Casein-Based Two-Part Seals for Heat-Free Container Recycling

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Solution Overview

Problem

Existing seals for containers require heating or gluing for sealing, complicating recycling and potentially violating food safety regulations, and they are not biodegradable.

Innovation Solution

A casein-based film is used for sealing containers without heating or gluing, which is biodegradable and recyclable, and can be combined with a reinforcing film for added strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If heating or gluing is used for sealing the lid on the container rim, then sealing reliability is improved, but device complexity and food safety compliance worsen due to required conductive materials and additional processes

Engineering Contradiction:
Improvesealing reliabilityVSAvoidsealing process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention removes the conductive material layer from the lid structure, eliminating the need for heating or gluing processes. The seal relies solely on the mechanical compression of the foam support against the container rim, simplifying both the device structure and the sealing process while maintaining reliability through the elastic memory effect of the foam material.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of manufacture

If conductive material is inserted into the lid for heat sealing, then heat sealing capability is improved, but recyclability worsens due to separation requirements

Engineering Contradiction:
Improveheat sealing capabilityVSAvoidrecycling efficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The conductive material layer is completely removed from the lid structure. The sealing function is achieved through the mechanical compression of the foam support material against the container rim, eliminating the need for heat sealing and thereby simplifying the recycling process as the entire lid can be processed without material separation.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If glue is applied to seal the lid on the rim, then sealing reliability is improved, but food safety compliance worsens due to potential glue penetration into the container

Engineering Contradiction:
Improvesealing reliabilityVSAvoidfood safety risk
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention eliminates the use of glue or any adhesive substances in the sealing process. The seal is formed purely by the mechanical compression of the foam support against the container rim, which then maintains the seal through its elastic memory effect. This removes any risk of adhesive penetration into the container and potential contamination of the contents.

Inventive Principle:
Principle #2Taking out (Extraction)

4Productivity

If a casein-based film is used for sealing, then biodegradability and recyclability are improved, but sealing strength may worsen without additional reinforcing measures

Engineering Contradiction:
Improvebiodegradability and recyclabilityVSAvoidsealing strength
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The lid is constructed as a composite structure combining a casein-based film layer with a foam support layer. The casein film provides the sealing interface against the container rim, while the foam support provides mechanical strength and elastic compression. This composite structure maintains sealing strength while ensuring biodegradability and recyclability of the entire assembly.

Inventive Principle:
Principle #40Composite materials

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 casein-based film allows for recyclable and biodegradable sealing without the need for conductive materials, ensuring food safety compliance and efficient recycling.

Implementation Method 1

The sealing of the lid on the rim is carried out by gluing or induction heat sealing

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

It is therefore capable of ensuring a certain compression with memory effect to allow these tolerances to be absorbed

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 3

this is made possible by the combined action of a conductive material, inserted into the thickness of the seal, which, under the effect of electrical induction, heats up

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 4

which, under the effect of electrical induction, heats up, causing the softening of the sealing film

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP4414289B1Two-part seal comprising a casein-based lid and casein-based lid
Publication Date: 2025.10.22 SELIG FRANCE
  • EP4414289B1 patent drawingFigure 1~2
  • EP4414289B1 patent drawingFigure 3~4

AI summary

Double-piece seal comprising a support made integral to a lid by means of a temporary adhesive characterized in that the lid comprises a casein and/or caseinate-based film intended to be in contact with the drinking vessel of said container.