Compensating Layer for Secure Booklet Flap Bonding

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Solution Overview

Problem

Existing data pages for book-like documents, such as passports, face challenges in achieving a non-detachable connection between the front and back booklets, particularly when incorporating a flexible strap, as existing methods lack a strong and permanent adhesive connection.

Innovation Solution

Incorporating a flexible flap with a compensating layer of lower glass transition temperature than the adjacent layers, which softens during lamination to enhance adhesive connection and is pressed into the adjacent layers for a stronger bond, using materials like polycarbonate or polyethylene terephthalate, and employing techniques like heat and pressure lamination or ultrasonic welding for fixation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a flexible flap is incorporated between front and back booklets, then the document functionality is improved, but achieving a non-detachable connection becomes difficult

Engineering Contradiction:
Improvedocument functionalityVSAvoidconnection permanence
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

A compensating layer with lower glass transition temperature is introduced as an intermediary between the flexible flap and the adjacent booklet layers. This compensating layer has different thermal properties (lower Tg) that enable it to soften and flow during lamination at standard temperatures, filling gaps and creating strong adhesive bonds, while the adjacent layers with higher Tg maintain their structural integrity. This mediator layer resolves the contradiction by enabling permanent connection without requiring extreme temperatures that would damage the flexible flap.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention utilizes parameter changes in the glass transition temperature (Tg) of different layers to achieve the desired effect. The compensating layer is specifically selected or engineered to have a lower Tg than the adjacent booklet layers, allowing it to undergo rheological changes at lamination temperatures. This parameter differentiation enables the compensating layer to become adhesive and flowable during processing, creating permanent bonds, while the higher Tg adjacent layers remain dimensionally stable and provide structural support throughout the process.

Inventive Principle:
Principle #35Parameter changes

2Shape

If standard lamination temperature is used, then the flexible flap structure is preserved, but adhesive connection is insufficient

Engineering Contradiction:
Improveflap structureVSAvoidadhesive connection
Core Design Contradiction:
ShapeVSStrength

Solution Approach 1:

The invention applies local quality by creating spatial differentiation in thermal properties across the layered structure. The compensating layer positioned locally between the flexible flap and booklet layers has a lower glass transition temperature specifically at that interface region. This localized parameter variation enables adhesive bonding to occur at standard lamination temperatures without requiring global temperature increases that would compromise the flexible flap's structural integrity. The local quality approach allows different regions of the composite to have optimized properties for their specific functions.

Inventive Principle:
Principle #3Local quality

3Strength

If higher temperature is applied during lamination, then adhesive connection improves, but the flexible flap material degrades

Engineering Contradiction:
Improveadhesive connectionVSAvoidmaterial degradation
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The compensating layer acts as a thermal mediator that protects the flexible flap from degradation. With its lower glass transition temperature, the compensating layer absorbs and dissipates thermal energy at the bonding interface, preventing heat buildup that would otherwise reach and degrade the flexible flap material. This intermediary layer enables sufficient thermal energy to be applied for strong adhesive bonding while simultaneously protecting the temperature-sensitive flexible flap from harmful thermal effects.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention exploits parameter changes in glass transition temperature to create a thermal buffer zone. The compensating layer's lower Tg creates a gradient in thermal sensitivity across the laminate structure, allowing the system to operate at temperatures that are sufficient for bonding (affecting the low Tg compensating layer) but below the degradation threshold of the high Tg flexible flap material. This parameter differentiation resolves the contradiction between achieving strong bonds and preventing material degradation.

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

This approach results in a permanent, reinforced, and non-detachable connection between the front and back booklets, ensuring a robust and secure laminate composite with improved handling and integration of security features like transponder modules.

Implementation Method 1

the at least one compensating layer comprises a glass transition temperature which is lower than the glass transition temperature of the adjacent layers or pressure layers

Methodology Applied
Scientific EffectGlass transition:

Implementation Method 2

during the lamination of the front and back booklet with the integration of the flap and the compensation layer

Methodology Applied
Scientific EffectLamination: Lamination

Implementation Method 3

when laminating the individual superimposed layers of the front and back booklet, the flap is pressed more strongly into the adjacent layer or pressure layer

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP2981416B1Data page for a book-like document and method for producing such a data page
Publication Date: 2017.12.20 BUNDESDRUCKEREI GMBH
  • EP2981416B1 patent drawingFigure 1~2
  • EP2981416B1 patent drawingFigure 3~4

AI summary

The invention relates to a data page for a book-like document and a method for producing a data page, more particularly a personalized data page for a book-like document, comprising a front-side booklet (28), which has at least one layer (35, 36, 37, 41) or a pressure layer (33), comprising a back-side booklet (29), which has at least one layer (43, 44, 47) or a pressure layer (45), and comprising a tab (23) made of a flexible layer, which comprises a region (50) protruding between the front and back-side booklets (28, 29), and a region (49) protruding opposite thereto, to which the data page (17) in the document (11) can be secured, and comprising at least one compensation layer (31) provided between the front-side booklet (28) and the back-side booklet (29) which extends to the tab (23), characterized in that the at least one compensation layer (31) consists of a plastic layer having a glass transition temperature which is lower than the glass transition temperature of the layers (41, 47) adjacent thereto or pressure layers (33, 45) of the front-side booklet (28) and the back-side booklet (29).