Tires tread compound

Guanidines. Guanidines (10) were one of the first aniline derivatives used as accelerators. They are formed by reaction of two moles of an aromatic amine with one mole of cyanogen chloride. Diphenylguanidine (DPG) has enjoyed a resurgence ia demand as an activator for sulfenamides and a co-accelerator ia tire tread compounds which employ siUca fillers for low rolling resistance. Guanidines alone show too Htde activity to be extensively used as primary accelerators. There were no U.S. producers as of mid-1996. 

Natural mbber was also used extensively in its oil-extended form in winter tires in the 1970s (57). Use of oil-extended natural mbber treads, found to have excellent traction on ice and snow, superseded studded synthetic mbber treads when studs were banned in certain countries and states owing to the damage they cause to partially cleared roads. This concept has been extended into aH-season tires, which account for over 75% of original equipment and replacement tires in the United States. It has been shown (58) that part replacement of styrene—butadiene mbber (SBR) in the formulation of aH-season tire tread compounds with oil-extended natural mbber increases ice and snow traction, reduces rolling resistance, and has no effect on normal wet grip. Also, there is only a minor trade-off in wear performance, because below a tire surface temperature of approximately 32°C, the wear of natural mbber is superior to SBR, whereas above this temperature the reverse is tme (59). Thus, wear of an aH-season tire ultimately depends on the surface temperature of the tread over its annual cycle of temperatures. 

On the dusted track the diminished adhesion friction component is clearly apparent for all three rabbers when comparing them with the master curves on the clean track The friction plateau observed for the rubbers filled with 50 pphr black which is typical for tire tread compounds is observed for most rubbers, as shown in Figure 26.5. 

Friction Coefficients and Relative Ratings of Four Tire Tread Compounds at 4.5°C Ice Surface Temperature and a Speed of 0.5 km/h... 

Figure 26.33 shows the side force coefficient as function of log speed for different temperatures at a constant load and slip angle for a tire tread compound based on 3,4 cw-poly-isoprene, a polymer... 

FIGURE 26.36 The side force coefficient of an OESBR black-fiUed tire tread compound on wet blunt Alumina 180 as function of log a v obtained at three speeds and five temperatures (black open squares) with a quadratic equation fitted to the data (black solid line). The red marked points were obtained at one speed for five temperatures with the dotted red line the best fitting quadratic equation, indicating the risk of extrapolation with a limited set of data. 

Experiments carried out at a constant speed over a range of temperatures showed, however, that for tire tread compounds the temperature dependence of abrasion, although smaller reaches in this case, too, a minimum at a particular temperature as shown in Figure 26.51 and rises sharply with a further decrease in temperature. 

FIGURE 26.55 Abrasion surface appearance of a natural rubber (NR) black-fiUed tire tread compound for sliding abrasion at different temperatures. 

FIGURE 26.61 Log (abrasion) of an OESBR and a natural rubber (NR) tire tread compound as function of load at different slip angles at a speed of 19.2 km/h. left Abrasion loss of the OESBR compound as function of load. Right the relative wear resistance rating of natural rubber (NR) to the OESBR as function of load for different slip angles. 

Also shown is the relative rating between the OESBR compound and an NR + black tire tread compound. At the smallest slip angle the rating of the NR is better than the OEBR but decreases with the load. As the slip angle is increased the rating reverses. 

FIGURE 26.65 Log (abrasion) as function of log (energy dissipation) for a commercial tire tread compound at three different speeds. Surface Alumina 60. 

FIGURE 26.66 Log (abrasion) as function of log speed for three different tire tread compounds. Load 76 N, slip angle 14.6°. Surface Alumina 60. (From Grosch, K.A. and Heinz, M., Proc. IRC 2000, Helsinki, 2000, paper 48.)... 

FIGURE 26.68 Log abrasion as function of log energy and log speed for a tire tread compound. 

Relative Ratings of Four Passenger Commercial Tire Tread Compounds for Which Road Test Ratings Were Available as Function of Log Energy and Log Speed... 

FIGURE 26.72 Log tire wear as function of log slip angle obtained with the MRPRA trailer for three tire tread compounds. 

During the last 50 years the understanding of the very complex phenomenon of friction and abrasion of tire tread compounds and their relation to traction and wear has progressed steadily. This chapter tries to trace the main strands of this story. Some details may still be missing but the main points are now clear. 

Increasing price of crude oil has built up pressure on tire and automobile industry to develop low rolling-resistant tire with better traction. Combination of carbon and silica with coupling agent (dual filler technology) shows low RR with better traction and skid resistance in tire tread compound. Carbon black developed by plasma process and nanostructure black are other new significant developments in filler technology. 

M.J. Wang, P. Zhang, and K. Mahmud, Carbon-siUca dual phase filler, a new generation reinforcing agent for mbber Part EX. Application to tmck tire tread compound. Paper 32A, Presented at a meeting of the Rubber Division, ACS, Dallas, Texas, April 4—6, 2000. 

A. K. Bhowmick, Yeast as coupUng agent for com filler in tire tread compound. Progress in Rubber, Plastics and Recycling Technology, 21(3), 231, 2005. 

S. Bandyopadhyay, S. Dasgupta, S.L. Agrawal, S.K. Mandot, N. Mandal, R. Mukhopadhyay, A.S. Deuri, and S.C. Ameta, Use of recycled tire material in NR/BR blend based tire tread compound Part II (with ground cmmh mhher). Progress in Rubber, Plastics and Recycling Technology, 22(4), 269, 2006. 

Tire shredding, mechanical, 21 470-472 nylon, 19 765-766 reclaimed rubber in, 21 784-785 Tire-to-energy facilities, 21 466 Tire tread compounds, composition of, 21 806t... 

Ultrahigh-frequency (UHF) energy may be used for preheating and precuring rubber compounds for continuous vulcanization (CV) of rubber, containing carbon black, for such applications as weather stripping, tubing, hose, and. in some instances, tire tread compounds. 

Figure 32 shows that the RPA can predict the quality of mix for a generic tire tread compound. As noted, the RPA uncured tan S correlates to the quality or state of mix. This RPA parameter also relates to percent carbon black dispersion [122]. 

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