Card-Based Container Sealing Structure for Higher Recyclability

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Solution Overview

Problem

Existing card-based containers, particularly those used for food packaging, face challenges in achieving high recyclability due to the combination of hygiene and heat-sealing functions in a single polymer layer, making them difficult to recycle effectively.

Innovation Solution

A card-based container design with a predominantly cellulose outer structural layer, a thin inner hygienic layer, and localized heat-sealable polymer strips, minimizing the use of non-paper materials and allowing for easier recycling by separating the hygiene and sealing functions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single polymer layer is used to combine hygiene and heat-sealing functions, then sealing effectiveness is improved, but recyclability deteriorates due to difficulty in separating layers

Engineering Contradiction:
Improvesealing effectivenessVSAvoidrecyclability
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent divides the previously combined hygiene and heat-sealing functions into separate components: a thin inner hygienic layer (less than 20 microns) and localized sealing strips applied only at connection locations. This segmentation allows the hygienic layer to be easily separated for recycling while the sealing strips provide the necessary sealing function where needed.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The sealing strips are applied locally only at connection locations where the sidewall seals to itself or to end closures, rather than covering the entire surface. This localized approach reduces the overall amount of polymer material while maintaining sealing effectiveness at critical points, thereby improving recyclability.

Inventive Principle:
Principle #3Local quality

2Reliability

If a thicker polymer layer is used for heat sealing, then sealing reliability is improved, but the amount of non-paper material increases making recycling more difficult

Engineering Contradiction:
Improvesealing reliabilityVSAvoidamount of non-paper material
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The sealing strips are applied locally only at connection locations where sealing is required, rather than using a continuous thick polymer layer across the entire container surface. This localized application maintains sealing reliability at critical points while minimizing the total quantity of non-paper material in the package.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The sealing function is segmented into discrete strips rather than a continuous layer, allowing the minimum necessary amount of polymer material to be used while still achieving reliable sealing at each connection point.

Inventive Principle:
Principle #1Segmentation

3Reliability

If more polymer material is used to ensure hygiene function, then hygiene effectiveness is improved, but environmental impact worsens due to reduced recyclability

Engineering Contradiction:
Improvehygiene effectivenessVSAvoidenvironmental impact
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The thickness parameter of the inner hygienic layer is reduced to less than 20 microns, which is sufficient to maintain hygiene effectiveness while significantly reducing the amount of non-recyclable polymer material. This parameter change balances hygiene requirements with environmental sustainability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The hygienic function is separated from the sealing function, with the thin hygienic layer providing barrier protection and the localized sealing strips providing seal integrity. This segmentation allows the hygienic layer to be optimized for minimal thickness while maintaining effectiveness.

Inventive Principle:
Principle #1Segmentation

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 design enhances recyclability by reducing the overall non-paper content, enabling the container to be processed with paper-based products, while maintaining hygiene and sealing effectiveness.

Implementation Method 1

the sealing strips comprising a heat-sealable polymer

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 2

sealed to the sidewall to form a hermetically sealed package

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP4496750B1Sealable card based container and blank therefor
Publication Date: 2026.04.15 NV NUTRICIA
  • EP4496750B1 patent drawingFigure 1~2
  • EP4496750B1 patent drawingFigure 3~4
  • EP4496750B1 patent drawingFigure 5~7

AI summary

A card based container has a tubular sidewall of laminate material and first and second end closures, sealed to the tubular sidewall to form a hermetically sealed package. The sidewall comprises an outer card layer, an inner hygienic layer and one or more sealing strips provided at an inner surface of the inner hygienic layer, located at connection locations where the sidewall seals to itself or to the respective end closures. The sealing strips comprises a heat-sealable polymer. The overall amount of non-paper content in the sidewall and in the package may thus be reduced.