The aging of rubber seals is usually caused by mechanical forces, oxidation and ozone oxidation. Generally speaking, aging will make rubber seals brittle, accelerate the propagation of fatigue cracks, reduce critical fracture energy and shorten their service life. The aging process of rubber sealing ring mainly includes the following aspects:

1. Mechanical cracking reaction occurs under the action of mechanical force

Due to the viscosity of the polymer, the relaxation (relaxation) process of the rubber in the deformation cycle has not been completed, and the residual stress of the rubber seal continues to increase in the next deformation cycle. When the stress gradient is large, it will lead to the direct rupture of the rubber molecular chain and the formation of free (radical) groups, leading to oxidation chain reactions and aging of the rubber under the action of oxygen.

2. Mechanical stress will weaken the valence force of the atoms in the rubber molecular chain, thereby reducing the activation (chemical) energy of the oxidation reaction. The reduction of oxidative activation (chemical) energy makes the oxidative cracking of the rubber chain easier and faster.

3. The internal heating of the rubber seal accelerates the oxidation reaction

When the rubber sealing ring is repeatedly deformed, it will cause internal friction, thereby generating internal heat of the rubber, and further accelerating the oxidation chain reaction and aging of the rubber.

4. During the aging process of the periodic deformation of the rubber seal ring, especially at high temperatures, ozone rupture will occur.

Therefore, the fatigue aging of rubber seals is actually the result of mechanical force, temperature, oxygen, ozone and other factors. It can be seen that, in the production design of rubber seals, it is necessary for rubber product manufacturers to improve their anti-aging (aging) performance.