The desulfurization regeneration of the rubber timing belt material is a comprehensive result of sulfide reduction, thermal depolymerization, oxidation, mechanical action and other functions.
(1) Mechanical action
The mechanical energy can destroy the C-S, C-hair molecular chain segment, as a result, the cross-linked network structure of the rubber molecule is cut off. Grinding can also separate the association between the molecule and the surface of the carbon black. Most of these fractures occur at lower temperatures.
(2) Thermal effect.
Thermal energy accelerates the movement of molecules, which leads to the breaking of molecular chains. There is obvious thermal cracking at about 80 ℃, and the cracking speed is accelerated at about 1500C. After that, the temperature can be doubled for every 100C increase in temperature.
After thermal cracking, there are reactive free radicals at the ends of the cracked molecules.
(3) The role of oxygen
The presence of oxygen causes hydroperoxides in the depolymerization of rubber timing belt materials, which makes molecular chains more likely to break and accelerates the cracking rate. At the same time, the active radicals generated by the cracking can recombine. It will slow down the cracking rate. For vulcanizates containing double bonds on the side chain, the cracking rate is slower.
According to the classification, the preliminary decision is made on whether to renovate and the type of refurbishment. Then the original product is tested for physical properties such as the type of core, tensile strength, and adhesion strength to further determine whether it can be refurbished and determine the type of refurbishment and the raw materials used. For those that can be refurbished, peel off all the covering glue, and for those that need repairing, just peel off part of the covering glue. The stripped conveyor belt is sanded again to remove the remaining rubber on the belt core, cut off the corroded or damaged part of the belt core, coated with glue, dried and glued to the canvas that has been rubbed, and finally glued on the cover. Then use flat steam vulcanization or low temperature vulcanization, and then repaired and processed to get refurbished products.