Security Element Film Coating Counterforce Bulging

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Solution Overview

Problem

Existing security elements for documents of value face challenges in maintaining flatness and stability due to expansion differences caused by temperature and humidity changes, especially when substrates with openings are sealed with films having different expansion capacities, leading to bulging issues during stacking or processing.

Innovation Solution

A security element is created by applying a non-self-supporting coating to one side of a substrate with an opening, and then sealing it with a partially translucent or transparent film on the opposite side, ensuring the coating is not within the opening, which builds a counterforce to the film and maintains flatness and stability during processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a substrate with an opening is sealed with a film on one side, then the opening is closed and protection is provided, but the substrate bulges due to expansion differences between the film and substrate under temperature and humidity changes

Engineering Contradiction:
Improveprotection against forgeryVSAvoidflatness of substrate
Core Design Contradiction:
ReliabilityVSShape

Solution Approach 1:

The patent applies a coating to only one side of the substrate (the side opposite the film), creating an asymmetric structure. This asymmetric coating distribution provides counterforce specifically where needed to counteract the bulging caused by the film-substrate expansion differential, while maintaining the protective sealing function of the film over the opening.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent modifies the physical parameters of the substrate system by introducing a coating with specific expansion characteristics. This coating changes the overall expansion behavior of the substrate-film assembly, allowing it to better accommodate temperature and humidity changes without bulging, thus resolving the contradiction between protection and flatness.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If a film is applied to close the opening on one side of the substrate, then sealing is achieved, but the flatness of the substrate is significantly influenced and bulging occurs

Engineering Contradiction:
Improvesealing of openingVSAvoidflatness of substrate
Core Design Contradiction:
Stability of the object's compositionVSShape

Solution Approach 1:

The asymmetric application of coating to only one side of the substrate creates a balanced force distribution. The coating on the film-opposite side provides counterforce that compensates for the stresses introduced by the film sealing, preventing bulging while maintaining the seal integrity.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The coating is applied locally to specific areas of the substrate, particularly in regions where bulging would occur. This localized quality enhancement provides targeted support and counterforce exactly where the film-substrate expansion differential creates stress, rather than uniformly treating the entire substrate surface.

Inventive Principle:
Principle #3Local quality

3Reliability

If the substrate expansion capacity differs greatly from the film expansion capacity, then sealing is achieved, but changes in humidity and temperature greatly impair the flatness of the substrate

Engineering Contradiction:
Improvesealing effectivenessVSAvoidflatness under environmental changes
Core Design Contradiction:
ReliabilityVSShape

Solution Approach 1:

The patent introduces a coating with specific expansion parameters that bridge the gap between substrate and film expansion characteristics. This coating layer modifies the overall thermal and hygral expansion behavior of the assembly, allowing it to accommodate environmental changes without compromising flatness or seal integrity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite structure consisting of substrate, film, and coating layers with different expansion properties. This composite material system is designed to harmonize the expansion differences between components, distributing environmental stresses across multiple layers with complementary characteristics to maintain flatness under varying humidity and temperature conditions.

Inventive Principle:
Principle #40Composite materials

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 prevents bulging caused by moisture and temperature changes, ensures unrestricted overprintability, and provides increased stability during folding or bending by equalizing stress and tension, making the security element advantageous for documents of value.

Implementation Method 1

The expansion capacity of the substrate, which consists of paper and/or a plastic film, depends on the parameters of temperature, humidity and the orientation of the fiber strands and polymer strands of the paper or film. If a substrate provided with a continuous opening is closed on one side with a film whose expansion capacity differs greatly from that of the substrate, changes in humidity and/or temperature can greatly impair the flatness of the substrate.

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

The expansion capacity of the substrate, which consists of paper and/or a plastic film, depends on the parameters of temperature, humidity and the orientation of the fiber strands and polymer strands of the paper or film.

Methodology Applied
Scientific EffectHygroexpansion: Thermal Expansion

Data Source

PatentEP2461970B2Method for producing a security element and security element obtainable according to the method
Publication Date: 2022.10.05 GIESECKE & DEVRIENT CURRENCY TECHNOLOGY GMBH
  • EP2461970B2 patent drawingFigure 1~2c
  • EP2461970B2 patent drawingFigure 3a~3c

AI summary

The invention relates to a security element (1) comprising a substrate (2) having at least one opening (3), wherein the opening (3) is closed on one side by an at least partially translucent or transparent film (4), and a coating is present on the side of the substrate (2) opposite the film (4) in the region of the opening (3) and substantially in the region of the film surface, and wherein the coating (5) is not present or is substantially not present within the opening (3).