pH-Responsive Resin Particles for Ink Stability
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Solution Overview
Problem
Aqueous inkjet ink compositions face challenges with water-soluble resins causing flocculation and aggregation of resin particles, interfering with electrostatic stability and reducing water-fastness, and require additional additives for viscosity adjustment.
Innovation Solution
The development of pH-responsive resin particles polymerized from dioxane/dioxolane monomers, which exhibit size and viscosity changes with pH, allowing for synthesis at low pH and viscosity adjustment at higher pH without water-soluble resins or silica additives, and providing extended open-air stability and high glass transition temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If water-soluble resins are added to adjust viscosity, then viscosity control is improved, but resin particle stability deteriorates due to flocculation and aggregation
Solution Approach 1:
The patent applies parameter changes by utilizing pH-responsive resin particles that change their physical properties (size, viscosity) in response to pH changes. The resin particles are synthesized at low pH with low viscosity for easy handling, then the pH is increased to trigger expansion and viscosity increase, providing viscosity control without adding water-soluble resins that would cause flocculation.
Solution Approach 2:
The pH-responsive resin particles provide self-service by automatically adjusting the viscosity of the ink composition through their pH-triggered expansion. When pH is increased, the resin particles expand and increase viscosity inherently, eliminating the need for separate viscosity-adjusting additives and maintaining particle stability simultaneously.
2Ease of operation
If water-soluble resins are used for viscosity adjustment, then viscosity is improved, but water-fastness deteriorates
Solution Approach 1:
The patent uses parameter changes by employing pH-responsive resin particles that adjust viscosity through pH-triggered conformational changes rather than through water-soluble resins. This approach maintains the hydrophobicity and water-fastness of the printed image while achieving viscosity control through the pH-dependent expansion of the resin particles.
3Reliability
If high Tg resin particles are used for stability and reduced tackiness, then stability is improved, but adhesion and gloss differential deteriorate
Solution Approach 1:
The patent applies parameter changes by using pH-responsive resin particles with high glass transition temperatures that also exhibit pH-dependent expansion. The high Tg provides stability and reduced tackiness, while the pH-triggered expansion improves adhesion and reduces gloss differential by modifying the surface properties and flexibility of the resin particles at higher pH values.
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 pH-responsive resin particles enable ink compositions with improved stability, water-fastness, and reduced gloss differential, while eliminating the need for additional viscosity adjustment additives, resulting in enhanced printing performance and stability.
Implementation Method 1
the resin particles have a size that is pH dependent, including exhibiting a larger size at higher pH values. The viscosity of latexes comprising such resin particles is also pH dependent, including exhibiting a greater viscosity at higher pH values.
Implementation Method 2
Latexes for aqueous inkjet ink compositions are often synthesized through emulsion polymerization or microemulsion polymerization of hydrophobic monomers in water.
Implementation Method 3
water-soluble resins can induce flocculation and aggregation of resin particles as well as interfere with their electrostatic stability
Data Source
AI summary
Latexes are provided which may comprise water and resin particles comprising a polymerization product of reactants comprising a dioxane/dioxolane monomer and an additional monomer, wherein the dioxane/dioxolane monomer is an ester of (meth)acrylic acid with an alcohol comprising a dioxane moiety, an ester of (meth)acrylic acid with an alcohol comprising a dioxolane moiety, or both.