1、 Causes of longitudinal tear of conveyor belt
（1） . the vibration and impact causes the fasteners to loosen and fall off, resulting in the falling of coal drop pipe lining plate, guide plate, etc.
（2） . foreign matters are mixed in the material, which are hard and angular, and the coal chute is blocked and squeezed.
（3） . the idler is damaged and the idler frame is scratched.
（4) . the conveyor belt is caught by the frame after serious deviation.
（5） The sweeper is drawn into the drum (return sweeper), the bolt is loose and there is a sign of bouncing.
2、 Causes of belt cracking:
（1） Due to the limitation of space size, the conveyor belt has many bending times.
（2） The joint has been vulcanized more than twice due to various reasons.
3、 Causes of tearing of vulcanization joint of conveyor belt
（1） The diameter of the reversing drum is small, and the bending stress borne by the conveyor belt is large.
（2） The vulcanization joint of the conveyor belt is of poor quality, especially if it has been vulcanized for more than two times, the strength of the joint decreases significantly, or the canvas layer is cut off during bonding, or the polishing leaks, and the strength decreases here.
（3） For reversible conveyors, because the upper and lower lapping can only be in one direction, they are easy to be scratched by the sharp corners of the sweeper, unloader and other equipment on the belt.
（4） The conveyor has short working cycle, frequent starting and large instantaneous tension.
4、 Reasons for damage of rubber covered surface of conveyor belt
（1） . the gap between the lining plate of the guide chute and the adhesive tape is inappropriate, resulting in abnormal wear, or foreign matters are embedded in the gap, resulting in abnormal wear or scratch.
（2） The material flow rate at the guide chute is inconsistent with the speed of the conveyor belt, and the drop is large, which accelerates the wear of the rubber surface.
（3） . the idler is damaged, resulting in abnormal wear or scratch of the belt.
（4） . operation against rules, welding slag scald during maintenance, and cleaner scratch, etc.
（5） If the tape slips, it will also cause abnormal wear of the tape.
During the use of the conveyor belt, the most common problems are: foreign matter scratch, local foreign matter damage, wear, perforation and so on.
Generally, the conveyor belt is partially damaged due to foreign matters. According to the traditional method, it shall be repaired, heated and vulcanized or scrapped and replaced after all disassembly.
It can be repaired with polymer rubber, which has super adhesion, excellent wear resistance and excellent tensile properties. The polymer rubber repair material is used to repair the scratch of the rubber conveyor belt on site without disassembly and thermal vulcanization. The repair cost is low and the time is short, so as to avoid major losses caused by scrapping, replacement and long-time shutdown. Moreover, the repaired conveyor belt can fully reach the service life of the new conveyor.
The thickness of the repair coating is controllable, the forming is fast and the operation time is short. The cured coating has very high cohesive strength, tensile strength, peel strength, good hardness, toughness and elongation. It can greatly simplify the repair construction process, with good self leveling and bright appearance. It can not only quickly repair the damaged rubber conveyor belt and rubber products, but also pre coat a protective layer on the surface of the products to prolong the service life.