A tyre's life cycle and recycling
We use “life cycle” to refer to the different stages that a product undergoes from manufacture to use and, ultimately, recycling. The life cycle of a tyre begins with a rubber tree in the southern hemisphere, for example in Indonesia or Thailand. Then, the following stages of life cycle includ the manufacture of raw materials and products, storage and several rounds of transportation. The tyre’s actual life cycle ends, for instance, when the tyre is crushed and used as a construction material.
The life cycle can be roughly divided into four parts:
- Purchasing and manufacture of production inputs, such as raw materials and energy.
- Tyre manufacture.
- Use of tyre.
- Utilisation of used tyres.
The outset of our environmental protection is the life cycle approach. This means that we take responsibility for the environmental impacts of our activities and products throughout their life cycle. In accordance with our purchasing policy, our product procurement process includes determining our suppliers’ commitment to the environmental aspects. In 2017, 71% of our raw material suppliers had the ISO 14001 certification. We require all of our contract partners, including suppliers and contractors, to commit to our principles.
Most of the environmental impacts during a tyre’s life cycle are generated during its use. The single most important factor is the vehicle’s fuel consumption. Fuel consumption can be decreased by reducing the tyre’s weight and rolling resistance, thereby cutting the exhaust gas emissions and the formation of greenhouse gases. However, the most significant factor affecting the level of exhaust gas emissions is the driving style. Economic driving can lower fuel consumption by 10–20%.
Since the most significant environmental impact over a tyre’s life cycle comes from fuel consumption during use, the following diagram presents a tyre’s environmental impacts as the carbon footprint.
We participate in the research on the potentially harmful effects of micro polymers
Motor vehicles have been brought up as one of the sources of microplastics that are ending up in seas and other bodies of water. In the context of tyres, the term “microplastics” is somewhat misleading because tyres contain rubber rather than plastic. However, plastic and rubber are both polymers.
Many publications include the dust created during tyres’ contact with the road – i.e. wear particles from the tyre and road surface – under micro polymers or microplastics. Out of the particles that are generated, roughly one half comes from the tyre and the other half from the road surface. As the particles are quite heavy, most of them settle along roads, a small fraction of them remains airborne and some are swept into bodies of water by rainwater.
As a tyre manufacturer, we are responsible for the safety of our products. Friction between the tyre and the road is a significant safety factor and it is required for a tyre to grip properly. Friction also causes tyre and road wear, resulting in wear particles. In tyre design, we aim for the best combination of wear durability on the one hand and grip and safety characteristics on the other in order to optimise the tyre in terms of road safety and eco-friendliness.
Additional research is required
The current research has noted that, in fresh water areas, particles in sediments may pose a low risk to some aquatic organisms. However, additional research is required in order to determine whether the particles that enter bodies of water pose harm to the ecosystem or human health.
One important aspect of reducing the harmful impacts of driving is how we can prevent particle emissions from traffic or control them in an eco-friendlier way from the infrastructure perspective. Such areas for improvement could include sewer systems, ditch embankments or water purification.
We are actively following the studies on this topic and participate in external studies ordered by ETRMA and other organisations. The latest ETRMA Cardno study will be published in early 2018. The ongoing research on the tyre and road wear particles and on microplastics in general is more comprehensive than before. Reliable field and laboratory tests for understanding the nature, harmful impacts and routes of entry of the particles are required because many of the current estimates are based on mathematical models and calculations.
We are committed to continuous improvement and are developing our products and functions to be even more eco-friendly. We take human safety and health very seriously. If future research indicates that micro polymers are harmful, we will react accordingly and look for new solutions.
Retreading offers eco-friendly driving
The Nokian Noktop retreading complements our service range and brings cost savings and eco-friendlier kilometres to professional driving. Tyre retreading allows the operator to save money, resources and the environment. A good tyre carcass can easily be retreaded two times, which cuts tyre costs by approximately 30%.
CO2 emissions are generated during tyre production as well as driving. Retreading has a significant impact on the carbon footprint of tyres: manufacturing a new tyre results in approximately 220 kg of CO2 emissions, whereas the figure for retreading is only approximately 40 kg. Furthermore, each retreading operation saves 40 kg of rubber and 70 litres of oil per tyre compared to new tyres. Our new Nokian E-tread product family provides even higher raw material and energy savings. As a result of our product development efforts, we are able to recycle our tyres’ excellent tread rubber compound even more efficiently without compromising on quality.
Our winter tyres for trucks and buses and our Noktop retreading materials use a Cap/Base structure which is optimised for the seasons in the north. Its tread is composed of two layers. When a tyre is fitted in the autumn, the softer top layer (Cap) provides winter grip. The top layer will wear out by the spring, revealing the harder rubber compound (Base), which ensures that the tyre delivers sturdy performance in the following summer.
Where do tyres end up after use?
Approximately 3.2 million tonnes of used tyres are discarded each year in Europe. Luckily for the environment, discarded tyres are not worthless and can serve various reuse or recycling applications. Among other things, the tyres can be used in noise barriers along motorways or as an elastic base material in horse riding arenas.
If tyres are not appropriately recycled, they will end up in the environment or pile up in garages. The recycling rate of tyres in Finland is high compared to many other countries. In 1995, Nokian Tyres and other companies in the tyre industry established the Finnish Tyre Recycling Ltd in order to promote the centralised collection and utilisation of tyres nationally. In Finland, nearly 100% of tyres are recycled. In all of Europe, for example, the figure is 95%. The rest of the tyres are taken to landfills. In Russia, the tyre recycling rate is low. According to local legislation, in 2017, our tyre recycling had to be equivalent to 20% of our total sales in Russia, and we met that target.
Part of recycled tyres is utilised for material; they are shredded or granulated to replace rock materials in various road construction and civil engineering applications. Rubber chips are light, insulate moisture and maintain their form. They support the road surface and make asphalt quieter. The flexible properties of rubber are put to use once more when it is reused as a base material for sports venues.
Retreading is one of the best recycling methods. If the carcass of a tyre is undamaged, it can be retreaded. Bus and truck tyres, for example, can be retreaded up to 2–4 times.
Another way to utilise recycled tyres is to combust them for energy, as the heating value of tyres is close to that of oil. The use of recycled tyres as an energy source has been growing for years and, today, approximately half of the tyres recycled in Europe are used in waste-to-energy applications. We are constantly looking for new ways to recycle and utilise tyres.