Water-Based Inkjet Ink Adhesion on Low-Absorbent Media
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Solution Overview
Problem
Conventional water-based inks for ink-jet printing on low-liquid absorbing substrates face challenges with adhesion and image density, as they tend to be insufficient in substrate-adhesion properties and struggle to maintain high image quality.
Innovation Solution
A water-based ink formulation containing a pigment, a polymer dispersant, and a specific blend of water-soluble organic solvents such as propylene glycol monomethyl ether and 1,4-butanediol, optimized to provide improved wet-spreadability and adhesion by controlling the solvent content within specific ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional water-based ink is used for inkjet printing on low-liquid absorbing substrates, then the ink can be applied to the substrate, but the substrate-adhesion properties are insufficient and image density is low
Solution Approach 1:
The patent changes the chemical composition parameters of the water-based ink by incorporating specific water-soluble organic solvents (propylene glycol monomethyl ether and 1,4-butanediol) in optimized ratios. This parameter modification enables the ink to achieve both excellent substrate adhesion and high image density on low-liquid absorbing substrates, resolving the contradiction between adhesion properties and image quality
Solution Approach 2:
The patent creates a composite ink formulation by combining water, pigment, polymer dispersant, and specific water-soluble organic solvents in precise proportions. This composite material approach allows the ink to exhibit enhanced wet-spreadability and adhesion while maintaining high image density, simultaneously achieving both previously conflicting performance criteria
2Reliability
If gravure ink is used for soft packaging printing, then the ink can provide good coloration, but the ink contains organic solvents that pose environmental burden and the viscosity is too high for inkjet printing
Solution Approach 1:
The patent extracts and eliminates harmful organic solvents from the ink formulation by developing a water-based system. The resulting ink maintains good coloration quality while being environmentally friendly and suitable for food packaging applications, effectively removing the harmful factor without sacrificing performance
Solution Approach 2:
The patent fundamentally changes the solvent base parameter from organic to water-based, while adjusting the composition ratios of water, polymer dispersant, and water-soluble organic solvents. This parameter transformation enables the ink to achieve appropriate viscosity for inkjet printing while maintaining gravure-like coloration quality and eliminating environmental burden
3Reliability
If active energy ray-curable ink is used for soft packaging printing, then the ink can provide good printing properties, but the ink generates malodor that is problematic for food packaging
Solution Approach 1:
The patent extracts and eliminates the source of malodor by replacing active energy ray-curable components with water-based ingredients. The resulting ink maintains excellent printing properties including adhesion and image density while being odorless and safe for food packaging applications
Solution Approach 2:
The patent employs water-based organic solvents that evaporate completely without leaving harmful residues or odors. These volatile components provide the necessary printing performance temporarily during application, then disappear harmlessly, leaving only the pigment and binder on the substrate
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 ink achieves excellent substrate-adhesion properties while maintaining high image density, making it suitable for soft packaging applications like food packaging.
Implementation Method 1
the water-soluble organic solvent contains one or more (poly)propylene glycol alkyl ethers having a boiling point of not higher than 180°C
Implementation Method 2
a specific silicon-based surfactant
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 at least one solvent (S1) selected from the group consisting of propylene glycol monomethyl ether and propylene glycol monopropyl ether and at least one solvent (S2) selected from the group consisting of 1,4-butanediol, 1,6-hexanediol, dipropylene glycol and 2-pyrrolidone; a content of the water-soluble organic solvent in the water-based ink is 20 to 45% by mass; and a content of the solvent (S1) in the water-soluble organic solvent is 78 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 aforementioned ink. The water-based ink for ink-jet printing according to the present invention is capable of providing a printed material that is excellent in substrate-adhesion properties while maintaining high image density.