Aqueous Ink Composition for Rub Fastness on Low-Absorption Media
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Solution Overview
Problem
Conventional water-based inks for ink-jet printing on low-liquid absorbing printing media, such as those used in soft packaging, fail to provide adequate rub fastness, which is essential for maintaining printed information integrity.
Innovation Solution
A water-based ink formulation containing a pigment, a polymer dispersant, diethylene glycol monoisopropyl ether, and at least one solvent selected from alkanediols or cyclic amides, with specific solvent content ranges, enhances ink wet-spreadability and film-forming properties to improve rub fastness on low-liquid absorbing media.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If water-based ink is used for ink-jet printing on low-liquid absorbing printing medium, then environmental burden is reduced compared to organic solvent-based ink, but rub fastness of printed material deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the water-based ink by incorporating specific organic solvents (glycol ethers, carboxylic acid esters, cyclic carbonates) in controlled amounts (5-50 mass%). This parameter adjustment allows the ink to achieve adequate rub fastness on low-liquid absorbing media while maintaining the environmental benefits of water-based formulation, resolving the contradiction between reduced environmental burden and improved reliability.
Solution Approach 2:
The patent creates a composite ink formulation combining water (main component), pigment, polymer dispersant, and specific organic solvents. This composite material approach allows the ink to exhibit properties that none of the individual components could achieve alone - specifically, the combination enables both water-based environmental friendliness and sufficient rub fastness through the synergistic effects of the multi-component system.
2Ease of manufacture
If conventional water-based ink formulation is used, then ease of manufacture is improved compared to organic solvent-based ink, but film-forming properties deteriorate leading to poor rub fastness
Solution Approach 1:
The patent modifies the formulation parameters by incorporating specific organic solvents (glycol ethers with 2-12 carbon atoms, carboxylic acid esters with 3-15 carbon atoms, cyclic carbonates with 3-7 carbon atoms) in optimized concentrations. These parameter changes improve film-forming properties and rub fastness while maintaining the water-based ease of manufacture, as the organic solvents enhance polymer coalescence and film continuity without requiring complex manufacturing processes.
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 rub fastness, ensuring printed materials remain intact even under mechanical stress, making it suitable for applications like food packaging.
Implementation Method 1
the water-soluble organic solvent contains diethylene glycol monoisopropyl ether (S1) and at least one solvent (S2) selected from the group consisting of an alkanediol having not less than 4 and not more than 6 carbon atoms and a cyclic amide compound
Implementation Method 2
A water-based ink formulation containing a pigment, a polymer dispersant, diethylene glycol monoisopropyl ether, and at least one solvent selected from alkanediols or cyclic amides, with specific solvent content ranges, enhances ink wet-spreadability and film-forming properties
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 diethylene glycol monoisopropyl ether (S 1) 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 diethylene glycol monoisopropyl ether (S1) in the water-soluble organic solvent is 40 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 rub fastness.