Goodyear continued his research for the means to make a better from of rubber without the stickiness. He discovered that rubber was charred and not melted by boiler sulfur. The famous vulcanizing process was discovered and was later patented in 1844. Vulcanization was to revolutionize the rubber industry. Sadly, Goodyear was not much of a businessman and was unable to profit financially from his discovery. He died a poor man on July 1, 1860 and six of his twelve children also eventually died from diseases brought on by the Goodyear family's persistent poverty. Charles Goodyear never saw a penny of the earnings from Goodyear Tire & Rubber Co. since the company was formed nearly 40 years after his death .

II. Tire Production

A. Tire Statistics

Some key tire production statistics for 1998-1999 are given in the following table :

B. Raw Materials

In order to manufacture a tire the major raw materials required are: fabric (steel, polyester, nylon, or combinations of these), rubber (synthetic and natural types: hundreds of different types of polymers), reinforcing chemicals (carbon black, silica, resins), anti-degradants (ozonants, paraffin waxes), adhesion promoters (cobalt salts, brass on wire, resins on fabric), curatives (cure accelerators, activators, sulfur), and processing oils (oils, tackifiers, softners).

C. Processing & Production

The tire making process (see schematic below) starts by mixing different varieties of rubber with process oils, carbon black, pigments, antioxidants, accelerators and other additives, each of which contributes certain properties to the compound .

Figure 1: Schematic of the Tire Production Process - click on photo for larger view

These ingredients are mixed in giant blenders (called banbury mixers) under tremendous heat and pressure. The ingredients are blended together into a hot, black gummy compound that will be milled. The cooled rubber takes several forms. Most often it is processed into carefully identified slabs that will be transported to breakdown mills. These mills feed the rubber between massive pairs of rollers, repeatedly feeding, mixing and blending to prepare the different compounds for the feed mills, where they are slit into strips and carried by conveyor belts to become sidewalls, treads or other parts of the tire.

Still another kind of rubber coats the fabric that will be used to make up the tire's body. The fabrics come in huge rolls, and they are as specialized and critical as the rubber blends. Many kinds of fabrics are used: (i.e. polyester or nylon). Most of today’s passenger tires have polyester cord bodies.

Another component called a bead, shaped like a hoop. It is made of high-tensile steel wire, which will fit against the vehicle's wheel rim. The strands are aligned into a ribbon coated with rubber for adhesion, then wound into loops that are then wrapped together to secure them until they are assembled with the rest of the tire.

Radial tires are built on one or two tire machines. The tire starts with a double layer of synthetic gum rubber called an inner liner that will seal in air and make the tire tubeless. Next come two layers of ply fabric, the cords. Two strips called apexes stiffen the area just above the bead. Next, a pair of chafer strips is added, so called because they resist chafing from the wheel rim when mounted on a car. The tire building machine pre-shapes radial tires into a form very close to their final dimension to make sure the many components are in proper position before the tire goes into the mold.

Next      Back