General Elastomeric Properties
Two types are most commonly used - smoked sheets and pale crepe. They are alike except in color and odor. Pale crepe is used for light colors and when odor is objectionable. Both possess exceptional elastic qualities and have good resistance to water and acids. They are compatible with synthetic rubbers and are often used in blends. Low compression set and stress relaxation, good electrical insulation and good resistance to abrasion, tear and fatigue. Best choice for applications requiring low heat build-up, such as tires, vibration, mounts springs and bearings. Other applications include hoses, conveyor belts, gaskets, seals, rolls and rubberized fabrics.
C.R. Chloroprene Rubber(CR) (Neoprene) Resists fats, oils and petroleum products. Stands up well in sunlight. Low flammability - burns when exposed to flames, but self-extinguishes when flame is removed. Generally good ozone, aging and chemical resistance. It has good mechanical properties over a wide temperature range.
Polyisoprene (IR) is a substitute for natural rubber and has very similar characteristics. Can be used in lower temperature applications than natural rubber.Styrene Butadiene Rubbers (SBR)Synthetic substitutes for natural rubber. Cures more slowly than natural rubber. Resistant to non-petroleum based automotive brake fluids, silicone oils and greases, glycols, alcohols, water, solutions of acids, alkalis and salts. Isoprene-Isobutylene Rubber (I.I.R., Butyl) has excellent resistance to aging, heat, sunlight and ozone. Low gas & moisture permeability; high damping, excellent electrical insulation; good resistance to dry heat and steam.
Chlorinated Butyl (Chlorobutyl) Exceptional heat stability, low compression set, low permeability to gasses and good resistance to chemicals, oxidation and tearing. Used for O-rings, gaskets, vacuum seals, membranes, steam hoses and pharmaceutical closures.
Nitrile Butadiene Rubber (N.B.R., Buna N) Nitrile, chemically, is a copolymer of butadiene and acrylonitrile. Acrylonitrile content is varied in commercial products from 18% to 48%. As the nitrile content increases, resistance to petroleum base oils and hydrocarbon fuels increases, but low temperature flexibility decreases. Due to its excellent resistance to petroleum products, and its ability to be compounded for service over a temperature range of -65 to +275°F(-54 to +135°C), nitrile is the most widely used elastomer in the seal industry today. Inherently nitrile does not possess good resistance to ozone, sunlight or weather, but this can be substantially improved through compounding.
Polyacrylic (ACM) High oil resistance and dry heat resistance up to 350°F. Used primarily in applications requiring combined resistance to heat, oils, and oil additives such as O-rings, lip seals and gaskets.
Epichlorohydrin (Hydrin) (CO, ECO, GECO) Ozone resistance, broad temperature range and oil resistance. Typical applications include seals, gaskets, diaphragms, hoses, belting, wire and cable jackets, coated fabrics and printing rolls.
Thiokol Polysulfide (T) More inert than most synthetics. High resistance to oil, gasoline and aromatic solvents-lacquer thinners. Applications include gasoline and aromatic fuel hoses, coating and printing rolls, gas meter diaphragms, O-rings, pulleys, sealants and coated paper gaskets.
Silicone and Fluoro-Silicone Rubber (Q, MQ, VMQ, FMQ, FVMQ) High and low temperature stability, exceptional release from sticking, resistance to aging, ozone and sunlight, good dielectrics and outstanding water repellency. Applications include electrical insulators, ignition cables, gaskets, O-rings, static seals, oxygen masks, food and medical grade tubing and roll coverings.
Millable Urethanes (AU/EU) Exceptional tensile strength. Abrasion and low temperature resistance. Typical applications include hydraulic seals, gaskets, diaphragms, hoses, and wheels for skate boards.
Hypalon®, Chlorosulfonated Polyethylene Rubber (CSM) High ozone and corona resistance, heat resistance up to 300°F and good color stability. Widely used in electrical applications as protective jacketing when resistance to heat, flame, ozone, weather, corrosion, chemicals and oils are important. Other applications include coatings, weather resistant membranes, hoses and acid tank linings.
Fluoro Elastomers, fluorocarbon (Viton®, Fluorel) (FKM)
For extreme heat resistance-temperatures ranging to +500°F. Resistance to abrasion, oil and chemicals is outstanding. Good resistance to ozone, weathering and flame. Main uses are as O-rings, shaft seals, gaskets, fuel hoses, diaphragms, and cable sheathing for extreme conditions.
Polybutadiene (BR) Excellent abrasion resistance. Good low temperature qualities. It is mainly used in blends with other rubbers to manufacture mechanical goods in order to increase resilience, to improve their low temperature flexibility, or to reduce their heat build-up on flexing.
Ethylene Propylene Copolymer (EPM) Resistance to chemicals, chemical solutions, heat and ozone.
Ethylene Propylene Diene Terpolymer (EPDM) Excellent in water, steam, heat, weather, detergents, ozone and many chemicals. Applications include O-rings, gaskets, window and door seals, wire and cable insulation, under-hood applications, hoses, and waterproofing sheets.
TFE Propylene (Aflas) TetrafluoroethylenePropylene Rubbers This elastomer is a copolymer of Tetrafluoroethylene (TFE) and propylene. Its chemical resistance is excellent across a wide range of aggressive media.
PTFE (polytetrafluoroethylene) This compound is impervious to virtually all fluids and gasses ranging from -320°F to 450°F Only molten alkaline metals and certain halogenated compounds will attack it.
Molded Splice – many gaskets and seals can be produced economically by splicing extruded shapes to form gaskets, a radius corner or square comer can be spliced to fit a specified shape