Security Element Production Using Embossed Masking Layer
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Solution Overview
Problem
Existing methods for producing strip-shaped security elements for documents require complex processes and substrates with watermarks, limiting their applicability and increasing the number of steps involved in production.
Innovation Solution
A method involving the application of an embossing lacquer layer, an opaque metallic layer, and a laser-resistant wash color on a polymeric carrier, where the wash color acts as a mask for laser radiation to selectively remove or transparentize the metallic layer, reducing the complexity and number of steps, and ensuring adhesion issues are avoided.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a substrate with watermark is used for laser demetallization, then the watermark can act as a mask to selectively remove metallic layer, but the method is not applicable to substrates without watermark and requires complex substrate preparation
Solution Approach 1:
An embossing structure is incorporated into the embossing lacquer layer before applying the metallic layer. This preliminary structuring provides the necessary mask pattern without requiring a watermark in the substrate, enabling the method to work on substrates without watermarks while maintaining selective laser demetallization capability
Solution Approach 2:
The masking function is separated from the substrate and transferred to the embossing lacquer layer. The embossing structure in the lacquer layer serves as an independent masking element, decoupling the substrate requirements from the masking requirements and allowing use of simple substrates without watermarks
2Ease of manufacture
If wash color is applied below metallic coating in prior art, then washing process creates cleartext opening, but this causes adhesion problems on substrate
Solution Approach 1:
The wash color is repositioned from below the metallic layer to above it, changing the vertical arrangement of layers. This dimensional repositioning allows the wash color to serve as a protective mask during laser processing while maintaining good adhesion to the substrate, eliminating the adhesion problems caused by wash color beneath the metallic layer
Solution Approach 2:
The embossing lacquer layer with embossed structure serves as an intermediary between the substrate and the metallic layer. It provides both adhesion support and the masking function, allowing the metallic layer to be applied uniformly while the embossed structure guides selective removal without compromising substrate adhesion
3Manufacturing precision
If multiple process steps are used for security element production, then manufacturing precision can be achieved, but the number of process steps and overall complexity increase
Solution Approach 1:
The masking function and the embossing function are merged into a single embossing lacquer layer with embossed structure. This consolidation eliminates the need for separate masking layers and reduces the number of process steps while maintaining the precision required for selective laser demetallization
Solution Approach 2:
The embossing lacquer layer performs multiple functions: it adheres to the substrate, provides the embossed structure for masking, and supports the metallic layer application. This multi-functionality reduces overall process complexity while maintaining manufacturing precision through the integrated design
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 simplifies the production process, eliminates adhesion problems, and allows for the creation of security elements that can be applied to substrates without watermarks, with fewer work steps and improved translucency control, enhancing the security features of documents.
Implementation Method 1
Removing or transparentizing the metallic layer from the top surface of the embossing structure using a laser beam
Implementation Method 2
the wash color and the metallic layer at least partially overlap and wherein the outline of the wash color forms information recognizable to an observer... the metallic layer is not removed or transparentized at the points where it overlaps with the wash color
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a method for producing a strip-shaped security element for valuable documents such as banknotes, identity cards, or the like, wherein the security element consists of a polymeric carrier layer (1) with a front and a back. The method according to the invention comprises the following steps: applying an embossing varnish layer (2.1) to the front of the polymeric carrier layer (1); introducing an embossing structure into the embossing varnish layer (2.1); applying an opaque metallic layer (3.1) to the top of the embossing structure, wherein the metallic layer (3.1) at least partially covers the top of the embossing structure; applying a wash color (4.1) to the top of the metallic layer (3.1), wherein the wash color (4.1) and the metallic layer (3.1) overlap at least partially and wherein the outline of the wash color (4.1) is defined.1) forms information recognizable to an observer; removal or transparentizing of the metallic layer (3.1) from the top of the embossed structure by means of a laser beam, wherein the metallic layer (3.1) is not removed or transparentized at the points where it overlaps with the wash color (4.1); washing off the wash color (4.1) from the surface of the metallic layer (3.1) with a washing liquid.