Solvent-Free Emulsification for Toner Production
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Solution Overview
Problem
Current toner production processes, particularly those using solvent-based emulsion aggregation, face challenges such as environmental unfriendliness, high production costs, and difficulties in achieving small particle sizes due to the use of organic solvents and high surfactant concentrations, which affect the quality and efficiency of toner production.
Innovation Solution
A solvent-free emulsion process involving melt mixing of a resin with a surfactant and a neutralizing agent, followed by homogenization to form a latex dispersion with controlled particle sizes, which eliminates the need for organic solvents and reduces surfactant trapping, thereby improving toner quality and environmental sustainability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If solvent-based emulsion aggregation is used to prepare toners, then the resin can be easily dissolved and emulsified, but the process becomes environmentally unfriendly, requires expensive waste treatment and solvent recovery, and takes a long time to complete due to solvent evaporation
Solution Approach 1:
The invention extracts and removes the harmful organic solvent component from the emulsification process. By using solvent-free extrusion emulsification, the process eliminates ketones or alcohols that cause environmental harm and require expensive waste treatment, while maintaining effective resin emulsification through mechanical extrusion forces
Solution Approach 2:
The invention changes the physical parameters of the emulsification process by transitioning from a solvent-based chemical process to a solvent-free mechanical extrusion process. This parameter change eliminates the need for solvent evaporation time and reduces environmental harm while maintaining manufacturing effectiveness
2Ease of manufacture
If high surfactant concentration is used in solvent-free extrusion emulsification to emulsify crystalline polyester resin, then the resin can be successfully emulsified, but excess surfactant is trapped in the toner particle leading to significant difficulties with toner washing and higher triboelectric charge
Solution Approach 1:
The invention changes the surfactant concentration parameter from high levels to optimized lower levels (0.1-5% by weight of resin). This parameter change, combined with the extrusion emulsification method, achieves effective emulsification of crystalline polyester resin while preventing excess surfactant trapping, thereby improving toner washing properties and reducing triboelectric charge
Solution Approach 2:
The invention replaces the chemical action of high surfactant concentration with a mechanical extrusion system. The extrusion emulsification process uses mechanical forces to emulsify the resin with minimal surfactant, eliminating the problem of excess surfactant trapping that occurs with chemical emulsification methods
3Device complexity
If traditional rotor-stator homogenizers are used to prepare emulsions, then the process is simple, but the achievable particle size is not as small as with media mills or high-pressure homogenizers
Solution Approach 1:
The invention replaces traditional rotor-stator homogenizers with an extrusion emulsification system that uses a reciprocating piston and die arrangement. This mechanical substitution generates intense shear forces and cavitation during the extrusion process, achieving nanoscale particle sizes (50-500 nm) while maintaining process simplicity and eliminating the need for complex multi-stage homogenization equipment
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 process achieves toner particles with a unimodal or bimodal particle size distribution in the nanoscale to microscale range, enhancing toner production efficiency, reducing waste, and improving environmental friendliness while maintaining toner quality.
Implementation Method 1
flowing the melt composition to a reciprocating piston equipped with a dispersion apparatus comprising a die to form a latex dispersion
Implementation Method 2
homogenizing the mixture with a homogenizer to form an emulsion
Implementation Method 3
melt mixing a resin with at least one surfactant and at least one neutralizing agent
Data Source
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AI summary
Provided is an emulsion that includes a water phase and a resin containing phase. The emulsion is prepared from a mixture comprising water, a surfactant, a resin that includes an acidic moiety, and an organic compound having at least two different moieties. Each of the two moieties have a single functionality or dual functionality. The single functionality and the dual functionality are selected from a capability to neutralize the acidic moiety of the resin, a capability to form a hydrogen bond, or both.