Polyetheramide Synergist for Coating Viscosity Rebound
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Solution Overview
Problem
Existing silica-based rheology modifiers in coating formulations face challenges with high silica loading leading to poor in-can stability and adverse effects on coating properties like gloss and transparency, while also having slow viscosity rebound after shear stress, which affects sag behavior.
Innovation Solution
An organic polymer with a polyetheramide structure, comprising a polycarboxylic acid and polyamine linked by an amide bond, incorporating ethylene oxide units for enhanced solubility and interaction with silica particles, is used to improve low-shear viscosity and facilitate fast viscosity rebound without the need for volatile organic liquids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the dosage of silica particles is increased to enhance thixotropic effect and viscosity rebound, then low-shear viscosity and sag resistance are improved, but in-can stability deteriorates due to settling and coating properties like gloss and transparency are adversely affected
Solution Approach 1:
A polyetheramide synergist polymer is introduced as an intermediary substance that mediates between silica particles and the coating matrix. This synergist enhances the thixotropic effect and viscosity rebound by facilitating stronger non-covalent interactions among silica particles without requiring increased silica loading, thereby maintaining in-can stability and coating properties while achieving improved sag resistance
Solution Approach 2:
The invention creates a composite rheology modification system combining silica particles with polyetheramide synergist polymer. This composite approach allows the synergist to amplify the thixotropic effect of silica at lower silica concentrations, resolving the contradiction between achieving sufficient viscosity rebound and maintaining in-can stability by preventing silica settling
2Speed
If the dosage of silica particles is increased to achieve quicker viscosity rebound, then sag behavior is improved, but the speed of viscosity rebound is not well correlated with high low-shear viscosity and settling occurs
Solution Approach 1:
The polyetheramide synergist modifies the interaction parameters among silica particles by introducing additional functional groups that enhance hydrogen bonding and other non-covalent interactions. This changes the rheological parameters of the system, enabling faster viscosity rebound through strengthened particle networks at lower silica concentrations, thereby preventing settling while achieving quick rebound
3Stability of the object's composition
If existing hydroxyfunctional amide compounds or polyethyleneimine are used as synergists, then thixotropic effect is enhanced, but the viscosity rebound is not quick enough to effectively prevent sag or the additive is expensive with limited availability and involves toxic substances
Solution Approach 1:
The polyetheramide synergist features a modified molecular structure with polyether backbones and multiple hydroxyl groups that enhance solubility and interaction with silica particles. This structural parameter change enables faster viscosity rebound compared to conventional hydroxyfunctional amide compounds, achieving effective sag prevention within the required time frame
Solution Approach 2:
The polyetheramide synergist is designed to be cost-effective and readily available through conventional polymerization methods using common monomers. This provides an economical alternative to expensive polyethyleneimine, eliminating the need for specialized handling of toxic substances while achieving the required thixotropic enhancement and fast viscosity rebound for sag resistance
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 organic polymer effectively increases low-shear viscosity and enhances sag behavior by providing a fast viscosity rebound, thus improving coating application and stability without the drawbacks of high silica loading, such as settling and adverse effects on coating properties.
Implementation Method 1
They are effective in increasing low-shear viscosity and are widely used to improve sag resistance of a coating during the application process. Such effect is contributed by non-covalent interaction amongst silica particles and with other ingredients in a coating formulation, especially through hydrogen bonding interactions.
Implementation Method 2
The non-covalent interaction is disrupted under high-shear conditions but rebounds when shear force is removed or reduced. This feature is also known as thixotropic effect and it is essential for ease of coating application which happens at high shear and sag reduction after the application process.
Data Source
AI summary
Organic polymer of the structure (AmBn)-(C)x in which A is a polycarboxylic acid with two or more carboxylic groups, B is polyamine with two or more amine groups, m≥1, n≥1 and x=2-6; C has the structure F(D)y in which F is a urethane, amide and/or ester functional group, D is a C2 to C18 moiety with at least one primary, secondary and/or tertiary hydroxyl group(s) and y=1-6, characterized in that AmBn comprises 3 or more alkylene oxide units and 1 or more ethylene oxide units.