Multilayer Polymer Separation Using Solvent-Non-Solvent Swelling
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Solution Overview
Problem
Multilayer plastic packaging structures are difficult to separate or recycle due to their complex composition, leading to environmental pollution and waste, as existing methods often require harsh chemicals and energy-intensive processes that degrade polymers.
Innovation Solution
A method involving a treatment solution comprising a solvent and a non-solvent is used to swell and separate polymer layers from multilayer structures without dissolving them, allowing for recovery and reuse of the polymers, and enabling safer, more energy-efficient recycling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional mechanical recycling methods (shredding, milling, sieving, centrifugation) are used, then polymer particles can be recovered from single-layer plastics, but these methods cannot separate polymers from multilayer packaging structures
Solution Approach 1:
The patent introduces a treatment solution as an intermediary substance that selectively interacts with the adhesive layer in multilayer packaging. This solution contains a solvent that dissolves the adhesive and a non-solvent that precipitates the polymer, enabling separation without requiring complex mechanical processing. The intermediary treatment solution allows the system to handle multilayer structures that traditional mechanical methods cannot process.
2Productivity
If organic solvents (benzene, dichloromethane, xylene, toluene, carbon tetrachloride, chloroform) are used to delaminate and dissolve polymers, then polymer separation can be achieved, but the process requires harsh chemicals and energy-intensive recovery operations
Solution Approach 1:
The patent changes the parameters of the treatment solution by using a specific combination of solvent and non-solvent in controlled proportions. The solvent is selected to dissolve the adhesive layer while the non-solvent causes polymer precipitation. This parameter optimization allows the process to proceed under milder conditions with lower energy consumption compared to traditional methods that require high-temperature evaporation and complex recovery systems.
Solution Approach 2:
The patent converts the potentially harmful effect of using solvents into a beneficial process by carefully selecting a solvent-non-solvent pair where the solvent dissolves the adhesive (enabling separation) while the non-solvent component simultaneously causes polymer precipitation (simplifying recovery). This transforms what would normally be a harmful chemical process into a beneficial separation process with automatic polymer recovery.
3Productivity
If enzymes are used to degrade polymers into monomers or oligomers, then polymer recovery can be achieved, but the process requires specific enzymatic conditions and may not be applicable to all polymer types in multilayer structures
Solution Approach 1:
The patent uses a chemical treatment solution as an intermediary that directly addresses the adhesive layer without requiring enzymatic degradation of the polymer layers. This chemical approach is more universally applicable to different polymer types in multilayer packaging, as it targets the adhesive component rather than requiring specific enzymatic actions on various polymer materials. The treatment solution acts as a universal mediator that works across different polymer compositions.
4Object-affected harmful factors
If ionic liquids or deep eutectic solvents are used for polymer recovery, then alternative to traditional solvents can be achieved, but these methods still require complex recovery processes and specialized equipment
Solution Approach 1:
The patent extracts the adhesive layer from the multilayer packaging structure using a treatment solution, thereby separating it from the polymer layers. This extraction approach simplifies the overall process by removing only the adhesive component rather than requiring complex recovery systems for entire polymer matrices. The treatment solution selectively extracts the adhesive, leaving the polymer layers intact and easily separable through simple filtration or decantation.
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 method effectively separates polymer layers from other materials in multilayer structures with minimal degradation, facilitating the recovery of high-quality polymers and enabling a safer, more environmentally friendly recycling process.
Implementation Method 1
The inventors have surprisingly found that a treatment solution comprising a solvent and a non-solvent may be used to separate a polymer layer from another layer in a multilayer structure. The presence of the non-solvent in the treatment solution is believed to prevent the solvent from dissolving the polymer layer, but still allow the solvent to swell the polymer layer
Data Source
AI summary
A method for separating a first layer from a second layer in a multilayer structure is disclosed. The method comprises the step of contacting the multilayer structure with a treatment solution comprising a solvent and a non-solvent until the first layer is separated from the second layer. The first layer comprises a polymer, wherein the polymer is soluble in the solvent and the polymer is insoluble in the non-solvent. The separated layer, an article comprising the separated layer, and a use of the treatment solution to separate the first layer from the second layer in the multilayer structure are also disclosed.