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Preparation of Magnetic Inks

IP.com Disclosure Number: IPCOM000085153D
Original Publication Date: 1976-Feb-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 13K

Publishing Venue

IBM

Related People

Gardineer, BA: AUTHOR [+2]

Abstract

This preparation of magnetic inks eliminates the use of NH(3), which in the large production of inks results in an air and effluent pollution problems.

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This is the abbreviated version, containing approximately 55% of the total text.

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Preparation of Magnetic Inks

This preparation of magnetic inks eliminates the use of NH(3), which in the large production of inks results in an air and effluent pollution problems.

The procedure for formulating the magnetic ink is as follows:

1. Precipitation of Fe(3)O(4) is done not with ammonia, but by addition of hydroxide of alkaline materials (Na, K,): (2)FeCl(3) + FeCl(2) + 8 NaOH ----->
Fe(3)O(4) + 8 NaCl + 4 H(2)O.

2. Immediately after precipitation, sodium oleate is added to coat particles of Fe(3)O(4).

3. Generation of oleic acid around particles is done not by heating but by chemical means, adding controlled amounts of H(2)SO(4) to adjust pH to 6.5-7:

(Image Omitted)

4. The oleic acid coated Fe(3)O(4) then settles out and can be rinsed several times.

5. The Fe(3)O(4) is dispersed into magnetic fluid by mixing with proper surfactants.

The above-processing technique lends itself to the preparation of both positive charged or negative charged ink colloids.

Cationic Ink (positive charged surfactant).

A solution of 378 grs FeCl(3) . 6 H(2)O was dissolved in 400 cc of water, heated to boiling and mixed in an ultrasonic bath with 160 grs FeCl(2) . 4 H(2)O dissolved in 300 cc of water. To the mixture a solution of 250 grs of NaOH dissolved in 800 cc of water was added while vigorously mixing with a stirring motor. Twenty seconds after this addition, a sodium oleate solution made by neutralizing 16 g oleic acid with 3 g NaOH and diluted to 250 cc was added. The pH of the mixture was then adjusted to p...