Embedded Security Element Bonding for Card Lamination
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Solution Overview
Problem
Existing methods fail to securely attach security elements with relief structures to cards without damaging them during the lamination process, leading to compromised visual recognizability and bond strength, while also being vulnerable to mechanical wear and removal.
Innovation Solution
A multi-layer card structure with a security element embedded between transparent cover layers, using a stabilizing adhesive that ensures the security element's visibility and detectability, even under gentle lamination conditions, and provides a strong bond without damaging the sensitive structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If security elements with relief structures are glued onto the outer surface of the card, then the security element can be permanently fixed, but the relief structures become affected by abrasion and mechanical stresses leading to loss of optical effects
Solution Approach 1:
The security element is embedded within the card structure by placing it between two card layers, similar to nesting one object inside another. This embedding protects the relief structures from external mechanical stresses and abrasion while maintaining permanent fixation through the lamination process.
2Reliability
If security elements are embedded between card layers, then the security element is protected from mechanical wear, but the relief structures are exposed to heat and pressure during lamination causing severe quality degradation
Solution Approach 1:
The lamination process applies different conditions to different areas: gentle lamination with reduced heat and pressure is applied specifically to the security element area to preserve relief structure quality, while standard lamination conditions are used in other areas of the card to ensure proper bonding.
Solution Approach 2:
The lamination parameters (temperature and pressure) are changed locally in the security element area during the lamination process. Reduced temperature and pressure are applied to this specific region to prevent damage to the relief structures while maintaining adequate bonding.
3Manufacturing precision
If gentler treatment is applied to security element areas during lamination, then the quality of relief structures is slightly improved, but the film composite becomes poorer leading to reduced visual recognizability and delamination
Solution Approach 1:
Different lamination conditions are applied to different regions: the security element area receives gentle treatment to preserve relief structure quality, while surrounding areas receive standard treatment to ensure strong film composite and prevent delamination.
Solution Approach 2:
A transparent cover layer is introduced as an intermediary between the security element and the external environment. This cover layer protects the relief structures from mechanical damage while allowing optical effects to pass through, and it is bonded using standard lamination conditions to ensure strong film composite.
4Stability of the object's composition
If standard lamination conditions are applied to cards with embedded security elements, then good film composite is achieved, but the relief structures are damaged leading to loss of security features
Solution Approach 1:
The lamination process is differentiated by region: gentle lamination with reduced heat and pressure is applied specifically to the security element area to preserve relief structure quality, while standard lamination conditions are applied to other areas to ensure good film composite.
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 solution enhances the visual recognizability and detectability of security features, particularly the hidden image information, while maintaining a high bond strength and protecting against counterfeiting and mechanical wear.
Implementation Method 1
using a stabilizing adhesive that ensures the security element's visibility and detectability
Implementation Method 2
the optical effects caused by the diffraction structures or refraction structures
Implementation Method 3
transparent card cover layers...enhances the visual recognizability and detectability of security features
Data Source
Figure 1~2c
Figure 3~5
Figure 6~9
AI summary
The invention relates to a card (1), such as a credit card or identification card, comprising a plurality of layers that are laminated to each other, wherein between a first card layer (21) and a second card layer (22) a security element (2) is embedded, having a plastic or paint layer (4) with a relief structure (5). The relief structure comprises regions (51, 5") having different image elements and produces a visible image (6) and a hidden image (7) which can be made visible with auxiliary means. The security element is glued to the two card layers (21, 22), between which it is embedded, by adhesive layers (9, 10), wherein the adhesives are selected from the group consisting of physically drying adhesives and adhesives that can be crosslinked by heat, preferable water-based adhesives. When an adhesive that can be crosslinked by heat is used, the crosslinking temperature of the adhesive is lower than the softening temperature of the plastic or paint layer (4) in which the relief structure (5) is present. The invention further relates to a method for producing a card of said kind.