Security Paper UV Lacquer for Dirt Repellency
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Solution Overview
Problem
Optically variable anti-counterfeiting means on documents, such as security papers, face issues with dirt repellency without impairing their optical effects, leading to unsightly stains around recessed areas.
Innovation Solution
A security paper with a radiation-curing, high-gloss UV lacquer applied around optically variable security features to enhance dirt repellency without affecting their appearance, combined with a water-based primer layer and a physically drying or UV-crosslinking second lacquer for additional protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a protective lacquer layer is applied around optically variable security features, then dirt repellency is improved, but the optical clarity and visual appearance may be impaired
Solution Approach 1:
The patent applies a protective lacquer layer with specific properties (high-gloss, UV-curing) in the area surrounding the optically variable security features, while deliberately excluding the lacquer from the security features themselves. This localized application ensures dirt protection where needed while preserving the optical clarity and visual appearance of the security features.
Solution Approach 2:
The patent specifies precise parameters for the protective lacquer layer, including a thickness range of 0.7 to 2 μm (preferably 0.7 to 1.5 μm) and high-gloss finish. These parameter controls ensure the lacquer provides adequate dirt repellency while remaining thin enough not to significantly impact the optical properties of the underlying security features.
2Duration of action of stationary object
If a protective lacquer layer is applied to extend service life, then durability is improved, but the complexity of the production process increases
Solution Approach 1:
The protective lacquer layer is applied as part of the paper production process itself, rather than as a separate post-processing step. The lacquer is applied to the substrate before the optically variable security features are added, allowing the protective layer to be integrated into the base paper structure and simplifying the overall production workflow.
Solution Approach 2:
The patent employs UV-curing technology to rapidly harden the protective lacquer layer after application. This photopolymerization process replaces traditional lengthy drying or curing methods, significantly reducing processing time and simplifying the production workflow while ensuring complete hardening for maximum durability.
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 significantly improves dirt resistance around anti-counterfeiting agents while maintaining their optical clarity and visual appeal, extending the service life and fitness for circulation of security documents.
Implementation Method 1
a radiation-curing, high-gloss UV lacquer
Implementation Method 2
optically diffractive optical markings (hologram)
Data Source
Figure 1~2a
Figure 2b~2c
AI summary
The invention relates to a security paper for producing documents of value, comprising a planar substrate that is equipped on one surface with a counterfeit-protection means based on a carrier film that comprises an optically-variable security feature, this counterfeit-protection means and a substrate subsurface which surrounds said means being provided with a radiation-curing, dirt-repellent first coating for the purpose of prolonging the life-span and fitness for circulation, this first coating having substantially no effect on the noticeability of the optically-variable security feature and having a layer thickness lying in a range between 0.7 and 2 micrometres. The radiation-curing first coating is preferably a UV-crosslinking coating which is high-gloss once it has been cross-linked, i.e. it has only a very low degree of scattering and thus only a very low degree of matting. On the surface of the substrate that lies outside the counterfeit-protection means, said substrate may be provided with a dirt-repellent second coating which, where appropriate, partially overlaps said first coating in the region of the substrate subsurface that surrounds said counterfeit-protection means. The second coating is based either on a physically-drying water-based dispersion coating or on a UV-crosslinking coating, and displays a matt effect.