Polyurethane Cleaving via Alcoholysis and Phase Separation
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Solution Overview
Problem
Current chemical recycling methods for polyurethane products face challenges in achieving high purity recovery of polyols and amines, as well as efficiently isolating carbamates, which are valuable intermediates.
Innovation Solution
A process involving the reaction of polyurethane products with a monofunctional araliphatic alcohol in the presence of an alcoholysis catalyst, followed by separation of the resulting carbamate from the liquid polyol phase, allowing for the recovery of raw materials such as polyols and isocyanates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional chemical recycling methods are used to recover polyols and amines, then raw materials can be recovered, but the purity of recovered polyols and amines is insufficient and carbamates cannot be efficiently isolated
Solution Approach 1:
The invention segments the recycling process into distinct phases: alcoholysis reaction phase, solid-liquid separation phase, and purification phase. By separating carbamates as a distinct solid phase from the liquid polyol phase, the process achieves both high purity recovery of polyols and efficient isolation of carbamates, resolving the contradiction between manufacturing precision and productivity
Solution Approach 2:
The invention extracts carbamates from the reaction mixture as a separate solid phase through filtration or centrifugation. This extraction step isolates carbamates before they can contaminate the polyol recovery stream, enabling simultaneous high-purity recovery of both polyols and carbamates, thereby resolving the contradiction between purity and isolation efficiency
2Use of energy by moving object
If polyurethane products are incinerated, then energy can be recovered, but raw material loops cannot be closed
Solution Approach 1:
The invention changes the fundamental parameter of waste treatment from thermal destruction (incineration) to chemical transformation (alcoholysis). By using monofunctional araliphatic alcohols to cleave urethane bonds under controlled conditions, the process converts waste polyurethane into valuable recoverable materials (polyols and carbamates) rather than merely recovering energy, thus eliminating loss of substance while maintaining energy efficiency
Solution Approach 2:
The invention implements a comprehensive recovery system that captures both polyols and carbamates from the alcoholysis reaction. Instead of discarding polyurethane waste or merely incinerating it for energy, the process recovers raw materials in high purity, closing the material loop and enabling sustainable polyurethane production
3Productivity
If physical recycling is used, then polyurethane waste can be reused, but the limits of mechanical comminution are reached
Solution Approach 1:
The invention changes the recycling approach from physical mechanical comminution to chemical transformation. By using alcoholysis to break down polyurethane at the molecular level and recover pure polyols and carbamates, the process overcomes the quality degradation limits inherent in mechanical recycling, enabling unlimited recycling cycles with consistent material quality
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 process enables the efficient separation and recovery of high-purity carbamates, polyols, and isocyanates, facilitating their reuse in polyurethane production and addressing the limitations of existing chemical recycling methods.
Implementation Method 1
reacting the polyurethane product with a monofunctional araliphatic alcohol in the presence of an alcoholysis catalyst to obtain a product mixture containing (i) a liquid polyol phase and (ii) a solid carbamate
Implementation Method 2
separating the carbamate from the product mixture, leaving behind the liquid polyol phase
Data Source
AI summary
The invention relates to a method for cleaving polyurethane products, having the steps of (A) providing a polyurethane product which is based on isocyanate components and a polyol component; (B) reacting the polyurethane product with a monofunctional araliphatic alcohol in the presence of an alcoholysis catalyst, thereby obtaining a product mixture containing a liquid polyol phase and a solid carbamate of an isocyanate of the isocyanate component and the monofunctional araliphatic alcohol; and (C) separating the carbamate from the product mixture, thereby leaving the liquid polyol phase.