What is the reason of rubber seal aging

Rubber sealing ring is made of rubber material, so what is the reason for the aging of rubber sealing ring? In the production process of rubber sealing ring, due to the comprehensive effect of internal and external factors, the physical and chemical properties and mechanical properties of rubber gradually deteriorate, resulting in the loss of use value. This change is called rubber aging. On the surface, it is cracked, sticky, hardened, softened, powdered, discolored, moldy and so on. So, what are the specific factors?

A. Temperature

The increase of temperature leads to the cracking of the rubber material of the sealing ring, the chemical oxidation reaction and the acceleration of the rubber oxidation reaction.

B. Illumination

The shorter the light wave, the greater the energy. The destruction of rubber sealing ring is caused by ultraviolet radiation with high energy. In addition to the breaking and crosslinking of rubber molecular chain directly caused by ultraviolet radiation, the rubber of rubber sealing ring generates free radicals due to absorption of light energy, which initiates and accelerates the oxidation chain reaction process.

C. Oxygen

The free radical chain reaction between oxygen and rubber molecules occurs in rubber, and the molecular chain is broken or over crosslinked, which leads to the change of rubber sealing ring performance. Oxidation is one of the important reasons for rubber aging.

D. Ozone

The chemical active oxygen of ozone is much higher and more destructive. It also breaks the molecular chain, but the effect of ozone on rubber varies with the deformation of rubber sealing ring or not.

E. Humidity

The rubber sealing ring is easy to be damaged when it is soaked in water or wet air. This is because the water-soluble substances and water-soluble groups in the rubber are extracted and dissolved by water.

F. Mechanical stress

Under the repeated action of mechanical stress, the molecular chain of rubber sealing ring will break and produce free radicals, which will cause oxidation chain reaction and easily cause ozone cracking under the action of stress.