Quaternized Comb Polymers for Dual-Solvent Dispersion Stability
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Solution Overview
Problem
Existing comb copolymers fail to provide excellent solubility in both aqueous and organic media, leading to long processing times and instability of pigment dispersions, especially during storage, which is crucial for applications like color filter production.
Innovation Solution
Copolymers are synthesized by reacting styrene with unsaturated monomers, amino polyalkylene glycol ethers, and additional compounds like aromatic carboxylic acids, amidoamines, and quaternary ammonium compounds, resulting in polymers that are highly soluble in both media and maintain low viscosity and stability even at elevated temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If comb copolymers with polyacrylate or polyester side chains modified with phosphoric acid ester groups, amine groups, or quaternary ammonium salts are used, then solubility in either aqueous or organic solvent systems can be adjusted, but solubility in both aqueous and organic media cannot be adequately achieved, leading to excessively long processing times
Solution Approach 1:
The patent applies local quality by creating a comb copolymer structure where different parts of the molecule have distinct functions: the polystyrene backbone provides organic solvent compatibility, while the grafted poly(ethylene oxide) side chains provide aqueous solubility. This local differentiation of properties within the same polymer molecule enables simultaneous solubility in both aqueous and organic media, resolving the contradiction between adaptability and processing time.
Solution Approach 2:
The invention creates a composite polymer structure combining polystyrene and poly(ethylene oxide) in a graft copolymer architecture. This composite material integrates the hydrophobic characteristics of polystyrene with the hydrophilic properties of poly(ethylene oxide), enabling the single polymer to function effectively in both aqueous and organic solvent systems, thereby eliminating the need for separate processing steps and reducing overall processing time.
2Ease of operation
If comb copolymers based on SMA resins with polyether side chains and amine oxide groups are used, then wetting properties are improved, but dispersion stability during storage is not always met
Solution Approach 1:
The patent applies parameter changes by modifying the chemical structure of the side chains from amine oxide groups to poly(ethylene oxide) groups. This structural parameter change fundamentally alters the polymer's interaction with pigment particles and solvent systems, providing both excellent wetting properties through the polyether chains and enhanced dispersion stability by creating a more robust steric barrier that prevents pigment aggregation during storage.
3Strength
If comb copolymers based on SMA resins with polyether side chains and amino groups converted to salts with unsaturated carboxylic acids are used, then adhesion properties are provided, but polymerisation during storage occurs leading to undesirable salification
Solution Approach 1:
The patent extracts the problematic amino groups that are prone to polymerisation and salification reactions, replacing them with poly(ethylene oxide) side chains. This extraction of the unstable functional groups eliminates the risk of polymerisation during storage while maintaining adhesion properties through the polar oxygen atoms in the polyether chains, which can form hydrogen bonds and interact with substrate surfaces.
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 resulting polymers exhibit superior solubility, stability, and tinting strength, significantly reducing viscosity and improving storage stability, making them suitable for universal tinting pastes and color resists.
Implementation Method 1
Copolymers are synthesized by reacting styrene with unsaturated monomers, amino polyalkylene glycol ethers, and additional compounds like aromatic carboxylic acids, amidoamines, and quaternary ammonium compounds
Data Source
AI summary
Suggested are new optionally quaternized comb polymer based on SMA or PS-PAA copolymers and their use as dispersants for lacquers and paints.