Polyurethane Recycling Solvent Removal via Aminolysis Separation
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Solution Overview
Problem
Existing recycling processes for polyurethanes, polyurethane ureas, and polyisocyanurates face challenges in separating polyols from isocyanate derivatives, leading to limited applicability and potential contamination, especially in polyurethane waste.
Innovation Solution
A solvent-efficient process involving aminolysis reaction with primary amines, followed by evaporation and solid-liquid separation, allows for the decomposition of these polymers into monomers, reducing solvent consumption and costs.
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 it easily fails due to contamination in polyurethane waste and has limited applicability
Solution Approach 1:
The patent changes the chemical parameters of the system by introducing a water-soluble organic amine that reacts with isocyanate groups to form water-soluble urea derivatives. This chemical transformation enables reliable separation of polyols from isocyanate-containing compounds through water solubility differences, overcoming the limitations of phase decay separation and expanding applicability to contaminated polyurethane waste.
Solution Approach 2:
The patent uses water-soluble organic amines as intermediary substances that mediate the separation process. These amines react with isocyanate groups to form water-soluble urea derivatives, acting as a bridge that enables separation through solubility differences. This intermediary approach allows reliable separation across various polyurethane compositions and contamination levels.
2Productivity
If conventional recycling processes are used, then polyurethanes can be decomposed into monomers, but solvent consumption is high leading to increased costs and CO2 footprint
Solution Approach 1:
The patent employs water as the primary solvent, which is abundant, inexpensive, and environmentally benign. The water-soluble organic amine enables the decomposition and separation processes to proceed efficiently using water instead of organic solvents, making the system self-sufficient in terms of solvent provision and eliminating the need for costly solvent recovery and disposal operations.
Solution Approach 2:
The patent changes the solvent system from organic solvents to water-based systems by utilizing water-soluble organic amines. This parameter change fundamentally alters the process economics and environmental impact, reducing solvent consumption and elimination the need for complex solvent recovery infrastructure while maintaining high recycling efficiency.
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, polyurethane ureas, and polyisocyanurates, minimizing solvent use and CO2 footprint, enabling their reuse in various applications.
Implementation Method 1
subjecting the mixture obtained according to (i.2) in RA to aminolysis reaction conditions, obtaining a mixture M comprising one or more polyurea-containing compounds, and further comprising one or more polyols and one or more primary amines
Implementation Method 2
passing a second solvent S and the mixture M obtained according to (i) into an evaporation unit EU, obtaining, from the evaporation unit EU, a vapor mixture MV comprising S and at least a portion of the one or more primary amines
Implementation Method 3
separating the one or more primary amines from MV obtained according to (ii) in a purification unit PU, obtaining a vapor mixture A comprising the one or more primary amines depleted in S
Data Source
AI summary
The present invention relates to a solvent-efficient 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.