What are plasticisers?

External plasticisers are liquid or low-viscosity substances that are added to rubber and plastic mixtures and are interposed between the rubber and plastic layers. Polymer chains store. In contrast, internal plasticisers are chemically bound to the polymer structure in the form of side or end groups. Plasticisers reduce the intermolecular forces between the polymer chains and lower the glass transition temperature of the polymers, reduce hardness and make the material more pliable. At the same time, they ensure a lower viscosity, which facilitates processing.

 

Function of plasticisers

Internal plasticisers have a physical effect: they are deposited between the polymer chains and reduce their intermolecular forces. This leads to

  • Increased elasticity and bending capacity
  • Less brittle in the cold
  • Improved processing (e.g. for Extrusion or Moulding presses)
  • Adjustment of the Shore hardness in the desired area
  • Influencing density, Rebound behaviour and haptics
  • As external plasticisers are not chemically bound, they can be lost over time or washed out on contact with the media

 

The selection of the right plasticiser depends on the type of polymer, application temperature, media contact and regulatory requirements - especially in sensitive areas such as medical technology or food packaging.

 

Types of plasticisers

  • Mineral oil-based plasticisers: e.g. paraffin oil, aromatic oils
  • Phthalates: formerly standard, now partly restricted (e.g. DEHP, DOP)
  • Adipate, Sebacate, Citrate: for PVC and other thermoplastics
  • Vegetable oil-based / biocompatible plasticisers (e.g. for TPE or medical applications)
  • Special plasticiser for high temperature resistance or reduced migration

 

Plasticisers can also be specifically modified in order to LABS-freedom or to minimise migration.

 

Use of plasticisers

  • Rubber products with high flexibility: Seals, Rubber caps, Suction cup
  • Increasing low-temperature flexibility
  • TPE- and PVC moulded parts, e.g. cable sheathing or profiles
  • Rubber composite parts in which soft zones are functionally integrated
  • Medical and consumer goods with contact to skin or food
  • Automotive, e.g. for noise and Vibration damping