, enabling high performance at low concentrations without compromising coating clarity.
2Stability of the object's composition
If conventional rheology control agents are used to control sagging, then sufficient sag control can be achieved, but the coating clarity and transparency are compromised due to discoloration
Solution Approach 1:
The patent utilizes parameter changes in the chemical structure of the rheology control agent by incorporating optically active amines or isocyanates with specific chiral centers. This structural modification produces agents that maintain coating clarity and transparency while providing effective sag control, eliminating the discoloration problem associated with conventional agents.
Solution Approach 2:
The invention employs specially designed polyurea compounds that perform their sag control function effectively and then remain transparent in the cured coating. These agents essentially 'disappear' optically after performing their rheological function, unlike conventional agents that leave visible residues or cause discoloration.
3Temperature
If conventional rheology control agents are used, then some viscosity build-up can be achieved, but the rate of viscosity build-up is insufficient for effective sag control
Solution Approach 1:
The patent applies parameter changes by modifying the molecular architecture through the use of optically active components, which creates polyurea compounds with enhanced thixotropic properties. This structural parameter change accelerates the viscosity build-up rate, enabling rapid sag control during the critical window after coating application.
4Stability of the object's composition
If high amounts of conventional rheology control agents are used to achieve desired rheological properties, then sag control improves, but the coating formulation complexity and the amount of additives increase
Solution Approach 1:
The patent resolves this contradiction by changing the molecular parameters of the rheology control agent through the use of optically active amines or isocyanates. This single parameter change in the agent's structure produces profound improvements in sag control performance, allowing effective formulations with minimal additive quantities and reduced formulation complexity.
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
These polyurea compounds significantly improve rheological properties, allowing for reduced usage while maintaining high viscosity at low shear, providing effective sag control and clear, transparent coatings, even at temperatures below 100°C, and are suitable for various coating applications.
Implementation Method 1
reacting one or more polyisocyanates with one or more optically active monoamines or by reacting one or more polyamines with one or more optically active monoisocyanates to form a poly-urea compound
Implementation Method 2
give thixotropic properties to a coating film when it is applied to the paint
Data Source
AI summary
The invention relates to the use as sagging controlling agent (SCA) in coating compositions of rheology control agents obtainable by reacting one or more polyisocyanates with one or more optically active amines or by reacting one or more polyamines with one or more optically active isocyanates. The invention also relates to rheology control agents obtainable as described above using specific polyisocyanates or polyamines. In addition the invention relates to the use of these rheology control agents in various applications.