Process for preparing magnetic polymer particles
US4774265A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 29, 1986 |
| Grant date | Sep 27, 1988 |
| Priority date | — |
| Expiry date | Jul 29, 2006 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/2998
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Magnetic polymer particles prepared by treating compact or porous polymer particles with a solution of iron salts and, if desired, salts of other metals which are capable of forming magnetic ferrites, in which the solution swells or penetrates into the particles. Iron hydroxide and possible other metal hydroxides are precipitated, for instance by raising the pH value, and the particles are optionally heated. In the iron salts used the ratio between di- and trivalent iron is suitably such that magnetic iron oxide is formed directly. It is also possible to use oxidizing or reducing groups or additives to obtain such a ratio. When other metal salts are used in addition to iron salts, the operation is carried out in the same manner. For instance, when Mn.sup.++, Co.sup.++ or Ni.sup.++ salts are used in addition to Fe.sup.++ salts, the divalent iron is oxidized to trivalent so that magnetic ferrite is obtained. The polymer particles which are treated with metal salts preferably contain metal-binding groups. Such groups are incorporated for instance by using monomers which contain said groups for the preparation of the polymer particles, or the groups are incorporated in the polymer part…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.