Minnesota Mining and Manufacturing Company

Imation Corporation

Alvin M Berg

James G Carlson

Ramesh C Kumar

Jeffrey T Anderson

Robert P McCollam

Daniel Y Chang

Kevin K Kuck

Benedict L Bezenek

Stephen A Johnson

John C Harvey

Thomas M Bohlsen

The invention provides novel macromonomer and carboxyl functional polyurethanes having a high carboxyl content. The invention further provides dispersions, coatings and magnetic recording media comprising these polyurethanes, or blends or copolymers of these polyurethanes with quaternary ammonium compounds. The invention further provides novel dispersions, coatings and magnetic recording media comprising combinations of carboxyl functional polyurethanes having a high carboxyl content with quaternary ammonium polymers.

Carboxylic acid functional polyurethane polymers and blends thereof used

Disclosed is a video tape suitable for use in high speed contact duplication. The magnetic layer comprises a magnetic pigment dispersed in a polymeric binder at amounts of magnetic pigment between 75 and 88 percent by weight of the magnetic layer with a total pigment loading (magnetic+nonmagnetic pigments) of at least 80 percent by weight. The tape is provided with a backside coating comprising at least two nonmagnetic pigments dispersed in a polymeric binder, the first nonmagnetic pigment, being a conductive material and having a relatively small particle size of between about 0.015 and 0.15 .mu.m, and the second nonmagnetic pigment having a relatively large particle size of between about 0.15 and 1.5 .mu.m. The magnetic layer has a lubricant absorption value of at least 4 and a surface roughness of between 5 and 15 nm. The backside coating has a surface roughness of between 10 and 150 nm. The polymeric binder of either or both of the magnetic layer and the backside coating may preferably comprise a hard component resin and a soft component resin, wherein the soft component resin is a polyurethane having a plurality of pendant carboxy groups.

Video recording tapes suitable for high speed contact duplication

Growing community of inventors

Roseville, MN, United States of America

Alvin M Berg