Rubber Industries

Natural rubber (latex—grown from plants)
Synthetic rubber (made artificially in a chemical plant or laboratory)
It takes several distinct steps to make a product out of natural rubber. First, you have to gather your latex from the rubber trees using a traditional process called rubber tapping. That involves making a wide, V-shaped cut in the tree’s bark. As the latex drips out, it’s collected in a cup. The latex from many trees is then filtered, washed, and reacted with acid to make the particles of rubber coagulate (stick together). The rubber made this way is pressed into slabs or sheets and then dried, ready for the next stages of production.
By itself, unprocessed rubber is not all that useful. It tends to be brittle when cold and smelly and sticky when it warms up. Further processes are used to turn it into a much more versatile material. The first one is known as mastication (a word we typically use to describe how animals chew food). Masticating machines “chew up” raw rubber using mechanical rollers and presses to make it softer, easier to work, and stickier. After the rubber has been masticated, extra chemical ingredients are mixed in to improve its properties (for example, to make it more hardwearing). Next, the rubber is squashed into shape by rollers (a process called calendering) or squeezed through specially shaped holes to make hollow tubes (a process known as extrusion). Finally, the rubber is vulcanized (cooked): sulfur is added and the rubber is heated to about 140°C in an autoclave (a kind of industrial pressure cooker).
Rubber is used to make a variety of things.
 

Tires: Modern tire technology blends a unique mix of chemistry, physics and engineering to give consumers a high degree of comfort, performance, efficiency, reliability and safety. Many tires are custom-designed to meet the stresses and performance needs specified by the maker of a particular model vehicle. The production process begins with the selection of several types of rubber along with special oils, carbon black, pigments, antioxidants, silica, and other additives that will combine to provide the exact characteristics wanted. Separate compounds are used for different parts of the tire. A machine called a banbury mixer combines the various raw materials for each compound into a homogenized batch of black material with the consistency of gum. The materials are then sent to machines for further processing into the sidewalls, treads or other parts of the tire. The end result is called a “green” or uncured tire. The “green” tire is placed inside a mold and inflated to press it against the mold, forming the tread and the tire identification information on the sidewall. Then it is heated at more than 150o C in a gas steam boiler for twelve to fifteen minutes, vulcanizing it to bond the components and to cure the rubber.
 

Gloves: Prior to the production the hand-shaped molds are first extensively washed in hot water (which comes via a gas fired water heater) and chlorine to ensure there is no residue from previous batches. They are then dipped into a mixture of calcium nitrate solution and calcium carbonate. The molds are dipped into the latex compound, with the duration of the dip determining the mil thickness of the gloves. The freshly molded gloves are next leached in a mixture of hot water and chlorine, which removes residual latex proteins and chemicals. After drying, the gloves are rinsed in hot water to remove latex proteins. The gloves are then sent in gas fired industrial tumbler to remove any remaining powder.
 

Rubber Bands: Post the collection and purification of the latex, the rubber is shipped to a factory. Here, the slabs are machine cut into small pieces. The rubber is then mixed with ingredients such as sulphur to vulcanize it, pigments to color it, and other chemicals to increase or diminish the elasticity of the rubber bands. The next stage is known as Milling, here the rubber is heated and flattened in a gas fired milling machine. After the heated, flattened rubber leaves the milling machine, it is cut into strips. The next stage is curing, here the rubber is forced over aluminium poles called mandrels, which have been covered with talcum powder to keep the rubber from sticking. Although the rubber has already been vulcanized, it’s rather brittle and needs to be cured. In order to do this, the mandrels are loaded onto racks that are steamed and heated using gas. The rubber is then removed from the mandrels and washed, it in then fed into another machine that slices them into finished products.