Typical Properties of Common Elastomers (Rubber Compounds)

Common Name(s)	Designation	Composition	General Properties1	General Chemical Resistance
Common Name(s)	Designation	Composition	General Properties1	Resistent to:	Attacked by:
Neoprene	CR	Chloroprene	Good Weathering Resistance. Flame retarding. Moderate resistance to pertroleum-based fluids.	Moderate chemicals and acids, ozone, oils, fats, greases, many oils, and solvents.	Strong oxidizing acids, esters, ketones, chlorinated, aromatic and nitro hydrocarbons.
EPDM	EPDM, EPM	Ethylene-propylene- diene; Ethylene-propylene	Excellent ozone, chemical, and aging resistance. Poor resistance to pertoleum-based fluids.	Animal and vegetable oils, ozone, strong and oxidizing chemicals.	Mineral oils and solvents, aromatic hydrocarbons.
Buna-N	NBR	Nitrile-butadiene	Excellent resistance to pertoleum-based fluids. Good physical properties.	Many hydrocarbons, fats, oils, greases, hydraulic fluids, chemicals.	Ozone (except PVC blends), ketones, esters, aldehydes, chlorinated and nitro hydrocarbons.
Silicone	Q, Si	Polysiloxane	Excellent high and low temperature properties. Fair physical properties.	Moderate or oxidizing chemicals, ozone, concentrated sodium hydroxide.	Many solvents, oils, concentrated acids, dilute sodium hydroxide.
SBR	SBR	Styrene-butadiene	Good physical properties and abrasion resistance. Poor resistance to petroleum-based fluids.	Most moderate chemicals, wet or dry, organic acids, alcohols, ketones, aldehydes.	Ozone, strong acids, fats, oils, greases, most hydrocarbons.
Butyl	IIR	Isobutene-isoprene	Very good weathering resistance. Excellent dialectric properties. Low permeability to air. Good physical properties. Poor resistance to petroleum-based fluids.	Animal and vegetable fats, oils, greases, ozone, strong and oxidizing chemicals.	Petroleum, solvents, coal tar solvents, aromatic hydrocarbons.
Natural, Gum Rubber	NR	Isoprene, natural	Excellent physical properties including abrasion and low temperature resistance. Poor resistance to petroleum-based fluids.	Most moderate chemicals, wet or dry, organic acids, alcohols, ketones, aldehydes.	Ozone, strong acids, fats, oils, greases, most hydrocarbons.
Isoprene, Polyisoprene	IR	Isoprene, synthetic	Similar to natural rubber.	Similar to natural rubber.	Similar to natural rubber.
Hypalon	CSM	Chloro-sulfonyl- polyethylene	Excellent ozone, weathering, and acid resistance. Good and abrasion and heat resistance. Fair resistance to petroleum-based fluids.	Similar to Neoprene with improved acid resistance.	Concentrated oxidizing acids, esters, ketones, chlorinated, aromatic, and nitro hydrocarbons.
Acrylic, Poly Acrylate	ABR, ACM	Acrylate-butadiene, copolymer of acrylic ester and acrylic halide	Excellent resistance to high temperature, oil and air, ozone, and weathering. Poor low temperature properties. Not recommended for water service.	Ozone, extreme pressure, lubricants, hot oils, petroleum solvents, animal and vegetable fats.	Water, alcohols, glycols, alkali, esters, aromatic and halogenated hydrocarbons, phenol.
Urethane	AU, EU	Polyethylene-apdate, Poly (oxy-1, 4, butylene) ether	Good aging and excellent abrasion, tear, and solvent resistance. Poor high temperature properties.	Ozone, hydrocarbons, moderate chemicals, fats, oils, greases.	Concentrated acids, ketones, esters, chlorinated and nitro hydrocarbons.
Chlorinated- polyethylene	CPE	Chlorinated- polyethylene	Excellent ozone and weathering resistance; good heat resistance. Moderate resistance to petroleum-based fluids.
