The reason why the rubber at the hot sulfur vulcanization joint area of the conveyor belt is harder.

After connecting the conveyor belt, we often find that the joint area is harder than other areas. The vulcanization bonding process of the conveyor belt is actually a continuous cross-linking process of the vulcanized rubber. Since vulcanization requires heating, pressure, and a relatively long time, after a long period of vulcanization, the hardness of the vulcanized rubber increases, making the joint area feel harder. The strength of the conveyor belt joint is lower than that of the normal belt body. Generally, when connected mechanically, the joint strength is only 40-50% of the belt body strength. When cold bonding quality is good, the joint strength can reach 60-70%, and hot bonding joint strength can reach 80-90% (correct joint method, no quality defects). Due to the lower strength of the joint area, if the bonding method is incorrect, the joint strength will be even lower, such as cutting, sanding that damages the next layer of fabric, over-sanding, insufficient overlap length, not enough steps, poor rubber performance or vulcanization failure of the rubber joint, over-sanding of steel wire rope, rust on steel wire rope, etc., the strength of the joint area will be greatly reduced. In use, it is prone to the joint area breaking off. Additionally, if the conveyor belt does not use sealing glue or the bonding direction of the joint is incorrect, the joint area is prone to cracking (surface glue area).