Encapsulated Particulate Solid via Borate Cross-Linking
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Solution Overview
Problem
Conventional dispersants for particulate solids in liquid media are ineffective in polar and non-polar ranges, often leading to flocculation due to displacement by stronger adsorbing materials, and are difficult to stabilize in media with organic solvents.
Innovation Solution
Encapsulating particulate solids with a cross-linked dispersant using a borate compound, where the dispersant has carboxylic acid groups and the cross-linking agent has epoxy groups, to create a stable encapsulated particulate solid colorant suitable for use in inks and paints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional dispersants are used to disperse particulate solid in liquid vehicle, then dispersion is achieved within a range of polarities, but the dispersant is readily displaced by more strongly adsorbing materials leading to flocculation
Solution Approach 1:
The invention uses a composite dispersant system comprising a polymeric dispersant with carboxylic acid groups cross-linked with a cross-linking agent having epoxy groups. This composite structure creates a cross-linked polymer coating on the particulate solid surface that provides both strong adsorption (through carboxylic acid-carboxylate interactions) and versatility across different polarity ranges (through the cross-linked network structure), preventing displacement by other adsorbing materials.
Solution Approach 2:
The invention changes the chemical parameters of the dispersant system by introducing cross-linking between carboxylic acid groups and epoxy groups. This cross-linking transforms the dispersant from a simple adsorbed layer into a stable cross-linked polymer coating, fundamentally changing the adsorption strength and stability parameters to prevent displacement while maintaining broad polarity adaptability.
2Device complexity
If cross-linking is performed without borate compound to simplify the process, then fewer chemicals are used, but the cross-linking efficiency and stability are reduced
Solution Approach 1:
The borate compound acts as an intermediary catalyst in the cross-linking reaction between carboxylic acid groups and epoxy groups. It facilitates the formation of stable cross-linked bonds without being consumed in the reaction, enabling efficient cross-linking under milder conditions and improving the overall stability of the encapsulated particulate solid while maintaining process simplicity.
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 process results in improved stability and dispersion of particulate solid colorants, particularly in ink jet printing inks, with reduced flocculation and aggregation, maintaining small particle sizes and optical density for high-quality prints.
Implementation Method 1
Conventional dispersants are adsorbed onto the surface of the particulate solid by physical interactions
Implementation Method 2
the dispersant then adsorbs onto the particulate solid surface and the dispersant can then be cross-linked via its cross-linkable groups utilising a cross-linking agent to 'fix' the dispersant onto the particulate solid
Implementation Method 3
the cross-linking is performed in the presence of a borate compound
Data Source
AI summary
A process for preparing an encapsulated particulate solid using an epoxy functional cross-linking agent and a carboxylic acid functional dispersant characterised in that the crosslinking is performed in the presence of a borate compound. The resultant solids are useful in, for example, ink jet printing inks where high optical density prints may be obtained.