Safe in the overtaking lane with zinc oxide in your tyres
In motor racing, tyres can make the difference between victory and defeat. In everyday life, tyres are key to achieving greater safety, better handling and durability: they must provide suspension, shock absorption, and ensure good tracking and optimal radial run-out. Above all, tyres must be capable of transmitting high forces both longitudinally and transversely to guarantee safe holding on the road – even when the road provides poor grip, is wet, slippery or covered in ice or snow. Tyres run well and reliably with zinc oxide. Zinc oxide improves safety by giving the tyre better crosslink density, thus improving strength and increasing resistance to ageing. A standard car tyre contains around 180 g of zinc oxide.
More than 150 different materials are used to manufacture a tyre. At the beginning of tyre production, there is a rubber mixture consisting of basic substances such as India rubber, fillers, sulphur and numerous chemical additives. To achieve permanent elasticity - the rubber should return to its original position following exposure to mechanical stress – vulcanisation is used. The vulcanisation process generates a network by the cross-linking of polymer chains and it is this network which gives the mixture its required strength. This gives rise to a highly elastic and tensile material – India rubber is transformed into industrial rubber.
The chemistry of this process is highly complex since a number of reactants are involved: Sulphur is relatively inert, which means that vulcanisation proceeds slowly, even at high temperatures; using sulphur alone would lead to a much lower number of crosslinks. The connections would also be chemically less stable. This could result in insufficient strength and reduced ageing stability.
For this reason and since some time back in 1900, India rubber has been cross-linked not just with sulphur, but also with a range of additives which, although these constitute a low percentage only in terms of weight, significantly improve tyre quality. One of these additives is zinc oxide. As a catalyst, it speeds up the vulcanisation process and increases the number of crosslinks per unit of volume (crosslink density). The addition of zinc oxide therefore increases the efficacy of the catalyst, makes the manufacturing process more efficient and guarantees optimal tyre strength. This makes zinc oxide an irreplaceable material as it is essential not least for durability, safety and good grip.
In collaboration with:
Sabina Grund (Engineer)
ZINC INITIATIVE in the WirtschaftsVereinigung Metalle [Metal Trade Association]
Am Bonneshof 5
Tel.: 0211 47 96 166
Fax: 0211 47 96 25 166