Tyres are undoubtedly one of the most complex amalgamations of materials that exist in the world. There is, however, very little awareness about what constitutes them and where and how these different materials are used in tyres. So, in order to help you understand what constitutes these black rubber doughnuts, we decided to make an exhaustive list describing 13 different materials that are used to manufacture different types of tyres:
- Natural Rubber - Obtained by refining latex which is a natural milky colloidal liquid that is obtained from rubber trees through a process called latex tapping.
- Synthetic Rubber - Synthetic rubbers are a man-made elastomer synthesised from petroleum by using solution or emulsion polymerisation methods. The two main synthetic rubber polymers used in tyre manufacturing are butadiene rubber and styrene-butadiene rubber. These rubber polymers are used in combination with natural rubber. Physical and chemical properties of these rubber polymers determine the performance of different components in the tyre as well as the overall tyre performance (rolling resistance, wear and traction).
Another important synthetic rubber is halogenated polyisobutylene rubber (XIIR) commonly known as halobutyl rubber. This material makes the inner liner impermeable which helps in keeping the tyre airtight and inflated.
- Carbon Black - Carbon black is a by-product of incomplete combustion of petroleum. It has an uncanny resemblance with soot. Carbon black and soot can physically look very similar but are very different in terms of the relative amount of carbon, type of particulate carbon, and particle characteristics (size, shape, and heterogeneity) they have.
- Silica - Silicon dioxide is used to deliver better fuel efficiency and wet grip. The addition of the chemical also improves properties such as tear resistance, tensile strength and makes the tyre abrasion proof. This results in reduced wear and tear as well as improved levels of traction. It also reduces rolling resistance.
Also See: Rubber Shortage Sparks Trouble For Tyre Sector Despite Auto Revival
- Oil - Oil is used to soften the rubber.
- Antioxidant - Used to prevent oxidation of the rubber when the tyre reaches higher temperatures as it is full of air that contains oxygen.
- Sulfur - Used in the process of vulcanisation. Sulfur and zinc oxide, are crucial ingredients to transform rubber into a solid article during vulcanization or tyre curing. Curing systems shorten the vulcanization time and impact the length and number of crosslinks in the rubber matrix that form during tyre curing or vulcanization.
- Vulcanised accelerator - Accelerates the process of vulcanisation
- Polyester - Another polymer extracted out of petroleum that is used to construct body plys in passenger tyres. Other fabrics used for body plys are rayon cord fabric, nylon cord fabric and aramid cord fabric. They serve as the primary reinforcing material in the tyre casing and help the tyre keep its shape in different road conditions. They also provide additional endurance and performance characteristics to the tyre.
- Rayon - A natural fibre that is made from materials like wood and agricultural products that are regenerated and purified as cellulose fibres. It's a natural man-made fibre used in the body plys of passenger vehicle tyres.
- Steel wires - Steel wires are used for the construction of beads and steel belts in passenger vehicle tyres.
- Antiozonants - These are used to impede the effects of ozone exposure on the surface of the tyre. The main job of the antiozonant is to protect the tyres from dry rot or cracking due to ozone. As the element comes into contact with ozone, it leaves a brown residue on the surface of the tyre due to oxidation, also known as tyre bloom.
The rubber structure of the tyre is built in a way that allows the antiozonant to move forward to the surface, thus continuously providing the tyre with its benefits. As a result, the tyre remains pliable and UV/oxygen-resistant for a longer time. It is an essential defence that boosts the tyre's durability and shelf life.
Image Credits: Tyreasia
