How is Car Tire Rubber Made?
Car tire rubber is primarily made by mixing and heating several key raw materials to create a durable, flexible compound.
The process begins with the careful selection and combination of ingredients essential for the performance characteristics of a tire.
First, raw materials such as natural rubber, synthetic rubber, carbon black, and various chemicals are mixed together in a large machine called a Banbury mixer. This powerful internal mixer blends the components thoroughly under controlled conditions.
This mixture is then heated to a high temperature, which causes it to become a sticky compound that can be molded into different shapes. This initial compound, often called "masterbatch," is the foundation of the tire's rubber components.
Key Raw Materials
A typical rubber compound for tires includes:
- Natural Rubber: Provides strength and elasticity.
- Synthetic Rubber: Offers durability, abrasion resistance, and consistent quality (e.g., Styrene-Butadiene Rubber - SBR, Butadiene Rubber - BR).
- Carbon Black: A reinforcing filler that dramatically increases strength, durability, and wear resistance. It also gives tires their black color.
- Chemicals: A blend of various chemicals including:
- Sulfur (for vulcanization/curing)
- Accelerators (to speed up curing)
- Antioxidants (to resist aging and cracking)
- Softeners and oils (to improve processing and flexibility)
Here's a simplified view of the main components:
| Material | Primary Function |
|---|---|
| Natural Rubber | Strength, Elasticity |
| Synthetic Rubber | Durability, Wear Resistance, Consistency |
| Carbon Black | Reinforcement, Durability, Color |
| Chemicals | Processing, Curing, Protection |
After the initial mixing and heating in the Banbury mixer, the sticky compound is often further processed through milling or extrusion to prepare it for the subsequent stages of tire manufacturing, such as building the tire layers and the final curing process (vulcanization) which gives the rubber its final shape and properties under heat and pressure.
