Water-Based Ink Composition for Dense Printing 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 suffer from poor substrate-adhesion properties and insufficient image density, making it difficult to achieve high-quality printed materials on soft packaging.
Innovation Solution
A water-based ink formulation containing a pigment, a water-insoluble polymer dispersant, and a specific amount of dipropylene glycol monomethyl ether in the water-soluble organic solvent, with a solvent content between 29% to 35% by mass and dipropylene glycol monomethyl ether content between 75% to 96% by mass, enhances substrate-adhesion and image density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional water-based ink is used for ink-jet printing on low-liquid absorbing printing medium, then the ink is environmentally friendly, but the substrate-adhesion properties are poor and image density is insufficient
Solution Approach 1:
The patent changes the chemical composition parameters of the water-based ink by introducing a specific organic solvent (polypropylene glycol monoalkyl ether with HLB value of 7.0-7.5) and controlling its concentration (10-30% by weight), thereby improving substrate adhesion while maintaining environmental friendliness
Solution Approach 2:
The patent creates a composite ink system combining water, organic solvent, pigment, and resin in specific proportions, where the organic solvent acts as a bridge between the hydrophilic water-based system and the low-liquid absorbing substrate, achieving both environmental compatibility and reliable adhesion
2Object-affected harmful factors
If conventional water-based ink is used for ink-jet printing on low-liquid absorbing printing medium, then the ink is environmentally friendly, but the image density is insufficient
Solution Approach 1:
The patent optimizes the concentration parameters of the organic solvent (10-30% by weight) and pigment content to achieve sufficient image density while maintaining the water-based environmentally friendly composition
Solution Approach 2:
The organic solvent component replicates the wetting and penetrating capabilities of traditional organic solvents in inkjet printing, allowing the water-based ink to achieve similar image density on low-liquid absorbing substrates without the environmental drawbacks
3Ease of manufacture
If active energy ray-curable ink is used for printing on soft packaging, then printing can be achieved, but malodor is generated
Solution Approach 1:
The patent replaces the active energy ray-curable ink system with a water-based ink that uses evaporating organic solvent and resin formation mechanisms, eliminating the malodor generation issue while maintaining printing capability on soft packaging
Solution Approach 2:
The patent converts the potentially harmful malodor issue into a benefit by using a water-based system with controlled organic solvent evaporation, which provides printing capability without generating malodor, thereby improving both environmental compatibility and product quality
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 and maintains high image density on low-liquid absorbing printing media, ensuring high-quality printed materials.
Implementation Method 1
a water-based ink for ink-jet printing on a low-liquid absorbing printing medium, containing a pigment, a water-insoluble polymer dispersant, a water-soluble organic solvent and water
Implementation Method 2
a content of dipropylene glycol monomethyl ether (S1) in the water-soluble organic solvent is not less than 75% by mass and not more than 96% by mass
Implementation Method 3
droplets of ink are directly ejected from very fine nozzles and allowed to adhere to a printing medium
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 a polypropylene glycol monoalkyl ether; a content of the water-soluble organic solvent in the ink is 26 to 45% by mass; and a content of dipropylene glycol monomethyl ether (S1) in the water-soluble organic solvent is 70 to 98% 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.