Anti-static stretch film for safer deliveries

A collaboration between German companies DUO PLAST AG and BASF is said to have resulted in the first stretch film approved for potentially explosive areas.

The manufacturer DUO PLAST AG has created DUO EX-TRA using the static dissipative polymer additive Elastostat, made by BASF.

Conventional films have a static charge and so are a safety hazard if used in flammable areas or near explosive materials. Before entering these potentially dangerous areas pallets must be repacked. As the new polyethylene blown film, DUO EX-TRA, has no ignition source electrostatics, wrapped pallets do not need repacking, say the manufacturers. The anti-static film has been designed for the chemical industry, for safe direct delivery.

Anja Oltmanns of BASF says Elastostat is based on thermoplastic polyurethane. ‘It works by building a conductive network inside the polymer matrix, e.g. low-density polyethylene (LD PE), to reduce the surface resistance into the dissipative range.’ This helps maintain the film’s stretchy and thin attributes.

Elastostat has electrical resistance of 10¹²-10⁹Ω. Oltmanns says it is humidity independent, highly compatible with non-polar polymers and ready to use for injection moulding and extrusion. The anti-static additive is approved for food by the US Food and Drug Administration and in the EU, and with other polymers for dry solids below 60°C.

Discussing the stretch film design, Nina Schnitzler from DUO PLAST AG says, ‘Without risk of static electricity, you can move your goods among EX (explosive)-Zones. No transhipping times. No additional human resources. No danger for your transport.

 ‘The new film with Elastostat is meant for industrial packaging and can be used as an outer packaging for all materials, e.g. cardboard boxes, canisters, drums etc.’

Tests for hazardous areas involved measuring the surface resistance of the anti-static stretch film, which fulfils the requirement of being less than 10¹¹Ω at 23°C, with a relative humidity of 20% in unstretched and stretched (260-280%) conditions.

The result is LD PE and linear-LD PE blown films with three or more layers, with the anti-static finish only in the outer layers.

The DUO EX-TRA film also contains the patented Duo Double Edge which has large holding forces. Schnitzler says this improves stability and results in around 26% less plastic.