Induction Heat Sealable Closure Liner for Paper Recycling
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Solution Overview
Problem
Existing induction heat seal liners are not recyclable in paper or plastic recycling streams due to the presence of metal layers and mixed composite structures, leading to non-recyclable trash and potential delamination issues during peeling.
Innovation Solution
A composite layer structure for induction heat-sealable closure liners comprising a paperboard layer, a metal foil layer for inductive heating, and a heat sealant coating, where the metal foil layer is disposed between the paperboard layer and the heat sealant coating, allowing for recyclability in a paper recycling stream while maintaining tamper evidence and barrier properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a metal foil layer is added to enable induction heat sealing, then heat sealability is improved, but recyclability deteriorates
Solution Approach 1:
The liner is divided into distinct functional layers: a recyclable paperboard base layer and a metal foil layer for heat sealing. This segmentation allows the paperboard layer to be recovered and recycled separately in paper recycling streams, while the metal layer performs its heat sealing function during use.
Solution Approach 2:
The metal foil layer is extracted as a separate component that can be removed and recovered from the paper recycling stream. The paperboard layer is designed to be the primary recyclable component, with the metal layer serving as a functional additive that does not prevent overall recyclability of the paper portion.
2Reliability
If multiple layers are combined to provide barrier properties, then product protection is improved, but recycling complexity increases
Solution Approach 1:
The liner uses a composite structure combining paperboard and metal foil layers, where each material contributes its superior properties: paperboard provides recyclability and structural integrity, while metal foil provides heat sealability and barrier properties. This composite approach achieves multiple functions without excessive complexity.
3Stability of the object's composition
If adhesive layers are added to prevent delamination, then structural stability is improved, but recyclability deteriorates
Solution Approach 1:
Adhesive or barrier coatings are applied locally at specific interfaces between layers rather than throughout the entire structure. This localized approach provides necessary structural stability at critical junctions while minimizing the amount of non-recyclable material, allowing the paperboard layer to remain predominantly recyclable.
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 enables the entire liner to be recycled in a paper recycling stream, maintaining product integrity and barrier properties, extending shelf life, providing tamper evidence, preventing leakage and contamination, and reducing waste generation.
Implementation Method 1
a metal foil layer (130) for inductive heating
Implementation Method 2
metal foil layer (130) for inductive heating
Data Source
AI summary
A laminated multi-layer liner or lidding structure, including non-paper components, that allows consumers to recycle the entire liner or lidding in a paper recycling stream. As a result, manufacturers currently selling products without liners will now be able to include liners on their containers and provide a totally recyclable container package, including the container, cap and liner (each recyclable in a respective plastic or paper recycling stream), while providing the benefits that liners provide, including maintaining product integrity and barrier properties, extending shelf life, providing tamper evidence, preventing leakage, preventing products from being contaminated and/or damaged by consumers sampling the products, and/or otherwise creating an un-saleable product due to leakage, contamination or damage.