Rod sealing system

摘要: In a rod sealing system, which comprises buffer ring, seal, and dust provided successively in this order from fluid hydraulic side toward the outside an annular clearance between two members reciprocating motion, ring is made up of thermoplastic polyurethane molding product obtained by subjecting prepared reaction (A) high molecular weight polycarbonatediol having number average Mn 500-6,000, (B) aromatic diisocyanate, (C) low diol as chain elongation agent NCO/OH ratio 0.95-1.20, to heat treatment under conditions that glass transition point (Tg) hard phases becomes 170° C. or higher, preferably 170-230° C., endothermic peak area (ΔH) at Tg 5 J/g more, differential scanning calorimetry. The has distinguished resistance capable withstanding service environmental temperature, particularly maximum 120° compression set characteristics, follow-up eccentricity, etc.