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NR (Natural Rubber)
• A general purpose rubber with the optimum balance of physical properties essential for high performance engineering applications.
• The working temperature range is considered to be -50°C/ -70°C to +120°C.
• Long fatigue life, first choice for spring applications.
• Has high strength without the need for reinforcing fillers.
• Can be compounded to give a wide range of hardness.
• Good low temperature flexibility.
• Poor resistance to oils and solvents.
• Requires protection against oxidisation, ozone and heat.
NBR (Nitrile-butadiene Rubber)
• NBR is the most widely used elastomer in the seal industry today.
• Good resistance to low temperature.
• NBR is often necessary to sacrifice some high temperature resistance.
• The working temperature range is considered to be -35°C to +120°C (-30°F to +250°F).
• Good tear, and abrasion resistance.
• NBR resists oil-based hydraulic fluids, fats, animal and vegetable oils, flame retardant liquids, grease, water, and air.
• Special low-temperature compounds are available for mineral oil-based fluids.
• Poor resistance to ozone, sunlight, or weather. They should not be stored near electric motors or other ozone generating equipment.
• By CR, Hypalon, or PVC blending, the NBR can meet a more specified range of physical or chemical requirements.
NBR+PVC
• PVC resins are blended with NBR to provide increased resistance to ozone and abrasion.
• The PVC also provides a significant improvement in solvent resistance, yet maintains similar chemical and physical properties of NBR.
HNBR (Hydrogenated Nitrile Butadiene Rubber)
• HNBR has excellent resistance to common automotive fluids (e.g., engine oil, coolant, fuel, etc.) and many industrial chemicals.
• The working temperature range is considered to be -40°C to +165°C.
• Good resistance to long-term exposure to heat, oil, and chemicals. Also good with aging resistance and low temperature resistance.
• The automotive market is the largest consumer, using HNBR for a host of dynamic and static seals, hoses, and belts.
• Disadvantage: expensive.
CR (Chloroprene Rubber, Neoprene)
• CR was the earliest synthetic rubbers used to produce seals.
• CR has good aging characteristics in ozone and weather environments, along with abrasion and flex cracking resistance.
• CR is not effective in aromatic and oxygenated solvent environments.
• The working temperature range is considered to be -40°C to +110°C.(-40°F to +230°F) But for short working periods it will take even 120°C.
• Good gasoline resistance.
EPM, EPDM (Ethylene Propylene Rubber)
• EPM/EPDM has a temperature range of -50°C to +120°/150°C (-60°F to +250°/300°F), depending on the curing system.
• It has a great acceptance in the sealing world because of its excellent resistance to heat, water and steam, alkali, mild acidic and oxygenated solvents, ozone, and sunlight.
• EPM/EPDM compounds are not recommended for gasoline, petroleum oil and grease, and hydrocarbon environments.
• Good resistance to brake fluid.
IR (Isoprene Rubber)
• Very similar properties to natural rubber but more difficult to process.
• The working temperature range is considered to be -50°C/ -70°C to +120°C.
• Electrical properties better than NR.
IIR (Butyl)
• Butyl has excellent resistance to phosphate ester fluids.
• It has an inferior high temperature limit when compared to EPM.
• The temperature service range for this material is -55°C to +105°C (-65°F to +225°F).
• Good ozone, weather environments, abrasion, chemical, and cracking resistance.
• Excellent air Impermeability.
• Poor gasoline and hydrocarbon resistance.
SBR (Styrene-butadiene Rubber)
• SBR must be compounded with reinforcing fillers for high strength and then has physical and chemical properties similar to NR.
• It is not suitable for springs but has used widely for vehicle tyres where it is generally oil extended.
• Excellent abrasion resistance.
• The working temperature range is considered to be -50°C to +110°C (-65°F to +225°F).
BR (Butadiene Rubber)
• Good temperature flexibility and high abrasion resistance under severe weather conditions.
• Main use in in manufacture of tyres.
• The working temperature range is considered to be -73°C to +120°C.
• Used in blends with SBR and NR.
• Poor processing properties and poor tear properties.
VMQ (Silicone)
• Moderate physical properties but are retained at high or low temperatures.
• Good electrical properties and good ozone resistance.
• The working temperature range is considered to be -50°C (-58°F) to +232°C (+450°F).
• PMQ, PVMQ have even lower low-temperature resistance (-73°C~-90°C).
• low tear strength and poor abrasion resistance.
• Poor oil, and poor chemical resistance.
FVMQ (Fluoro-silicone)
• Fluorosilicone combines the good high- and low-temperature properties of silicone with limited fuel and oil resistance.
• FVMQ provide a much wider operational temperature range than Fluorocarbon rubbers.
• The working temperature range is considered to be -73°C (-100°F) to 200°C (390°F).
• FVMQ O-rings may also be exposed to petroleum based oils and/or hydrocarbon fuels.
• Due to relatively low tear strength, high friction and limited abrasion resistance of these materials, they are generally recommended for static applications only.
• FVMQ with high tear strength are also available. Some of these compounds exhibit improved resistance to compression set.
• Disadvantage: too expensive.
FKM, FPM (Viton, Fluorel)
• FKM O-rings should be considered for use in aircraft, automobile and other mechanical devices requiring maximum resistance to elevated temperatures and to many fluids.
• FKM used in applications to resist harsh chemical and ozone attack.
• The working temperature range is considered to be -26°C to +205°/230°C (-15°F to +400°/440°F). But for short working periods it will take even higher temperatures.
• FKM resist mineral oils and greases, aliphatic, aromatic and also special chlorinated hydrocarbons, petrol, diesel fuels, silicone oils and greases.
• Disadvantage: too expensive. Especially perfluoroelastomer(FFKM).
ACM, ANM, AEM (Alkyl Acrylate Coplolymer)
• Good resistance at normal and elevated temperatures to oil and oxygen.
• Excellent ozone and and weathering resistance.
• The working temperature range is considered to be -0°C to +150°C. But for short working periods it will take even to 180°C.
• Poor water, moist heat, and low-temperature resistance.
• AEM (Ethylene Acrylate Rubber), Cold flexibility between -29°C and -40°C (-20°F and -40°F)
ECO, CO (Epichlorohydrin)
• ECO compounds are noted for their superior gas impermeability and physical properties over a wide temperature range while maintaining excellent resistance to petroleum oils.
• It has a stable cycling capability from low to high temperature.
• Service temperatures are -51°C to150°C (-60°F to +300°F).
• Resistance to ozone, oxidation, weathering, and sunlight.
• Disadvantage: expensive.
CSM (Hypalon)
• Excellent resistance to oxygen, ozone, and most chemicals.
• Low gas permeability.
• Used for protective coatings.
• The working temperature range is considered to be -20°C to +150°C.