Surface treatment method for magnetic particles
AssigneeRicoh Company, Ltd.
InventorsHiroshi Yamashita, Kenkichi Muto
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Abstract
A surface treatment method for magnetic particles is disclosed, which comprises the steps of activating magnetic particles by application of heat thereto, treating the surface of the magnetic particles with a reactive silane coupling agent, bringing the treated magnetic particles into contact with at least one polymerizable vinyl-type monomer, polymerizing the monomer to form a polymer, and coating the surface of the magnetic particles with the polymer.
Claims8
A surface treatment method for uncoated magnetic particles consisting of magnetic material comprising the steps of activating by heating said uncoated magnetic particles to a temperature of 100.degree. C. to 500.degree. C., treating the surfaces of said magnetic particles with a reactive silane coupling agent, mixing the silane-treated magnetic particles with at least one polymerizable vinyl monomer, polymerizing said monomer to form a polymer, and thereby coating the surfaces of said magnetic particles with said polymer.
A method for treating the surfaces of magnetic particles to improve their dispersibility and their surface affinity with respect to polymerizable monomers, which consists essentially of the steps of:
- heating magnetic particles to a temperature of from 100.degree. to 500.degree. C. effective to remove adsorbed water from said magnetic particles whereby to activate said magnetic particles, said magnetic particles having a particle size of from about 0.01 to about 1 micrometers and consisting of a magnetic material selected from the group consisting of magnetic metals, magnetic metal alloys, magnetic metal oxides and ferromagnetic materials;
- then coating said magnetic particles with from 0.1 to 5 wt. %, based on the weight of said magnetic particles, of a reactive silane coupling agent and heating same at 100.degree. to 120.degree. C. whereby to bond said silane coupling agent to the surfaces of said magnetic particles;
- then mixing said magnetic particles with a polymerizable vinyl monomer component which can be polymerized by radical polymerization and polymerizing said monomer component whereby to form a polymer coating on each of said magnetic particles, which coating is firmly bonded to its magnetic particle by said silane coupling agent.
Dependencies are inferred from the claim text.