The sealing strip of motor car is made of EPDM, which has the following characteristics:

1. The density of low density and high filling ethylene propylene rubber is lower;

2. Aging resistance EPDM has excellent weather resistance, ozone resistance, heat resistance, acid and alkali resistance, water vapor resistance, color stability, electrical performance, oil filling property and room temperature fluidity. Ethylene propylene rubber products can be used for a long time at 120 ℃, and can be used briefly or intermittently at 150 - 200 ℃. The use temperature can be increased by adding appropriate antioxidant. EPDM crosslinked with peroxide can be used under harsh conditions. When the ozone concentration of EPDM is 50 pphm and the stretching time is 30%, the EPDM can reach 150 h without cracking.

3. Corrosion resistance Due to the lack of polarity and low unsaturation of ethylene propylene rubber, it has good resistance to various polar chemicals such as alcohol, acid, alkali, oxidant, refrigerant, detergent, animal and vegetable oil, ketone and grease;

4. Water vapor resistance EPDM has excellent water vapor resistance and is estimated to be superior to its heat resistance. In the 230 ℃ superheated steam, the appearance does not change after nearly 100 hours. However, under the same conditions, the appearance of fluorine rubber, silicon rubber, fluorine silicon rubber, butyl rubber, rubber and natural rubber has obviously deteriorated in a short time.

5. Elasticity Because ethylene propylene rubber has no polar substituents in its molecular structure, and its molecular cohesion energy is low, its molecular chain can maintain flexibility in a wide range, second only to natural rubber and cis polybutadiene rubber, and can still be maintained at low temperatures.