Pre-coating Composition for Ink-jet Printed Packaging Laminate Adhesion
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Solution Overview
Problem
Conventional ink-jet printing technologies face challenges in achieving good adhesion between the printed décor layer and the outermost thermoplastic polymer layer in laminated packaging materials, leading to issues like delamination, ink retransfer, and compromised package integrity, especially in high-speed printing processes.
Innovation Solution
A pre-coating composition comprising an aqueous soluble multivalent cation salt, such as calcium chloride, and a hydrophilic polymer binder is applied to the substrate surface to enhance adhesion between the ink-jet printed décor layer and the thermoplastic polymer layer, improving image quality and package integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional ink-jet printing is used on the substrate surface, then printing speed and productivity are improved, but adhesion between the printed décor layer and the thermoplastic polymer layer deteriorates
Solution Approach 1:
The patent introduces a pre-coating layer as an intermediary between the substrate surface and the ink-jet printed décor layer. This pre-coating comprises a polymeric binder and a multivalent cation salt, which together create an optimized surface that enhances ink adhesion and subsequently improves the bonding between the printed décor layer and the thermoplastic polymer layer, resolving the adhesion problem while maintaining high-speed printing capability
Solution Approach 2:
The patent modifies the surface properties of the substrate by applying a pre-coating with specific compositional parameters (polymeric binder with multivalent cation salt at controlled ratios). This changes the surface energy, porosity, and chemical composition to optimize both ink absorption during high-speed printing and subsequent adhesion to the thermoplastic layer, thereby resolving the contradiction between printing speed and adhesion quality
2Productivity
If high-speed ink-jet printing is used, then manufacturing efficiency is improved, but image quality and package integrity deteriorate due to delamination and ink retransfer
Solution Approach 1:
The pre-coating layer serves as a mediator that stabilizes the printed décor layer during high-speed printing and subsequent lamination processes. It prevents ink retransfer by providing a controlled absorption surface and prevents delamination by enhancing the bonding interface between the décor layer and thermoplastic polymer layer, thereby maintaining image quality and package integrity while enabling high-speed manufacturing
Solution Approach 2:
The pre-coating is applied in advance before the ink-jet printing process. This preliminary action prepares the substrate surface with optimal properties for both ink absorption and subsequent adhesion, ensuring that even during high-speed printing, the image quality is maintained and the printed layer will adhere properly to the thermoplastic polymer layer, preventing delamination
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 pre-coating composition ensures strong adhesion between the printed décor layer and the outermost thermoplastic polymer layer, maintaining image quality and package integrity, while reducing issues like delamination and ink retransfer, thereby enhancing the durability and barrier properties of the packaging material.
Implementation Method 1
a pre-coating for receiving a printed décor of an aqueous, pigment-based, ink-jet printing ink
Implementation Method 2
a polymer binder, being a hydrophilic polymer, at a weight ratio of from 1:10 to 2:5, calculated on solid matter
Data Source
Figure 1a~1b
Figure 2
Figure 3
AI summary
The invention relates to a laminated packaging material for food packaging, comprising a core layer of paper or paperboard, which on a first side intended to be directed towards the outside of a packaging container, has, in the following order, a dry pre-coating for receiving a printed decor of an aqueous, pigment-based, ink-jet printing ink, a pigment-based ink-jet printed ink decor layer and further laminated onto the printed decor layer, a protective outermost layer of a thermoplastic polymer. The invention also relates to a method for manufacturing of the packaging laminate and to a packaging container that is made from the laminated packaging material as well as to a pre-coating composition for use in the laminated packaging material and in the manufacturing thereof.