Effect of Humidity Upon Polyacrylate Radial Lip Seal Parameters

Some elastomeric materials used in the manufacture of radial lip seals absorb moisture. This moisture tends to soften the material and cause the hardness, radial load and lip opening pressure to decrease. When exposed to a dry atmosphere, some materials will release the moisture. The radial load, hardness and lip opening pressure will then increase.

A study was performed to determine the effect of moisture on seal physical properties, functional life and cold temperature performance. The seals were made from a polyacrylate material.

Polyacrylates absorb and release water readily. It was found that variations in environmental conditions did not affect seal function. The physical properties of these seals varied significantly with humidity. Seals made from polyacrylate materials should be preconditioned at a known humidity and temperature level before radial load, lip opening pressure and hardness measurements are made. This procedure will help guarantee consistency when conducting quality control tests.