E.i. Dupont De Nemours and Company

University of California

Thomas Kenneth Bednarz

Allan Cairncross

John Edwin Gantzhorn, Jr

George Yeaman Thomson, Jr

Kurt Richard Mikeska

Jean Francois Woll

Ottmar Niederpruem

Michel Stachnik

Jacques Gilbert De Cauwer

Methods and associated apparatus are disclosed for use in mounting particles on and de-mounting particles from a substrate having an array of tacky and non-tacky areas. The particles can be either electrically conducting or electrically non-conducting. Selection of electrically conducting particles is preferred. The substrate having an array of tacky and non-tacky areas can either be electrically non-conducting (e.g., a dielectric substrate) or electrically-conducting. The methods involve use of first and second electrode plates with the substrate therebetween, the plates having applied thereto a direct current potential, which potential in preferred embodiments is reversed in polarity for a number N of cycles. Methods and articles are disclosed using an electrically conductive surface adjacent the tacky and non-tacky areas to minimize static buildup on the particles and tacky and non-tacky areas.

Electrostatic methods and apparatus for mounting and demounting particles from a surface having an array of tacky and non-tacky areas

This invention relates to flash spinning a plexifilamentary film-fibril strand and laying it down into sheet material including the step of subjecting the strand to an electrostatic charge. The invention is particularly focused on cleaning, and maintaining clean, the target plate of the electrostatic charging system by scrubbing or scouring the surface of the target plate with a highly abrasive brush moving at a relatively high speed. The target plate is selected to be abrasion resistant.

Corona charging of flash spun plexifilamentary film-fibril webs in poor

A conductive ceramic composition is disclosed which consists essentially of alumina, chromia, and magnesia, and is suitable for use as target electrodes in electrostatic fiber charging applications. Ceramics are disclosed which have exhibit volume resistivities of 10.sup.12 ohm-cm or less at 20.degree. C., and have excellent electrical stability and superior mechanical properties; and an electrostatic charging apparatus is disclosed which employs a ceramic electronic conductor having a volume resistivity of from about 1.times.10.sup.7 to 5.times.10.sup.10 ohm-cm and a hardness of at least 5 GPa.

Electrically conductive ceramics and their use in fiber charging

The aerodynamic shield members of the apparatus for electrostatically charging fibrous material disclosed in U.S. Pat. No. 3,860,369 are coated with a material having a resistance of between 5.times. 10.sup.12 and 10.sup.14 ohms/sq to reduce arcing at higher charge levels.

Growing community of inventors

Richmond, VA, United States of America

Thomas Kenneth Bednarz