Laminated Polymer Packaging Recycling with Selective PET Dissolution
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Solution Overview
Problem
Current recycling processes for laminated polymer packaging are ineffective in separating and reusing PET, PE, and PP due to their differing physical characteristics, and existing methods fail to address non-metallic laminates without a metallic layer, leading to environmental pollution and waste.
Innovation Solution
A recycling process using ethylene glycol-based baths for selective dissolution of PET, followed by melting PE and PP in heterogeneous phases, allowing for the separation and reuse of these materials independently, with aluminum collected as a precipitate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional thermoplastic reprocessing is used for laminated packaging, then processing simplicity is maintained, but separation of incompatible polymers (PET, PE, PP) is impossible
Solution Approach 1:
The patent introduces an alkaline medium (NaOH solution) as an intermediary substance that selectively dissolves PET at the lamination interface, enabling separation of PET from PE and PP without requiring complex mechanical or manual sorting processes. The chemical mediator facilitates selective decomposition of specific polymer bonds while leaving others intact.
Solution Approach 2:
The process utilizes changes in chemical parameters (pH, temperature, concentration of alkaline solution) to achieve selective dissolution of PET. By controlling these parameters, the process selectively targets PET for decomposition while preserving PE and PP, enabling precise polymer separation based on their differing chemical reactivity.
2Manufacturing precision
If existing recycling processes target metallic layers, then aluminum separation is achieved, but polymeric compounds require additional processing and non-metallic laminates are not addressed
Solution Approach 1:
The alkaline dissolution process serves multiple functions simultaneously: it dissolves metallic aluminum layers, separates PET from other polymers, and treats both metallic and non-metallic laminated packaging. This multi-functional approach eliminates the need for separate processing lines for different packaging types, reducing overall process complexity.
Solution Approach 2:
The process extracts and removes aluminum and PET from the laminated structure through selective chemical dissolution. By taking out these components in a single integrated process step, the method avoids multiple sequential operations and directly produces separable polymer fractions without requiring additional processing equipment.
3Adaptability or versatility
If PET and aluminum are combined in packaging, then packaging functionality is enhanced, but physical characteristics differ making reuse of PE or PP impossible
Solution Approach 1:
The patent replaces mechanical separation methods with chemical dissolution to separate polymers. Instead of using mechanical forces that would require compatible physical properties of polymers, the chemical process selectively dissolves PET based on its chemical structure, enabling separation of polymers with vastly different mechanical and physical characteristics.
4Adaptability or versatility
If multilayer laminated packaging is used, then packaging performance is improved, but recycling effectiveness decreases and environmental pollution increases
Solution Approach 1:
The process recovers valuable polymers (PE, PP, PET) from what would otherwise be discarded as non-recyclable waste. By chemically separating and recovering these materials in usable forms, the process transforms environmental pollutants into recoverable resources, enabling circular economy applications for multilayer packaging.
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
Enables complete separation and reuse of PET, PE, and PP in a circular economy, with minimal material loss, and recovers aluminum in its metallic form, enhancing economic viability and environmental sustainability.
Implementation Method 1
achieves the complete separation of PET (polyethylene terephthalate) through its selective dissolution in the medium
Implementation Method 2
a process comprising ethylene glycol in its mono-, di- or tri-forms is applied, allowing the dissolution of the packaging's polyester films
Implementation Method 3
the separation of PE (polyethylene) and PP (polypropylene) through its complete melting, in a system of heterogeneous phases
Implementation Method 4
immersion (2) of the polymeric packaging (E) in an ethylene glycol bath... heating the reactor via a coil, raising the temperature of the glycol to a range between 180 °C and 240 °C
Implementation Method 5
aluminium, if present, can be collected in its metallic form through the formation of a precipitate (decantation)
Implementation Method 6
aluminium, if present, can be collected in its metallic form through the formation of a precipitate (decantation)
Data Source
Figure 1
AI summary
"PROCESS FOR RECYCLING LAMINATED POLYMERIC PACKAGING USING ETHYLENE GLYCOL" applied in polymeric packaging containing one or more materials from a group formed by PP, PE, PET and aluminium; said process being comprising performing the selective dissolution of PET, reusing it as a product of its reaction with glycol, as well as separating aluminium in its metallic form and PP and PE as a supernatant portion in said product.