Magnetic coating composition
AssigneeMemorex Corporation
InventorsGregorio Brilovich, Irvin F. Masserant
Life of this patent
Estimating the term…
Abstract
A magnetic coating composition is disclosed which comprises a dispersion of magnetic particles in a solution of an epoxy resin having an average of between 1 and 3 epoxy groups per molecule and having an epoxy equivalent in the range about 400 to 4,000 and containing an organic acid which boils below 220.degree. C., the acid being present in amount equal to from 2 to 20% by weight of the contained magnetic particles. Magnetic recording media prepared by coating a substrate with the coating composition, subjecting the coated substrate to a magnetic field to orient the magnetic particles in a desired direction and then heating the coated substrate to evaporate the solvent and cure the resin exhibit high orientation ratios in the range 1.8 to 2.4.
Claims4
A magnetic coating composition comprising a dispersion of magnetic particles in a solution of an epoxy resin having an average of between one and three epoxy groups per molecule and having an epoxy equivalent in the range about 400 to 4,000 and containing an organic acid selected from the group consisting of formic, acetic and propionic acids in amount equal to from 2 to 20% by weight of the contained magnetic particles.
The method of preparing a magnetic coating composition which comprises
- a. forming a mixture of magnetic particles, a solution of an epoxy resin having an average of between one and three epoxy groups per molecule and having an epoxy equivalent in the range about 400 to 4,000 and an organic acid selected from the group consisting of formic, acetic and propionic acids, the quantity of acid being equal to from 0.5 to 5% of the weight of the magnetic particles,
- b. milling the mixture to disperse the magnetic particles in the solution,
- c. adding to the milled mixture a solution of a polyvinylacetal resin having a resin content amounting to 10 to 50% by weight of the epoxy resin and a further quantity of said organic acid sufficient to bring the total acid content to a level equal to from 6 to 20% by weight of the weight of the magnetic particles.
Dependencies are inferred from the claim text.