In the process of general conveyer belt production, unmodified aramid cords are used. Numerous tests have shown that the loss of the breaking force of those cords are large during the bending process. For example, a standard aramid cord, tested on a planetary bending testing machine (HALT-test),the residual breaking force of the cord decreases by 41.4%, after one million bending cycles.Under the same test conditions, the residual breaking force of a modified aramid cord decreases by only 2.2%.
It is necessary to pay attention to the change of residual breaking strength when the material is used continuously. The rapid decline of residual breaking force will lead to premature damage of the belt. Through the change and analysis of residual breaking force, the aramid fiber construction shall be designed specifically for the application.
The reason why the modified aramid cord has a low tensile strength loss when the belt is under stress is that during the modification process, the aramid yarns has gone through four levels of physical and chemical treatment to eliminate the internal stress concentration of the yarns, and to maintain the stability of the tension when the yarns is running.
A large number of tests show that under the condition of frequent transmission/bending, the belt service life of the modified aramid cord is 1.5-3 times longer than that of a standard aramid cord and steel wire.