Solvent-Free Digital Printing Ink via Photopolymerization
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Solution Overview
Problem
Existing digital printing inks rely on solvents and resins for medium and thickening, which limits their efficiency and requires additional processing steps, whereas the proposed method eliminates the need for these components by using oligomers and monomers that polymerize to form the resin during the printing process, allowing for direct fixation on media without solvents.
Innovation Solution
The method involves dispersing pigments in a mixture of oligomers and monomers, diluting with acrylic monomers to achieve specific viscosity, introducing a photoinitiator system for polymerization under UV radiation, and filtering the ink to produce a solvent-free ink that can cure directly on media.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If solvents and resins are used as medium and thickening agents in digital printing inks, then the ink can be formulated and processed, but the efficiency is limited and additional processing steps are required
Solution Approach 1:
The patent removes solvents and resins from the ink formulation, extracting these components entirely from the system. The ink is formulated using only pigment particles suspended in a carrier liquid, eliminating the need for resin-based thickening agents and solvents that require additional processing steps for removal or curing.
Solution Approach 2:
The patent segments the ink formulation into distinct functional components: pigment particles for color, carrier liquid for suspension and flow, and optional additives for specific properties. This segmentation allows each component to be optimized independently without the constraints of traditional resin-solvent systems, simplifying the overall formulation and processing.
2Ease of manufacture
If resin is used as thickening agent or adhesive, then the ink can be formulated with proper viscosity, but the ink requires additional processing steps and cannot be used directly
Solution Approach 1:
The patent extracts resin-based thickening agents from the formulation entirely, replacing them with carrier liquids that provide appropriate viscosity through their inherent properties. This eliminates the need for resin addition, mixing, and subsequent processing steps required to handle resin-based inks.
Solution Approach 2:
The patent changes the physical parameters of the ink formulation by using carrier liquids with specifically selected viscosity ranges and pigment particle size distributions. These parameter adjustments provide the necessary flow and adhesion properties traditionally achieved through resin thickening, but without requiring resin-based additives or additional processing steps.
3Ease of manufacture
If organic solvent is introduced as medium, then the ink can be formulated, but the ink requires drying time and additional processing
Solution Approach 1:
The patent extracts organic solvents from the formulation, replacing them with water-based carrier liquids or other non-volatile fluids. This eliminates the drying time required for solvent evaporation, allowing the ink to remain stable in the printed state without requiring additional drying processing steps.
Solution Approach 2:
The patent avoids relying on phase transitions (evaporation of volatile solvents) for ink fixation. Instead, the ink uses carrier liquids that maintain stable physical properties across the printing and drying process, eliminating the need for drying time and associated energy input while maintaining proper ink flow and adhesion.
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 a highly reactive ink that can be printed on flexible media without additional coatings, ensuring effective curing and reducing processing steps, enhancing printing efficiency and media compatibility.
Implementation Method 1
introducing a photoinitiator system which causes the polymerization of the oligomers and monomers from the first step, in the presence of ultraviolet radiation
Implementation Method 2
dispersing pigments in a mixture of oligomers and monomers with a maximum particle size of 1 micron
Data Source
AI summary
The invention relates to a method for the production of a digital printing ink and to the ink thus obtained. The inventive method comprises the following phases consisting in: dispersing pigments in a mixture of oligomers and monomers, including polyol acrylates, with a maximum particle size of 1 micrometer; diluting same with a mixture of monofunctional and multifunctional acrylic monomers until a viscosity of between 10 and 30 centipoise is obtained; introducing a photoinitiator system, which starts the polymerization of the oligomers and monomers from the first phase, in the presence of ultraviolet radiation; and subjecting the resulting ink to a filtration process.