An elastomer is an elastic polymer with the physical property of elasticity. Each of the monomers which link to form the polymer is usually made of carbon, hydrogen, oxygen and/ or silicon. Elastomer gaskets are usually thermosets requiring a curing process involving heat and the addition of sulfur or other equivalent curatives, and elastomers may also be thermoplastic.
Buna-N is a synthetic rubber that has good resistance to oils and solvents, aromatic and aliphatic hydrocarbons, petroleum oils, and gasoline over a wide range of temperatures. It also has good resistance to caustics and salts, but only fair acid resistance. It is not suitable for strong oxidizing agents, chlorinated hydrocarbons, ketones, or esters. It is suitable over a temperature range of approximately -60°F to 250°F (-51°C to 121°C).
Hypalon® has good acid, alkali, and salt resistance. It resists weathering, sunlight, ozone, oils and commercial fuels such as diesel and kerosene. It is not good in aromatics or chlorinated hydrocarbons, and has poor resistance against chromic acid and nitric acid. Its normal temperature range spans -50°F and 275°F (-46°C and 135°C).
Chloroprene is a synthetic rubber suitable for use against moderate acids, alkalies, and salt solutions. It has good resistance to commercial oils and fuels. It is not resistant to strong oxidizing acids, aromatic or chlorinated hydrocarbons. Its temperature range spans from approximately -60°F to 250°F (-51°C to 121°C).
This synthetic material has good resistance to strong acids, alkalies, salts and chlorine solutions. It is not suitable for use in oils, solvents, or aromatic hydrocarbons. Its temperature range spans -70°F to 350°F (-57°C to 177°C).
Perfluoroelastomer (FFKM/FFPM) parts resist over 1,800 different chemicals, including concentrated nitric acid, sodium hydroxide, ethylene diamine and steam while offering the high temperature stability of PTFE 620°F (327°C). Kalrez® is a registered trademark of DuPont.
Fluorocarbon elastomer has good resistance to oils, fuel, chlorinated solvents, aliphatic and aromatic hydrocarbons and strong acids. It is not suitable for use against amines, esters, ketones, or steam. Its normal temperature range spans -15°F to 450°F (-26°C to 232°C).
Natural rubber has good resistance to mild acids and alkalis, salts and chlorine solutions. It has poor resistance to oils and solvents, and is not recommended for use with ozone. Its temperature range is limited to between -70°F and 200°F (-57°C to 93°C).
Envelope gaskets utilizing PTFE jackets feature low minimum seating stresses, excellent creep resistance, high deformability and choice of a variety of filler materials, including corrugated metal and rubber sheets.
Slit Type / V Type / Style 800 is sliced from cylinders and split from the outside diameter to within approximately 1/16” (1.5 mm) of the inside diameter. Bearing surface is determined by filler dimensions. The gasket OD normally rests within the bolt hole circle and the ID is approximately equal to the nominal ID of the pipe. Available in sizes to a maximum OD of 24”.
Milled Type / Square Cut / Style 820 is machined from cylinder stock. The jacket is machined from the OD to within approximately 1/32” (0.8 mm) of its ID. The jacket’s ID fits flush with the pipe’s bore and its OD nests within the bolts. Available in sizes up to a maximum OD of 24” (609 mm).
Formed Tape Type is large diameter (over 12 NPS) and irregularly shaped envelopes are formed from tape and heat sealed to produce a continuous jacket construction.
SBR is a synthetic rubber that has excellent abrasion resistance and good resistance to weak organic acids, alcohols, moderate chemicals, and ketones. It is not recommended for ozone, strong acids, fats, oils, greases, or most hydrocarbons. Its temperature range spans from approximately -65°F to 250°F (-54°C to 121°C).
Silicone rubbers have good resistance to hot air. They are unaffected by sunlight and ozone. They are not suitable for use against steam, aliphatic or aromatic hydrocarbons. Suitable temperature range spans -65°F to 500°F (-54°C to 260°C).
Vegetable fiber sheet is a tough pliable gasket material manufactured with paper making techniques that utilize plant fibers and a glue-glycerine impregnation. It is widely used for sealing petroleum products, gases and a wide variety of solvents. If a more compressible material is required, a combination cork-fiber sheet is available. Both the vegetable fiber sheet and combination cork-fiber sheet have a maximum temperature limit of 250°F (121°C).