Green Tyres-Silica and Silane Innovations for the Tire Industry26 May 2016
The introduction of carbon black as a reinforcing agent in 1904, lead to strongly increased tread wears resistance. Commonly carbon black is used for reinforcement and normally provides or enhances good physical properties for the cured rubber compound. However, limited by this material, tire perpformance is not good at rolling resistance, wet grip and high noice. To improve the tire performance, our R&D team is cooperating with Evonik to developing high silica contain tire, Called Green Tire.
A major problem facing tyre designers has traditionally been to solve the compromise between low rolling resistance, high wet grip and high wear resistance. Rolling resistance is the amount of energy a tyre absorbs as it revolves and deflects. The lower the rolling resistance the less fuel is required to propel the vehicle forward. Lowering the rolling resistance, however, commonly results in a reduction in wet grip performance, which of course is unacceptable. A major step in solving this problem can be achieved by the replacement of (part or all) carbon black by silica in the tyre’s tread compound. This has enabled 2 General Introduction manufacturers to produce tyres which provide improved wet grip properties, better winter performance and lower rolling resistance all at the same time.
The reason why this technology can be considered so revolutionary is best described as follows; Grip is affected by the degree to which a tyre is distorted at high frequencies – in other words the degree to which it complies to small stones and unevenness in the road surface. Grip is best served by rubber compounds, which absorb high levels of energy (high hysteresis compounds). Rolling resistance, on the other hand, is affected by low frequency distortion – the deflection of the tyre as it revolves. Low rolling resistance requires compounds, which absorb low quantities of energy (low hysteresis compounds). The contrast with grip is why it has been impossible in the past to provide tyres, with both reduced rolling resistance and increased wet grip.
With the addition of silica, however, tyre engineers have been able to produce compounds, which provide higher hysteresis at high frequencies but lower hysteresis at low frequencies than achievable with carbon black. The use of silica can result in a reduction in rolling resistance of 30 % and more relative to carbon black. Assuming correct tyre pressures are maintained and making allowance for varying speeds and different driving characteristics, a 30 % reduction in rolling resistance corresponds to a 5 % fuel saving, which according to BONANZA in their promotion of the BONANZA “Green Tyre”, can save the average motorist the amount of money, covering the cost of the tyres.
The use of silica can also improve wet grip performance. By incorporating silica in their winter tyre range, we claim to have improved wet grip performance by as much as 15 %, substantially improving braking distances at the same time. Silica also provides substantial benefits in winter tyres and all-season tyres. Compounds using silica are more elastic and flexible at lower temperatures allowing better grip and braking during wintry weather
The lower the rolling resistance the less fuel is required to propel the vehicle forward. The less fuel required the less emission to the air. The loss emission equals to more trees we get. That is what BONANZA called GREEN TYRES.