Rotary seal compound rubber compounds

Rotary seal compound with high nitrile rubber content (Table 10.5)... 

The rotary seal compound is sticky during mixing, but the O ring compound is not. The activator RCD 2098 is a zinc chloride/MBTS complex. Zinc diethyl dithiocarbamate and other activators containing zinc may also be used, but they are less effective. These polyurethanes have outstanding abrasion resistance, similar to neoprene in ozone and weather resistance, and comparable to nitrile rubbers in oil and fuel resistance. Heat aging is excellent up to 250°F (121°C), and the brittle point is —90°F (—68°C). 

Rotary sealing rubber compounds, as opposed to static O ring compounds, should most preferably have 80 shore A to 90 shore A hardness. Soft rubber compounds, if used for manufacture of these seals, will tend to drag the rotating shaft, wear out and be heated up, causing failure. 

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