Hoechst Celanese Corporation

Celanese Acetate Limited

James Robert Walden

Hans-Tobias Macholdt

Werner Groh

Edward J Powers

Clinton Dale Felton

Baylor D Gibson

Harold W Davis

The disclosure disclosed a fabric made of cellulose acetate and/or cellulose triacetate, and optionally fibers of other selected substances, which are calendered at selected temperatures and pressures after having been water-wetted to a selected water content in order to bond the fibers of cellulose acetate and/or triacetate to one another and/or to fibers of the other selected substances. The selected calendering temperatures are from about 130&deg; C. to about 210&deg; C., preferably from about 160&deg; C. to about 190&deg; C.; the selected pressures are from about 500 to about 5000 psi, preferably from about 500 to about 2500 psi and most preferably from about 1000 to about 2500 psi; and selected water content is from about 20% to about 600% of fabric dry weight. The physical properties of the calendered fabric, for example the stiffness or hand resulting from different degrees of bonding can be changed by altering one or more of there parameters, either separately or in combination. The physical properties can also be changed by changed by changing the rate at which the fabric is passed between the calendering rollers or the type of rollers used, for example, smooth versus embossed or patterned rollers.

Thermal bonding of wet cellulose based fibers

The use of additives to produce polymer electrets with improved charge stability. In particular, the invention relates to the use of specific charge control agents used for toners that are blended with various polymers at suitable concentrations to enhance the charge lifetime of the electrets. The charge control agents include a triphenylmethane compound, a polymeric ammonium compound, and arylsulfide compound and azochromium complex.

Polymer electrets with improved charge stability

Growing community of inventors

Matthews, NC, United States of America

James Robert Walden