Elastomers
NR : Natural Rubber
SBR: Styrene Butadiene Rubber
CR : Chloroprene Rubber (Neoprene)
NBR Nitrile Rubber
EPDM EPDM Rubber
CSM: Hypalon Rubber
VMQ : Silicone Rubber
FKM : Viton Rubber
NR - NATURAL RUBBER
Natural rubber is obtained from rubber wood. Although there are many types, only the type of Havea Brasiliensis growing in the Amazon region is used commercially. It is not a homogeneous product by its natural structure, however, notwithstanding it is classified as different product groups according to analytical and appearance evaluation criteria.
Properties
Mechanical properties such as excellent tensile strength, elasticity and tear resistance
A wide toughness range of 35 to 90 Shore A.
High elasticity, excellent dynamic properties and low compression set.
Excellent electrical properties.
It is precise towards ozone. The resistance to atmospheric conditions can be improved by the addition of antiozonants combined with waxes.
Temperature range -50 to 90 ° C.
SBR- STYRENE BUTADIENE RUBBER
More than half of synthetic rubbers produced in the world are SBR. SBR contains approximately 23% styrene. The increase in this rate causes the increase of toughness and also regress in temperature resistance and flexibility.
Properties
They require reinforcing annealer filling materials to provide good mechanical properties and higher wear resistance than natural rubber can be achieved.
They are similar to natural rubber but they are better aging and temperature resistance.
It has lower flexibility comparing with natural rubber.
It has moderate tear, ozone and atmospheric resistance.
Temperature range -50 to 110 ° C.
CR- CHLOROPRENE RUBBER (NEOPRENE)
It is the rubber that gives the most balanced combination of the expected properties. The chlorine atom increases the oil strength level and thus places it between the natural rubber and the nitrile rubber.
Properties
Excellent wear resistance and super mechanical properties.
Low elasticity of natural rubber at low toughness but high elasticity at 60 Shore A and more toughness.
Offers good temperature and ozone resistance.
Flame retarded.
Good adhesion to the metal.
Temperature range -25 to 125 ° C.
NBR - NITRILE RUBBER
They are classified as low ACN (18-24%), medium ACN (34%) and high ACN (50%) depending on the amount of ACN. By increasing the amount of ACN:
Oil and fuel resistance increases.
Tensile strength, abrasion resistance, toughness, temperature resistance and sealing properties increase.
Flexibility values reduce at low temperatures.
Properties
Resistant to oils and can be formulated for applications requiring high temperatures.
It has good mechanical properties.
It does not leak gas.
Aging properties are moderate.
Property adhesion to metal is good.
The low temperature resistances are moderate but can be used in applications reaching up to -40 ° C with the use of proper plasticizers.
Temperature range -30 to 120 ° C.
EPDM - EPDM RUBBER
Ethylene and propylene copolymer (EPM) can only be baked with peroxide and radiation, but standard sulfuric baking method can be used by adding Dien (EPDM) to them, thus the tear resistance is increased.
Properties
Excellent resistance to aging, ozone, ultraviolet ray and atmospheric conditions.
Excellent electrical properties and radiation resistance.
Moderate metal adhesion property.
Temperature range -40 to 120 ° C. However, 140 C can be formulated for continuous operation.
CSM - HYPALON RUBBER
Properties
Excellent resistance to oxidation, ozone and atmospheric conditions.
Excellent resistance to hydrocarbonated solvents.
Resistance to flame
Moderate metal adhesion property.
Temperature range -35 to 140 ° C.
VMQ - SILICONE RUBBER
Unlike other synthetic rubbers, the molecule chain does not contain carbon, it only includes silicone and oxygen atoms.
Properties
It has excellent heat resistance in dry environments (200- 220 C). There may be a decrease in thermal resistance due to hydrolysis in the case of aging at contact with high pressure steam (130-140 C) or in closed environments without oxygen.
Ozone, ultraviolet radiation and atmospheric conditions do not change its properties.
It has good insulation properties.
It has the self extinguishing property. The residues (silica) resulting from long-term burning resulting from flame exposure are excellent insulators.
It is physically innocuous, so it is proper for medical applications.
Temperature range -70 to 220 ° C.
FKM - VITON RUBBER
They are known as fluoroelastomer rubber. Chemical resistance and low and high temperature resistance are directly proportional to the amount of fluorine contained.
Properties
It is resistant to very high temperatures. 250 C for continuous operation and 300 C. for intermittent operation .
It has very high chemical resistance.
It has the self extinguishing property.
It has low deformation property at high temperature.
Low temperature range -30 to 50 ° C.