Given that management of end-of-life tyres (ELTs) can have a major impact on the environment, more than 176,000 tonnes of ELTs are collected in Spain each year according to data from the SIGNUS collection system. Dumping large quantities of ELTs in landfills creates a focus of colonies of insects and rodents, as well as a hazard of fire that generates billowing smoke and causes situations of environmental and health alarms in neighbouring towns.
With the aim of recovering this waste to create new high-quality materials for application in the construction industry, AIMPLAS, the Plastics Technology Centre, is working on the RECICAUTXU Project, which focuses on developing industrial processes to obtain a new generation of composite materials loaded with devulcanized rubber particles from ELTs and even other kinds of cross-linked materials. These materials have applications in the construction industry as products such as more sustainable films, sheets and profiles with improved properties.
The different treatment systems currently available for this waste (e.g. thermal decomposition, pyrolysis, incineration, and shredding) have different problems that make them unsustainable. Processes and solutions have therefore been proposed in recent years to mix the shredded rubber from these tyres with other materials such as plastic with the aim of reusing this rubber as a secondary material in new industrial products while promoting the principles of the circular economy.
However, many improvements must still be made to these technologies, given that the properties of the materials obtained to date do not meet the necessary quality standards.
The RECICAUTXU Project is funded by the Valencian Innovation Agency (AVI). AIMPLAS collaborates on the project with the Department of Transport Engineering and Infrastructure of the Universitat Politècnica de València (UPV). The project proposes including devulcanized rubber particles in thermoplastic polyolefin matrices to obtain extruded elastomeric products with good elastic properties and impact resistance for use in construction elements, transport infrastructure, building interiors, sports facilities, playgrounds, signage, and road safety systems.
In the words of Vicent Martínez, a researcher in the Mechanical Recycling Area and head of the project at AIMPLAS, “There are currently very few applications for rubber waste, which makes it necessary to broaden the range of transformation processes for this recycled material and find new products of greater added value. In this project, we’re trying to improve recovery of this waste through innovative processes that help obtain more sustainable materials in a circular economy”.
The development of devulcanization technologies for ELT rubber could also be applied to other kinds of cross-linked materials, such as polyurethane foams, cross-linked polyethylene tubing and cable sheathing, thus providing a more sustainable alternative for management and recovery of these kinds of materials and expanding the field of application to new market sectors.