Inkjet-Printed Article Adhesion via Multivalent Salt Layer
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Solution Overview
Problem
Aqueous pigment-based inks used in high-speed digital inkjet printing on plastic substrates face issues with adhesion and drying due to humectants, leading to defects like mottle, coalescence, and intercolor bleeding, and result in poor lamination bond strength in flexible packaging materials.
Innovation Solution
An aqueous-based ink-receptive layer containing water-soluble salts of multivalent metal cations, polyvinyl alcohol or polyvinyl amine, and silica particles, combined with aqueous pigment-based inks having high water content and specific dihydroxy humectants, improves adhesion and eliminates the need for separate tie-layers, enhancing lamination bond strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If aqueous pigment-based inks containing traditional humectants are used for high-speed digital inkjet printing on plastic substrates, then printing speed and productivity are improved, but adhesion is poor and defects such as mottle, coalescence, and intercolor bleeding occur
Solution Approach 1:
The patent changes the chemical parameters of the ink formulation by replacing traditional humectants (like glycerol and diethylene glycol) with alternative humectants that have different molecular structures and properties. This parameter change allows the ink to maintain流动性 for high-speed printing while improving adhesion to plastic substrates and reducing printing defects
Solution Approach 2:
The patent uses composite ink formulations that combine multiple components including pigment particles, water, alternative humectants, and adhesion promoters. This composite approach creates an ink system that simultaneously achieves high-speed printability and strong adhesion to water-impermeable substrates
2Ease of operation
If aqueous pigment-based inks with high water content and traditional humectants are used, then ink流动性 is improved for high-speed printing, but lamination bond strength is poor
Solution Approach 1:
The patent modifies the chemical composition parameters of the ink by using alternative humectants with specific molecular weight and hydroxyl group configurations. This allows the ink to remain fluid during high-speed printing while creating a printed layer that forms strong bonds during the lamination process
Solution Approach 2:
The alternative humectants act as intermediary substances that bridge the water-based ink and the hydrophobic plastic substrate. These humectants provide both the necessary fluidity for inkjet deposition and the chemical functionality for strong adhesion and lamination bonding
3Object-affected harmful factors
If aqueous pigment-based inks are used on water-impermeable substrates, then environmental safety is improved compared to solvent-based inks, but ink wetting and adhesion are difficult
Solution Approach 1:
The patent changes the surface energy parameters of the ink formulation by incorporating alternative humectants with specific surface tension properties. This allows the environmentally safe aqueous ink to effectively wet and adhere to water-impermeable substrates without requiring harmful solvents
Solution Approach 2:
The alternative humectants serve as intermediary substances that facilitate the interaction between the aqueous ink and the hydrophobic substrate. These humectants reduce the interfacial tension and improve wetting while maintaining the environmental safety of the aqueous-based formulation
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 solution improves the adhesion of aqueous pigment-based inks to water-impermeable substrates, prevents defects, and strengthens lamination bonds without sacrificing high-speed printing quality and productivity.
Implementation Method 1
improves the adhesion of aqueous pigment-based inks to water-impermeable substrates
Implementation Method 2
an aqueous-based ink-receptive layer... comprises: (a) one or more water-soluble salts of a multivalent metal cation
Implementation Method 3
one or both of a polyvinyl alcohol and a polyvinyl amine, or a copolymer derived from a vinyl alcohol and a vinyl amine
Data Source
AI summary
An inkjet-printed article has an ink receptive medium with a substrate and an aqueous-based ink-receptive layer disposed thereon. The aqueous-based ink-receptive layer includes: (a) a water-soluble salt of a multivalent metal cation at 0.6-49 weight %; (b) one or both of a polyvinyl alcohol and a polyvinyl amine (or a copolymer derived from a vinyl alcohol and a vinyl amine) at 0.5-30 weight %; and optionally, (c) a crosslinking agent or (d) silica particles. The article also has an inkjet-printed image disposed on the aqueous-based ink-receptive layer, provided from one or more aqueous pigment-based inks, each of which has a) an anionically-stabilized pigment colorant; b) one or more water-miscible humectants at a total amount of 1-20 weight %, each of which has a carbon atom to oxygen atom ratio of at least 1.0:1.0 and only two hydroxy groups.