Composite Banknote Edge Splitting Prevention
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Solution Overview
Problem
Existing composite foil banknotes are prone to splitting when handled or subjected to manipulation, such as exposure to solvents or water, which can lead to counterfeiting, and previous solutions either compromise design freedom or require additional coatings that affect mechanical properties.
Innovation Solution
A composite foil banknote design featuring two polymeric cover layers directly connected at corners and edges with an intermediate layer that extends to the edges, reducing the risk of splitting and allowing for efficient production in a roll-to-roll process without the need for through-holes, while maintaining paper-like properties and security features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesive layers are used to connect paper core and film layers, then the layers are firmly held together, but the banknotes may still split at interfaces when handled or subjected to manipulation
Solution Approach 1:
The patent removes the adhesive layer from the system by directly fusing the paper core and film layers through heat and pressure. This eliminates the adhesive interface that becomes a weak point for splitting, while still achieving strong bonding between layers through direct thermal fusion.
Solution Approach 2:
The patent changes the bonding mechanism from chemical adhesion to thermal fusion by controlling temperature and pressure parameters during lamination. The film layers are heated above their melting point and pressed against the paper core, creating a direct molecular-level bond that resists splitting better than adhesive bonds.
2Strength
If through-holes are provided in paper core for adhesive flow, then outer layers can be connected directly, but design freedom is restricted
Solution Approach 1:
The patent eliminates through-holes from the paper core design. Instead of creating holes for adhesive flow, the entire surface of the paper core is used for direct thermal fusion with the film layers, preserving full design freedom while achieving strong edge connections.
Solution Approach 2:
The bonding process is segmented into controlled zones of heat and pressure application during lamination, allowing different areas of the banknote to receive appropriate bonding conditions without requiring physical holes through the paper core.
3Reliability
If peripheral edges are sealed after banknotes are singled, then edge delamination is protected, but roll-to-roll production is prevented
Solution Approach 1:
The patent performs the bonding action in advance during the lamination process itself, where film layers are thermally fused to the paper core before the banknotes are cut from the continuous roll. This preliminary bonding ensures edge delamination resistance is built into the structure, enabling efficient roll-to-roll production without subsequent edge sealing steps.
Solution Approach 2:
The patent combines the bonding function and edge protection function into a single lamination process. The thermal fusion that bonds layers together also simultaneously protects edges from delamination, eliminating the need for separate edge sealing operations and enabling continuous roll-to-roll production.
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 direct connection of cover layers at corners and edges significantly reduces the risk of splitting, both during normal use and attempted manipulation, while enabling efficient production and retaining design freedom, ensuring the banknote's integrity and security.
Implementation Method 1
The cover layers are directly connected to one another at least at the corners, but preferably also at least in sections at the edges
Implementation Method 2
a composite foil bank note (1) comprising two polymeric cover layers (12, 13) and at least one intermediate layer (11) lying between the cover layers
Data Source
Figure 1~3
Figure 4~6
Figure 7~8
AI summary
To prevent a foil-laminated banknote (1) from splitting, it is provided that the two cover layers (12, 13) are directly connected to each other, at least in the area of the corners (4), by welding, gluing, or crimping the cover layers (12, 13) together through a paper interlayer (11), or by leaving the interlayer (11) open in the area of the corners (2), so that the two cover layers (12, 13) form a firm connection when glued, welded, or crimped. Corresponding connection points by crimping, gluing, or welding can also be provided along sections of the banknote edges.