Flexible Packaging Lamination with Immediate Bonding
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Solution Overview
Problem
Conventional laminating technologies for flexible packaging materials require prolonged curing times, which negate the advantages of short turnaround in digital printing processes, leading to delays in packaging food products.
Innovation Solution
A process involving a liquid electrophotographic printing composition with a polymer resin and thermally activatable laminating layer that allows for immediate lamination and bonding without cure time, enabling in-line integration with electrostatic printing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional laminating technologies are used, then lamination bond strength is achieved, but prolonged curing times are required which delay production
Solution Approach 1:
The patent changes the chemical parameters of the lamination system by using a pressure-sensitive adhesive composition with specific functional groups (carboxylic acid, hydroxyl, or amine groups) that can chemically interact with the electrophotographic toner particles. This chemical interaction enables immediate bonding without prolonged curing times, resolving the contradiction between bond strength and curing time
Solution Approach 2:
The invention creates a composite laminating structure consisting of multiple layers including a pressure-sensitive adhesive layer, a barrier layer, and optionally a release liner. The adhesive layer contains specific polymers (polyacrylic acid, polyvinyl alcohol, polyethyleneimine) that form chemical bonds with toner particles, while the barrier layer provides additional protection. This composite structure achieves strong bonding immediately upon lamination without requiring extended curing
2Productivity
If digital printing processes are used, then short turnaround time is achieved, but conventional lamination curing times negate this advantage
Solution Approach 1:
The patent incorporates the adhesive functionality directly into the lamination layer itself, eliminating the need for separate curing steps. The pressure-sensitive adhesive composition is designed to bond immediately with electrophotographic toner upon contact, allowing the lamination process to occur immediately after printing without waiting for curing. This preliminary preparation of the adhesive system enables continuous in-line processing
Solution Approach 2:
The invention merges the adhesive function with the lamination function into a single integrated layer. The pressure-sensitive adhesive layer serves both as the bonding agent and as part of the final laminated structure, eliminating the need for separate adhesive application and curing steps. This integration allows digital printing and lamination to be combined in a continuous in-line process, maintaining short turnaround times
3Productivity
If immediate lamination is achieved, then production efficiency is improved, but strong and reliable bond strength must be maintained
Solution Approach 1:
The patent modifies the chemical composition parameters of the adhesive layer by incorporating polymers with specific functional groups (carboxylic acid, hydroxyl, or amine groups) that form strong chemical bonds with electrophotographic toner particles. The adhesive composition includes polymers such as polyacrylic acid, polyvinyl alcohol, or polyethyleneimine with controlled molecular weights and functional group densities. These parameter changes enable immediate bonding with reliable strength, matching or exceeding conventional cured adhesives
Solution Approach 2:
The invention applies different functional properties to different regions of the laminating structure. The pressure-sensitive adhesive layer contains specific polymers and functional groups optimized for chemical bonding with toner particles, while the barrier layer provides protection and structural integrity. This local differentiation of material properties ensures that bonding occurs immediately with high reliability at the toner-adhesive interface, while the overall structure maintains durability
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 process achieves immediate and strong lamination bond strength, eliminating the need for post-printing wait times and streamlining the production of flexible packaging materials, making them ready for use upon cooling to room temperature.
Implementation Method 1
applying an ink having charged particles to the photoconductive surface, such that they selectively bind to the image
Implementation Method 2
thermally activatable laminating layer that allows for immediate lamination and bonding without cure time
Data Source
Figure 1a~1
AI summary
Flexible packaging materials with electrophotographically printed images or information, and processes for preparing such flexible packaging materials are disclosed.