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US 5,648,124 AGranted
Process for preparing magnetically responsive microparticles
AssigneeSeradyn, Inc.
InventorJames J. Sutor
Life of this patent
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Abstract
Magnetically responsive microparticles and a method for their production are described. Oppositely charged core particles and magnetite are heterocoagulated, redispersed and optionally coated. The microparticles are colloidally stable and have negligible retentivity. Having now fully described the invention, it will be apparent to one of ordinary skill in the art that many changes and modifications can be made thereto without departing from the spirit or scope of the invention as set forth herein.
Claims17
A method for the preparation of microparticles which are responsive to a magnetic field comprising the steps of:
- 1) providing an aqueous dispersion comprising electrically charged material which is responsive to a magnetic field and electrically charged core particles wherein said electrically charged material and electrically charged core particles are oppositely charged;
- and allowing said material and said core particles to heterocoagulate;
- 2) optionally adding a heterocoagulant to said dispersion obtained in 1) to effect further heterocoagulation of the core particles and the material;
- 3) adding a polymeric dispersant to the heterocoagulated core particles and material obtained in 1) or 2) so as to provide dispersed microparticles which are responsive to a magnetic field;
- 4) optionally crosslinking the polymeric dispersant on the microparticles produced in 3);
- 5) optionally coating the dispersed microparticles obtained in 3) or 4) with at least one coating polymer or with at least one polymerizable monomer and at least one polymerization initiator, followed by polymerization of said monomer.
3 more elements
Dependencies are inferred from the claim text.