The Trade-off Between Abrasion Resistance and Heat Build-up in Carbon Black

In the tire industry, the trade-off between abrasion resistance and heat build-up is a long-standing issue. As the primary reinforcing filler for rubber, carbon black's particle size and structural parameters directly dictate the inverse relationship between these two performance indicators. From a materials science perspective, this conflict is rooted in the intrinsic link between the reinforcement mechanism of carbon black and hysteresis loss.

The Dual Impact of Particle Size and Structural Parameters

Reducing particle size is the most direct way to improve abrasion resistance. A smaller primary particle size results in a larger specific surface area, thereby increasing the interfacial contact area between the carbon black and the rubber matrix and raising the density of physical cross-links; this significantly enhances the mechanical strength and abrasion resistance of the vulcanized rubber. Small-particle-size grades, such as N234, excel in tread compounds precisely because they impart higher hardness and modulus (stress at a specific elongation) to the material, enabling it to resist cutting and abrasion from the road surface. However, this same mechanism sets the stage for heat build-up issues: the high specific surface area associated with fine particles implies a greater number of carbon black aggregate interfaces. During cyclic deformation, the slippage of rubber molecular chains against the carbon black surface, combined with the repeated breakdown and reformation of the filler network, consumes significant energy. This energy dissipates as heat, manifesting as increased hysteresis loss.

The impact of structural degree cannot be overlooked either. High-structure carbon black aggregates feature extensive branching, making it easier to form filler networks within the rubber; while this enhances reinforcement, it also intensifies the Payne effect. Under dynamic loads, the repeated breakdown and reconstruction of these filler networks amplify energy loss, leading to increased heat build-up under compression. Comparative studies have shown that while styrene-butadiene rubber (SBR) filled with N234 carbon black offers excellent abrasion resistance and strength, it exhibits a relatively high loss factor at 60°C and persistently high dynamic heat build-up. The loss factor at 60°C is a key metric in this trade-off; it directly indicates tire rolling resistance and correlates strongly with heat build-up tendencies. Conventional high-abrasion carbon blacks often perform poorly in this regard because their interaction with the rubber is primarily based on physical adsorption, making interfacial slippage difficult to avoid.

 A Shift from Trade-offs to Controlled Regulation

In recent years, the industry's approach to resolving this conflict has shifted from simple trade-offs to precise regulation. The L21 carbon black introduced by Heimao Shares offers a noteworthy case study. Its technical strategy does not rely solely on adjusting a single dimension—such as particle size or structure—but rather employs the synergistic optimization of high-structure design and aggregate size distribution, combined with surface functionalization. This approach enhances the chemical bonding between the carbon black and rubber molecular chains, thereby reducing interfacial slippage during dynamic deformation. Test data show that L21 exhibits a 2.8% reduction in DIN abrasion volume compared to N134, alongside a 14% decrease in the 60°C loss factor and a 23% drop in heat build-up under compression. These results demonstrate that abrasion resistance and low heat build-up are not mutually exclusive; the key lies in finding a balance between the carbon black's intrinsic structural parameters and interfacial chemistry.

Academic research corroborates this direction. Studies have produced low-hysteresis, high-abrasion-resistance carbon black by synergistically regulating parameters such as oil absorption value, specific surface area (adsorption), and compressed oil absorption value. Compounds filled with this material showed a reduction in DIN abrasion of over 20% compared to N234, with a simultaneous decrease of approximately 10% in the 60°C loss factor. Mechanistic analysis attributes this to enhanced interfacial bonding—driven by rough surface topology and a rich microcrystalline structure—which restricts rubber molecular chain movement and reduces internal frictional slippage, naturally lowering heat build-up.

From an engineering perspective, resolving this conflict also requires adjustments at the formulation level. Excessive carbon black loading exacerbates filler networking and increases hysteresis loss; consequently, balancing abrasion resistance and heat build-up often necessitates the co-use of silica or the optimization of filler content. Ultimately, however, the structural design and surface modification of the carbon black itself remain the foundation for overcoming this bottleneck. Only when the interaction between carbon black particles and rubber shifts from "physical mixing" to "chemical interlocking" can the zero-sum game between abrasion resistance and low heat build-up truly be broken.