Multilayered Structure for Water-Impermeable Inkjet Printing
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Solution Overview
Problem
High-speed digital inkjet printing systems face challenges in depositing water-based inks on water-impermeable substrates due to poor wetting and adhesion, leading to image quality issues like mottle, coalescence, and intercolor bleeding, especially when using substrates prone to wrinkling or melting at moderate temperatures.
Innovation Solution
A multi-layered structure is created by surface treating the substrate to increase its energy, applying a water-based tie-layer and ink-receptive layer comprising multivalent metal salts and hydrophilic binders, and using anionically stabilized water-based pigment inks, which are printed in a single pass with inkjet systems, followed by additional layers for protection and adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If water-based inkjet inks are deposited on water-impermeable substrates, then the ink drops tend to bead up or flow across the surface, but this results in image quality artifacts such as mottle, coalescence, and intercolor bleeding
Solution Approach 1:
The patent introduces an intermediary layer between the water-based ink and the water-impermeable substrate to facilitate proper ink adhesion and prevent beading or flowing. This intermediate layer acts as a bridge that allows the ink to properly wet and adhere to the substrate surface without direct contact, thereby eliminating image quality artifacts while maintaining the simplicity of the deposition process.
2Strength
If water-based inks with high co-solvent content (>10-15 wt%) are used to improve wetting, then adhesion improves, but the inks become very difficult to completely dry resulting in sticky or tacky ink layers
Solution Approach 1:
The patent modifies the chemical composition parameters of the water-based ink by adjusting the type and concentration of surfactants and co-solvents. This parameter optimization allows the ink to achieve adequate wetting and adhesion to water-impermeable substrates while maintaining a co-solvent content that enables complete drying, thereby eliminating the sticky or tacky residue problem associated with high co-solvent formulations.
3Strength
If substrate heating is applied to melt and fuse polymer particles for direct printing, then ink adhesion improves, but many water-impermeable plastic substrates are prone to wrinkling or melting at temperatures as low as 50°C
Solution Approach 1:
The patent employs an intermediary layer that enables ink adhesion to water-impermeable substrates without requiring high-temperature heating. This intermediate layer provides a surface that the ink can bond to at lower temperatures, thereby achieving strong adhesion while preventing substrate wrinkling or melting that would occur with direct high-temperature heating of temperature-sensitive plastic substrates.
4Manufacturing precision
If high ink coverage is deposited to achieve complete color coverage, then print quality improves, but bleeding between colors or image non-uniformity (mottling) occurs
Solution Approach 1:
The patent uses an intermediary layer that controls ink spread and prevents color bleeding while allowing complete color coverage. This intermediate layer acts as a barrier that confines the ink within the intended print areas, enabling high ink coverage for complete color saturation without the intercolor bleeding or mottling that would otherwise occur at high coverage levels.
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
This method produces high-quality, durable printed images with improved adhesion and cohesion, suitable for high-speed production on water-impermeable substrates without requiring radiation curable components, maintaining substrate integrity and enhancing print durability.
Implementation Method 1
a water-based ink-receptive layer comprising a multivalent metal salt and a hydrophilic binder
Implementation Method 2
a water-based ink-receptive layer comprising a multivalent metal salt and a hydrophilic binder
Implementation Method 3
the ink-receptive layer is capable of absorbing a water-based inkjet ink
Implementation Method 4
improved adhesion and cohesion
Data Source
Figure 1~2
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AI summary
In accordance with the present invention, there is provided a multilayered structure includes: a) a water-impermeable substrate (100); b) a first layer (301) on at least one surface of the substrate comprising a water-based tie-layer composition; c) a second layer (401) formed over the first layer, wherein the second layer is a water-based ink-receptive composition includes: i) a multivalent metal salt; and ii) a hydrophilic binder polymer; d) a third layer (501) including at least one water-based ink composition deposited in a single pass by an inkjet printing process, wherein the water-based ink composition includes an anionically stabilized, water-dispersible pigment; and e) additional layers (901) deposited over the one or more ink layers and exposed second layer, the additional layers selected from one or more of the following compositions: i) an opaque white layer; ii) a protective layer; and iii) an adhesive layer, further includes a continuous protective plastic or paper layer adhered thereto.