Crystalline Latex Particle Size Control via Neutralization Ratio
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Solution Overview
Problem
The existing phase inversion emulsification (PIE) processes for producing crystalline latex face challenges in controlling latex particle size due to variations in base concentration, leading to inconsistencies in toner production and increased energy usage, particularly when solvent reuse is involved.
Innovation Solution
A novel PIE process is developed, where a crystalline resin is dissolved in a mixture of solvents with a controlled neutralization ratio between 100% to 200%, specifically between 150% to 170%, to produce latex particles of uniform size less than 200 nm, using a formula that accounts for varying acid values and base concentrations, allowing for minimal size variability and improved toner quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If solvent reuse is implemented to reduce costs and disposal fees, then raw material savings and cost reduction are achieved, but latex particle size consistency deteriorates due to variations in base concentration from previous PIE processes
Solution Approach 1:
The patent applies preliminary action by measuring and adjusting the acid value of the resin before the PIE process and pre-calculating the required base amount based on this measurement. This allows accurate base dosing from the start, compensating for variations in reused solvents and ensuring consistent particle size despite solvent reuse conditions.
Solution Approach 2:
The patent implements feedback by measuring the actual acid value of the resin and using this measurement to calculate the precise base amount needed. This closed-loop approach ensures that base concentration is accurately controlled in each PIE process, maintaining particle size consistency even when reusing solvents from previous batches.
2Reliability
If base amount is increased to ensure complete neutralization, then neutralization ratio improves, but latex particle size variability increases due to over-neutralization
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the base amount based on the measured acid value of the resin. Instead of using a fixed base concentration, the formula adapts the base amount to match the actual resin acidity, ensuring complete neutralization without over-neutralization and maintaining consistent particle size across different batches.
3Adaptability or versatility
If acid value of crystalline resin varies between batches, then resin supply flexibility is maintained, but latex particle size consistency deteriorates without adjusted base amounts
Solution Approach 1:
The patent applies preliminary action by measuring the acid value of each resin batch before processing and using this measurement to pre-calculate the required base amount. This allows the process to adapt to varying resin acidity while maintaining consistent particle size control through adjusted base dosing.
Solution Approach 2:
The patent implements parameter changes by using the measured acid value to calculate and adjust the base amount in the PIE formula. This dynamic adjustment ensures that despite variations in resin acid value between batches, the latex particle size remains uniform and consistent.
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 approach results in uniform latex particles, enhancing print quality, reducing toner usage, and lowering energy consumption by maintaining consistent particle size and acid value ranges, thus improving the robustness of the PIE process.
Implementation Method 1
a first amount of base and water, where the amount of base neutralizes less than all of the acid groups present on the resin and is sufficient to form an emulsion
Implementation Method 2
adding water to convert the dispersion into an oil-in-water (O/W) dispersion
Implementation Method 3
converting the emulsion of step (b) into latex particles by the addition of water and mechanical mixing
Data Source
AI summary
A process for making a crystalline latex suitable for use in a toner by phase inversion emulsification (PIE) where when resin of particular acid number is neutralized to a certain degree, smaller sized resin particles are obtained reproducibly.