Polymeric Dispersant System for Universal Pigment Stabilization
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Solution Overview
Problem
Existing aqueous pigment preparations face challenges in achieving universal dispersibility, high color strength, stability, and low viscosity, while avoiding the use of regulated dispersants that cause surfactant leaching and foaming, particularly in water-based coatings.
Innovation Solution
A combination of two polymeric dispersants, an anionic copolymer and a non-ionic copolymer, is used to stabilize inorganic and organic pigments, enhancing dispersibility and color strength with low viscosity, and minimizing foaming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional wetting and dispersing agents (e.g., APEOs, TSPEOs) are used to achieve good dispersion of pigment particles, then dispersibility is improved, but ecotoxicological compliance deteriorates due to regulatory restrictions
Solution Approach 1:
The patent changes the chemical parameters of dispersing agents by using polymers with specific molecular weight ranges (5,000-500,000 g/mol) and specific functional group compositions (carboxylic acids, sulfonic acids, phosphonic acids, and their esters/amides), replacing conventional surfactants to achieve both good dispersibility and regulatory compliance
Solution Approach 2:
The invention uses composite polymer structures combining hydrophobic segments (for pigment surface attachment) and hydrophilic segments (for water solubility), creating amphoteric or nonionic copolymers that provide universal dispersing capability for both organic and inorganic pigments while meeting environmental requirements
2Stability of the object's composition
If water-soluble surfactants are used to improve dispersibility, then pigment dispersion is enhanced, but surfactant leaching and foaming increase
Solution Approach 1:
The patent changes the molecular weight parameter to high ranges (5,000-500,000 g/mol) and uses polymeric structures instead of small molecule surfactants, which reduces leaching while maintaining dispersibility through steric stabilization mechanisms
Solution Approach 2:
The invention replaces persistent small-molecule surfactants that accumulate and cause foaming with polymeric dispersants that remain bound to pigment surfaces, reducing free surfactant in the system that could cause leaching and foaming issues
3Quantity of substance
If high pigment content is achieved in aqueous preparations, then color strength is improved, but viscosity increases and stability deteriorates
Solution Approach 1:
The patent changes the dispersant concentration parameter and molecular weight to optimize the balance between pigment content and viscosity, using sufficient dispersant to maintain low viscosity even at high pigment concentrations (up to 80 wt% or more)
Solution Approach 2:
The invention creates local stabilization zones around each pigment particle through adsorbed polymer chains, preventing particle-particle interactions that would lead to flocculation and viscosity increase, enabling high pigment content with maintained flowability
4Device complexity
If universal dispersing agents are used for both organic and inorganic pigments, then formulation simplicity is improved, but optimization for specific pigment types deteriorates
Solution Approach 1:
The patent creates universal dispersants with amphoteric or nonionic character that can interact with both polar (inorganic) and non-polar (organic) pigment surfaces through their dual hydrophobic-hydrophilic structure, eliminating the need for separate dispersant systems
Solution Approach 2:
The invention adjusts polymer parameters including molecular weight, functional group composition, and amphiphilic balance to create a dispersant system that adapts to different pigment types while maintaining universal applicability, optimizing performance across pigment categories
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 combination of polymeric dispersants achieves stable, universal formulations with improved dispersibility, high color strength, and low foaming, while avoiding regulated dispersants, ensuring long-term storage stability and compatibility with various application media.
Implementation Method 1
specific surface-active substances such as wetting and dispersing agents must be used to modify the surface chemistry and enable good dispersion of the pigment particles
Implementation Method 2
the wetting and dispersing aids used enable good steric and/or electrostatic stabilization of the dispersed particles in these application media
Implementation Method 3
the wetting and dispersing aids used enable good steric and/or electrostatic stabilization of the dispersed particles in these application media
Implementation Method 4
at least one anionic copolymer as a dispersant, which contains (I) 40 to 95 mol% of structural units of an anionic monomer... and (II) 5 to 60 mol% of structural units of a monomer having repeating units according to formula (B1)... and (C) at least one nonionic copolymer which contains at least one structural unit with aromatic groups and at least one structural unit with polyethylene glycol groups
Data Source
AI summary
The present invention relates to aqueous pigment preparations comprising: (A) at least one organic and/or inorganic pigment and/or filler; (B) at least one anionic dispersant containing a copolymer which is formed from a mono/di-carboxylic acid-containing monomer and from a non-ionic water-soluble ethylenically unsaturated monomer; (C) at least one non-ionic polymeric dispersant comprising a block- and/or graft copolymer containing at least one organic, pigment-affinic group and at least one polyethylene glycol block. The aqueous pigment preparations are suitable for coloring inks, dyes, paints and architectural coatings.