The density of ethylene propylene rubber is a lower rubber with a density of 0.87. In addition, the oil can be filled in a large amount and the filler is added, thereby reducing the cost of the rubber product, making up for the disadvantage of high ethylene rubber rubber price, and for the high Mooney value of ethylene propylene rubber, the physical mechanical energy can be reduced after high filling. Not big.
Ethylene-propylene rubber has excellent weather resistance, ozone resistance, heat resistance, acid and alkali resistance, water vapor resistance, color stability, electrical properties, oil filling and room temperature fluidity. Ethylene-propylene rubber products can be used for a long time at 120 ° C, and can be used temporarily or intermittently at 150-200 ° C. Adding a suitable anti-aging agent can increase its use temperature. The peroxide-crosslinked EPDM rubber can be used under severe conditions. EPDM rubber can be cracked for more than 150h under the conditions of ozone concentration of 50pphm and stretching of 30%.
Due to its lack of polarity and low unsaturation, ethylene-propylene rubber has good resistance to various polar chemicals such as alcohols, acids, alkalis, oxidants, refrigerants, detergents, animal and vegetable oils, ketones and fats. However, it is less stable in aliphatic and aromatic solvents (such as gasoline, benzene, etc.) and mineral oil. The performance also decreases under the long-term effect of concentrated acid. In ISO/TO7620, there are nearly 400 kinds of information on the effects of corrosive gaseous and liquid chemicals on various rubber properties, and 1-4 grades are indicated.The effect of corrosive chemicals on rubber properties:
Grade Volume Swelling rate / % hardness reduction value Impact on performance
1<10<10 slight or no
Water vapor resistant
Ethylene-propylene rubber has excellent water vapor resistance and is superior to its heat resistance. In the superheated steam at 230 ° C, there was no change in appearance after nearly 100 h. Fluorine rubber, silicone rubber, fluorosilicone rubber, butyl rubber, nitrile rubber, and natural rubber experienced significant deterioration in appearance over a short period of time under the same conditions.
Resistant to hot water
Ethylene-propylene rubber is also resistant to superheating, but is closely related to all vulcanization systems. Ethylene-propylene rubber with dimorpholine disulfide and TMTD as vulcanization system, after soaking for 15 months in 125 ° C superheated water, the mechanical properties changed very little, and the volume expansion rate was only 0.3%.
Ethylene-propylene rubber has excellent electrical insulation properties and corona resistance, and its electrical properties are superior to or close to styrene-butadiene rubber, chlorosulfonated polyethylene, polyethylene and cross-linked polyethylene.
Since there is no polar substituent in the molecular structure of ethylene propylene rubber, the molecular cohesive energy is low, and the molecular chain can maintain flexibility in a wide range, which is second only to natural commercial and butadiene rubber, and can be maintained at low temperatures.
Ethylene-propylene rubber lacks active groups due to its molecular structure, low cohesive energy, and the rubber is easy to bloom, and its self-adhesiveness and mutual viscosity are poor.