EPDM stands for ethylene propylene diene monomer. Ethylene and propylene are both byproducts of oil, making this rubber synthetic. It is a type of rubber used in many outdoor applications, including roofs, weather seals, O-rings, and countless others. EPDM is known for being extremely resistant to the ozone, UV light, and harsh weathering. This rubber has a shelf life of up to 15 years.
The durability of EPDM is tried and true. For this reason, EPDM to this day is still used on roof tops worldwide. EPDM also has a fairly good low temperature rating, most EPDM’s stay flexible down to -50 degrees Celsius. When a rubber is no longer flexible it is known as the glass transition point of the rubber. This point is when the rubber is not flexible and has a leather like feel.
Another benefit of EPDM is the ozone resistance it inherently has. The common test method to test for ozone resistance is ASTM D1171. This test method outlines testing for ozone for different rubbers. It is a good thing to keep in mind albeit that EPDM can be compounded to be flame retardant but should not be thought of as flame retardant is any way, this comes from EPDM’s inherent nature. Ethylene and propylene are both derivatives of hydrocarbons, thus EPDM can be burnt fairly easily.
EPDM can be formulated to meet many specifications, the ASTM D1418 designates EPDM as EPM. ASTM D2000 commonly designates EPDM as BA or CA, normally with a durometer and tensile requirement following. EPDM can be manufactured to meet many different standards, including AMS-3260, MIL-R-3065, NAS-1613, MIL-R-900 and others. The compliance with standards normally starts with the formulation of the rubber compound. The rubber compound is manufactured with different additives, fillers, and elastomers to meet the requirement set forth by the standard. After this the rubber is vulcanized, which is the process of the rubber crosslinking. The reason this term is used is when rubber is vulcanized it is put under enormous heat and pressure to provide an environment conducive for crosslinking. Rubber vulcanization was first recorded in 1846 by Charles Goodyear. This process provides the rubber its elasticity and strength.
Normally EPDM comes in black. This black comes from the carbon particles that are used as a filler to toughen the rubber.
EPDM can also be formulated to meet certain electrical and conductivity requirements. EPDM can be formulated to provide conductive properties. EPDM can also be provided in many forms, including but not limited to molded O-rings, die cut parts, molded shapes, extruded, strips, waterjet cut parts, and other forms. Normal thicknesses EPDM comes in are .020”, .031”, .062”, .125”, .250” and .500”. Because of NEDC’s unique capabilities NEDC can provide custom thicknesses all the way up to 1.000”.
EPDM can also be provided in different durometers, with varying tensile strengths. The durometers that EPDM can be provided in vary from 30-90 Shore A.