Multilayer Film Structure for Rapid Lamination
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Solution Overview
Problem
The complexity of incorporating multiple security features into security documents, such as identification cards and passports, while ensuring rapid and cost-efficient production, is hindered by the need for suitable material combinations that maintain adhesion and transparency, particularly in the presence of heat-sensitive layers.
Innovation Solution
A multilayer construction with outer layers having a Vicat softening temperature of ≥149°C and inner layers with lower softening temperatures, including a core layer with optional heat protection, allows for the incorporation of various security features like holograms and transparent regions while ensuring adhesion and efficient production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple security features are incorporated into security documents, then security level is improved, but production complexity increases
Solution Approach 1:
The security document is divided into multiple functional layers including outer layers with high Vicat softening temperature polymers, intermediate polymer layers, and a core layer. Each layer serves specific functions such as protection, adhesion, and heat sensitivity control, allowing complex security features to be implemented in a structured manner that simplifies production
Solution Approach 2:
The patent employs composite material structures where outer layers contain polymers with Vicat softening temperature ≥149°C (such as polycarbonates), while intermediate and core layers use polymers with lower softening temperatures. This composite approach enables both high security feature incorporation capability and controlled production processes by matching material properties to functional requirements
2Temperature
If outer layers use polymer with high Vicat softening temperature (≥149°C), then heat resistance and adhesion are improved, but production time increases due to higher processing temperatures
Solution Approach 1:
The layer structure is segmented into outer layers with high heat resistance (Vicat ≥149°C) and inner layers with lower heat resistance. This segmentation allows the outer layers to provide necessary adhesion and protection at high temperatures while inner layers with lower melting points can be processed more rapidly, enabling overall production speed improvement without sacrificing heat resistance where needed
Solution Approach 2:
Different regions of the multilayer construction have different thermal properties tailored to local functional requirements. Outer layers have high Vicat softening temperature for adhesion and protection, while core and intermediate layers have lower temperatures for rapid processing. This local optimization resolves the contradiction between heat resistance and production speed
3Illumination intensity
If transparent regions (windows) are created in security documents, then transparency and visual security features are improved, but vulnerability to counterfeiting increases
Solution Approach 1:
The transparent window regions are created as composite structures involving multiple layers including outer layers with high Vicat softening temperature polymers, intermediate polymer layers, and core layers. This composite construction maintains transparency for visual security features while the multi-layer structure with different thermal properties prevents easy counterfeiting by requiring complex reproduction of the layered architecture and heat-sensitive security elements
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 solution enables the creation of secure documents with enhanced security features, improved transparency, and durability, while facilitating rapid and cost-effective production by maintaining layer adhesion and clarity, even under heat stress.
Implementation Method 1
the outer layers (S1) and (S5) independently of one another contain a polymer (P1) that has a Vicat softening temperature of ≥149° C.
Implementation Method 2
ensuring through the choice of the materials that the adhesion of the layers to one another is sufficient for them not to readily become detached from each other
Implementation Method 3
The polymer layers (S1), (S2), (S4) and (S5) and optionally also (S6) preferably have a light transmittance in the visible range of within a range from ≥85% to ≤98%
Data Source
AI summary
The invention relates to a multi-layer structure (MA) comprising: (S1) at least one first outer layer (S1) containing a polymer (P1) having a Vicat softening temperature ≥149° C., preferably ≥160° C., further preferably ≥170° C., more preferably ≥180° C., determined according to ISO 306:2004 (50N; 50° h); (S2) at least one further polymer layer (S2) containing a polymer (P2) having a Vicat softening temperature <149° C., preferably ≤140° C., more preferably ≤130° C. determined according to ISO 306:2004 (50N; 50°/h), preferably in a range from 120 to 148° C.; (S3) at least one core layer (S3); (S4) at least one further polymer layer (S4) containing a polymer (P2) having a Vicat softening temperature <149° C., preferably ≤140° C., more preferably ≤130° C., determined according to ISO 306:2004 (50N; 50° h), preferably in a range of 120 to 148° C.; (S5) at least one second outer layer (S5) containing a polymer (P1) having a Vicat softening temperature ≥149° C., preferably ≥160° C., further preferably ≥170° C., more preferably ≥180° C., determined according to ISO 306:2004 (50N; 50°/h). The invention also relates to a method for manufacturing such a multi-layer structure and to a security document containing same.