Rubber (Kautschuk)

Rubber is preferred when high elasticity, flexibility and resilience of the material are required. Unlike plastics, rubber remains permanently dimensionally stable and tear-resistant even under severe stretching and compression. While plastics often break in a brittle manner or deform permanently, rubber returns to its original shape after loading. Rubber also has higher abrasion resistance and is better suited to applications that need to absorb shocks, such as seals, tyres or vibration dampers.

• Elasticity: rubber can be stretched considerably and returns to its original shape.

• Tear strength: high resistance to mechanical loads.

• Tightness: ideally suited for watertight and airtight applications.

• Resistance: resistant to abrasion, weathering and chemicals (depending on the type).

• Electrical insulation: good insulating properties, particularly with EPDM and silicone rubbers.

Natural rubber (NR)

• Origin: obtained from the latex of the rubber tree.

• Properties: very high elasticity, good tensile strength, but limited heat resistance and chemical resistance.

• Applications: tyres, conveyor belts, seals.

Synthetic rubber

Synthetic rubber is produced chemically and offers a wide range of properties:

Type	Properties	Typical applications
SBR (styrene-butadiene rubber)	Good abrasion resistance, cost-effective	Tyres, shoe soles
NBR (acrylonitrile butadiene rubber)	Resistant to oil and fuel	Seals, hoses
EPDM (ethylene propylene diene rubber)	Resistant to UV, ozone and heat	Roof waterproofing, automotive seals
CR (chloroprene rubber, neoprene)	Flame-retardant, weather-resistant	Protective gloves, sealing profiles
FKM (fluororubber, Viton®)	Heat-resistant, chemical-resistant	O-rings, high-performance seals

Natural rubber

• Harvesting: the latex is obtained by tapping the bark of the tree.

• Coagulation: the latex is coagulated by adding acids.

• Drying: the coagulated material is dried and processed into raw rubber.

Synthetic rubber

• Polymerisation: chemical reaction of monomers such as butadiene and styrene.

• Mixing: addition of fillers, vulcanising agents and plasticisers.

• Shaping: the material is shaped by processes such as extrusion, calendering or injection moulding.

The recyclability of rubber is limited, as vulcanised rubber cannot be completely returned to its original state. Instead, scrap rubber is mechanically shredded and added to new rubber compounds as recyclate. However, the proportion of recyclate is often limited, as too much scrap rubber impairs the mechanical properties of the compound. A large proportion of scrap rubber is recovered thermally, for example for energy generation in cement works.

Automotive industry

• Tyres: main component of modern vehicle tyres.

• Seals: for doors, windows and engine components.

Construction industry

• Sealing: EPDM seals for windows, façades and roofs.

• Vibration dampers: to prevent vibrations in buildings.

Medical technology

• Elastic products: manufacture of gloves, catheters and tubes.

• Prostheses: high-quality materials for medical applications.

Electrical engineering

• Cable insulation: protection against electrical influences.

• Seals: resistant to heat and chemicals.

• Elasticity: excellent for applications that require flexibility and restoring force.

• Resistance: resistant to weathering, chemicals and mechanical wear.

• Sustainability: natural rubber is a renewable raw material.

• Ageing: rubber can become brittle due to UV radiation, oxygen and ozone.

• Costs: high-quality synthetic rubbers such as FKM or CR are more expensive than standard rubbers.

• Recycling: the recycling of vulcanised rubber is limited and usually involves a loss of quality.

Property	Natural rubber	Synthetic rubber
Elasticity	Very high	Variable, depending on the type
Resistance	Limited against heat and chemicals	High, depending on the compound
Costs	Lower	Higher
Sustainability	Renewable	Depends on production

Rubber is an indispensable raw material in numerous industries. Its elasticity, abrasion resistance and adaptability make it a key material in modern manufacturing. Despite the challenges of recycling, rubber remains irreplaceable because of its unique properties in applications that require high flexibility and mechanical strength.