Core-Shell Resin Particles for Toner Particle Size Control
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Solution Overview
Problem
Existing methods for producing resin fine particles with carbon dioxide as a dispersion medium fail to achieve a good particle size distribution due to weak affinity of resin fine particles for the medium and solvent, leading to instability in toner particle formation.
Innovation Solution
Resin fine particles with specific partial structures A, B, and C are used, which are soluble or insoluble in certain organic solvents, and have specific solubility parameters to ensure affinity with carbon dioxide and resin solutions, maintaining stability and sharp particle size distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If resin fine particles are used as dispersing agents in carbon dioxide dispersion medium, then particle size distribution can be sharpened, but the resin fine particles exhibit weak affinity for the medium and resin solution, leading to poor segregation at the droplet/dispersion medium interface
Solution Approach 1:
The resin fine particles are designed with a core-shell structure where the core provides solvent resistance and the shell provides affinity for both carbon dioxide and resin solution. This local differentiation of properties allows the particles to simultaneously achieve sharp particle size distribution through effective interfacial segregation while maintaining reliability through dual affinity capabilities.
Solution Approach 2:
The invention uses composite resin fine particles comprising a core resin and a shell resin with different functional properties. The core resin provides solvent resistance while the shell resin provides affinity for carbon dioxide and resin solution, creating a composite material that resolves the contradiction between manufacturing precision and reliability.
2Manufacturing precision
If resin fine particles are used to maintain finely particulate state for dispersing function, then particle size distribution can be sharpened, but resistance to organic solvents is required which complicates the dispersing agent selection
Solution Approach 1:
The resin fine particles incorporate a core resin specifically selected for its solvent resistance properties, separating this function from the shell resin that provides interfacial affinity. This local functional differentiation simplifies the overall dispersing agent selection by providing a standardized core-shell structure that inherently meets both solvent resistance and affinity requirements.
3Manufacturing precision
If droplet viscosity is reduced by using higher temperature conditions to improve particle size distribution, then particle size distribution can be sharpened, but the resin fine particles do not have adequate resistance to organic solvent at these conditions
Solution Approach 1:
The core resin is specifically selected and designed to maintain its solvent resistance properties at elevated temperatures where droplet viscosity is reduced. This local functional specialization ensures that the core resin provides thermal and solvent stability while the shell resin facilitates interfacial segregation, allowing particle size distribution sharpening without sacrificing solvent resistance.
Solution Approach 2:
The composite core-shell structure allows the core resin to provide thermal and solvent stability at elevated processing temperatures while the shell resin maintains its affinity functions, resolving the contradiction between manufacturing precision at high temperature and reliability of solvent resistance.
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 method produces resin and toner particles with excellent solvent resistance and sharp particle size distribution, enhancing the quality and stability of toner formation.
Implementation Method 1
the dispersing agent must segregate to the interface between the droplet and the dispersion medium, and it is therefore crucial that the dispersing agent have affinity for both the resin solution and the dispersion medium
Implementation Method 2
the dispersing agent must segregate to the interface between the droplet and the dispersion medium
Implementation Method 3
methods that use carbon dioxide as a dispersion medium have been proposed in recent years
Data Source
AI summary
A method of producing a toner including the steps of: mixing resin fine particles, an organic solvent, and a resin R with a dispersion medium containing carbon dioxide, to prepare a dispersion of resin R-containing droplets; and removing the organic solvent by flowing carbon dioxide, wherein the resin fine particles contain one or more resins that have a partial structure A, B, and C, and are soluble in chloroform; the SP value of the partial structure A, the resin R, and the partial structure B satisfy particular relationships; a resin A constituted of the partial structure A and a resin B constituted of the partial structure B are soluble in the organic solvent; and a resin C constituted of the partial structure C is insoluble in the organic solvent.