Coatings for EMI/RF shielding

Citation

Bean, J. (1998), "Coatings for EMI/RF shielding", Pigment & Resin Technology, Vol. 27 No. 6. https://doi.org/10.1108/prt.1998.12927faa.001

Coatings for EMI/RF shielding

Coatings for EMI/RF shielding

With the continual increase in the number and types of communication receivers, shielding of these receivers from EMI (electro-magnetic interference) and RFI (radio frequency interference) has become increasingly important. Equipment particularly susceptible to interference includes fast logic circuits as in computers and electronic controllers, signal conditioning circuits, amplification circuits, disc reading heads, modem inputs, multiplexers, electro-optical isolators, and cardiac pace makers.

The author recalls that originally conductive coatings containing graphite (still used for shielding of electrostatic discharge on petrol tanks) and nickel particles were much in favour for shielding. Then in the last decade electroplating, electroless coating, vacuum metallising and ion coating became much in favour. Now, conductive coatings, including for plastics mouldings are again being widely used.

With this in mind, the Paint Research Association (PRA) of Teddington, in partnership with Chemical and Polymer and the Electrical Research Association are organising a Conference on "Conductive Coatings and Compounds", to be held in Brussels, 21-23 June 1999. Although the primary aim is for EMI/RF shielding, papers on other types of conductive compounds will be welcomed since it may be important to encourage cross fertilisation between the different branches of conductive composite production as many aspects such as dispersion, curing behaviour and adhesion are common.

As stated, the range of electronic equipment is increasing; while size-decrease and integration leads to higher sensitivity to stray radiation. The electronic component housing is now thermally and electrically insulating plastic, which unlike metal housings, does not shield against incoming and outgoing radiation. Suggested topics for the conference where electro-magnetic screening of polymer housing is achieved by conductive paints, can include paint types such as solvent, aqueous, powder, high solids, supercritical spray, automotive primers. Resin types can include acrylic, epoxy, fluoro/silicone, polyurethane, vinyl. Topics for the additives can include metals, metallised plastics and inorganics, oxides, carbon/graphite, form and morphology.

Further details of the Conference are available from Janet Saraty, PRA, 8 Waldegrave Road, Teddington, Middlesex, UK TW11 8LD. Tel: +44 (0)181 614 4811. Fax: +44 (0)181 614 4812.