Inline plasma pretreatment

Optimal adhesion in multi-component injection moulding with Inline plasma pretreatment

Pretreatment procedures as priming, flaming and corona or plasma treatment are well known procedures for the improvement of bonding and adhesion.

Advantages of plasma treatment for multi component systems are

• Removal of organic constituents (cleaning)
• installation of reactive and/or active groups at the surface (activation)
• breaking open layers (oxide coatings)

From the multiplicity of the methods direct procedures like the inline-plasma pretreatment under atmospheric conditions (OpenAir-Plasma) is a potential alternative in multicomponent injection moulding with the key processing advantages:

• the mobility and directionality of the plasma source
• partial and localized treatment of contact areas of large parts
• Material-specific treatment of the semi-finished part directly before contact with a mating partner
• incorporation into production or directly into the process chain

plasma treatment directly in the mould

Inline activation of polymer surfaces by plasma treatment directly in the injection mould

• enables positive-joint composites to be made from combinations that were hitherto unable to adhere to each other, (for example with PBT/TPU)
• markedly improves adhesion of compatible combinations and
• reduces the influence of adhesion-relevant processing parameters. (for example with PA6/TPU)

The studies commenced to establish the inline plasma technology in the field of multi-component injection moulding are currently performed at the NMF in a collaborative venture between the companies Krauss Maffei Kunststofftechnik GmbH, PlasmaTreat GmbH and Neureder AG and the Institute of Polymer Technilogy. Basic application-oriented trials are performed on an appropriate experimental setup in a pilot plant of NMF that consists of a two-component injection moulding machine, a 6 axis buckling-arm robot and a variable plasma equipment.

Plasma-pilot plant at NMF

Companies who wish to follow the studies and participate in the results may do so within the context of an industrial group called "Inline Plasma Treatment in multi-Component injection Moulding".