The characteristics of EPDM

1. Low density and high fillability

Ethylene-propylene rubber has a lower density of 0.87.In addition, it can be filled with a large amount of oil and filler, thus reducing the cost of rubber products, making up for the high price of epdm raw rubber, and for epdm with high Mooney value, the physical and mechanical energy after high filling is not significantly reduced.

2. Aging resistance

Ethylene propylene rubber has excellent weather resistance, ozone resistance, heat resistance, acid and alkali resistance, water vapor resistance, color stability, electrical properties, oil and room temperature fluidity.Ethylene propylene rubber products under 120 ℃ can be use for a long time, under the 150-200 ℃ can be temporary or intermittent use.Adding suitable anti - aging agent can increase its service temperature.Epdm crosslinked with peroxide can be used under harsh conditions.Epdm in the ozone concentration of 50pphm, stretch 30% of the conditions, can reach more than 150h without cracking.

3. Corrosion resistance

Due to the lack of polarity of ethylene propylene rubber, low degree of unsaturation, so on a variety of polar chemicals such as alcohol, acid, alkali, oxidant, refrigerant, detergent, animal and vegetable oil, ketone and fat have good resistance;However, it is less stable in aliphatic and aromatic solvents (such as gasoline, benzene, etc.) and mineral oils.The performance will also decrease under the long-term action of concentrated acid.In ISO/TO 7620, nearly 400 materials on the effects of corrosive gaseous and liquid chemicals on various rubber properties are collected, and grades 1-4 are specified TO indicate their effects. The influence of corrosive chemicals on rubber properties is as follows:

The effect of grade volume swelling rate /% hardness reduction on performance

1<10 <10 slight or no

2. 10-20 <20 is smaller

3 30-60 <30 medium

4 >60 >30 severe

4. Water vapor resistance

Ethylene-propylene rubber has excellent water vapor resistance and is estimated to be superior to its heat resistance.In the 230 ℃ heating steam, nearly 100 h after no change in appearance.Under the same conditions, fluorine rubber, silicone rubber, fluorine silicone rubber, butyl rubber, nitrile butadiene rubber and natural rubber experienced obvious deterioration in appearance after a short time.

5, resistance to hot water

Ethylene-propylene rubber also has good resistance to superheated water, but is closely related to all vulcanization systems.For sulfide two morphine TMTD, ethylene propylene rubber vulcanization system, in 125 ℃ hot water for 15 months later, the mechanical properties change little, volume expansion rate of only 0.3%.

6. Electrical performance

Ethylene-propylene rubber has excellent electrical insulation performance and corona resistance, electrical performance is better than or close to styrene butadiene rubber, chlorosulfonated polyethylene, polyethylene and crosslinked polyethylene.

7, elastic

Due to the non-polar substituents in the molecular structure of epdm, the molecular cohesion energy is low, and the molecular chain can maintain the flexibility in a wide range, second only to natural rubber and butadiene rubber, and can still maintain at low temperature.

8. Adhesiveness

Ethylene-propylene rubber due to the lack of molecular structure of active groups, low cohesion energy, and easy to spray rubber, self-viscosity and mutual viscosity is very poor.