Polymeric articles having antistatic properties and methods for their manufacture

Abstract

An article comprised of a polymeric material bearing a coating. The coating comprises a residual layer formed by applying and allowing to dry a mixture containing from about 7.5 to about 23.5 weight percent of a humidity sensitive antistatic surfactant compound and from about 10 to about 30 weight percent of a water soluble ink. The article possesses an electrostatic potential of from about -5 to about +5 kilovolts as measured at one inch from the coating. A process for producing a formed article which is relatively free from the effects of static electricity. The process includes the steps of topically applying a mixture comprising a humidity sensitive antistatic surfactant compound to a stock comprising a foamed polymeric material, conditioning the foam stock in a humidity-controlled environment effective to reduce electrostatic potential of the stock to between from about -5 to about +5 kilovolts, and thereafter forming the article from the conditioned foam stock. The polymeric material may comprise polystyrene and the water soluble ink may comprise a mixing white ink. The humidity sensitive surfactant is preferably comprised of a mixture of sodium alkyl sulfonates consisting essentially of sulfonates having the molecular formulas C.sub.10-18 H.sub.21-39 SO.sub.3 Na.

Dependencies are inferred from the claim text.