Rubber

Rubber is the main component of a rubber mixture . The rubber elements also determine the basic properties of the elastomer material. The basic properties include, for example, resistance to fuels and oils, heat and cold, weather, ozone and oxygen as well as chRubber is the basic raw material for rubber and elastomers. It forms the ‘elastic backbone’ of a rubber compound and, together with fillers, plasticisers and cross-linking agents, determines the subsequent properties of the vulcanised product – i.e. the finished rubber.

• Natural rubber (NR) – obtained from the milky sap of the rubber tree (latex)
• Synthetic rubbers – chemically produced rubbers such as NBR, EPDM, CR, FKM, etc.

Role of rubber in the rubber compound

The rubber determines the basic characteristics of the elastomeric material, including:

• Resistance to oils, fuels and lubricants (e.g. NBR, FKM)
• Behaviour in heat and cold (temperature range, cold flexibility)
• Resistance to weathering, ozone, UV radiation and oxygen (e.g. EPDM, VMQ)
• Resistance to chemicals and lubricants
• Basic mechanical properties such as elasticity, tensile strength, abrasion behaviour

Only through the addition of further formulation components – such as fillers, plasticisers, anti-ageing agents and cross-linking chemicals – that rubber becomes a material suitable for use in applications such as seals, O-rings, profiles, hoses or moulded parts.

Viscoelastic behaviour

A characteristic feature of rubber is its viscoelasticity

• Elastic component – the material can be stretched or compressed significantly and largely returns to its original shape
• viscous component – some of the energy applied is dissipated as heat; the material exhibits hysteresis and remains minimally deformed after loading

This combination is an advantage in many applications:

• Rubber can dampen vibrations and shocks
• it reduces peak loads instead of rigidly transmitting them
• at the same time, it remains sufficiently elastic to compensate for sealing gaps and tolerances

The small, permanent amount of deformation is characterised, for example, by the compression set – an important parameter in sealing technology.

Rubber in practice

• Seals, O-rings and flat gaskets
• Profiles and frame seals in the construction and automotive sectors
• Hoses and membranes in fluid and pneumatic systems
• Vibration dampers, bearing and buffer elements in mechanical engineering

Depending on the type of rubber (e.g. NBR, EPDM, VMQ, FKM, FFKM), the property profile can be tailored very specifically to the medium, temperature range and mechanical load – from oil-resistant hydraulic seals to weather-resistant profiles in façade construction.

emicals and solvents. A major advantage of rubber is its viscoelasticity, which means that it does not completely return to its original shape.