It is suggested for the biggest part of sealing applications and it
has a very common use. Nitrile (NBR) is a Butadiene - Acrylo Nitrile
(ACN) is a polymer. At HELEN RUBBER WORKS the percentage of acrylo nitrile
in the nitrile compound varies between 30% and 50%. The variation in
the percentage of ACN changes the volume, gas permeability, elasticity
and compression set of the compound used in mineral oils, grease and
fuel. Nitrile is very durable against aliphatic hydrocarbons (i.e. propane,
butane, petroleum etc.), mineral oils (lubricants, H, HL, HLP type of
hydraulic oils), greases, HFA, HFB, HFC, type hydraulic fluids, vegetal-animal
oils, light heating oil and diesel oil. For fuels and industrial fluids,
different mixtures are prepared. Our standard nitrile compound is recommended
to be used between -30°C and +105°C. For short period of applications,
it can be increased to +120°C.
It is a kind of elastomer which is made in such a way that a part or
complete part of NBR polymer is hydrogenized with double linked Butadien.
Vulcanized with Peroxide HNBR has durability against high temperature
and oxidation. Having higher temperature resistance and mechanical values
than standart NBR compound, HNBR is suggested for the temperature range
-30 and +150°C.
Silicon keeps its elasticity between -60°C and 200°C. It is not recommended
for dynamic applications. It has a good resistance against ozone, atmosphere
and lubricants where as it has a less durability against oxidizing lubricants
and some hipoits as well as lubricants of E.P. type.
This material under the trade mark Viton or Flourel has durability against
all types of greases, lubricants and solvents. And it has a good resistance
against many chemicals. It functions very properly in vacuum-systems
and in case of applications requiring low gas permeability. Viton keeps
its elasticity between -30°C and +225°C.
It has a great resistance to rupture, to tear and to wearing out between
the temperatures -45°C and 100°C. It has endurance against flame. Its
resistance against mineral oils with high aniline point, silicon oil,
grease and alcohole is good. It is also used in applications where endurance
for lubricant and atmospheric conditions are required.
It has a perfect durability against rupture, tear and wearing out in
the temperatures between -30°C and 100°C. And it has resistance to atmosphere
and ozone. Its resistance to mineral oils, grease and aliphatic hydrocarbon
is good. Especially, it is used as shaft stripper and high compressed
DIENE RUBBER (EPDM)
The temperature range is -40°C and 145°C. It has resistance against
break fluids, steam, phosphate and esther fluids.
Between the temperatures -50°C and 100°C its resistance against glycol
based brake fluids, inorganic and organic acids and alcohole is good.
It is used between the temperatures -60°C and 100°C and recommended
in applications where high flexibility is required.
Among the hydraulic-pneumatic systems it is the most common material
used. It has excellent form stability at elevated temperatures up to
80°C. One of the most important features is its low water absorbtion.
The temperature range is between -40°C and 140°C. For the quide ring,
POM filled with glass is used due to its high contact pressure value.