Elastomers

Nitrile (NBR, Buna-N)

Nitrile rubber, a popular choice for industrial seals, combines cost-effectiveness with robust performance. This elastomer is made from acrylonitrile (ACN) and butadiene and offers excellent oil and fuel resistance. ACN content can range from 18-50%, typically around 34%, balancing chemical resistance and low-temperature flexibility.

  • 70 Durometer O-Ring Temperature Range: -30ºC to 121ºC (-22ºF to 250ºF)
  • 90 Durometer O-Ring Temperature Range: -25ºC to 121ºC (-13ºF to 250ºF)
  • Cord Stock Temperature Range: -40ºC to 100ºC (-40ºF to 212ºF)

Nitrile is sulfur-cured to enhance thermal stability and compression resistance. It is known for high tensile strength, good elongation, and excellent compression set properties, making it durable and flexible for diverse sealing environments.

  • Primary Uses: It is ideal for various applications, including automotive fuel systems, oil and gas production, and agriculture industries.
  • Compatibility: It is ideal for use with mineral oils, diluted salts, and moderate water exposure. It is unsuitable for concentrated acids, alkalis, high-temperature steam, or ketones.

Viton (FKM, Fluoroelastomer)

Viton® (FKM, Fluoroelastomer) is a high-performance rubber known for its outstanding resistance to extreme temperatures, chemicals, and weathering. While often mentioned alongside FKM, Viton® is a specific brand of fluoroelastomer produced by Chemours and distinguished by its high quality and performance standards. FKM refers to the broader category of fluoroelastomers defined by ASTM International Standards.

  • O-Ring Temperature Range: -25ºC to 250ºC (-13ºF to 482ºF)
  • Brown Cord Stock Temperature Range: -18ºC to 205ºC (0ºF to 401ºF) static, -6ºC to 205ºC (21ºF to 401ºF) dynamic
  • Black Cord Stock Temperature Range: -32ºC to 204ºC (-25ºF to 399ºF) static, -17ºC to 204ºC (1ºF to 399ºF) dynamic

Viton® o-rings are mechanically robust, offering high tensile strength and moderate elongation, which results in a flexible seal that is highly resistant to tension and compression. These properties ensure a low compression set, meaning Viton® maintains its shape and effectiveness under pressure.

  • Primary Uses: Viton® is widely favored for its durability and performance in the chemical processing, automotive, oil and gas, and energy generation sectors.
  • Compatibility: It is excellent with petroleum products, mineral and silicone oils, and high vacuum environments. It should not be used with ketones, low molecular weight esters, or phosphate ester-based hydraulic fluids.

Silicone (VMQ)

Silicone elastomers are notable for their excellent thermal stability, flexibility at low temperatures, and resistance to various chemicals and environmental conditions. This synthetic rubber is FDA-compliant, non-toxic, and non-reactive, making it suitable for direct contact with food, drink, or medications.

  • O-Ring Temperature Range: -55ºC to 200ºC (-67ºF to 392ºF)
  • Cord Stock Temperature Range: -60ºC to 225ºC (-76ºF to 437ºF)

Silicone’s exceptional mechanical properties include moderate tensile strength, excellent elongation, and a low compression set, ensuring durability and flexibility across diverse applications. Its bio-inert nature makes it safe for medical devices and implants, avoiding adverse biological responses.

  • Primary Uses: Widely used in automotive, electronic, medical, pharmaceutical, and food and beverage industries.
  • Compatibility: It is ideal for engine and transmission oil, diluted sat solutions, moderate water, dry heat, ozone, and weather. It is not recommended for concentrated acids and alkalis, steam over 210ºC (248ºF), petroleum oils and fuels, and ketones.

EPDM (Ethylene Propylene Diene Monomer)

EPDM rubber is a resilient synthetic elastomer known for its superior resistance to harsh weather conditions, UV radiation, and ozone. Due to its low-temperature flexibility, it is also highly valued for outdoor applications. Peroxide-cured EPDM offers enhanced resistance to high temperatures and reduced compression set.

