Choosing the right material is one of the most important steps in creating a successful molded rubber part. Each rubber compound has its own strengths, weaknesses, and ideal applications. The right choice can mean the difference between a part that lasts for years and one that fails under stress.

Below are some of the most commonly used materials in rubber molding and where each one excels.


EPDM (Ethylene Propylene Diene Monomer)

EPDM is one of the most versatile and widely used rubber materials. It offers excellent resistance to weather, ozone, water, and aging, making it a go-to choice for outdoor and automotive applications. It’s also resistant to many polar fluids like brake fluids and water-based solutions, though it’s not suitable for petroleum-based oils.

Best for: weather seals, gaskets, outdoor applications, and automotive components.


Nitrile (NBR, Buna-N)

Nitrile rubber is known for its outstanding resistance to oils, fuels, and other hydrocarbons. It’s strong, durable, and performs well in industrial and mechanical environments. Nitrile’s balance of toughness and affordability makes it one of the most common choices for oil-handling applications.

Best for: seals, O-rings, fuel system components, and oil-resistant parts.


Silicone (VMQ)

Silicone rubber stands out for its wide temperature range — remaining flexible in extreme cold and stable at very high heat. It also offers excellent resistance to weathering and aging, and it’s safe for use in food and medical applications thanks to its cleanliness and biocompatibility.

Best for: high- and low-temperature seals, medical devices, food-grade products, and electronics.


Viton® (FKM)

Viton is a high-performance fluoroelastomer prized for its chemical and heat resistance. It performs reliably in harsh environments with exposure to fuels, oils, and aggressive chemicals, even at elevated temperatures. It’s often used where longevity and performance are more important than cost.

Best for: aerospace, automotive, and chemical-processing applications.


Neoprene (CR)

Neoprene offers good all-around performance — balancing oil resistance, weathering resistance, and mechanical strength. It’s often chosen for applications that need flexibility and durability across a variety of conditions.

Best for: industrial hoses, vibration mounts, and general-purpose seals.


Natural Rubber (NR)

Natural rubber provides excellent tensile strength, tear resistance, and elasticity. It performs well in dynamic applications where flexibility and resilience are key, though it’s less resistant to oils and ozone than synthetic options.

Best for: vibration dampening, shock absorption, and flexible mechanical components.


Primo Rubber Co. — Your Material Partner

At Primo Rubber Co., we work with a wide range of rubber compounds to meet the needs of diverse industries. Whether your part requires oil resistance, heat tolerance, flexibility, or FDA compliance, our team can recommend and mold the right material for your application. With years of experience in rubber injection molding, we ensure that every project combines the right material with precision manufacturing for the best possible results.

From EPDM to Viton — Primo Rubber Co. is your trusted partner for custom molded rubber parts. Contact Primo Rubber Co. today to learn more about our custom rubber molding capabilities and material options.