Conductive paper and method

Claim 1

A continuous, in-line method of preparing an electrically conductive, multi-ply structure for intercepting and dissipating electrostatic charges and discharges, said structure having at least one electrically conductive ply, and a plurality of non-conductive plies, and having sufficient mechanical strength to enable it to be formed into a container, or to be used as a component of a container, for packaging electrostatic sensitive articles to protect them against electrostatic charges and discharges, comprising: forming in a mixing vessel at least one aqueous slurry consisting essentially of a fibrous material, particles of an inorganic electrically conductive substance, said electrically conductive particles being present in an amount of at least about 5% based upon the weight of the fibrous material in said at least one aqueous slurry and an electroconductive polymer dispersant for the particles of the conductive substance said electroconductive polymer dispersant having a molecular weight of between about 500 and about 30,000, said electroconductive polymer being present in an amount of at least about 5% based upon the weight of said electroconductive particles; dispersing said particles in said mixing vessel in the presence of said fibrous material and the polymer dispersant to enable said particles to be substantially uniformly taken up by said fixedly supported on the fibers comprising the fibrous material; forming a plurality of separate aqueous slurries consisting essentially of a non-conductive fibrous material, transporting the slurry containing the particles of the conductive substance from said mixing vessel to a paper forming machine; adding a retention aid polymer to the slurry containing the particles of the conductive substance in an amount sufficient to agglomerate and compact said conductive particle supporting fibers; forming with the paper forming machine at least one ply in sheet form from said at least one slurry while said conductive particle supporting fibers are in an agglomerated and compacted condition to provide at least one conductive ply having as an integral part thereof a substantially continuous, uninterrupted, electrostatic charge intercepting barrier comprising fibers having particles of the electrically conductive substance fixedly supported thereon; forming separate, non-conductive plies in sheet form from said plurality of separate aqueous slurries consisting essentially of a non-conductive fibrous material; and combining said at least one conductive ply with said non-conductive plies to provide an integrated, multi-ply structure comprising a plurality of non-conductive plies, and at least one conductive ply, said at least one conductive ply being preselectively positioned with relation to the non-conductive plies of the structure to enable it to provide optimum protection against electrostatic charges and discharges, said structure having sufficient mechanical strength to enable it to be formed into a container, or to be used as a component of a container, for packaging electrostatic sensitive articles to be protected against electrostatic charges and discharges.