Composite Hinge Sheet for Laser-Markable Electronic Passport Laminate

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Solution Overview

Problem

Existing electronic passport laminates face issues with thermal adhesiveness, durability, and resistance to falsification and forgery, as well as challenges in achieving clear and high-contrast laser markings without damage to the surface.

Innovation Solution

A composite hinge sheet for a laser-markable multilayer laminate is developed, featuring a woven-fabric like sheet with integrated thermoplastic resin layers, providing excellent thermal adhesiveness, dimension accuracy, and resistance to bending, along with a laminated structure that includes transparent polycarbonate resin layers for improved transparency and contrast.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional laminate structure is used for electronic passports, then the basic structural requirements are met, but thermal adhesiveness is insufficient and durability against falsification is poor

Engineering Contradiction:
Improveresistance to falsification and forgeryVSAvoidthermal adhesiveness
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent employs a composite hinge sheet structure consisting of a woven-fabric like sheet (providing dimensional stability and tear resistance) combined with thermoplastic resin layers (providing thermal adhesiveness). This composite structure simultaneously achieves high reliability against falsification through the woven fabric's mechanical strength and excellent thermal adhesiveness through the resin layers' bonding properties, resolving the contradiction between durability and ease of manufacture.

Inventive Principle:
Principle #40Composite materials

2Reliability

If the laminate structure is designed for durability and resistance to damage, then reliability is improved, but the ability to achieve clear high-contrast laser markings is compromised

Engineering Contradiction:
ImprovedurabilityVSAvoidlaser marking clarity and contrast
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by differentiating the properties of different layers: the woven-fabric like sheet provides durability and dimensional stability in regions requiring mechanical strength, while the thermoplastic resin layers provide laser markability and surface smoothness in regions requiring clear markings. This spatial differentiation of material properties allows the laminate to simultaneously achieve high durability and excellent laser marking clarity with high contrast.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If thermoplastic resin layers are integrated with the woven-fabric like sheet to improve thermal adhesiveness, then manufacturing ease is improved, but the complexity of the laminate structure increases

Engineering Contradiction:
Improvethermal adhesivenessVSAvoidlaminate structure complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent merges the hinge sheet function with the laser-markable laminate structure by integrating thermoplastic resin layers directly with the woven-fabric like sheet to form a composite hinge sheet. This integration combines multiple functions (hinge flexibility, thermal adhesion, dimensional stability) into a single composite component, reducing the number of separate parts and assembly steps despite the enhanced structural complexity at the material level.

Inventive Principle:
Principle #5Merging (Combining)

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 enhances the reliability of electronic passports by preventing falsification and forgery, ensuring clear and durable laser markings with high contrast, while maintaining thermal resistance and foldability.

Implementation Method 1

a composite hinge sheet including thermoplastic resin layers on both faces of a woven-fabric like sheet... excellent thermal adhesiveness

Methodology Applied
Scientific EffectThermal adhesion: Heating

Implementation Method 2

transparent polycarbonate resin layers for improved transparency and contrast

Methodology Applied
Scientific EffectLight transmission: Light

Implementation Method 3

laser-markable multilayer laminate... capable of being marked thereon by laser beam irradiation

Methodology Applied
Scientific EffectLaser heating: Laser

Data Source

PatentEP2487029B1Composite hinge sheet for laser-markable multilayer laminate for electronic passport, laser-markable multilayer laminate for electronic passport, electronic passport, method for manufacturing a composite hinge sheet, and use of a molten thermoplastic resin
Publication Date: 2019.07.31 MITSUBISHI CHEM CORP
  • EP2487029B1 patent drawingFigure 1~4
  • EP2487029B1 patent drawingFigure 5~6
  • EP2487029B1 patent drawingFigure 7

AI summary

Disclosed is a composite hinge sheet including thermoplastic resin layers 5 made of a thermoplastic resin formed on both surfaces of a woven-fabric like sheet 3 having multiple openings therein. The woven-fabric like sheet 3 includes woven fabric or non-woven fabric made of at least one type selected from polyester, polyamide and polypropylene. The thermoplastic resin layers 5 include, as a raw material, resin having Shore A surface hardness flexibility of 85 or greater and Shore D surface hardness flexibility of less than 70. A part of the thermoplastic resin enters the openings in the woven-fabric like sheet 5, thus blocking all the openings, so that the thermoplastic resin layers 5 are integrated with the woven-fabric like sheet 3. The composite hinge sheet has excellent tearing and tensile strength, is resistant to light and heat in the binding part thereof, and has excellent resistance to repeated bending.