Composite Banknote Substrate with Embedded Security Thread
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Solution Overview
Problem
Current methods for producing banknotes and other documents of value struggle to enhance security against forgery while maintaining mechanical durability and resistance to soiling, as coatings do not significantly improve mechanical properties and reinforcing fibers increase soiling due to higher porosity.
Innovation Solution
A multi-layer document substrate production method involving a first layer with a through opening, a second layer, and an elongate security element, where laminating adhesive is applied using kiss printing to prevent contamination, allowing the security element to be embedded between the layers without hot-seal adhesive, ensuring a secure and durable composite structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If coatings are applied to printed banknotes to reduce soiling, then resistance to soiling is improved, but mechanical properties are hardly improved
Solution Approach 1:
The patent uses a composite structure consisting of a paper substrate layer and a plastic film layer bonded together. The paper substrate provides typical banknote properties (sound, feel, printability) while the plastic film layer enhances durability, tear propagation resistance, and soiling resistance. This composite approach allows each material to contribute its strengths without compromising the other.
2Strength
If reinforcing fibers are added to improve mechanical resistance, then strength is improved, but soiling increases due to higher porosity
Solution Approach 1:
Instead of adding reinforcing fibers to paper (which increases porosity and soiling), the patent bonds a plastic film layer to the paper substrate. This film layer provides the needed mechanical strength and tear resistance without creating additional porosity, thereby avoiding increased soiling while maintaining mechanical properties.
3Ease of manufacture
If laminating adhesive is applied to a layer with through openings using conventional methods, then lamination is achieved, but the laminating system becomes contaminated
Solution Approach 1:
The patent extracts the adhesive application step from direct contact with the perforated layer by applying adhesive to the non-perforated plastic film layer instead. This eliminates the source of contamination (adhesive passing through openings) while still achieving proper lamination of all layers including the perforated security element.
Solution Approach 2:
The patent uses the non-perforated plastic film layer as an intermediary surface for adhesive application. The adhesive is applied to this intermediate layer rather than directly to the perforated layer, preventing contamination of the laminating system while ensuring the adhesive still bonds all layers together effectively.
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
This method enhances security against forgery by embedding the security element within the substrate layers, maintaining mechanical durability and resistance to soiling, and allowing for a single-stage lamination process without contaminating the laminating system, resulting in a more secure and durable document.
Implementation Method 1
applying laminating adhesive onto a surface of at least the first layer by means of kiss printing... laminating the first layer, the second layer and the elongate security element together using laminating rollers
Data Source
Figure 1~3
Figure 4~5
Figure 6~7b
AI summary
The invention relates to a method for producing a multi-layered substrate (1a, 1b, 1c, 1d, 1f, 1g) for a valuable document, comprising . A) the provision of a first layer (2), a second layer (3), and an elongate security element (4) such as a security strip or security thread, said first layer (2) having at least one through-opening (5) and the first layer (2) and the second layer (3) each being selected to be a polymer layer or a paper layer, . B) the application of laminating adhesive (6) to a surface of at least the first layer (2), using the Kiss Print technique, . C) the lamination of the first layer (2), the second layer (3) and the elongate security element (4) together using laminating rollers such that the elongate security element (4) is embedded between the first layer (2) and the second layer (3) and the opening (5) of the first layer (2) is closed on one side by said elongate security element (4).