Plastics are mostly electrical insulators. The development of a static charge on two plastic film surfaces during mutual contact occurs by the transfer of electrons from one film surface to the other during rubbing or rapid separation. It is an undesirable consequence of insufficient conductivity especially in polymers with a very low tendency to absorb moisture and static discharge can reach several thousand volts per cm.
Antistats are divided into two general categories, external and internal. Internal antistatic additives are incorporated in the polymer matrix. The controlled incompatibility causes migration to the surface. There it forms a polar layer that absorbs water from the atmosphere. This layer is able to conduct / dissipates the charges. External antistats are topical agents applied to the surface. Washing the surface or repeated handling removes external antistats, thus requiring reapplication. The antistatic additive forms an interconnecting or percolate network and dissipate the static.