Low density, small modulus of elasticity, reduced impact force, resulting in reduced fatigue damage, the life of the valve is greatly prolonged, under normal circumstances, its life is much better than that of metal valves. It has good sealing performance, less air leakage and good running-in performance of valve plates. The flow characteristics are superior to those of similar metal valves, which are resistant to the impact of solid particles and droplets. The propagation speed of crack is slower after the valve plate is broken. It has low noise and good self-lubrication. It can be used in oil lubrication and oil-free lubrication.