Strip Film Security Elements with Segmented Adhesive

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Solution Overview

Problem

The existing strip-shaped endless films with UV embossing varnish coatings face issues during the detachment process, leading to spangles formation due to brittleness, which disrupts subsequent printing processes by depositing debris on printing rollers and causing defects in printed images.

Innovation Solution

The strip-shaped endless film design incorporates a UV embossing lacquer layer with gaps, a primer layer, and a heat-sealing lacquer layer, where the primer layer has larger dimensions than the UV lacquer and the heat-sealing lacquer has larger dimensions than the primer, ensuring the UV lacquer is prevented from breaking and spangles are avoided by using a discontinuous separating layer to prevent the adhesive layers from bonding to the carrier film, allowing clean detachment and application to security paper.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If UV embossing varnish is used on the carrier film, then security features are enhanced, but the varnish becomes brittle during detachment causing spangles formation

Engineering Contradiction:
Improvesecurity feature integrityVSAvoidspangles formation
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The carrier film is divided into individual detachable elements with separation zones between them. This segmentation allows each security element to be cleanly detached without the UV varnish bridging across adjacent elements, preventing spangles formation while maintaining security feature integrity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A release agent is applied in the separation zones to act as an intermediary that prevents the UV embossing varnish from bonding to the carrier film in those areas. This allows clean detachment of the security elements without the varnish breaking and forming spangles.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If the carrier film is removed during application, then transfer of security elements is enabled, but UV varnish brittleness causes splinter formation that deposits on printing rollers

Engineering Contradiction:
Improvetransfer applicationVSAvoidsplinter deposits
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The continuous carrier film is segmented into individual transfer elements with defined separation zones. This ensures that when the carrier film is removed during application, the UV varnish remains contained within each element's boundaries and does not form splinters that could deposit on printing rollers.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The release agent is applied in advance in the separation zones to prevent UV varnish bonding to the carrier film. This preliminary action ensures that during the detachment process, the UV varnish remains intact and does not form splinters.

Inventive Principle:
Principle #10Preliminary action

3Strength

If adhesive layers bond to the carrier film during heat-sealing, then secure attachment is achieved, but detachment becomes difficult causing tearing and spangles

Engineering Contradiction:
Improveattachment strengthVSAvoiddetachment process
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The release agent is applied locally only in the separation zones between security elements, not across the entire carrier film. This allows the adhesive layers to bond strongly to the carrier film in the security element areas for secure attachment, while enabling easy detachment in the separation zones without causing tearing or spangles.

Inventive Principle:
Principle #3Local quality

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 design prevents spangles formation, ensuring clean and smooth breaking edges, reducing defects in printed images, and maintaining the integrity of the printing process by preventing the adhesive layers from tearing and sticking to the carrier film during the heat-sealing process.

Implementation Method 1

a layer of heat-seal adhesive having length H arranged above the functional layer

Methodology Applied
Scientific EffectHeat-sealing: Melting

Implementation Method 2

UV embossing lacquer layer with gaps

Methodology Applied
Scientific EffectUV curing: Photopolymerisation

Data Source

PatentEP2848425B2Strip-shaped continuous film and its use
Publication Date: 2020.03.18 GIESECKE & DEVRIENT CURRENCY TECHNOLOGY GMBH
  • EP2848425B2 patent drawingFigure 1
  • EP2848425B2 patent drawingFigure 2a~2d
  • EP2848425B2 patent drawingFigure 2e~2g

AI summary

Continuous strip film with a front and a back, the front having a plurality of security elements spaced apart from one another in the longitudinal direction of the continuous strip film, each designed as a transfer element removable from the continuous film for application to security paper or a valuable item, and each security element, viewed from the front of the continuous film, having a functional layer with a security feature of length F and a layer of heat-seal adhesive of length H arranged above the functional layer, wherein the lengths F and H are each referred to the longitudinal direction of the continuous strip film and satisfy the relationship F < H, and the functional layer with a security feature and the layer of heat-seal adhesive are such that the functional layer is surrounded by the layer of heat-seal adhesive in a U-shape.