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The market for winter tyres is booming. An increasing number of countries are putting regulations in place. At the same time, existing regulations are also being tightened, not least by the European Union’s introduction of the 3PMSF (three peak mountain snowflake) symbol for true winter tyres, which places further demands on the tyres and the raw materials used to produce them.
“Winter tyres are facing new challenges. While in the past the greatest focus was placed on winter tyre properties such as ice grip, nowadays wet grip and rolling resistance play an increasingly important role in the overall equation,” says Dr Kamyar Alavi, Senior Technical Advisor, Tyre and Rubber Oils, Nynas Naphthenics.
However, where challenges can be overcome, they bring new opportunities, and according to Kamyar Alavi, this is certainly true for Nynas NYTEX® oils. In a recent study, comparing the winter tyre properties of compounds made with several different plasticisers in the NYTEX® range with those made with traditionally used grades such as TDAE (Treated Distillate Aromatic Extract) and MES (Mildly Extracted Solvate), he and his colleagues were able to establish that NYTEX® oils offer an elegant solution to boost the performance.
“We found that you are able to achieve an excellent balance of winter tyre properties when naphthenic tyre oils are used. Ultimately, you want to keep the dynamic stiffness at low levels at low temperatures to ensure enough traction on cold roads, without compromising traction in wet or dry conditions,” explains Kamyar Alavi.
The study showed that NYTEX® oils enable traction to be improved both at low temperatures and in wet conditions whilst a competitive performance can be achieved for rolling resistance, a finding confirmed by several previous Nynas studies.
Identified in the study as the best performing oil, NYTEX® 843 is a new product developed specifically to boost performance. Compared with TDAE, the oil showed a 27 % gain in dynamic stiffness, the property used as an indicator for traction at low temperatures. For NYTEX® 4700, the same parameter showed a gain of 11 %, whilst the oil also provided more improvement with regard to traction in wet conditions. Furthermore, NYTEX® 832 performed on a par with, or slightly better than MES.
“Taking into account sustainability, we also saw very promising performance results for our new bio-based oil, NYTEX® BIO 6200, indicating that this is a very viable contender for use as a plasticiser in winter tyres,” says Kamyar Alavi.
Winter tyre property balance
• Pitted against other plasticisers in a Dynamic Mechanical Analysis (DMA) study, several Nynas NYTEX® oils displayed excellent winter tyre properties. Compared with other tyre oils, these had:
- lower E* at -25°C, improving the flexibility and traction at low temperatures,
- higher tan δ at 0°C, improving traction in wet conditions,
- similar tan δ at 60°C, offering a competitive performance in rolling resistance.
• The results indicate that NYTEX® 843 is the best performing oil, closely followed by NYTEX® 4700, with the performance of NYTEX® 832 closely resembling that of MES. The bio-based NYTEX® BIO 6200 also showed an excellent balance of properties suitable for winter tyres.
Dr Kamyar Alavi is a Senior Technical Advisor and Group Specialist at Technical Development and Support, Nynas Naphthenics. He joined Nynas in 2010.