How to choose the appropriate rubber seal material?

How to choose the appropriate rubber seal material?

The selection of rubber seal material mainly depends on the four core conditions of the medium used, temperature, pressure, and working environment, combined with comprehensive cost judgment.

1. First, look at the contact medium (most importantly)

Water, air, weak acids and bases

Priority selection: EPDM (Ethylene Propylene Diene Monomer)

Good water resistance, weather resistance, ozone resistance, and cost-effectiveness.

Oil, fuel, lubricating oil

Priority selection: NBR (nitrile rubber)

Commonly used, oil resistant, and reasonably priced, we are an honest merchant in hydraulic and automotive parts.

Strong acid, strong alkali, strong solvent, high-temperature oil

Priority selection: FKM/Viton (fluororubber)

Strong chemical resistance and high temperature resistance (based on actual reports), but high price.

Food diagnosis and treatment, clean environment, and universal use of high and low temperatures

Priority selection: Silicone

Poison detection is odorless, resistant to high and low temperatures, but not resistant to oil.

Strong wear and tear, dust, and harsh outdoor environments

Priority selection: PU (polyurethane)

Wear resistant (based on actual reports), pressure resistant, commonly used in hydraulic cylinders.

2. Check the working temperature range again

-40 ℃~120 ℃: NBR nitrile rubber

-50 ℃~150 ℃: EPDM (Ethylene Propylene Diene Monomer)

-60 ℃~230 ℃: FKM fluororubber

-60 ℃~200 ℃: Silicone Silicone

-30 ℃~80 ℃: NR natural growth rubber (generally not used for sealing)

Exceeding the temperature range can directly lead to hardening, softening, oil leakage, and failure.

3. Observe stress and exercise patterns

Static seal (non moving)

NBR、EPDM、 Silicone is acceptable.

Dynamic seal (reciprocating/rotating)

Priority: NBR, PU, FKM

Wear resistant (based on actual reports) and strong tear resistance.

High pressure working condition

Priority: PU, FKM, to avoid ordinary rubber being extruded.

4. Check the environmental conditions

Outdoor, sun exposure, rainwater

Required: EPDM, ozone resistant and aging resistant.

Low temperature and cold regions

Selection: Silicone, Low Soft and Tough NBR

Food/drinking water contact

Required: grade silicone EPDM

5. Formula for selecting appropriate speed (easy to remember and use)

Choose NBR when encountering oil

Choose EPDM when encountering water

FKM is selected for high temperature corrosion

Choose silicone for food cleanliness

Wear resistant (based on actual reports), high-pressure PU selection