Toner Coalescence Using Coalescent Agents
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Solution Overview
Problem
Existing toner production methods require longer times and higher temperatures, which can lead to increased costs and variability in toner particle shape and size, affecting uniformity and performance.
Innovation Solution
An emulsion aggregation process that includes aggregating latex particles with wax and colorants, followed by the addition of a coalescent agent before coalescence, allowing for faster and lower-temperature processing to achieve more spherical and uniform toner particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional coalescence process is used without coalescent agent, then production time is longer and temperature is higher, but process is simpler
Solution Approach 1:
The coalescent agent is added to the mixture before the coalescence step, preparing the system in advance to facilitate faster and more efficient coalescence. This preliminary addition of the agent modifies the particle surface properties beforehand, enabling reduced coalescence time and temperature without requiring complex process changes.
Solution Approach 2:
The coalescent agent alters the physical-chemical parameters of the particle surfaces, reducing surface tension and enhancing coalescence efficiency. This parameter modification allows the coalescence process to proceed at lower temperatures and shorter times, directly improving productivity without significantly increasing process complexity.
2Productivity
If conventional coalescence process is used without coalescent agent, then production time is longer, but energy consumption is lower
Solution Approach 1:
The coalescent agent changes the surface energy parameters of the particles, reducing the activation energy required for coalescence. This enables the process to achieve faster coalescence rates at lower temperatures, thereby reducing overall energy consumption while improving production time.
Solution Approach 2:
The coalescent agent facilitates the phase transition from dispersed particles to coalesced droplets by modifying interfacial properties. This promotes more efficient mass transfer and coalescence kinetics, reducing both time and energy requirements for the phase transition process.
3Manufacturing precision
If conventional coalescence process is used, then toner particles have less uniform shape and size, but process is faster
Solution Approach 1:
The coalescent agent modifies surface tension and viscosity parameters during coalescence, enabling more uniform particle merging. This results in better spherical shape and size distribution while maintaining efficient coalescence rates, resolving the trade-off between precision and productivity.
Solution Approach 2:
The coalescence process with coalescent agent proceeds through distinct stages: initial aggregation, coalescence, and stabilization. This periodic progression allows uniform particle formation while maintaining overall process efficiency, achieving both high precision and productivity.
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 process reduces production time and temperature, resulting in toner particles with improved spheridization and uniformity, enhancing their geometric size distribution and circularity while maintaining performance characteristics.
Implementation Method 1
adding a coalescent agent prior to a coalescence step
Implementation Method 2
heating the mixture at a temperature below a glass transition temperature of said polymeric resin to aggregate said polymeric resin, colorant, and wax
Implementation Method 3
adding an organic or an inorganic acid to said mixture; optionally adding a polyion coagulant to said mixture
Data Source
AI summary
A process for preparing a toner includes mixing a polymeric resin emulsion, a colorant dispersion, and a wax to form a mixture; optionally adding a coagulant to the mixture; heating the mixture at a temperature below a glass transition temperature of the polymeric resin to aggregate the polymeric resin, colorant, and wax, to form aggregated particles; adding a coalescent agent to the aggregated particles; heating the aggregated particles and coalescent agent at a temperature above the glass transition temperature of the polymeric resin, to coalesce the aggregated particles to form toner particles, optionally cooling the mixture, and isolating the tone particles.