The Nynas senior advisor and former Nokian Tyres winter tire expert reveals how environmental legislation has impacted on the production of popular tire oils.
How has the winter tire market grown in recent years?
The winter tire market is growing at a 4.4% year-on-year rate. Increasingly more countries have put in place legislation to promote winter tire use. There has consequently been a lot of interest in developing better winter tires. This has led to the creation of new materials such as polymers, reinforcing fillers, rubber chemicals and tire oils which are specifically designed to improve the performance of tires in winter conditions.
However the past three to four winters in Europe have been really mild, so development in the tire market has not fully met expectations. Yet sudden changes in weather conditions seem to have become apparent. Hence safety is more and more important for consumers who want to get from one place to another without having to worry about the conditions they’re driving in.
What are the current challenges in winter tire development?
I joined Nynas in early 2016 and prior to that I worked for Nokian Tyres, which is known as one of the leading winter tire manufacturers in the world. Around 75% of my time was focused on winter tire development, so I am now an expert in that field. One of the best tools to improve winter tire performance is using tire oil. In a winter tread compound, oil loading is typically high, up to 35-55phr. Having joined Nynas, it was natural that we would focus even more on helping our customers to develop tires for snowy and icy conditions.
Winter traction is mostly governed by tread rubber compounding. The biggest challenge lies in the need of the compound to remain soft and flexible at extremely cold temperatures; meanwhile it must exhibit sufficient stiffness when the temperature increases and the road surface is wet or dry. The requirements differ remarkably from summer tires – there is basically one more dimension to them.
Instead of the ‘magic triangle’, I often say that in winter tire development it is a ‘magic square’. In addition, tread designers have done their best to improve traction even further. A tread with a high degree of siping provides the low stiffness as both the design and the compound are ‘soft’.
For many tire producers changes that are taking place in oil manufacturing that may also create challenges. Group I refineries are being shut down due to environmental and safety reasons, leading to a decreased manufacturing capacity of many popular tire oils. With a 2016 investment in naphthenic oil manufacturing capacity, Nynas aims to ensure that tire developers have enough tools in their compounding toolbox.
How has Nynas developed it products to meet these challenges?
In the tire industry, Nynas is well-known for supplying oils that help reduce rolling resistance and improve fuel economy. However what is maybe a little less known is how some of these oils are also ideal for making tires with improved winter and ‘just-above-zero-degrees’ performance.
Together with our customers we develop new grades that meet the most difficult requirements in a sustainable way. We also work very closely with other raw material suppliers so that benefits – e.g. new polymers and fillers – can be fully utilized both in terms of tire performance and tire manufacturing efficiency. In the paper presented at Tire Technology Expo Conference in 2017, we have shown that low temperature stiffness of tread compounds can be greatly reduced by appropriate selection of the tire oil. This provides improved winter traction without greatly affecting traction in other conditions.