TABLE OF CONTENTS The demand for antistatic, electromagnetic shielding and related additives in the plastics industry is driven partly by sales of electrical and electronic equipment, much of which requires antistatic packaging and housings. Antistats have an important role in office equipment, reducing paper jams. Clean rooms for the manufacture of chip trays and silicon wafer cases need antistatic and other additives with low ion contamination and low volatile content, which implies pure substances. Medical monitoring equipment and aircraft instrumentation need to be protected from electronic interference.
Automotive requirements for plastic fuel systems need protection against static discharge. There is also a demand for antistats in the chemical process industry because of flammable liquids, and in medical and pharmaceutical products.
Ideally, an antistatic agent should be permanent. It should not lose its effect, as blooming types do, by migrating too quickly to the surface where it could be removed by washing or abrasion. Its action should be independent of the relative humidity, and it should allow the product to be light coloured or even transparent, which rules out carbon black. The antistatic agent should not rule out food contact applications. The industry has been addressing these problems, and considerable developments have taken place.
The technique used to achieve permanence with other additives such as antioxidants and plasticisers has often been to increase the molecular weight of the additives. In the case of antistatic...
