Vulcanization is a technological process of interaction of rubbers with a vulcanizing agent, during which the rubber molecules are stitched into a single spatial network. This increases the strength characteristics of rubber, its hardness and elasticity, reduced plastic properties, the degree of swelling and solubility in organic solvents. Vulcanizing agents can be: sulfur , peroxides , metal oxides, amine compounds, etc. To increase the rate of vulcanization, various accelerator catalysts are used.
Charles Goodyear , who patented it in 1844, discovered the vulcanization process. The process is named after Vulcan , the Roman god of fire.
In the process of vulcanization rubber becomes rubber .
Vulcanization is usually a mixture of rubber with various components that provide the necessary operational properties of rubber: fillers (carbon black, chalk, kaolin, polydisperse silicic acid, etc.), plasticizers (oil and tall oil, factis , dibutyl phthalate, etc.), antioxidants (bisphenols, diamines, etc.), vulcanization accelerators (xanthates, thiazoles, sulfenamides, etc.), vulcanization activators (zinc oxide, magnesium oxide, etc.), scorch retarders (phthalic anhydride, N- neither rozodifenilamin and t. d.).
Car Camera Repair
When the car tire chamber gets punctured and begins to release air, it is repaired, applying a patch of raw (unvulcanized) rubber and being vulcanized.
Crude (unvulcanized) rubber has a plastic consistency, it can be crushed into a ball, it sticks to objects. Raw rubber is produced in sheets. From two sides it is covered with a polyethylene protective film.
The car camera at the puncture site is cleaned of dirt, and also make its surface rough for better adhesion (fine sandpaper ), degreased with gasoline . At the puncture site impose a patch of raw rubber and clamped in the vulcanizer.
Electric vulcanizer is a clamp , one of which sponge is a heating element. A raw rubber patch is tightly pressed against the chamber by a heating element . To prevent the curing of the heating element with the patch during vulcanization, motorists usually enclose a piece of paper .
When heated, vulcanization of raw rubber occurs, it becomes durable and elastic. The surface temperature of the heater (according to the instructions) is about 140-160 ° C. Upon reaching the specified temperature (the paper begins to change color), the heating is stopped, after full cooling, the vulcanizer is removed.
Electric vulcanizers produce stationary (large-sized, for automobile enterprises), portable (working from the mains 220 V ), portable (for repair in road conditions, from a car battery 12 V).
In the early stages of the era of automobilization, fire vulcanizers were used to repair automotive cameras. Here, the heating element is a “plate” into which a strictly defined portion of gasoline is poured and set on fire. The complete combustion of gasoline provides the desired temperature and the desired duration of the vulcanization process.
In the USSR, pyrotechnic heaters were also produced (disposable ersatz- vulcanizers): in a metal plate about 5 cm in diameter (corresponding to the average patch size) there was a combustible substance, a “plate” with a patch of raw rubber was pressed against an enclosure and some chemical was set on fire . After cooling, it was possible to insert the camera into the tire and continue the trip.
Docking conveyor belts
Conveyor belts are used in various industries. Often one has to face the necessity of their connection (joining) with each other. In such cases, use the method of hot, cold or mechanical vulcanization. The same problem arises when joining the ends (gluing into a ring) of the handrails of escalators .
Literature
- Sheypak A.A. History of science and technology. Part 1 - MGIU, 2007. - pp. 55-57. - 274 s. - ISBN 9785276016641 .
- Kalissky V.S., Manzon AI