Polyurethane Foam Degassing for Chemolysis Purity
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Solution Overview
Problem
Current chemical recycling methods for polyurethane foams face challenges in removing volatile accompanying substances like oxygen, blowing agents, and disinfectants from the foam's cell structure, which can disrupt the recycling process and result in impurities and oxidation reactions, limiting the purity and quality of recovered raw materials.
Innovation Solution
A method involving the degassing of polyurethane foam to remove volatile substances such as oxygen, blowing agents, and disinfectants at pressures up to 960 mbar and temperatures up to 120°C before chemolysis, using a chemolysis apparatus with a gas removal device, ensuring the foam is degassed and processed in an inert gas atmosphere to prevent oxidation and contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyurethane foam is subjected to chemolysis without prior degassing, then the recycling process can proceed continuously, but volatile substances like oxygen and blowing agents remain in the foam causing oxidation reactions and impurities in recovered raw materials
Solution Approach 1:
The patent applies preliminary degassing action by removing volatile substances (oxygen, blowing agents, disinfectants) from the polyurethane foam before chemolysis treatment. This preliminary removal prevents oxidation reactions during chemolysis and ensures high purity of recovered polyols and amines, resolving the contradiction between material purity and process continuity
Solution Approach 2:
The patent creates an inert atmosphere by replacing volatile substances with inert gas (nitrogen or carbon dioxide) during the degassing step. This inert environment prevents oxidation reactions during subsequent chemolysis while maintaining process efficiency, as the inert gas does not interfere with the chemical recycling reactions
2Quantity of substance
If high pressure is applied to remove volatile substances from foam cell structure, then removal efficiency increases, but energy consumption and equipment complexity increase
Solution Approach 1:
The patent changes physical parameters (temperature and pressure) during the degassing process to optimize volatile substance removal. By controlling temperature between -20°C to 120°C and pressure from 0.1 to 960 mbar, the process efficiently removes volatiles without requiring excessive energy input or complex equipment
Solution Approach 2:
The patent employs periodic action through repeated cycles of pressure reduction and restoration during degassing. This cyclic process enhances the removal of volatile substances from the foam cell structure by creating pressure differentials that drive volatiles out, while maintaining reasonable energy consumption through controlled cycling rather than continuous high-pressure operation
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 effectively removes volatile substances, minimizing oxidation reactions and ensuring the recovery of high-purity polyols and amines, thereby enhancing the quality and purity of recycled materials for reuse in new polyurethane products.
Implementation Method 1
removing at least oxygen, but preferably all constituents of component X or any gaseous decomposition products thereof that may have formed, from the chemolysis apparatus at a pressure of not more than 960 mbar(abs.) and a temperature of not more than 120° C. in gaseous form via a gas removal device
Implementation Method 2
the chemolysis of the polyurethane foam with a chemolysis reagent, wherein the polyurethane foam is degassed before being contacted with the chemolysis reagent
Data Source
AI summary
The present invention relates to a process for recovering raw materials from a polyurethane foam, comprising step (A), the providing of a polyurethane foam based on an isocyanate component and a polyol component, wherein the polyurethane foam comprises a cell structure containing one or more volatile accompanying substances, namely a component X selected from the group consisting of oxygen, a blowing agent, a disinfectant and a mixture of two or more of the above, wherein component X comprises at least oxygen, step (B), the chemolysis of the polyurethane foam with a chemolysis reagent, wherein the polyurethane foam is degassed before being contacted with the chemolysis reagent, wherein at least oxygen, but preferably all constituents of component X or any gaseous breakdown products thereof that have formed are removed from the chemolysis apparatus in gaseous form via a gas removal device at a pressure of not more than 960 mbar(abs.) and a temperature of not more than 120° C., so as to obtain a degassed polyurethane foam, followed by the reaction of the degassed polyurethane foam with the chemolysis reagent in the presence of a catalyst in an inert gas atmosphere and the workup of the product mixture obtained by the chemolysis, step (C), the obtaining of at least one polyol, and optionally step (D), the obtaining of at least one amine corresponding to an isocyanate of the isocyanate component.