Stoichiometric Polyelectrolyte Primer for Inkjet Waterfastness
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Solution Overview
Problem
Inkjet printing technologies face challenges in achieving waterfastness and efficient inkjetting of polymer-based primer compositions due to high viscosity and slow drying, which affect print quality and reliability.
Innovation Solution
A method involving an aqueous primer composition with a stoichiometric polyelectrolyte complex, which is less viscous and soluble in solutions with salt, allowing for effective interaction with ink components and improved print quality, including the use of a polydiallyldimethylammonium polystyrenesulfonate complex, and a printing apparatus with primer and ink application units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If polymer compositions are used in primer to improve image quality and prevent ink coalescence, then optical color density and print stability are improved, but viscosity increases making the fluid difficult to jet
Solution Approach 1:
The patent changes the chemical parameters of the polymer by using copolymers with specific functional groups (carboxyl, hydroxyl, amine) and controlling molecular weight and composition ratios. This allows the primer to achieve both high polymer content for image quality and appropriate viscosity for jetting by modifying molecular structure rather than reducing polymer concentration
Solution Approach 2:
The patent creates a composite primer system combining multiple polymer components with complementary functions - one polymer provides adhesion and another provides pigment stabilization. This composite approach allows each component to be optimized independently for its function while maintaining overall fluidity for jetting application
2Manufacturing precision
If charged polymers are used to improve pigment destabilization and print quality, then optical color density is improved, but drying time increases which inhibits waterfastness
Solution Approach 1:
The patent optimizes the charge density and type of charged groups in the polymers, balancing electrostatic attraction for pigment stabilization with appropriate drying characteristics. By controlling the ratio of charged to uncharged segments and selecting specific charge types, the primer achieves effective pigment binding without excessive water retention that would slow drying and compromise waterfastness
Solution Approach 2:
The patent uses polymers that replicate the charge characteristics needed for pigment interaction while maintaining bulk properties suitable for rapid drying. The charged polymer segments effectively copy the electrostatic field needed for pigment destabilization and binding, while the overall polymer structure maintains appropriate water mobility for fast drying and waterfastness
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 method enhances waterfastness and print quality by stabilizing pigments and water-dispersible resins, enabling efficient inkjetting and reducing the need for organic solvents, while maintaining the solubility of the polyelectrolyte complex during drying.
Implementation Method 1
primer compositions normally contain compositions with acidic and/or electrophilic properties in order to destabilize pigment color particles
Implementation Method 2
stoichiometric PECs typically show a low solubility in water... solutions comprising a stoichiometric polyelectrolyte complex are less viscous than conventional polymer dispersions and therefore can be jetted effectively
Data Source
Figure 1
Figure 2A~2B
Figure 2C~3B
AI summary
The present invention relates to a method for applying an image onto the recording medium, the method including the step of applying a primer composition comprising a stoichiometric polyelectrolyte complex to a recording medium. The present invention further relates to a printing apparatus for carrying out said method.