Permanent antistatic primer layer

摘要

There is provided a method for preparing a biaxially oriented polyester sheet or web, with improved antistatic properties, comprising the steps of (i) stretching said polyester sheet or web first in one direction and second in a direction perpendicular thereto (ii) coating said hydrophobic polyester sheet or web, either before stretching or between said first and second stretching operation, on one or both sides, with a transparent antistatic primer layer, wherein the coating composition of said transparent antistatic primer layer comprises (1) a dispersion of a polythiophene with conjugated polymer backbone and a polymeric polyanion compound and (2) a latex polymer having hydrophilic functionality. The primer layer is coated from an aqueous composition and does not show a substantial change in resistivity depending on relative humidity or wet processing.