Chiral Polyurea Rheology Modifier for Sag Control
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Solution Overview
Problem
Conventional rheology control agents in coating compositions often require high amounts to achieve desired rheological properties, leading to issues like haze and discoloration, and do not provide sufficient sag control, especially at low shear conditions.
Innovation Solution
A polyurea compound is synthesized by reacting polyisocyanates with a mixture of non-chiral and chiral mono-amines, where 2-98 mole % of the mono-amines are chiral, resulting in a more efficient rheology modification agent that reduces the amount needed and improves optical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high amounts of conventional rheology control agents are used to achieve desired rheological properties, then sag control is improved, but optical appearance deteriorates due to haze and discoloration
Solution Approach 1:
The invention changes the chemical composition parameters of the rheology control agent by incorporating chiral mono-amines (2-98 mole %) into the polyurea compound. This compositional parameter change enables achieving the same or better sag control performance at lower concentrations, thereby avoiding the optical defects (haze and discoloration) that occur with high amounts of conventional agents.
Solution Approach 2:
The invention creates a composite polyurea compound by reacting polyisocyanates with a mixture of chiral and non-chiral mono-amines. This composite structure combines the rheology modification capabilities of conventional polyurea compounds with the enhanced performance characteristics provided by chiral mono-amine units, achieving superior sag control at reduced concentrations.
2Reliability
If high amounts of conventional rheology control agents are used to achieve desired viscosity at low shear, then sag control is improved, but the amount of substance required increases leading to higher costs
Solution Approach 1:
The invention modifies the molecular structure parameters of the rheology control agent by incorporating chiral mono-amine units, which create more efficient intermolecular interactions. This structural parameter change increases the rheological activity per unit mass, enabling achievement of target viscosity at low shear with significantly reduced amounts of the compound.
Solution Approach 2:
The invention effectively replaces expensive conventional polyurea compounds with a more efficient formulation that requires smaller quantities. The chiral mono-amine based polyurea compound acts as a high-performance alternative that reduces material consumption while maintaining or improving performance.
3Ease of manufacture
If conventional polyurea compounds based on non-chiral mono-amines are used, then manufacturing cost is reduced, but rheology modification efficiency is insufficient requiring higher amounts
Solution Approach 1:
The invention changes the stereochemical parameters of the amine component from non-chiral to predominantly chiral (2-98 mole %). This stereochemical parameter change fundamentally alters the molecular packing and intermolecular interactions, resulting in enhanced rheology modification efficiency that maintains cost-effectiveness while improving performance.
Solution Approach 2:
The invention introduces local chiral centers within the polyurea compound structure by incorporating chiral mono-amine units. These localized chiral structures create specific spatial arrangements that enhance intermolecular interactions and rheological performance, improving efficiency without requiring complete structural redesign.
4Device complexity
If conventional rheology control agents are used, then formulation simplicity is maintained, but high-temperature flow properties are insufficient resulting in poor surface quality
Solution Approach 1:
The invention modifies the thermal-rheological parameters of the coating system by incorporating chiral mono-amine based polyurea compounds. The chiral structures provide temperature-dependent conformational changes that enhance flow properties at high temperatures, improving surface quality without complicating the formulation approach.
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 polyurea compound significantly decreases compliance values in sag simulation tests, enhances viscosity at low shear, and improves high-temperature flow, resulting in smoother, more glossy coatings with reduced haze and cost savings.
Implementation Method 1
reacting one or more polyisocyanates with one or more non-chiral mono-amines and one or more chiral mono-amines
Implementation Method 2
co-precipitating the reaction products to form the polyurea compound
Data Source
AI summary
A polyurea compound obtainable by reacting one or more polyisocyanates with one or more non-chiral mono-amines (I) and one or more chiral mono-amines (II) and co-precipitating the reaction products to form the polyurea compound, wherein 2-98 mole % of the mono-amines in the polyurea compound are chiral mono-amines. The invention also relates to the use of said polyurea compound as a rheology modification agent, in particular as sag control agent (SCA) in coating compositions. The invention further relates to sag control agent compositions, coating compositions and coatings comprising the polyurea compound as sag control agent.