A week in which Europeans are encouraged to raise awareness about the sustainable management of waste so that they do not become causes of water, soil or air pollution. A type of management that is closely linked to another no less important objective such as the management, also sustainable, of resources aimed at reducing the extraction and consumption of new raw materials for the manufacture of new ones, many of them made with the same raw materials as those that are discarded. The result is the circular economy.
Well, like other productive sectors, the tire industry is intensively applied to both objectives. And, as the name of the week itself indicates, prevention is an important factor both to reduce the volumes of out-of-use tires and to take advantage of the raw materials with which they are made.
Signus, as the entity that organizes the management of end-of-life tires, works in both directions. On the prevention side, Román Martín, director of Institutional Relations at Signus, explains that “we work with the manufacturers attached to Signus, who are obliged to implement prevention plans for the generation of waste, with the measures that we have identified to extend the useful life of the tires and to facilitate their reuse, recycling and recovery formulas, which are based on eco-design. And they decide which ones, adapt and implement them in the development and manufacturing processes of their tires.”
Ecodesign, a tool for preventing waste from out-of-use tires
Indeed, tire waste prevention covers their entire life cycle, from manufacturing to recycling or reuse. On the part of the manufacturers, they “have been working for years on waste minimization from the three areas, manufacturing, use and recycling,” says José Luis Rodríguez, director of Afane, (Association of Tire Manufacturers), an organization that brings together five major brands. As a product included in the European Ecodesign Regulation for Sustainable Products (ESPR), “the sector has obligations that range from the design itself, which includes a series of conditions to improve the sustainability of the product, also in terms of waste prevention.”
The eco-design of tires to advance these objectives must take into account everything from the emissions of the process, including the obtaining of materials, to the preparation for better recyclability once their useful life has ended. “A particular characteristic in the case of tires is that they must maintain their safety, performance, durability and other performance parameters, and, at the same time, reduce as much as possible the consumption of raw materials that depend on oil, for example. You cannot change one parameter and that’s it, because it is very difficult to change one thing without affecting the others,” Rodríguez emphasizes.
In any case, in the manufacturing phase the sector is “working to incorporate recycled materials in this process, such as waste from the rubber mixtures with which they are manufactured, or those that are discarded due to some manufacturing fault. In fact, it already reuses part of the waste, for example, those that are discarded because they have a manufacturing fault, etc.
One of the great current challenges of the sector is “to reduce the microparticles that are released due to the friction of the tire with the asphalt.” And, also, “focused on tires from the industrial field, trucks, or even airplanes, which can be retreaded, which also lengthens the useful life. It must be taken into account, Rodríguez points out, that some of them are huge tires, up to two meters in diameter, which require a lot of material for their manufacture. Therefore, making them more durable by retreading them or restructuring the tread is very interesting. Thus, a truck tire can last up to three times as long and “One airplane would be retreaded about 10 times.”
When the end is the beginning
When the tires have rolled as much as they have to and there is no way for them to go any further, that is when Signus comes into action. “We are facilitators of the recycling process, of raw materials so that the treatment plants have tires from which to extract the elements that compose them: rubber, metal materials and textile materials.
Another mission of Signus is “to ensure that all these raw materials have more applicability, that they are more easily extractable and, of course, search and find applications for them.” In short, it means that an out-of-use tire is not the same as waste.
To achieve this, Signus “works and seeks synergies with universities, technology centers or private companies that develop projects to use these secondary raw materials with high added value,” explains Román Martín. From the Innovation and Development department of Signus, “based on a lot of R&D, impulse and collaboration with those entities that I said, we endorse and promote the use of rubber powder for applications in bituminous mixtures for asphalt, in bases for artificial grass, floors for sports fields and playgrounds, urban furniture and even components of building materials, among others.”
With metallic materials, “the exit is not very complicated, because they are absorbed by the steel industry,” says Román Martín. In the case of the textile fraction, Signus and the GAIKER Technology Center, a member of the Busque Research & Technology Alliance, led the SIGNUS FIBER2FIBER project to advance the chemical recycling of the textile fibers contained in the tire. “Thanks to this project, it has been possible to recover polyester from the textile fraction of tires, a difficult process, to make its recycling possible and, therefore, its reincorporation into the value chain,” says Martín.
Precisely, this route “of chemical recycling of end-of-use tires is what we are now trying to give an important boost to, mainly to the pyrolysis processes that we want to develop further.”
