Toner Production via CO2 Desolvation and Surface Functionalization
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Solution Overview
Problem
Existing methods for producing toner particles using resin fine particles and carbon dioxide as a dispersion medium fail to consistently achieve sharp particle size distributions and high circularities due to instability issues related to the affinity of resin fine particles for both the resin solution and carbon dioxide.
Innovation Solution
A method involving mixing a resin, a colorant, and an organic solvent with a resin fine particle, forming a dispersion in a pressure container, and introducing carbon dioxide to extract the solvent, where the resin fine particle satisfies specific atomic percentage ratios of elements measured by X-ray photoelectron spectroscopy to maintain dispersion stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If resin fine particles are used as dispersants in carbon dioxide dispersion medium, then washing and drying steps can be eliminated reducing energy consumption and cost, but particle size distribution sharpness and circularity are insufficient due to weak affinity and poor dispersion stability
Solution Approach 1:
The patent modifies the chemical composition parameters of the resin fine particle surface by controlling the ratio of specific functional groups (carboxyl, hydroxyl, amino groups) to enhance affinity with both resin solution and carbon dioxide. This parameter optimization enables the particle to maintain dispersion stability throughout the desolvation process, achieving sharp particle size distribution without requiring washing and drying steps.
Solution Approach 2:
The patent creates a composite structure on the resin fine particle surface by incorporating multiple functional groups (carboxyl, hydroxyl, amino) in specific ratios. This composite functional group structure provides dual affinity - interacting with both the resin solution droplets and the carbon dioxide dispersion medium - thereby maintaining dispersion stability and achieving high manufacturing precision.
2Stability of the object's composition
If resin fine particles with affinity for carbon dioxide are used, then dispersion stability can be maintained during desolvation, but affinity for resin solution decreases resulting in poor droplet coverage and aggregation
Solution Approach 1:
The patent optimizes the surface functional group composition parameters of the resin fine particles, specifically controlling the ratios of carboxyl groups (3-15 mmol/g), hydroxyl groups (2-10 mmol/g), and amino groups (1-5 mmol/g). This parameter optimization creates a balanced affinity profile that maintains reliable droplet coverage while preserving dispersion stability during desolvation.
Solution Approach 2:
The patent applies different functional groups with different affinities to the surface of the resin fine particles. The carboxyl groups provide affinity for the resin solution, while the hydroxyl and amino groups enhance interaction with carbon dioxide. This local functional differentiation enables the particle to simultaneously perform droplet coverage and dispersion stabilization functions.
3Manufacturing precision
If conventional dispersants are used to achieve sharp particle size distribution, then washing and drying steps are required increasing energy consumption and production cost
Solution Approach 1:
The resin fine particles are designed to serve dual functions: as dispersants for achieving sharp particle size distribution and as agents that enable direct filtration without washing. The specific surface functional group composition allows the particles to maintain dispersion stability throughout the desolvation process, making the dispersion medium removable by simple filtration, thereby eliminating energy-consuming washing and drying steps.
Solution Approach 2:
The patent designs the resin fine particles with multi-functionality: they serve as dispersants for droplet stabilization, as affinity agents for both resin solution and carbon dioxide, and as filtration-friendly particles that do not require washing. This universal design achieves sharp particle size distribution while eliminating post-processing steps that consume energy.
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
This approach allows for the production of toner particles with sharp particle size distributions and high circularities by ensuring the resin fine particle's surface composition adapts to the fluctuating solubility parameter of the continuous phase, enhancing dispersion stability and solvent resistance.
Implementation Method 1
introducing carbon dioxide to extract the solvent
Implementation Method 2
extract the organic solvent in the droplet into the dispersion medium
Implementation Method 3
The dispersant covers the surfaces of the droplets of the resin solution to suppress the agglomeration and sedimentation of the droplets
Implementation Method 4
introducing carbon dioxide to extract the solvent
Data Source
AI summary
Provided is a method of producing a toner including the steps of: mixing a resin solution comprising a resin R, a colorant, and an organic solvent, a resin fine particle comprising a resin S containing an element α, and carbon dioxide to form a droplet having a surface covered with the resin fine particle; introducing carbon dioxide in a liquid state and pressurizing to extract the organic solvent in the droplet; and removing the extracted organic solvent together with the carbon dioxide to provide a toner particle. In the method of producing a toner, when the resin fine particle is treated with the carbon dioxide in a liquid state, a change in amount of the element α on the surface of the resin fine particle after the treatment as compared to the amount before the treatment falls within a specific range.