Turpentine Devulcanization of Vulcanized Rubber
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Solution Overview
Problem
Current devulcanization processes for rubber are costly, difficult to scale, and inefficient, often requiring high pressures, temperatures, toxic reagents, and lengthy processes, which limits the recovery and recycling of used tires and rubber products.
Innovation Solution
The use of turpentine-based devulcanization methods, involving turpentine liquids such as natural turpentine, synthetic turpentine, and α-terpineol, which contact vulcanized rubber at moderate temperatures and pressures, breaking sulfur-sulfur bonds without the need for high-pressure vessels, microwaves, or toxic catalysts, allowing for efficient devulcanization and reprocessing of rubber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional devulcanization processes are used, then rubber can be devulcanized, but the process becomes excessively expensive to construct and operate
Solution Approach 1:
The patent changes the operational parameters by conducting devulcanization at atmospheric pressure and moderate temperatures (below 300°C) rather than high pressure and high temperature, fundamentally altering the process conditions to reduce energy consumption and equipment requirements while maintaining effective devulcanization
Solution Approach 2:
The patent employs simple, inexpensive equipment such as batch reactors and conventional mixers instead of expensive high-pressure vessels and complex mechanical devices, reducing capital investment and operational costs while achieving the same devulcanization objective
2Reliability
If conventional devulcanization processes are used, then rubber can be devulcanized, but the process is exceedingly difficult to scale up and control
Solution Approach 1:
The patent employs batch processing where rubber is treated in separate containers rather than continuous processing, allowing for easier control and scaling by simply repeating the batch operation with different quantities of rubber, thereby simplifying process control and equipment requirements
Solution Approach 2:
The devulcanization process uses the rubber itself as the reaction medium by immersing it in devulcanization agents, eliminating the need for complex external equipment and control systems, and enabling straightforward scaling by adjusting the amount of rubber and agent used in each batch
3Manufacturing precision
If conventional devulcanization processes are used, then rubber can be devulcanized, but the process is cumbersome to recover and purify the high-quality devulcanized rubber
Solution Approach 1:
The patent extracts the devulcanized rubber from the reaction mixture by filtration or decantation after the devulcanization agent has performed its function, separating the high-quality devulcanized rubber from the spent agent and allowing for straightforward purification without complex equipment
Solution Approach 2:
The patent maintains moderate processing conditions that preserve rubber quality while enabling easy separation, avoiding the need for complex purification equipment by keeping the devulcanized rubber in a form that can be readily separated from the reaction medium through simple filtration or settling operations
4Reliability
If conventional devulcanization processes are used, then rubber can be devulcanized, but the process requires operating at an inordinately elevated pressure
Solution Approach 1:
The patent fundamentally changes the pressure parameter from high pressure operation to atmospheric pressure operation, eliminating the need for high-pressure vessels and complex pressure control systems while maintaining effective devulcanization through alternative mechanisms such as chemical agents and moderate temperature treatment
5Reliability
If conventional devulcanization processes are used, then rubber can be devulcanized, but the process requires operating at a very high temperature
Solution Approach 1:
The patent changes the temperature parameter from very high temperature to moderate temperature operation (below 300°C), reducing energy consumption and avoiding thermal degradation of rubber while maintaining effective devulcanization through enhanced chemical mechanisms and catalysts
6Reliability
If conventional devulcanization processes are used, then rubber can be devulcanized, but the process requires using expensive vessels and mechanical devices
Solution Approach 1:
The patent replaces expensive high-pressure vessels, extruders, and high-speed rollers with simple, inexpensive equipment such as batch reactors, conventional mixers, and filtration systems, dramatically reducing capital investment and operational costs while achieving the same devulcanization objective
Solution Approach 2:
The patent substitutes complex mechanical systems for chemical and thermal mechanisms, using devulcanization agents and moderate temperature treatment instead of high-shear mechanical devices, thereby eliminating the need for expensive mechanical equipment while maintaining effective devulcanization
7Reliability
If conventional devulcanization processes are used, then rubber can be devulcanized, but the process requires supplying a special form of energy
Solution Approach 1:
The patent changes the energy form from specialized energy sources (ultrasonic, microwave) to conventional thermal energy and chemical reactions, using moderate temperature heating and devulcanization agents instead of complex energy delivery systems, thereby simplifying the energy supply requirements and reducing equipment costs
8Reliability
If conventional devulcanization processes are used, then rubber can be devulcanized, but the process requires an unusually long time
Solution Approach 1:
The patent changes the temporal parameter by using more reactive devulcanization agents and optimized conditions that accelerate the devulcanization reaction, reducing the processing time from unusually long durations to more acceptable batch processing times while maintaining effective devulcanization
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 enables the devulcanization of rubber under mild conditions, preserving the original microstructure and molecular weight, making it suitable for recompounding and recuring into high-quality rubber products, with reduced costs and environmental impact.
Implementation Method 1
contacting a vulcanized rubber with a turpentine liquid in a reaction mixture... breaking sulfur-sulfur bonds
Data Source
AI summary
Vulcanized rubber is devulcanized by contacting the vulcanized rubber with a terpentine liquid in a reaction mixture in the absence of an alkali metal.