Water-Impermeable Substrate Printing with Ink-Receptive Layer

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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 low temperatures.

Innovation Solution

A method involving surface treatments and pre- and post-print coatings on water-impermeable substrates using a water-based ink-receptive layer comprising multivalent metal salts and hydrophilic binders, along with a tie-layer for improved adhesion, allows for high-quality, high-speed printing with water-based inkjet inks containing less than 15 wt% organic co-solvents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If water-based inks are deposited on water-impermeable substrates, then environmental and health safety are improved, but wetting and adhesion are worsened

Engineering Contradiction:
Improveenvironmental and health safetyVSAvoidwetting and adhesion
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent introduces an ink-receptive layer as an intermediary between the water-impermeable substrate and the water-based ink. This layer comprises multivalent metal salts (such as aluminum, calcium, or zinc salts) and hydrophilic binders that create a surface capable of accepting and adhering water-based inks, thereby enabling the use of environmentally safe water-based inks on traditionally incompatible substrates.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If ink-receptive layer is applied to improve wetting, then adhesion is improved, but substrate complexity increases

Engineering Contradiction:
ImproveadhesionVSAvoidsubstrate structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The ink-receptive layer is applied in advance to the substrate before the actual printing process. This preliminary action prepares the substrate surface with multivalent metal salts and hydrophilic binders, creating a permanent or semi-permanent modification that simplifies subsequent printing operations by ensuring reliable ink adhesion without requiring complex real-time adjustments during printing.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If high speed printing is used to increase productivity, then output is improved, but image quality deteriorates

Engineering Contradiction:
Improveprinting speedVSAvoidimage quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The ink-receptive layer acts as a mediator that enables high-speed printing by providing a surface that rapidly accepts and secures water-based inks. The multivalent metal salts in the layer create strong binding sites that prevent ink spread and mottle even at high deposition speeds, allowing the printing system to operate at high productivity while maintaining sharp, clean image quality.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 approach enables the production of high-quality, durable multi-layered images on water-impermeable substrates with improved wetting, adhesion, and reduced mottle, while maintaining environmental and health safety standards, particularly suitable for flexible film food packaging and labels.

Implementation Method 1

A method of printing water-based inks on water-impermeable, low-surface-energy substrates

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

a water-based ink-receptive layer comprising multivalent metal salts and hydrophilic binders

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentEP3328659B1Printing on water-impermeable substrates with water-based inks
Publication Date: 2020.02.19 EASTMAN KODAK CO
  • EP3328659B1 patent drawingFigure 1~2
  • EP3328659B1 patent drawingFigure 3
  • EP3328659B1 patent drawingFigure 4

AI summary

A method of printing with water-based inkjet inks on a water- impermeable, low-surface-energy substrate, includes: a) modifying surface properties of the substrate to increase the surface energy; b) coating the modified surface of the substrate with a first layer comprising a colorless water-based tie-layer composition; c) coating over the first layer with a second layer including a colorless and transparent water-based ink-receptive composition including: i) a water-soluble multivalent metal salt; and ii) a hydrophilic binder polymer; d) depositing directly on the surface of the second layer one or more water-based ink compositions containing an anionically stabilized pigment colorant, wherein the one or more water-based ink compositions are deposited in a predetermined pattem with an inkjet deposition system in response to electrical signals; and e) drying the first and second coated layers and the deposited inks to substantially remove the water.