Viton4, Fluoro-elastomer	FPM	Hexaflouropropylene- vinylidene flouride	Excellent oil and air resistance both at low and high temperatures. Very good chemical resistance.	All aliphatic, aromatic and halogenated hydrocarbons, acids, animal and vegetable oils.	Ketones, low molecular weight esters and nitro containing compounds.
Butadiene rubber	BR	Polybutadiene	Excellent abrasion resistance and low temperature properties. High resilience.	Similar to SBR	Similar to SBR
Kalrez4	AFMU	Tetraflouroethylene- flouronitrosomethane- perflourobutyric acid	Excellent chemical resistance. Excellent high and low temperature properties.
Hydrin, Herchlor	CO	Polychloromethyl oxirane	Excellent oil and ozone resistance. Good flame resistance and low permeability to gases. Fair low temperature properties.	Similar to nitrile with ozone resistance.	Ketones, esters, aldehydes, chlorinated and nitro hydrocarbons.
ECH, Hydrin, Herchlor	ECO	Ethylene oxide and chloromethyl oxirane	Good low temperature properties. Excellent oil and ozone resistance. Fair flame resistance. Low permeability to gases.	Similar to nitrile with ozone resistance.	Ketones, esters, aldehydes, chlorinated and nitro hydrocarbons.
Fluoro-silicone	FSi	Flourocarbon		Moderate or oxidizing chemicals, ozone, aromatic chlorinated solvents, bases.	Brake fluids, hydrazine, ketones.

Standard Gasket and Rubber Products carries a wide variety of rubber products for an even broader array of applications. Rubber hardnesses commonly range from 30 to 90 durometer (Shore A) and are available in many standard, semi-standard, and custom compounds to cover virtually any requirement. We carry a large inventory containing some styles of most of the classes of elastomers listed above.
The above table gives general information regarding common rubber genres and is intended to aid in material selection and design of rubber parts and products. Rubber compounding is a very broad and technical field, as basic elastomers are typically mixed with various chemicals and ingredients (and even with each other) to obtain desired physical properties and control costs. (Yes, like everyone else, rubber manufacturers are constantly seeking ways to cut their costs, including cheapening their products.)
Most commercial rubber products are made to proprietary formulas held in confidence by the companies producing them. There are, therefore, literally infinite possible formulations within each genre of rubber listed below...and (consumer beware) THEY ARE NOT ALL EQUAL! A wide range of variations on physical properties like tensile strength, elongation percentage, and abrasion resistance can be found amongst different commercial rubber products made of the same basic elastomer -- and these are all factors that usually greatly affect the quality and durability of rubber seals, cushions, and other rubber products. Other factors like chemical resistance and temperature range also vary, but normally to a lesser degree, which makes the following information useful for the purpose of pointing in the right general direction as far as a rubber compound is concerned.
Dealers of rubber products will generally be happy to accommodate requests as generic as 'Neoprene', 'Silicone', or any other class of rubber, but that doesn't necessarily serve the consumer's interest. At least some of the features listed above and/or others are usually directly relative to the overall performance and cost of a rubber product, especially regarding the longevity of its elastomeric properties. In general, cheaper grades of rubber carry less resistance to elements and stresses that breakdown the molecular structure of rubber, making it stiff and brittle rather than rubbery. Physical testing can determine how well a rubber seal or gasket, for instance, works in a given application, but only laboratory tests can reveal the underlying qualities that bear upon how long it will work.
No reputable rubber compounder would mix, mold, extrude, or calender rubber without testing its physical properties, and consumers should know that this information bears directly on the true value of the materials they offer. For various, mostly benign reasons, physical properties are often only available on request, but they should be readily available from any reputable dealer of rubber products. In many cases it is well worth a few pennies more to get a rubber gasket or seal that is more likely to perform better for longer, but it is always worth while to know what your buying.