What are primers?
Primers are an adhesion-promoting primer that is applied to a surface to improve the adhesion between the substrate and rubber, plastic, adhesive or paint. In rubber technology, primers play a central role in the production of Rubber-metal composite parts, Rubber-plastic composite parts or when preparing components for painting or bonding.
Functions of primers
Primers act as a link between different materials. They activate inert oxide layers, improve wettability and generally increase the surface energy of the substrate. As a result, they enable uniform, permanent adhesion - especially on smooth, inert or non-porous materials such as metals, Polyamides or thermoplastics.
A distinction is made depending on the application:
- Physically acting primers, e.g. by dissolving the surface
- Chemically reactive primers, e.g. with functional groups for cross-linking
- Special primer for LABS-free applications or high temperature ranges
Primers are applied in a thin layer by brush, spraying or dipping - often in combination with a second bonding agent or adhesive system.
Primer applications
Primers are indispensable in many manufacturing processes, especially in
- Rubber-metal composite partse.g. with the Vulcanisation of elastomers on steel or Aluminium
- Multi-component injection moulding: for the connection of TPE with PA or PC
- Coatings on plastics with low surface energy
- Bonded joints in vehicle construction, mechanical engineering or apparatus engineering
- LABS-free applications, e.g. in automotive painting
The right choice of primer depends on the material pairing, environmental influences (temperature, media) and the planned further processing.