High Viscosity Latexes for Inkjet Inks
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Solution Overview
Problem
Existing aqueous inkjet ink compositions face challenges in achieving high viscosity and water-fastness due to the use of water-soluble resins, which can induce flocculation and reduce electrostatic stability, and also compromise the rub/mar-resistance of printed images.
Innovation Solution
The development of high viscosity latexes formed through unique formulations and processing steps, incorporating specific monomers such as styrene, acidic monomers, hydrophilic monomers, and reactive surfactants, without the need for water-soluble resins, resulting in resin particles with high glass transition temperatures and mechanical robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If water-soluble resins are added to tune viscosity and facilitate thin film formation, then film formation is improved, but flocculation and aggregation of resin particles occur and electrostatic stability is reduced
Solution Approach 1:
The patent removes water-soluble resins from the inkjet ink composition entirely, extracting the problematic component that caused flocculation and aggregation. The invention achieves film formation without relying on water-soluble resins by using a different binder system based on acrylic and vinyl acetate polymers with specific glass transition temperatures, thereby eliminating the trade-off between film formation and electrostatic stability
Solution Approach 2:
The patent changes the key parameter from using water-soluble resins to using polymers with controlled glass transition temperatures (Tg between -50°C and 0°C). This parameter change allows the binder to provide both viscosity control and film formation capabilities while maintaining electrostatic stability, as the specific polymer composition and Tg range prevent the flocculation issues associated with water-soluble resins
2Ease of operation
If water-soluble resins are added to facilitate thin film formation, then film formation is improved, but rub/mar-resistance of printed images is reduced
Solution Approach 1:
The patent extracts water-soluble resins from the composition to prevent the loss of rub/mar-resistance. By eliminating these resins and replacing them with a specific binder system based on acrylic and vinyl acetate polymers with controlled Tg, the invention achieves both thin film formation and improved mechanical durability of printed images
Solution Approach 2:
The patent uses a composite binder system comprising acrylic polymers and vinyl acetate polymers with specific glass transition temperatures. This composite material approach allows the binder to provide both the film formation properties needed for thin films and the mechanical strength for rub/mar-resistance, achieving a balance that water-soluble resins could not provide
3Ease of operation
If water-soluble resins are added to tune viscosity, then viscosity control is improved, but water-fastness of printed images is reduced
Solution Approach 1:
The patent removes water-soluble resins from the composition to eliminate the water-fastness problem. By using a binder system based on acrylic and vinyl acetate polymers with specific glass transition temperatures, the invention achieves viscosity control without compromising the water resistance of printed images, as these polymers do not have the same water-solubility issues as water-soluble resins
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 high viscosity latexes enable the formation of high-quality films with excellent rub/mar-resistance and water-fastness in aqueous inkjet ink compositions, eliminating the need for additional water-soluble resins and improving the overall printing performance.
Implementation Method 1
monomers of the monomer emulsion undergo polymerization reactions to form resin particles in a latex
Data Source
AI summary
Methods for forming latexes are provided. In an embodiment, such a method comprises adding a monomer emulsion comprising water, a monomer, an acidic monomer, a hydrophilic monomer, a difunctional monomer, a first reactive surfactant, and a chain transfer agent, to a reactive surfactant solution comprising water, a second reactive surfactant, and an initiator, at a feed rate over a period of time so that monomers of the monomer emulsion undergo polymerization reactions to form resin particles in a latex. The reactive surfactant solution does not comprise monomers other than the second reactive surfactant, the reactive surfactant solution does not comprise a resin seed, and the monomer emulsion does not comprise the resin seed. The latex is characterized by a viscosity in a range of from about 10 cP to about 100 cP as measured at a solid content of about 30% and at room temperature. The latexes are also provided.