  • O-Ring Temperature Range: -55ºC to 125ºC (-67ºF to 257ºF)
  • Cord Stock Temperature Range: -40ºC to 121ºC (-40ºF to 250ºF)

EPDM’s excellent mechanical properties include good tensile strength and elongation at break, allowing it to resist tears and maintain flexibility under mechanical pressure. Its high dielectric strength makes it an effective insulator, suitable for various electrical applications.

  • Primary Uses: Commonly used in the automotive, water treatment, and oil & gas industries due to their durability and reliability.
  • Compatibility: It is ideal for use with alcohols, ketones, dilute acids/alkalis, silicone oils/greases, steam up to 400ºF, water, phosphate ester-based hydraulic fluids, ozone, and aging. Avoid use with aliphatic/aromatic hydrocarbons, di-ester based lubricants, halogenated solvents, and petroleum-based oils/greases.

AFLAS® (TFE/P)

Developed by Asahi Glass Co., AFLAS® elastomers are copolymers of tetrafluoroethylene (TFE) and propylene (FEPM). They offer unique properties suitable for the most demanding environments, including exceptional chemical resistance and dynamic sealing performance in high-pressure systems, rapid temperature changes, and aggressive chemical exposures.

  • O-Ring Temperature Range: -10ºC to 220ºC (14ºF to 428ºF)
  • Cord Stock Temperature Range: -10ºC to 204ºC (14ºF to 400ºF)

AFLAS® is known for its high tensile strength, good elongation, and low compression set, which allow it to withstand stretching, pulling, and compression. This makes it highly effective in maintaining seal integrity under harsh conditions.

  • Primary Uses: It is ideal for demanding sectors such as automotive, oil and gas, chemical processing, and pharmaceuticals.
  • Compatibility: Can be used with petroleum fluids, brake fluids, bases, phosphate esters, amines, engine oils, steam, hot water, and pulp and paper liquids. Avoid using it with aromatic fuels, ketones, and chlorinated hydrocarbons.

Comprehensive Comparison of Elastomer Properties

This table consolidates key mechanical properties such as tensile strength, elongation, and compression set across our five key elastomers. It is a reference to easily compare each material’s physical capabilities and limitations, facilitating a deeper understanding of how each elastomer behaves under stress and strain, which is critical for engineering and application-specific decisions.

Material Tensile Strength Elongation Compression Set Chemical Compatibility Low. Temp. Performance High Temp. Perforamnce Relative Cost
Nitrile Excellent Excellent Excellent Moderate Good Moderate $
Viton® Excellent Moderate Good Excellent Good Excellent $$$
Silicone Moderate Excellent Excellent Good Excellent Excellent $$
EPDM Good Good Good Good Excellent Moderate $
AFLAS® Excellent Good Moderate Excellent Moderate Excellent $$$

Operational Temperature Ranges of Elastomeric Compounds

This graph illustrates our compounds’ static operational temperature ranges, showcasing their performance from the lowest to the highest temperatures they can withstand. This visual aid highlights each elastomer’s thermal adaptability, which is crucial for selecting a material that will maintain its integrity and functionality across the expected temperature spectrum of its application environment.

Chemical Compatibility of Elastomers

This table outlines the chemical resistance profiles of our five key elastomers against a selection of common industrial chemicals and substances. By delineating which materials are resistant to specific chemicals, this guide assists in identifying the most suitable elastomer for environments that involve exposure to potentially corrosive or reactive substances, ensuring the durability and reliability of seals and components.

Chemical Type Nitrile Viton Silicone EPDM AFLAS
Petroleum Oils and Fuels Excellent Excellent Poor Poor Good
Water and Steam Good Good Excellent Excellent Excellent
Alcohols Good Excellent Excellent Excellent Excellent
Acids (Dilute) Moderate Excellent Good Excellent Excellent
Alkalis (Dilute) Good Good Good Excellent Excellent
Ketones Poor Poor Excellent Moderate Good
Silicone Oils and Greases Moderate Excellent Excellent Good Excellent
Aromatic Hydrocarbons Poor Excellent Poor Poor Good
Chlorinated Solvents Poor Excellent Poor Poor Excellent
Brake Fluids Moderate Excellent Poor Good Excellent
Phosphate Ester Hydraulic Fluids Poor Poor Good Excellent Good
Scroll to Top