Antistatic Coatings

Electronic packaging examples: static charges on plastic surfaces lead to numerous problems. Coating with Clevios™ produces plastic surfaces with an antistatic finish

Many plastics can be coated with PEDOT:PSS, including polycarbonate, polyethylene, polyethylene terephthalate, polyamide, and polypropylene. A surface activation such as corona or plasma treatment should be performed prior to coating PET and polyolefin parts to enhance adhesion to the substrate.

Typical applications for Clevios™ based antistatic and static dissipative coatings on plastic surfaces are:

Thermoformable coatings can be obtained by using „soft“ binders, e.g. contained in the ready to use formulation Clevios™ F PVA. Such coatings can be stretched by more than 200% during deep drawing. The initial surface resistivity is increased by one or two orders of magnitude.

To assist customers in their formulation work with Clevios™ conductive polymers, we have developed several coating formulations that contain Clevios™ P. These coating formulations have been optimized for individual substrates, such as PVC, polycarbonate, glass, etc. at different wet film thicknesses and surface resistivities and are mainly used for dissipation of static surface charges on various substrates. The coatings may be applied by conventional coating methods such as brushing, spin-coating, printing processes, spraying, dipping, and roller-coating techniques.

Clevios™ Coating Guide Formulations include:

CPP 105D
For antistatic coatings with higher conductivity, good adhesion properties on plastic and glass surfaces, and resistance to both aliphatic and aromatic hydrocarbon solvents.

CPP 134.18D
For highly transparent static dissipative coatings with good adhesion properties on polycarbonate or PVC plastic surfaces. Good for dip-coating applications.

CPP 141D
For the application of clear, hard, alcohol-resistant, antistatic coatings with good adhesion properties on aluminium, polycarbonate, and PVC surfaces.

CPG 130.6
For scratch-resistant antistatic coatings with good adhesion properties on glass surfaces.

Static charges on films and plastic surfaces leads to numerous problems. Coating with Clevios™ permits surfaces to be given an antistatic finish. Virtually all types of plastics can be coated with PEDOT, including polycarbonate, polyethylene, polyethylene terephthalate, polyamide, and polypropylene. A surface activation such as a corona treatment should be performed prior to coating in the case of PET and polyolefins to enhance adhesion to the substrate.

Typical applications for Clevios™-based antistatic and static dissipative coatings on plastic surfaces:

Coating of glass with Clevios™ formulations
Clevios™ can be used to produce transparent, conductive coatings on glass.
Typical applications for Clevios™

By combining Clevios™ with silanes, e.g. tetraethoxysilane, high hardness, scratch resistance, and surface resistance can be obtained. For achieving optimum hardness curing temperatures of about 180°C are required.

Scratch-resistant antistatic coating
Guide formulation CPG 130.6 allows the application of antistatic coatings with good scratch resistance.
Surface resistance: < 10E6 Ohm/sq
Pencil hardness: 9 H
Quantity of Clevios™ P used per m²: approx. 2g (spray application)

Higher conductivity can be achieved by using guide formulation CPP 105D or the ready to use formulation Clevios™ F 010. The hardness of the coating is however, lower than when using guide formulation CPG 130.6.

Surface resistance: < 10E3 Ohm/sq
Quantity of Clevios™ P used per m²: approx 6 g
The Clevios™ coatings can be either applied by spraying or the spin-coating method.

Clevios™ P is a waterborne dispersion of the polymer complex poly(3,4-ethylenedioxy-thiophene)/ polystyrene sulfonate (PEDOT/PSS). The dispersion consists of sub-micrometer sized gel particles which upon drying form a continuous film which is conductive and transparent.

Clevios™ P is typically considered a raw material and is most often formulated by end users into a coating for plastics, glass and other substrates. To assist customers in their formulation work with Clevios™ P, we have developed several coating formulations. These coating formulations have been optimized for specific substrates, such as PVC, polycarbonate, glass, etc. at different wet film thicknesses and surface resistivities. The coatings may be applied by conventional coating methods such as brushing, spin-coating, printing processes, spraying, dipping, and roller-coating techniques. Other binding agents may be added.

Some of the guide formulations contain N-Methyl-pyrrolidon to lower the surface resistivity of the coatings after drying. Similar results are obtained by adding other conductivity enhancers like DMSO (Dimethylsulfoxide), N,N-Dimethylformamide, N,N-Dimethylacetamide and Ethylene glycol., For more information about different formulations, please see the Guide Formulations.

The coatings are physically oven dried at temperatures between 80 to 140 °C. The drying time depends on coating thickness, temperature and air humidity and should be determined by appropriate application tests. The minimum drying time is limited by the evaporation rate of water from the polymer gel to about 30 to 60 s under practical conditions.