I. Core Chemical Properties of EPDM Rubber Gaskets 

The molecular structure of EPDM rubber contains no polar groups, and its main chain consists of stable carbon-carbon single bonds, endowing it with unique chemical characteristics: 

1. Chemical Medium Resistance 

- **Acid and alkali corrosion resistance**: It exhibits good tolerance to dilute acids (e.g., sulfuric acid, hydrochloric acid), dilute alkalis (e.g., sodium hydroxide), and salt solutions, making it suitable as a seal in low-concentration chemical environments. 

- **Limited resistance to polar solvents**: It has poor tolerance to strong polar solvents such as ketones and esters, which may cause swelling or degradation. However, it shows strong resistance to non-polar solvents (e.g., petroleum ether, mineral oil). 

- **Water and steam resistance**: It has excellent water resistance and steam resistance, resisting aging even after long-term contact with hot water or saturated steam, making it suitable for sealing in humid and hot environments. 

2. High and Low Temperature Resistance  

- **Wide operating temperature range**: It can generally be used long-term at **-40℃~150℃**, with a short-term maximum temperature resistance of up to 170℃. It retains elasticity in low-temperature environments and is not prone to hardening or cracking at high temperatures. 

3. Aging and Weather Resistance 

- **Ozone and oxidation resistance**: Its molecular structure contains no double bonds (or only a small number of non-conjugated double bonds), giving it strong resistance to ozone, oxygen, and ultraviolet rays. It is not prone to aging phenomena such as cracking or hardening during outdoor exposure or long-term use. 

- **Climatic adaptability**: It maintains stable performance in natural environments with sunlight, rain, and alternating high and low temperatures, with a service life much longer than that of natural rubber or nitrile rubber. 

4. Physical and Mechanical Properties  

- **Elasticity and compression set**: It has good elasticity and resilience, with strong recovery ability after compression. The "compression set rate" after long-term compression is low (usually <25%), ensuring long-lasting sealing performance. 

- **Insulating properties**: It is an electrical insulating material with high volume resistivity, suitable as an insulating seal in electrical equipment. 

II. Typical Application Scenarios of EPDM Rubber Gaskets 

Based on the above properties, EPDM gaskets are widely used in the following scenarios: 

1. Plumbing and Pipeline Systems  

- Sealing flanges or joints in domestic tap water pipelines, hot water pipelines, and underfloor heating systems. Their water resistance and high-temperature steam resistance effectively prevent leakage. 

- Sealing municipal water supply and drainage pipelines, resisting impurities in water and mild chemical corrosion. 

2. HVAC (Heating, Ventilation, and Air Conditioning) and Refrigeration Equipment 

- Sealing interfaces in air conditioning units, cooling towers, and heat pump systems, adapting to alternating hot and cold environments and resisting condensation water corrosion. 

- Sealing gaskets for cold storage and refrigeration equipment, retaining elasticity at low temperatures to ensure thermal insulation. 

3. Automotive and Transportation  

- Sealing automotive cooling systems (water tanks, radiators) to withstand antifreeze and high-temperature coolant; window seals and door seals, utilizing weather resistance to resist outdoor aging. 

- Sealing air conditioning systems and ventilation pipelines in rail transit (subways, high-speed railways), adapting to vibration and temperature changes. 

4. Electrical and Electronic Equipment  

- Waterproof sealing gaskets for electrical control cabinets and distribution boxes, providing both insulation and moisture resistance. 

- Sealing interfaces for outdoor lighting fixtures and charging piles, resisting rain, ultraviolet rays, and ozone aging. 

5. Food and Medical Industries (Food-Grade EPDM)  

- Food-grade EPDM gaskets compliant with FDA (U.S. Food and Drug Administration) or LFGB (German Food Contact Materials Standard) can be used for sealing food processing equipment, beverage pipelines, and medical devices, as they are non-toxic and resistant to cleaning and disinfection. 

6. Industrial Equipment and Mild Chemical Corrosion Scenarios  

- Sealing flanges and valves in general industrial equipment, especially suitable for sealing non-strongly corrosive media (e.g., water, air, inert gases). 

- Sealing pipelines in sewage treatment equipment and agricultural irrigation systems, resisting mild acids, alkalis, and microbial environments. 

III. Advantages and Limitations of EPDM Rubber Gaskets  

### Advantages 

- Excellent weather resistance and aging resistance, with a long service life; 

- Strong adaptability to high and low temperatures, suitable for a wide range of scenarios; 

- Outstanding performance in water resistance, steam resistance, and dilute acid/alkali resistance; 

- Good elasticity, high sealing reliability, and low maintenance costs. 

### Limitations 

- Poor tolerance to strong polar solvents (e.g., acetone, ethyl acetate) and concentrated acids/alkalis, making it unsuitable for such environments; 

- Slightly lower wear resistance and tear strength than nitrile rubber or neoprene, not ideal for high-frequency friction or high-load sealing scenarios; 

- Higher cost than natural rubber but lower than specialty rubbers like fluororubber. 

IV. Selection Considerations  

- **Medium compatibility**: Confirm the type of chemical medium in the usage environment to avoid contact with strong polar solvents or concentrated acids/alkalis; 

- **Temperature range**: Select the appropriate grade of EPDM based on operating temperatures (e.g., high-temperature-specific grades can increase the temperature resistance limit); 

- **Food-grade requirements**: For contact with food or pharmaceuticals, choose EPDM materials certified for food contact to ensure non-toxicity and safety. 

In summary, EPDM rubber gaskets, with their comprehensive advantages of "weather resistance, temperature resistance, water resistance, and anti-aging properties", are an ideal choice in industrial and civil sealing fields, especially excelling in outdoor, humid-heat, or mild corrosion environments.