SKF - Industrial Shaft Seals

Polyacrylate elastomer
Polyacrylate elastomers are more heat resistant
than nitrile rubber or SKF Duralip. The operating
temperature range for polyacrylate elastomers
lies between –40 and +150 °C (–40 and +300 °F)
and in some fluids the upper limit may be extended
to 175 °C (345 °F). Seals of polyacrylate
are resistant to ageing and ozone and are also
suitable for use with lubricants containing EP
additives. They should not be used to seal water,
acids or alkalis etc. Dry running should be
avoided.
Silicone rubber
Silicone rubber is characterized by high thermal
resistance and can withstand temperatures
ranging from –70 to +160 °C (–90 to +320 °F).
Silicone rubber absorbs lubricants, thereby minimizing
friction and wear. SKF silicone rubber
seals are particularly suitable for applications
with very low or very high temperatures and for
low-friction sealing of bearing arrangements.
They are not very resistant to oxidized oils or
certain EP additives and should be protected
against abrasive substances. Sealing lips made
of silicone rubber should not be exposed to dry
running.
Wear resistance
The wear resistance of a seal depends largely on
the sealing lip material, as well as on the shaft
surface finish, type of lubricant, circumferential
speed, temperature and pressure differentials.
A comparison of wear resistance for various
sealing lip materials used by SKF is provided in
diagram 2. It is valid for seals of the same size,
operating under identical conditions.
1
Wear resistance
Diagram 2
Silicone
rubber
Polyacrylate
elastomer
Nitrile rubber
Carboxylated nitrile rubber (SKF Duralip)
Hydrogenated nitrile rubber (SKF Duratemp)
Fluoro rubber (SKF Duralife)
Polytetrafluoroethylene
33