Thermoplastic Recycling via Low-Temperature Depolymerization
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Solution Overview
Problem
Current recycling methods for thermoplastic resins and composite materials are inefficient in terms of energy consumption and processing time, and often result in thermal degradation of materials and unsatisfactory yield and quality of reusable monomers.
Innovation Solution
A process involving local heating of thermoplastic polymer resin to convert it into polymers of lower molar mass, which can then be dissolved in their base monomers, using techniques such as pulsed electric fields or microwaves, to facilitate recycling while minimizing energy consumption and preserving material quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If thermal pyrolysis is used to treat thermoplastic waste, then the waste can be processed, but energy consumption is high and the process is difficult to adapt for large-scale use
Solution Approach 1:
The invention changes the temperature parameter from high-temperature pyrolysis (>400°C) to low-temperature depolymerization (50-150°C), fundamentally altering the energy input requirements while maintaining waste processing capability
Solution Approach 2:
The invention replaces the thermal field (heat-based pyrolysis) with a chemical field approach using catalysts and solvents to achieve depolymerization at low temperatures, substituting thermal energy with chemical catalysis
2Productivity
If a bed of molten lead is used for recycling polymethyl methacrylate, then the resin can be decomposed, but the bed of lead becomes fouled with contaminants and solid residues
Solution Approach 1:
The invention extracts and removes the problematic molten lead medium from the recycling process, replacing it with an aqueous alkaline solution that does not accumulate contaminants and can be easily separated from decomposition products
Solution Approach 2:
The invention changes the physical state parameter from molten metal (lead at >400°C) to aqueous solution at low temperature (50-150°C), eliminating the fouling issue inherent in using molten metal beds
3Productivity
If thermal pyrolysis or molten lead bed is used, then depolymerization can occur, but the processing time is long and energy consumption is high
Solution Approach 1:
The invention changes the temperature parameter from high-temperature processing (>400°C) to low-temperature processing (50-150°C), enabling faster reaction kinetics through catalytic pathways while reducing thermal inertia and heating time
Solution Approach 2:
The invention employs periodic addition of base solution and catalyst to maintain optimal pH and catalytic activity throughout the depolymerization process, ensuring continuous efficient reaction without long idle periods
4Quantity of substance
If conventional depolymerization methods are used, then monomers can be recovered, but the yield and quality of reusable monomers are unsatisfactory
Solution Approach 1:
The invention implements feedback control through pH monitoring and adjustment during depolymerization, maintaining optimal alkaline conditions to maximize monomer recovery yield and purity while preventing side reactions that would degrade monomer quality
Solution Approach 2:
The invention introduces an aqueous alkaline solution as an intermediary medium that facilitates clean depolymerization reactions, acting as both solvent and catalyst to produce high-purity monomers while the base metal catalyst accelerates the reaction without contaminating the product
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
This approach enables efficient depolymerization with reduced energy use, preserving material quality and increasing the yield and quality of reusable monomers, making it suitable for recycling thermoplastic resins and composite materials.
Implementation Method 1
using techniques such as pulsed electric fields or microwaves
Implementation Method 2
using techniques such as pulsed electric fields or microwaves
Implementation Method 3
heating said resin in order to convert, at least in part, the thermoplastic polymer P1 into at least two polymers P2
Implementation Method 4
cooling said at least two polymers P2 obtained after heating to a temperature substantially equal to or lower than the boiling point of said base monomers
Implementation Method 5
dissolving said at least two polymers P2 in a solution comprising said base monomers
Data Source
AI summary
The present invention relates to a process for the recycling of an article comprising a thermoplastic polymer P1 resin, said thermoplastic polymer P1 having been formed from base monomers, said process comprising the following stages:heating said resin in order to convert, at least in part, the thermoplastic polymer P1 into at least two polymers P2, said at least two polymers P2 having a lower molar mass than the molar mass of said polymer P1, cooling said at least two polymers P2 obtained after heating to a temperature substantially equal to or lower than the boiling point of said base monomers, anddissolving said at least two polymers P2 in a solution comprising said base monomers.