Water-Based Ink Solvent Ratios for Clear Printing on Low-Absorbing Media
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Solution Overview
Problem
Conventional water-based inks for ink-jet printing on low-liquid absorbing printing media fail to achieve satisfactory image clarity and ejection stability, particularly in soft packaging applications, and there is a need for a solution that addresses these issues.
Innovation Solution
A water-based ink formulation containing triethylene glycol monobutyl ether and at least one solvent selected from alkanediol, 1,3-propanediol, or a cyclic amide compound, with specific solvent and solvent content ratios, along with a polymer dispersant and pigment, to enhance ejection stability and image clarity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional water-based ink is used for ink-jet printing on low-liquid absorbing printing medium, then the ink can be applied without organic solvents, but the image clarity and ejection stability are insufficient
Solution Approach 1:
The patent changes the chemical parameters of the water-based ink by incorporating specific organic solvents (glycol ethers, glycols, carboxylic acid compounds) and adjusting their content ratios. This modifies the ink's viscosity, surface tension, and drying characteristics, enabling both stable ejection and clear images on low-liquid absorbing media
Solution Approach 2:
The patent creates a composite ink formulation combining water, organic solvents, pigments, and resins in specific proportions. This composite structure leverages the benefits of each component: water as the base, organic solvents for solubility and ejection control, pigments for coloration, and resins for film formation, achieving both ejection stability and image clarity
2Manufacturing precision
If gravure printing with organic solvent ink is used for soft packaging, then good printing performance is achieved, but the working environment burden increases due to organic solvent content
Solution Approach 1:
The patent reduces the harmful impact by changing the solvent composition parameters - using water as the primary base with limited amounts of specific organic solvents (total organic solvent content controlled at 5-50 mass%). This maintains printing performance while reducing organic solvent emissions and environmental burden compared to conventional gravure inks
Solution Approach 2:
The patent extracts and removes the harmful excessive organic solvent component from the ink formulation, retaining only necessary amounts of specific organic solvents that provide functional benefits. This extraction of harmful elements allows the ink to achieve printing performance close to conventional inks while significantly reducing environmental burden
3Productivity
If active energy ray-curable ink is used for soft packaging printing, then printing speed and efficiency improve, but malodor generation becomes a problem
Solution Approach 1:
The patent removes the active energy ray-curable components and associated malodor-generating substances from the ink formulation. By extracting these harmful elements, the patent develops a water-based alternative that eliminates malodor generation while maintaining suitability for soft packaging applications
Solution Approach 2:
The patent adopts a simpler, more environmentally friendly ink composition that does not require complex curing systems. The water-based formulation with controlled organic solvents provides adequate printing efficiency without the need for active energy ray curing, eliminating the malodor problem associated with conventional curable inks
Data Source
AI summary
The present invention relates to [1] a water-based ink for ink-jet printing on a low-liquid absorbing printing medium, containing a pigment, a polymer dispersant, a water-soluble organic solvent and water, in which the water-soluble organic solvent contains triethylene glycol monobutyl ether (S1) and at least one solvent (S2) selected from the group consisting of an alkanediol having 4 to 6 carbon atoms, 1,3-propanediol and a cyclic amide compound, and a content of the solvent (S1) in the water-soluble organic solvent is 55 to 95% by mass, and [2] an ink-jet printing method including the step of printing characters or images on a low-liquid absorbing printing medium using the ink described in the above [1]. The water-based ink for ink-jet printing according to the present invention is excellent in ejection stability, and is capable of providing a printed material that is excellent in image clarity.