Inkjet Pre-treatment Composition for Corrugated Packaging
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Solution Overview
Problem
Current pre-treatment compositions for inkjet printing on corrugated packaging and cardboards suffer from moderate image fixation, easy rubbing off, and inhomogeneous color density due to inadequate ink spreading, leading to suboptimal image quality.
Innovation Solution
A pre-treatment composition comprising resin particles stabilized by non-ionic groups, a wax, and a multivalent metal salt or cationic polymer, applied via an inkjet method to enhance ink adhesion and durability, using a combination of polyurethane resin dispersions, non-ionic dispersants, and specific wax types to improve image quality and resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pre-coat composition contains a polyvalent metal salt, a wax, a dispersing agent, a latex and water, then the pre-coat can be applied to corrugated linerboard, but the ability to fix colour pigments to the substrate is moderate leading to easy rubbing off the image
Solution Approach 1:
The patent uses a composite pre-coat composition combining polyurethane resin particles, cationic polymer, multivalent metal salt, and wax. This composite formulation creates synergistic effects where the cationic polymer and multivalent metal salt work together to strongly bind anionic pigment particles to the substrate, while the polyurethane resin and wax provide mechanical adhesion and rubbing resistance, resulting in superior image fixation compared to single-component systems
Solution Approach 2:
The patent optimizes specific parameters including the charge density of the cationic polymer, the concentration of multivalent metal salt (0.1-10 wt%), and the particle size distribution of polyurethane resin (0.01-10 μm). These parameter optimizations create optimal conditions for pigment binding and image durability, transforming the moderate performance of conventional formulations into superior fixation and rubbing resistance
2Reliability
If a treatment composition includes a fixing agent, a wax, and a latex with anionic groups, then the composition can be applied to packaging liner, but image quality suffers from mottling and bad ink spreading resulting in inhomogeneous colour density
Solution Approach 1:
Instead of using anionic groups in the latex as stated in the background, the patent inverts the approach by using cationic polymer with positive charges. This inversion eliminates the electrostatic repulsion between anionic pigment particles and the latex, allowing uniform ink spreading and homogeneous colour density while maintaining strong image fixation through the cationic-polymer-multivalent metal salt-pigment binding mechanism
Solution Approach 2:
The cationic polymer acts as an intermediary between the multivalent metal salt and the anionic pigment particles. It bridges the gap by coordinating with both the multivalent metal salt and the pigment surface, facilitating uniform distribution and binding while preventing mottling and ensuring homogeneous colour density across the printed image
3Extent of automation
If inkjet printing is used for pre-printing liners, then digital printing capability is improved, but conventional flexographic or offset printing is still used for applying pre-coat indicating transition period challenges
Solution Approach 1:
The patent develops a pre-coat composition that is universally applicable to both conventional flexographic/offset printing and digital inkjet printing processes. The formulation maintains compatibility with traditional printing methods while being optimized for inkjet printing, enabling the same composition to work across different printing technologies during the transition period and eliminating the need for separate formulations
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 significantly enhances ink spreading, fixing, and image sharpness, while providing improved water resistance and storage stability, resulting in high-quality, durable inkjet printed images on corrugated substrates.
Implementation Method 1
The resin particle is stabilized by a non-ionic group or a non-ionic or amphiphilic compound
Implementation Method 2
The pre-treatment composition comprises a resin particle which is dispersed in the aqueous medium of the composition... to enhance ink adhesion and durability
Implementation Method 3
the pre-treatment composition is capable of receiving ink and holding colorants in the ink to a greater degree than a substrate not treated with a pre-coat
Data Source
Figure 1
AI summary
A pre-treatment composition for inkjet printing, comprising water, a water-soluble multi-valent metallic salt, a wax, a non-ionic dispersant and a resin particle, the resin particle is stabilized by a non-ionic group or non-ionic or amphiphilic compound. A fluid set comprising the pre-treatment composition and an aqueous inkjet ink is suitable for printing liners for corrugated packaging, folding boards or a corrugated card boards.