The function of rubber seals is to prevent leakage, and effective prevention of leakage is the primary requirement for seals. Tightness reflects the level of control over leakage. For motion seals, friction is an important factor related to the quality of motion. But sealing and friction always restrict each other. Generally speaking, improving the sealing performance will bring about an increase in friction, and the increase in friction will directly lead to a decrease in movement ability and quality; and friction will accelerate the wear of the seal. Friction may also become the main content of the low-voltage system load. The durability of the seal reflects the highest pressure of the working medium that can be sealed, and is an important indicator of hydropneumatic sealing.

The basic requirements for sealing can be summarized as:

1) Sealing performance.

2) Friction performance.

3) Pressure resistance.

4) Life.

5) Installation performance.

6) Economy.　　

The above-mentioned sealing performance, friction performance of rubber seals, and pressure resistance are independent performances. The combination of these three properties results in the comprehensive performance of the seal; the retention time of the comprehensive performance is the life of the seal; the actual rubber seal design The installation performance and economy should also be regarded as an important index. The comprehensive performance of rubber seals is not only related to the performance of the seal itself, but also related to a number of use conditions of the seal. Therefore, to examine the sealing performance, it is necessary to look at the performance of the seal or the seal combination itself, which is called the monomer performance. It also depends on the actual sealing performance after the seal is installed in the hydraulic and pneumatic components, which is called the actual sealing performance.