What are fillers?

Fillers are powdery or fibrous additives that are added to rubber or plastic compounds in order to specifically influence physical properties, processability or cost structure. In elastomer processing, they influence, among other things Hardness, Abrasion resistance, density, reinforcement, but also colour and thermal conductivity. Fillers are a central element in the Compounding - i.e. the development of rubber compound formulations.

 

Properties and types of fillers

Fillers can basically be divided into two categories:

  • Active fillers: improve mechanical properties (e.g. tear resistance, Abrasion)
  • Inactive fillers: mainly influence processability and costs, without a major reinforcing effect

 

Frequently used fillers in rubber technology:

  • Carbon blacks for mechanical reinforcement, UV protection and black colouring
  • Chalk (CaCO₃) as a cost-effective volumetric filler to reduce costs
  • Talc improves the gliding properties and dimensional stability
  • Kaolin / clayfor improving firmness and increasing volume
  • Silica (silicic acid) for improved abrasion resistance
  • Glass fibres / Aramid fibres for targeted reinforcement and dimensional stability
  • Metal oxides / Barium compounds for shaping weight, density, shielding effect, fire protection e.g. Al(OH)3

 

Application of fillers

Fillers are used in practically every technical rubber compound - e.g. for

 

Fillers have a decisive influence on both the processing properties and the subsequent product properties and are used specifically to adjust Rebound resilience, The materials are used to analyse the properties, formability, thermal conductivity, electrical properties and cost structure.