Foam retains its antistatic properties

Plastazote is a novel antistatic foam packaging material that does not depend on environmental factors for its performance.

Critical electronics devices, assemblies and equipment are known to be susceptible to "static zap".

As little as 100 to 200V can cause serious problems for a power mosfet and 250 to 2000V can cause irreparable damage to a CMOS transistor.

The damage can be catastrophic or partial, but either way it can cause untold problems with equipment performance.

When you consider that moving a common plastic bag can generate anything from 1.2 to 20kV it should come as no surprise to learn that great efforts are made to prevent static build-up during the manufacture, use, transport and storage of such equipment.

Where resistance to impact (cushioning) is also required, many resort to the use of antistatic foam for the neutralisation of these static charges.

But under certain environmental conditions this type of material can offer little static protection.

The long-established technology uses a migratory additive that diffuses to surfaces where it picks up atmospheric moisture to provide a level of surface electrical conductivity.

The maximum surface resistivity generally accepted is 1Tohm/sq, and antistatic foams are generally batch tested to this prior to release.

However, the maintenance of this surface conductivity is an equilibrium process depending on ambient humidity, temperature, and previous exposure conditions.

Exposure to desert conditions of very low humidity and high temperatures may well result in the surface resistivity exceeding the agreed maximum.

Clearly some military electronic equipment runs a significant risk of static damage when used under these conditions and therefore runs an unacceptable risk of failure in the field.

To overcome this potential problem, Zotefoams has developed a permanently static dissipative, protective foam under the Plastazote brand.

This foam incorporates a noncorrosive, totally encapsulated conductive component in its makeup that provides bulk conduction of static without the need for atmospheric moisture.

This permanently static dissipative foam is insensitive to environmental conditions.

The Plastazote Foam LD30 SD is expanded using pure nitrogen gas, ensuring there are no contaminating residues from any chemical blowing agents.

It can be thermoformed and offers excellent chemical resistance, isotropic physical properties along with good cushioning performance, and a surface resistivity of 10Mohm/sq that puts it in the static dissipative range.

Wherever "static zap" could pose a problem and conditions of use cannot be guaranteed then it is prudent to use a static dissipative material that does not depend on climatic conditions for its performance.

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