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Method for Determining the Effectiveness of Dispersants for Magnetic Oxide

IP.com Disclosure Number: IPCOM000046305D
Original Publication Date: 1983-Jul-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Bradshaw, RL: AUTHOR [+4]

Abstract

This method subjects a liquid mixture of a dispersant and magnetic oxide particles to two very different levels of mechanical mixing. The resultant particle size analysis enables one to classify the ability of the dispersant to function with that particle. That is, the more similar the two particle size analysis results, the better is the dispersant.

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Method for Determining the Effectiveness of Dispersants for Magnetic Oxide

This method subjects a liquid mixture of a dispersant and magnetic oxide particles to two very different levels of mechanical mixing. The resultant particle size analysis enables one to classify the ability of the dispersant to function with that particle. That is, the more similar the two particle size analysis results, the better is the dispersant.

This method is particularly useful to classify the ability of dispersants to properly disperse chromium dioxide particles in a polymer/solvent coating ink, which coating ink is used to coat a substrate, in the process of manufacturing magnetic recording media.

In the practice of this method, the magnetic particles usually in an amount of about 0.01 gram/cc for CrO2 particles, and slightly more for Fe2O3 particles, are first mixed in a liquid solvent of the type that will be used in formulating the coating ink. The proportions of the mixture are such that the mixture will transmit light, since the particle analysis equipment to be subsequently used depends upon light transmission for its operation.

The dispersant being evaluated is then added to this mixture, for example, one drop of a 1% to 10% solution of the dispersant for each 1 to 2cc's of the solution.

This mixture is then hand-shaken to produce what appears to be adequate mixing. The sample is then placed in the sample compartment of a light scattering, sub-micron particle size analyzer...