Solvent-Free Polyester Latex Emulsification via Melt Mixing
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Solution Overview
Problem
Current methods for producing polyester resin emulsions for toners are time-consuming, energy-intensive, and environmentally unfriendly due to the use of solvent-based batch processes, which result in incomplete conversion and the need for additional processing steps to remove coarse material.
Innovation Solution
A solvent-free continuous process involving the contact of polyester resin with a solid neutralizing agent and surfactant, followed by melt mixing and de-ionized water addition to form a high-yield, low-coarse-content oil-in-water emulsion, allowing for continuous recovery of latex particles with minimal coarse content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If solvent-based batch processes are used to produce polyester resin emulsions, then the resin can be dissolved and emulsified, but the process becomes time-consuming and energy-intensive requiring subsequent distillation
Solution Approach 1:
The patent extracts and eliminates the organic solvent step from the traditional emulsification process. By using a solvent-free melt emulsification approach, the process directly emulsifies the polyester resin without requiring solvent dissolution and subsequent distillation, thereby removing the energy-intensive solvent recovery step while maintaining effective emulsification
Solution Approach 2:
The patent changes the physical state parameters of the emulsification process by operating in the melt state rather than dissolved state. The resin is emulsified directly from its melt form using controlled temperature and shear conditions, transforming the process from solution-based to melt-based emulsification, which eliminates solvent use and associated energy consumption
2Ease of manufacture
If solvent-based batch processes are used for emulsification, then resin can be processed, but the process requires large amounts of organic solvents that are not environmentally friendly
Solution Approach 1:
The patent removes organic solvents entirely from the emulsification process by employing a solvent-free melt emulsification method. This extraction of the harmful solvent component eliminates environmental contamination risks while preserving the core functionality of resin emulsification through alternative physical methods
Solution Approach 2:
The patent converts the challenge of processing high-viscosity resin into an advantage by utilizing the resin's melt state directly. What was previously a processing difficulty (needing solvents to dissolve viscous resin) becomes the basis for a novel solvent-free approach, where the melt state itself is used as the processing medium
3Object-generated harmful factors
If solvent-free batch processes with neutralizing solution and surfactant are used, then resin can be emulsified without organic solvents, but coarse material remains un-emulsified requiring additional processing steps
Solution Approach 1:
The patent transitions from batch to continuous emulsification processing, maintaining the resin in a continuous melt state throughout the emulsification zone. This continuous action ensures complete emulsification of all resin material without leaving unemulsified coarse particles, eliminating the need for subsequent filtration or polishing steps
Solution Approach 2:
The patent performs preliminary thorough mixing and emulsification of the resin in the melt state before it solidifies. By ensuring complete emulsification occurs while the resin is in its plasticized, low-viscosity melt state, all particles are properly dispersed before cooling, preventing formation of unemulsified coarse material that would require later removal
4Manufacturing precision
If additional steps like filtration and ultrasonication are added to remove coarse material, then latex quality improves, but processing time and energy consumption increase
Solution Approach 1:
The patent employs continuous emulsification processing where the resin remains in motion and emulsified state throughout the processing zone, ensuring complete and uniform emulsification in a single pass. This continuous action produces high-quality latex directly without the need for intermittent filtration or ultrasonication steps that would add time
Solution Approach 2:
The patent performs the emulsification action preliminarily and thoroughly while the resin is in its most processable melt state, ensuring complete particle dispersion before cooling and solidification. This preliminary complete emulsification prevents formation of coarse unemulsified material, eliminating the need for subsequent quality-correcting steps
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 significantly reduces processing time and energy consumption, achieves high product yield, and eliminates the need for additional steps like filtration, resulting in a more efficient and environmentally friendly production of polyester latex for toners.
Implementation Method 1
contacting at least one polyester resin with a solid neutralizing agent such as ammonium hydroxide flakes, potassium hydroxide flakes, sodium hydroxide flakes, sodium carbonate flakes, sodium bicarbonate flakes, lithium hydroxide flakes, potassium carbonate flakes, organoamines, and combinations thereof, in the absence of an organic solvent to form a pre-blend mixture
Implementation Method 2
contacting the pre-blend mixture with a surfactant; melt mixing the mixture; contacting the melt mixed mixture with de-ionized water to form an oil in water emulsion
Data Source
AI summary
A process for making a latex emulsion suitable for use in a toner composition includes contacting a resin with a solid neutralizing agent in the absence of an organic solvent to form a mixture either via a co-feeding process or a pre-blend mixture, and adding a solid or aqueous surfactant to the pre-blend mixture or prior to melt mixing the mixture.