From another point of view, it is renown that one of the reasons that plastic materials are widely used in certain fields such as electrics and electronics, resides in their strong electro-insulating properties. In these fields, the thermoplastic polymers have easily replaced traditional construction materials thanks to their processabilility and to their project flexibility. These particular characteristics have allowed a rapid transition toward miniaturisation of electric/electronic components.
As its known, all medals have a reverse side: this positive characteristic (the electro-insulating power), in certain fields and with certain applications, causes problems which have no easy or immediate solution. One of these is the build-up of electrostatic charges on the surface of insulating materials, charges which can even reach high voltages and which, under certain conditions, can provoke sparks with the formation of electric fields and arches.
These phenomena have a particularly negative, even catastrophic, effect whenever flammable or explosive substances are present in the work environment, or in the presence of fuel passages, etc.
With the proliferation of the use of plastic materials, it has become unavoidable for competent safety authorities to consider the problem with a systematic approach. The European Community has recently published a directive called ATEX 94/9/EC; which has become mandatory for all the Union States as of July 2003. The name ATEX comes from the initials of the French term Atmosphères Explosibles, and applies to all equipment, components, accessories (electrical and mechanical) and systems which are or could be used in locations characterised as explosive environments. It expresses the essential safety requirements for protective equipment, components and systems destined to be used in potentially explosive environments. The under evaluation equipment must be inspected in compliance with the requirements of the regulation and only if they satisfy the required conditions, may they carry the marking required by the regulation.
It is evident that there is a need to consider dissipative plastic materials, in other words material capable of avoiding accumulation of electrostatic charges on the surface of manufactured products. Making plastic conductive may seem a rather easy task. Today additives can be found on the market precisely for this purpose.
The task becomes more burdensome when it is necessary to develop thermoplastic compounds characterised by constant conductivity values and contained in closed and pre-established limits, while maintaining the polymers’ favorable performance. LATI has been dealing with these problems for some time; for more than 20 years the company has been offering LATISTAT compounds which, as a common characteristic, have a low electric resistivity value.
These products, which are ideal in regard to dissipation of electrostatic charges, are available in black. In the last years, the range of partially electro-conductive products has widened with the introduction of two new types:
LATI has recently enlarged these ranges: today an extremely complete package is available to satisfy the most varied requirements. In order to corroborate the commitment and to provide clear information to the interested markets, LATI has published a technical sheet (available on our website) which deals with the ATEX directive and the compounds which meet its requirements.