Minnesota Mining and Manufacturing Company

Daniel Y Chang

James G Carlson

Ramesh C Kumar

Suman K Patel

Nelson T Rotto

Ravindra L Arudi

John C Haidos

Robert P McCollam

Kevin K Kuck

Alvin M Berg

Keith J Modert

Thomas M Bohlsen

Benedict L Bezenek

Stephen A Johnson

John C Harvey

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

Magnetic recording medium, comprising a magnetic layer provided on a nonmagnetizable substrate, wherein the magnetic layer comprises a magnetic pigment dispersed in a polymeric binder. The polymeric binder comprises a nonhalogenated vinyl copolymer, wherein the vinyl copolymer comprises a plurality of pendant nitrile groups, a plurality of pendant hydroxyl groups, and at least one pendant dispersing group. Preferably, the binder also includes a secondary polymer component.

Magnetic recording medium whose magnetic layer incorporates

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Vadnais Heights, MN, United States of America

Daniel Y Chang