Security Bag Tamper Detection via Dual-Layer Adhesive and Cold Indicator

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Solution Overview

Problem

Conventional security bags can be accessed and resealed without visible indication of tampering, particularly when a cold spray is used to reduce the adhesive effect from the backside, bypassing integrated tamper indicators.

Innovation Solution

Incorporating an additional indicator element on the lower layer, which irreversibly changes color or dissolves upon exposure to cold temperatures and moisture, ensuring that any attempt to access the bag through cooling or moisture is visibly detected.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a closure strip with adhesive layer is used to seal the security bag, then the bag can be closed securely, but the adhesive effect can be reduced by cooling from the backside allowing unauthorized access

Engineering Contradiction:
Improvesealing reliabilityVSAvoidvulnerability to cold spray attack
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies a double-sided adhesive layer that extends beyond the closure strip edges, creating an overlapping adhesive zone on the bag body. This excessive extension ensures that even if the closure strip is compromised by cooling, the extended adhesive portions maintain sealing integrity and prevent unauthorized access.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The adhesive layer is extended from the one-dimensional closure strip into the two-dimensional bag surface, creating an overlapping zone that spans across the closure strip edges. This dimensional extension creates a redundant sealing path that is not directly affected by localized cooling of the closure strip.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If tamper indicators are integrated into the closure strip, then tampering can be detected, but indicators on the closure strip can be bypassed by cooling from the backside

Engineering Contradiction:
Improvetamper detection capabilityVSAvoidbypass vulnerability through backside cooling
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The adhesive layer extends beyond the closure strip boundaries, creating an overlapping zone that is not directly controlled by closure strip temperature changes. This excessive extension creates a detection zone that is spatially separated from the closure strip tamper indicators, preventing bypass through localized cooling.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The extended adhesive layer acts as an intermediary detection zone between the closure strip and the bag interior. This intermediate adhesive zone provides an additional layer of security that can detect tampering attempts independent of the closure strip indicators, serving as a mediator that prevents direct bypass.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If the adhesive layer is cooled to reduce its adhesive effect, then access to the interior can be gained, but this creates a security vulnerability

Engineering Contradiction:
ImproveaccessibilityVSAvoidsecurity integrity
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The adhesive layer extends beyond the closure strip to create an overlapping zone that remains unaffected by localized cooling attempts. This excessive extension ensures that even if part of the adhesive is cooled and its effect reduced, the extended portions maintain sufficient adhesive strength to preserve security integrity.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The extended adhesive layer serves as a pre-positioned cushioning measure against cooling attacks. By having adhesive material already in place beyond the closure strip boundaries, the system is pre-prepared to resist tampering attempts that involve cooling, maintaining security without requiring additional active defenses.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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

Prevents unauthorized access by providing an irreversible indication of tampering attempts, ensuring the security bag's integrity is maintained even when cooled from the underside.

Implementation Method 1

The actual cold indicator can be formed by a varnish which changes its color preferably irreversibly when exposed to a specific temperature and/or humidity below 0°C

Methodology Applied
Scientific EffectThermochromism: Thermochromism

Implementation Method 2

When the cold spray is sprayed onto a corresponding indicator element or a corresponding plastic band, fine water droplets are formed which cause the material of the indicator element or the plastic band to dissolve at least locally

Methodology Applied
Scientific EffectDissolution: Solvation

Implementation Method 3

Excessive cooling of the adhesive layer loses its adhesive effect, so that the closure strip can be lifted and valuables can be removed from the interior of the security bag through the slit-shaped opening

Methodology Applied
Scientific EffectAdhesive degradation: Adhesive

Data Source

PatentEP3016871B1Security bag
Publication Date: 2017.04.19 HM SERVICES
  • EP3016871B1 patent drawingFigure 1
  • EP3016871B1 patent drawingFigure 2
  • EP3016871B1 patent drawingFigure 3

AI summary

The invention relates to a security bag for transporting valuables, having an upper first layer and a lower second layer, each of which consists of a flat plastic material. A slot-shaped opening which can be closed by a closure device is formed in the first layer. The closure device comprises a closure strip and an adhesive layer arranged between the closure strip and the first layer. At least one indicator element is arranged on the lower second layer in the region of the closure device, said indicator element irreversibly indicating a drop in the surrounding temperature to a value below 0 °C and/or an exposure to moisture.