Dow Corning Corporation

Judith M Sylvester

Harold L Vincent

Gary A Vincent

David J Kimball

There is disclosed the use of a quaternary ammonium salt of an alkoxysilane as a dispersant for magnetic pigment particles in the preparation of magnetic recording media. The dispersant of the present invention can bind to the pigment particles and may be substituted for conventional phosphate ester dispersants which are incapable of binding to the pigment and tend to migrate to the surface of such media, thereby adversely affecting recording media performance.

Quaternary ammonium salt of an alkoxysilane as a dispersant for magnetic

This invention relates to a stabilized ferromagnetic metal pigment which is produced by treating metal particles with a passivating reaction product comprising a silane-modified phosphate. The treated pigment is employed in the preparation of a magnetic recording medium which is resistant to storage at elevated temperature and humidity.

Method of stabilizing magnetic metal pigment

Stabilized magnetic metal pigment

An improved dispersant for magnetic media, comprising the reaction product of a phosphate ester and an alkali siliconate silylalkylphosphonate, is described. The dispersant can provide comparable magnetic properties in magnetic media at lower levels than are necessary for currently employed phosphate ester dispersants. A magnetic coating composition and a process for producing magnetic recording media, based on said improved dispersant, are also disclosed.

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Midland, MI, United States of America

Judith M Sylvester