Choosing the right rubber compound is one of the most important steps in creating a reliable, high-performing molded part. Each material has its strengths and weaknesses depending on the environment, temperature, and chemical exposure. Among the most common options are EPDM, Nitrile (Buna-N), and Silicone. Here’s how they compare — and how to choose the right one for your application.

EPDM (Ethylene Propylene Diene Monomer)

EPDM is known for its excellent resistance to weathering, ozone, water, and UV exposure. It performs exceptionally well outdoors and in applications exposed to the elements. It also resists many polar substances, including alcohols, brake fluids, and phosphate esters.

Best For:

  • Outdoor seals and gaskets
  • HVAC components
  • Automotive weatherstripping
  • Water system parts and hoses

Limitations:

EPDM doesn’t handle petroleum oils or hydrocarbons well. For applications involving fuel, lubricants, or oil contact, another material (like Nitrile) is a better fit.

Nitrile (Buna-N)

Nitrile rubber is the go-to choice for oil-resistant applications. It has excellent resistance to fuels, lubricants, and many hydraulic fluids, making it a popular choice in industrial and automotive environments. It also offers good tensile strength and abrasion resistance.

Best For:

  • Fuel and oil seals
  • Industrial hoses and grommets
  • Automotive gaskets and O-rings
  • Hydraulic and pneumatic seals

Limitations:

Nitrile doesn’t perform as well in extreme weather or UV exposure. It can also stiffen in very cold temperatures, so outdoor flexibility can be an issue in freezing environments.

Silicone

Silicone rubber excels in temperature stability and flexibility across a wide range — typically from -75°F to +450°F. It’s also highly inert, non-reactive, and available in FDA-approved grades, making it a favorite in medical, food, and electronics applications. Silicone maintains softness and elasticity even under heat and compression.

Best For:

  • Food-grade and medical products
  • High-temperature seals and gaskets
  • Electronics and lighting components
  • Environments requiring chemical or ozone resistance

Limitations:

Silicone is not as strong as Nitrile or EPDM in tear or abrasion resistance, and it can be more costly. It’s also less resistant to fuels and oils.

Choosing the Right Rubber for Your Project

Selecting the right compound means understanding your environment:

  • Exposure to oil or fuel? → Go with Nitrile.
  • Outdoor or weather-exposed? → Choose EPDM.
  • High temperature or FDA compliance? → Silicone is ideal.

Each material has trade-offs, and the best choice often depends on balancing performance, durability, and cost.

Primo Rubber Co. Can Help You Choose the Perfect Material

At Primo Rubber Co., we work with a wide variety of rubber compounds — including EPDM, Nitrile, Silicone, and more — to ensure every part meets your performance requirements. Our experience in material selection and molding allows us to guide customers toward the best rubber for their unique application, from prototypes to full-scale production. Contact Primo Rubber Co. today to learn more about our custom rubber molding capabilities and material options.