This invention provides a rod sealing system comprising a buffering, a rod seal, and a dust seal provided in that order from a fluid pressure side toward an external side between annular gaps between two reciprocating members. The buffering is formed of a thermoplastic polyurethane molded product that has been produced by reacting (A) a high-molecular weight polycarbonate diol having a number average molecular weight Mn of 500 to 6000, (B) an aromatic diisocyanate, and (C) a low-molecular weight diol as a chain elongation agent at an NCO/OH ratio of 0.95 to 1.20 followed by heat treatment under such conditions that the hard phase glass transition point (Tg) as measured by differential scanning calorimetry is 170°C or above, preferably 170 to 230°C, and the endothermic peak area (H) of Tg is not less than 5 J/g. The buffering formed of this thermoplastic polyurethane molded product is excellent, for example, in heat resistance, particularly heat resistance enough to withstand a service environment up to 120°C, compression permanent deformation resistance, and eccentricity following property.
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