Pigment Paste Viscosity Control via Wetting Agents
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Pigment pastes with high solids content often have excessively high viscosity, making them difficult to process with conventional automatic mixing machines, leading to inconsistent color and potential contamination issues.
Innovation Solution
Incorporating a wetting agent, such as alkylphenol polyoxyethylene condensates or fatty alcohol ethoxylates, to reduce the viscosity of pigment pastes containing alkyd resin, allowing for a solids content of over 60% while maintaining a suitable viscosity for processing, typically between 0.1 to 8 Pas, and reducing the organic solvent content to less than 300 g/l.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the solids content of pigment paste is increased to reduce VOC content and improve logistics efficiency, then the viscosity of the paste increases excessively, making it difficult to process with conventional automatic mixing machines
Solution Approach 1:
A wetting agent is introduced as an intermediary substance to modify the interaction between pigment particles and the continuous phase. The wetting agent adsorbs at the pigment surface, reducing interfacial tension and preventing agglomeration, thereby maintaining low viscosity even at high solids content (up to 80% by weight).
Solution Approach 2:
The patent changes the chemical composition parameters of the paste by incorporating specific wetting agents (such as alkylphenol polyoxyethylene condensates or fatty alcohol ethoxylates) in optimized concentrations. This parameter modification allows the system to achieve both high solids content and processable viscosity simultaneously.
2Productivity
If conventional automatic mixing machines are used to process high viscosity pigment pastes, then insufficient drop shape is obtained, leading to color inconsistency and contamination
Solution Approach 1:
The wetting agent serves as a mediator that improves the flow characteristics of the pigment paste, enabling it to form proper drops during automated dispensing. This ensures consistent dosing and prevents contamination strings from forming during the mixing process.
3Ease of operation
If alkyd resins with low viscosity are used to maintain processability, then the resin is difficult to synthesize and becomes cost-intensive
Solution Approach 1:
Instead of modifying the alkyd resin itself (which would increase manufacturing complexity), a wetting agent is added as an external intermediary to achieve the desired viscosity reduction. This approach maintains the simplicity of alkyd resin synthesis while still achieving processable paste viscosity.
Solution Approach 2:
The patent uses commercially available wetting agents as inexpensive additives to achieve viscosity control, rather than investing in complex custom resin synthesis. The wetting agent provides a cost-effective solution to the viscosity problem.
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 use of wetting agents in pigment pastes with alkyd resin enables them to be flowable and pumpable, facilitating precise dosing and mixing, while maintaining a low VOC content and preventing settling, thus ensuring consistent color and compliance with environmental regulations.
Implementation Method 1
the selection of resin is an essential aspect for the practical applicability of pigment pastes... the function of which is to wet the pigments
Data Source
AI summary
Pigment paste comprises at least an organic solvent, at least a pigment, at least an alkyd resin with a viscosity of at least 5 Pas measured at -23[deg] C and shear rate of 100 per second, and at least a crosslinking agent, where the pigment paste: exhibits a viscosity of 0.1-8, preferably 0.3-1 Pas measured at 23[deg] C and a shear rate of 100 per second, and contains at least 60 wt.% of solid material. An independent claim is included for an antisettling agent comprising the pigment paste and at least a primary color.