Secure Document Substrate with Fumed Silica Coating for Intaglio Printability

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Solution Overview

Problem

Secure documents with iridescent layers face challenges during intaglio printing due to transfer issues and mechanical deterioration, requiring a composition that maintains shine while ensuring good printability and resistance to handling.

Innovation Solution

A composition incorporating fumed colloidal silica as a nanometric filler, combined with reflective particles, enhances printability and gloss, and is resistant to mechanical stress, allowing for effective intaglio microprinting and circulation without compromising the shine effect.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If an iridescent composition layer is applied to provide high gloss and security, then the document's appearance and security are enhanced, but the layer transfers to printing plates during intaglio printing

Engineering Contradiction:
Improvegloss levelVSAvoidprintability
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

A polymeric overlay is applied over the iridescent composition layer to serve as a protective intermediary. This overlay prevents the iridescent layer from transferring to printing plates during intaglio printing while preserving the gloss and visual effects. The overlay acts as a barrier that mediates between the iridescent layer and the printing process.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Strength

If the iridescent composition layer is made resistant to mechanical stress, then durability during handling is improved, but print quality and sharpness deteriorate

Engineering Contradiction:
Improvemechanical resistanceVSAvoidprint sharpness
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The coating structure is segmented into distinct functional layers: an iridescent composition layer for visual effects and a separate polymeric overlay for mechanical protection. This segmentation allows each layer to be optimized independently - the overlay provides durability without interfering with the print sharpness achieved on the underlying layer.

Inventive Principle:
Principle #1Segmentation

3Reliability

If a polymeric overlay is applied to prevent transfer and improve durability, then printability and mechanical resistance are enhanced, but the gloss level and visual appeal are reduced

Engineering Contradiction:
ImproveprintabilityVSAvoidgloss level
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

The polymeric overlay is formulated with specific parameters - transparency and controlled thickness - to minimize its impact on gloss. By adjusting these parameters, the overlay provides protective functions while allowing the underlying iridescent layer's visual effects and gloss to remain visible and appealing.

Inventive Principle:
Principle #35Parameter changes

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 composition achieves high gloss and print clarity, maintaining the shine effect while ensuring good resistance to mechanical stress and handling, making it suitable for secure documents.

Implementation Method 1

A composition incorporating fumed colloidal silica as a nanometric filler, combined with reflective particles, enhances printability and gloss

Methodology Applied
Scientific EffectNanometric filler effect:

Implementation Method 2

A composition incorporating fumed colloidal silica as a nanometric filler, combined with reflective particles, enhances printability and gloss

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 3

A composition incorporating fumed colloidal silica as a nanometric filler, combined with reflective particles, enhances printability and gloss, and is resistant to mechanical stress

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3149243B1Substrate for secure document
Publication Date: 2024.08.14 OBERTHUR FIDUCIAIRE SAS
  • EP3149243B1 patent drawingFigure 1~3

AI summary

The invention relates to a substrate at least partially coated on at least one of the surfaces thereof with a composition comprising reflecting particles and a nanoscale filler.