Resealable Packaging Adhesive Segmentation for Gas Tightness

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Solution Overview

Problem

Existing resealable packaging fails to provide sufficient gas tightness, particularly for perishable foods like sausage and cheese, as it allows the escape of gases such as oxygen, nitrogen, or CO2, which compromises the durability of the packaged items.

Innovation Solution

A resealable packaging design featuring a homogeneous top film made of oriented polypropylene with a stable adhesive layer distribution, including a central permanent adhesive region and edge pressure-sensitive adhesive region, and a predetermined breaking line that separates the sealing foil layers, enhancing gas tightness and allowing for easy opening and resealing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a simple lamination process is used to laminate the multi-layered film lid from two individual film layers immediately before being applied to the tray, then the manufacturing complexity is reduced, but the gas tightness against oxygen, nitrogen, and CO2 is insufficient

Engineering Contradiction:
Improvemanufacturing complexityVSAvoidgas tightness
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The adhesive layer is segmented into two distinct functional zones: a permanent adhesive area for initial sealing and a pressure-sensitive adhesive area for resealing. This segmentation allows the packaging to achieve both ease of manufacture through simple lamination and reliable gas tightness through differentiated adhesive functions in different regions of the lid structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different adhesive properties are applied to different local areas of the lid structure. The permanent adhesive provides strong, gas-tight bonding in the central sealing region, while the pressure-sensitive adhesive enables convenient resealing at the edge area. This local differentiation of adhesive quality resolves the contradiction between simple manufacturing and reliable gas tightness.

Inventive Principle:
Principle #3Local quality

2Ease of operation

If a predetermined breaking line is introduced through the top film and sealing film, then the packaging can be easily opened and resealed, but the mechanical stability and gas tightness of the sealed state are compromised

Engineering Contradiction:
Improveopening and resealing convenienceVSAvoidgas tightness in sealed state
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The breaking line is strategically positioned to pass only through the sealing film and not through the top film, creating a segmented failure path. This allows the packaging to be easily opened by tearing along the breaking line while maintaining the integrity and gas tightness of the top film and permanent adhesive bonding in the sealed state.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The adhesive layer acts as an intermediary element that bridges the top film and sealing film. By positioning the breaking line to pass through the sealing film while maintaining permanent adhesive bonding, the system enables easy opening through controlled tearing while preserving gas tightness through the adhesive-mediated connection in the sealed state.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Stability of the object's composition

If the top film is made homogeneous and stable without predetermined breaking lines up to the outer edge, then the mechanical rigidity and stability are improved, but the ease of opening and resealing is reduced

Engineering Contradiction:
Improvemechanical stability of top filmVSAvoidopening and resealing ease
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The top film structure is segmented into a homogeneous stable region extending to the outer edge for mechanical stability, and a detachable edge strip region containing the breaking line for ease of opening. This segmentation allows the majority of the top film to maintain homogeneous stability while the edge portion enables convenient opening and resealing operations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different structural qualities are applied locally: the main body of the top film is made homogeneous and stable for mechanical strength, while the edge area incorporates a breaking line through the sealing film to enable easy opening. This local differentiation of structural quality resolves the contradiction between overall stability and localized ease of operation.

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

The solution significantly improves gas tightness, preventing gas exchange and ensuring the long-term durability of packaged foods by maintaining a high gas density in the sealed state while allowing for comfortable and easy opening and resealing.

Implementation Method 1

the adhesive layer has an inner central area in which the top film is permanently bonded to the sealing film by means of a permanent adhesive

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Implementation Method 2

an outer edge area is further provided in which, at least in the sections where the top film is to detach from the sealing film, the top film and sealing film are detachably and resealed together by means of an adhesive, in particular a pressure-sensitive adhesive (PSA)

Methodology Applied
Scientific EffectPressure-sensitive adhesive bonding: Adhesive

Data Source

PatentEP2347972B1Resealable packaging
Publication Date: 2021.09.22 AMCOR FLEXIBLES KREUZLINGEN LTD
  • EP2347972B1 patent drawingFigure 1~2b
  • EP2347972B1 patent drawingFigure 3~4
  • EP2347972B1 patent drawingFigure 5

AI summary

The package has a film cover (3) a sealing film (7) freely supported as a layer stack construction on edge strips (2) of a bowl (1), and a top film (6) extending to an outer edge of the edge strips. The top film and the sealing film are attached with each other by an adhesive layer (8). Permanent adhesive is provided on an inner central region (10) of the adhesive layer, and reclosure enabling pressure sensitive adhesive is provided on an outer boundary region (11) of the adhesive layer. A break line (9) is provided between the outer boundary region and the inner central region. The sealing film is provided with a barrier layer that is impermeable for air, oxygen and carbon dioxide. The barrier layer comprises an oxide layer e.g. aluminum oxide layer, silicon oxide layer and polyamide layer. The bowl is made of a composite material such as plastic. Independent claims are also included for the following: (1) a prefabricated multi-layer film for producing a resealable package (2) a method for packing sliced food products.