Polyurethane Foam Dispersion Pretreatment for Low-Temperature Solvolysis
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Solution Overview
Problem
Existing polyurethane recycling methods are inefficient, complex, and expensive due to high reaction temperatures and times, low polyol quality, and difficulties in feeding and dosing polyurethane waste into reactors, leading to incomplete conversion and low productivity.
Innovation Solution
A process involving the preparation of a polyurethane dispersion with a controlled particle size and concentration, followed by solvolysis, which allows for precise dosing, efficient mixing, and continuous operation, reducing reaction times and improving polyol yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high reaction temperature (230-250°C) and long reaction time (6-12 hours) are used for acidolysis of polyurethane, then polyol yield is improved, but energy consumption and production cost increase significantly
Solution Approach 1:
The invention changes the reaction parameters by using a different chemical pathway (solvolysis with specific catalysts) that operates at lower temperatures (80-120°C) while maintaining high polyol yield. This transforms the reaction conditions from high-energy to low-energy operation without sacrificing product quantity.
Solution Approach 2:
The invention replaces the thermal energy input mechanism with a catalytic mechanism. Instead of relying on high temperature to drive the reaction, a catalyst is used to lower the activation energy, enabling the reaction to proceed efficiently at lower temperatures and thus reducing energy consumption.
2Quantity of substance
If high reaction temperature (230-250°C) and long reaction time (6-12 hours) are used for acidolysis of polyurethane, then polyol yield is improved, but production time and productivity deteriorate
Solution Approach 1:
The invention changes the reaction parameters by using a different chemical pathway (solvolysis with specific catalysts) that operates at lower temperatures (80-120°C) while maintaining high polyol yield. This transforms the reaction conditions from high-energy to low-energy operation without sacrificing product quantity.
Solution Approach 2:
The invention replaces the thermal energy input mechanism with a catalytic mechanism. Instead of relying on high temperature to drive the reaction, a catalyst is used to lower the activation energy, enabling the reaction to proceed efficiently at lower temperatures and thus reducing energy consumption.
3Ease of operation
If polyurethane is fed as crushed particles (1-20 mm) into the reactor, then feeding is simplified, but mixing efficiency and reaction completeness deteriorate
Solution Approach 1:
The invention segments the polyurethane into fine particles (0.1-2.0 mm) rather than using crushed particles (1-20 mm). This finer segmentation increases the surface area to volume ratio, improving contact between the polyurethane and the solvolysis reagents, which enhances reaction completeness while maintaining ease of feeding through the fine particle size.
Solution Approach 2:
The invention applies local quality by creating a specific particle size distribution (0.1-2.0 mm) that optimizes both feeding properties and reaction characteristics. The fine particles ensure thorough mixing and complete reaction, while the size range maintains good flow and feeding characteristics.
4Quantity of substance
If multiple process steps and reactants are used for polyurethane recycling, then polyol quality is improved, but process complexity and cost increase
Solution Approach 1:
The invention extracts and eliminates unnecessary process steps and reactants from the recycling process. By using a single solvolysis step with a specific catalyst system, the process achieves high polyol quality without requiring multiple sequential reactions or complex purification steps, thus simplifying the overall process while maintaining product quality.
Solution Approach 2:
The invention applies universality by using a catalyst system that performs multiple functions simultaneously: it accelerates the solvolysis reaction, enables complete conversion of polyurethane, and produces high-quality polyol in a single process step, eliminating the need for separate treatment steps.
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 achieves high polyol yields and quality, enabling large-scale recycling with reduced reaction times and costs, and allows for the production of high-quality polyurethane foams using recycled polyols.
Implementation Method 1
The present invention provides a new method for recycling of polyurethane, in particular polyurethane foam, via solvolysis.
Implementation Method 2
Hydrolysis was also tested for depolymerization of polyurethanes in the prior art.
Data Source
Figure 1a~1b
Figure 2a~2b
Figure 3
AI summary
The present invention provides a new method for recycling of polyurethane, in particular polyurethane foam via solvolysis. The new method includes a very efficient pre-treatment method of the polyurethane, wherein it is converted into a polyurethane dispersion.