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Preparation of an Aqueous Magnetic Fluid by Peptization Technique

IP.com Disclosure Number: IPCOM000089186D
Original Publication Date: 1977-Sep-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 1 page(s) / 13K

Publishing Venue

IBM

Related People

Kovac, Z: AUTHOR

Abstract

It was believed that coating of Fe(3)O(4) particles in situ is essential for their subsequent transformation into magnetic ink , since only coated Fe(3)O(4) nonionic (TRITON* N-101) and cationic (ETHOQUAD** 0/12) surfactants are adsorbed and thus form a stable colloidal dispersion in water.

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Preparation of an Aqueous Magnetic Fluid by Peptization Technique

It was believed that coating of Fe(3)O(4) particles in situ is essential for their subsequent transformation into magnetic ink , since only coated Fe(3)O(4) nonionic (TRITON* N-101) and cationic (ETHOQUAD** 0/12) surfactants are adsorbed and thus form a stable colloidal dispersion in water.

Long chain organic anions such as oleate, amino dipropionate (DERIPHAT 154) and lauryl sulphate have been used for coating of Fe(3)O(4) particles.

Cationic surfactant has been substituted by anionic (TRITON X-202) (2) or DERIPHAT 151C. All previous attempts to make magnetic ink without nonionic surfactant resulted in gel.

Here it is shown that the coating of Fe(3)O(4) is not necessary and that two surfactants can be successfully replaced by one, such as cocoamine propionic acid (DERIPHAT 151C). If magnetic fluid is not used as a printing ink in a magnetic ink jet printer, then the addition of solvents is not required. In such a way a simple magnetic fluid (Fe(3)O(4) + H(2)O + DERIPHAT 151C), with lower concentration of solids (for the same magnetic moment) and lower viscosity, is obtained. Example 1-with no solvents.

378 g Fe C1(3) and 212 g Fe SO(4) (fertilizer grade) are dissolved in 3 liters of H(2)O. There is then added 500cc (58% NH(4)OH) in an ultrasonic bath with mechanical stirring. After precipitation, the Fe(3)O(4) is washed with 6 liters of hot deionized water, and excess water is then removed by centrifugations. The...