Material
|
Hardness
(Shore A)
|
Temperature
Range
|
Comments
|
|
|
|
Excellent general purpose, low cost
compound, with good physical strength
and good compression set. Good
resistance to oil, fuel, water, and air.
|
Chloroprene
(Neoprene)
(CR)
|
|
|
|
Good general purpose, low cost
compound, with good resistance to flex
cracking, ozone impermeability,
abrasion, and compression set Good
in oil, fuel, refrigerants and fair in
water. Poor in aromatics.
|
|
|
|
Excellent impermeability for vacuum
service, non flammable phosphate
ester fluid resistance, and good
weathering, water swell, ozone, and
chemical resistance, except with
petroleum base derivitaves. Poor
compression set.
|
Natural Rubber
(Polyisoprene)
(NR)
|
|
|
|
Excellent resilience, cold temperature,
and good abrasion resistance,
compression set, tensile and low water
swell. Good for steam if no oil present.
Poor in heat, oil, fuel, ozone, and
solvent resistance.
|
Styrene- Butadiene
(Buna S)
(GR-S) (SBR)
|
|
|
|
Similar to natural rubber. (See above
for details)
|
|
|
|
Excellent impermeability, oil and fuel
resistance, and low temperature
flexibility. Good solvent, and
refrigerant resistance, compression
set, and ozone resistance. Poor
abrasion resistance.
|
Hypalon
Chlorinated
Polyethylene
(CSM)
|
|
|
|
Excellent ozone, weather, chemical
(except for fuels and solvents), and
good abrasion resistance,
impermeability for vacuum service, but
poor compression set.
|
Fluoro-Carbon
Elastomers
(Viton) (Kel-F)
(Fluorel) (FPM)
(CPM)
|
|
|
|
Standard high cost material for
excellent high temperature and
chemical resistance. Poor only in
caustics and ketones. Good
mechanical properties and good in Di
ester and Silicate ester fluids.
|
Silicones
(Si) (PSi)
(VSi) (PVSi)
|
|
|
|
Standard high cost compounds,
excellent water and dry heat
resistance. Poor tensile, and abrasion,
and poor oil, fuel and solvent
resistance.
|
Fluoro- Silicones
(LS 53)
(FSi)
|
|
|
|
Same as Silicones except good oil,
fuel, and solvent resistance.
|
Ethylene Propylene
(EP)
(EPM)
(EPT)
(EPDM)
|
|
|
|
Excellent resistance to steam, aging,
abrasion, and phosphate ester fluids.
Good compression set, ozone, ketone
and weather resistance. Poor
petroleum base resistance.
|
Polyurethane
Cast
Millable
Injection
(AU)
(EU)
|
|
|
|
Excellent elasticity, abrasion and flex
cracking resistance. Good
compression set, elongation and
solvent resistance (except ketones).
Extremely high tensile strength, but
poor temperature range and hot water
resistance, and poor with acids, and
alkali.
|
|
|
|
Excellent aging and high temperature
resistance. Good with oils and solvents
and phosphate ester fluids. Poor
abrasion and water resistance.
|
|
|
|
Excellent solvent and petroleum based
fuel and oil resistance. Good
resilience, weather, ozone resistance,
vacuum service and poor tensile,
abrasion and compression set
properties.
|
|
|
|
Excellent lubricity, chemical and
temperature resistance. Because of
cold flow and high mechanical
strength, Teflon does not seal well
unless very carefully designed. Can be
used as static seal readily, but as
dynamic seal needs mechanical
loading.
|
