Results of experimental investigation for a sealing unit containing small-sized collar made from fluoroplastic-4 are presented. In the course of experiments the collar's serviceability has been verified within a temperature range from -50°C to 200°C at working medium (liquids, gases) pressure of up to 700 kgf/cm. Dependences of both static and dynamic frictional forces versus collar delta pressure, temperature and velocity of the sealed part movement have been determined. The results obtained may be used for both static and dynamic analyses during phase of the sealing unit designing.