Polyurethane Waste Polyol Recovery Using Cyclic Carbonate Treatment
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Solution Overview
Problem
Existing methods for recovering polyol from polyurethane waste face issues such as gel formation due to the high reactivity of isocyanate with amine compounds, leading to incomplete reactions and reduced mechanical strength of the resulting resin, and unreacted treatment agents cannot be effectively removed, affecting the purity and quality of the recycled resin.
Innovation Solution
A method involving the use of a treatment agent represented by Formula (I) to react with the amine compound in the degradation product, followed by distillation to remove unreacted portions, ensuring the reaction product remains in a liquid form and allowing for high-purity polyol recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If acid anhydride is used as treatment agent to react with amine compound, then the amine compound can be removed, but precipitates are produced and unreacted treatment agent cannot be removed by distillation
Solution Approach 1:
The patent changes the chemical structure parameters of the treatment agent by introducing cyclic carbonate esters with specific ring structures (ethylene carbonate, propylene carbonate, butylene carbonate). This structural modification enables the treatment agent to react with amine compounds to form soluble carbamate products rather than precipitates, while also allowing easy removal of unreacted treatment agent through distillation due to the cyclic carbonate ester's volatility.
2Reliability
If acid is used as treatment agent to react with amine compound, then the amine compound can be removed, but water is produced that must be removed causing time-consuming process
Solution Approach 1:
The patent converts the harmful effect of water production in acid-amine reactions into a beneficial approach by using cyclic carbonate esters as treatment agents. The reaction between cyclic carbonate esters and amine compounds produces carbamate products without generating water, thereby eliminating the need for time-consuming drying processes while effectively removing amine compounds from the polyol mixture.
3Reliability
If large amount of treatment agent is used to ensure complete reaction with amine compound, then amine removal is effective, but mechanical strength of recycled resin decreases
Solution Approach 1:
The patent optimizes the chemical parameters of the treatment agent by selecting cyclic carbonate esters with specific molecular structures and reactivity characteristics. These agents exhibit high selectivity and reactivity toward amine compounds, enabling complete amine removal with minimal excess treatment agent. The controlled reaction parameters and specific chemical structure of cyclic carbonate esters prevent mechanical strength degradation while ensuring thorough amine compound removal.
4Reliability
If conventional treatment agents are used to remove amine compound, then amine can be removed, but unreacted treatment agent cannot be effectively removed by distillation
Solution Approach 1:
The patent modifies the physical and chemical parameters of the treatment agent by using cyclic carbonate esters (ethylene carbonate, propylene carbonate, butylene carbonate) which possess specific volatility characteristics. These parameters enable the unreacted treatment agent to be easily separated from the polyol mixture through distillation, achieving high-purity polyol recovery while maintaining effective amine compound removal.
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 method prevents gel formation and enables the removal of unreacted treatment agents, resulting in a high-purity polyol mixture suitable for subsequent applications without the need for additional filtration steps.
Implementation Method 1
subjecting the degradation product and a treatment agent represented by Formula (I) to a reaction to obtain a reaction solution including a reaction product and the polyol compound, the reaction product being formed by reacting the amine compound in the degradation product with the treatment agent
Implementation Method 2
subjecting the reaction solution to distillation to remove an unreacted portion of treatment agent, thereby obtaining a polyol mixture including the reaction product and the polyol compound
Data Source
AI summary
A method for recovering polyol from a polyurethane waste includes: subjecting the polyurethane waste to degradation using a degradation agent, and then removing the degradation agent to obtain a degradation product including an amine compound and a polyol compound; subjecting the degradation product and a treatment agent represented by Formula (I) to a reaction to obtain a reaction solution including a reaction product and the polyol compound, the reaction product being formed by reacting the amine compound in the degradation product with the treatment agent, the reaction product being in a liquid form at 20° C. to 40° C.; and subjecting the reaction solution to distillation to remove an unreacted portion of the treatment agent, thereby obtaining a polyol mixture including the reaction product and the polyol compound, wherein each of the substituents in Formula (I) is given the definitions as set forth in the Specification and Claims.