Continuous Toner Coalescence Process
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional emulsion aggregation (EA) toner production processes are energy-intensive and time-consuming, with batch processes requiring long processing times and leading to fouling issues, which increase downtime and energy consumption.
Innovation Solution
A continuous process for coalescing toner particles involves heating an aggregated polyester particle slurry beyond its glass transition temperature, followed by quenching it below this temperature, using a heat exchanger system with a residence time reactor to achieve coalescence, and recovering the coalesced slurry, while capturing heat energy to reduce overall energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If batch processes are used for preparing toner, then toner can be produced through conventional emulsion aggregation, but processing time becomes very long (upwards of 10 hours) and energy consumption increases
Solution Approach 1:
The patent converts the batch process into a continuous process where toner slurry flows continuously through heated zones and cooling zones. The continuous circulation through heat exchangers enables uninterrupted coalescence action, eliminating the long idle ramp-up and cooling periods inherent in batch processing, thereby dramatically reducing processing time while maintaining manufacturing capability
Solution Approach 2:
The patent pre-heats the toner slurry to the glass transition temperature or above before the actual coalescence step. This preliminary heating prepares the system for rapid coalescence by eliminating the need to heat the entire batch from ambient temperature during the production cycle, thus reducing the overall processing time without sacrificing the conventional manufacturing approach
2Ease of manufacture
If batch processes are used for preparing toner, then conventional emulsion aggregation can be performed, but energy consumption becomes very high due to long heating and cooling cycles
Solution Approach 1:
The continuous circulation system allows the slurry to pass repeatedly through heating and cooling zones in an optimized sequence. Heat exchangers efficiently transfer thermal energy during each pass, and the continuous flow pattern eliminates the repeated heating-from-ambient cycles of batch processing, significantly reducing total energy consumption while maintaining conventional manufacturing capability
Solution Approach 2:
The patent changes the temperature parameters dynamically during the process - heating to glass transition temperature or above for coalescence, then rapidly cooling below glass transition temperature to freeze the structure. This parameter control optimizes energy usage by applying heat only when and where needed for the phase transition, rather than maintaining high temperatures throughout the entire batch cycle
3Temperature
If high jacket temperatures and low fluid velocity are used under stirring in batch reactors, then heating can be achieved, but fouling of reactor walls occurs necessitating additional cleaning downtime
Solution Approach 1:
The continuous flow system prevents fouling by maintaining constant motion of the slurry through the heat exchangers. The continuous circulation eliminates stagnant zones where fouling would occur, and the steady flow regime allows for more moderate temperature gradients that reduce the tendency for material to adhere to surfaces, thereby eliminating cleaning downtime while maintaining effective heating
Solution Approach 2:
The system transitions from static batch heating with localized hot spots to dynamic continuous flow heating. The slurry continuously moves through zones of controlled temperature, preventing the formation of fouling layers on heat transfer surfaces. The dynamic flow pattern ensures uniform heat distribution without the extreme temperature gradients that cause fouling in batch reactors
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 energy consumption, shortens production time, and enhances the consistency of the toner product by controlling temperature parameters, minimizing fouling and lot-to-lot variations.
Implementation Method 1
heating an aggregated polyester particle slurry beyond its glass transition temperature
Implementation Method 2
The particles coalesce to form a coalesced particle slurry
Implementation Method 3
quenching the coalesced particle slurry to a second temperature below the glass transition temperature
Implementation Method 4
heating an aggregated polyester particle slurry beyond its glass transition temperature in a first heat exchanger
Data Source
AI summary
Processes for continuously coalescing particles from an aggregated particle slurry are disclosed. An aggregated particle slurry is further heated in a first heat exchanger, and the heated slurry then flows through a residence time reactor. The slurry, now containing coalesced particles, then flows through a second heat exchanger and is quenched. The recovered coalesced particle slurry is then suitable for washing and drying. No moving parts are needed in this system.