Latent-Reactive Adhesive Bonding for Anti-Manipulation Security Elements
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Solution Overview
Problem
Current methods for producing security or valuable products with diffractive security elements bonded to paper substrates via adhesive layers are vulnerable to manipulation and counterfeiting, as existing adhesives can be easily detached or compromised by solvents, and alternatives like rhodamines pose environmental and health risks.
Innovation Solution
A method involving a combination of hot-melt adhesive and latent-reactive adhesive, where the latent-reactive adhesive is activated at a higher temperature than the hot-melt adhesive, creating a strong, inseparable chemical bond between the substrate and security element, preventing detachment and manipulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hot-melt adhesive is used to bond diffractive security elements to paper substrates, then the bonding process is simple and efficient, but the security elements can be easily detached by heating or solvent manipulation
Solution Approach 1:
The adhesive system is segmented into two distinct components: hot-melt adhesive for initial bonding and latent-reactive adhesive for permanent fixation. This segmentation allows each adhesive to perform its specific function - the hot-melt adhesive enables easy application and initial bonding, while the latent-reactive adhesive provides irreversible security against manipulation through chemical crosslinking that activates under specific conditions
Solution Approach 2:
The hot-melt adhesive is applied first to enable immediate bonding of the security element to the substrate. This preliminary bonding action secures the element in position during subsequent processing, after which the latent-reactive adhesive is applied to create the permanent chemical bond that prevents future manipulation
2Object-affected harmful factors
If rhodamine indicator is incorporated into the adhesive to detect manipulation, then solvent-based counterfeiting can be detected, but the adhesive becomes potentially carcinogenic, mutagenic and ecotoxic
Solution Approach 1:
The harmful rhodamine indicator is completely removed from the adhesive system. Instead of using toxic chemical indicators, the patent relies on the physical-chemical properties of the latent-reactive adhesive itself - specifically, its activation behavior under heat or solvent exposure and its irreversible crosslinking reaction - to provide both manipulation detection and prevention without any toxic additives
3Device complexity
If a single adhesive layer is used to bond security elements, then the structure is simple, but the bond can be compromised by solvents or heat
Solution Approach 1:
The adhesive system uses a composite of two different adhesive materials with complementary properties. The hot-melt adhesive provides initial tack and bonding, while the latent-reactive adhesive provides permanent chemical crosslinking. This composite approach creates a bonded structure that combines the advantages of both adhesives - ease of application with irreversible security - resulting in superior overall bond strength and manipulation resistance
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 approach ensures a secure attachment of the diffractive security element to the paper substrate, making manipulation and counterfeiting nearly impossible by causing cohesive destruction of the paper and security element, thus enhancing the security features of the product.
Implementation Method 1
the adhesive containing at least one powdered antiblocking agent as a component, wherein the anti-blocking agent can be activated by heat and/or radiation and/or mechanical action and, after activation, is capable of undergoing a chemical reaction with a component of the adhesive and/or with itself
Implementation Method 2
diffractive security elements such as holograms, kinegrams and alphagrams are used to increase protection against counterfeiting, which are bonded to a paper carrier substrate with a hot-melt adhesive
Data Source
Figure 1~2
AI summary
The invention relates to a method for producing a security or valuable product, particularly a security or valuable document, with a substrate and a diffractive security element that is directly connected to the substate by means of an adhesive layer. The invention also relates to a security or valuable product produced by said method. The invention comprises the following steps: (i) a hot-melt adhesive and a latent-reactive adhesive are applied to a) a region of the substrate provided for the security element and/or b) the security element, either the hot-melt adhesive and latent-reactive adhesive being applied as a mixture or the hot-melt adhesive and the latent-reactive adhesive being applied separately from each other in sections, where an application temperature Ta1 of the hot-melt adhesive is lower than an application temperature Ta2 of the latent-reactive adhesive, and Ta1 ≤ T1 ≤ Ta2 is valid for a temperature T1 during the application; (ii) the security element is placed on the substrate; and (iii) heating is carried out to a temperature T2, where T2 ≥ Ta2.