Comb Polyurethane Dispersant for High Pigment Loading Ink
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Solution Overview
Problem
Existing ink compositions face challenges in achieving low viscosity, high pigment loading, and reduced milling times while maintaining pigment stability, which are not adequately addressed by conventional dispersants.
Innovation Solution
A comb polyurethane dispersant with oxamide diol groups is used, formed by reacting a diisocyanate with an oxamide diol, offering improved stability and viscosity reduction, enabling higher pigment loading and reduced milling times in ink and coating systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional dispersants are used in ink compositions, then pigment dispersion stability is maintained, but ink viscosity remains high and pigment loading is limited
Solution Approach 1:
The patent changes the chemical structure parameters of the dispersant by introducing oxamide diol groups with specific molecular weight ranges (500-5000) and functional group compositions. This structural parameter change enables the dispersant to achieve both high pigment loading capacity and stable dispersion, resolving the contradiction between stability and quantity.
Solution Approach 2:
The dispersant is formulated as a composite structure combining polyurethane backbone with oxamide diol functional groups. This composite material approach creates a dispersant that simultaneously provides steric stabilization and electrostatic repulsion, enabling high pigment loading while maintaining dispersion stability.
2Stability of the object's composition
If conventional dispersants are used, then pigment stability is maintained, but milling time is extended
Solution Approach 1:
The dispersant is pre-formed with optimized oxamide diol group structures before being added to the pigment dispersion. This preliminary preparation of the dispersant structure enables it to immediately and effectively adsorb onto pigment surfaces during milling, reducing the time required to achieve stable dispersion without compromising pigment stability.
Solution Approach 2:
By optimizing the molecular weight and functional group composition parameters of the oxamide diol-containing dispersant, the patent enhances the dispersant's affinity for pigment surfaces and its steric barrier effectiveness. This parameter optimization accelerates the dispersion kinetics, reducing milling time while maintaining pigment stability.
3Quantity of substance
If higher pigment loading is achieved, then ink composition becomes more concentrated, but viscosity increases
Solution Approach 1:
The patent utilizes parameter changes in the dispersant structure, specifically the molecular weight and functional group composition of oxamide diol-containing polymers. By optimizing these parameters, the dispersant provides enhanced steric stabilization that prevents pigment particle aggregation even at high loadings, thereby maintaining lower viscosity compared to conventional dispersants.
Solution Approach 2:
The oxamide diol-containing dispersant acts as an intermediary between pigment particles, providing steric barriers that prevent direct particle-particle contact. This intermediary action allows higher pigment concentrations to be achieved without the corresponding increase in viscosity that would normally result from particle aggregation and interaction.
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 comb polyurethane dispersant effectively stabilizes pigments, reduces viscosity, and increases pigment loading, resulting in improved print density and milling efficiency in ink and coating compositions.
Implementation Method 1
the pigment dispersion is generally stabilized by a dispersant which serves to prevent the pigment particles from agglomerating and settling out of the carrier
Implementation Method 2
improved pigment dispersion is still needed to further lower the ink viscosity
Data Source
AI summary
Embodiments described herein provide a dispersant for ink and pigmented coatings. The dispersant is a polyurethane having oxamide diol groups. The dispersant may be used to prepare a wide variety of inks and coatings having high pigment loading and existing within a conventionally-useful viscosity range.