Vulcanized rubber, or cured rubber, is much stronger than traditional rubber. It can withstand greater pressure and stress and is far more elastic, which is why many manufacturers prefer using vulcanized rubber in their businesses. There are five basic methods used for curing rubber lining, which are autoclave, internal pressured steam, exhaust or atmospheric steam, chemical cure. and hot water cure.
Vulcanization techniques can vary, but they usually involve mixing crude rubber or other elastomeric materials with sulfur or another agent along with an activator, or accelerator. Accelerators are added so that vulcanization can occur at a lower temperature and with greater efficiency.
Extruded rubber products utilize soft non-vulcanized rubber that is forced through an extrusion die under pressure with sufficient heat to form the desired shape created by the die. Some typical types of rubber used in this process are Neoprene or EPDM. The end result is a rubber which is soft and pliable, formed to the desired shape of the finished product, such as gaskets, car molding, vibration pads, door seals, or countless others. These products would then need to be vulcanized, or hardened before use.
Vulcanization improves elasticity, hardness, tear strength, and resistance to organic solvents and abrasion. It also offers excellent resilience, low water absorption, and oxidation resistance and makes an excellent electrical insulator. This durability makes vulcanized rubber a great material for use in a number of products where durability and water resistance during rugged activities are of the utmost importance, such as athletic watch straps or rubber shoe soles. Any application requiring rubber can benefit from the added properties of vulcanization, and the process is common in the production of rubber hoses, shoe soles, insulation, vibration damper, erasers, shock absorbers, children’s toys, conveyor belts, rubber-lined tanks, hockey pucks and more.
However, the most common usage of vulcanized rubber is in tires. Tires are often reinforced with carbon black for even greater strength. More than one billion tires are manufactured worldwide on an annual basis, in a process referred to as Open Vulcanization.
In a tire manufacturing plant, “green” tires are placed in a steam press, or autoclave. This press is a hot pressurized mold using steam at a set pressure, which causes vulcanization, transforming the tire from a weak rubber to a strong elastic material. This process requires a constant and reliable temperature. Since direct contact between the Steam and Rubber occurs in the process, a supply of dry saturated steam at between 260 and 350 psi is consistently required. High steam dryness is also important to this process, which prevents any contaminants ruining the vulcanizing process.
Continuous vulcanization is a single-line operation, where the rubber product is continuously feed onto a cable or wire. Wire and Cable manufactures utilize continuous vulcanization to add insulation to most types of Power cables on an extrusion line. Bare wire enters a tube along with a vulcanizing medium, which requires a fixed temperature and pressure to adhere the rubber onto the wire, creating a close fitting and insulated electrical carrier.
Clayton Steam Generators will provide a constant supply of Dry, saturated steam, less than 1% moisture, at a steady pressure. With our fully modulating Steam Boiler and on-board mechanical steam separator, Clayton Steam Generators make a perfect match for both Open and Continuous Vulcanization.