Additives

Additives in rubber compounds perform a wide range of functions and, depending on the requirements of the application, can influence different properties of the material. The most common additives include:

Vulcanisation accelerators

These additives speed up the vulcanisation process, a chemical reaction in which raw rubber is given its final elastic form through the addition of sulphur and heat. Vulcanisation accelerators shorten the curing process, which increases production speed and improves efficiency.

Fillers

Fillers are additives used to improve mechanical properties such as strength, stiffness and abrasion resistance. A commonly used filler is carbon black, which not only improves hardness and wear resistance but also affects the colour of the rubber. Silica is another filler often used in rubber compounds to improve wet grip, particularly in tyres.

Plasticisers and flexibilisers

These additives, such as phthalates or oils, ensure that rubber retains its flexibility and elasticity, even at low temperatures. Plasticisers are used to improve the processability of the rubber compound and to increase the elongation of the finished product.

Antioxidants and anti-ageing agents

Antioxidants protect rubber compounds against degradation by oxygen and ozone, which can lead to cracking, embrittlement and material fatigue. Anti-ageing agents considerably extend the service life of rubber products, especially when they are used in environments exposed to extreme weather conditions.

Flame retardants

In certain applications, such as electronics or construction, it is important that rubber materials are flame-retardant. Flame retardants such as halogen compounds or phosphorus-based additives are added to reduce flammability and increase the safety of the material.

Additives are used in almost every rubber compound produced in industry. They are crucial for the performance and specific properties of the end products in a wide range of applications.

Automotive industry

In the automotive industry, rubber components such as seals, moulded parts, O-rings, hoses, profiles and, of course, tyres are constantly exposed to high stresses from temperature, friction and chemical influences. Additives such as antioxidants, carbon black and plasticisers ensure that these parts offer a long service life and high reliability even under extreme conditions.

Mechanical engineering

In mechanical engineering, rubber seals are often used in hydraulic and pneumatic systems. Here, resistance to pressure and abrasion is crucial. Additives such as fillers and vulcanisation accelerators provide the necessary strength and resistance of the materials.

Construction and infrastructure

Additives also play a key role in the manufacture of rubber seals and insulating materials used in the construction industry. Flame retardants and anti-ageing agents are used here to meet safety requirements and ensure a long product life.

The targeted use of additives in rubber compounds offers numerous advantages:

• Improved durability: anti-ageing agents and antioxidants considerably increase the resistance of rubber products to environmental influences.

• Optimised processing properties: additives such as vulcanisation accelerators and plasticisers make rubber compounds easier to process and reduce production times.

• Increased performance: fillers and plasticisers help to improve the mechanical properties of rubber, such as strength and flexibility.

1. How do additives affect the service life of rubber products?

Additives such as antioxidants and anti-ageing agents protect rubber products against external influences such as oxygen and UV radiation, which considerably extends their service life.

2. What is the difference between fillers and plasticisers in rubber compounds?

Fillers, such as carbon black or silica, improve the mechanical properties of rubber, while plasticisers increase the flexibility and processability of the material.

3. Are additives also used in natural rubber?

Yes, additives such as vulcanisation accelerators and fillers are also used in natural rubber compounds to optimise the properties of the material.

4. How is the amount of additives in a rubber compound determined?

The amount and type of additives depend on the specific requirements of the end product. Factors such as temperature resistance, elasticity and chemical resistance play a role.

Additives are indispensable for producing high-quality rubber compounds, as they specifically influence the properties of the materials. With additives, rubber products can be made more resistant, more flexible and longer-lasting. They are therefore a decisive factor for the performance and safety of rubber components in numerous industries, from automotive to construction.