Anionic Comb Copolymers for High-Concentration Pigment Dispersions
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Solution Overview
Problem
Current polymeric dispersants fail to simultaneously disperse organic pigments in high concentrations above 40% by weight with low viscosity, maintain reproducible color strength, prevent reagglomeration, and avoid foaming, while also being environmentally friendly due to the presence of alkylphenol residues that harm aquatic organisms.
Innovation Solution
Anionic comb copolymers are synthesized using polyethylene/polypropylene glycol mono(meth)acrylic acid esters with reactive terminal OH groups converted to anionic end groups, achieving a balanced EO/PO ratio for low viscosity and high pigment dispersion stability, avoiding the use of harmful alkylphenols.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional polymeric dispersants are used to disperse organic pigments in high concentrations, then pigment dispersion capability is improved, but viscosity increases and environmental harm occurs due to alkylphenol residues
Solution Approach 1:
The patent changes the chemical composition parameters of the dispersant by using anionic comb copolymers with specific monomer ratios (5-50% polyalkylene glycol mono(meth)acrylate, 50-90% aromatic vinyl monomer, 5-40% aliphatic vinyl monomer) and controlled molecular weight (10,000-100,000), eliminating alkylphenol residues while maintaining high pigment dispersion capability at concentrations above 40% by weight
Solution Approach 2:
The patent creates a composite polymer structure combining three types of monomers with distinct functions: polyalkylene glycol mono(meth)acrylate for hydrophilicity and solubility, aromatic vinyl monomer for pigment affinity, and aliphatic vinyl monomer for chain flexibility. This composite structure achieves both high pigment concentration dispersion and environmental compatibility
2Object-affected harmful factors
If polymeric dispersants are used to maintain low viscosity in high concentration pigment dispersions, then viscosity is reduced, but color strength reproducibility and anti-reagglomeration performance deteriorate
Solution Approach 1:
The patent optimizes multiple parameters simultaneously: molecular weight (10,000-100,000), monomer composition ratios, and anionic group content (0.5-5.0 mmol/g), creating a narrow parameter window that achieves the balance between low viscosity and reliable color strength reproduction in high concentration dispersions
Solution Approach 2:
The patent creates local functional zones within the polymer chain: hydrophilic polyalkylene glycol side chains for water solubility and viscosity control, aromatic vinyl segments for pigment surface affinity and color strength, and aliphatic vinyl segments for chain flexibility and anti-reagglomeration performance
3Quantity of substance
If conventional dispersants are used to disperse pigments, then dispersion capability is achieved, but foaming occurs in the dispersions
Solution Approach 1:
The patent changes the surface-active properties of the dispersant by using anionic comb copolymers with controlled hydrophilic-lipophilic balance (HLB) through specific polyalkylene glycol content (5-50%) and aromatic vinyl monomer content (50-90%), achieving effective pigment dispersion while minimizing foaming through optimized amphiphilic structure
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 anionic comb copolymers effectively disperse organic pigments in high concentrations with low viscosity, maintaining stable color strength and compatibility, and preventing agglomeration and foaming, while being environmentally friendly by eliminating harmful residues.
Implementation Method 1
These dispersants, supported by suitable wetting agents, act as surface-active agents to promote the wetting of the pigments to be dispersed and facilitate the breaking up of agglomerates and aggregates
Implementation Method 2
act as surface-active agents to promote the wetting of the pigments to be dispersed
Implementation Method 3
obtainable by polymerizing the monomers (A), (B) and (C) to obtain nonionic copolymers which have reactive terminal OH groups on the polyoxyalkylene side chains
Data Source
AI summary
The invention relates to anionically modified copolymers that can be produced by the polymerisation of monomers (A), (B) and (C) to obtain non-ionic polymers with reactive terminal OH groups and by the subsequent reaction of the terminal OH groups to form anionic end groups. According to the invention, (A) is a monomer of formula (I), in which A represents C2 -C4 alkene and B represents a C2-C4 alkene that is different from A, R represents hydrogen or methyl, m is a number between 1 and 500, n is a number between 1 and 500, (B) is an ethylenically unsaturated monomer containing an aromatic group and (C) is an ethylenically unsaturated monomer containing an alkyl radical.