On the look for new renewable raw materials

On the look for new renewable raw materials

The EU has included natural rubber on the list of critical raw materials. Guayule is an opportunity not only for Nokian Tyres but also for the local agriculture and industry in Spain.

We actively look for and test renewable raw materials. Our aim is to find bio-based raw materials for various raw material groups, create eco-friendlier tires, and replace fossil raw materials. We will also reduce the use of harmful substances, thereby improving occupational safety in production. We were the first in our industry to give up the use of high aromatic oils.

Renewable raw materials are also used for improving tires’ properties and performance by modifying the compound property balance at varying temperatures. The use of new raw materials requires a great deal of product development efforts and testing in order to find the best combination of properties for a tire. In materials development, the use of renewable materials must not alter a tire’s safety characteristics.

The best progress has been made in the use of renewable raw materials with bio-based oils. They are used in order to replace synthetic oils that are based on crude oil. We also conduct research in order to investigate the use of recycled rubber sourced from used tires as a replacement for fossil carbon black.

The use of renewable raw materials has not required us to change our production processes or had any significant effects on the energy consumption in production. However, renewable raw materials often increase the raw material costs of tires.

Nokian Tyres' tire materials and their alternatives
Material % of a tire Sources Replacements and alternatives
Synthethic rubber 22 crude oil • Needs active engagement from raw material producers.
• Recycled rubber crumbs
Natural rubber 22 natural rubber  • Guayule as an alternative for natural rubber which is currently cultivated in South East Asia and some parts of Africa
• Recycled rubber crumbs
Fillers 28 silica, carbon black • Active research of different biobased fillers, for instance from forest industry side stream-based materials.
• Potential to use silica produced from rice husk in some products.
Reinforcement materials 15 steel, textile • Recycled steel is being used in our reinforcement materials.
• Researching the use of biobased or recycled sources for textiles.
Softeners 5 low PAH oils • Increase bio-oil and bioresin content in tires. Canola oil and tall oil already used, various vegetable oils researched.
Vulcanizers 6   • Reduction & elimination of harmful chemicals
Other chemicals 2   • Reduction & elimination of harmful chemicals

FINDING altervatives FOR NATURAL RUBBER

Guayule-based natural rubber is one of the active initiatives that Nokian Tyres is working on. We are currently testing the suitability of different guayule varieties to be cultivated in central Spain, near our new testing center in Santa Cruz de la Zarza.

As guayule originates from the desert, it can survive in very dry and poor soil conditions. It is a plant that does not exploit areas of any other vegetation or food production, on the contrary, it makes use of wastelands. Nokian Tyres is collaborating with local farmers, universities, research institutes, and companies in Spain. Guayule is an opportunity not only for Nokian Tyres but also for the local agriculture and industry.

Currently, natural rubber that is used in tires comes from rubber trees (Hevea Brasiliensis), which are growing in areas around the equator. This results in long logistics chains for tire manufacturers located in the north, which is bad for the environment and also costly. If guayule succeeds as an alternative source for natural rubber, it will shorten the transporting distance and reduce the CO2 emissions.

Conservation of natural vegetation in tropical areas would be another environmental benefit. The substantial use of toxic pesticides on rubber plantations in Southeast Asia is a problem for the environment. Also, the South American leaf blight (Microcyclus Ulei) poses problems for the cultivation. The majority of the rubber rees in Asia are clones of varieties highly vulnerable to this disease.

Guayule, however, grows in dry areas, and no major plant diseases have thus far been identified as potential problems. It is also hypoallergenic, unlike the normal Hevea rubber. This is a relief for many people working in the rubber industry, logistics, and trade.

In Spain, studies have been continued on the Parthenium argentatum variety of the plant: what is the best way to maintain it, how to fertilize it and how to remove any weeds that may compete with the plant. The results have been promising, and in 2020, the researchers have developed a sustainable way of managing the plant where no synthetic biocides are needed.

Also, researchers have made promising experiments with cultivating the plants on poor soils in total absence of irrigation. Instead of planting ahead of the hottest season of the year, the planting had been carried out in the autumn to allow the survival of the plants. To affirm the promising results, the planting was carried out again in the next fall.

The researchers are also exploring the opportunities of plant waste as a part of a circular economy project, in which all the co-products of the plant are utilized.

In January 2021, there was unusual snowfall in the region due to the Filomena storm and the Madrid region recorded the heaviest snowfall in several decades. Despite the heavy snowfall, most of the plants survived and only some replanting was necessary. The exceptional weather phenomenon provided us with important knowledge on the survival of the plant in low temperatures and the effects it has on different varieties of the guayule plant.

As the cultivation of the plant has proved to be successful, research has been concentrated on extraction tests and studies on how the extraction could be performed in the most effective and environmentally friendly way. Also, data gathering of seed collection, cleaning, processing and seed planting optimization has been going on actively. The focus of the work is now in our own laboratory where we have been examining different options to find the most favorable compounding alternatives for several tire components.

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