The process of producing rubber bands involves the creation of rubber tubes that are cut to produce the proper shape. In the beginning stage, raw rubber is kneaded and heated to soften it into a dough.
The kneaded rubber is removed in chunks and collected to form sheets. The chunks are put through huge rolling pins that press them into wide, thin, deformed pieces of rolled rubber dough. As the sheets exit rollers, they are cut into uneven strips and bundled for easier movement and control for the addition of chemicals.
During the rolling process, sulfur and chemicals are added that make the rubber more elastic, pliable, and stronger. The bundles from the first rolling are rolled second time into thin sheets that are much like cloth. The thin sheets are twisted into small bundles to be placed in the extruding machine.
The extruder shapes the rubber sheets into long tubes that are cut to lengths for further processing. As the tubes of rubber leave the extruder, they are filled with air and talcum powder to keep the walls of the tubes from collapsing and sticking. As the tubes exit the extruder die, they pass into a trough of water to be cooled.
While the long tubes of inflated rubber pass through the cooling water, they deflate as air is released. The cooled tubes are placed over long round poles, or dies, for the curing process. The poles give the tubes the rubber band shape and diameter. The talcum powder, from the extrusion process, makes sliding the tubes of rubber on to the shaping poles much easier and keeps the tubes from sticking during curing.
The tubes are placed in bundles that are loaded into a steam oven. The extreme heat of the steam oven vulcanizes the rubber, which adds to its tensile strength and elasticity. Once the tubes and molds are removed from the oven, the tubes of rubber are taken off the molds.
As a final step, before the rubber tubes can be cut into rubber bands, the tubes are rinsed to remove the talcum powder and other residue. When they are sufficiently dry and rinsed, they are sent to be cut.
Drying makes the rubber tubes too dry for cutting, which requires moistening them during cutting. To cut the tubes to the proper width, they are fed into a preprogrammed cutter that cuts them to the exact widths to form the final rubber bands. Over a half million rubber bands are produced every hour using this process.
Though rubber is the most common component for the manufacture of rubber bands, there are several other materials that have been developed to produce them, such as ethylene propylene diene monomer, synthetic polyisoprene, and various silicone compounds. The selection of the type of material depends on how the band will be used.
The main purpose of rubber bands is to hold a group of items together. Many of us find them on commercial products from a store. Though this is a common use, they are also used in agriculture, packaging, stationery, fisheries, transportation, and several other industries.
The largest user is the United States Postal Service, which orders millions of tons of them every year. Their original use and continuing use are to keep magazines and newspapers rolled tightly for delivery. As any florist can tell you, they are essential for the creation of bouquets of flowers.