NITRILE (NBR)
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.

HNBR
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.

SILICONE (MVQ)
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.

VITON (FKM-Flourel)
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.

NEOPRENE (CR)
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.

POLYURETHANE (PU)
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 sealing element.

ETHYLENE-PROPYLENE DIENE RUBBER (EPDM)
The temperature range is -40°C and 145°C. It has resistance against break fluids, steam, phosphate and esther fluids.

STYRENE BUTADIEN RUBBER (SBR)
Between the temperatures -50°C and 100°C its resistance against glycol based brake fluids, inorganic and organic acids and alcohole is good.

NATURAL RUBBER (NR)
It is used between the temperatures -60°C and 100°C and recommended in applications where high flexibility is required.

POLYACETAL (POM)
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.