Continuous Recycling of Solid Polyurethane Articles into Liquid Pre-Polymers
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Solution Overview
Problem
Existing methods for recycling polyurethane articles, particularly those using toluene diisocyanate, face challenges such as large volume handling, low density, and limited scalability due to batch processing limitations, leading to inefficient and costly chemical recycling processes.
Innovation Solution
A continuous process is developed where pre-formed polyurethane articles are pre-heated and mixed with a toluene diisocyanate composition at controlled temperatures (130-165°C) to produce isocyanate-functional liquid pre-polymers, optimizing reaction efficiency and scalability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If batch processing is used to recycle polyurethane articles with toluene diisocyanate, then the process can handle the material, but the large volume and low density of the articles make scaling up difficult and the process time-consuming
Solution Approach 1:
The patent transitions from batch processing to continuous processing, where polyurethane articles are continuously fed into a reactor with toluene diisocyanate and processed through a heating zone. This continuous operation eliminates the start-stop nature of batch processing, enabling consistent throughput and reducing overall process time while maintaining effective recycling of the polyurethane material.
2Reliability
If large volumes of toluene diisocyanate are used to process polyurethane articles, then the recycling can be effective, but the cost and environmental burden increase
Solution Approach 1:
The patent optimizes the temperature parameter in the heating zone (maintaining temperatures between 100-200°C) to enhance the reaction efficiency between toluene diisocyanate and polyurethane articles. This temperature optimization allows for more effective recycling with reduced material consumption, as the reaction proceeds more efficiently at controlled elevated temperatures compared to ambient conditions.
3Ease of manufacture
If chemical recycling processes are used to break down polyurethane articles, then the material can be recovered, but the processes are time-consuming and cost-prohibitive
Solution Approach 1:
The patent replaces complex multi-step chemical recycling processes with a simpler one-step reaction system using toluene diisocyanate. Instead of employing multiple chemical treatments and separation steps, the invention uses a single reactive component that directly converts polyurethane articles into soluble pre-polymers, significantly simplifying the manufacturing process and improving productivity.
4Object-affected harmful factors
If pre-formed polyurethane articles are disposed of in landfills, then the environmental burden is minimized, but the resource waste increases
Solution Approach 1:
The patent implements a recovery process where polyurethane articles are chemically converted back into soluble pre-polymers that can be reused. Instead of discarding the material in landfills, the system recovers the polyurethane content through reaction with toluene diisocyanate, transforming waste material into valuable reusable product and eliminating the need for landfill disposal.
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 method allows for the efficient conversion of polyurethane articles into liquid pre-polymers, reducing the need for large volumes of toluene diisocyanate and enabling continuous production, thereby addressing scalability and cost issues in recycling.
Implementation Method 1
contacting the processed and/or densified pre-formed polyurethane article with the toluene diisocyanate composition, thereby producing a polyurethane pre-polymer
Implementation Method 2
pre-heating a toluene diisocyanate composition at a temperature ranging from about 130 to 165° C.
Data Source
AI summary
Provided herein are methods for the continuous production of liquid polyurethane pre-polymer from pre-formed solid polyurethane articles with toluene diisocyanate composition under defined conditions. The methods include methods of producing polyurethane pre-polymers. methods of recycling pre-formed polyurethane articles. and methods of converting solid polyurethane articles into a liquid polyurethane material.