High solid content aqueous white pigment paste
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Solution Overview
Problem
Existing aqueous white pigment pastes suffer from sedimentation and poor re-dispersibility, limiting their application in inkjet printing inks.
Innovation Solution
A high solid content aqueous white pigment paste comprising TiO2 powders, an anionic polyelectrolyte, charge regulator, and pH regulator, with a specific weight ratio and grinding process, enhances re-dispersibility and storage stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the solid content of TiO2 powders is increased to reduce packaging and transportation costs, then the efficiency and cost-effectiveness improve, but the sedimentation problem worsens and re-dispersibility deteriorates
Solution Approach 1:
The patent introduces an anionic polyelectrolyte as a mediating substance between TiO2 particles to prevent sedimentation. The polyelectrolyte adsorbs onto particle surfaces, creating electrostatic repulsion that maintains suspension stability even at high solid contents (65-80 wt%), thus resolving the contradiction between high productivity and composition stability.
Solution Approach 2:
The patent changes the electrochemical parameters of the system by adding charge regulators and pH regulators. This modifies the surface charge characteristics of TiO2 particles, optimizing the zeta potential to enhance particle repulsion and prevent aggregation, thereby maintaining suspension stability at high concentrations.
2Stability of the object's composition
If more anionic polyelectrolyte is added to improve suspension stability, then the re-dispersibility improves, but the cost and complexity of formulation increase
Solution Approach 1:
The patent optimizes the dosage of anionic polyelectrolyte to a specific range (0.3-0.7 wt%) where maximum suspension stability is achieved. Beyond this range, additional polyelectrolyte provides diminishing returns while increasing formulation complexity and cost, thus resolving the contradiction between improved re-dispersibility and formulation 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 paste maintains high suspension stability with a zeta potential greater than 30 mV and surface tension above 60 mN/m, expanding its applicability and improving inkjet printing performance.
Implementation Method 1
the sedimentation problem of TiO2 powders (pigment) can be improved by adding a small amount of anionic polyelectrolyte
Implementation Method 2
the anionic polyelectrolyte, a charge regulator, and an pH regulator
Implementation Method 3
the paste maintains high suspension stability with zeta potential greater than 30 mV
Implementation Method 4
the TiO2 powders are surface-modified TiO2 powders. In one embodiment, the TiO2 powders are TiO2 powders modified with alumina
Data Source
AI summary
A high solid content aqueous white pigment paste includes: TiO2 powders; an anionic polyelectrolyte; a charge regulator; an pH regulator; and water. Herein, based on a total weight of the aqueous white pigment paste, the content of the TiO2 powders is 65 to 80 wt %, and a weight ratio of the TiO2 powders to the anionic polyelectrolyte ranges from 130 to 180.