UV-Cured Inkjet Adhesive for Foiling Applications
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Solution Overview
Problem
Current cold foiling and hot foiling techniques face challenges such as adhesive viscosity issues, tackiness problems, and inefficiencies in foil transfer, leading to subpar image formation and increased foil waste due to incomplete curing and handling complexities.
Innovation Solution
A novel adhesive composition that cures to a tack-free, hardened state upon exposure to UV, LED, or electron-beam radiation, and subsequently becomes tacky under heat and pressure, enabling efficient and precise die-less foil transfer using inkjet printheads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If UV curing dosage is reduced to manipulate adhesive viscosity and initiate tackiness, then adhesive viscosity and surface tackiness are improved, but adhesive hardness and image formation quality deteriorate
Solution Approach 1:
The adhesive is fully cured to a hardened, tack-free state before foil application, establishing a stable base layer. Heat is then applied at the moment of foil contact to temporarily reactivate tackiness only where needed, rather than maintaining partial cure throughout the process
Solution Approach 2:
The adhesive's physical state is controlled by changing temperature parameter: fully cured at room temperature, then temporarily softened by heat application during foil transfer, returning to hardened state after cooling
2Ease of operation
If adhesive is partially cured to maintain tackiness for foil transfer, then foil transfer capability is improved, but adhesive stability and resistance to spread deteriorate
Solution Approach 1:
The adhesive is pre-applied and fully cured to a stable, tack-free state, then heat is applied only when foil transfer is required, temporarily creating tackiness at the moment of need while maintaining stability during storage and handling
Solution Approach 2:
The adhesive undergoes reversible phase transition between hardened state (stable) and softened tacky state (operationally active) through temperature control, allowing stable storage followed by controlled activation during foil transfer
3Stability of the object's composition
If adhesive is fully cured and hardened before foil application, then adhesive stability and image formation are improved, but foil transfer capability deteriorates
Solution Approach 1:
Temperature parameter is changed from room temperature (maintaining hardened state) to elevated temperature (activating tackiness), enabling the adhesive to switch between stable and operationally active states as needed
Solution Approach 2:
The adhesive cycles between two states: hardened and stable during storage/transport, then temporarily softened and tacky during foil transfer, returning to hardened state afterward. This periodic activation through heat application solves the contradiction between stability and operability
4Productivity
If inkjet adhesive viscosity is reduced for proper jetting, then jetting performance is improved, but adhesive tackiness and viscosity for foil transfer deteriorate
Solution Approach 1:
The adhesive viscosity is controlled through chemical composition for proper jetting, then physical state is changed through UV curing to hardened tack-free, and finally temporary viscosity reduction is achieved through heat application during foil transfer
Solution Approach 2:
The adhesive is formulated with appropriate viscosity for inkjet application, then fully cured to establish a stable hardened layer, and only when needed is heat applied to temporarily reduce viscosity and create tackiness for foil transfer
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 adhesive composition allows for convenient, efficient, and reliable foil transfer with improved image quality and reduced foil waste by ensuring full curing before transfer, while maintaining flexibility and adhesion properties.
Implementation Method 1
Upon exposure to one of UV, LED, or electronic beam radiation, the adhesive is fully hardened
Implementation Method 2
The hardened adhesive surface will become tacky upon exposure to heat and pressure
Data Source
AI summary
Adhesive compositions that can be applied to substrates using inkjet printheads and cured to a hardened, tack-free state and readily rendered tacky on application of heat and pressure to accurately transfer foil to the substrates including one or more free-radical curing monomers, an oligomer/resin composition component including one or more oligomers and one or more inert thermoplastic resins that are soluble in the monomers, and, where required, one or more free radical photoinitiators.