Polyurethane Recycling via Aminolysis for Contaminated Waste Separation
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Solution Overview
Problem
Existing recycling processes for polyurethanes, polyurethane ureas, and polyisocyanurates are limited by the difficulty in separating polyols from isocyanate derivatives, particularly when the waste is contaminated, leading to restricted applicability.
Innovation Solution
A process involving aminolysis and cleavage reactions to decompose these polymers into monomers, using primary amines in a reactor, followed by isolation and purification steps to obtain polyurea-containing compounds and polyols, which are then converted into polyamines or polyisocyanates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If phase decay separation is used to separate polyols from isocyanate derivatives, then separation can be achieved for selected polyurethanes, but the process fails due to contamination in polyurethane waste, severely limiting applicability
Solution Approach 1:
The patent changes the separation parameter from physical phase decay to chemical selectivity. By using a chemical process that selectively reacts with isocyanate groups to form insoluble polyurea derivatives, the method achieves reliable separation based on chemical parameter changes rather than physical phase behavior, enabling it to handle contaminated waste streams
Solution Approach 2:
The patent introduces an intermediary substance (the amine reagent that forms the polyurea derivative) to enable separation. This intermediary chemically interacts with the isocyanate groups in polyurethane, creating a new phase that can be separated from the polyol, thus solving the separation problem that phase decay alone cannot address
2Productivity
If conventional recycling processes are used, then polyurethanes can be decomposed, but the separation of polyols from isocyanate derivatives remains difficult and limited
Solution Approach 1:
The patent changes the chemical parameters of the decomposition process by using aminolysis to form polyurea derivatives with different solubility characteristics. This parameter change enables simpler separation compared to conventional methods, as the polyurea derivative precipitates out while polyol remains in solution, reducing the complexity of the separation process
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 process effectively recycles a variety of polyurethanes, reducing the CO2 footprint by producing new polymers from waste materials, suitable for various industrial applications.
Implementation Method 1
subjecting the mixture obtained according to (ii) in RA to aminolysis reaction conditions, obtaining a mixture M comprising one or more polyurea-containing compounds, and further comprising one or more polyols
Implementation Method 2
subjecting the mixture U comprising the one or more polyurea-containing compounds obtained according to (iv) to cleavage reaction conditions in a reactor unit Rc, obtaining either one or more corresponding polyamines or one or more corresponding polyisocyanates
Data Source
AI summary
The present invention relates to a process for recycling one or more polymers selected from the group consisting of polyurethanes, polyurethane ureas, polyisocyanurates, and a mixture of two or more thereof, said one or more polymers being contained in a solid material W.