Röchling offers a comprehensive range of ESD materials: A favourite experiment in the physics lesson is one where an electrostatic charge is applied to plastic film by means of friction. Likewise, in many areas of industry plant parts can be charged electrostatically by means of friction. When these voltages discharge, humans may be at risk or in areas prone to fire risk dust and gases may be ignited by sparkovers. Static charges may also be the cause of electromagnetic faults on sensitive equipment. Electrically conductive and antistatic plastics can help here.
Plastics with defined electrically conductive properties can dissipate electrostatic charges controlledly and lastingly. They are used in many areas of industry, such as the electronics and semi-conductor industry, ventilation, ventilator and pump construction, medical technology, the chemical and pharmaceutical industry, grain mills and other industries where bulk goods generate dust, the handling of flammable liquids and gases, e.g. at petrol stations, at airports and gas plants, the paper industry, fabric or film manufacture or mining. Thanks to its very many and varied property profiles the Röchling product range offers the highest level of safety for these applications.
If a discharge generates the necessary ignition energy in potentially explosive environments, known as EX zones, sparks may be discharged and the explosive materials thus ignited. The European ATEX (from French "ATmosphère EXplosive") directive 94/9/EC contains regulations for the use of components and systems in potentially explosive environments.
A human feels electrostatic discharges as a short electric shock only from 3000 volts up. Component parts used in the electronics and semi-conductor industry are much more sensitive. Even discharges of considerably less than 100 volts can affect or even destroy sensitive component parts (ESDS= electrostatic discharge sensitive devices). The result is lasting damage to or immediate failure of the component part. Materials coming into contact with such sensitive electronic components must therefore have electrically dissipative properties.
Röchling Industrial offers areas of industry which make use of the electrical conductivity of plastics a wide range of technical and high performance plastics. As well has "conventional" properties like outstanding chemical resistance, very high sliding properties or high abrasion resistance, flame retardant or self-extinguishing characteristics or suitability for use at high temperatures, they also have a specified electrical property - from antistatic to conductive.
Polystone® PPs EL
Polystone® PPs EL GK
Polystone® G-black EL
Polystone® M (PE-UHMW), Polystone® D (PE-HD)
Polystone® PVDF EL
SUSTAPEI ESD 90 (PEI)
SUSTAPEEK CF 30 (PEEK)
SUSTAPVDF ESD 60 (PVDF)
SUSTAMID 6 ESD 60 (PA 6)
SUSTAMID 6G ESD 90 (PA 6 G)
SUSTARIN C ESD 60 (POM)
SUSTARIN C ESD 60 PLUS (POM)
SUSTARIN C ESD 90 (POM)
SUSTARIN C ESD 90 PLUS (POM)
The insulation characteristics of a material are defined by its resistance to a current flowing through it. Continuity resistance applies only to the current flowing through the interior of the material and not to the part of the current flowing over the surface. The surface resistance measured between two electrodes applied to the surface of the material also applies to part of the current flowing on the inside.
For assessing the suitability of a material for an ESD application (ESD = ElectroStatic Dissipation) surface resistance is the more important of the two characteristics, because it decisively affects the electrostatic charging and discharging of a material. When selecting material, it must be ensured that the material used is not electrostatically chargeable, that is, the surface resistance is lower than 109 Ω.
Surface resistance can be subdivided into three levels of resistance:
Materials with surface resistance values lower than 106 Ω are electrostatically conductive. These materials are able to dissipate in the shortest possible time charge carriers applied to them. Because of the very short discharge time conductive materials are not suitable for all ESD applications, because the voltage peaks occurring here may cause damage, particularly to electrostatically sensitive electronic components.
Materials are described as electrostatically dissipative, if their specific surface resistance is between 106 Ω and 1012 Ω. Such materials are able to dissipate within a specified time charge carriers applied to them. These materials are only limitedly chargeable. Materials with a surface resistance lower than 109 Ω are not chargeable.
Materials with a specific surface resistance higher than 1012 Ω are described as insulating. Insulators have very low conductivity. For this reason applied charge carriers remain on the surface of these materials for a long time and are dissipated only slowly. Charges of many thousands of volts are thus possible without difficulty. Insulating materials are unsuitable for ESD applications.
A further electrostatic material characteristic is continuity resistance. When a material is modified, continuity resistance, as well as surface resistance, is often lowered. For a large number of applications continuity resistance is insignificant.