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PTFE Seals Excellent Properties Of

Yangzhong Tianyou Seals Co.,Ltd | Updated: Aug 29, 2017

PTFE Seals Excellent properties of

Pure ptfe seals have the following advantages:

1) low friction coefficient. The friction coefficient of pure polytetrafluoroethylene is the smallest in solid, only 0.02 ~ 0.10, so the frictional resistance is very low 2) and has high chemical stability. It can resist all kinds of acid and alkali corrosion. It's often called 'plastic king';

3) heat resistance performance is good, also is in commonly 80 ~ 200 ℃ under the condition of works;

4) the moisture absorption coefficient is small, and the water absorption rate is 0.01%.

Pure ptfe seals have the following disadvantages:

1) the linear expansion coefficient is larger, the pure ptfe during 20 ~ 60 ℃ linear expansion coefficient of alpha = 1 x 10-4 ℃ - 1; In 100 ~ 200 ℃, the alpha = 2 x 10-4 ℃ - 1;

2) poor thermal conductivity. Thermal conductivity of lambda = 0.47 W/(m, K);

3) not only has cold flow, but also can produce plastic deformation easily under high temperature and high pressure;

4) poor mechanical strength, low hardness and low elasticity. In order to make up the deficiency of pure polytetrafluoroethylene, and play its advantages, it is often used to add some filling materials to improve its performance. The commonly used filling materials and their functions are: the filling graphite and molybdenum disulphide can improve the thermal conductivity and wear resistance. Filling bronze, molybdenum and silver powder can improve mechanical strength and thermal conductivity. Fill glass fiber, asbestos, ceramic and so on can increase wear resistance and improve the anti-pressure ability, reduce the shrinkage rate. In conclusion, filling ptfe retains its original excellent properties and improves its strength, hardness and elasticity.

(a) high temperature resistant, use working temperature of 250 ℃.

(2) low temperature resistance - good mechanical toughness; Even if the temperature drops to 196 ℃, also can keep 5% elongation.