Oil and heat resistance characteristics (described as O&HR on belts) are traditional application requirements for oil and heat resistance of belts. Although they are defined in RMA standards, in fact, this description is ambiguous. Oil and heat resistance are actually two different requirements of belts that should be distinguished.
Oil resistance: Occasional splashing of oil or grease on a belt usually does not have too much adverse effect on a regular belt. However, oil resistant belts do not deteriorate quickly as long as the oil or grease is within a reasonable range. A large amount of oil or grease on any belt can cause slippage and heat generation. Excessive oil contamination from petroleum products can cause rubber expansion and a decrease in the adhesive strength of rubber components, leading to belt breakage.
Heat resistance: No standard has a well-defined temperature limit range to ensure satisfactory performance, however, a suitable application belt typically requires an ambient temperature between -35 ℃ and+60 ℃. The material and structure of the belt determine the relative range and duration of heat resistance, which are represented as good and very good in the table below.
Ozone resistance characteristics
The ozone resistance of a belt is its ability to resist chemical corrosion in an ozone environment, as ozone can cause chemical bonding and decomposition, and the failure mode is cracking. The degradation of rubber mainly depends on the concentration of ozone and the frequency of exposure. When the belt is compressed, the degradation of rubber caused by ozone will increase. In theory, belts with larger cross-sections suffer more degradation than those with smaller cross-sections when bent on a pulley, represented as good and very good in the table below.
Antistatic properties
In some standards (ISO, RMA), there are specific descriptions for the conductivity and testing of belts. In some hazardous environments, certain protection measures need to be recommended, such as ensuring that the entire ground system is protected from sudden static electricity discharge, and a conductive brush or similar device can also release static electricity around the belt.