design guide

Wear Resistant and Lubricated Compounds

There are a variety of techniques to enhance the wear resistance of a rubber component. A common technique includes the introduction of low friction fillers, such as PTFE, molybdenum disulfide or graphite into the compound during mixing. These wear resistant compounds have proven to provide longer life in applications involving frequent reciprocation.

A unique method used by Minnesota Rubber and Plastics to provide friction reduction is the addition of lubrication chemicals into the elastomer mixture. These chemicals modify the surface of the part to provide an "internally lubricated" compound which greatly reduces surface friction. (See table.) The mechanism of the lubricant does not affect the long-term physical properties of the rubber part. The internally lubricated compounds are designed for intermittent or slow cycling type applications. It is recommended that designs with long idle times make use of these compounds to assure minimum startup friction.

Coefficient of Friction Comparisons

Hardness
Shore A
Polymer Compound Type Coefficient of Friction
Static Dynamic
70 EPDM 559N STANDARD 0.57 0.64
560RJ LUBRICATED 0.18 0.17
90 EPDM 559GT STANDARD 0.55 0.54
561NA LUBRICATED 0.30 0.15
70 NBR 366Y STANDARD 1.10 1.02
366HA LUBRICATED 0.17 0.17
70 NBR 525K STANDARD 2.10 2.33
525EX LUBRICATED 0.15 0.09