When it comes to rubber moulding, one of the most critical — yet often overlooked — decisions is choosing the right polymer. At Wye Valley, we’ve spent decades helping clients across automotive, electronics, marine and industrial sectors select materials that meet their performance, durability and compliance needs. Not all rubbers are created equal — and the wrong choice can lead to costly failures down the line.

This guide explores the most common rubber polymers we work with — EPDM, NBR and Silicone — and how to match each to the right application.

Best for: Oil, fuel and chemical-resistant applications

NBR, often called nitrile rubber, is the go-to polymer for environments exposed to petroleum-based oils and fuels. Its chemical resistance and mechanical strength make it a staple in industrial and automotive settings.

Typical Uses:

• Fuel system seals and gaskets
• Hydraulic hoses and O-rings
• Oil-handling machinery components

Advantages:

• Excellent oil and fuel resistance
• Good tensile strength and abrasion resistance
• Performs well between -30 °C and +100 °C

Limitations:

• Limited resistance to ozone, sunlight, and weathering

For components exposed to lubricants or hydrocarbons, Wye Valley’s nitrile mouldings provide a dependable and long-lasting solution.

Best for: High-temperature, hygienic, and electrical applications

Silicone stands out for its ability to withstand extreme temperatures — from -60 °C to +200 °C — without losing flexibility or integrity. It’s also biocompatible and inert, making it suitable for medical, food-grade, and electronic applications.

Typical Uses:

• Oven and appliance seals
• Medical and pharmaceutical components
• Electrical insulation parts

Advantages:

• Exceptional temperature stability
• Resistant to ozone, weathering and aging
• Non-toxic and suitable for FDA-approved applications

Limitations:

• Lower tear and abrasion resistance
• Not ideal for high-pressure dynamic sealing

At Wye Valley, silicone is a popular choice for precision-moulded parts in demanding environments such as medical devices or high-heat systems.

Selecting the right rubber polymer is a balance of environmental, mechanical and chemical factors. A seal that performs perfectly indoors could fail outdoors, and a material that resists oil may degrade under ozone.

At Wye Valley, we assess your application’s full lifecycle, from exposure conditions to compliance requirements, and recommend the most cost-effective, high-performance solution. Our in-house moulding capabilities, material expertise and ISO 9001:2015-certified quality systems ensure every component is right the first time.

The right polymer makes all the difference between a reliable, long-lasting component and an early-life failure. Whether your project demands resistance to oil, heat, or the elements, Wye Valley’s expert team can guide you through the selection process and manufacture bespoke rubber mouldings that perform — and last.