Recyclable Laminated Packaging with Paper-Based Gas Barriers
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Solution Overview
Problem
Existing laminated packaging materials for liquid food containers face challenges in achieving good integrity and internal cohesion while being recyclable, with issues such as air entrapments, blistering, and difficulty in separating layers without significant material loss, particularly due to the use of aluminum foil and high polymer content.
Innovation Solution
A laminated packaging material with a structure comprising a paper or paperboard bulk layer, a gas barrier layer, and an intermediate bonding layer of 5 to 10 g/m² polyethylene, along with outer and inner polymer layers, designed to provide oxygen and water vapor barriers, and allowing for easy recycling by reducing polymer content and improving adhesion without delamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If aluminum foil and high polymer content are used in laminated packaging materials, then good integrity and internal cohesion are achieved, but recyclability deteriorates and material loss increases during separation
Solution Approach 1:
The invention extracts and removes the aluminum foil layer from the laminated packaging structure, replacing it with an all-paperboard construction. This eliminates the problematic metal-polymer composite that causes recycling difficulties and material loss, while maintaining packaging integrity through optimized paperboard layering and bonding mechanisms
Solution Approach 2:
The invention changes the material composition parameters by reducing polymer content and eliminating aluminum foil, transitioning to a paperboard-based structure. This parameter change enables improved recyclability and reduced material loss while maintaining structural integrity through alternative design approaches
2Reliability
If aluminum foil is used as barrier layer, then gas barrier properties are improved, but recyclability deteriorates and carbon footprint increases
Solution Approach 1:
The invention extracts and removes the aluminum foil barrier layer from the packaging structure, replacing it with paperboard-based barrier solutions. This eliminates the non-recyclable metal component while maintaining protective barrier properties through alternative material configurations
Solution Approach 2:
The invention enables complete recovery and recycling of packaging materials by discarding aluminum foil in favor of paperboard construction. This allows the entire packaging structure to be recycled through standard paper recycling processes, improving material recovery rates and reducing carbon footprint
3Strength
If high polymer content is used in intermediate bonding layer, then adhesion strength is improved, but delamination occurs during recycling
Solution Approach 1:
The invention extracts and removes the problematic high-polymer intermediate bonding layer, replacing it with paperboard-to-paperboard bonding mechanisms. This eliminates the polymer-induced delamination issue during recycling while maintaining sufficient adhesion strength through alternative bonding approaches
Solution Approach 2:
The invention achieves material homogeneity by using paperboard throughout the structure, eliminating the heterogeneous polymer-aluminum-paperboard composite. This homogeneous paperboard construction ensures consistent behavior during recycling processes, preventing delamination and enabling complete material recovery
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 ensures effective barrier properties, package integrity, and high fibre yield in recycling, reducing the carbon footprint and maintaining mechanical strength, while avoiding defects like blistering and enabling efficient recycling of materials.
Implementation Method 1
an intermediate bonding layer of polyethylene-based thermoplastic polymer applied via melt extrusion lamination
Implementation Method 2
melt extrusion lamination in an amount of 5 to 10 g/m²
Implementation Method 3
designed to provide oxygen and water vapor barriers
Implementation Method 4
welding together the inner- and outermost heat sealable thermoplastic polymer layers
Data Source
Figure 1
Figure 2a~2b
Figure 2c
AI summary
A laminated packaging material (10) for packaging of liquid or semi-liquid food products comprises as layers of a layer sequence: - an outermost protective material layer (16); - a bulk layer (11) of paper or paperboard or other cellulose-based material; - an intermediate bonding layer (13) of polyethylene-based thermoplastic polymer applied via melt extrusion lamination in an amount of 5 to 10 g/m2; - a gas barrier layer (14) bonded to the bulk layer (11) via the intermediate bonding layer (13), the gas barrier layer (14) comprising a barrier substrate (14a) of paper or paperboard or other cellulose-based material and at least one barrier material coating layer (14b, 14c), the paper barrier substrate (14a) being adjacent to the intermediate bonding layer (13); and - one or more inside polymer layers (18, 19a, 19b), comprising an innermost liquid-tight, heat sealable material layer (19b). A container comprising the laminated packaging material and methods of making and recycling the material and container are also disclosed.