Seeded Emulsion Polymerization for Stable Inkjet Latexes
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Solution Overview
Problem
Existing methods for producing latexes for aqueous inkjet ink compositions face challenges in achieving high quality while ensuring quick and efficient production without jetting instability, jetting latency, and nozzle clogging.
Innovation Solution
The method involves forming latexes by adding a monomer emulsion and initiator solutions in a controlled emulsification and polymerization process, reducing the need for surfactants and initiators, and achieving resin particles with specific size distributions and tunable glass transition temperatures, allowing for efficient and stable latex production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional polymerization processes are used to produce latexes, then production speed can be increased, but quality deteriorates with jetting instability, jetting latency, and nozzle clogging
Solution Approach 1:
The polymerization process is divided into two distinct stages: seed formation stage and particle growth stage. In the seed formation stage, resin seeds with controlled size are formed first. Then in the particle growth stage, monomers are polymerized on these seeds to grow particles to final size. This segmentation allows independent optimization of each stage to achieve both high productivity and high quality latexes without jetting issues
Solution Approach 2:
Resin seeds are formed in advance before the main particle growth process. The seeds serve as predetermined nucleation sites that control final particle size and distribution. By preparing seeds beforehand with specific properties (size, composition), the subsequent growth process can proceed quickly while maintaining uniform particle characteristics that prevent jetting instability and nozzle clogging
2Manufacturing precision
If multiple components (surfactants, initiators) are used in the polymerization process, then process control is improved, but manufacturing complexity increases
Solution Approach 1:
Traditional surfactants are completely removed from the system and replaced by reactive surfactants that are incorporated into the polymer chains themselves during polymerization. This extraction of external surfactants simplifies the component list while maintaining particle size control through the reactive surfactant functionality built into the polymer structure
Solution Approach 2:
The reactive surfactant serves multiple functions simultaneously: it acts as an emulsifier during polymerization, becomes part of the polymer chain structure, and provides surface activity for particle stabilization. This multi-functionality reduces the number of separate components needed while maintaining precise manufacturing control over particle characteristics
3Manufacturing precision
If production time is extended to achieve high quality latexes, then particle quality improves, but productivity decreases
Solution Approach 1:
The polymerization process maintains continuous useful action through the seeded approach where particle growth occurs continuously on pre-formed seeds without interruption. The reaction proceeds efficiently in a single continuous operation after seed formation, achieving narrow particle size distribution quickly because all particles grow simultaneously from identical seed starting points, eliminating the need for extended production times
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 highly stable latexes with narrow size distributions and tunable glass transition temperatures, enabling efficient production of high-quality latexes for aqueous inkjet ink compositions that facilitate coalescence at room temperature, improving printing performance.
Implementation Method 1
monomers undergo polymerization reactions to form resin seeds in the reaction mixture
Implementation Method 2
a first portion of a monomer emulsion comprising water, a monomer, an acidic monomer, a multifunctional monomer, and a first reactive surfactant
Data Source
AI summary
Methods for forming latexes are provided. In embodiments, such a method comprises adding a first portion of a monomer emulsion comprising water, a monomer, an acidic monomer, a multifunctional monomer, and a first reactive surfactant to a reactive surfactant solution comprising water and a second reactive surfactant to form a reaction mixture, wherein the reactive surfactant solution does not comprise monomers other than the second reactive surfactant; adding a first portion of an initiator solution to the reaction mixture so that monomers undergo polymerization reactions to form resin seeds in the reaction mixture; adding a second portion of the monomer emulsion to the reaction mixture comprising the resin seeds; and adding a second portion of the initiator solution to the reaction mixture to form a latex comprising resin particles.