Moldable ferromagnetic particles and method

• US 5,637,402 A
• Filed: 04/23/1996
• Issued: 06/10/1997
• Est. Priority Date: 12/16/1994
• Status: Expired due to Fees

• Current Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Original Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Inventors: Gay, David E.
• Primary Examiner(s): Ryan, Patrick
• Assistant Examiner(s): YAMNITZKY, MARIE ROSE
• Application Number:
  US08/635,834
• Time in Patent Office: 413 Days
• Field of Search: 428/403, 428/407, 428/323, 428/327, 428/328, 523/205, 523/206, 523/210, 523/220, 523/223
• US Class Current: 428/403
• CPC Class Codes: C08K 9/08 Ingredients agglomerated by treatment with a binding agent
• CPC Class Codes: C08K 9/10 Encapsulated ingredients
• CPC Class Codes: H01F 1/0558 bonded together
• CPC Class Codes: H01F 1/0578 bonded together
• CPC Class Codes: H01F 1/113 in a bonding agent
• CPC Class Codes: H01F 1/26 by macromolecular organic substances
• CPC Class Codes: Y10T 428/254 Polymeric or resinous material
• CPC Class Codes: Y10T 428/256 Heavy metal or aluminum or compound thereof
• CPC Class Codes: Y10T 428/2991 Coated
• CPC Class Codes: Y10T 428/2998 including synthetic resin or polymer

Abstract

Moldable ferromagnetic particles and method of making a magnetizable molding therefrom. The ferromagnetic particles are spray-coated with a slurry comprising insoluble thermoplastic particles suspended in a solution of a soluble polymer to produce a coating on the ferromagnetic particles which comprises a majority of the insoluble thermoplastic particles embedded in a lesser amount of a binder polymer. When compression molded, the insoluble thermoplastic particles form a continuous matrix for the ferromagnetic particles.

Claims

1. A mass of moldable particles for compression molding into a magnetizable product which comprises a plurality of ferromagnetic particles dispersed throughout a polymeric matrix, said moldable particles each comprising a ferromagnetic particle having a first size and a coating thereon encapsulating said ferromagnetic particle, said coating comprising at least about 70% by weight of a plurality of thermoplastic particles dispersed throughout a polymeric binder embedding said thermoplastic particles wherein said binder is deposited onto said ferromagnetic particles from a solvent for said binder, and said thermoplastic particles are smaller than said first size and are selected from a group of thermoplastics which are only partially soluble in, or completely insoluble in, said solvent.

2. A mass of moldable particles according to claim 1 wherein said thermoplastic particles are selected from the group consisting of polyphenylene sulfide, polyphthalamide, polybenzimidazole, polyamides, polyesters and fluorocarbons.

3. A mass of particles according to claim 1 wherein said binder is selected from the group consisting of polyetherimide, polyacrylate, polystyrene, polycarbonate, and polyethersulfone.