Development of a novel material for electronic circuit boards based on foamed high temperature thermoplastic resins
At present, printed circuit boards for electronic applications are not recyclable and generally require the use of environmental critical flame-retardants. Moreover substrates for flexible and for high frequency applications consist of very cost intensive base materials.
The objective of this work was to develop a polyetherimid foam as an inherent flame protectivesubstrate material. This material is recyclable and can be continuously processed by extrusion. Foaming saves material, costs and weight. Furthermore it significantly improves the dielectric properties of the material. As an additional advantage, thermoplastic substrates are shapeable in three dimensions.
However, printed circuit boards having pores usually are considered as critical and are not desired. In order to meet the demands of electronic industry, smooth surfaces, isotropic material properties and plating through has to be realised. Furthermore the penetration of liquid media into the substrate has to be prevented. For these reasons the main research focused on the development of closed celled extruded PEI foams with preferably small cell diameters, high cell densities and homogeneous cell size distributions.
In order to transfer these basic laboratory results to industrial production scale, an extrusion line was dimensioned for production scale in cooperation with the company Reifenhäuser Maschinenfabrik GmbH. On this basis, the construction and assembling of the extrusion line was done by Reifenhäuser.
The transfer of the laboratory results was successful with physical, as well as with chemical blowing agents. The PEI-substrates foamed by the production scaled extrusion line were tested regarding the main properties in order to determine the suitability for application and regarded to be well suited.Lesen Sie die deutsche Zusammenfassung auf Kunststoffe.de
Printed circuit board, Foam extrusion, Coextrusion, Morphology, Foam, closed celled, High temperature thermoplastic, Polyetherimide, PEI, Recycling, Flame retardant, High frequency, shapeable, Weight saving
Institute / chair: Fakultät für Angewandte Naturwissenschaften der Universität Bayreuth
Technical consultant for expert services: Prof. Dr.-Ing. Volker Altstädt (Betreuer), Prof. Dr.-Ing. Ernst Schmachtenberg
Publication year: 2006
Provider: Wissenschaftlicher Arbeitskreis Kunststofftechnik (WAK) / Kunststoffe.de
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